Multispecific molecules binding to TCR and uses thereof

Abstract

Provides herein are multifunctional molecules comprising T cell receptor variable beta-binding moieties and cytokines, and methods of treating conditions or diseases in a subject using the same.

Description

WSGR Docket No. 53676-759.601MULTISPECIFIC MOLECULES BINDING TO TCR AND USES THEREOFCROSS REFERENCE

[0001] This application claims the benefit of U.S. provisional Application No. 63 / 688,112 filed on August 28, 2024, which is incorporated herein by reference in its entirety.BACKGROUND

[0002] Currently available molecules designed to redirect T cells to promote tumor cell lysis for cancer immunotherapy typically target the CD3 epsilon (CD3e) subunit of the T cell receptor (TCR). However, there are limitations to this approach. Previous studies have shown that, e.g., low doses of anti-CD3e monoclonal antibody (mAb) can cause T cell dysfunction and exert immunosuppressive effects. In addition, anti-CD3e mAbs bind to all T cells and thus activate a large number of T cells. Such non- physiological massive activation of T cells by these anti-CD3e mAbs can result in the production of proinflammatory cytokines such as IFN-gamma, IL- 1 -beta, IL-6, IL- 10 and TNF-alpha, causing a “cytokine storm” known as the cytokine release syndrome (CRS), which is also associated with neurotoxicity (NT). Thus, there is a need for improved T cell receptor-binding molecules that redirect T cells for cancer immunotherapy.SUMMARY

[0003] In an aspect, provided herein is, inter aha, a composition comprising an IL-21 mutein polypeptide comprising a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, wherein the IL-21 mutein polypeptide comprises an aromatic amino acid substitution of He at position 8 of SEQ ID NO: 2193.

[0004] In another aspect, provided herein is a composition comprising an IL-21 mutein polypeptide, wherein when a polynucleotide comprising a sequence encoding the IL-21 mutein polypeptide is expressed in a cell:(a) the ratio of the amount of a full-length IL-21 mutein polypeptide produced to the amount of a less than full-length IL-21 mutein polypeptide produced is higher than the ratio of the amount of a corresponding full length IL-21 wild-type polypeptide produced to the amount of a less than full-length IL-21 wild-type polypeptide produced when a polynucleotide comprising a sequence encoding a IL-21 wild-type polypeptide is expressed in a cell; and / or(b) the amount of the full-length IL-21 mutein polypeptide produced is higher than the amount of the corresponding full-length IL-21 wild-type polypeptide produced when the polynucleotide comprising a sequence encoding the IL-21 wild-type polypeptide is expressed in a cell.

[0005] In another aspect, provided herein is a composition comprising an IL-21 mutein polypeptide, wherein the IL-21 mutein polypeptide is less susceptible to proteolytic cleavage when expressed in a cell compared to a corresponding IL-21 wild-type polypeptide when expressed in a cell.

[0006] In some embodiments, the IL-21 wild-type polypeptide comprises the sequence of SEQ ID NO: 2193.WSGR Docket No. 53676-759.601

[0007] In some embodiments, the IL-21 mutein polypeptide comprises an aromatic amino acid substitution of He at position 8 of SEQ ID NO: 2193.

[0008] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe or Trp.

[0009] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe.

[0010] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp.

[0011] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, or any combination thereof.

[0012] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu.

[0013] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Lys.

[0014] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu.

[0015] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe, an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Lys, an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu.

[0016] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5033.

[0017] In some embodiments, the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5033.

[0018] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193 with Thr, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193 with Gly, an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp, an amino acid substitution of Leu at position 123 of SEQ ID NO: 2193 with Thr, or any combination thereof.

[0019] In some embodiments, the IL-21 mutein polypeptide comprise an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, and an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp.WSGR Docket No. 53676-759.601

[0020] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5025.

[0021] In some embodiments, the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO:5025.

[0022] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe, and an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Lys.

[0023] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5026.

[0024] In some embodiments, the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO:5026.

[0025] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193 with Thr, and an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp.

[0026] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5027.

[0027] In some embodiments, the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO:5027.

[0028] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193 with Gly, and an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp.

[0029] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5029.

[0030] In some embodiments, the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO:5029.

[0031] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe, an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Lys, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu.

[0032] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5030.

[0033] In some embodiments, the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO:5030.WSGR Docket No. 53676-759.601

[0034] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193 with Thr, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193 with Gly, an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp, and an amino acid substitution of Leu at position 123 of SEQ ID NO: 2193 with Thr.

[0035] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5031.

[0036] In some embodiments, the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO:5031.

[0037] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp.

[0038] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5032.

[0039] In some embodiments, the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO:5032.

[0040] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193 with Thr, an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193 with Gly, an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp, and an amino acid substitution of Leu at position 123 of SEQ ID NO: 2193 with Thr.

[0041] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5034.

[0042] In some embodiments, the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5034.

[0043] In another aspect, provided herein is a multispecific molecule comprising:(i) a first domain that binds to one or more subunits of a T cell receptor complex; and(ii) a second domain comprising the IL-21 mutein polypeptide of the composition as described herein.

[0044] In another aspect, provided herein is a multispecific molecule comprising:(i) a first domain that binds to one or more subunits of a T cell receptor complex; andWSGR Docket No. 53676-759.601(ii) a second domain comprising a IL-21 mutein polypeptide, wherein the IL-21 mutein polypeptide comprises a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, or any combination thereof.

[0045] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu.

[0046] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5028.

[0047] In some embodiments, the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5028.

[0048] In another aspect, provided herein is a multispecific molecule comprising:(i) a first domain that binds to one or more subunits of a T cell receptor complex; and(ii) a second domain comprising a IL-21 mutein polypeptide, wherein the IL-21 mutein polypeptide comprises a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, and the IL-21 mutein polypeptide comprises an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, and the IL-21 mutein polypeptide comprises an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, or any combination thereof.

[0049] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, and the IL-21 mutein polypeptide comprises an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu.

[0050] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5035.

[0051] In some embodiments, the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5035.

[0052] In another aspect, provided herein is a multispecific molecule comprising:(i) a first domain that binds to one or more subunits of a T cell receptor complex; and(ii) a second domain comprising a fusion polypeptide comprising a IL-21 polypeptide sequence or a fragment thereof fused to an IL-4 sequence or a fragment thereof.

[0053] In some embodiments, the fusion polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5052 operatively linked to a sequence having at leastWSGR Docket No. 53676-759.60180% sequence identity to the sequence of SEQ ID NO: 5053 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5054.

[0054] In some embodiments, the fusion polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5036.

[0055] In some embodiments, the fusion polypeptide comprises the sequence of SEQ ID NO: 5052 operatively linked to the sequence of SEQ ID NO: 5053 operatively linked to the sequence of SEQ ID NO: 5054.

[0056] In some embodiments, the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5036.

[0057] In some embodiments, when the first domain binds to the one or more subunits of a T cell receptor complex, the first domain activates the one or more subunits of a T cell receptor complex.

[0058] In some embodiments, the one or more subunits of a T cell receptor complex express on a T cell in a T cell population.

[0059] In another aspect, provided herein is a multispecific molecule comprising:(i) a first domain that binds to a receptor on a T cell in a T cell population; and(ii) a second domain comprising the IL-21 mutein polypeptide of the composition as described herein, wherein the receptor on a T cell in a T cell population is not CD8.

[0060] In another aspect, provided herein is a multispecific molecule comprising:(i) a first domain that binds to a receptor on a T cell in a T cell population; and(ii) a second domain comprising a IL-21 mutein polypeptide, wherein the IL-21 mutein polypeptide comprises a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, and the IL-21 mutein polypeptide comprises an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, or any combination thereof, wherein the receptor on a T cell in a T cell population is not CD8.

[0061] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, and the IL-21 mutein polypeptide comprises an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu,

[0062] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5028.

[0063] In some embodiments, the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5028.

[0064] In another aspect, provided herein is a multispecific molecule comprising:(i) a first domain that binds to a receptor on a T cell in a T cell population; and(ii) a second domain comprising a IL-21 mutein polypeptide, wherein the IL-21 mutein polypeptide comprises a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, andWSGR Docket No. 53676-759.601 the IL-21 mutein polypeptide comprises an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, and the IL-21 mutein polypeptide comprises an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, or any combination thereof, wherein the receptor on a T cell in a T cell population is not CD8.

[0065] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, and the IL-21 mutein polypeptide comprises an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu.

[0066] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5035.

[0067] In some embodiments, the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO:5035.

[0068] In another aspect, provided herein is a multispecific molecule comprising:(i) a first domain that binds to a receptor on a T cell in a T cell population; and(ii) a second domain comprising a fusion polypeptide comprising a IL-21 polypeptide sequence or a fragment thereof fused to an IL-4 sequence or a fragment thereof, wherein the receptor on a T cell in a T cell population is not CD8.

[0069] In some embodiments, the fusion polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5052 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5053 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5054.

[0070] In some embodiments, the fusion polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5036.

[0071] In some embodiments, the fusion polypeptide comprises the sequence of SEQ ID NO: 5052 operatively linked to the sequence of SEQ ID NO: 5053 operatively linked to the sequence of SEQ ID NO: 5054.

[0072] In some embodiments, the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO:5036.

[0073] In some embodiments, when the first domain binds to the receptor on a T cell in a T cell population, the first domain activates the receptor on a T cell in a T cell population.

[0074] In some embodiments, the first domain binds to a T cell receptor alpha (TCRa) chain, a T cell receptor beta (TCR[3) chain, a T cell receptor gamma (TCRy) chain, a T cell receptor delta (TCR5) chain, a CD3 gamma (CD3y) chain, a CD3 delta (CD35) chain, a CD3 epsilon (CD3a) chain, a CD3 zeta (CD3Q chain, or any combination thereof.WSGR Docket No. 53676-759.601

[0075] In some embodiments, the first domain binds to a T cell receptor beta (TCRP) chain.

[0076] In some embodiments, the first domain binds to a T cell receptor beta variable (TCRJ3V) region.

[0077] In some embodiments, the first domain binds to a T cell receptor alpha (TCRa) chain.

[0078] In some embodiments, the first domain binds to a T cell receptor alpha variable (TCRaV) region.

[0079] In some embodiments, the first domain binds to a TCRJ3V region of TCRpV 1, TCR[3V2, TCRPV3, TCRPV4, TCRPV5, TCRPV6, TCRPV7, TCRPV8, TCRPV9, TCRpVIO, TCRpVl 1, TCRPV12, TCRPV19, TCRPV20, TCRPV21, TCRPV23, TCRPV24, TCRPV25, TCRPV26, TCRPV27, TCRPV28, TCRPV29, or TCRPV30.

[0080] In some embodiments, the first domain binds to a TCRpV region of TCRPV2, TCRPV4-1, TCRPV4-2, TCRPV5-1, TCRPV5-5, TCRPV5-6, TCRPV6, TCRPV6-5, TCRPV6-6, TCRPV6-9, TCRPV7-2, TCRPV7-3, TCRPV7-8, TCRPV7-9, TCRPV9, TCRpV10-l, TCRpV10-2, TCRpV10-3, TCRPV11-2, TCRPV12-3, TCRPV12-4, TCRPV12-5, TCRPV19, TCRPV20-1, TCRPV21, TCRPV24-1, TCRPV25-1, or TCRPV28.

[0081] In some embodiments, the first domain binds to a TCRpV region of TCRPV2, TCRPV3-1, TCRPV4-1, TCRPV4-2, TCRPV5-1, TCRPV5-4, TCRPV5-5, TCRPV5-6, TCRPV6-1, TCRPV6-5, TCRPV6-6, TCRPV7-3, TCRPV7-6, TCRPV7-8, TCRPV9, TCRpVl l-2, TCRPV19, TCRPV20-1, TCRPV24-1, TCRPV27, TCRPV28, TCRPV29-1, or TCRPV30.

[0082] In some embodiments, the first domain binds to a TCRpV region of TCRPV5, TCRPV6, TCRPVIO, TCRPV 12, or TCRPV20.

[0083] In some embodiments, the first domain comprises an antibody molecule or an antigen binding domain.

[0084] In some embodiments, the antibody molecule or the antigen binding domain comprises a scFv, a full-length antibody, a Fab, a F(ab')2, an Fv, a single chain Fv, a camelid antibody, a half arm antibody, a diabody, a bivalent antibody, a monovalent antibody, or a bispecific antibody.

[0085] In some embodiments, the antibody molecule or the antigen binding domain comprises a scFv, a single domain antibody, a camelid antibody, or a Fab.

[0086] In some embodiments, the antibody molecule or the antigen binding domain comprises a Fab.

[0087] In some embodiments, the antibody molecule or the antigen binding domain comprises a heavy chain variable region (VH) comprising a heavy chain complementarity determining region 1 (HC CDR1) sequence comprising any one of the HC CDR1 sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25, a heavy chain complementarity determining region 2 (HC CDR2) sequence comprising any one of the HC CDR2 sequences listed in Tablesl, 2, 10, 12, 13, 21, 22, 23, 24, or 25, and a heavy chain complementarity determining region 3 (HC CDR3) sequence of comprising any one of the HC CDR3 sequences listed in Tablesl, 2, 10, 12, 13, 21, 22, 23, 24, or 25.

[0088] In some embodiments, the antibody molecule or the antigen binding domain comprises a light chain variable region (VL) comprising a light chain complementarity determining region 1 (LC CDR1) sequence comprising any one of the LC CDR1 sequences listed in Tablesl, 2, 10, 12, 13, 21, 22, 23, 24, or 25, a light chain complementarity determining region 2 (LC CDR2) sequence comprising any one ofWSGR Docket No. 53676-759.601 the LC CDR2 sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25, and a light chain complementarity determining region 3 (LC CDR3) sequence of comprising any one of the LC CDR3 sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25.

[0089] In some embodiments, the antibody molecule or the antigen binding domain comprises:(i) a heavy chain variable region (VH) comprising a heavy chain complementarity determining region 1 (HC CDR1) sequence comprising any one of the HC CDR1 sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25, a heavy chain complementarity determining region 2 (HC CDR2) sequence comprising any one of the HC CDR2 sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25, and a heavy chain complementarity determining region 3 (HC CDR3) sequence of comprising any one of the HC CDR3 sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25.; and(ii) a light chain variable region (VL) comprising a light chain complementarity determining region 1 (LC CDR1) sequence comprising any one of the LC CDR1 sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25, a light chain complementarity determining region 2 (LC CDR2) sequence comprising any one of the LC CDR2 sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25, and a light chain complementarity determining region 3 (LC CDR3) sequence of comprising any one of the LC CDR3 sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25.

[0090] In some embodiments, the antibody molecule or the antigen binding domain comprises a VH comprising an amino acid sequence having at least 80% sequence identity to any one of the VH sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25.

[0091] In some embodiments, the antibody molecule or the antigen binding domain comprises a VL comprising an amino acid sequence having at least 80% sequence identity to any one of the VL sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25.

[0092] In some embodiments, the antibody molecule or the antigen binding domain comprises a VH comprising an amino acid sequence having at least 80% sequence identity to any one of the VH sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25; and a VL comprising an amino acid sequence having at least 80% sequence identity to any one of the VL sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25.

[0093] In some embodiments, the antibody molecule or the antigen binding domain comprises a VH comprising any one of the VH sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25.

[0094] In some embodiments, the antibody molecule or the antigen binding domain comprises a VL comprising any one of the VL sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25

[0095] In some embodiments, the antibody molecule or the antigen binding domain comprises a VH comprising any one of the VH sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25; and a VL comprising any one of the VL sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25.

[0096] In some embodiments, the antibody molecule or the antigen binding domain comprises a VH comprising a HC CDR1 comprising the sequence GHDFRLTYIH (SEQ ID NO: 3650), a HC CDR2 comprising the sequence RVSAGSGNVKYNEKFKG (SEQ ID NO: 3651), and a HC CDR3 comprising the sequence SYYSYDVLDY (SEQ ID NO: 47).WSGR Docket No. 53676-759.601

[0097] In some embodiments, the antibody molecule or the antigen binding domain comprises a VL comprising a LC CDR1 comprising the sequence KASQNVADRVV (SEQ ID NO: 3655), a LC CDR2 comprising the sequence SSSHRYK (SEQ ID NO: 3653), and a LC CDR3 comprising the sequence QQFKSYPLT (SEQ ID NO: 8).

[0098] In some embodiments, the antibody molecule or the antigen binding domain comprises:(i) a VH comprising a HC CDR1 comprising the sequence GHDFRLTYIH (SEQ ID NO: 3650), a HC CDR2 comprising the sequence RVSAGSGNVKYNEKFKG (SEQ ID NO: 3651), and a HC CDR3 comprising the sequence SYYSYDVLDY (SEQ ID NO: 5); and(ii) a VL comprising a LC CDR1 comprising the sequence KASQNVADRVV (SEQ ID NO: 3655), a LC CDR2 comprising the sequence SSSHRYK (SEQ ID NO: 3653), and a LC CDR3 comprising the sequence QQFKSYPLT (SEQ ID NO: 8).

[0099] In some embodiments, the antibody molecule or the antigen binding domain comprises a VH comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1346.

[0100] In some embodiments, the antibody molecule or the antigen binding domain comprises a VL comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1349.

[0101] In some embodiments, the antibody molecule or the antigen binding domain comprises a VH comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1346, and a VL comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1349.

[0102] In some embodiments, the antibody molecule or the antigen binding domain comprises a VH comprising the sequence of SEQ ID NO: 1346.

[0103] In some embodiments, the antibody molecule or the antigen binding domain comprises a VL comprising the sequence of SEQ ID NO: 1349.

[0104] In some embodiments, the antibody molecule or the antigen binding domain comprises a VH comprising the sequence of SEQ ID NO: 1346, and a VL comprising the sequence of SEQ ID NO: 1349.

[0105] In some embodiments, the antibody molecule or the antigen binding domain comprises a single chain Fv (scFv) comprising an amino acid sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 140, 153, 168, 183, or 195.

[0106] In some embodiments, the antibody molecule or the antigen binding domain comprises a scFv comprising the sequence of SEQ ID NO: 140, 153, 168, 183, or 195.

[0107] In some embodiments, the multispecific molecule comprises a first polypeptide chain and a second polypeptide chain; wherein the first polypeptide chain and the second polypeptide chain are non-contiguous; wherein the first polypeptide chain comprises a first member of a dimerization module and the second polypeptide chain comprises a second member of the dimerization module, wherein the first polypeptide chain and the second polypeptide chain form a complex via association of the first member of the dimerization module and the second member of the dimerization module; and wherein the dimerization module comprises an immunoglobulin constant domain.WSGR Docket No. 53676-759.601

[0108] In some embodiments, the molecule comprises the first polypeptide chain, the second polypeptide chain, and a third polypeptide chain, wherein the first polypeptide chain, the second polypeptide chain, and the third polypeptide chain are non-contiguous, and wherein:(i) the first polypeptide chain comprises a first portion of the first domain, wherein the first portion is operatively linked to the first member of a dimerization module,(ii) the second polypeptide chain comprises the second domain, wherein the second domain is operatively linked to the second member of the dimerization module, and(iii) the third polypeptide chain comprises a second portion of the first domain, wherein the first portion of the first domain and the second portion of the first domain are assembled and form the first domain.

[0109] In some embodiments, the first domain comprises an antibody molecule or an antigen binding domain, and the first portion of the first domain is a VH and the second portion of the first domain is a VL.

[0110] In some embodiments, the first domain comprises an antibody molecule or an antigen binding domain, and the first portion of the first domain is a VL and the second portion of the first domain is a VH.

[0111] In some embodiments, the first member of the dimerization module is a first Fc region, and the second member of the dimerization module is a second Fc region.

[0112] In some embodiments, the first polypeptide chain comprises the first domain operatively linked to the first Fc region, and the second polypeptide chain comprises the second domain operatively linked to the second Fc region.

[0113] In some embodiments, (i) the first Fc region comprises a mutation that decreases Fc receptor binding relative to a Fc region without the mutation;(ii) the second Fc region comprise a mutation that decreases Fc receptor binding relative to a Fc region without the mutation; or(iii) a combination thereof.

[0114] In some embodiments, the mutation that decreases Fc receptor binding is an N297A mutation according to EU Numbering in a heavy chain constant region.

[0115] In some embodiments, the first Fc region and the second Fc region comprise an Fc interface with one or more of: a knob-in-a hole, an electrostatic interaction, or a strand-exchange.

[0116] In some embodiments, the first Fc region is an engineered Fc region comprising a knob and the second Fc region is an engineered Fc region comprising a hole, or the first Fc region is an engineered Fc region comprising a hole and the second Fc region is an engineered Fc region comprising a knob.

[0117] In some embodiments, (A)(i) the first Fc region comprises:(a) Y349C mutation according to EU Numbering,(b) T366S mutation according to EU Numbering,(c) L368A mutation according to EU Numbering, andWSGR Docket No. 53676-759.601(d) Y407V mutation according to EU Numbering; and(ii) the second Fc region comprises:(a) S354C mutation according to EU Numbering, and(b) T366W mutation according to EU Numbering; or(B)(i) the first Fc region comprises:(a) S354C mutation according to EU Numbering, and(b) T366W mutation according to EU Numbering; and(ii) the second Fc region comprises:(a) Y349C mutation according to EU Numbering,(b) T366S mutation according to EU Numbering,(c) L368A mutation according to EU Numbering, and(d) Y407V mutation according to EU Numbering.

[0118] In some embodiments, the first Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5044 or the sequence of SEQ ID NO: 5045, and the second Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5045 or the sequence of SEQ ID NO: 5046.

[0119] In some embodiments, (i) the first Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5044, and the second Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5045;(ii) the first Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5045, and the second Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5046;(iii) the first Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5044, and the second Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5046; or(iv) the first Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5045, and the second Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5045.

[0120] In some embodiments, the first Fc region comprises the sequence of SEQ ID NO: 5044 or the sequence of SEQ ID NO: 5045, and the second Fc region comprises the sequence of SEQ ID NO: 5045 or the sequence of SEQ ID NO: 5046.

[0121] In some embodiments, (i) the first Fc region comprises the sequence of SEQ ID NO: 5044, and the second Fc region comprises the sequence of SEQ ID NO: 5045;(ii) the first Fc region comprises the sequence of SEQ ID NO: 5045, and the second Fc region comprises the sequence of SEQ ID NO: 5046;(iii) the first Fc region comprises the sequence of SEQ ID NO: 5044, and the second Fc region comprises the sequence of SEQ ID NO: 5046;WSGR Docket No. 53676-759.601(iv) the first Fc region comprises the sequence of SEQ ID NO: 5045, and the second Fc region comprises the sequence of SEQ ID NO: 5045.

[0122] In some embodiments, the first Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5048 or the sequence of SEQ ID NO: 5049, and the second Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5050 or the sequence of SEQ ID NO: 5051.

[0123] In some embodiments, (i) the first Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5048, and the second Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5050;(ii) the first Fc region comprises a sequence having at least 80 % sequence identity to the sequence of or the sequence of SEQ ID NO: 5049, and the second Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5051;(iii) the first Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5048, and the second Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5051; or(iv) the first Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5049, and the second Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5050.

[0124] In some embodiments, the first Fc region comprises the sequence of SEQ ID NO: 5048 or the sequence of SEQ ID NO: 5049, and the second Fc region comprises the sequence of SEQ ID NO: 5050 or the sequence of SEQ ID NO: 5051.

[0125] In some embodiments, (i) the first Fc region comprises the sequence of SEQ ID NO: 5048, and the second Fc region comprises the sequence of SEQ ID NO: 5050;(ii) the first Fc region comprises the sequence of SEQ ID NO: 5049, and the second Fc region comprises the sequence of SEQ ID NO: 5051(iii) the first Fc region comprises the sequence of SEQ ID NO: 5048, and the second Fc region comprises the sequence of SEQ ID NO: 5051; or(iv) the first Fc region comprises the sequence of SEQ ID NO: 5049, and the second Fc region comprises the sequence of SEQ ID NO: 5050.

[0126] In some embodiments, the multispecific molecule comprises a VL operatively linked to a light chain constant region or a fragment thereof.

[0127] In some embodiments, the light chain constant region or a fragment thereof comprises a kappa light chain constant region or a fragment thereof, or a lambda light chain constant region.

[0128] In some embodiments, the light chain constant region or a fragment thereof comprise a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 39 or SEQ ID NO: 3644.

[0129] In some embodiments, the light chain constant region or a fragment thereof comprise the sequence of SEQ ID NO: 39 or SEQ ID NO: 3644.

[0130] In some embodiments, the multispecific molecule comprises:WSGR Docket No. 53676-759.601(i) a first polypeptide chain comprising a VH of the first domain, wherein the first domain comprises an antibody molecule or an antigen binding domain that binds to a TCRpV region, and wherein the VH is operatively linked to a first Fc region;(ii) a second polypeptide chain comprising the second domain comprising the IL-21 mutein polypeptide, wherein the IL-21 mutein polypeptide comprises a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, and the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe, an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Lys, an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu; and wherein the second domain is operatively linked to a second Fc region; and(iii) a third polypeptide chain comprising a VL of the first domain, wherein the VL is operatively linked to a light chain constant region; wherein the VH of the first domain and the VL of the first domain are assembled and form the first domain.

[0131] In some embodiments, the second domain is operatively linked to the second Fc region via a linker sequence.

[0132] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1346 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5044;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5033 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5046; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1349 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 3644.

[0133] In some embodiments, the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5033 is operatively linked to the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5046 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

[0134] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 1346 operatively linked to the sequence of SEQ ID NO: 5044;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5033 operatively linked to the sequence of SEQ ID NO: 5046; andWSGR Docket No. 53676-759.601(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 1349 operatively linked to the sequence of SEQ ID NO: 3644.

[0135] In some embodiments, the sequence of SEQ ID NO: 5033 is operatively linked to the sequence of SEQ ID NO: 5046 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

[0136] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5055;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5060; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5059.

[0137] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 5055;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5060; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 5059.

[0138] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1346 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5048;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5033 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5050; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1349 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 3644.

[0139] In some embodiments, the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5033 is operatively linked to the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5050 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

[0140] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 1346 operatively linked to the sequence of SEQ ID NO: 5048;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5033 operatively linked to the sequence of SEQ ID NO: 5050; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 1349 operatively linked to the sequence of SEQ ID NO: 3644.

[0141] In some embodiments, the sequence of SEQ ID NO: 5033 is operatively linked to the sequence of SEQ ID NO: 5050 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

[0142] In some embodiments, the multispecific molecule comprises:WSGR Docket No. 53676-759.601(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5057;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5062; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5059.

[0143] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 5057;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5062; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 5059.

[0144] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising a VH of the first domain, wherein the first domain comprises an antibody molecule or an antigen binding domain that binds to a TCR[3V region, and wherein the VH is operatively linked to a first Fc region;(ii) a second polypeptide chain comprising the second domain comprising the IL-21 mutein polypeptide, wherein the IL-21 mutein polypeptide comprises a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, and the IL-21 mutein polypeptide comprises an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu; and wherein the second domain is operatively linked to a second Fc region; and(iii) a third polypeptide chain comprising a VL of the first domain, wherein the VL is operatively linked to a light chain constant region; wherein the VH of the first domain and the VL of the first domain are assembled and form the first domain.

[0145] In some embodiments, the second domain is operatively linked to the second Fc region via a linker sequence.

[0146] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1346 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5044;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5028 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5046; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1349 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 3644.WSGR Docket No. 53676-759.601

[0147] In some embodiments, the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5028 is operatively linked to the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5046 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

[0148] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 1346 operatively linked to the sequence of SEQ ID NO: 5044;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5028 operatively linked to the sequence of SEQ ID NO: 5046; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 1349 operatively linked to the sequence of SEQ ID NO: 3644.

[0149] In some embodiments, the sequence of SEQ ID NO: 5028 is operatively linked to the sequence of SEQ ID NO: 5046 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

[0150] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5055;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5064; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5059.

[0151] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 5055;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5064; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 5059.

[0152] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1346 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5048;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5028 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5050; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1349 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 3644.

[0153] In some embodiments, the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5028 is operatively linked to the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5050 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

[0154] In some embodiments, the multispecific molecule comprises:WSGR Docket No. 53676-759.601(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 1346 operatively linked to the sequence of SEQ ID NO: 5048;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5028 operatively linked to the sequence of SEQ ID NO: 5050; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 1349 operatively linked to the sequence of SEQ ID NO: 3644.

[0155] In some embodiments, the sequence of SEQ ID NO: 5028 is operatively linked to the sequence of SEQ ID NO: 5050 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

[0156] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5057;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of 5066; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5059.

[0157] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 5057;(ii) a second polypeptide chain comprising the sequence of 5066; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 5059.

[0158] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising a VH of the first domain, wherein the first domain comprises an antibody molecule or an antigen binding domain that binds to a TCR[3V region, and wherein the VH is operatively linked to a first Fc region;(ii) a second polypeptide chain comprising the second domain comprising the IL-21 mutein polypeptide, wherein the IL-21 mutein polypeptide comprises a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, and the IL-21 mutein polypeptide comprises an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu; and wherein the second domain is operatively linked to a second Fc region; and(iii) a third polypeptide chain comprising a VL of the first domain, wherein the VL is operatively linked to a light chain constant region; wherein the VH of the first domain and the VL of the first domain are assembled and form the first domain.

[0159] In some embodiments, the second domain is operatively linked to the second Fc region via a linker sequence.

[0160] In some embodiments, the multispecific molecule comprises:WSGR Docket No. 53676-759.601(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1346 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5044;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5035 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5046; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1349 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 3644.

[0161] In some embodiments, the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5035 is operatively linked to the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5046 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

[0162] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 1346 operatively linked to the sequence of SEQ ID NO: 5044;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5035 operatively linked to the sequence of SEQ ID NO: 5046; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 1349 operatively linked to the sequence of SEQ ID NO: 3644.

[0163] In some embodiments, the sequence of SEQ ID NO: 5035 is operatively linked to the sequence of SEQ ID NO: 5046 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

[0164] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5055;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5068; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5059.

[0165] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 5055;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5068; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 5059.

[0166] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1346 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5048;WSGR Docket No. 53676-759.601(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5035 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5050; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1349 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 3644.

[0167] In some embodiments, the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5035 is operatively linked to the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5050 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

[0168] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 1346 operatively linked to the sequence of SEQ ID NO: 5048;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5035 operatively linked to the sequence of SEQ ID NO: 5050; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 1349 operatively linked to the sequence of SEQ ID NO: 3644.

[0169] In some embodiments, the sequence of SEQ ID NO: 5035 is operatively linked to the sequence of SEQ ID NO: 5050 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

[0170] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5057;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of 5070; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5059.

[0171] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 5057;(ii) a second polypeptide chain comprising the sequence of 5070; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 5059.

[0172] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising a VH of the first domain, wherein the first domain comprises an antibody molecule or an antigen binding domain that binds to a TCR[3V region, and wherein the VH is operatively linked to a first Fc region;(ii) a second polypeptide chain comprising the second domain comprising the IL-21 mutein polypeptide, wherein the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5036; and wherein the second domain is operatively linked to a second Fc region; andWSGR Docket No. 53676-759.601(iii) a third polypeptide chain comprising a VL of the first domain, wherein the VL is operatively linked to a light chain constant region; wherein the VH of the first domain and the VL of the first domain are assembled and form the first domain.

[0173] In some embodiments, the second domain is operatively linked to the second Fc region via a linker sequence.

[0174] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1346 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5044;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5036 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5046; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1349 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 3644.

[0175] In some embodiments, the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5036 is operatively linked to the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5046 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

[0176] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 1346 operatively linked to the sequence of SEQ ID NO: 5044;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5036 operatively linked to the sequence of SEQ ID NO: 5046; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 1349 operatively linked to the sequence of SEQ ID NO: 3644.

[0177] In some embodiments, the sequence of SEQ ID NO: 5036 is operatively linked to the sequence of SEQ ID NO: 5046 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

[0178] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5055;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5072; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5059.

[0179] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 5055;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5072; andWSGR Docket No. 53676-759.601(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 5059.

[0180] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1346 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5048;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5036 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5050; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1349 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 3644.

[0181] In some embodiments, the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5036 is operatively linked to the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5050 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

[0182] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 1346 operatively linked to the sequence of SEQ ID NO: 5048;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5036 operatively linked to the sequence of SEQ ID NO: 5050; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 1349 operatively linked to the sequence of SEQ ID NO: 3644.

[0183] In some embodiments, the sequence of SEQ ID NO: 5036 is operatively linked to the sequence of SEQ ID NO: 5050 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

[0184] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5057;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5074; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5059.

[0185] In some embodiments, the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 5057;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5074; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 5059.

[0186] In some embodiments, the multispecific molecule further comprises a tumor-targeting moiety that binds to a cancer antigen present on a cancer.WSGR Docket No. 53676-759.601

[0187] In some embodiments, the tumor-targeting moiety comprises an antibody molecule that binds to a cancer antigen, a receptor or receptor fragment or variant thereof that binds to a cancer antigen, a ligand or functional fragment or variant thereof that binds to a cancer antigen, or any combination thereof.

[0188] In some embodiments, the cancer antigen is a tumor antigen, a stromal antigen, or a hematological antigen.

[0189] In some embodiments, the cancer antigen is selected from the group consisting of: BCMA, FcRH5, CD19, CD20, CD22, CD30, CD33, CD38, CD3, CD47, CD99, CD123, CLEC12, CD179A, SLAMF7, PDL1, gangloside 2 (GD2), prostate stem cell antigen (PSCA), prostate specific membrane antigen (PSMA), prostate-specific antigen (PSA), carcinoembryonic antigen (CEA), Ron Kinase, c-Met, Immature laminin receptor, TAG-72, BING-4, Calcium -activated chloride channel 2, Cyclin-Bl, 9D7, Ep-CAM, EphA3, Her2 / neu, Telomerase, SAP-1, Survivin, NY-ESO-l / LAGE-1, PRAME, SSX-2, Melan-A / MART-1, Gpl00 / pmell7, Tyrosinase, MC1R, b-catenin, BRCA1 / 2, CDK4, CML66, Fibronectin, p53, Ras, TGF-B receptor, AFP, ETA, MAGE, CA-125, BAGE, GAGE, CDC27, actinin-4, TRPl / gp75, TRP2, WT1, Epidermal growth factor receptor (EGFR), MART-2, MUC1, MUC2, MUM1, MUM2, MUM3, NA88-1, NPM, OA1, OGT, RCC, RU11, RU12, SAGE, TRG, TSTA, Folate receptor alpha, Ll-CAM, CAIX, gpA33, GD3, GM2, VEGFR, an Integrin, a carbohydrate, IGF1R, TRAILR1, TRAILR2, RANKL, FAP, TGF-beta, hyaluronic acid, collagen, tenascin C, and tenascin W.

[0190] In some embodiments, the cancer is a hematological cancer, a solid tumor, a metastatic cancer, a soft tissue tumor, or any combination thereof.

[0191] In some embodiments, the cancer is a solid tumor selected from the group consisting of colon cancer, pancreatic cancer, breast cancer, colorectal cancer, lung cancer, skin cancer, ovarian cancer, liver cancer, renal cancer, melanoma, prostate cancer, rectal cancer, cervical cancer, or any combination thereof.

[0192] In some embodiments, the cancer is a solid tumor selected from the group consisting of an anti- PD1 therapy resistant solid cancer, an HPV-positive solid cancer, a cancer with a high tumor mutation burden, or any combination thereof.

[0193] In some embodiments, the cancer is a hematological cancer comprising a B-cell malignancy or a T cell malignancy.

[0194] In some embodiments, the B-cell malignancy or the T cell malignancy is selected from the group consisting of Hodgkin’s lymphoma, Non-Hodgkin’s lymphoma, acute myeloid leukemia (AML), chronic myeloid leukemia, myelodysplastic syndrome, multiple myeloma, and acute lymphocytic leukemia.

[0195] In some embodiments, the Non-Hodgkin's lymphoma is selected from the group consisting of B cell lymphoma, diffuse large B cell lymphoma, follicular lymphoma, chronic lymphocytic leukemia, mantle cell lymphoma, marginal zone B-cell lymphoma, Burkitt lymphoma, lymphoplasmacytic lymphoma, and hairy cell leukemia.

[0196] In some embodiments, the multispecific molecule further comprises an immune cell engager.

[0197] In some embodiments, the immune cell engager is an NK cell engager, a T cell engager, a B cell engager, a dendritic cell engager, or a macrophage cell engager.WSGR Docket No. 53676-759.601

[0198] In some embodiments, when contacted to the T cell population, the multispecific molecule redirects the T cell to a target cell, expands the T cell, and / or activates the T cell.

[0199] In some embodiments, the target cell is a cancer cell or T cells in the T cell population. In some embodiments, the T cell expansion occurs in vivo.

[0200] In some embodiments, the T cell expansion occurs ex vivo.

[0201] In some embodiments, when contacted to the T cell population, the multispecific molecule promotes T cells of the T cell population to kill cancer cells. In some embodiments, the T cell expansion occurs ex vivo. In some embodiment, the T cells comprise NK-T cells. In some embodiment, the T cells comprise CD4+ T cells. In some embodiment, the T cells comprise CD8+ T cells. In some embodiment, the T cells comprise CD25+ T cells. In some embodiment, the T cells comprise TCRVP+ T cells. In some embodiment, when contacted to the T cell population, the multispecific molecule promotes production of Granzyme B (GzB) as compared to a T cell population not contacted with the multispecific molecule. In some embodiment, when contacted to the T cell population, the multispecific molecule promotes production of one or more cytokines as compared to a T cell population not contacted with the multispecific molecule. In some embodiment, the one or more cytokines comprises interferon gamma (IFNy), interleukin- 1 beta (IL-ip), interleukin-6 (IL-6), interleukin- 10 (IL- 10), tumor necrosis factor alpha (TNF-a), or a combination thereof.

[0202] In another aspect, provided herein is a composition comprising the multispecific molecule as described herein.

[0203] In another aspect, provided herein is a recombinant polynucleotide comprising a sequence encoding the IL-21 mutein polypeptide of the composition as described herein or the multispecific molecule as described herein.

[0204] In another aspect, provided herein is a vector comprising the recombinant polynucleotide as described herein.

[0205] In another aspect, provided herein is a cell comprising the recombinant polynucleotide as described herein or the vector as described herein.

[0206] In another aspect, provided herein is a method of making the multispecific molecule as described herein, comprising culturing a host cell comprising a recombinant polynucleotide comprising a sequence encoding the multispecific molecule or a vector comprising the recombinant polynucleotide under conditions suitable for gene expression and / or homo- or heterodimerization.

[0207] In another aspect, provided herein is a pharmaceutical composition comprising the IL-21 mutein polypeptide of the composition as described herein, the multispecific molecule as described herein, or the composition as described herein, and a pharmaceutically acceptable carrier, excipient, or diluent.

[0208] In another aspect, provided herein is a method of treating cancer in a subject in need thereof comprising: administering a therapeutically effective amount of the multispecific molecule as described herein, the composition as described herein, or the pharmaceutical composition as described herein to the subject, thereby treating the cancer in the subject.WSGR Docket No. 53676-759.601

[0209] In another aspect, provided herein is use of the multispecific molecule as described herein, the composition as described herein, or the pharmaceutical composition as described herein in treating cancer in a subject in need thereof, wherein the multispecific molecule, the composition, or the pharmaceutical composition is formulated for administration in therapeutically effective amount to treat cancer in the subject.

[0210] In some embodiments, the subject is human.

[0211] In some embodiments, the cancer is a solid tumor, a hematological cancer, a metastatic cancer, a soft tissue tumor, or a combination thereof.

[0212] In some embodiments, the cancer is a solid tumor selected from the group consisting of colon cancer, pancreatic cancer, breast cancer, colorectal cancer, lung cancer, skin cancer, ovarian cancer, liver cancer, renal cancer, melanoma, prostate cancer, rectal cancer, cervical cancer, or any combination thereof.

[0213] In some embodiments, the cancer is a solid tumor selected from the group consisting of an anti- PD1 therapy resistant solid cancer, an HPV-positive solid cancer, a cancer with a high tumor mutation burden, or any combination thereof.

[0214] In some embodiments, the cancer is a hematological cancer comprising a B-cell malignancy or a T cell malignancy.

[0215] In some embodiments, the B-cell malignancy or the T cell malignancy is selected from the group consisting of Hodgkin’s lymphoma, Non-Hodgkin’s lymphoma, acute myeloid leukemia (AML), chronic myeloid leukemia, myelodysplastic syndrome, multiple myeloma, and acute lymphocytic leukemia.

[0216] In some embodiments, the Non-Hodgkin's lymphoma is selected from the group consisting of B cell lymphoma, diffuse large B cell lymphoma, follicular lymphoma, chronic lymphocytic leukemia, mantle cell lymphoma, marginal zone B-cell lymphoma, Burkitt lymphoma, lymphoplasmacytic lymphoma, and hairy cell leukemia.

[0217] In some embodiments, before administration of the composition, a sample from the subject has an increased level or activity of one or more TCR[3V subfamilies relative to a sample from a subject who does not have a cancer.

[0218] In some embodiments, the method further comprises administering the multispecific molecule, the composition, or the pharmaceutical composition in combination with an immune checkpoint inhibitor.

[0219] In some embodiments, the multispecific molecule, the composition, or the pharmaceutical composition is formulated to be used in combination with an immune checkpoint inhibitor.

[0220] In some embodiments, the immune checkpoint inhibitor is a PD-1 inhibitor or a PD-L1 inhibitor.

[0221] In some embodiments, the immune checkpoint inhibitor is a PD-1 inhibitor selected from the group consisting ofNivolumab, Pembrolizumab, Pidilizumab, AMP 514, immunoadhesin, and AMP- 224.

[0222] In some embodiments, the immune checkpoint inhibitor is a PD-L1 inhibitor selected from the group consisting of MPDL3280A, MEDI-4736, MSB-0010718C, MSB0010718C, and YW243.55.S70.WSGR Docket No. 53676-759.601

[0223] In some embodiments, the multispecific molecule is not immobilized to a solid-phase.

[0224] In some embodiments, the multispecific molecule is immobilized to a solid-phase.

[0225] In another aspect, provided herein is a method of expanding and / or activating T cells that expresses a T cell receptor (TCR) comprising a T cell receptor beta (TCR[3) comprising a T cell receptor beta variable region (TCRJ3V) in a T cell population comprising: contacting the T cell population with the multispecific molecule as described herein, the composition as described herein, or the pharmaceutical composition as described herein in an effective amount, thereby expanding and / or activating the T cells in the T cell population.

[0226] In another aspect, provided herein is use of the multispecific molecule as described herein, the composition as described herein, or the pharmaceutical composition as described herein for expanding and / or activating T cells that expresses a T cell receptor (TCR) comprising a T cell receptor beta (TCR[3) comprising a T cell receptor beta variable region (TCRJ3V) in a T cell population by contacting the T cell population with the multispecific molecule, the composition, or the pharmaceutical composition in an effective amount, thereby expanding and / or activating the T cells in the T cell population.

[0227] In some embodiments, the expansion and / or activation is selective expansion and / or activation of a subset of T cells that express a TCR comprising a TCR[3 that comprises a TCRJ3V region subfamily member to which the first domain binds in the T cell population.

[0228] In some embodiments, the expansion and / or activation occurs in vivo.

[0229] In some embodiments, the expansion and / or activation occurs ex vivo.

[0230] In some embodiments, the T cell population is a population of T cells in a biological sample from a subject.

[0231] In some embodiments, the biological sample comprises a blood sample, a biopsy sample, or a bone marrow sample.

[0232] In some embodiments, the biological sample comprises a blood sample comprising a peripheral blood sample.

[0233] In some embodiments, the biological sample comprises a biopsy sample comprising a tumor biopsy sample.

[0234] In some embodiments, when contacted the T cell population, the multispecific molecule promotes T cells of the T cell population to kill cancer cells.

[0235] In some embodiments, the multispecific molecule is not immobilized to a solid-phase.

[0236] In some embodiments, the multispecific molecule is immobilized to a solid-phase.

[0237] In another aspect, provided herein is a method of preparing an IL-21 mutein polypeptide comprising: preparing an IL-21 mutein polypeptide comprising a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, and an aromatic amino acid substitution of He at position 8 of SEQ ID NO: 2193, wherein when expressed in a cell, the IL-21 mutein polypeptide is less susceptible to proteolytic cleavage compared to an IL-21 wild-type or variant polypeptide without the aromatic amino acid substitution ofWSGR Docket No. 53676-759.601He at position 8 of SEQ ID NO: 2193 when expressed in a cell, thereby enhancing and / or prolong the activity of the IL-21 mutein polypeptide relative to the IL-21 wild-type or variant polypeptide.

[0238] In another aspect, provided herein is a method of enhancing and / or prolong the activity of an IL- 21 mutein comprising: introducing an aromatic amino acid substitution of He at position 8 of SEQ ID NO: 2193 to an IL-21 mutein polypeptide, wherein when expressed in a cell, the IL-21 mutein polypeptide is less susceptible to proteolytic cleavage compared to an IL-21 wild-type or variant polypeptide without the aromatic amino acid substitution of He at position 8 of SEQ ID NO: 2193 when expressed in a cell, thereby enhancing and / or prolong the activity of the IL-21 mutein polypeptide relative to the IL-21 wild-type or variant polypeptide.

[0239] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193.

[0240] In some embodiments, the IL-21 wild-type polypeptide comprises the sequence of SEQ ID NO: 2193.

[0241] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe or Trp.

[0242] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe.

[0243] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp.

[0244] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, or any combination thereof.

[0245] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu.

[0246] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Lys.

[0247] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu.

[0248] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe, an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Lys, an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu.

[0249] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5033.WSGR Docket No. 53676-759.601

[0250] In some embodiments, the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5033.

[0251] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193 with Thr, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193 with Gly, an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp, an amino acid substitution of Leu at position 123 of SEQ ID NO: 2193 with Thr, or any combination thereof.

[0252] In some embodiments, the IL-21 mutein polypeptide comprise an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, and an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp.

[0253] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5025.

[0254] In some embodiments, the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO:5025.

[0255] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe, and an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Lys.

[0256] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5026.

[0257] In some embodiments, the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO:5026.

[0258] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193 with Thr, and an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp.

[0259] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5027.

[0260] In some embodiments, the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO:5027.

[0261] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193 with Gly, and an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp.

[0262] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5029.

[0263] In some embodiments, the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5029.WSGR Docket No. 53676-759.601

[0264] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe, an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Lys, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu.

[0265] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5030.

[0266] In some embodiments, the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO:5030.

[0267] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193 with Thr, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193 with Gly, an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp, and an amino acid substitution of Leu at position 123 of SEQ ID NO: 2193 with Thr.

[0268] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5031.

[0269] In some embodiments, the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO:5031.

[0270] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp.

[0271] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5032.

[0272] In some embodiments, the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO:5032.

[0273] In some embodiments, the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193 with Thr, an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193 with Gly, an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp, and an amino acid substitution of Leu at position 123 of SEQ ID NO: 2193 with Thr.WSGR Docket No. 53676-759.601

[0274] In some embodiments, the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5034.

[0275] In some embodiments, the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5034.INCORPORATION BY REFERENCE

[0276] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference.BRIEF DESCRIPTION OF THE DRAWINGS

[0277] The novel features of the disclosure are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present disclosure will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the disclosure are utilized, and the accompanying drawings of which:

[0278] FIGs. 1A-1T depict exemplary embodiments of multifunctional or multispecific molecules as described herein. FIGs. 1A, IB and 1C depict exemplary embodiments of multifunctional or multispecific molecules containing multiple, e.g., two, molecules of interleukin-21 (IL-21), IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof linked to an antibody molecule that binds to a T cell receptor beta variable region (TCRJ3V) (“anti-TCRpV antibody molecule”). FIGs. ID, IE and IF depict exemplary embodiments of multifunctional or multispecific molecules containing a single molecule of IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof linked to an anti-TCRpV antibody molecule. FIGs. 1G, 1H, II, and 1J depict exemplary embodiments of multifunctional or multispecific molecules containing IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof linked to a first dimerization module. FIGs. IK, IL and IM depict exemplary embodiments of multifunctional or multispecific molecules containing an exemplary dimerization module, e.g., an Fc region comprising a N297A mutation, and multiple, e.g., two, molecules of IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof linked to an anti-TCRpV antibody molecule. FIGs. IN, IO and IP depict exemplary embodiments of multifunctional or multispecific molecules containing an exemplary dimerization module, e.g., an Fc region comprising a N297A mutation (Knob-in-hole), and a single molecule of IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof. FIGs. IQ, 1R, IS and IT depict exemplary embodiments of multifunctional or multispecific molecules containing an exemplary dimerization module, e.g., an Fc region comprising a N297A mutation (Knob-in-hole), and IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof linked to the exemplary dimerization module. The “IL21” as shown in FIGs. 1A-1T is IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein. In some embodiments, the multifunctional or multispecific molecules as provided herein further comprises a tumor-associated antigen binding moiety. In some embodiments, the multifunctional or multispecific molecules as provided herein comprises a tumor-associated antigen binding moiety, a molecule that bindsWSGR Docket No. 53676-759.601 to a co-stimulatory receptor of a T cell, and a TCRpV-binding moiety. In some embodiments, the multifunctional or multispecific molecules as provided herein comprises a tumor-associated antigen binding moiety and a TCRpV-binding moiety, instead of two TCRpV-binding moieties, and a molecule that binds to a co-stimulatory receptor of a T cell. In some embodiments, one of anti -TCRpV-binding moieties as shown in FIGs. 1A-1F, II- IP, and 1S-1 IT is replaced with a tumor-associated antigen binding moiety. In some embodiments, the molecule that binds to a co-stimulatory receptor of a T cell comprises at least one cytokine molecule or a functional fragment or functional variant thereof, for example, IL-21 , IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein. In some embodiments, the molecule that binds to a co-stimulatory receptor of a T cell comprises an antibody molecule, an antigen binding domain, a ligand, an extracellular domain of a receptor, or any combination thereof. In some embodiments, the molecule that binds to a co-stimulatory receptor of a T cell binds to CD2, 4- IBB, CD27, CD28, or any combination thereof.

[0279] FIGs. 2A and 2B shows the alignment of the Antibody A source mouse VH and VL framework 1, CDR 1, framework 2, CDR 2, framework 3, CDR3, and framework 4 regions with their respective humanized sequences. Kabat CDRs are shown in bold, Chothia CDRs are shown in italics, and combined CDRs are shown in boxes. The framework positions that were back mutated are double underlined. FIG. 2A shows VH sequences for murine Antibody A (SEQ ID NO: 1) and humanized Antibody A-H (SEQ ID NO: 9). FIG. 2B shows VL sequences for murine Antibody A (SEQ ID NO: 2) and humanized Antibody A-H (SEQ ID NO: 10 and SEQ ID NO: 11).

[0280] FIGs. 3A-3C shows the alignment of the Antibody B source mouse VH and VL framework 1, CDR 1, framework 2, CDR 2, framework 3, CDR3, and framework 4 regions with their respective humanized sequences. Kabat CDRs are shown in bold, Chothia CDRs are shown in italics, and combined CDRs are shown in boxes. The framework positions that were back mutated are double underlined. FIG. 3A shows the VH sequence for murine Antibody B (SEQ ID NO: 15) and humanized VH sequences B- H.1A to B-H.1C (SEQ ID NOs: 23-25). FIG. 3B shows the VL sequence for murine Antibody B (SEQ ID NO: 16) and humanized VL sequences B-H.1D to B-H.1H (SEQ ID NOs: 26-30). FIG. 3C shows the VL sequence for murine Antibody B (SEQ ID NO: 16) and humanized VL sequences B-H. ID to B-H. 1H (SEQ ID NOs: 26-30), continued from FIG. 3B.

[0281] FIG. 4 depicts the phylogenetic tree of TCRBV gene family and subfamilies with corresponding antibodies mapped. Subfamily identities are as follows: Subfamily A: TCRp V6; Subfamily B: TCRp V10; Subfamily C: TCRp V12; Subfamily D: TCRp V5; Subfamily E: TCRp V7; Subfamily F: TCRp VI 1; Subfamily G: TCRp V14; Subfamily H: TCRp V16; Subfamily LTCRp V18; Subfamily J:TCRp V9; Subfamily K: TCRp V13; Subfamily L: TCRp V4; Subfamily M:TCRp V3; Subfamily N:TCRp V2; Subfamily O:TCRp V15; Subfamily P: TCRp V30; Subfamily Q: TCRp V19; Subfamily R:TCRp V27; Subfamily S:TCRp V28; Subfamily T: TCRp V24; Subfamily U: TCRp V20; Subfamily V: TCRp V25; and Subfamily W:TCRP V29 subfamily. Subfamily members are described in detail herein in the Section titled “TCR beta V (TCRpV)”.WSGR Docket No. 53676-759.601

[0282] FIGs. 5A and 5B show the structure and sequence of eight TCRpV proteins from seven different subfamilies: TCR[3V6 subfamily (TCR[3V6-5 and TCR[3V6-4 are shown), TCRPV28 subfamily, TCRJ3V19 subfamily, TCRJ3V9 subfamily, TCRJ3V5 subfamily, TCRJ3V20 subfamily and TCRJ3V12 subfamily. FIG. 5A shows the structural alignment of the different TCRJ3V proteins. The circled area represents the outward facing region comprising the proposed binding site for the anti -TCRpV antibodies as described herein. FIG. 5B shows the amino acid sequence alignment of the proteins shown in FIG. 5A (SEQ ID NOS 3449-3456, respectively, in order of appearance). The various TCRpV proteins (from 7 different TCRpV subfamilies) have diverse sequences but share a conserved (similar) structure and function.

[0283] FIG. 6 shows the relative representations of all TCR beta V segment 6-5 variants (TRBV6-5 gene) (bottom left), and all TCR beta V segments and variants excluding 6-5 (bottom right), and all TCR beta V segments and variants excluding 6-5 (bottom right). The data show that the anti-TCRVp antibody stimulation does not induce proliferation of specific T cell clones within the TRBV6-5 positive population, as the relative difference in clonal representation in that population is comparable to the TRBV6-5 negative population as well as total TRAV usage.

[0284] FIG. 7 shows a graphical representation of the relation of sequences between different TCRVB clonotype subfamilies.

[0285] FIG. 8 is a schematic of the experimental design for the pharmacokinetic (PK) profile and dosing strategy of the multifunctional or multispecific polypeptide molecule as described herein.

[0286] FIGs. 9A, 9B, and 9C show Table 9, which depicts alignment of TCRBV amino acid sequences (SEQ ID NOS 3457-3516, 3669-3673, 3522, 3674-3675, 3525, 3676-3687, 3538, 3688-3698, 3550-3639 and 3699-3790, respectively, in order of appearance). The alignment of TCRBV amino acid sequences in Table 9 underscores the diversity of TCR sequences. In particular, the TRBV sequences from different subfamilies are considerably different from each other.

[0287] FIG. 10 shows alignment of affinity matured humanized Antibody A-H VL sequences (SEQ ID NOS: 3377-3389, respectively, in order of appearance).

[0288] FIGs. 11A, 11B, and 11C show alignment of affinity matured humanized Antibody A-H VH sequences (SEQ ID NOS: 3390-3436, respectively, in order of appearance).

[0289] FIG. 12A shows an exemplary embodiment of multifunctional or multispecific molecules comprising a TCRpV-binding moiety and a cytokine polypeptide, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein. FIG. 12B shows an exemplary embodiment of multifunctional or multispecific molecules comprising a TCRpV-binding moiety and a cytokine polypeptide, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein. FIGs. 12C, 12D, 12E, and 12F show exemplary embodiments of multifunctional or multispecific molecules comprising a first TCRpV-binding moiety, a second TCRpV-binding moiety, and two cytokine polypeptides, i.e., two of IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein. In embodiments, the cytokine polypeptide further comprises a cytokine receptor. In some embodiments, the cytokineWSGR Docket No. 53676-759.601 polypeptide comprises a cytokine dimer. The ’’cytokine” as shown in FIGs. 12B-12F represents at least one cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL- 21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein, which is an exemplary embodiment of the molecule that binds to a co-stimulatory receptor of a T cell as described herein. In some embodiments, the multifunctional or multispecific molecules as provided herein further comprises a tumor-associated antigen binding moiety. In some embodiments, the multifunctional or multispecific molecules as provided herein comprises a tumor-associated antigen binding moiety, a molecule that binds to a co-stimulatory receptor of a T cell, and a TCRpV-binding moiety. In some embodiments, the multifunctional or multispecific molecules as provided herein comprises a tumor-associated antigen binding moiety and a TCRpV-binding moiety, instead of two TCRpV-binding moieties, and a molecule that binds to a co-stimulatory receptor of a T cell. In some embodiments, one of anti-TCRpV-binding moieties as shown in FIGs. 12C-12F is replaced with a tumor-associated antigen binding moiety. In some embodiments, the molecule that binds to a co- stimulatory receptor of a T cell comprises at least one cytokine molecule or a functional fragment or functional variant thereof, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein. In some embodiments, the molecule that binds to a co-stimulatory receptor of a T cell comprises an antibody molecule, an antigen binding domain, a ligand, an extracellular domain of a receptor, or any combination thereof. In some embodiments, the molecule that binds to a co-stimulatory receptor of a T cell binds to CD2, 4-1BB, CD27, CD28, or any combination thereof.

[0290] FIG. 13 shows in vitro TCR sequencing. PBMCs were incubated with lOOnM of BKM0186 for 5 days and T cells were sequenced for TCR P chain V (TRBV) genes. Compared to unstimulated T cells (grey), BKM0186 selectively expanded T cells bearing TRBV6-1 , TRBV6-2, TRBV6-3, TRBV6-5, and TRBV10-3.

[0291] FIG. 14 shows the experimental design for the tumor rechallenge study. Cured EMT6 tumor bearing mice were rechallenged with EMT6 tumor cells in one flank and CT26 tumor cells in another flank and monitored for tumor growth for 28 days.

[0292] FIGs. 15A and 15B show exemplary embodiments of multifunctional or multispecific molecules comprising a TCRpV-binding moiety and a cytokine molecule (e.g., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof) as described herein. FIGs. 15C-15T show exemplary embodiments of multifunctional or multispecific molecules, e.g., exemplary multifunctional or multispecific molecules comprising a tumor-associated antigen binding moiety, a TCRpV-binding moiety, and at least one cytokine molecule or a functional fragment or functional variant thereof, i.e., IL- 21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein, which is an exemplary embodiment of the molecule that binds to a co-stimulatory receptor of a T cell as described herein, as described herein. In some embodiments, a tumor-associated antigen binding moiety and / or a TCRpV-binding moiety are antibody, an antigen binding fragment thereof, an antibody fragment, or antigen binding domain. In some embodiments, an antigen binding fragment, an antibodyWSGR Docket No. 53676-759.601 fragment or antigen binding domain comprises Fab, Fab', F(ab')2, F(ab)2, variable fragment (Fv), domain antibody (dAb), or single chain variable fragment (scFv). In some embodiments, exemplary embodiments of multifunctional or multispecific molecules, e.g. , multifunctional or multispecific molecules comprising a tumor-associated antigen binding moiety, a TCRpV-binding moiety, and at least one cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL- 21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein, comprises a dimerization module comprising an Fc region comprising N297A mutation. FIGs. 15C-15H show exemplary embodiments of multifunctional or multispecific molecules, e.g., multifunctional or multispecific molecules comprising a tumor-associated antigen binding moiety, a TCRpV-binding moiety, and at least one cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein, wherein the multifunctional or multispecific molecules comprise an exemplary dimerization module, e.g., an Fc region comprising Knob-in-hole mutations and disulfide bridges. FIGs. 15I-15N show exemplary embodiments of multifunctional or multispecific molecules, e.g., multifunctional or multispecific molecules comprising a tumor-associated antigen binding moiety , a TCRpV-binding moiety, and at least one cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein, wherein the multifunctional or multispecific molecules comprise an exemplary dimerization module, e.g., an Fc region comprising disulfide bridges, but not comprising Knob-in-hole mutations. FIGs. 15O-15T show exemplary embodiments of multifunctional or multispecific molecules, e.g., multifunctional or multispecific molecules comprising a tumor-associated antigen binding moiety, a TCRpV-binding moiety, and at least one cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein,, wherein the multifunctional or multispecific molecules comprise an exemplary dimerization module, e.g., an Fc region not comprising disulfide bridges nor Knob-in-hole mutations. FIGs. 15C-15E, 15I-15K, and 15O-15Q show exemplary embodiments of multifunctional or multispecific molecules, e.g., multifunctional or multispecific molecules comprising a tumor-associated antigen binding moiety, a TCRpV-binding moiety, and at least one cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein, wherein the TCRpV-binding moiety comprises an scFv. FIGs. 15F-15H, 15L-15N, and 15R-15T show exemplary embodiments of multifunctional or multispecific molecules, e.g., multifunctional or multispecific molecules comprising a tumor-associated antigen binding moiety , a TCRpV-binding moiety, and at least one cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein, wherein the TCRpV-binding moiety comprises an Fab. FIG. 15U shows an exemplary embodiment of multifunctional or multispecific molecules, e.g., multifunctional or multispecific molecules comprising a tumor-associated antigen binding moiety, a TCRpV-bindingWSGR Docket No. 53676-759.601 moiety, and at least one cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein, wherein the multifunctional or multispecific molecule comprise two tumor- associated antigen binding moieties. The “a-TAA” as shown represents the tumor-associated antigen binding moiety. In some embodiments, the molecule that binds to a co-stimulatory receptor of a T cell comprises at least one cytokine molecule or a functional fragment or functional variant thereof, i.e., IL- 21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein. In some embodiments, the molecule that binds to a co-stimulatory receptor of a T cell comprises an antibody molecule, an antigen binding domain, a ligand, an extracellular domain of a receptor, or any combination thereof. In some embodiments, the molecule that binds to a co-stimulatory receptor of a T cell binds to CD2, 4-1BB, CD27, CD28, or any combination thereof.

[0293] FIGs 16A-16E show functional characterization of exemplary multifunctional or multispecific molecules as described herein, i.e., binding of various exemplary multifunctional or multispecific molecules as described herein comprising a TCRpV -binding moiety and a IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein to human cell types. FIG. 16A shows binding to HuT 78 cells dependent on the concentrations of exemplary multifunctional or multispecific molecules as described herein. FIG. 16B shows relative fluorescence intensity (RFI) for binding of exemplary multifunctional or multispecific molecules as described herein to human PBMC (CD8+T cell) dependent on concentration. FIG. 16C shows % CD25+using human PBMC and exemplary multifunctional or multispecific molecules as described herein dependent on concentration. FIG. 16D shows IFN-gamma concentration relative to the concentrations of exemplary multifunctional or multispecific molecules as described herein in human PBMC. FIG. 16E shows fold change of p- STAT3 (Y705) relative to the concentrations of exemplary multifunctional or multispecific molecules as described herein in HuT 78 cells. FIG. 16F shows the exemplary multifunctional or multispecific molecules used in FIGs. 16A-16E and their characteristics as demonstrated in FIGs. 16A-16E.

[0294] FIGs. 17A-17C shows serum stability of an exemplary multifunctional or multispecific molecule comprising a TCRpV-binding moiety and a IL-21, and a murine surrogate thereof comprising murine IL21. FIG. 17A shows a cartoon illustrating binding of an exemplary multifunctional or multispecific molecule comprising a TCRpV -binding moiety and IL-21 to an ELISA plate and an IL21Ralphagamma, which is connected to a fluorescent group (HRP) through biotin streptavidin interaction. FIG. 17B and FIG. 17C show the instability in serum of an exemplary multifunctional or multispecific molecule comprising a TCRpV -binding moiety and a IL-21 (FIG. 17C), and a murine surrogate thereof comprising murine IL21 (FIG. 17B) in both human and murine serum using pull-down assays.

[0295] FIGs. 18A and 18B show that six cleavage sites (91, 118, 119, 123, 124, 125) in wild-type IL-21 and affinity-optimized IL-21 muteins are predicted based on mass spectrometry data.

[0296] FIG. 19A shows an exemplary embodiment of multifunctional or multispecific molecules as described herein, e.g., multifunctional or multispecific molecules comprising two TCRpV -bindingWSGR Docket No. 53676-759.601 moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein, wherein the multifunctional or multispecific molecules comprise an exemplary dimerization module, e.g., an Fc region comprising disulfide bridges. FIG. 19B shows an exemplary embodiment of multifunctional or multispecific molecules as described herein, e.g., multifunctional or multispecific molecules comprising a TCRpV -binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein, wherein the multifunctional or multispecific molecules comprise an exemplary dimerization module, e.g., an Fc region comprising disulfide bridges. FIG. 19C shows an exemplary embodiment of multifunctional or multispecific molecules as described herein, e.g. , multifunctional or multispecific molecules comprising a TCRpV- binding moiety, and a human cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein, and a cytokine binding moiety (e.g., anti-IL-21 binding moiety), wherein the cytokine binding moiety is, for example, an scFv, wherein the multifunctional or multispecific molecules comprise an exemplary dimerization module, e.g., an Fc region comprising disulfide bridges. FIG. 19D shows an exemplary embodiment of human IL-21, human IL-4, and a IL-21 fusion polypeptide, i.e., a chimera molecule of human IL-21 and human IL-4, such as wherein R88to C" of human IL-4 replaces R76to C93of human IL-21. In some embodiments, the IL-21 fusion polypeptide is a chimera molecule of human IL-21 and human IL-2 (Chim-hIL-21 / 2), a chimera molecule of human IL-21 and human IL-4 (Chim-hIL-21 / 4), or a chimera molecule of human IL-21 and human IL-15 (Chim-hIL-21 / 15).

[0297] FIG. 20 shows the TCRpV and IL-21 binding of various exemplary multifunctional or multispecific molecules as described herein.

[0298] FIG. 21 shows exemplary IL-21 mutein engineering procedures. In some embodiments, three rounds of mutein engineering yielded murine and human panels with affinities in the range of 0.4 - 350 nM. By comparison, KD of a comparative IL-21 mutein is 350 nM.

[0299] FIG. 22A and FIG. 22B show p-STAT3 signaling of various exemplary embodiments of multifunctional or multispecific molecules as described herein, e.g., multifunctional or multispecific molecules comprising a TCR[3V-binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein (as represented as “IL21” in the cartoon of the configuration), wherein the multifunctional or multispecific molecules comprise an exemplary dimerization module, e.g., an Fc region comprising disulfide bridges, in huT78 T-cells, indicating exemplary embodiment of multifunctional or multispecific molecules as described herein exhibited a wide spectrum of biological activity. The responses as shown in FIG. 22A and FIG. 22B result only from interactions of the IL-21 arm with the IL-21R, as this cell line does not express TRBV6 or TRBV10. Further, responses as shown in FIG. 22A and FIG. 22B agree with SPR binding data derived with IL21Ra / CD 132.WSGR Docket No. 53676-759.601

[0300] FIG. 23 shows assessment of various exemplary embodiments of multifunctional or multispecific molecules as described herein, e.g., multifunctional or multispecific molecules comprising a TCR[3V -binding moiety and various IL-21 muteins (as represented as “hIL21” in the cartoon of the configuration), and % clipping of such IL-21 muteins, identifying IL-21 muteins with reduced affinity and improved production stability.

[0301] FIG. 24 shows the pSTAT3 EC50 and dissociation coefficient constant KD of human IL-21R alpha-gamma of various exemplary IL-21 muteins.

[0302] FIGs. 25A-25C demonstrates assessment of clipping liability of comparative multispecific molecules comprising wild-type IL-21. That is, FIGs. 25A-25C shows that a comparative multispecific molecules comprising wild-type IL-21 are prone to clipping in the IL21 arm during production of the multifunctional or multispecific molecules. As shown in FIGs. 25A-25C, substantial amounts of products produced do not correlate to the intact multispecific molecule (POI).

[0303] FIGs. 26A-26C show enhanced clipping observed in some exemplary multifunctional or multispecific molecules comprising certain exemplary IL-21 muteins during production of the multispecific molecules, although magnitude of clipping appeared to vary depending on the IL-21 muteins.

[0304] FIG. 27A demonstrates that an exemplary multifunctional or multispecific molecule as described herein comprising an exemplary IL-21 mutein, e.g., IL-21 mutein R9E R76A, shows clipping in production, but not in serum, similar to a comparative molecule comprising an anti-PD 1 binding domain instead of a TCRJ3V -binding moiety, while exemplary multifunctional or multispecific molecules comprising wild-type IL-21 showed clipping in both production and serum irrespective of the configuration. FIG. 27B shows the sequence of the comparative molecule comprising an anti-PD 1 binding domain and an exemplary IL-21 mutein R9E R76A.

[0305] FIG. 28 shows % clipping of exemplary multifunctional or multispecific molecules as described herein comprising exemplary IL-21 fusion polypeptides (as represented as “hIL21” in the cartoon of the configuration), i.e., IL-21 graft (chimera) muteins, during production of the multifunctional or multispecific molecules. For example, Graft#l IL-21 fusion polypeptide in which 16 residues in IL21 were replaced with 10 residues from hIL4 exhibited no clipped species identified, indicating substantial improvements in multifunctional or multispecific molecules production efficiency.

[0306] FIG. 29A shows an exemplary multifunctional or multispecific molecule as described herein comprising exemplary IL-21 fusion polypeptides (as represented as “IL21 / 4” in the cartoon of the configuration), i.e., IL-21 graft (chimera), that demonstrated reduced clipping during production (graft 1) as shown in FIG. 28. FIG. 29B and 29C show LC-MS (Non-reduced) and CE-SDS (Non-reduced) of the exemplary multifunctional or multispecific molecule comprising exemplary IL-21 fusion polypeptides (graft 1), respectively.

[0307] FIGs. 30A-F show exemplary embodiments of multifunctional or multispecific molecules as described herein, e.g., multifunctional or multispecific molecules comprising a TCRJ3V -binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e.,WSGR Docket No. 53676-759.601IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein (as represented as “IL21” in the cartoon of the configuration), wherein the multifunctional or multispecific molecules comprise an exemplary dimerization module, e.g., an Fc region comprising disulfide bridges, wherein the TCRpV-binding moiety can be, for example, an scFv. FIG. 30A shows structures of exemplary molecules BNM0333, BNM0432, and BNM0477. FIG. 30B shows structures of exemplary molecules BNM0478, BNM0479, and BNM0480. FIG. 30C shows structures of exemplary molecules BLM0321, BNM0008, BNM0025, BMM0795, BNM0005, BNM0021, BNM0156, BNM0152, BNM0155, BMM0006, BNM0209, BNM0207, BNM0208, BMM0736, BNM0658, BNM0208, BNM0473, BNM0378, BNM0376, BNM0476, BNM0375, BNM0663, BNM0741, BNM0742, BNM0743, BNM0744, BNM0747, BMM0032, BMM0697, BMM0696, BNM0780, BNM0794, BNM0796, BOM0083, BNM0714-BNM0737, BNM0740, BNM0778-BNM0803, and BOM0077-BGM0083. FIG. 30D shows structures of exemplary molecules BNM0408, BNM0411, BNM0412, and BNM0659. FIG. 30E shows structures of exemplary molecules BNM0409, BNM0410, and BNM0660. FIG. 30F shows structures of exemplary molecules BNM0480, BNM0661, and BNM0662. FIG. 30G shows structures of exemplary molecules BNM0432, BNM0749, and BNM0739. FIG. 30H shows structures of exemplary molecules BNM0333, BNM0748, and BNM0738.

[0308] FIG. 31A shows an exemplary embodiment of multifunctional or multispecific molecule as described herein, BNM0480, e.g., a multifunctional or multispecific molecule comprising a TCRJ3V- binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein (as represented as “IL21” in the cartoon of the configuration), wherein the multifunctional or multispecific molecules comprise an exemplary dimerization module, e.g., an Fc region comprising disulfide bridges. FIGs. 31B and 31C shows LC-MS (Non-reduced) and CE-SDS (Non-reduced) of BNM0480, respectively, showing the production of the protein of interest (POI), including the dimer illustrated in FIG. 31B.

[0309] FIG. 32A shows an exemplary embodiment of multifunctional or multispecific molecules as described herein produced by introducing a non-neutralizing (e.g., shielding) domain, i.e., multifunctional or multispecific molecules comprising an IL-21 binding moiety fused with a multifunctional or multispecific molecules comprising a TCRpV-binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein (as represented as “hIL21” in the cartoon of the configuration). In some embodiments, fusing a nonneutralizing anti-IL21 binding domain to IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof shields IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof from proteases. In some embodiments, fusing a non -neutralizing anti-IL21 binding domain to IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof also reduces positive charge of IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof. FIG. 32B shows alternative configurations of an exemplary multifunctionalWSGR Docket No. 53676-759.601 or multispecific molecules as described herein comprising an IL-21 binding moiety fused with a multifunctional or multispecific molecules comprising a TCRpV-binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein.

[0310] FIG. 33 shows % clipping of an exemplary embodiment of multifunctional or multispecific molecules as described herein, e.g., multifunctional or multispecific molecules comprising a TCRpV- binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein, fused with an IL-21 binding moiety.

[0311] FIG. 34 shows clipping associated with different configurations of exemplary multifunctional or multispecific molecules as described herein comprising an IL-21 binding moiety fused with a multifunctional or multispecific molecules comprising a TCRpV-binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein. In this example, fusion to the C-terminal of the light chain demonstrated reduced clipping.

[0312] FIG. 35A and FIG. 35B demonstrates the affinity matrix of murine surrogates of exemplary multifunctional or multispecific molecules as described herein, showing in vitro characterization of murine surrogates of exemplary multifunctional or multispecific molecules as described herein. FIG. 35A shows the breakdown of BALB / c splenocytes cell types and the viability of such cells when exposed to various murine surrogates of exemplary multifunctional or multispecific molecules comprising a TCRpV-binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein, in a concentration dependent manner. FIG. 35B shows binding affinity of various multifunctional or multispecific molecules comprising a TCRpV-binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein. Certain construct demonstrates good binding to both vB and IL-21R alpha-gamma, whereas others show better binding for one over the other. The multifunctional or multispecific molecules with the note “RSVT” comprise anti-RSV binding domain, instead of a TCRpV-binding moiety.

[0313] FIGs. 36A-36E demonstrate the CD8+ and CD4+ T-cell activation summary by the murine surrogates of exemplary multifunctional or multispecific molecules as described herein. FIGs. 36A and 36B show % CD25+of CD3+CD8+ cells and CD3+CD4+ cells, respectively, by murine surrogates of various exemplary multifunctional or multispecific molecules comprising a TCRpV-binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein, in various concentrations in BALB / c splenocytes. FIGs. 36C and 36D show CD25 RFI of CD3+CD8+ cells and CD3+CD4+ cells, respectively, by murine surrogates of various exemplary multifunctional or multispecific molecules comprising a TCRpV-binding moiety, and a cytokine molecule or a functionalWSGR Docket No. 53676-759.601 fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein., in various concentrations in BALB / c splenocytes. FIG. 36E shows binding affinity and EC50 values as shown in FIGs. 36A-36E of murine surrogates of various exemplary multifunctional or multispecific molecules as described herein comprising a TCRpV-binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein. Certain construct demonstrates good binding to both TCRpV and IL-21R alpha-gamma, whereas others show better binding for one over the other. The multifunctional or multispecific molecules with the note “RSVT” comprise anti-RSV binding domain, instead of a TCRpV-binding moiety.

[0314] FIGs. 37A-37C demonstrate Interferon gamma (IFN-y) quantification of murine surrogates of various exemplary multifunctional or multispecific molecules as described herein comprising a TCRJ3V- binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein, in various concentrations. FIG. 37A shows Interferon gamma (IFN-y) quantification of murine surrogates of various exemplary multifunctional or multispecific molecules as described herein having high TCRpV binding affinity, FIG. 37B shows Interferon gamma (IFN-y) quantification of murine surrogates of various exemplary multifunctional or multispecific molecules as described herein having middle TCRpV binding affinity, and FIG. 37C shows Interferon gamma (IFN-y) quantification of murine surrogates of various exemplary multifunctional or multispecific molecules as described herein having low TCRpV binding affinity. FIG. 37D shows binding affinity and EC50 values as shown in FIGs. 37A-36C of murine surrogates of various exemplary multifunctional or multispecific molecules comprising a TCRpV-binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein. The multifunctional or multispecific molecules with the note “RSVT” comprise anti-RSV binding domain, instead of a TCRpV-binding moiety.

[0315] FIGs. 38A-38C demonstrate regulatory T cell in CD3+CD4+ cells by murine surrogates of various exemplary multifunctional or multispecific molecules as described herein comprising a TCRJ3V- binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein, in various concentrations. FIG. 38A shows % FoxP3+CD25hlghin CD3+CD4+ cells by murine surrogates of various exemplary multifunctional or multispecific molecules as described herein having high TCRJ3V binding affinity, FIG. 38B shows % FoxP3+CD25hlghin CD3+CD4+ cells by murine surrogates of various exemplary multifunctional or multispecific molecules as described herein having middle TCRJ3V binding affinity, and FIG. 38C shows % FoxP3+CD25hlghin CD3+CD4+ cells by murine surrogates of various exemplary multifunctional or multispecific molecules as described herein having low TCRJ3V binding affinity.WSGR Docket No. 53676-759.601

[0316] FIGs. 39A-39C demonstrate IL-21 dependent B-cell apoptosis by murine surrogates of various exemplary multifunctional or multispecific molecules as described herein comprising a TCRpV-binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein, in various concentrations. FIGs. 39A and 39B show cell number per well in CD3 NKG2A CD19+cells by murine surrogates of various exemplary multifunctional or multispecific molecules comprising a TCRpV-binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein, and multifunctional or multispecific molecules comprising an anti-RSV binding domain, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein in various concentrations in BALB / c splenocytes. FIG. 39C shows binding affinity and EC50 values as shown in FIGs. 39A and 39B of murine surrogates of various exemplary multifunctional or multispecific molecules comprising a TCRpV-binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein. Certain construct demonstrates good binding to both TCRpV and IL-21R alpha-gamma, whereas others show better binding for one over the other. The multifunctional or multispecific molecules with the note “RSVT” comprise anti-RSV binding domain, instead of a TCRpV-binding moiety.

[0317] FIG. 40 shows a scheme of an assessment of pharmacodynamics of murine surrogates of various exemplary multifunctional or multispecific molecules as described herein comprising a TCRpV-binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein, in a MC38 tumor mouse model. In some embodiments, MC38 tumor model with murine affinity matrix IL21 constructs are evaluated at 3.0 mg / kg, and 6.0 mg / kg,IP, QW. In some embodiments, constructs include TCRvbl3.2 x mIL21 (total 4 constructs) and RSV x mIL21. In some embodiments, mice are monitored biweekly for body weight and tumor volume measurements. After 4 days final dosing, whole blood and tumor are collected for flow analysis.

[0318] FIGs. 41A-41E demonstrate that murine surrogates of various exemplary multifunctional or multispecific molecules as described herein comprising a TCRpV-binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein display weak pharmacodynamics signatures in vivo. FIG. 41A shows binding affinity and dosage of murine surrogates of various exemplary multifunctional or multi specific molecules comprising a TCRpV- binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein. Certain construct demonstrates good binding to both TCRpV and IL-21R alpha-gamma, whereas others show better binding for one over the other. FIGs. 41B and 41 C show %WSGR Docket No. 53676-759.601TRBV13+and TRBV13+ / ml, respectively, in CD3+CD8+ cells in whole blood by murine surrogates of various exemplary multifunctional or multispecific molecules comprising a TCRpV-binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein, in various concentrations. FIGs. 41D and 41E show Granzyme B+ / ml in CD3+CD8+TRBV13 cells, and NK cells / ml in CD3-CD49b+ cells, respectively, in whole blood by murine surrogates of various exemplary multifunctional or multispecific molecules comprising a TCRpV-binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein, in various concentrations. The multifunctional or multispecific molecules with the note “RSVT” comprise anti-RSV binding domain, instead of a TCRpV-binding moiety.

[0319] FIGs. 42A-42C demonstrate TRBV13+ CD8 T-cell expansion by murine surrogates of various exemplary multifunctional or multispecific molecules as described herein comprising a TCRpV-binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein. FIG. 42A shows binding affinity and dosage of murine surrogates of various exemplary multifunctional or multispecific molecules comprising a TCRpV-binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein. Certain construct demonstrates good binding to both TCRpV and IL-21R alpha-gamma, whereas others show better binding for one over the other. FIGs. 42B and 41 C show % TRBV13+and TRBV13+ / ml, respectively, in in CD3+CD8+ cells in whole blood by murine surrogates of various exemplary multifunctional or multispecific molecules comprising a TCRpV-binding moiety, and a cytokine molecule or a functional fragment or functional variant thereof as described herein, i.e., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein, in various concentrations. The multifunctional or multispecific molecules with the note “RSVT” comprise anti-RSV binding domain, instead of a TCRpV-binding moiety.

[0320] FIG. 43A - FIG. 43D illustrate exemplary embodiments of multifunctional or multispecific molecules as described herein. FIG. 43A shows an exemplary illustration of exemplary molecule BOM0076 comprising an N297A point mutation, a TCRpV-binding domain, and a cytokine molecule (e.g., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof) as described herein. FIG. 43B shows an exemplary illustration of exemplary molecule BOM0187 comprising an N297A point mutation, an RSV-binding domain, and a cytokine molecule (e.g., IL-21, IL- 21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof) as described herein. FIG. 43C shows an exemplary molecule BNM0800 comprising an N297A point mutation, TCRpV- binding domain, and a cytokine molecule (e.g., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof) as described herein. FIG. 43D shows an exemplary illustration of exemplary molecule BOM0190 comprising an N297A point mutation, an RSV-binding domain, and aWSGR Docket No. 53676-759.601 cytokine molecule (e.g., IL-21, IL-21 mutein, IL-21 fusion polypeptide, or a functional fragment or variant thereof) as described herein.

[0321] FIG. 44A and FIG. 44B illustrate the results of an in vitro assay quantifying normalized T cell binding (% bound x mean fluorescence intensity (MFI) of bound) by exemplary molecules BOM0187, BOM0076, BOM0190, BNM0800, and BJM0786 in human PBMCs. FIG. 44A shows normalized binding of exemplary molecules BOM0187, BOM0076, BOM0190, BNM0800, and BJM0786 to CD8+ T cells. FIG. 44B shows normalized binding of exemplary molecules BOM0187, BOM0076, BOM0190, BNM0800, and BJM0786 to CD4+ T cells.

[0322] FIG. 45A and FIG. 45B illustrate the results of an in vitro assay quantifying T cell activation and expansion by exemplary molecules BOM0187, BOM0076, BOM0190, BNM0800, and BJM0786 in human PBMCs. FIG. 45A shows the percentage by which CD25+ is upregulated in CD8+ T cells in response to exemplary molecules BOM0187, BOM0076, BOM0190, BNM0800, or BJM0786 administration. FIG. 45B shows the number of CD8+ T cells which are expressing CD25+ in response to exemplary molecules BOM0187, BOM0076, BOM0190, BNM0800, or BJM0786 administration.

[0323] FIG. 46A - FIG. 46E illustrate the results of an in vitro assay quantifying T cell activation over a 7-day period following administration of exemplary molecules BOM0187, BOM0076, BOM0190, BNM0800, or BJM0786 (lOOnM) in human PBMCs. FIG. 46A shows the percentage of CD8+ T cells expressing TCRVP in response to exemplary molecule administration. FIG. 46B shows the percentage of CD25+ CD8+ T cells following exemplary molecule administration. FIG. 46C shows the percentage of CD25+ CD8+ TCRVJ3- T cells following exemplary molecule administration. FIG. 46D shows the percentage of CD25+ CD8+ TCRVP+ T cells following exemplary molecule administration. FIG. 46E shows ratio of CD8+ T cells to CD4+ T cells following exemplary molecule administration.

[0324] FIG. 47A and FIG. 47B illustrate the results of an in vitro assay quantifying T cell expansion over a 7-day period following administration of exemplary molecules (lOnM) in human PBMCs. FIG. 47A shows expansion of CD8+ TCRVP+ T cells following exemplary molecule administration. FIG. 47B shows expansion of CD8+ TCRVP- T cells following exemplary molecule administration.

[0325] FIG. 48 shows the ratio between the fold change in CD8+ T cells to the fold change in CD4+ T cells as a function of exemplary molecule dose in human PBMCs.

[0326] FIG. 49A and FIG. 49B show the fold change in CD8+ T cells and the fold change in CD4+ T cells as a function of exemplary molecule dose in human PBMCs. FIG. 49A shows the fold change in CD8+ and CD4+ T cells in response to exemplary molecule BOM0076 administration. FIG. 49B shows the fold change in CD8+ and CD4+ T cells in response to exemplary molecule BGM0800 administration.

[0327] FIG. 50A and FIG. 50B illustrate the impact of exemplary molecule administration on B cell populations in human PBMCs. FIG. 50A shows the number of B cells per well as a function of exemplary molecule administration. FIG. 50B shows the percentage of CD3- cells as a function of exemplary molecule administration.

[0328] FIG. 51A and FIG. 51B illustrate the impact of exemplary molecule administration on NK cell and NK-T cell populations in human PBMCs. FIG. 51A shows the percentage of CD3- cells as aWSGR Docket No. 53676-759.601 function of exemplary molecule administration. FIG. 51B shows the percentage of CD3+ cells as a function of exemplary molecule administration.

[0329] FIG. 52 illustrates the impact of exemplary molecule administration on regulatory T cell populations in human PBMCs by showing the percentage of FoxP3+ cells as a function of exemplary molecule administration.

[0330] FIG. 53A - FIG. 53C illustrate the impact of exemplary molecule administration (lOOnM) in various immune cell populations over a 7-day period in human PBMCs. FIG. 53 A shows the number of B cells following exemplary molecule administration. FIG. 53B shows the number of NK cells following exemplary molecule administration. FIG. 53C shows the number of CD8+ T cells following exemplary molecule administration.

[0331] FIG. 54A and FIG. 54B illustrate the magnitude of Granzyme B (GzB) activation in CD 8+ T cells as a function of exemplary molecule administration in human PBMCs. FIG. 54A shows the percentage of GzB+ CD8+ T cells as a function of exemplary molecule administration. FIG. 54B shows the relative fluorescence intensity (RFI) of GzB+ CD8+ T cells as a function of exemplary molecule administration.

[0332] FIG. 55A and FIG. 55B illustrate the magnitude of Granzyme B (GzB) activation in CD4+ T cells as a function of exemplary molecule administration in human PBMCs. FIG. 54A shows the percentage of GzB+ CD4+ T cells as a function of exemplary molecule administration. FIG. 54B shows the relative fluorescence intensity (RFI) of GzB+ CD4+ T cells as a function of exemplary molecule administration.

[0333] FIG. 56A - FIG. 56E illustrate the magnitude of cytokine production as a function of exemplary molecule administration in human PBMCs. FIG. 56A shows the concentration of IFNy as a function of exemplary molecule administration. FIG. 56B shows the concentration of IL- 1 [3 as a function of exemplary molecule administration. FIG. 56C shows the concentration of IL-6 as a function of exemplary molecule administration. FIG. 56D shows the concentration of TNF-a as a function of exemplary molecule administration. FIG. 56E shows the concentration of IL- 10 as a function of exemplary molecule administration.

[0334] FIG. 57A and FIG. 57B illustrate IL-21 receptor signaling, as measured by phosphorylated STAT3 (pSTAT3) levels, following administration of lOOnM of exemplary molecules in human PBMCs. FIG. 57A shows the fold change in pSTAT3 levels following exemplary molecule administration over a 100-minute period. FIG. 57B shows the fold change in pSTAT3 levels 15 minutes following exemplary molecule administration.

[0335] FIG. 58A and FIG. 58B illustrate TCR signaling, as measured by phosphorylated ERK (pERK) levels, following administration of lOOnM of exemplary molecules in human PBMCs. FIG. 58A shows the fold change in pERK levels following exemplary molecule administration over a 100-minute period. FIG. 58B shows the fold change in pERK levels 15 minutes following IL-21 fusion polypeptide administration.WSGR Docket No. 53676-759.601

[0336] FIG. 59A and FIG. 59B illustrate TCR signaling, as measured by phosphorylated SLP76 (pSLP76) levels, following administration of lOOnM of exemplary molecules in human PBMCs. FIG. 59A shows the fold change in pSLP76 levels following exemplary molecule administration over a 100- minute period. FIG. 59B shows the fold change in pSLP76 levels 15 minutes following exemplary molecule administration.

[0337] FIG. 60A and FIG. 60B illustrate the extent of T cell central memory, defined as VP+ CD95+ CD27+ CCR7+ CD45RA-, formed 5 days following administration of lOOnM of exemplary molecules in human PBMCs. FIG. 60A shows percentage of CD8+ T cells which formed central memory 5 days following administration of lOOnM of exemplary molecules. FIG. 60B shows percentage of CD4+ T cells which formed central memory 5 days following administration of lOOnM of exemplary molecules.

[0338] FIG. 61A - FIG. 61H illustrate stimulation and expansion of specific T cell subtypes in response to stimulation by lOnM of exemplary molecules for a 5 -day period, followed by TRBV gene expression analysis in human PBMCs. FIG. 61A shows the percentage of TRJ3V+ T cells expressing TRpV 6-1 before and after exemplary molecule administration. FIG. 61B shows the percentage of TRJ3V+ T cells expressing TRpV 6-2 before and after exemplary molecule administration. FIG. 61C shows the percentage of TRJ3V+ T cells expressing TRpV 6-4 before and after exemplary molecule administration. FIG. 61D shows the percentage of TRJ3V+ T cells expressing TRpV 6-5 before and after exemplary molecule administration. FIG. 61E shows the percentage of TRJ3V+ T cells expressing TRpV 10-1 before and after exemplary molecule administration. FIG. 61F shows the percentage of TRJ3V+ T cells expressing TRpV 10-2 before and after exemplary molecule administration. FIG. 61G shows the percentage of TRJ3V+ T cells expressing TRpV 10-3 before and after exemplary molecule administration. FIG. 61H shows the fold change in expansion of TRJ3V6 / 1O+ T cells before versus after exemplary molecule administration.

[0339] FIG. 62A - FIG. 62D illustrate exemplary models of mouse exemplary molecules. FIG. 62A shows an exemplary illustration of exemplary molecule BGM0003 (mouse surrogate for BOM0076) comprising a LALA-PG mutation, TCRpV-binding domain, and an IL21 domain. FIG. 62B shows an exemplary illustration of control molecule BOM0101 (mouse surrogate for BOM0187) comprising a LALA-PG point mutation, an RSV-binding domain, and an IL21 domain. FIG. 62C shows an exemplary illustration of exemplary molecule BNM1007 (mouse surrogate for BNM0800) comprising a LALA-PG mutation, TCRpV-binding domain, and an IL21 domain. FIG. 62D shows an exemplary illustration of control molecule BOM0052 (mouse surrogate for BOM0190) comprising a LALA-PG mutation, an RSV-binding domain, and an IL21 domain.

[0340] FIG. 63A - FIG. 63D illustrate the impact of intraperitoneal (IP) administration of exemplary molecules in ascending doses (0. 1, 0.3, 1, 3 mg / kg) on tumor volume and survival in a 4T1 mouse model. FIG. 63A shows tumor volume (mm3) following administration of exemplary molecule BGM0003 (mouse surrogate for BOM0076) or control molecule BOM0101 (mouse surrogate for BOM0187) over a 30-35-day period. FIG. 63B shows tumor volume (mm3) following administration of exemplary molecule BNM1007 (mouse surrogate for BNM0800) or control molecule BOM0052 (mouse surrogateWSGR Docket No. 53676-759.601 for BOM0190) over a 30-35-day period. FIG. 63C shows probability of survival following administration of exemplary molecule BGM0003 (mouse surrogate for BOM0076) or control molecule BOM0101 (mouse surrogate for BOM0187) over a 40-80-day period. FIG. 63D shows probability of survival following administration of exemplary molecule BNM1007 (mouse surrogate for BNM0800) or control molecule BOM0052 (mouse surrogate for BOM0190) over a 40-80-day period.

[0341] FIG. 64A and FIG. 64B illustrate protection against tumor rechallenge following intraperitoneal (IP) administration of exemplary molecules at 3 mg / kg in a 4T1 mouse model. FIG. 64A shows tumor volume (mm3) following administration of exemplary molecule BGM0003 (mouse surrogate for BOM0076) or control molecule BOM0101 (mouse surrogate for BOM0187) over a 130-140-day period. FIG. 64B shows tumor volume (mm3) following administration of exemplary molecule BNM1007 (mouse surrogate for BNM0800) or control molecule BOM0052 (mouse surrogate for BOM0190) over a 130-140-day period.

[0342] FIG. 65A and FIG. 65B illustrate the impact of intraperitoneal (IP) administration of exemplary molecules in ascending doses (0. 1, 0.3, 1, 3 mg / kg) on body weight in a 4T1 mouse model. FIG. 65A shows the percentage change in body weight following administration of exemplary molecule BGM0003 (mouse surrogate for BOM0076) or control molecule BOM0101 (mouse surrogate for BOM0187) over a 25-30-day period. FIG. 65B shows the percentage change in body weight following administration of exemplary molecule BNM1007 (mouse surrogate for BNM0800) or control molecule BOM0052 (mouse surrogate for BOM0190) over a 25-30-day period.

[0343] FIG. 66 illustrates an exemplary experimental flowchart outlining the timeline for assessing the impact of exemplary molecule administration on various pharmacodynamic parameters in a 4T1 mouse model.

[0344] FIG. 67A - FIG. 67D illustrate the magnitude of selective T cell expansion in blood and tumor samples from 4T1 mice following intraperitoneal (IP) administration of exemplary molecules at 3 mg / kg over a 10-15-day period. FIG. 67A shows the percentage of TCRVP13+ CD8+ T cells and TCRVP13+ CD4+ T cells in a whole blood sample following administration of exemplary molecule BGM0003 (mouse surrogate for BOM0076). FIG. 67B shows the percentage of TCRVP13+ CD8+ T cells and TCRVP13+ CD4+ T cells in a tumor sample following administration of exemplary molecule BGM0003 (mouse surrogate for BOM0076). FIG. 67C shows the percentage of TCRVP13+ CD8+ T cells and TCRVP13+ CD4+ T cells in a whole blood sample following administration of exemplary molecule BNM1007 (mouse surrogate for BNM0800). FIG. 67D shows the percentage of TCRVP13+ CD8+ T cells and TCRVP13+ CD4+ T cells in a tumor sample following administration of exemplary molecule BNM1007 (mouse surrogate for BNM0800).

[0345] FIG. 68A - FIG. 68D illustrate the magnitude of TCRVP13+ CD8+ T cell expansion in blood and tumor samples from 4T1 mice following intraperitoneal (IP) administration of ascending doses of exemplary molecules (0.1, 0.3, 1, or 3 mg / kg) over a 10-15-day period. FIG. 68A shows the percentage of TCRVP13+ CD8+ T cells in a whole blood sample following administration of exemplary molecule BGM0003 (mouse surrogate for BOM0076). FIG. 68B shows the percentage of TCRVP13+ CD8+ TWSGR Docket No. 53676-759.601 cells in a tumor sample following administration of exemplary molecule BOM0003 (mouse surrogate for BOM0076). FIG. 68C shows the percentage of TCRVP13+ CD8+ T cells in a whole blood sample following administration of exemplary molecule BNM1007 (mouse surrogate for BNM0800). FIG. 68D shows the percentage of TCRVP13+ CD8+ T cells in atumor sample following administration of exemplary molecule BNM1007 (mouse surrogate for BNM0800).

[0346] FIG. 69A - FIG. 69H illustrate expansion of TCRVP13+ CD8+ T cells expressing specific markers (Ki67, GzB, CD25, and PD1) in blood and tumor samples from 4T1 mice following intraperitoneal (IP) administration of ascending doses of exemplary molecule BGM0003 (mouse surrogate for BOM0076) (0.1, 0.3, 1, or 3 mg / kg) over a 10-15-day period. FIG. 69A shows the number of Ki67+ TCRVP13+ CD8+ T cells per mb in blood samples as a function of BGM0003 (mouse surrogate for BOM0076) administration. FIG. 69B shows the number of Ki67+ TCRVP13+ CD8+ T cells per gram (g) in tumor samples as a function of BGM0003 (mouse surrogate for BOM0076) administration. FIG. 69C shows the number of GzB+ TCRVP13+ CD8+ T cells per mb in blood samples as a function of BGM0003 (mouse surrogate for BOM0076) administration. FIG. 69D shows the number of GzB+ TCRVP13+ CD8+ T cells per gram (g) in tumor samples as a function of BGM0003 (mouse surrogate for BOM0076) administration. FIG. 69E shows the number of CD25+ TCRVP13+ CD8+ T cells per mb in blood samples as a function of BGM0003 (mouse surrogate for BOM0076) administration. FIG. 69F shows the number of CD25+ TCRVP13+ CD8+ T cells per gram (g) in tumor samples as a function of BGM0003 (mouse surrogate for BOM0076) administration. FIG. 69G shows the number of PD1+ TCRVP13+ CD8+ T cells per mb in blood samples as a function of BGM0003 (mouse surrogate for BOM0076) administration. FIG. 69H shows the number of PD1+ TCRVP13+ CD8+ T cells per gram (g) in tumor samples as a function of BGM0003 (mouse surrogate for BOM0076) administration.

[0347] FIG. 70A - FIG. 70D illustrate the magnitude of NK cell expansion in blood and tumor samples from 4T1 mice following intraperitoneal (IP) administration of ascending doses of exemplary molecule BGM0003 (mouse surrogate for BOM0076) (0.1, 0.3, 1, or 3 mg / kg) over a 10-15-day period. FIG. 70A shows the percentage of CD45+ cells, wherein CD45+ can be a marker of NK cells, in whole blood samples as a function of BGM0003 (mouse surrogate for BOM0076) administration. FIG. 70B shows the number ofNK cells per mb in whole blood samples as a function of BGM0003 (mouse surrogate for BOM0076) administration. FIG. 70C shows the percentage of CD45+ cells, wherein CD45+ can be a marker of NK cells, in tumor samples as a function of BGM0003 (mouse surrogate for BOM0076) administration. FIG. 70D shows the number of NK cells per gram (g) in tumor samples as a function of BGM0003 (mouse surrogate for BOM0076) administration.

[0348] FIG. 71A - FIG. 71C illustrate the relationship between intraperitoneal (IP) administration of ascending doses of exemplary molecule BGM0003 (mouse surrogate for BOM0076) (0.1, 0.3, 1, or 3 mg / kg) and the prevalence of specific T cell populations in a tumor sample of 4T1 mice over a 10-15-day period. FIG. 71A shows the percentage of CD4+ FoxP3+ CD3+ T cells as a function of BGM0003 (mouse surrogate for BOM0076) administration in a tumor sample. FIG. 71B shows the number ofWSGR Docket No. 53676-759.601FoxP3+ T cells per gram (g) in tumor samples as a function of BOM0003 (mouse surrogate for BOM0076) administration in a tumor sample. FIG. 71C shows the ration of CD8+ T cells to regulatory T cells as a function of BGM0003 (mouse surrogate for BOM0076) administration in a tumor sample.

[0349] FIG. 72A - FIG. 72F illustrate the effects of depletion of CD4+ or CD8+ T cells on the antitumor activity and survival following intraperitoneal (IP) administration of exemplary molecules at 3 mg / kg in a CT26 mouse model. FIG. 72A shows tumor volume (mm3) following BGM0003 (mouse surrogate for BOM0076) administration alone, BGM0003 (mouse surrogate for BOM0076) administration with CD8+ T cell depletion, or BGM0003 (mouse surrogate for BOM0076) administration with CD4+ T cell depletion over a 22-day period. FIG. 72B shows tumor volume (mm3) following BNM1007 (mouse surrogate for BNM0800) administration alone, BNM1007 administration with CD8+ T cell depletion, or BNM1007 (mouse surrogate for BNM0800) administration with CD4+ T cell depletion over a 22-day period. FIG. 72C shows percent tumor growth inhibition (TGI) following BGM0003 (mouse surrogate for BOM0076) administration alone, BGM0003 (mouse surrogate for BOM0076) administration with CD8+ T cell depletion, or BGM0003 (mouse surrogate for BOM0076) administration with CD4+ T cell depletion over a 22-day period. FIG. 72D shows percent tumor growth inhibition (TGI) following BNM1007 (mouse surrogate for BNM0800) administration alone, BNM1007 (mouse surrogate for BNM0800) administration with CD8+ T cell depletion, or BNM1007 (mouse surrogate for BNM0800) administration with CD4+ T cell depletion over a 22-day period. FIG. 72E shows probability of survival following BGM0003 (mouse surrogate for BOM0076) administration alone, BGM0003 (mouse surrogate for BOM0076) administration with CD8+ T cell depletion, or BGM0003 (mouse surrogate for BOM0076) administration with CD4+ T cell depletion overtime postgrafting. FIG. 72F shows probability of survival following BNM1007 (mouse surrogate for BNM0800) administration alone, BNM1007 (mouse surrogate for BNM0800) administration with CD8+ T cell depletion, or BNM1007 (mouse surrogate for BNM0800) administration with CD4+ T cell depletion over time post-grafting.

[0350] FIG. 73A - FIG. 73F illustrate the effects of depletion of TCRVP+ T cells on the anti-tumor activity and survival following intraperitoneal (IP) administration of exemplary molecules at 3 mg / kg in a CT26 mouse model. FIG. 73A shows tumor volume (mm3) following BGM0003 (mouse surrogate for BOM0076) administration alone, or BGM0003 (mouse surrogate for BOM0076) administration with TCRVP+ T cell depletion (BJM1117) over a 22-day period. FIG. 73B shows tumor volume (mm3) following BNM1007 (mouse surrogate for BNM0800) administration alone, or BNM1007 (mouse surrogate for BNM0800) administration with TCRVP+ T cell depletion (BJM1117) over a 22-day period. FIG. 73C shows percent tumor growth inhibition (TGI) following BGM0003 (mouse surrogate for BOM0076) administration alone, or BGM0003 (mouse surrogate for BOM0076) administration with TCRVP+ T cell depletion (BJM1117) over a 22-day period. FIG. 73D shows percent tumor growth inhibition (TGI) following BNM1007 (mouse surrogate for BNM0800) administration alone, or BNM1007 (mouse surrogate for BNM0800) administration with TCRVP+ T cell depletion (BJM1117) over a 22-day period. FIG. 73E shows probability of survival following BGM0003 (mouse surrogate forWSGR Docket No. 53676-759.601BOM0076) administration alone, or BOM0003 (mouse surrogate for BOM0076) administration with TCRVP+ T cell depletion (BJM1117) overtime post-grafting. FIG. 73F shows probability of survival following BNM1007 (mouse surrogate for BNM0800) administration alone, or BNM1007 (mouse surrogate for BNM0800) administration with TCRVP+ T cell depletion (BJM1117) over time postgrafting.

[0351] FIG. 74A - FIG. 74F illustrate the effects of depletion of CD4+ or CD8+ T cells on the antitumor activity and survival following intraperitoneal (IP) administration of exemplary molecules at 3 mg / kg in a 4T1 mouse model. FIG. 74A shows tumor volume (mm3) following BGM0003 (mouse surrogate for BOM0076) administration alone, BGM0003 (mouse surrogate for BOM0076) administration with CD8+ T cell depletion, or BGM0003 (mouse surrogate for BOM0076) administration with CD4+ T cell depletion over a 22-day period. FIG. 74B shows tumor volume (mm3) following BNM1007 (mouse surrogate for BNM0800) administration alone, BNM1007 (mouse surrogate for BNM0800) administration with CD8+ T cell depletion, or BNM1007 (mouse surrogate for BNM0800) administration with CD4+ T cell depletion over a 22-day period. FIG. 74C shows percent tumor growth inhibition (TGI) following BGM0003 (mouse surrogate for BOM0076) administration alone, BGM0003 (mouse surrogate for BOM0076) administration with CD8+ T cell depletion, or BGM0003 (mouse surrogate for BOM0076) administration with CD4+ T cell depletion over a 22-day period. FIG. 74D shows percent tumor growth inhibition (TGI) following BNM1007 (mouse surrogate for BNM0800) administration alone, BNM1007 (mouse surrogate for BNM0800) administration with CD8+ T cell depletion, or BNM1007 (mouse surrogate for BNM0800) administration with CD4+ T cell depletion over a 22-day period. FIG. 74E shows probability of survival following BGM0003 (mouse surrogate for BOM0076) administration alone, BGM0003 (mouse surrogate for BOM0076) administration with CD8+ T cell depletion, or BGM0003 (mouse surrogate for BOM0076) administration with CD4+ T cell depletion over time post-grafting. FIG. 74F shows probability of survival following BNM1007 (mouse surrogate for BNM0800) administration alone, BNM1007 (mouse surrogate for BNM0800) administration with CD8+ T cell depletion, or BNM1007 (mouse surrogate for BNM0800) administration with CD4+ T cell depletion overtime post-grafting.

[0352] FIG. 75A - FIG. 75C illustrate the effects of depletion of TCRVP+ T cells on the anti-tumor activity and survival following intraperitoneal (IP) administration of exemplary molecules at 3 mg / kg in a 4T1 mouse model. FIG. 75A shows tumor volume (mm3) following BGM0003 (mouse surrogate for BOM0076) administration alone, or BGM0003 (mouse surrogate for BOM0076) administration with TCRVP+ T cell depletion (BJM1117) over a 22-day period. FIG. 75B shows percent tumor growth inhibition (TGI) following BGM0003 (mouse surrogate for BOM0076) administration alone, or BGM0003 (mouse surrogate for BOM0076) administration with TCRVP+ T cell depletion (BJM1117) over a 22-day period. FIG. 75C shows probability of survival following BGM0003 (mouse surrogate for BOM0076) administration alone, or BGM0003 (mouse surrogate for BOM0076) administration with TCRVP+ T cell depletion (BJM1117) overtime post-grafting.WSGR Docket No. 53676-759.601

[0353] FIG. 76A - FIG. 76D illustrate anti -tumor activity by depletion of TCRVJ3+ T cells combined with intraperitoneal (IP) exemplary molecule administration at 3 mg / kg in a 4T1 mouse model over a 26- day period. FIG. 76A shows tumor volume (mm3) following BGM0003 (mouse surrogate for BOM0076) administration alone, or BGM0003 (mouse surrogate for BOM0076) administration with TCRVJ3+ T cell depletion over a 26-day period. FIG. 76B shows percent tumor growth inhibition (TGI) following BGM0003 (mouse surrogate for BOM0076) administration alone, or BGM0003 (mouse surrogate for BOM0076) administration with TCRVP+ T cell depletion (BJM1117) over a 26-day period. FIG. 76C shows tumor volume (mm3) following BNM1007 (mouse surrogate for BNM0800) administration alone, or BNM1007 (mouse surrogate for BNM0800) administration with TCRVP+ T cell depletion over a 26- day period. FIG. 76D shows percent tumor growth inhibition (TGI) following BNM1007 (mouse surrogate for BNM0800) administration alone, or BNM1007 (mouse surrogate for BNM0800) administration with TCRVP+ T cell depletion (BJM1117) over a 26-day period.

[0354] FIG. 77A - FIG. 77D show the magnitude of T cell activation as a function of exemplary molecule administration over a 120-hour period in a non-human primate (NHP) model. FIG. 77A shows the percentage of activated (i.e., CD25+) T cells over time in NHP donor VL324. FIG. 77B shows the percentage of activated (i.e., CD25+) T cells overtime in NHP donor FR1502. FIG. 77C shows the number of CD8+, CD25+ cells over time in NHP donor VL324. FIG. 77D shows the number of CD8+, CD25+ cells over time in NHP donor VL324.

[0355] FIG. 78 shows the concentration of exemplary molecules administered at different doses (0.03, 0.1, 1, or 3 mpk) in a non-human primate model over a 168-hour period.

[0356] FIG. 79A and FIG. 79B show sCD25 upregulation in response to administration of ascending doses (0.03, 0.1, 1, or 3 mpk) of exemplary molecules over a 168-hour period in a non-human primate model. FIG. 79A shows sCD25 concentration (pM) following administration of exemplary molecule BOM0076. FIG. 79B shows sCD25 concentration (pM) following administration of exemplary molecule BNM0800.

[0357] FIG. 80A and FIG. 80B show serum CRP concentration (mg / dL) in response to administration of ascending doses (0.03, 0.1, 1, or 3 mpk) of exemplary molecules over a 984-hour period in a non- human primate model. FIG. 80A shows CRP levels following administration of exemplary molecule BOM0076. FIG. 80B shows CRP levels following administration of exemplary molecule BNM0800.DETAILED DESCRIPTIONDEFINITION

[0358] Certain specific details of this description are set forth in order to provide a thorough understanding of various embodiments. However, one skilled in the art will understand that the present disclosure may be practiced without these details. In other instances, well-known structures have not been shown or described in detail to avoid unnecessarily obscuring descriptions of the embodiments.

[0359] Unless the context requires otherwise, throughout the specification and claims which follow, the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in anWSGR Docket No. 53676-759.601 open, inclusive sense, that is, as “including, but not limited to.” Further, headings provided herein are for convenience only and do not interpret the scope or meaning of the claimed disclosure.

[0360] As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the content clearly dictates otherwise. The use of the words “a” or “an” when used in conjunction with the term “comprising” herein may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.”

[0361] It should also be noted that the term “or” is generally employed in its sense including “and / or” unless the content clearly dictates otherwise.

[0362] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present disclosure, suitable methods and materials are described below.

[0363] The term “about” when referring to a measurable value such as an amount, a temporal duration, and the like, is meant to encompass variations of ±20% or in some instances ±10%, or in some instances ±5%, or in some instances ±1%, or in some instances ±0.1% from the specified value, as such variations are appropriate to perform the disclosed methods. As used herein, “about” and “approximately” generally mean an acceptable degree of error for the quantity measured given the nature or precision of the measurements. Exemplary degrees of error are within 20 percent (%), typically, within 10%, and more typically, within 5% of a given range of values.

[0364] The term “acquire” or “acquiring” as the terms are used herein, refer to obtaining possession of a physical entity (e.g. , a sample, a polypeptide, a nucleic acid, or a sequence), or a value, e.g. , a numerical value, by “directly acquiring” or “indirectly acquiring” the physical entity or value. “Directly acquiring” means performing a process (e.g., performing a synthetic or analytical method) to obtain the physical entity or value. “Indirectly acquiring” refers to receiving the physical entity or value from another party or source (e.g. , a third party laboratory that directly acquired the physical entity or value). Directly acquiring a physical entity includes performing a process that includes a physical change in a physical substance, e.g., a starting material. Directly acquiring a value includes performing a process that includes a physical change in a sample or another substance, e.g., performing an analytical process which includes a physical change in a substance, e.g., a sample.

[0365] “Antibody molecule” as used herein refers to a protein, e.g., an immunoglobulin chain or fragment thereof, comprising at least one immunoglobulin variable domain structure and / or sequence. An antibody molecule encompasses antibodies (e.g., full-length antibodies) and antibody fragments. In some embodiments, an antibody molecule comprises an antigen binding or functional fragment of a full length antibody, or a full length immunoglobulin chain. For example, a full-length antibody is an immunoglobulin (Ig) molecule (e.g., an IgG antibody) that is naturally occurring or formed by normal immunoglobulin gene fragment recombinatorial processes). In embodiments, an antibody molecule refers to an immunologically active, antigen-binding portion of an immunoglobulin molecule, such as an antibody fragment. An antibody fragment, e.g., functional fragment, is a portion of an antibody, e.g., Fab,WSGR Docket No. 53676-759.601Fab', F(ab')2, F(ab)2, variable fragment (Fv), domain antibody (dAb), or single chain variable fragment (scFv). A functional antibody fragment binds to the same antigen as that recognized by the intact (e.g., full-length) antibody. The terms “antibody fragment” or “functional fragment” also include isolated fragments consisting of the variable regions, such as the “Fv” fragments consisting of the variable regions of the heavy and light chains or recombinant single chain polypeptide molecules in which light and heavy variable regions are connected by a peptide linker (“scFv proteins”). In some embodiments, an antibody fragment does not include portions of antibodies without antigen binding activity, such as Fc fragments or single amino acid residues. Exemplary antibody molecules include full length antibodies and antibody fragments, e.g, dAb (domain antibody), single chain, Fab, Fab’, and F(ab’)2 fragments, and single chain variable fragments (scFvs). In some embodiments, the antibody molecule is an antibody mimetic. In some embodiments, the antibody molecule is, or comprises, an antibody-like framework or scaffold, such as, fibronectins, ankyrin repeats (e.g., designed ankyrin repeat proteins (DARPins)), avimers, affibody affinity ligands, anti calins, or affilin molecules.

[0366] The term “human-like antibody molecule” as used herein refers to a humanized antibody molecule, human antibody molecule or an antibody molecule having at least 95% sequence identity with a non-murine germline framework region, e.g., FR1, FR2, FR3 and / or FR4. In some embodiments, the human-like antibody molecule comprises a framework region having at least 95% sequence identity to a human germline framework region, e.g., a FR1, FR2, FR3 and / or FR4 of a human germline framework region. In some embodiments, the human-like antibody molecule is a recombinant antibody. In some embodiments, the human-like antibody molecule is a humanized antibody molecule. In some embodiments, the human-like antibody molecule is human antibody molecule. In some embodiments, the human-like antibody molecule is a phage display or a yeast display antibody molecule. In some embodiments, the human-like antibody molecule is a chimeric antibody molecule. In some embodiments, the human-like antibody molecule is a CDR grafted antibody molecule.

[0367] As used herein, an “immunoglobulin variable domain sequence” refers to an amino acid sequence which can form the structure of an immunoglobulin variable domain. For example, the sequence may include all or part of the amino acid sequence of a naturally-occurring variable domain. For example, the sequence may or may not include one, two, or more N- or C-terminal amino acids, or may include other alterations that are compatible with formation of the protein structure.

[0368] In embodiments, an antibody molecule is monospecific, e.g., it comprises binding specificity for a single epitope. In some embodiments, an antibody molecule is multispecific, e.g., it comprises a plurality of immunoglobulin variable domain sequences, where a first immunoglobulin variable domain sequence has binding specificity for a first epitope and a second immunoglobulin variable domain sequence has binding specificity for a second epitope. In some embodiments, an antibody molecule is a bispecific antibody molecule. “Bispecific antibody molecule” as used herein refers to an antibody molecule that has specificity for more than one (e.g. , two, three, four, or more) epitope and / or antigen.

[0369] “Antigen” (Ag) as used herein refers to a molecule that can provoke an immune response, e.g., involving activation of certain immune cells and / or antibody generation. Any macromolecule, includingWSGR Docket No. 53676-759.601 almost all proteins or peptides, can be an antigen. Antigens can also be derived from genomic recombinant or DNA. For example, any DNA comprising a nucleotide sequence or a partial nucleotide sequence that encodes a protein capable of eliciting an immune response encodes an “antigen.” In embodiments, an antigen does not need to be encoded solely by a full length nucleotide sequence of a gene, nor does an antigen need to be encoded by a gene at all. In embodiments, an antigen can be synthesized or can be derived from a biological sample, e.g. , a tissue sample, a tumor sample, a cell, or a fluid with other biological components. As used, herein a “tumor antigen” or interchangeably, a “cancer antigen” includes any molecule present on, or associated with, a cancer, e.g., a cancer cell or a tumor microenvironment that can provoke an immune response. As used, herein an “immune cell antigen” includes any molecule present on, or associated with, an immune cell that can provoke an immune response.

[0370] The “antigen-binding site,” or “binding portion” of an antibody molecule refers to the part of an antibody molecule, e.g., an immunoglobulin (Ig) molecule, that participates in antigen binding. In embodiments, the antigen binding site is formed by amino acid residues of the variable (V) regions of the heavy (H) and light (L) chains. Three highly divergent stretches within the variable regions of the heavy and light chains, referred to as hypervariable regions, are disposed between more conserved flanking stretches called “framework regions,” (FRs). FRs are amino acid sequences that are naturally found between, and adjacent to, hypervariable regions in immunoglobulins. In embodiments, in an antibody molecule, the three hypervariable regions of a light chain and the three hypervariable regions of a heavy chain are disposed relative to each other in three dimensional space to form an antigen-binding surface, which is complementary to the three-dimensional surface of a bound antigen. The three hypervariable regions of each of the heavy and light chains are referred to as “complementarity-determining regions,” or “CDRs.” The framework region and CDRs have been defined and described, e.g., in Kabat, E.A., et al. (1991) Sequences of Proteins of Immunological Interest, Fifth Edition, U.S. Department of Health and Human Services, NIH Publication No. 91-3242, and Chothia, C. et al. (1987) J. Mol. Biol. 196:901-917. Each variable chain (e.g., variable heavy chain and variable light chain) is typically made up of three CDRs and four FRs, arranged from amino-terminus to carboxy-terminus in the amino acid order: FR1, CDR1, FR2, CDR2, FR3, CDR3, and FR4.

[0371] As used herein, an “immune cell” refers to any of various cells that function in the immune system, e.g., to protect against agents of infection and foreign matter. In embodiments, this term includes leukocytes, e.g., neutrophils, eosinophils, basophils, lymphocytes, and monocytes. Innate leukocytes include phagocytes (e.g., macrophages, neutrophils, and dendritic cells), mast cells, eosinophils, basophils, and natural killer cells. Innate leukocytes identify and eliminate pathogens, either by attacking larger pathogens through contact or by engulfing and then killing microorganisms, and are mediators in the activation of an adaptive immune response. The cells of the adaptive immune system are special types of leukocytes, called lymphocytes. B cells and T cells are important types of lymphocytes and are derived from hematopoietic stem cells in the bone marrow. B cells are involved in the humoral immuneWSGR Docket No. 53676-759.601 response, whereas T cells are involved in cell-mediated immune response. The term “immune cell” includes immune effector cells.

[0372] ‘ ‘Immune effector cell,” as that term is used herein, refers to a cell that is involved in an immune response, e.g., in the promotion of an immune effector response. Examples of immune effector cells include, but are not limited to, T cells, e.g., alpha / beta T cells and gamma / delta T cells, B cells, natural killer (NK) cells, natural killer T (NK T) cells, and mast cells.

[0373] The term “effector function” or “effector response” refers to a specialized function of a cell. Effector function of a T cell, for example, may be cytolytic activity or helper activity including the secretion of cytokines.

[0374] The terms “polypeptide”, “peptide” and “protein” (if single chain) are used interchangeably herein to refer to polymers of amino acids of any length. The polymer may be linear or branched, it may comprise modified amino acids, and it may be interrupted by non-amino acids. The terms also encompass an amino acid polymer that has been modified; for example, disulfide bond formation, glycosylation, lipidation, acetylation, phosphorylation, or any other manipulation, such as conjugation with a labeling component. The polypeptide can be isolated from natural sources, can be a produced by recombinant techniques from a eukaryotic or prokaryotic host, or can be a product of synthetic procedures.

[0375] The terms “nucleic acid,” “nucleic acid sequence,” “nucleotide sequence,” or “polynucleotide sequence,” and “polynucleotide” are used interchangeably. They refer to a polymeric form of nucleotides of any length, either deoxyribonucleotides or ribonucleotides, or analogs thereof. The polynucleotide may be either single-stranded or double -stranded, and if single -stranded may be the coding strand or noncoding (antisense) strand. A polynucleotide may comprise modified nucleotides, such as methylated nucleotides and nucleotide analogs. The sequence of nucleotides may be interrupted by non-nucleotide components. A polynucleotide may be further modified after polymerization, such as by conjugation with a labeling component. The nucleic acid may be a recombinant polynucleotide, or a polynucleotide of genomic, cDNA, semisynthetic, or synthetic origin which either does not occur in nature or is linked to another polynucleotide in a non-natural arrangement.

[0376] The term “isolated,” as used herein, refers to material that is removed from its original or native environment (e.g., the natural environment if it is naturally occurring). For example, a naturally- occurring polynucleotide or polypeptide present in a living animal is not isolated, but the same polynucleotide or polypeptide, separated by human intervention from some or all of the co-existing materials in the natural system, is isolated. Such polynucleotides could be part of a vector and / or such polynucleotides or polypeptides could be part of a composition, and still be isolated in that such vector or composition is not part of the environment in which it is found in nature. An isolated polynucleotide (ribonucleic acid (RNA), deoxyribonucleic acid (DNA)), or polypeptide is free of the genes / nucleic acids or sequence s / amino acids that flank it in its naturally-occurring state.

[0377] The compositions and methods of the present invention encompass polypeptides and nucleic acids having the sequences specified, or sequences substantially identical or similar thereto, e.g., sequences at least 80%, 85%, 90%, 95% identical or higher to the sequence specified. In the context of anWSGR Docket No. 53676-759.601 amino acid sequence, the term “substantially identical” is used herein to refer to a first amino acid that contains a sufficient or minimum number of amino acid residues that are i) identical to, or ii) conservative substitutions of aligned amino acid residues in a second amino acid sequence such that the first and second amino acid sequences can have a common structural domain and / or common functional activity. For example, amino acid sequences that contain a common structural domain having at least about 80%, 85%, 90%. 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% 99%, 99.5%, 99.9%, or 100% sequence identity to a reference sequence, e.g., a sequence provided herein. In the context of nucleotide sequence, the term “substantially identical” is used herein to refer to a first nucleic acid sequence that contains a sufficient or minimum number of nucleotides that are identical to aligned nucleotides in a second nucleic acid sequence such that the first and second nucleotide sequences encode a polypeptide having common functional activity, or encode a common structural polypeptide domain or a common functional polypeptide activity. For example, nucleotide sequences having at least about 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% 99%, 99.5%, 99.9%, or 100% sequence identity to a reference sequence, e.g., a sequence provided herein.

[0378] The term “variant” refers to a polypeptide that has a substantially identical amino acid sequence to a reference amino acid sequence, or is encoded by a substantially identical nucleotide sequence. In some embodiments, the variant is a functional variant. In some embodiments, a TCRJ3V variant can bind to TCRa and form a TCR a: [3 complex. In some embodiments, a TCRaV variant can bind to TCRa and form a TCR a: [3 complex.

[0379] The term “functional variant” refers to a polypeptide that has a substantially identical amino acid sequence to a reference amino acid sequence, or is encoded by a substantially identical nucleotide sequence, and is capable of having one or more activities of the reference amino acid sequence.

[0380] Calculations of homology or sequence identity between sequences (the terms are used interchangeably herein) are performed as follows. To determine the percent identity of two amino acid sequences, or of two nucleic acid sequences, the sequences are aligned for optimal comparison purposes (e.g. , gaps can be introduced in one or both of a first and a second amino acid or nucleic acid sequence for optimal alignment and non-homologous sequences can be disregarded for comparison purposes). In a preferred embodiment, the length of a reference sequence aligned for comparison purposes is at least 30%, preferably at least 40%, more preferably at least 50%, 60%, and even more preferably at least 70%, 80%, 90%, 100% of the length of the reference sequence. The amino acid residues or nucleotides at corresponding amino acid positions or nucleotide positions are then compared. When a position in the first sequence is occupied by the same amino acid residue or nucleotide as the corresponding position in the second sequence, then the molecules are identical at that position (as used herein amino acid or nucleic acid “identity” is equivalent to amino acid or nucleic acid “homology”).

[0381] The percent identity between the two sequences is a function of the number of identical positions shared by the sequences, taking into account the number of gaps, and the length of each gap, which need to be introduced for optimal alignment of the two sequences. The comparison of sequences and determination of percent identity between two sequences can be accomplished using a mathematicalWSGR Docket No. 53676-759.601 algorithm. In a preferred embodiment, the percent identity between two amino acid sequences is determined using the Needleman and Wunsch ((1970) J. Mol. Biol. 48:444-453 ) algorithm which has been incorporated into the GAP program in the GCG software package (available at http: / / www.gcg.com), using either a Blossum 62 matrix or a PAM250 matrix, and a gap weight of 16, 14, 12, 10, 8, 6, or 4 and a length weight of 1, 2, 3, 4, 5, or 6. In yet another preferred embodiment, the percent identity between two nucleotide sequences is determined using the GAP program in the GCG software package (available at http: / / www.gcg.com), using a NWSgapdna.CMP matrix and a gap weight of 40, 50, 60, 70, or 80 and a length weight of 1, 2, 3, 4, 5, or 6. A particularly preferred set of parameters (and the one that should be used unless otherwise specified) are a Blossum 62 scoring matrix with a gap penalty of 12, a gap extend penalty of 4, and a frameshift gap penalty of 5.

[0382] The percent identity between two amino acid or nucleotide sequences can be determined using the algorithm of E. Meyers and W. Miller ((1989) CABIOS, 4: 11-17) which has been incorporated into the ALIGN program (version 2.0), using a PAM120 weight residue table, a gap length penalty of 12 and a gap penalty of 4. The nucleic acid and protein sequences described herein can be used as a “query sequence” to perform a search against public databases to, for example, identify other family members or related sequences. Such searches can be performed using the NBLAST and XBLAST programs (version 2.0) of Altschul, et al. (1990) J. Mol. Biol. 215:403-10. BLAST nucleotide searches can be performed with the NBLAST program, score = 100, wordlength = 12 to obtain nucleotide sequences homologous to a nucleic acid molecule of the invention. BLAST protein searches can be performed with the XBLAST program, score = 50, wordlength = 3 to obtain amino acid sequences homologous to protein molecules of the invention. To obtain gapped alignments for comparison purposes, Gapped BLAST can be utilized as described in Altschul et al., (1997) Nucleic Acids Res. 25:3389-3402. When utilizing BLAST and Gapped BLAST programs, the default parameters of the respective programs (e.g., XBLAST and NBLAST) can be used.

[0383] It is understood that the molecules of the present invention may have additional conservative or non-essential amino acid substitutions, which do not have a substantial effect on their functions.

[0384] The term “amino acid” is intended to embrace all molecules, whether natural or synthetic, which include both an amino functionality and an acid functionality and capable of being included in a polymer of naturally-occurring amino acids. Exemplary amino acids include naturally-occurring amino acids; analogs, derivatives and congeners thereof; amino acid analogs having variant side chains; and all stereoisomers of any of any of the foregoing. As used herein the term “amino acid” includes both the D- or L- optical isomers and peptidomimetics.

[0385] A ‘ ‘conservative amino acid substitution” is one in which the amino acid residue is replaced with an amino acid residue having a similar side chain. Eamilies of amino acid residues having similar side chains have been defined in the art. These families include amino acids with basic side chains (e.g., lysine, arginine, histidine), acidic side chains (e.g., aspartic acid, glutamic acid), uncharged polar side chains (e.g., glycine, asparagine, glutamine, serine, threonine, tyrosine, cysteine), nonpolar side chains (e.g., alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, tryptophan), beta-branchedWSGR Docket No. 53676-759.601 side chains (e.g., threonine, valine, isoleucine) and aromatic side chains (e.g., tyrosine, phenylalanine, tryptophan, histidine).

[0386] As used herein, the term “molecule” as used in, e.g., antibody molecule, cytokine molecule, receptor molecule, includes full-length, naturally-occurring molecules, as well as variants, e.g., functional variants (e.g., truncations, fragments, mutated (e.g., substantially similar sequences) or derivatized form thereof), so long as at least one function and / or activity of the unmodified (e.g., naturally-occurring) molecule remains.

[0387] As used herein, the term “mutation” refers to an alteration in the nucleotide sequence of the genome of an organism, virus, or extrachromosomal DNA. In some embodiments, the mutation may be a large-scale mutation, such as amplifications (or gene duplications) or repetitions of a chromosomal segment, deletions of large chromosomal regions, chromosomal rearrangements (e.g., chromosomal translocations, chromosomal inversions, non-homologous chromosomal crossover, and interstitial deletions), and loss of heterozygosity. In some embodiments, the mutation may be a small-scale mutation, such as insertions, deletions, and substitution mutations. As used herein, the term “substitution mutation” refers to the transition that exchange a single nucleotide for another.

[0388] “Interleukin-21” also known as IL21, IL-21, IL 21, Zal 1, CVID11, and interleukin 21, as referred to herein, includes any of the recombinant or naturally-occurring forms of IL-21 or variants or homologs thereof that have or maintain IL-21 activity (e.g., at least 40% 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99% or 100% activity). In some aspects, the variants or homologs have at least 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% amino acid sequence identity across the whole sequence or a portion of the sequence (e.g., a 50, 100, 150 or 200 continuous amino acid portion) compared to a naturally occurring IL-21. In some embodiments, IL-21 is substantially identical to the protein identified by the UniProt reference number Q9HBE4 or a variant or homolog having substantial identity thereto.

[0389] The term “co-stimulatory receptor,” as used herein, refers to the cell surface molecules that can positively induce a secondary signal to fully activate T cells with TCR signaling and cytokine stimulation. In some embodiments, exemplary co-stimulatory receptors include, but are not limited to, CD2, CD27, CD28, ICOS (CD278), 4-1BB (CD137), 0X40 (CD134), CD40, CD40L, Toll-like receptors (TLRs), or any combination thereof.IL-21 mutein or IL-21 fusion compositions

[0390] Provided herein is a composition comprising a IL-21 polypeptide, a IL-21 mutein, a IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises a sequence of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises a IL-21 wild type polypeptide. In some embodiments, the IL-21 wild type polypeptide comprises a sequence of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide,WSGR Docket No. 53676-759.601 the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises a IL-21 mutein polypeptide, such as a IL-21 mutein polypeptide provided herein. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises a IL-21 fusion polypeptide, such as a IL-21 mutein polypeptide provided herein.

[0391] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises a sequence having at least 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100% sequence identity to any one of the sequences listed in Tables 21, 23, 24, or 26.

[0392] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises a sequence having at least 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100% sequence identity to SEQ ID NO:2193.

[0393] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises a sequence having at least 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100% sequence identity to any one sequence selected from the group consisting of SEQ ID N0s:5000-5036.

[0394] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises a sequence having at least 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100% sequence identity to SEQ ID NO:5052.

[0395] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises a sequence having at least 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100% sequence identity to SEQ ID NO:5054.

[0396] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises any one sequence selected from the group consisting of SEQ ID NOs: 5000-5036.

[0397] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises a sequence of SEQ ID NO:5052.

[0398] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises a sequence of SEQ ID NO:5054.

[0399] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL- 21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises anWSGR Docket No. 53676-759.601 aromatic amino acid substitution of He at position 8 of SEQ ID NO: 2193. In some embodiments, the IL- 21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an aromatic amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe or Trp. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an aromatic amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe. In some embodiments, the IL- 21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an aromatic amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp.

[0400] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Lys. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with His. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Tyr.

[0401] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with His. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution ofLys at position 77 of SEQ ID NO: 2193 with Asn. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution ofLys at position 77 of SEQ ID NO: 2193 with Gin. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Thr.

[0402] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, theWSGR Docket No. 53676-759.601IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu.

[0403] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu.

[0404] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu.

[0405] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193 with Thr.

[0406] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193 with Gly.

[0407] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of His at position 120 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp.

[0408] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Leu at position 123 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Leu at position 123 of SEQ ID NO: 2193 with Thr.

[0409] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Arg at position 11 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Arg at position 11 of SEQ ID NO: 2193 with Ala.WSGR Docket No. 53676-759.601

[0410] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Gin at position 12 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Gin at position 12 of SEQ ID NO: 2193 with His.

[0411] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Gin at position 19 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Gin at position 19 of SEQ ID NO: 2193 with Asn.

[0412] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 66 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL- 21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 66 of SEQ ID NO: 2193 with Phe.

[0413] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Lys at position 72 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Lys at position 72 of SEQ ID NO: 2193 with Ser.

[0414] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Ser at position 80 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Ser at position 80 of SEQ ID NO: 2193 with His. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Ser at position 80 of SEQ ID NO: 2193 with Asn. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Ser at position 80 of SEQ ID NO: 2193 with Thr.

[0415] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 and an amino acid substitution of His at position 120 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an aromatic amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp and an aromatic amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp.WSGR Docket No. 53676-759.601

[0416] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 and an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe, and an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Lys.

[0417] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193, an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193, an amino acid substitution of His at position 120 of SEQ ID NO: 2193, or any combination thereof. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193, an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193, and an amino acid substitution of His at position 120 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193 with Thr, an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp, or any combination thereof. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193 with Thr, and an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp.

[0418] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193, or any combination thereof. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193.

[0419] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, or any combination thereof. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of ArgWSGR Docket No. 53676-759.601 at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu.

[0420] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193, an amino acid substitution of His at position 120 of SEQ ID NO: 2193, or any combination thereof. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193, and an amino acid substitution of His at position 120 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193 with Gly, an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp, or any combination thereof.Jn some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193 with Gly, and an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp.

[0421] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193, an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, or any combination thereof. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193, an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu. In some embodiments, the IL-21WSGR Docket No. 53676-759.601 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe, an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Lys, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, or any combination thereof. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe, an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Lys, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu.

[0422] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193, an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193, an amino acid substitution of His at position 120 of SEQ ID NO: 2193, an amino acid substitution of Leu at position 123 of SEQ ID NO: 2193, or any combination thereof. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193, an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193, an amino acid substitution of His at position 120 of SEQ ID NO: 2193, and an amino acid substitution of Leu at position 123 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193 with Thr, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193 with Gly, an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp, an amino acid substitution of Leu at position 123 of SEQ ID NO: 2193 with Thr, or any combination thereof. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193 with Thr, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg atWSGR Docket No. 53676-759.601 position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193 with Gly, an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp, and an amino acid substitution of Leu at position 123 of SEQ ID NO: 2193 with Thr.

[0423] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193, an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193, an amino acid substitution of His at position 120 of SEQ ID NO: 2193, or any combination thereof. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193, an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193, and an amino acid substitution of His at position 120 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp, or any combination thereof.Jn some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO : 2193 with Trp, an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp.

[0424] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193, an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193, an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193, or any combination thereof. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193, an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193,WSGR Docket No. 53676-759.601 an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe, an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Lys, an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, or any combination thereof. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe, an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Lys, an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu.

[0425] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193, an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193, an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193, an amino acid substitution of His at position 120 of SEQ ID NO: 2193, an amino acid substitution of Leu at position 123 of SEQ ID NO: 2193, or any combination thereof. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193, an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193, an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193, an amino acid substitution of His at position 120 of SEQ ID NO: 2193, and an amino acid substitution of Leu at position 123 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193 with Thr, an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ IDWSGR Docket No. 53676-759.601NO: 2193 with Glu, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193 with Gly, an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp, an amino acid substitution of Leu at position 123 of SEQ ID NO: 2193 with Thr, or any combination thereof. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193 with Thr, an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193 with Gly, an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp, and an amino acid substitution of Leu at position 123 of SEQ ID NO: 2193 with Thr,

[0426] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193, or any combination thereof. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, or any combination thereof. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu.

[0427] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein comprises an IL-4 sequence or a fragment thereof. In some embodiments, the IL-4 sequence or a fragment thereof comprises having at least 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100% sequence identity to SEQ ID NO:5037. In some embodiment, the IL-4 sequence or a fragment thereof comprises a sequence of SEQ ID NO: 5037. In some embodiments, the IL-4 sequence or a fragment thereof comprises having at least 30%, 35%, 40%,WSGR Docket No. 53676-759.60145%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100% sequence identity to SEQ ID NO: 5053. In some embodiment, the IL-4 sequence or a fragment thereof comprises a sequence of SEQ ID NO: 5053.

[0428] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein is a fusion peptide. In specific embodiments, the fusion peptide comprises IL-21 polypeptide sequence or a fragment thereof fused to an IL-4 sequence or a fragment thereof. In more specific embodiments, the fusion peptide comprises a sequence having at least 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100% sequence identity to the sequence of SEQ ID NO: 5052 operatively linked to a sequence having at least 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100% sequence identity to the sequence of SEQ ID NO: 5053 operatively linked to a sequence having at least 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100% sequence identity to the sequence of SEQ ID NO: 5054. In more specific embodiments, the fusion peptide comprises a sequence of SEQ ID NO: 5052 operatively linked to a sequence of SEQ ID NO: 5053 operatively linked to a sequence of SEQ ID NO: 5054.

[0429] Provided in an aspect is a polynucleotide encoding the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein. In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein is produced in a higher amount than a IL-21 wild type polypeptide (being encoded by a corresponding polynucleotide) when expressed in a cell (for example, under otherwise identical conditions). In some embodiments, the full length of the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein is produced in a higher amount than the full length of the IL-21 wild type polypeptide (being encoded by a corresponding polynucleotide) when expressed in a cell (for example, under otherwise identical conditions). In some embodiments, the full length of the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein relative to fragments thereof is produced in a higher ratio than the full length of the IL-21 wild type polypeptide relative to fragments thereof (being encoded by a corresponding polynucleotide) when expressed in a cell (for example, under otherwise identical conditions).

[0430] In some embodiments, when a polynucleotide comprising a sequence encoding the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein is expressed in a cell, the ratio of the amount of a full-length the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein produced to the amount of a less than full-length the IL-21 polypeptide, the IL-21 mutein, the IL- 21 fusion polypeptide, or a functional fragment or variant thereof as described herein produced is higher than the ratio of the amount of a corresponding full length IL-21 wild-type polypeptide produced to theWSGR Docket No. 53676-759.601 amount of a less than full-length IL-21 wild-type polypeptide produced when a polynucleotide comprising a sequence encoding a IL-21 wild-type polypeptide is expressed in a cell.

[0431] In some embodiments, the ratio of the amount of a full-length the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein produced to the amount of a less than full-length the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein produced when expressed in a cell is at least 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 150%, 200%, 250%, 300%, 350%, 400%, 450%, 500%, 550%, 600%, 650%, 700%, 750%, 800%, 850%, 900%, 950%, 1000%, 2000%, 3000%, 4000%, 5000%, 6000%, 7000%, 8000%, 9000%, 10000%, 11000%, 12000%, 13000%, 14000%, 15000%, 16000%, 17000%, 18000%, 19000%, or 20000% higher than the ratio of the amount of corresponding a full length IL-21 wild-type polypeptide produced to the amount of a less than full-length IL-21 wild-type polypeptide produced when expressed in a cell (for example, under otherwise identical conditions).

[0432] In some embodiments, the ratio of the amount of a full-length the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein produced to the amount of a less than full-length the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein produced when expressed in a cell is at least 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, or 1000 fold than the ratio of the amount of corresponding a full length IL-21 wild-type polypeptide produced to the amount of a less than full-length IL-21 wild-type polypeptide produced when expressed in a cell (for example, under otherwise identical conditions).

[0433] In some embodiments, the amount of a full-length the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein produced is at least 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 150%, 200%, 250%, 300%, 350%, 400%, 450%, 500%, 550%, 600%, 650%, 700%, 750%, 800%, 850%, 900%, 950%, 1000%, 2000%, 3000%, 4000%, 5000%, 6000%, 7000%, 8000%, 9000%, 10000%, 11000%, 12000%, 13000%, 14000%, 15000%, 16000%, 17000%, 18000%, 19000%, or 20000% higher than the amount of a corresponding full length IL-21 wild-type polypeptide when the polynucleotide comprising a sequence encoding the IL-21 wild-type polypeptide is expressed in a cell (for example, under otherwise identical conditions).

[0434] In some embodiments, the amount of a full-length the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein produced is at least 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, or 1000 fold higher than the amount of a corresponding full length IL-21WSGR Docket No. 53676-759.601 wild-type polypeptide when the polynucleotide comprising a sequence encoding the IL-21 wild-type polypeptide is expressed in a cell (for example, under otherwise identical conditions).

[0435] In some embodiments, when a polynucleotide comprising a sequence encoding the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein is expressed in a cell, the amount of the full-length IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein produced is higher than the amount of the corresponding full-length IL-21 wild-type polypeptide produced when the polynucleotide comprising a sequence encoding the IL-21 wild-type polypeptide is expressed in a cell.

[0436] In some embodiments, when a polynucleotide comprising a sequence encoding the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein is expressed in a cell, the ratio of the amount of a full-length IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein produced to the amount of a less than full-length IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein produced is higher than the ratio of the amount of a corresponding full length IL-21 wild-type polypeptide produced to the amount of a less than full-length IL-21 wild-type polypeptide produced when a polynucleotide comprising a sequence encoding a IL-21 wild-type polypeptide is expressed in a cell, and the amount of the full-length IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein produced is higher than the amount of the corresponding full-length IL-21 wild-type polypeptide produced when the polynucleotide comprising a sequence encoding the IL-21 wild-type polypeptide is expressed in a cell.

[0437] In some embodiments, provided herein is a IL-21 polypeptide, a IL-21 mutein, a IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein that is less susceptible to proteolytic cleavage compared to a corresponding IL-21 wild-type polypeptide. In some embodiments, provided herein is a IL-21 polypeptide, a IL-21 mutein, a IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein that is less susceptible to proteolytic cleavage when expressed in a cell compared to a corresponding IL-21 wild-type polypeptide when expressed in a cell.

[0438] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein is at least 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% less susceptible to proteolytic cleavage compared to a corresponding IL-21 wild-type polypeptide.

[0439] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein is at least 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% less susceptible to proteolytic cleavage when expressed in a cell compared to a corresponding IL-21 wild-type polypeptide when expressed in a cell.WSGR Docket No. 53676-759.601

[0440] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein is at least 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% less susceptible to proteolytic cleavage compared to a corresponding IL-21 wild-type polypeptide.

[0441] In some embodiments, the IL-21 polypeptide, the IL-21 mutein, the IL-21 fusion polypeptide, or a functional fragment or variant thereof as described herein is at least 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, or 1000 fold less susceptible to proteolytic cleavage when expressed in a cell compared to a corresponding IL-21 wild-type polypeptide when expressed in a cell.

[0442] In some embodiments, the activity of an IL-21 mutein is enhanced and / or prolonged by introducing an aromatic amino acid substitution of He at position 8 of SEQ ID NO: 2193 to an IL-21 mutein polypeptide compared to an IL-21 wild-type or variant polypeptide without the aromatic amino acid substitution of He at position 8 of SEQ ID NO: 2193 by at least 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, or 1000 fold.

[0443] In some embodiments, the activity of an IL-21 mutein is enhanced and / or prolonged by introducing an aromatic amino acid substitution of He at position 8 of SEQ ID NO: 2193 to an IL-21 mutein polypeptide compared to an IL-21 wild-type or variant polypeptide without the aromatic amino acid substitution of He at position 8 of SEQ ID NO: 2193 by at least at least 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 150%, 200%, 250%, 300%, 350%, 400%, 450%, 500%, 550%, 600%, 650%, 700%, 750%, 800%, 850%, 900%, 950%, 1000%, 2000%, 3000%, 4000%, 5000%, 6000%, 7000%, 8000%, 9000%, 10000%, 11000%, 12000%, 13000%, 14000%, 15000%, 16000%, 17000%, 18000%, 19000%, or 20000% fold.Anti-TCRBV antibodiesHuman T cell receptor (TCR) complex

[0444] TCR is a disulfide-linked membrane -anchored heterodimeric protein normally consisting of the highly variable alpha (a) and beta (P) chains expressed as part of a complex with the invariant CD3 chain molecules. TCR on a T cells is formed by a heterodimer of one alpha chain and one beta chain. Each alpha or beta chain consists of a constant domain and a highly variable domain classified as the Immunoglobulin superfamily (IgSF) fold. The TCRpV chains can be further classified into 30 subfamilies (TRBV1-30). Despite their high structural and functional homology, the amino acid sequence homology in the TRBV genes is very low. Only 4 amino acids out of approximately 95 are identical while 10 additional amino acids are conserved among all subfamilies (see, an alignment of TCRBV amino acid sequences in Table 9). Nevertheless, TCRs formed between alpha and beta chains of highlyWSGR Docket No. 53676-759.601 diverse sequences show a remarkable structural homology (FIGs. 5A and 5B) and elicit a similar function, e.g., activation of T cells.

[0445] T cell receptors (TCR) can be found on the surface of T cells. TCRs recognize antigens, e.g., peptides, presented on, e.g., bound to, major histocompatibility complex (MHC) molecules on the surface of cells, e.g, antigen-presenting cells. TCRs are heterodimeric molecules and can comprise an alpha chain, a beta chain, a gamma chain or a delta chain. TCRs comprising an alpha chain and a beta chain are also referred to as TCRap. The TCR beta chain consists of the following regions (also known as segments): variable (V), diversity (D), joining (J) and constant (C) (see Mayer G. and Nyland J. (2010) Chapter 10: Major Histocompatibility Complex and T-cell Receptors-Role in Immune Responses. In: Microbiology and Immunology on-line, University of South Carolina School of Medicine). The TCR alpha chain consists of V, J and C regions. The rearrangement of the T-cell receptor (TCR) through somatic recombination of V (variable), D (diversity), J (joining), and C (constant) regions is a defining event in the development and maturation of a T cell. TCR gene rearrangement takes place in the thymus.

[0446] TCRs can comprise a receptor complex, known as the TCR complex, which comprises a TCR heterodimer comprising of an alpha chain and a beta chain, and dimeric signaling molecules, e.g., CD3 co-receptors, e.g., CD3o / s. and / or CD3y / a.

[0447] As used herein, the term “T cell receptor beta variable chain” or “TCRpV,” refers to an extracellular region of the T cell receptor beta chain which comprises the antigen recognition domain of the T cell receptor. The term TCRpV includes isoforms, mammalian, e.g., human TCRpV, species homologs of human and analogs comprising at least one common epitope with TCRpV. Human TCRpV comprises a gene family comprising subfamilies including, but not limited to: a TCRP V6 subfamily, a TCRP V10 subfamily, a TCRP V12 subfamily, a TCRP V5 subfamily, a TCRP V7 subfamily, a TCRP VI 1 subfamily, a TCRP V14 subfamily, a TCRP V16 subfamily, a TCRP V18 subfamily, a TCRP V9 subfamily, a TCRP V13 subfamily, a TCRP V4 subfamily, a TCRP V3 subfamily, a TCRP V2 subfamily, a TCRP V15 subfamily, a TCRP V30 subfamily, a TCRP V19 subfamily, a TCRP V27 subfamily, a TCRP V28 subfamily, a TCRP V24 subfamily, a TCRP V20 subfamily, TCRP V25 subfamily, a TCRP V29 subfamily, a TCRP VI subfamily, a TCRP VI 7 subfamily, a TCRP V21 subfamily, a TCRP V23 subfamily, or a TCRP V26 subfamily, as well as family members of said subfamilies, and variants thereof (e.g., a structural or functional variant thereof). In some embodiments, the TCRP V6 subfamily comprises: TCRP V6-4*01, TCRP V6-4*02, TCRP V6-9*01, TCRP V6-8*01, TCRP V6-5*01, TCRP V6-6*02, TCRP V6-6*01, TCRP V6-2*01, TCRP V6-3*01 or TCRP V6-l*01. In some embodiments, TCRpV comprises TCRP V6-5*01, or a variant thereof, e.g., a variant having 85%, 90%, 95%, 99% or more identity the naturally-occurring sequence. TCRP V6-5*01 is also known as TRBV65; TCRBV6S5; TCRBV13S1, or TCRP V13.1. The amino acid sequence of TCRP V6-5*01, e.g., human TCRP V6-5*01, is known in that art, e.g., as provided by IMGT ID L36092. In some embodiments, TCRP V6-5*01 is encoded by the nucleic acid sequence of SEQ ID NO: 43, or a sequence having 85%, 90%, 95%, 99% or more identity thereof. In some embodiments, TCRP V6-5*01 comprises the amino acid sequence of SEQ ID NO: 44, or a sequence having 85%, 90%, 95%, 99% or more identity thereof.WSGR Docket No. 53676-759.601

[0448] SEQ ID NO: 43ATGAGCATCGGCCTCCTGTGCTGTGCAGCCTTGTCTCTCCTGTGGGCAGGTCCAGTGAATGC TGGTGTCACTCAGACCCCAAAATTCCAGGTCCTGAAGACAGGACAGAGCATGACACTGCAG TGTGCCCAGGATATGAACCATGAATACATGTCCTGGTATCGACAAGACCCAGGCATGGGGC TGAGGCTGATTCATTACTCAGTTGGTGCTGGTATCACTGACCAAGGAGAAGTCCCCAATGGC TACAATGTCTCCAGATCAACCACAGAGGATTTCCCGCTCAGGCTGCTGTCGGCTGCTCCCTC CCAGACATCTGTGTACTTCTGTGCCAGCAGTTACTC

[0449] SEQ ID NO: 44MSIGLLCCAALSLLWAGPVNAGVTQTPKFQVLKTGQSMTLQCAQDMNHEYMSWYRQDPGMG LRLIHY-SVGAGITDQGEVPNGYNVSRSTTEDFPLRLLSAAPSQTSVYFCASSYTCR beta V (TCRRV)

[0450] Diversity in the immune system enables protection against a huge array of pathogens. Since the germline genome is limited in size, diversity is achieved not only by the process of V(D)J recombination but also by junctional (junctions between V-D and D-J segments) deletion of nucleotides and addition of pseudo-random, non-templated nucleotides. The TCR beta gene undergoes gene arrangement to generate diversity.

[0451] The TCR V beta repertoire varies between individuals and populations because of, e.g., 7 frequently occurring inactivating polymorphisms in functional gene segments and a large insertion / deletion -related polymorphism encompassing 2 V beta gene segments.

[0452] Provided herein are, inter alia, antibody molecules and fragments thereof, that bind, e.g., specifically bind, to a human TCR beta V chain (TCRpV), e.g. , a TCRJ3V gene family (also referred to as a group), e.g. , a TCRJ3V subfamily (also referred to as a subgroup), e.g. , as described herein. TCR beta V families and subfamilies are known in the art, e.g., as described in Yassai et al., (2009) Immunogenetics 61(7)pp:493-502; Wei S. and Concannon P. (1994) Human Immunology 41(3) pp: 201-206. The antibodies described herein can be recombinant antibodies, e.g., recombinant non-murine antibodies, e.g., recombinant human or humanized antibodies.

[0453] The terms TCRBV, TCRVB, TRBV, TCRpV, TCRVp or TRpV are used interchangeably herein and refer to a TCR beta V chain, e.g., as described herein.

[0454] In some embodiments, provided herein is an anti-TCRpV antibody molecule that binds to human TCRPV, e.g. , a TCRpV family, e.g. , gene family or a variant thereof. In some embodiments a TCRBV gene family comprises one or more subfamilies, e.g., as described herein, e.g., in FIG. 4, Table 8A or Table 8B. In some embodiments, the TCRpV gene family comprises: a TCRP V6 subfamily, a TCRP V10 subfamily, a TCRP V12 subfamily, a TCRP V5 subfamily, a TCRP V7 subfamily, a TCRP VI 1 subfamily, a TCRP V14 subfamily, a TCRP V16 subfamily, a TCRP V18 subfamily, a TCRP V9 subfamily, a TCRP V13 subfamily, a TCRP V4 subfamily, a TCRP V3 subfamily, a TCRP V2 subfamily, a TCRP V15 subfamily, a TCRP V30 subfamily, a TCRP V19 subfamily, a TCRP V27 subfamily, a TCRP V28 subfamily, a TCRP V24 subfamily, a TCRP V20 subfamily, TCRP V25 subfamily, a TCRPWSGR Docket No. 53676-759.601V29 subfamily, a TCRP VI subfamily, a TCRP VI 7 subfamily, a TCRP V21 subfamily, a TCRP V23 subfamily, or a TCRP V26 subfamily.

[0455] In some embodiments, TCRP V6 subfamily is also known as TCRP V13.1. In some embodiments, the TCRP V6 subfamily comprises: TCRP V6-4*01, TCRP V6-4*02, TCRP V6-9*01, TCRP V6-8*01, TCRP V6-5*01, TCRP V6-6*02, TCRP V6-6*01, TCRP V6-2*01, TCRP V6-3*01 or TCRP V6-l*01, or a variant thereof. In some embodiments, TCRP V6 comprises TCRP V6-4*01, or a variant thereof. In some embodiments, TCRP V6 comprises TCRP V6-4*02, or a variant thereof. In some embodiments, TCRP V6 comprises TCRP V6-9*01, or a variant thereof. In some embodiments, TCRP V6 comprises TCRP V6-8*01, or a variant thereof. In some embodiments, TCRP V6 comprises TCRP V6-5*01, or a variant thereof. In some embodiments, TCRP V6 comprises TCRP V6-6*02, or a variant thereof. In some embodiments, TCRP V6 comprises TCRP V6-6*01, or a variant thereof. In some embodiments, TCRP V6 comprises TCRP V6-2*01, or a variant thereof. In some embodiments, TCRP V6 comprises TCRP V6-3*01, or a variant thereof. In some embodiments, TCRP V6 comprises TCRP V6-l*01, or a variant thereof.

[0456] In some embodiments, TCRP V6 comprises TCRP V6-5*01, or a variant thereof. In some embodiments, TCRP V6, e.g., TCRP V6-5*01, is recognized, e.g., bound, by SEQ ID NO: 1 and / or SEQ ID NO: 2. In some embodiments, TCRP V6, e.g., TCRP V6-5*01, is recognized, e.g., bound, by SEQ ID NO: 9 and / or SEQ ID NO: 10. In some embodiments, TCRP V6 is recognized, e.g., bound, by SEQ ID NO: 9 and / or SEQ ID NO: 11.

[0457] In some embodiments, TCRP V10 subfamily is also known as TCRP V12. In some embodiments, the TCRP V10 subfamily comprises: TCRP V10-l*01, TCRP V10-l*02, TCRP V10-3*01 or TCRP V10-2*01, or a variant thereof.

[0458] In some embodiments, TCRP V12 subfamily is also known as TCRP V8.1. In some embodiments, the TCRP V12 subfamily comprises: TCRP V12-4*01, TCRP V12-3*01, or TCRP V12- 5*01, or a variant thereof. In some embodiments, TCRP V12 is recognized, e.g., bound, by SEQ ID NO: 15 and / or SEQ ID NO: 16. In some embodiments, TCRP V12 is recognized, e.g., bound, by any one of SEQ ID NOs 23-25, and / or any one of SEQ ID NO: 26-30:

[0459] In some embodiments, the TCRP V5 subfamily is chosen from: TCRP V5-5*01, TCRP V5-6*01, TCRP V5-4*01, TCRP V5-8*01, TCRP V5-l*01, or a variant thereof.

[0460] In some embodiments, the TCRP V7 subfamily comprises TCRP V7-7*01, TCRP V7-6*01, TCRP V7 -8*02, TCRP V7 -4*01, TCRP V7-2*02, TCRP V7-2*03, TCRP V7-2*01, TCRP V7-3*01, TCRP V7-9*03, or TCRP V7-9*01, or a variant thereof.

[0461] In some embodiments, the TCRP VI 1 subfamily comprises: TCRP VI 1-1*01, TCRP VI 1-2*01 or TCRP Vl l-3*01, or a variant thereof. In some embodiments, the TCRP V14 subfamily comprises TCRP V14*01, or a variant thereof. In some embodiments, the TCRP V16 subfamily comprises TCRP V16*01, or a variant thereof. In some embodiments, the TCRP VI 8 subfamily comprises TCRP VI 8*01, or a variant thereof. In some embodiments, the TCRP V9 subfamily comprises TCRP V9*01 or TCRP V9*02, or a variant thereof. In some embodiments, the TCRP V13 subfamily comprises TCRP V13*01,WSGR Docket No. 53676-759.601 or a variant thereof. In some embodiments, the TCRP V4 subfamily comprises TCRP V4-2*01, TCRP V4-3*01, or TCRP V4-l*01, or a variant thereof. In some embodiments, the TCRP V3 subfamily comprises TCRP V3-l*01, or a variant thereof. In some embodiments, the TCRP V2 subfamily comprises TCRP V2*01, or a variant thereof. In some embodiments, the TCRP V15 subfamily comprises TCRP V15*01, or a variant thereof. In some embodiments, the TCRP V30 subfamily comprises TCRP V30*01, or TCRP V30*02, or a variant thereof. In some embodiments, the TCRP V19 subfamily comprises TCRP V19*01, or TCRP V19*02, or a variant thereof. In some embodiments, the TCRP V27 subfamily comprises TCRP V27*01, or a variant thereof. In some embodiments, the TCRP V28 subfamily comprises TCRP V28*01, or a variant thereof. In some embodiments, the TCRP V24 subfamily comprises TCRP V24-l*01, or a variant thereof. In some embodiments, the TCRP V20 subfamily comprises TCRP V20-l*01, or TCRP V20-l*02, or a variant thereof. In some embodiments, the TCRP V25 subfamily comprises TCRP V25-l*01, or a variant thereof. In some embodiments, the TCRP V29 subfamily comprises TCRP V29-l*01, or a variant thereof.

[0462] Exemplary amino acid sequences for TCRpV subfamily members can be found on the ImMunoGeneTics Information System website: http: / / www.imgt.org / , or in a similar resource.Anti-TCRBV antibodies

[0463] Current bispecific constructs designed to redirect T cells to promote tumor cell lysis for cancer immunotherapy typically utilize antibody fragments (Fab, scFv, VH, single domain antibody, etc.) that are derived from monoclonal antibodies (mAb) directed against the CD3e subunit of the T cell receptor (TCR). However, there are limitations to this approach which may prevent the full realization of the therapeutic potential for such bispecific constructs. Previous studies have shown that even low “activating” doses of anti-CD3e mAb can cause long-term T cell dysfunction and exert immunosuppressive effects. In addition, anti-CD3e mAbs have been associated with side effects that result from massive T cell activation. The large number of activated T cells secrete substantial amounts of cytokines, the most important of which is Interferon gamma (IFNy). This excess amount of IFNy in turn activates macrophages which then overproduce proinflammatory cytokines such as IL-lbeta, IL-6, IL- 10 and TNF-alpha, causing a “cytokine storm” known as the cytokine release syndrome (CRS) (Shimabukuro-Vomhagen et al., J Immunother Cancer. 2018 Jun 15 ;6( 1) :56, herein incorporated by reference in its entirety). Thus, the need exists for developing antibodies that are capable of binding and activating only a subset of effector T cells, e.g., to re-duce the CRS and / or neurotoxicity (NT).

[0464] Described herein are molecules targeting the TCRpV chain of TCR and methods thereof. Without wishing to be bound by theory, such molecules are capable of binding, activating, and / or expanding only a subset of T cells, avoiding or reducing CRS and / or NT and minimizing potential immunosuppressive effects of anti-CD3 mAbs.

[0465] Described herein is a class of antibodies, i.e., anti-TCRpV antibody molecules as described herein, which despite having low sequence similarity (e.g., low sequence identity among the different antibody molecules that recognize different TCRpV subfamilies), recognize a structurally conserved, yetWSGR Docket No. 53676-759.601 sequence-wise variable, region, e.g., domain, on the TCRpV protein (as denoted by the circled area in FIG. 5 A) and have a similar function (e.g., activation of T cells and a similar cytokine profde as described herein). Thus, the anti-TCRpV antibody molecules as described herein share a structurefunction relationship.

[0466] Without wishing to be bound by theory, in some embodiments, the anti-TCRpV antibody molecules as described herein bind to an outward facing epitope of a TCRpV protein when it is in a complex with a TCRalpha protein, e.g., as denoted by the circled area in FIG. 5A. In some embodiments, the anti-TCRpV antibody molecules as described herein recognize (e.g., bind to), a domain (e.g., an epitope) on the TCRpV protein that is: (1) structurally conserved among different TCRpV subfamilies; and (2) has minimal sequence identity among the different TCRpV subfamilies. As shown in Table 9, TCRpV proteins from the different TCRBV subfamilies share minimal sequence similarity. However, as shown in FIG. 5A-5B, TCRpV proteins which have minimal sequence similarity, share a similar 3D conformation and structure.

[0467] The alignment of TCRBV amino acid sequences in Table 9 underscores the diversity of TCR sequences. In particular, the TRBV sequences from different subfamilies are considerably different from each other.

[0468] In some embodiments, the anti-TCRpV antibody molecules as described herein do not recognize, e.g., bind to, an interface of a TCRpV: TCRalpha complex. In some embodiments, the anti-TCRpV antibody molecules as described herein do not recognize, e.g., bind to, a constant region of a TCRpV protein. An exemplary antibody that binds to a constant region of a TCRBV region is JOVI. 1 as described in Viney et al., (Hybridoma. 1992 Dec;l 1 (6) : 701 - 13) . In some embodiments, the anti-TCRpV antibody molecules as described herein do not recognize, e.g., bind to, one or more (e.g., all) of a complementarity determining region (e.g., CDR1, CDR2 and / or CDR3) of a TCRpV protein.

[0469] Provided herein are, inter alia, antibody molecules directed to the variable chain of the beta subunit of TCR (TCRpV) which bind and, e.g., activate a subset of T cells. The anti-TCRpV antibody molecules as described herein result in lesser or no production of cytokines associated with CRS, e.g., IL- 6, IL-lbeta, IL- 10 and TNF alpha; and enhanced and / or delayed production of IL-2 and IFNy. In some embodiments, the anti-TCRpV antibodies as described herein have a cytokine profile, e.g., as described herein, which differs from a cytokine profile of a T cell engager that binds to a receptor or molecule other than a TCRpV region (“a non-TCRpV-binding T cell engager”). In some embodiments, the non-TCRpV- binding T cell engager comprises an antibody that binds to a CD3 molecule (e.g., CD3 epsilon (CD3e) molecule). In some embodiments, the non-TCRpV-binding T cell engager is an OKT3 antibody or an SP34-2 antibody.

[0470] In some embodiments, the anti-TCRpV antibodies as described herein result in expansion of TCRPV+ T cells, e.g., a subset of memory effector T cells known as TEMRA. Without wishing to be bound by theory, it is believed that in some embodiments, TEMRA cells can promote tumor cell lysis but not CRS. Accordingly, provided herein are methods of making said anti-TCRpV antibody molecules and uses thereof. Also described herein are multispecific molecules, e.g., bispecific molecules comprisingWSGR Docket No. 53676-759.601 said anti-TCRpV antibody molecules. In some embodiments, compositions comprising anti-TCRpV antibody molecules of the present disclosure, can be used, e.g., to: (1) activate and redirect T cells to promote tumor cell lysis for cancer immuno-therapy; and / or (2) expand TCRPV+ T cells. In some embodiments, compositions comprising anti-TCRpV antibody molecules as described herein limit the harmful side-effects of CRS and / or NT, e.g., CRS and / or NT associated with anti-CD3e targeting.

[0471] In some embodiments, the anti-TCRpV antibody molecule binds to one or more of TRBV2, TRBV3-1, TRBV4-1, TRBV4-2, TRBV4-3, TRBV5-1, TRBV5-4, TRBV5-5, TRBV5-6, TRBV5-8, TRBV6-1, TRBV6-2, TRBV6-3, TRBV6-4, TRBV6-5, TRBV6-6, TRBV6-8, TRBV6-9, TRBV7-2, TRBV7-3, TRBV7-4, TRBV7-6, TRBV7-7, TRBV7-8, TRBV7-9, TRBV9, TRBV10-1, TRBV10-2, TRBV10-3, TRBV11-1, TRBV11-2, TRBV11-3, TRBV12-3, TRBV12-4, TRBV12-5, TRBV13, TRBV14, TRBV15, TRBV16, TRBV18, TRBV19, TRBV20-1, TRBV24-1, TRBV25-1, TRBV27, TRBV28, TRBV29-1 and TRBV30. In some embodiments, the anti-TCRpV antibody molecule binds to one or more of TRBV6-1, TRBV6-2, TRBV6-3, TRBV6-4, TRBV6-5, TRBV6-6, TRBV6-8 and TRBV6-9. In some embodiments, the anti-TCRpV antibody molecule is an anti-TRBV2, anti-TRBV3-l, anti-TRBV4-l, anti-TRBV4-2, anti-TRBV4-3, anti-TRBV5-l, anti-TRBV5-4, anti-TRBV5-5, anti- TRBV5-6, anti-TRBV5-8, anti-TRBV6-l, anti-TRBV6-2, anti-TRBV6-3, anti-TRBV6-4, anti-TRBV6-5, anti-TRBV6-6, anti-TRBV6-8, anti-TRBV6-9, anti-TRBV7-2, anti-TRBV7-3, anti-TRBV7-4, anti- TRBV7-6, anti-TRBV7-7, anti-TRBV7-8, anti-TRBV7-9, anti-TRBV9, anti-TRBVl 0-1, anti-TRBVlO- 2, anti-TRBVl 0-3, anti-TRBVl 1-1, anti-TRBVl 1-2, anti-TRBVl 1-3, anti-TRBV12-3, anti-TRBV12-4, anti-TRBV12-5, anti-TRBV13, anti-TRBV14, anti-TRBV15, anti-TRBV16, anti-TRBV18, anti- TRBV19, anti-TRBV20-l, anti-TRBV24-l, anti-TRBV25-l, anti-TRBV27, anti-TRBV28, anti- TRBV29-1, or anti-TRBV30. Exemplary anti-TCRpV antibody molecules and the corresponding TCRpV subfamilies recognized by said anti-TCRpV antibody molecules are disclosed in Table 10.

[0472] In some embodiments, the anti-TCRpV antibody molecule binds specifically to TRBV2, TRBV3-1, TRBV4-1, TRBV4-2, TRBV4-3, TRBV5-1, TRBV5-4, TRBV5-5, TRBV5-6, TRBV5-8, TRBV6-1, TRBV6-2, TRBV6-3, TRBV6-4, TRBV6-5, TRBV6-6, TRBV6-8, TRBV6-9, TRBV7-2, TRBV7-3, TRBV7-4, TRBV7-6, TRBV7-7, TRBV7-8, TRBV7-9, TRBV9, TRBV10-1, TRBV10-2, TRBV10-3, TRBV11-1, TRBV11-2, TRBV11-3, TRBV12-3, TRBV12-4, TRBV12-5, TRBV13, TRBV14, TRBV15, TRBV16, TRBV18, TRBV19, TRBV20-1, TRBV24-1, TRBV25-1, TRBV27, TRBV28, TRBV29-1 or TRBV30. In some embodiments, the anti-TCRpV antibody molecule binds specifically to TRBV6-1. In some embodiments, the anti-TCRpV antibody molecule binds specifically to TRBV6-2. In some embodiments, the anti-TCRpV antibody molecule binds specifically to TRBV6-3. In some embodiments, the anti-TCRpV antibody molecule binds specifically to TRBV6-4. In some embodiments, the anti-TCRpV antibody molecule binds specifically to TRBV6-5. In some embodiments, the anti-TCRpV antibody molecule binds specifically to TRBV6-6. In some embodiments, the anti- TCRpV antibody molecule binds specifically to TRBV6-8. In some embodiments, the anti-TCRpV antibody molecule binds specifically to TRBV6-9.WSGR Docket No. 53676-759.601

[0473] In some embodiments, the anti-TCRpV antibody molecule does not bind to TCRP V12, or binds to TCR[3 V12 with an affinity and / or binding specificity that is less than (e.g., less than about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or about 2-, 5-, or 10- fold) the affinity and / or binding specificity of the 16G8 murine antibody or a humanized version thereof as de-scribed in US Patent 5,861,155.

[0474] In some embodiments, the anti-TCRpV antibody molecule binds to TCRP V12 with an affinity and / or binding specificity that is greater than (e.g., greater than about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or about 2-, 5-, or 10- fold) the affinity and / or binding specificity of the 16G8 murine antibody or a humanized version thereof as described in US Patent 5,861,155.

[0475] In some embodiments, the anti-TCRpV antibody molecule binds to a TCRpV region other than TCRP V12 (e.g., TCRpV region as described herein, e.g., TCRP V6 subfamily (e.g., TCRP V6-5*01) with an affinity and / or binding specificity that is greater than (e.g., greater than about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or about 2-, 5-, or 10- fold) the affinity and / or binding specificity of the 16G8 murine antibody or a humanized version thereof as de-scribed in US Patent 5,861,155.

[0476] In some embodiments, the anti-TCRpV antibody molecule does not comprise the CDRs of the Antibody B murine antibody.

[0477] In some embodiments, the anti-TCRpV antibody molecule does not bind to TCRP V5-5*01 or TCRP V5-l*01, or binds to TCRP V5-5*01 or TCRP V5-l*01 with an affinity and / or binding specificity that is less than (e.g., less than about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or about 2-, 5-, or 10- fold) the affinity and / or binding specificity of the TM23 murine antibody or a humanized version thereof as described in US Patent 5,861,155.

[0478] In some embodiments, the anti-TCRpV antibody molecule binds to TCRP V5-5*01 or TCRP V5- l*01with an affinity and / or binding specificity that is greater than (e.g., greater than about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or about 2-, 5-, or 10- fold) the affinity and / or binding specificity of the TM23 murine antibody or a humanized version thereof as de-scribed in US Patent 5,861,155.

[0479] In some embodiments, the anti-TCRpV antibody molecule binds to a TCRpV region other than TCRP V5-5*01 or TCRP V5-l*01 (e.g., TCRpV region as described herein, e.g., TCRP V6 subfamily (e.g., TCRP V6-5*01) with an affinity and / or binding specificity that is greater than (e.g., greater than about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or about 2-, 5-, or 10- fold) the affinity and / or binding specificity of the TM23 murine antibody or a humanized version thereof as described in US Patent 5,861,155.

[0480] In some embodiments, the anti-TCRpV antibody molecule does not comprise the CDRs of the TM23 murine antibody.

[0481] In some embodiments, the light or the heavy chain variable framework (e.g., the region encompassing at least FR1, FR2, FR3, and optionally FR4) of the anti-TCRpV antibody molecule, e.g., anti -TCRP V6 (e.g., anti-TCRp V6-5*01) antibody molecule can be chosen from: (a) a light or heavy chain variable framework including at least 80%, 85%, 87% 90%, 92%, 93%, 95%, 97%, 98%, or 100% of the amino acid residues from a human light or heavy chain variable framework, e.g. , a light or heavy chain variable framework residue from a human mature antibody, a human germline sequence, or aWSGR Docket No. 53676-759.601 human consensus sequence; (b) a light or heavy chain variable framework including from 20% to 80%, 40% to 60%, 60% to 90%, or 70% to 95% of the amino acid residues from a human light or heavy chain variable framework, e.g., a light or heavy chain variable framework residue from a human mature antibody, a human germline sequence, or a human consensus sequence; (c) a non-human framework (e.g. , a rodent framework); or (d) a non-human framework that has been modified, e.g. , to remove antigenic or cytotoxic determinants, e.g, deimmunized, or partially humanized. In some embodiments, the light or heavy chain variable framework region (particularly FR1, FR2 and / or FR3) includes a light or heavy chain variable framework sequence at least 70, 75, 80, 85, 87, 88, 90, 92, 94, 95, 96, 97, 98, 99% identical or identical to the frameworks of a VL or VH segment of a human germline gene.

[0482] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises a heavy chain variable domain having at least one, two, three, four, five, six, seven, ten, fifteen, twenty or more changes, e.g, amino acid substitutions or deletions, from an amino acid sequence of any one of A-H. 1 to A-H.85, e.g., A-H.1, A-H.2 or A-H.68, e.g., the amino acid sequence of the FR region in the entire variable region, e.g., shown in FIG. 2A, or in SEQ ID NO: 9.

[0483] Alternatively, or in combination with the heavy chain substitutions described herein, the anti- TCRJ3V antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises a light chain variable domain having at least one, two, three, four, five, six, seven, ten, fifteen, twenty or more amino acid changes, e.g., amino acid substitutions or deletions, from an amino acid sequence of any one of A-H.1 to A-H.85, e.g., A-H. 1, A-H.2 or A-H.68, e.g. , the amino acid sequence of the FR region in the entire variable region, e.g., shown in FIG. 2B, or in SEQ ID NO: 10 or SEQ ID NO: 11.

[0484] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, includes one, two, three, or four heavy chain framework regions shown in FIG. 2A, or a sequence substantially identical thereto.

[0485] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, includes one, two, three, or four light chain framework regions shown in FIG. 2B, or a sequence substantially identical thereto.

[0486] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises the light chain framework region 1 of A-H.l or A-H.2, e.g., as shown in FIG. 2B.

[0487] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises the light chain framework region 2 of A-H.l or A-H.2, e.g., as shown in FIG. 2B.

[0488] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises the light chain framework region 3 of A-H.l or A-H.2, e.g., as shown in FIG. 2B.WSGR Docket No. 53676-759.601

[0489] In some embodiments, the anti-TCR[3V antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises the light chain framework region 4 of A-H.l or A-H.2, e.g., as shown in FIG. 2B.

[0490] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises a light chain variable domain comprising a framework region, e.g., framework region 1 (FR1), comprising a change, e.g., a substitution (e.g., a conservative substitution) at position 10 according to Kabat numbering. In some embodiments, the FR1 comprises a Phenylalanine at position 10, e.g., a Serine to Phenylalanine substitution. In some embodiments, the substitution is relative to a human germline light chain framework region sequence.

[0491] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises a light chain variable domain comprising a framework region, e.g., framework region 2 (FR2), comprising a change, e.g., a substitution (e.g., a conservative substitution) at a position as described herein according to Kabat numbering. In some embodiments, FR2 comprises a Histidine at position 36, e.g., a substitution at position 36 according to Kabat numbering, e.g., a Tyrosine to Histidine substitution. In some embodiments, FR2 comprises an Alanine at position 46, e.g., a substitution at position 46 according to Kabat numbering, e.g., an Arginine to Alanine substitution. In some embodiments, the substitution is relative to a human germline light chain framework region sequence.

[0492] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises a light chain variable domain comprising a framework region, e.g., framework region 3 (FR3), comprising a change, e.g., a substitution (e.g., a conservative substitution) at a position as described herein according to Kabat numbering. In some embodiments, FR3 comprises a Phenylalanine at position 87, e.g., a substitution at position 87 according to Kabat numbering, e.g., a Tyrosine to Phenylalanine substitution. In some embodiments, the substitution is relative to a human germline light chain framework region sequence.

[0493] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises a light chain variable domain comprising: (a) a framework region 1 (FR1) comprising a Phenylalanine at position 10, e.g., a substitution at position 10 according to Kabat numbering, e.g., a Serine to Phenylalanine substitution; (b) a framework region 2 (FR2) comprising a Histidine at position 36, e.g., a substitution at position 36 according to Kabat numbering, e.g., a Tyrosine to Histidine substitution, and a Alanine at position 46, e.g., a substitution at position 46 according to Kabat numbering, e.g., a Arginine to Alanine substitution; and (c) a framework region 3 (FR3) comprising a Phenylalanine at position 87, e.g., a substitution at position 87 according to Kabat numbering, e.g., a Tyrosine to Phenylalanine substitution, e.g., as shown in the amino acid sequence of SEQ ID NO: 10. In some embodiments, the substitution is relative to a human germline light chain framework region sequence.

[0494] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises a light chain variable domain comprising: (a) a frameworkWSGR Docket No. 53676-759.601 region 2 (FR2) comprising a Histidine at position 36, e.g., a substitution at position 36 according to Kabat numbering, e.g., a Tyrosine to Histidine substitution, and a Alanine at position 46, e.g, a substitution at position 46 according to Kabat numbering, e.g., a Arginine to Alanine substitution; and (b) a framework region 3 (FR3) comprising a Phenylalanine at position 87, e.g., a substitution at position 87 according to Kabat numbering, e.g., a Tyrosine to Phenylalanine substitution, e.g., as shown in the amino acid sequence of SEQ ID NO: 11. In some embodiments, the substitution is relative to a human germline light chain framework region sequence.

[0495] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises a light chain variable domain comprising: (a) a framework region 1 (FR1) comprising a change, e.g., a substitution (e.g., a conservative substitution) at one or more (e.g., all) positions as described herein according to Kabat numbering,; (b) a framework region 2 (FR2) comprising a change, e.g., a substitution (e.g., a conservative substitution) at one or more (e.g., all) position as described herein according to Kabat numbering and (c) a framework region 3 (FR3) comprising a change, e.g., a substitution (e.g., a conservative substitution) at one or more (e.g., all) position as described herein according to Kabat numbering. In some embodiments, the substitution is relative to a human germline light chain framework region sequence.

[0496] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises the heavy chain framework region 1 of A-H.l or A-H.2, e.g., as shown in FIG. 2A. In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises the heavy chain framework region 2 of A-H.1 or A- H.2, e.g., as shown in FIG. 2A. In some embodiments, the anti-TCRpV antibody molecule, e.g., anti- TCRP V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises the heavy chain framework region 3 of A-H.l or A-H.2, e.g., as shown in FIG. 2A. In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises the heavy chain framework region 4 of A-H.1 or A-H.2, e.g. , as shown in FIG. 2A.

[0497] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises a heavy chain variable domain comprising a framework region, e.g., framework region 3 (FR3), comprising a change, e.g., a substitution (e.g., a conservative substitution) at a position as described herein according to Kabat numbering. In some embodiments, FR3 comprises a Threonine at position 73, e.g., a substitution at position 73 according to Kabat numbering, e.g., a Glutamic Acid to Threonine substitution. In some embodiments, FR3 comprises a Glycine at position 94, e.g., a substitution at position 94 according to Kabat numbering, e.g., an Arginine to Glycine substitution. In some embodiments, the substitution is relative to a human germline heavy chain framework region sequence.

[0498] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises a heavy chain variable domain comprising a framework region 3 (FR3) comprising a Threonine at position 73, e.g., a substitution at position 73 according to Kabat numbering, e.g., a Glutamic Acid to Threonine substitution, and a Glycine at position 94, e.g., aWSGR Docket No. 53676-759.601 substitution at position 94 according to Kabat numbering, e.g., a Arginine to Glycine substitution, e.g., as shown in the amino acid sequence of SEQ ID NO: 10.

[0499] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises the heavy chain framework regions 1-4 of A-H. 1 or A-H.2, e.g., SEQ ID NO: 9, or as shown in FIGs. 2A and 2B. In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises the light chain framework regions 1-4 of A-H.l, e.g., SEQ ID NO: 10, or as shown in FIGs. 2A and 2B. In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises the light chain framework regions 1-4 of A-H.2, e.g., SEQ ID NO: 11, or as shown in FIGs. 2A and 2B. In some embodiments, the anti-TCRpV antibody molecule, e.g., anti- TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises the heavy chain framework regions 1-4 of A-H. 1, e.g., SEQ ID NO: 9; and the light chain framework regions 1-4 of A-H. 1, e.g., SEQ ID NO: 10, or as shown in FIGs. 2A and 2B. In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises the heavy chain framework regions 1-4 of A-H.2, e.g., SEQ ID NO: 9; and the light chain framework regions 1-4 of A-H.2, e.g., SEQ ID NO: 11, or as shown in FIGs. 2A and 2B.

[0500] In some embodiments, the heavy or light chain variable domain, or both, of the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, includes an amino acid sequence, which is substantially identical to an amino acid as described herein, e.g., at least 80%, 85%, 90%, 92%, 95%, 97%, 98%, 99% or higher identical to a variable region of an antibody described herein, e.g. , an antibody chosen from any one of A-H. 1 to A-H.85, e.g., A-H.1, A-H.2 or A-H.68, or as described in Table 1, or encoded by the nucleotide sequence in Table 1; or which differs at least 1 or 5 residues, but less than 40, 30, 20, or 10 residues, from a variable region of an antibody described herein.

[0501] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises at least one, two, three, or four antigen-binding regions, e.g., variable regions, having an amino acid sequence as set forth in Table 1, or a sequence substantially identical thereto (e.g., a sequence at least about 85%, 90%, 95%, 99% or more identical thereto, or which differs by no more than 1, 2, 5, 10, or 15 amino acid residues from the sequences shown in Table 1. In another embodiment, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule includes a VH and / or VL domain encoded by a nucleic acid having a nucleotide sequence as set forth in Table 1, or a sequence substantially identical thereto (e.g., a sequence at least about 85%, 90%, 95%, 99% or more identical thereto, or which differs by no more than 3, 6, 15, 30, or 45 nucleotides from the sequences shown in Table 1.

[0502] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises: a VH domain comprising the amino acid sequence of SEQ ID NO: 9, an amino acid sequence at least about 85%, 90%, 95%, 99% or more identical to the amino acid sequence of SEQ ID NO: 9, or an amino acid sequence which differs by no more than 1, 2, 5, 10, or 15 amino acid residues from the amino acid sequence of SEQ ID NO: 9; and / or a VL domain comprising theWSGR Docket No. 53676-759.601 amino acid sequence of SEQ ID NO: 10, an amino acid sequence at least about 85%, 90%, 95%, 99% or more identical to the amino acid sequence of SEQ ID NO: 10, or an amino acid sequence which differs by no more than 1, 2, 5, 10, or 15 amino acid residues from the amino acid sequence of SEQ ID NO: 10.

[0503] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises: a VH domain comprising the amino acid sequence of SEQ ID NO: 9, an amino acid sequence at least about 85%, 90%, 95%, 99% or more identical to the amino acid sequence of SEQ ID NO: 9, or an amino acid sequence which differs by no more than 1, 2, 5, 10, or 15 amino acid residues from the amino acid sequence of SEQ ID NO: 9; and / or a VL domain comprising the amino acid sequence of SEQ ID NO: 11, an amino acid sequence at least about 85%, 90%, 95%, 99% or more identical to the amino acid sequence of SEQ ID NO: 11, or an amino acid sequence which differs by no more than 1, 2, 5, 10, or 15 amino acid residues from the amino acid sequence of SEQ ID NO: 11.

[0504] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule is a full antibody or fragment thereof (e.g., a Fab, F(ab')2, Fv, single domain antibody, or a single chain Fv fragment (scFv)). In embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCR[3 V6 (e.g., anti-TCRp V6-5*01) antibody molecule is a monoclonal antibody or an antibody with single specificity. In some embodiments, the anti-TCRpV antibody molecule, e.g., anti- TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, can also be a humanized, chimeric, camelid, shark, or an in w / ro-gcncratcd antibody molecule. In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, is a humanized antibody molecule. The heavy and light chains of the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, can be full-length (e.g, an antibody can include at least one, and preferably two, complete heavy chains, and at least one, and preferably two, complete light chains) or can include an antigen-binding fragment (e.g, a Fab, F(ab')2, Fv, a single chain Fv fragment, a single domain antibody, a diabody (dAb), a bivalent antibody, or bispecific antibody or fragment thereof, a single domain variant thereof, a VHH, or a camelid antibody).

[0505] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, is in the form of a multispecific molecule, e.g, a bispecific molecule, e.g., as described herein.

[0506] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, has a heavy chain constant region (Fc) chosen from, e.g., the heavy chain constant regions of IgGl, IgG2, IgG3, IgG4, IgM, IgAl, IgA2, IgD, and IgE. In some embodiments, the Fc region is chosen from the heavy chain constant regions of IgGl, IgG2, IgG3, and IgG4. In some embodiments, the Fc region is chosen from the heavy chain constant region of IgGl or IgG2 (e.g., human IgGl, or IgG2). In some embodiments, the heavy chain constant region is human IgGl. In some embodiments, the Fc region comprises a Fc region variant, e.g., as described herein.

[0507] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, has a light chain constant region chosen from, e.g., the light chain constant regions of kappa or lambda, preferably kappa (e.g., human kappa). In some embodiments, the constantWSGR Docket No. 53676-759.601 region is altered, e.g., mutated, to modify the properties of the anti-TCR V antibody molecule, e.g., anti- TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule (e.g, to increase or decrease one or more of: Fc receptor binding, antibody glycosylation, the number of cysteine residues, effector cell function, or complement function). For example, the constant region is mutated at positions 296 (M to Y), 298 (S to T), 300 (T to E), 477 (H to K) and 478 (N to F) to alter Fc receptor binding (e.g. , the mutated positions correspond to positions 132 (M to Y), 134 (S to T), 136 (T to E), 313 (H to K) and 314 (N to F) of SEQ ID NOs: 212 or 214; or positions 135 (M to Y), 137 (S to T), 139 (T to E), 316 (H to K) and 317 (N to F) of SEQ ID NOs: 215, 216, 217 or 218), e.g., relative to human IgGl.

[0508] Antibody A-H. 1 comprises a heavy chain comprising the amino acid sequence of SEQ ID NO: 3278 and a light chain comprising the amino acid sequence of SEQ ID NO: 72. Antibody A-H.2 comprises a heavy chain comprising the amino acid sequence of SEQ ID NO: 3278 and a light chain comprising the amino acid sequence of SEQ ID NO: 3279. Antibody A-H.68 comprises the amino acid sequence of SEQ ID NO: 1337, or a sequence having at least 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or 100% sequence identity thereto. Antibody A-H.69 comprises the amino acid sequence of SEQ ID NO: 1500, or a sequence having at least 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or 100% sequence identity thereto.

[0509] Additional exemplary humanized anti-TCRB V6 antibodies are provided in Table 1. In some embodiments, the anti-TCRp V6 is antibody A, e.g., humanized antibody A (antibody A-H), as provided in Table 1 . In some embodiments, the anti-TCRpV antibody comprises one or more (e.g., all three) of a LC CDR1, LC CDR2, and LC CDR3 provided in Table 1; and / or one or more (e.g., all three) of a HC CDR1, HC CDR2, and HC CDR3 provided in Table 1, or a sequence with at least 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or 100% sequence identity thereto. In some embodiments, antibody A comprises a variable heavy chain (VH) and / or a variable light chain (VL) provided in Table 1, or a sequence with at least 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or 100% sequence identity thereto.

[0510] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule comprises a VH of A-H. 1, A-H.2, A-H.3, A-H.4, A-H.5, A-H.6, A-H.7, A- H.8, A-H.9, A-H.10, A-H. l l, A-H.12, A-H.13, A-H.14, A-H.15, A-H.16, A-H.17, A-H.18, A-H.19, A- H.20, A-H.21, A-H.22, A-H.23, A-H.24, A-H.25, A-H.26, A-H.27, A-H.28, A-H.29, A-H.30, A-H.31, A- H.32, A-H.33, A-H.34, A-H.35, A-H.36, A-H.37, A-H.38, A-H.39, A-H.40, A-H. l, A-H.42, A-H.43, A- H.44, A-H.45, A-H.46, A-H.47, A-H.48, A-H.49, A-H.50, A-H.51, A-H.52, A-H.53, A-H.54, A-H.55, A- H.56, A-H.57, A-H.58, A-H.59, A-H.60, A-H.61, A-H.62, A-H.63, A-H.64, A-H.65, A-H.66, A-H.67, A- H.68, A-H.69, A-H.70, A-H.71, A-H.72, A-H.73, A-H.74, A-H.75, A-H.76, A-H.77, A-H.78, A-H.79, A- H.80, A-H.81, A-H.82, A-H.83, A-H.84, or A-H.85, or a sequence with at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or more identity thereto.

[0511] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule comprises a VL of A-H. 1, A-H.2, A-H.3, A-H.4, A-H.5, A-H.6, A-H.7, A- H.8, A-H.9, A-H.10, A-H. l l, A-H.12, A-H.13, A-H.14, A-H.15, A-H.16, A-H.17, A-H.18, A-H.19, A-WSGR Docket No. 53676-759.601H.20, A-H.21, A-H.22, A-H.23, A-H.24, A-H.25, A-H.26, A-H.27, A-H.28, A-H.29, A-H.30, A-H.31, A- H.32, A-H.33, A-H.34, A-H.35, A-H.36, A-H.37, A-H.38, A-H.39, A-H.40, A-H.l, A-H.42, A-H.43, A- H.44, A-H.45, A-H.46, A-H.47, A-H.48, A-H.49, A-H.50, A-H.51, A-H.52, A-H.53, A-H.54, A-H.55, A- H.56, A-H.57, A-H.58, A-H.59, A-H.60, A-H.61, A-H.62, A-H.63, A-H.64, A-H.65, A-H.66, A-H.67, A- H.68, A-H.69, A-H.70, A-H.71, A-H.72, A-H.73, A-H.74, A-H.75, A-H.76, A-H.77, A-H.78, A-H.79, A- H.80, A-H.81, A-H.82, A-H.83, A-H.84, or A-H.85, or a sequence with at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or more identity thereto.

[0512] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule comprises a VH of A-H.l, A-H.2, A-H.3, A-H.4, A-H.5, A-H.6, A-H.7, A- H.8, A-H.9, A-H.10, A-H.l l, A-H.12, A-H.13, A-H.14, A-H.15, A-H.16, A-H.17, A-H.18, A-H.19, A- H.20, A-H.21, A-H.22, A-H.23, A-H.24, A-H.25, A-H.26, A-H.27, A-H.28, A-H.29, A-H.30, A-H.31, A- H.32, A-H.33, A-H.34, A-H.35, A-H.36, A-H.37, A-H.38, A-H.39, A-H.40, A-H.l, A-H.42, A-H.43, A- H.44, A-H.45, A-H.46, A-H.47, A-H.48, A-H.49, A-H.50, A-H.51, A-H.52, A-H.53, A-H.54, A-H.55, A- H.56, A-H.57, A-H.58, A-H.59, A-H.60, A-H.61, A-H.62, A-H.63, A-H.64, A-H.65, A-H.66, A-H.67, A- H.68, A-H.69, A-H.70, A-H.71, A-H.72, A-H.73, A-H.74, A-H.75, A-H.76, A-H.77, A-H.78, A-H.79, A- H.80, A-H.81, A-H.82, A-H.83, A-H.84, or A-H.85, or a sequence with at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or more identity thereto; and a VL of A-H.l, A-H.2, A-H.3, A-H.4, A-H.5, A-H.6, A-H.7, A-H.8, A-H.9, A-H.10, A-H.l l, A-H.12, A-H.13, A-H.14, A-H.15, A-H.16, A-H.17, A-H.18, A- H.19, A-H.20, A-H.21, A-H.22, A-H.23, A-H.24, A-H.25, A-H.26, A-H.27, A-H.28, A-H.29, A-H.30, A- H.31, A-H.32, A-H.33, A-H.34, A-H.35, A-H.36, A-H.37, A-H.38, A-H.39, A-H.40, A-H.l, A-H.42, A- H.43, A-H.44, A-H.45, A-H.46, A-H.47, A-H.48, A-H.49, A-H.50, A-H.51, A-H.52, A-H.53, A-H.54, A- H.55, A-H.56, A-H.57, A-H.58, A-H.59, A-H.60, A-H.61, A-H.62, A-H.63, A-H.64, A-H.65, A-H.66, A- H.67, A-H.68, A-H.69, A-H.70, A-H.71, A-H.72, A-H.73, A-H.74, A-H.75, A-H.76, A-H.77, A-H.78, A- H.79, A-H.80, A-H.81, A-H.82, A-H.83, A-H.84, or A-H.85, or a sequence with at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or more identity thereto.

[0513] Exemplary anti-TCRpV antibody molecules and the corresponding TCRpV subfamilies recognized by said anti-TCRpV antibody molecules are disclosed in Table 10.

[0514] The various TCRpV subfamilies and / or subfamily members can be expressed at different levels in individuals, e.g., healthy individuals, as disclosed in Kitaura K. et al (2016), BMC Immunology vol 17: 38, the entire contents of which are hereby incorporated by reference. For example, TCRp V6-5 is represented in approximately 3-6% healthy donors.

[0515] The representation of various TCRBV subfamilies and / or subfamily members can also be different in cancer cells. For example, TCRpV is present in about 3-6% of tumor infdtrating T cells irrespective of tumor type (see Li B. et al., Nature Genetics, 2016, vol:48(7):725-32 the entire contents of which are hereby incorporated by references). Li et al., also disclose that TCRp V6-5 is present at a high frequency in tumor cells.WSGR Docket No. 53676-759.601Anti-TCRB V6 antibodies

[0516] In one aspect, provided herein is an anti-TCRpV antibody molecule that binds to human TCRp V6, e.g., a TCRp V6 subfamily comprising: TCRp V6-4*01, TCRp V6-4*02, TCRp V6-9*01, TCRp V6-8*0I, TCRP V6-5*0I, TCRp V6-6*02, TCRp V6-6*01, TCRp V6-2*01, TCRp V6-3*01 or TCRp V6-l*01. In some embodiments the TCRP V6 subfamily comprises TCRP V6-5*01 or a variant thereof. In some embodiments, TCRp V6 comprises TCRp V6-4*01, or a variant thereof. In some embodiments, TCRP V6 comprises TCRP V6-4*02, or a variant thereof. In some embodiments, TCRP V6 comprises TCRp V6-9*01, or a variant thereof. In some embodiments, TCRp V6 comprises TCRp V6-8*01, or a variant thereof. In some embodiments, TCRp V6 comprises TCRp V6-5*01, or a variant thereof. In some embodiments, TCRP V6 comprises TCRP V6-6*02, or a variant thereof. In some embodiments, TCRP V6 comprises TCRp V6-6*01, or a variant thereof. In some embodiments, TCRp V6 comprises TCRp V6-2*01, or a variant thereof. In some embodiments, TCRp V6 comprises TCRp V6-3*01, or a variant thereof. In some embodiments, TCRp V6 comprises TCRp V6-l*01, or a variant thereof.

[0517] In some embodiments, TCRp V6-5*01 is encoded by the nucleic acid sequence of SEQ ID NO: 43, or a sequence having 85%, 90%, 95%, 99% or more identity thereof. In some embodiments, TCRP V6-5*01 comprises the amino acid sequence of SEQ ID NO: 44, or an amino acid sequence having 85%, 90%, 95%, 99% or more identity thereof.

[0518] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, is a non-murine antibody molecule, e.g., a human or humanized antibody molecule. In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti- TCRp V6-5*01) antibody molecule is a human antibody molecule. In some embodiments, the anti- TCRpV antibody molecule, e.g., anti-TCRp V 6 (e.g., anti-TCRp V6-5*01) antibody molecule is a humanized antibody molecule.

[0519] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, is isolated or recombinant.

[0520] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises at least one antigen-binding region, e.g., a variable region or an antigen-binding fragment thereof, from an antibody described herein, e.g., an antibody chosen from any one of A-H.l to A-H.85, e.g., A-H. 1, A-H.2 or A-H.68, or an antibody described in Table 1, or encoded by a nucleotide sequence in Table 1, or a sequence substantially identical (e.g., at least 80%, 85%, 90%, 92%, 95%, 97%, 98%, 99% or higher identical) to any of the aforesaid sequences.

[0521] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises at least one, two, three or four variable regions from an antibody described herein, e.g, an antibody chosen from any one of A-H.l to A-H.85, e.g., A-H.l, A-H.2 or A- H.68, or an antibody described in Table 1, or encoded by a nucleotide sequence in Table 1, or a sequence substantially identical (e.g., at least 80%, 85%, 90%, 92%, 95%, 97%, 98%, 99% or higher identical) to any of the aforesaid sequences.WSGR Docket No. 53676-759.601

[0522] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises at least one or two heavy chain variable regions from an antibody described herein, e.g., an antibody chosen from any one of A-H. 1 to A-H.85, e.g., A-H.l, A-H.2 or A-H.68, or an antibody molecule described in Table 1, or encoded by a nucleotide sequence in Table 1, or a sequence substantially identical (e.g., at least 80%, 85%, 90%, 92%, 95%, 97%, 98%, 99% or higher identical) to any of the aforesaid sequences.

[0523] In some embodiments, the anti-TCRpV antibody molecule comprises a heavy chain variable region (VH) having a consensus sequence of SEQ ID NO: 231 or 3290.

[0524] SEQ ID NO: 231 - Consensus VHQVQLVQSGAEVKKPGSSVKVSCKASGH / T / G / YD / T / SFH / R / D / K / TL / D / K / T / NW / F / T / I / Y / GYIHWV RQAPGQGLEWMGR / WV / I / FF / S / YA / PGSGN / ST / V / Y / IK / RYNEKFKGRVTITADTSTSTAYMELSS LRSEDTAVYYCAG / VSY / IYSY / AD / GVLDYWGQGTTVTVSS

[0525] SEQ ID NO: 3290 - Consensus VHQVQLVQSGAEVKKPGSSVKVSCKASGXIX2FX3X4X5YIHWVRQAPGQGLEWMGX6X7X8X9GSGX 10X11X12YNEKFKGRVTITADTSTSTAYMELSSLRSEDTAVYYCAX13SX14YSX15X16VLDYWGQGT TVTVSS, where-in: XI is H or T or G or Y; X2 is D or T or S; X3 is H or R or D or K or T; X4 is L or D or K or T or N; X5 is W or F or T or I or Y or G; X6 is R or W; X7 is V or I or F; X8 is F or S or Y; X9 is A or P; X10 is N or S; XI 1 is T or V or Y or I; X12 is K or R; X13 is G or V; X14 is Y or I; X15 is Y or A; and X16 is D or G.

[0526] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises at least one or two light chain variable regions from an antibody described herein, e.g, an antibody chosen from any one of A-H.l to A-H.85, e.g., A-H.l, A-H.2 or A- H.68, or an antibody described in Table 1, or encoded by a nucleotide sequence in Table 1, or a sequence substantially identical (e.g., at least 80%, 85%, 90%, 92%, 95%, 97%, 98%, 99% or higher identical) to any of the aforesaid sequences.

[0527] In some embodiments, the anti-TCRpV antibody molecule comprises a light chain variable region (VL) having a consensus sequence of SEQ ID NO: 230 or 3289.

[0528] SEQ ID NO: 230 - Consensus VLDIQMTQSPSFLSASVGDRVTITCKASQNVG / E / A / DN / DR / KVAWY / HQQKPGKAPKALIYSSSHRY K / SGVPSRFSGSGSGTEFTLTISSLQPEDFATYFCQQFKSYPLTFGQGTKLEIK

[0529] SEQ ID NO: 3289 - Consensus VL DIQMTQSPSFLSASVGDRVTITCKASQNVX1X2X3VAWX4QQKPGKAPKALIYSSSHRYX5GVPSRF SGSGSGTEFTLTISSLQPEDFATYFCQQFKSYPLTFGQGTKLEIK, wherein XI is G, E, A or D; X2 is N or D; X3 is R or K; X4 is Y or H; and X5 is K or S

[0530] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, comprises a heavy chain constant region for an IgG4, e.g., a human IgG4. In still another embodiment, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule includes a heavy chain constant region for an IgGl, e.g., a human IgGl. InWSGR Docket No. 53676-759.601 some embodiments, the heavy chain constant region comprises an amino sequence set forth in Table 3, 21, or 22, or a sequence substantially identical (e.g., at least 80%, 85%, 90%, 92%, 95%, 97%, 98%, 99% or higher identical) thereto.

[0531] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, includes a kappa light chain constant region, e.g., a human kappa light chain constant region. In some embodiments, the light chain constant region comprises an amino sequence set forth in Table 3, 21, or 22, or a sequence substantially identical (e.g., at least 80%, 85%, 90%, 92%, 95%, 97%, 98%, 99% or higher identical) thereto.

[0532] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, includes at least one, two, or three complementarity determining regions (CDRs) from a heavy chain variable region (VH) of an antibody described herein, e.g., an antibody chosen from any one of A-H.l to A-H.85, e.g., A-H.l, A-H.2 or A-H.68, or an antibody described in Table 1, or encoded by a nucleotide sequence in Table 1, or a sequence substantially identical (e.g., at least 80%, 85%, 90%, 92%, 95%, 97%, 98%, 99% or higher identical) to any of the aforesaid sequences.

[0533] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, includes at least one, two, or three CDRs (or collectively all of the CDRs) from a heavy chain variable region comprising an amino acid sequence shown in Table 1, or encoded by a nucleotide sequence shown in Table 1. In some embodiments, one or more of the CDRs (or collectively all of the CDRs) have one, two, three, four, five, six or more changes, e.g., amino acid substitutions or deletions, relative to the amino acid sequence shown in Table 1, or encoded by a nucleotide sequence shown in Table 1.

[0534] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, includes at least one, two, or three complementarity determining regions (CDRs) from a light chain variable region of an antibody described herein, e.g., an antibody chosen from any one of A-H.l to A-H.85, e.g., A-H.l, A-H.2 or A-H.68, or an antibody described in Table 1, or encoded by a nucleotide sequence in Table 1, or a sequence substantially identical (e.g, at least 80%, 85%, 90%, 92%, 95%, 97%, 98%, 99% or higher identical) to any of the aforesaid sequences.

[0535] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, includes at least one, two, or three CDRs (or collectively all of the CDRs) from a light chain variable region comprising an amino acid sequence shown in Table 1, or encoded by a nucleotide sequence shown in Table 1. In some embodiments, one or more of the CDRs (or collectively all of the CDRs) have one, two, three, four, five, six or more changes, e.g., amino acid substitutions or deletions, relative to the amino acid sequence shown in Table 1, or encoded by a nucleotide sequence shown in Table 1.

[0536] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, includes at least one, two, three, four, five or six CDRs (or collectively all of the CDRs) from a heavy and light chain variable region comprising an amino acid sequence shown in Table 1, or encoded by a nucleotide sequence shown in Table 1. In some embodiments, one or more ofWSGR Docket No. 53676-759.601 the CDRs (or collectively all of the CDRs) have one, two, three, four, five, six or more changes, e.g., amino acid substitutions or deletions, relative to the amino acid sequence shown in Table 1, or encoded by a nucleotide sequence shown in Table 1.

[0537] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, molecule includes all six CDRs from an antibody described herein, e.g., an antibody chosen from any one of A-H.1 to A-H.85, e.g., A-H. 1, A-H.2 or A-H.68, or an antibody described in Table 1, or encoded by a nucleotide sequence in Table 1, or closely related CDRs, e.g, CDRs which are identical or which have at least one amino acid alteration, but not more than two, three or four alterations (e.g., substitutions, deletions, or insertions, e.g., conservative substitutions). In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, may include any CDR described herein.

[0538] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule includes at least one, two, or three CDRs according to Kabat et al. (e.g., at least one, two, or three CDRs according to the Kabat definition as set out in Table 1) from a heavy chain variable region of an antibody described herein, e.g. , an antibody chosen from any one of A-H. 1 to A- H.85, e.g., A-H.l, A-H.2 or A-H.68, or an antibody described in Table 1, or a sequence substantially identical (e.g, at least 80%, 85%, 90%, 92%, 95%, 97%, 98%, 99% or higher identical) to any of the aforesaid sequences; or which have at least one amino acid alteration, but not more than two, three or four alterations (e.g, substitutions, deletions, or insertions, e.g., conservative substitutions) relative to one, two, or three CDRs according to Kabat et al. shown in Table 1.

[0539] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule includes at least one, two, or three CDRs according to Kabat et al. (e.g., at least one, two, or three CDRs according to the Kabat definition as set out in Table 1) from a light chain variable region of an antibody described herein, e.g. , an antibody chosen from any one of A-H. 1 to A- H.85, e.g., A-H.l, A-H.2 or A-H.68, or an antibody described in Table 1, or a sequence substantially identical (e.g, at least 80%, 85%, 90%, 92%, 95%, 97%, 98%, 99% or higher identical) to any of the aforesaid sequences; or which have at least one amino acid alteration, but not more than two, three or four alterations (e.g, substitutions, deletions, or insertions, e.g., conservative substitutions) relative to one, two, or three CDRs according to Kabat et al. shown in Table 1.

[0540] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, includes at least one, two, three, four, five, or six CDRs according to Kabat et al. (e.g., at least one, two, three, four, five, or six CDRs according to the Kabat definition as set out in Table 1) from the heavy and light chain variable regions of an antibody described herein, e.g., an antibody chosen from any one of A-H.1 to A-H.85, e.g., A-H. 1, A-H.2 or A-H.68, or an antibody described in Table 1, or encoded by a nucleotide sequence in Table 1; or a sequence substantially identical (e.g, at least 80%, 85%, 90%, 92%, 95%, 97%, 98%, 99% or higher identical) to any of the aforesaid sequences; or which have at least one amino acid alteration, but not more than two, three orWSGR Docket No. 53676-759.601 four alterations (e.g, substitutions, deletions, or insertions, e.g., conservative substitutions) relative to one, two, three, four, five, or six CDRs according to Kabat et al. shown in Table 1.

[0541] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, includes all six CDRs according to Kabat et al. (e.g., all six CDRs according to the Kabat definition as set out in Table 1) from the heavy and light chain variable regions of an antibody described herein, e.g., an antibody chosen from any one of A-H.l to A-H.85, e.g., A-H.l, A- H.2 or A-H.68, or an antibody described in Table 1, or encoded by a nucleotide sequence in Table 1; or a sequence substantially identical (e.g., at least 80%, 85%, 90%, 92%, 95%, 97%, 98%, 99% or higher identical) to any of the aforesaid sequences; or which have at least one amino acid alteration, but not more than two, three or four alterations (e.g., substitutions, deletions, or insertions, e.g., conservative substitutions) relative to all six CDRs according to Kabat et al. shown in Table 1. In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, may include any CDR described herein.

[0542] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule, includes at least one, two, or three hypervariable loops that have the same canonical structures as the corresponding hypervariable loop of an antibody described herein, e.g., an antibody chosen from chosen from any one of A-H.l to A-H.85, e.g., A-H.l, A-H.2 or A-H.68, e.g., the same canonical structures as at least loop 1 and / or loop 2 of the heavy and / or light chain variable domains of an antibody described herein. See, e.g, Chothia et al., (1992) J. Mol. Biol. 227:799-817; Tomlinson et al., (1992) J. Mol. Biol. 227:776-798 for descriptions of hypervariable loop canonical structures. These structures can be determined by inspection of the tables described in these references.

[0543] In some embodiments, the anti-TCRpV antibody molecule, e.g., anti-TCRp V6 (e.g., anti-TCRp V6-5*01) antibody molecule includes at least one, two, or three CDRs according to Chothia et al. (e.g., at least one, two, or three CDRs according to the Chothia definition as set out in Table 1) from a heavy chain variable region of an antibody described herein, e.g., an antibody chosen from any one of A-H. 1 to A-H.85, e.g., A-H.l, A-H.2 or A-H.68, or as describ...

Claims

1. WSGR Docket No. 53676-759.601CLAIMSWHAT IS CLAIMED IS:

1. A composition comprising an IL-21 mutein polypeptide comprising a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, wherein the IL-21 mutein polypeptide comprises an aromatic amino acid substitution of He at position 8 of SEQ ID NO: 2193.

2. A composition comprising an IL-21 mutein polypeptide, wherein when a polynucleotide comprising a sequence encoding the IL-21 mutein polypeptide is expressed in a cell:(a) the ratio of the amount of a full-length IL-21 mutein polypeptide produced to the amount of a less than full-length IL-21 mutein polypeptide produced is higher than the ratio of the amount of a corresponding full length IL-21 wild-type polypeptide produced to the amount of a less than full-length IL-21 wild-type polypeptide produced when a polynucleotide comprising a sequence encoding a IL-21 wild-type polypeptide is expressed in a cell; and / or(b) the amount of the full-length IL-21 mutein polypeptide produced is higher than the amount of the corresponding full-length IL-21 wild-type polypeptide produced when the polynucleotide comprising a sequence encoding the IL-21 wild-type polypeptide is expressed in a cell.

3. A composition comprising an IL-21 mutein polypeptide, wherein the IL-21 mutein polypeptide is less susceptible to proteolytic cleavage when expressed in a cell compared to a corresponding IL-21 wild-type polypeptide when expressed in a cell.

4. The composition of claim 2 or 3, wherein the IL-21 wild-type polypeptide comprises the sequence of SEQ ID NO: 2193.

5. The composition of any one of claims 2-4, wherein the IL-21 mutein polypeptide comprises an aromatic amino acid substitution of He at position 8 of SEQ ID NO: 2193.

6. The composition of any one of claims 1-5, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe or Trp.

7. The composition of any one of claims 1-6, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe.

8. The composition of any one of claims 1-6, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp.

9. The composition of any one of claims 1-8, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, or any combination thereof.

10. The composition of any one of claims 1-9, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu.

11. The composition of any one of claims 1-10, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Lys.WSGR Docket No. 53676-759.60112. The composition of any one of claims 1-11, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu.

13. The composition of any one of claims 1-7 and 9-12, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe, an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Lys, an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu.

14. The composition of any one of claims 1-13, wherein the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5033.

15. The composition of any one of claims 1-14, wherein the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5033.

16. The composition of any one of claims 1-15, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193 with Thr, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193 with Gly, an amino acid substitution ofHis at position 120 of SEQ ID NO: 2193 with Asp, an amino acid substitution of Leu at position 123 of SEQ ID NO: 2193 with Thr, or any combination thereof.

17. The composition of any one of claims 1, 6, 8, and 16, wherein the IL-21 mutein polypeptide comprise an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, and an amino acid substitution ofHis at position 120 of SEQ ID NO: 2193 with Asp.

18. The composition of any one of claims 1, 6, 8, 16, and 17, wherein the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5025.

19. The composition of any one of claims 1, 6, 8, and 16-18, wherein the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5025.

20. The composition of any one of claims 1-7, and 11, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe, and an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Lys.

21. The composition of any one of claims 1-7, 11, and 20, wherein the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5026.

22. The composition of any one of claims 1-7, 11, 20, and 21, wherein the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5026.

23. The composition of any one of claims 1, 6, 8, and 16, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193 with Thr, and an amino acid substitution ofHis at position 120 of SEQ ID NO: 2193 with Asp.

24. The composition of any one of claims 1, 6, 8, 16, and 23, wherein the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5027.WSGR Docket No. 53676-759.60125. The composition of any one of claims 1, 6, 8, 16, 23, and 24, wherein the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5027.

26. The composition of any one of claims 1, 6, 8-10, and 16, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193 with Gly, and an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp.

27. The composition of any one of claims 1, 6, 8-10, 16, and 26, wherein the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5029.

28. The composition of any one of claims 1, 6, 8-10, 16, 26, and 27, wherein the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5029.

29. The composition of any one of claims 1-7 and 9-11, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe, an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Lys, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu.

30. The composition of any one of claims 1-7, 9-11, and 29, wherein the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5030.

31. The composition of any one of claims 1-7, 9-11, 29, and 30, wherein the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5030.

32. The composition of any one of claims 1, 6, 8-10, and 16, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193 with Thr, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193 with Gly, an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp, and an amino acid substitution of Leu at position 123 of SEQ ID NO: 2193 with Thr.

33. The composition of any one of claims 1, 6, 8-10, 16, and 32, wherein the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5031.

34. The composition of any one of claims 1, 6, 8-10, 16, 32, and 33, wherein the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5031 .

35. The composition of any one of claims 1, 6, 8-10, 12, and 16, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution ofWSGR Docket No. 53676-759.601Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp.

36. The composition of any one of claims 1, 6, 8-10, 12, 16, and 35, wherein the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5032.

37. The composition of any one of claims 1, 6, 8-10, 12, 16, 35, and 36, wherein the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5032.

38. The composition of any one of claims 1, 6, 8-10, 12, and 16, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193 with Thr, an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193 with Gly, an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp, and an amino acid substitution of Leu at position 123 of SEQ ID NO: 2193 with Thr.

39. The composition of any one of claims 1, 6, 8-10, 12, 16, and 38, wherein the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5034.

40. The composition of any one of claims 1, 6, 8-10, 12, 16, 38, and 39, wherein the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5034.

41. A multispecific molecule comprising:(i) a first domain that binds to one or more subunits of a T cell receptor complex; and(ii) a second domain comprising the IL-21 mutein polypeptide of the composition of any one of claims 1-40.

42. A multispecific molecule comprising:(i) a first domain that binds to one or more subunits of a T cell receptor complex; and(ii) a second domain comprising a IL-21 mutein polypeptide, wherein the IL-21 mutein polypeptide comprises a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, or any combination thereof.

43. The multispecific molecule of claim 42, wherein the IL-21 mutein polypeptide comprises a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of ArgWSGR Docket No. 53676-759.601 at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu.

44. The multispecific molecule of claim 42 or 43, wherein the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5028.

45. The multispecific molecule of any one of claims 42-44, wherein the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5028.

46. A multispecific molecule comprising:(i) a first domain that binds to one or more subunits of a T cell receptor complex; and(ii) a second domain comprising a IL-21 mutein polypeptide, wherein the IL-21 mutein polypeptide comprises a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, and the IL-21 mutein polypeptide comprises an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, or any combination thereof.

47. The multispecific molecule of claim 46, wherein the IL-21 mutein polypeptide comprises a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, and the IL-21 mutein polypeptide comprises an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu.

48. The multispecific molecule of claim 46 or 47, wherein the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5035.

49. The multispecific molecule of any one of claims 46-48, wherein the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5035.

50. A multispecific molecule comprising:(i) a first domain that binds to one or more subunits of a T cell receptor complex; and(ii) a second domain comprising a fusion polypeptide comprising a IL-21 polypeptide sequence or a fragment thereof fused to an IL-4 sequence or a fragment thereof.

51. Hie multispecific molecule of claim 50, wherein the fusion polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5052 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5053 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5054.

52. The multispecific molecule of claim 50 or 51, wherein the fusion polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5036.

53. The multispecific molecule of any one of claims 50-52, wherein the fusion polypeptide comprises the sequence of SEQ ID NO: 5052 operatively linked to the sequence of SEQ ID NO: 5053 operatively linked to the sequence of SEQ ID NO: 5054.WSGR Docket No. 53676-759.60154. The multispecific molecule of any one of claims 50-53, wherein the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5036.

55. The multispecific molecule of any one of claims 41-54, wherein when the first domain binds to the one or m ore subunits of a T cell receptor complex, the first domain activates the one or more subunits of a T cell receptor complex.

56. The multispecific molecule of claim 41-55, wherein the one or more subunits of a T cell receptor complex express on a T ceil in a T cell population.

57. A multispecific molecule comprising:(i) a first domain that binds to a receptor on a T cell in a T cell population; and(ii) a second domain comprising the IL-21 mutein polypeptide of the composition of any one of claims 1-40, wherein the receptor on a T cell in a T cell population is not CD 8.

58. A multispecific molecule comprising:(i) a first domain that binds to a receptor on a T cell in a T cell population; and(ii) a second domain comprising a IL-21 mutein polypeptide, wherein the IL-21 mutein polypeptide comprises a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, and the IL-21 mutein polypeptide comprises an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, or any combination thereof, wherein the receptor on a T cell in a T cell population is not CD 8.

59. Hie multispecific molecule of claim 58, wherein the IL-21 mutein polypeptide comprises a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, and the IL-21 mutein polypeptide comprises an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu,60. The multispecific molecule of claim 58 or 59, wherein the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5028.

61. The multispecific molecule of any one of claims 58-60, wherein the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5028.

62. A multispecific molecule comprising:(i) a first domain that binds to a receptor on a T cell in a T cell population; and(ii) a second domain comprising a IL-21 mutein polypeptide, wherein the IL-21 mutein polypeptide comprises a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, and the IL-21 mutein polypeptide comprises an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 withWSGR Docket No. 53676-759.601Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, or any combination thereof, wherein the receptor on a T cell in a T cell population is not CD 8.

63. The multispecific molecule of claim 62, wherein the IL-21 mutein polypeptide comprises a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, and the IL-21 mutein polypeptide comprises an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu.

64. The multispecific molecule of claim 62 or 63, wherein the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5035.

65. The multispecific molecule of any one of claims 62-64, wherein the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5035.

66. A multispecific molecule comprising:(i) a first domain that binds to a receptor on a T cell in a T cell population; and(ii) a second domain comprising a fusion polypeptide comprising a IL-21 polypeptide sequence or a fragment thereof fused to an IL-4 sequence or a fragment thereof, wherein the receptor on a T cell in a T cell population is not CD 8.

67. The multispecific molecule of claim 66, wherein the fusion polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5052 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5053 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5054.

68. Hie multispecific molecule of claim 66 or 67, wherein the fusion polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5036.

69. The multispecific molecule of any one of claims 66-68, wherein the fusion polypeptide comprises the sequence of SEQ ID NO: 5052 operatively linked to the sequence of SEQ ID NO: 5053 operatively linked to the sequence of SEQ ID NO: 5054.

70. The multispecific molecule of any one of claims 66-69, wherein the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5036.71 . Hie multispecific molecule of any one of claims 57-70, wherein when the first domain binds to the receptor on a T cell in a T cell population, the first domain activates the receptor on a T cell in a T cell population.

72. Hie multispecific molecule of any one of claims 41-71, wherein the first domain binds to a T cell receptor alpha (TCRa) chain, a T cell receptor beta (TCRp) chain, a T cell receptor gamma (TCRy) chain, a T cell receptor delta (TCR8) chain, a CD3 gamma (CD3y) chain, a CD3 delta (CD35) chain, a CD3 epsilon (CD3s) chain, a CD3 zeta (CD3Q chain, or any combination thereof.

73. The multispecific molecule of any one of claims 41-72, wherein the first domain binds to a T cell receptor beta (TCR ) chain.WSGR Docket No. 53676-759.60174. The multispecific molecule of any one of claims 41 -73, wherein the first domain binds to a T cell receptor beta variable (TCRpV) region.

75. The multispecific molecule of any one of claims 41-72, wherein the first domain binds to a T ceil receptor alpha (TCRa) chain.

76. The multispecific molecule of any one of claims 41-73, wherein the first domain binds to a T cell receptor alpha variable (TCRaV) region.77.rflie multispecific molecule of any one of claims 41-74, wherein the first domain binds to a TCRpV region of TCRpVl, TCRPV2, TCRpV3, TCRpV4, TCRpV5, CRPV6, TCRpV7, TCRpV8, TCRPV9, TCRPV 10, TCRpV 11, TCR Vl 2, TCRpV 19, TCRPV20, TCRPV21 , TCR V23, TCRPV24, TCRPV25, TCRPV26, TCRpV27, TCRpV28, TCRPV29, or TCR V30.

78. The multispecific molecule of any one of claims 41-74, wherein the first domain binds to a TCRpV region of TCRpV2, TCRPV4-1, TCRPV4-2, TCRpV5-l, TCRpV5-5, TCRpV5-6, TCRPV6, TCRPV6-5, TCRPV6-6, TCRPV6-9, TCRPV7-2, TCRPV7-3, TCRPV7-8, TCRPV7-9, TCRPV9. TCRPVIO-I, TCRPV10-2, TCRpV10-3, TCRpVl l-2, TCRPV12-3, TCRPV12-4, TCRPV12-5, TCRPV19, TCRPV20-1, TCRPV21, TCRPV24-1, TCRpV25-l, or TCR V28.

79. The multispecific molecule of any one of claims 41-74, wherein the first domain binds to a TCRpV region of TCRpV2, TCRPV3-1, TCRPV4-1, TCRPV4-2, TCRpV5-l, TCRpV5-4, TCRpV5-5, TCRPV5-6, TCRPV6-1, TCRPV6-5, TCRPV6-6, TCRPV7-3, TCRPV7-6, TCRPV7-8, TCR V9, TCRPV11-2, TCRPV19, TCRpV20-l, TCRpV24-l, TCRpV27, TCRPV28, TCRPV29-1, or TCRpV30.

80. The multispecific molecule of any one of claim s 41-74, wherein the first domain binds to a TCRpV region of TCRPV5, TCRPV6, TCRpVIO, TCRPV12, or TCRPV20.

81. Hie multispecific molecule of any one of claims 41-80, wherein the first domain comprises an antibody molecule or an antigen binding domain.

82. The multispecific molecule of claim 81, wherein the antibody molecule or the antigen binding domain comprises a scFv, a full-length antibody, a Fab, a F(ab')2, an Fv, a single chain Fv, a camelid antibody, a half arm antibody, a diabody, a bivalent antibody, a monovalent antibody, or a bispecific antibody.

83. The multispecific molecule of claim 81 or 82, wherein the antibody molecule or the antigen binding domain comprises a scFv, a single domain antibody, a camelid antibody, or a Fab.

84. The multispecific molecule of any one of claims 81 -83, wherein the antibody molecule or the antigen binding domain comprises a Fab.

85. The multispecific molecule of any one of claims 81 -84, wherein the antibody molecule or the antigen binding domain comprises a heavy chain variable region (VH) comprising a heavy chain complementarity determining region 1 (HC CDR1) sequence comprising any one of the HC CDR1 sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25, a heavy chain complementarity determining region 2 (HC CDR2) sequence comprising any one of the HC CDR2 sequences listed in Tablesl, 2, 10, 12, 13, 21, 22, 23, 24, or 25, and a heavy chain complementarity determiningWSGR Docket No. 53676-759.601 region 3 (HC CDR3) sequence of comprising any one of the HC CDR3 sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25.

86. The multispecific molecule of any one of claims 81-85, wherein the antibody molecule or the antigen binding domain comprises a light chain variable region (VL) comprising a light chain complementarity determining region 1 (LC CDR1) sequence comprising any one of the LC CDR1 sequences listed in Tablesl, 2, 10, 12, 13, 21, 22, 23, 24, or 25, a light chain complementarity determining region 2 (LC CDR2) sequence comprising any one of the LC CDR2 sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25, and a light chain complementarity determining region 3 (LC CDR3) sequence of comprising any one of the LC CDR3 sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25.

87. The multispecific molecule of any one of claims 81-86, wherein the antibody molecule or the antigen binding domain comprises:(i) a heavy chain variable region (VH) comprising a heavy chain complementarity determining region 1 (HC CDR1) sequence comprising any one of the HC CDR1 sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25, a heavy chain complementarity determining region 2 (HC CDR2) sequence comprising any one of the HC CDR2 sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25, and a heavy chain complementarity determining region 3 (HC CDR3) sequence of comprising any one of the HC CDR3 sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25.; and(ii) a light chain variable region (VL) comprising a light chain complementarity determining region 1 (LC CDR1) sequence comprising any one of the LC CDR1 sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25, a light chain complementarity determining region 2 (LC CDR2) sequence comprising any one of the LC CDR2 sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25, and a light chain complementarity determining region 3 (LC CDR3) sequence of comprising any one of the LC CDR3 sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25.

88. The multispecific molecule of any one of claims 81-87, wherein the antibody molecule or the antigen binding domain comprises a VH comprising an amino acid sequence having at least 80% sequence identity to any one of the VH sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25.

89. The multispecific molecule of any one of claims 81 -88, wherein the antibody molecule or the antigen binding domain comprises a VL comprising an amino acid sequence having at least 80% sequence identity to any one of the VL sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25.

90. The multispecific molecule of any one of claims 81-89, wherein the antibody molecule or the antigen binding domain comprises a VH comprising an amino acid sequence having at least 80% sequence identity to any one of the VH sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25; and a VL comprising an amino acid sequence having at least 80% sequence identity to any one of the VL sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25.WSGR Docket No. 53676-759.60191. The multispecific molecule of any one of claims 81-90, wherein the antibody molecule or the antigen binding domain comprises a VH comprising any one of the VH sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25.

92. The multispecific molecule of any one of claim s 81-91, wherein the antibody molecule or the antigen binding domain comprises a VL comprising any one of the VL sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 2593. The multispecific molecule of any one of claims 81 -92, wherein the antibody molecule or the antigen binding dom ain comprises a VH comprising any one of the VH sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25; and a VL comprising any one of the VL sequences listed in Tables 1, 2, 10, 12, 13, 21, 22, 23, 24, or 25.

94. The multispecific molecule of any one of claims 81- 3, wherein the antibody molecule or the antigen binding domain comprises a VH comprising a HC CDR1 comprising the sequence GHDFRLTYIH (SEQ ID NO: 3650), a HC CDR2 comprising the sequence RVSAGSGNVKYNEKFKG (SEQ ID NO: 3651), and a HC CDR3 comprising the sequence SYYSYDVLDY (SEQ ID NO: 47).

95. The multispecific molecule of any one of claims 81 -94, wherein the antibody molecule or the antigen binding domain comprises a VL comprising a LC CDR1 comprising the sequence KASQNVADRVV (SEQ ID NO: 3655), a LC CDR2 comprising the sequence SSSHRYK (SEQ ID NO: 3653), and a LC CDR3 comprising the sequence QQFKSYPLT (SEQ ID NO: 8).

96. The multispecific molecule of any one of claims 81-95, wherein the antibody molecule or the antigen binding domain comprises:(i) a VH comprising a HC CDR1 comprising the sequence GHDFRLTYIH (SEQ ID NO: 3650), aHC CDR2 comprising the sequence RVSAGSGNVKYNEKFKG (SEQ ID NO: 3651), and a HC CDR3 comprising the sequence SYYSYDVLDY (SEQ ID NO: 5); and(ii) a VL comprising a LC CDR1 comprising the sequence KASQNVADRVV (SEQ ID NO: 3655), a LC CDR2 comprising the sequence SSSHRYK (SEQ ID NO: 3653), and a LC CDR3 comprising the sequence QQFKSYPLT (SEQ ID NO: 8).

97. The multispecific molecule of any one of claims 81-96, wherein the antibody molecule or the antigen binding domain comprises a VH comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1346.

98. The multispecific molecule of any one of claims 81 -97, wherein the antibody molecule or the antigen binding domain comprises a VL comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1349.

99. The multispecific molecule of any one of claims 81-98, wherein the antibody molecule or the antigen binding domain comprises a VH comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1346, and a VL comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1349.

100. The multispecific molecule of any one of claims 81-99, wherein the antibody molecule or the antigen binding domain comprises a VH comprising the sequence of SEQ ID NO: 1346.WSGR Docket No. 53676-759.601101. The multispecific molecule of any one of claims 81-100, wherein the antibody molecule or the antigen binding domain comprises a VL comprising the sequence of SEQ ID NO: 1349.

102. The multispecific molecule of any one of claims 81-101, wherein tire antibody molecule or the antigen binding domain comprises a VH comprising the sequence of SEQ ID NO: 1346, and a VL comprising the sequence of SEQ ID NO: 1349.

103. The multispecific molecule of any one of claims 81 -94, wherein the antibody molecule or the antigen binding domain comprises a single chain Fv (scFv) comprising an amino acid sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 140, 153, 168, 183, or 195.

104. The multispecific molecule of any one of claims 81-94 and 103, wherein the antibody molecule or the antigen binding domain comprises a scFv comprising the sequence of SEQ ID NO: 140, 153, 168, 183, or 195.

105. The multispecific molecule of any one of claims 41-104, wherein the multispecific molecule comprises a first polypeptide chain and a second polypeptide chain; wherein the first polypeptide chain and the second polypeptide chain are non-contiguous; wherein the first polypeptide chain comprises a first member of a dimerization module and the second polypeptide chain comprises a second member of the dimerization module, wherein the first polypeptide chain and the second polypeptide chain form a complex via association of the first member of the dimerization module and the second member of the dimerization module; and wherein the dimerization module comprises an immunoglobulin constant domain.

106. The multispecific molecule of claim 105, wherein the molecule comprises the first polypeptide chain, the second polypeptide chain, and a third polypeptide chain, wherein the first polypeptide chain, the second polypeptide chain, and the third polypeptide chain are non-contiguous, and wherein:(i) the first polypeptide chain comprises a first portion of the first domain, wherein the first portion is operatively linked to the first member of a dimerization module,(ii) the second polypeptide chain comprises the second domain, wherein the second domain is operatively linked to the second member of the dimerization module, and(iii) the third polypeptide chain comprises a second portion of the first domain, wherein the first portion of the first domain and the second portion of the first domain are assembled and form the first domain.

107. The multispecific molecule of claim 106, wherein the first domain comprises an antibody molecule or an antigen binding domain, and the first portion of the first domain is a VH and the second portion of the first domain is a VL.

108. The multispecific molecule of claim 106, wherein the first domain comprises an antibody molecule or an antigen binding domain, and the first portion of the first domain is a VL and the second portion of the first domain is a VH.WSGR Docket No. 53676-759.601109. The multispecific molecule of any one of claims 105-108, wherein the first member of the dimerization module is a first Fc region, and the second member of the dimerization module is a second Fc region.

110. The multispecific molecule of claim 109, wherein the first polypeptide chain comprises the first domain operatively linked to the first Fc region, and the second polypeptide chain comprises the second domain operatively linked to the second Fc region.

111. The multispecific molecule of claim 109 or 110, wherein:(i) the first Fc region comprises a mutation that decreases Fc receptor binding relative to a Fc region without the mutation;(ii) the second Fc region comprise a mutation that decreases Fc receptor binding relative to a Fc region without the mutation; or(iii) a combination thereof.

112. The multispecific molecule of claim 1 11, wherein the mutation that decreases Fc receptor binding is an N297A mutation according to EU Numbering in a heavy chain constant region.

113. The multispecific molecule of any one of claims 109-112, w herein the first Fc region and the second Fc region comprise an Fc interface with one or more of: a knob-in-a hole, an electrostatic interaction, or a strand-exchange.

114. The multispecific molecule of any one of claims 109-113, wherein the first Fc region is an engineered Fc region comprising a knob and the second Fc region is an engineered Fc region comprising a hole, or the first Fc region is an engineered Fc region comprising a hole and the second Fc region is an engineered Fc region comprising a knob.

115. Hie multispecific molecule of any one of claims 109-114, wherein:(A)(i) the first Fc region comprises:(a) Y349C mutation according to EU Numbering,(b) T366S mutation according to EU Numbering,(c) L368A mutation according to EU Numbering, and(d) Y407V mutation according to EU Numbering; and(ii) the second Fc region comprises:(a) S354C mutation according to EU Numbering, and(b) T366W mutation according to EU Numbering; or(B)(i) the first Fc region comprises:(a) S354C mutation according to EU Numbering, and(b) T366W mutation according to EU Numbering; and(ii) the second Fc region comprises:(a) Y349C mutation according to EU Numbering,(b) T366S mutation according to EU Numbering,(c) L368A mutation according to EU Numbering, and(d) Y407V mutation according to EU Numbering.WSGR Docket No. 53676-759.601116. The multispecific molecule of any one of claims 109-115, wherein the first Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5044 or the sequence of SEQ ID NO: 5045, and the second Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5046 or the sequence of SEQ ID NO: 5047.

117. The multispecific molecule of any one of claims 109-116, wherein:(i) the first Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5044, and the second Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5046;(ii) the first Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5045, and the second Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5047;(iii) the first Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5044, and the second Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5047; or(iv) the first Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5045, and the second Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5046.

118. The multispecific molecule of any one of claims 109-117, wherein the first Fc region comprises the sequence of SEQ ID NO: 5044 or the sequence of SEQ ID NO: 5045, and the second Fc region comprises the sequence of SEQ ID NO: 5046 or the sequence of SEQ ID NO: 5047.

119. The multispecific molecule of any one of claims 109-118, wherein:(i) the first Fc region comprises the sequence of SEQ ID NO: 5044, and the second Fc region comprises the sequence of SEQ ID NO: 5046;(ii) the first Fc region comprises the sequence of SEQ ID NO: 5045, and the second Fc region comprises the sequence of SEQ ID NO: 5047;(iii) the first Fc region comprises the sequence of SEQ ID NO: 5044, and the second Fc region comprises the sequence of SEQ ID NO: 5047;(iv) the first Fc region comprises the sequence of SEQ ID NO: 5045, and the second Fc region comprises the sequence of SEQ ID NO: 5046.

120. The multispecific molecule of any one of claims 109-1 15, wherein the first Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5048 or the sequence of SEQ ID NO: 5049, and the second Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5050 or the sequence of SEQ ID NO: 5051.

121. The multispecific molecule of any one of claims 109-115 and 120, wherein:(i) the first Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5048, and the second Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5050;WSGR Docket No. 53676-759.601(ii) the first Fc region comprises a sequence having at least 80 % sequence identity to the sequence of or the sequence of SEQ ID NO: 5049, and the second Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5051;(iii) the first Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5048, and the second Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5051; or(iv) the first Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5049, and the second Fc region comprises a sequence having at least 80 % sequence identity to the sequence of SEQ ID NO: 5050.

122. The multispecific molecule of any one of claims 109-115, 120, and 121, wherein the first Fc region comprises the sequence of SEQ ID NO: 5048 or the sequence of SEQ ID NO: 5049, and the second Fc region comprises the sequence of SEQ ID NO: 5050 or the sequence of SEQ ID NO: 5051.

123. The multispecific molecule of any one of claims 109-116, and 120-122, wherein:(i) the first Fc region comprises the sequence of SEQ ID NO: 5048, and the second Fc region comprises the sequence of SEQ ID NO: 5050;(ii) the first Fc region comprises the sequence of SEQ ID NO: 5049, and the second Fc region comprises the sequence of SEQ ID NO: 5051(iii) the first Fc region comprises the sequence of SEQ ID NO: 5048, and the second Fc region comprises the sequence of SEQ ID NO: 5051; or(iv) the first Fc region comprises the sequence of SEQ ID NO: 5049, and the second Fc region comprises the sequence of SEQ ID NO: 5050.

124. The multispecific molecule of any one of claims 81-123, wherein the multispecific molecule comprises a VL operatively linked to a light chain constant region or a fragment thereof.

125. The multispecific molecule of claim 124, wherein the light chain constant region or a fragment thereof comprises a kappa light chain constant region or a fragment thereof, or a lambda light chain constant region.

126. The multispecific molecule of claim 124 or 125, wherein the light chain constant region or a fragment thereof comprise a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 39 or SEQ ID NO: 3644.

127. Hie multispecific molecule of any one of claims 124-126, wherein the light chain constant region or a fragment thereof comprise the sequence of SEQ ID NO: 39 or SEQ ID NO: 3644.

128. The multispecific molecule of any one of claims 41-74 and 77-127, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising a VH of the first domain, wherein the first domain comprises an antibody molecule or an antigen binding domain that binds to a TCRpV region, and wherein the VH is operatively linked to a first Fc region;WSGR Docket No. 53676-759.601(ii) a second polypeptide chain comprising the second domain comprising the IL-21 mutein polypeptide, wherein the IL-21 mutein polypeptide comprises a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, and the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe, an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Lys, an amino acid substitution ofLys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu; and wherein the second domain is operatively linked to a second Fc region; and(iii) a third polypeptide chain comprising a VL of the first domain, wherein the VL is operatively linked to a light chain constant region; wherein the VH of the first domain and the VL of the first domain are assembled and form the first domain.

129. The multispecific molecule of claim 128, wherein the second domain is operatively linked to the second Fc region via a linker sequence.

130. The multispecific molecule of any one of claims 41-74 and 77-129, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1346 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5044;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5033 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5046; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1349 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 3644.

131. The multispecific molecule of claim 130, wherein the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5033 is operatively linked to the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5046 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

132. The multispecific molecule of any one of claims 41-74 and 77-131, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 1346 operatively linked to the sequence of SEQ ID NO: 5044;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5033 operatively linked to the sequence of SEQ ID NO: 5046; andWSGR Docket No. 53676-759.601(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 1349 operatively linked to the sequence of SEQ ID NO: 3644.

133. The multispecific molecule of claim 132, wherein the sequence of SEQ ID NO: 5033 is operatively linked to the sequence of SEQ ID NO: 5046 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

134. The multispecific molecule of claim 42, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5055;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5060; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5059.

135. The multispecific molecule of claim 134, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 5055;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5060; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 5059.

136. The multispecific molecule of any one of claims 41-74 and 77-129, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1346 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5048;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5033 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5050; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1349 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 3644.

137. The multispecific molecule of claim 136, wherein the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5033 is operatively linked to the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5050 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

138. The multispecific molecule of any one of claims 41-74, 77-129, 136, and 137, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 1346 operatively linked to the sequence of SEQ ID NO: 5048;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5033 operatively linked to the sequence of SEQ ID NO: 5050; andWSGR Docket No. 53676-759.601(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 1349 operatively linked to the sequence of SEQ ID NO: 3644.

139. The multispecific molecule of claim 138, wherein the sequence of SEQ ID NO: 5033 is operatively linked to the sequence of SEQ ID NO: 5050 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

140. The multispecific molecule of claim 42, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5057;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5062; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5059.

141. The multispecific molecule of claim 140, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 5057;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5062; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 5059.

142. The multispecific molecule of any one of claims 41-74 and 77-127, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising a VH of the first domain, wherein the first domain comprises an antibody molecule or an antigen binding domain that binds to a TCRpV region, and wherein the VH is operatively linked to a first Fc region;(ii) a second polypeptide chain comprising the second domain comprising the IL-21 mutein polypeptide, wherein the IL-21 mutein polypeptide comprises a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, and the IL-21 mutein polypeptide comprises an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu; and wherein the second domain is operatively linked to a second Fc region; and(iii) a third polypeptide chain comprising a VL of the first domain, wherein the VL is operatively linked to a light chain constant region; wherein the VH of the first domain and the VL of the first domain are assembled and form the first domain.

143. The multispecific molecule of claim 142, wherein the second domain is operatively linked to the second Fc region via a linker sequence.

144. The multispecific molecule of any one of claims 41-74, 77-127, 142, and 143, wherein the multispecific molecule comprises:WSGR Docket No. 53676-759.601(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1346 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5044;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5028 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5046; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1349 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 3644.

145. The multispecific molecule of claim 144, wherein the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5028 is operatively linked to the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5046 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

146. The multispecific molecule of any one of claims 41-74, 77-127, and 142-145, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 1346 operatively linked to the sequence of SEQ ID NO: 5044;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5028 operatively linked to the sequence of SEQ ID NO: 5046; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 1349 operatively linked to the sequence of SEQ ID NO: 3644.

147. The multispecific molecule of claim 146, wherein the sequence of SEQ ID NO: 5028 is operatively linked to the sequence of SEQ ID NO: 5046 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

148. The multispecific molecule of claim 42, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5055;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5064; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5059.

149. The multispecific molecule of claim 148, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 5055;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5064; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 5059.

150. The multispecific molecule of any one of claims 41-74, 77-127, 142, and 143, wherein the multispecific molecule comprises:WSGR Docket No. 53676-759.601(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1346 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5048;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5028 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5050; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1349 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 3644.

151. The multispecific molecule of claim 150, wherein the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5028 is operatively linked to the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5050 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

152. The multispecific molecule of any one of claims 41-74, 77-127, 142, 143, 150, and 151, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 1346 operatively linked to the sequence of SEQ ID NO: 5048;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5028 operatively linked to the sequence of SEQ ID NO: 5050; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 1349 operatively linked to the sequence of SEQ ID NO: 3644.

153. The multispecific molecule of claim 152, wherein the sequence of SEQ ID NO: 5028 is operatively linked to the sequence of SEQ ID NO: 5050 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

154. The multispecific molecule of claim 42, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5057;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of 5066; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5059.

155. The multispecific molecule of claim 154, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 5057;(ii) a second polypeptide chain comprising the sequence of 5066; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 5059.

156. The multispecific molecule of any one of claims 41-74 and 77-127, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising a VH of the first domain,WSGR Docket No. 53676-759.601 wherein the first domain comprises an antibody molecule or an antigen binding domain that binds to a TCRpV region, and wherein the VH is operatively linked to a first Fc region;(ii) a second polypeptide chain comprising the second domain comprising the IL-21 mutein polypeptide, wherein the IL-21 mutein polypeptide comprises a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, and the IL-21 mutein polypeptide comprises an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu; and wherein the second domain is operatively linked to a second Fc region; and(iii) a third polypeptide chain comprising a VL of the first domain, wherein the VL is operatively linked to a light chain constant region; wherein the VH of the first domain and the VL of the first domain are assembled and form the first domain.

157. The multispecific molecule of claim 156, wherein the second domain is operatively linked to the second Fc region via a linker sequence.

158. The multispecific molecule of any one of claims 41-74, 77-127, 156, and 157, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1346 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5044;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5035 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5046; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1349 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 3644.

159. The multispecific molecule of claim 158, wherein the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5035 is operatively linked to the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5046 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

160. The multispecific molecule of any one of claims 41-74, 77-127, and 156-159, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 1346 operatively linked to the sequence of SEQ ID NO: 5044;WSGR Docket No. 53676-759.601(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5035 operatively linked to the sequence of SEQ ID NO: 5046; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 1349 operatively linked to the sequence of SEQ ID NO: 3644.

161. The multispecific molecule of claim 160, wherein the sequence of SEQ ID NO: 5035 is operatively linked to the sequence of SEQ ID NO: 5046 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

162. The multispecific molecule of claim 42, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5055;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5068; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5059.

163. The multispecific molecule of claim 162, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 5055;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5068; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 5059.

164. The multispecific molecule of any one of claims 41-74, 77-127, 156, and 157, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1346 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5048;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5035 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5050; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1349 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 3644.

165. The multispecific molecule of claim 164, wherein the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5035 is operatively linked to the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5050 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

166. The multispecific molecule of any one of claims 41-74, 77-127, 156, 157, 164, and 165, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 1346 operatively linked to the sequence of SEQ ID NO: 5048;WSGR Docket No. 53676-759.601(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5035 operatively linked to the sequence of SEQ ID NO: 5050; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 1349 operatively linked to the sequence of SEQ ID NO: 3644.

167. The multispecific molecule of claim 166, wherein the sequence of SEQ ID NO: 5035 is operatively linked to the sequence of SEQ ID NO: 5050 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

168. The multispecific molecule of claim 42, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5057;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of 5070; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5059.

169. The multispecific molecule of claim 168, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 5057;(ii) a second polypeptide chain comprising the sequence of 5070; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 5059.

170. The multispecific molecule of any one of claims 41-74 and 77-127, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising a VH of the first domain, wherein the first domain comprises an antibody molecule or an antigen binding domain that binds to a TCRpV region, and wherein the VH is operatively linked to a first Fc region;(ii) a second polypeptide chain comprising the second domain comprising the IL-21 mutein polypeptide, wherein the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5036; and wherein the second domain is operatively linked to a second Fc region; and(iii) a third polypeptide chain comprising a VL of the first domain, wherein the VL is operatively linked to a light chain constant region; wherein the VH of the first domain and the VL of the first domain are assembled and form the first domain.

171. The multispecific molecule of claim 170, wherein the second domain is operatively linked to the second Fc region via a linker sequence.

172. The multispecific molecule of any one of claims 41-74, 77-127, 170, and 171, wherein the multispecific molecule comprises:WSGR Docket No. 53676-759.601(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1346 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5044;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5036 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5046; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1349 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 3644.

173. The multispecific molecule of claim 172, wherein the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5036 is operatively linked to the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5046 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

174. The multispecific molecule of any one of claims 41-74, 77-127, and 170-173, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 1346 operatively linked to the sequence of SEQ ID NO: 5044;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5036 operatively linked to the sequence of SEQ ID NO: 5046; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 1349 operatively linked to the sequence of SEQ ID NO: 3644.

175. The multispecific molecule of claim 174, wherein the sequence of SEQ ID NO: 5036 is operatively linked to the sequence of SEQ ID NO: 5046 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

176. The multispecific molecule of claim 42, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5055;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5072; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5059.

177. The multispecific molecule of claim 176, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 5055;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5072; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 5059.

178. The multispecific molecule of any one of claims 41-74, 77-127, 170, and 171, wherein the multispecific molecule comprises:WSGR Docket No. 53676-759.601(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1346 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5048;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5036 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5050; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 1349 operatively linked to a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 3644.

179. The multispecific molecule of claim 178, wherein the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5036 is operatively linked to the sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5050 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

180. The multispecific molecule of any one of claims 41-74, 77-127, 170, 171, 178, and 179, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 1346 operatively linked to the sequence of SEQ ID NO: 5048;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5036 operatively linked to the sequence of SEQ ID NO: 5050; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 1349 operatively linked to the sequence of SEQ ID NO: 3644.

181. The multispecific molecule of claim 180, wherein the sequence of SEQ ID NO: 5036 is operatively linked to the sequence of SEQ ID NO: 5050 via a linker sequence comprising the sequence of SEQ ID NO: 3308.

182. The multispecific molecule of claim 42, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5057;(ii) a second polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5074; and(iii) a third polypeptide chain comprising a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5059.

183. The multispecific molecule of claim 182, wherein the multispecific molecule comprises:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 5057;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5074; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 5059.

184. The multispecific molecule of any one of claims 41-183, wherein the multispecific molecule further comprises a tumor-targeting moiety that binds to a cancer antigen present on a cancer.WSGR Docket No. 53676-759.601185. The multispecific molecule of claim 184, wherein the tumor-targeting moiety comprises an antibody molecule that binds to a cancer antigen, a receptor or receptor fragment or variant thereof that binds to a cancer antigen, a ligand or functional fragment or variant thereof that binds to a cancer antigen, or any combination thereof.

186. Hie multispecific molecule of claim 184 or 185, wherein the cancer antigen is a tumor antigen, a stromal antigen, or a hematological antigen.

187. The multispecific molecule of any one of claims 184-186, wherein the cancer antigen is selected from the group consisting of: BCMA, FcRH5, CD19, CD20, CD22, CD30, CD33, CD38, CD3, CD47, CD99, CD123, CLEC12, CD179A, SLAMF7, PDL1, gangloside 2 (GD2), prostate stem cell antigen (PSCA), prostate specific membrane antigen (PSMA), prostate-specific antigen (PSA), carcinoembryonic antigen (CEA), Ron Kinase, c-Met, Immature laminin receptor, TAG-72, BING- 4, Calcium -activated chloride channel 2, Cyclin-Bl, 9D7, Ep-CAM, EphA3, Her2 / neu, Telomerase, SAP-1, Survivin, NY-ESO-l / LAGE-1, PRAME, SSX-2, Melan-A / MART-1, Gpl00 / pmell7, Tyrosinase, MC1R, b-catenin, BRCA1 / 2, CDK4, CML66, Fibronectin, p53, Ras, TGF-B receptor, AFP, ETA, MAGE, CA-125, BAGE, GAGE, CDC27, actinin-4, TRPl / gp75, TRP2, WT1, Epidermal growth factor receptor (EGFR), MART-2, MUC1, MUC2, MUM1, MUM2, MUM3, NA88-1, NPM, OA1, OGT, RCC, RU11, RU12, SAGE, TRG, TSTA, Folate receptor alpha, LI- CAM, CAIX, gpA33, GD3, GM2, VEGFR, an Integrin, a carbohydrate, IGF1R, TRAILR1, TRAILR2, RANKL, FAP, TGF-beta, hyaluronic acid, collagen, tenascin C, and tenascin W.

188. The multispecific molecule of any one of claims 184-187, wherein the cancer is a hematological cancer, a solid tumor, a metastatic cancer, a soft tissue tumor, or any combination thereof.

189. The multispecific molecule of any one of claims 184-188, wherein the cancer is a solid tumor selected from the group consisting of colon cancer, pancreatic cancer, breast cancer, colorectal cancer, lung cancer, skin cancer, ovarian cancer, liver cancer, renal cancer, melanoma, prostate cancer, rectal cancer, cervical cancer, or any combination thereof.

190. The multispecific molecule of any one of claims 184-189, wherein the cancer is a solid tumor selected from the group consisting of an anti-PDl therapy resistant solid cancer, an HPV-positive solid cancer, a cancer with a high tumor mutation burden, or any combination thereof.

191. The multispecific molecule of any one of claims 184-188, wherein the cancer is a hematological cancer comprising a B-cell malignancy or a T cell malignancy.

192. The multispecific molecule of claim 191, wherein the B-cell malignancy or the T cell malignancy is selected from the group consisting of Hodgkin’s lymphoma, Non-Hodgkin’s lymphoma, acute myeloid leukemia (AML), chronic myeloid leukemia, myelodysplastic syndrome, multiple myeloma, and acute lymphocytic leukemia.

193. The multispecific molecule of claim 192, wherein the Non-Hodgkin's lymphomais selected from the group consisting of B cell lymphoma, diffuse large B cell lymphoma, follicular lymphoma, chronic lymphocytic leukemia, mantle cell lymphoma, marginal zone B-cell lymphoma, Burkitt lymphoma, lymphoplasmacytic lymphoma, and hairy cell leukemia.WSGR Docket No. 53676-759.601194. The multispecific molecule of any one of claims 41-193, wherein the multispecific molecule further comprises an immune cell engager.

195. The multispecific molecule of claim 194, wherein the immune cell engager is an NK cell engager, a T cell engager, a B cell engager, a dendritic cell engager, or a macrophage cell engager.

196. The multispecific molecule of any one of claims 56-195, wherein when contacted to the T cell population, the multispecific molecule redirects the T cell to a target cell, expands the T cell, and / or activates the T cell.

197. The multispecific molecule of claim 196, wherein the target cell is a cancer cell or T cells in the T cell population.

198. The multispecific molecule of claim 196, wherein the T cell expansion occurs in vivo.

199. The multispecific molecule of claim 196, wherein the T cell expansion occurs ex vivo.

200. The multispecific molecule of any one of claims 41-199, wherein when contacted to the T cell population, the multispecific molecule promotes T cells of the T cell population to kill cancer cells.

201. The multispecific molecule of claim 200, wherein the T cells comprise NK-T cells.

202. The multispecific molecule of claim 200, wherein the T cells comprise CD4+ T cells.

203. The multispecific molecule of claim 200, wherein the T cells comprise CD8+ T cells.

204. The multispecific molecule of claim 200, wherein the T cells comprise CD25+ T cells.

205. The multispecific molecule of claim 200, wherein the T cells comprise TCRVP+ T cells.

206. The multispecific molecule of any one of claims 41-205, wherein when contacted to the T cell population, the multispecific molecule promotes production of Granzyme B (GzB) as compared to a T cell population not contacted with the multispecific molecule.

207. The multispecific molecule of any one of claims 41-206, wherein when contacted to the T cell population, the multispecific molecule promotes production of one or more cytokines as compared to a T cell population not contacted with the multispecific molecule.

208. The multispecific molecule of claim 207, wherein the one or more cytokines comprises interferon gamma (IFNy), interleukin- 1 beta (IL-ip), interleukin-6 (IL-6), interleukin- 10 (IL-10), tumor necrosis factor alpha (TNF-a), or a combination thereof.

209. A composition comprising the multispecific molecule of any one of claims 41-208.

210. A recom binant polynucleotide comprising a sequence encoding the IL-21 mutein polypeptide of the composition of any one of claims 1-40 or the multispecific molecule of any one of claims 41-208.

211. A vector comprising the recombinant polynucleotide of claim 210.

212. A cell comprising the recombinant polynucleotide of claim 210 or the vector of claim 211.

213. A method of making the multispecific molecule of any one of claims 41-208, comprising culturing a host cell comprising a recombinant polynucleotide comprising a sequence encoding the multispecific molecule or a vector comprising the recombinant polynucleotide under conditions suitable for gene expression and / or homo- or heterodimerization.WSGR Docket No. 53676-759.601214. A pharmaceutical composition comprising the IL-21 mutein polypeptide of the composition of any one of claims 1-40, the multispecific molecule of any one of claims 41-208, or the composition of claim 209, and a pharmaceutically acceptable carrier, excipient, or diluent.

215. A method of treating cancer in a subject in need thereof comprising: administering a therapeutically effective amount of the multispecific molecule of any one of claims 41 -208, the composition of claim 209, or the pharmaceutical composition of claim 214 to the subject, thereby treating the cancer in the subject.

216. Use of the multispecific molecule of any one of claims 41-208, the composition of claim 209, or the pharmaceutical composition of claim 214 in treating cancer in a subject in need thereof, wherein the multispecific molecule, the composition, or the pharmaceutical composition is formulated for administration in therapeutically effective amount to treat cancer in the subject.

217. The m ethod of claim 215, or the use of claim 216, wherein the subj ect is human.

218. Hie method of claim 215 or 217, or the use of claim 216 or 217, wherein the cancer is a solid tumor, a hematological cancer, a metastatic cancer, a soft tissue tumor, or a combination thereof.

219. The method of any one of claims 215, 217, and 218, or the use of any one of claims 216-218, wherein the cancer is a solid tumor selected from the group consisting of colon cancer, pancreatic cancer, breast cancer, colorectal cancer, lung cancer, skin cancer, ovarian cancer, liver cancer, renal cancer, melanoma, prostate cancer, rectal cancer, cervical cancer, or any combination thereof.

220. The method of tiny one of claims 215 and 217-219, orthe use of any one of claims 216-219, wherein the cancer is a solid tumor selected from the group consisting of an anti-PDl therapy resistant solid cancer, an HPV-positive solid cancer, a cancer with a high tumor mutation burden, or any combination thereof.

221. The method of any one of claims 215, 217, and 218, orthe use of any one of claims 216-218, wherein the cancer is a hematological cancer comprising a B-cell malignancy or a T cell malignancy.

222. The method or the use of claim 221, wherein the B-cell malignancy or the T cell malignancy is selected from the group consisting of Hodgkin’s lymphoma, Non-Hodgkin’s lymphoma, acute myeloid leukemia (AML), chronic myeloid leukemia, myelodysplastic syndrome, multiple myeloma, and acute lymphocytic leukemia.

223. The method or the use of claim 222, wherein the Non-Hodgkin's lymphoma is selected from the group consisting of B cell lymphoma, diffuse large B cell lymphoma, follicular lymphoma, chronic lymphocytic leukemia, mantle cell lymphoma, marginal zone B-cell lymphoma, Burkitt lymphoma, lymphoplasmacytic lymphoma, and hairy cell leukemia.

224. The method of any one of claims 215 and 217-223, orthe use of any one of claims 216-223, wherein before administration of the composition, a sample from the subject has an increased level or activity of one or more TCRpV subfamilies relative to a sample from a subject who does not have a cancer.

225. The method of any one of claims 215 and 217-224, wherein the method further comprises administering the multispecific molecule, the composition, or the pharmaceutical composition in combination with an immune checkpoint inhibitor.WSGR Docket No. 53676-759.601226. The use of any one of claims 216-224, wherein the multispecific molecule, the composition, or the pharmaceutical composition is formulated to be used in combination with an immune checkpoint inhibitor.

227. The method of claim 225, or the use of claim 226, wherein the immune checkpoint inhibitor is a PD- 1 inhibitor or a PD-L1 inhibitor.

228. The method of claim 225 or 227, or the use of claim 226 or 227, wherein the immune checkpoint inhibitor is a PD- 1 inhibitor selected from the group consisting of Nivolumab, Pembrolizumab, Pidilizumab, AMP 514, immunoadhesin, and AMP-224.

229. The method of claim 225 or 227, or the use of claim 226 or 227, wherein the immune checkpoint inhibitor is a PD-L1 inhibitor selected from the group consisting of MPDL3280A, MEDI-4736, MSB-0010718C, MSB0010718C, and YW243.55.S70.

230. The method of any one of claims 215 and 217-229, orthe use of any one of claims 216-229, wherein the multispecific molecule is not immobilized to a solid-phase.

231. The method of any one of claims 215 and 217-229, or the use of any one of claims 216-229, wherein the multispecific molecule is immobilized to a solid-phase.

232. A method of expanding and / or activating T cells that expresses a T cell receptor (TCR) comprising a T cell receptor beta (TCRP) comprising a T cell receptor beta variable region (TCRpV) in a T cell population comprising: contacting the T cell population with the multispecific molecule of any one of claims 41-208, the composition of claim 209, or the pharmaceutical composition of claim 214 in an effective amount, thereby expanding and / or activating the T cells in the T cell population.

233. Use of the multispecific molecule of any one of claims 41-208, the composition of claim 209, or the pharmaceutical composition of claim 214 for expanding and / or activating T cells that expresses a T cell receptor (TCR) comprising a T cell receptor beta (TCRP) comprising a T cell receptor beta variable region (TCRpV) in a T cell population by contacting the T cell population with the multispecific molecule, the composition, or the pharmaceutical composition in an effective amount, thereby expanding and / or activating the T cells in the T cell population.

234. The method of claim 232 or the use of claim 233, wherein the expansion and / or activation is selective expansion and / or activation of a subset of T cells that express a TCR comprising a TCRP that comprises a TCRpV region subfamily member to which the first domain binds in the T cell population.

235. 'the method of claim 232 or 234, or the use of claim 233 or 234, wherein the expansion and / or activation occurs in vivo.

236. The method of claim 232 or 234, or the use of claim 233 or 234, wherein the expansion and / or activation occurs ex vivo.Til . The method of tiny one of claims 232 and 234-236, orthe use of any one of claims 233-236, wherein the T cell population is a population of T cells in a biological sample from a subject.WSGR Docket No. 53676-759.601238. The method or the use of claim 237, wherein the biological sample comprises a blood sample, a biopsy sample, or a bone marrow sample.

239. The method or the use of claim 237 or 238, wherein the biological sample comprises a blood sample comprising a peripheral blood sample.

240. Hie method orthe use of claim 237 or 238, wherein the biological sample comprises a biopsy sample comprising a tumor biopsy sample.

241. The method of any one of claims 232 and 234-240, orthe use of any one of claims 233-240, wherein when contacted the T cell population, the multispecific molecule promotes T cells of the T cell population to kill cancer cells.

242. The method of tiny one of claims 232 and 234-241, orthe use of any one of claims 233-241, wherein the multispecific molecule is not immobilized to a solid-phase.

243. The method of any one of claims 232 and 234-241, orthe use of any one of claims 233-241, wherein the multispecific molecule is immobilized to a solid-phase.

244. A method of preparing an IL-21 mutein polypeptide comprising: preparing an IL-21 mutein polypeptide comprising a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193, and an aromatic amino acid substitution of He at position 8 of SEQ ID NO: 2193, wherein when expressed in a cell, the IL-21 mutein polypeptide is less susceptible to proteolytic cleavage compared to an IL-21 wild-type or variant polypeptide without the aromatic amino acid substitution of He at position 8 of SEQ ID NO: 2193 when expressed in a cell, thereby enhancing and / or prolong the activity of the IL-21 mutein polypeptide relative to the IL-21 wild-type or variant polypeptide.

245. A method of enhancing and / or prolong the activity of an IL-21 mutein comprising: introducing an aromatic amino acid substitution of He at position 8 of SEQ ID NO: 2193 to an IL-21 mutein polypeptide, wherein when expressed in a cell, the IL-21 mutein polypeptide is less susceptible to proteolytic cleavage compared to an IL-21 wild-type or variant polypeptide without the aromatic amino acid substitution of He at position 8 of SEQ ID NO: 2193 when expressed in a cell, thereby enhancing and / or prolong the activity of the IL-21 mutein polypeptide relative to the IL-21 wild-type or variant polypeptide.

246. The method of claim 245, wherein the IL-21 mutein polypeptide comprises a sequence having at least 85% sequence identity to the sequence of SEQ ID NO: 2193.

247. The method of any one of claims 244-246, wherein the IL-21 wild-type polypeptide comprises the sequence of SEQ ID NO: 2193.

248. The method of any one of claims 244-247, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe or Trp.

249. The method of any one of claims 244-248, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe.WSGR Docket No. 53676-759.601250. The method of any one of claims 244-248, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp.

251. The method of any one of claims 244-250, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, or any combination thereof.

252. The method of any one of claims 244-251, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu.

253. The method of any one of claims 244-252, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Lys.

254. The method of any one of claims 244-253, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu.

255. The method of any one of claims 244-249 and 251-253, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe, an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Lys, an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu.

256. The method of any one of claims 244-255, wherein the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5033.

257. The method of any one of claims 244-256, wherein the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5033.

258. The method of any one of claims 244-257, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193 with Thr, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193 with Gly, an amino acid substitution ofHis at position 120 of SEQ ID NO: 2193 with Asp, an amino acid substitution of Leu at position 123 of SEQ ID NO: 2193 with Thr, or any combination thereof.

259. The method of any one of claims 244-248, 250, and 258, wherein the IL-21 mutein polypeptide comprise an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, and an amino acid substitution ofHis at position 120 of SEQ ID NO: 2193 with Asp.

260. The method of any one of claims 244-248, 250, 258, and 259, wherein the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5025.

261. The method of any one of claims 244-248, 250, and 258-260, wherein the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5025.WSGR Docket No. 53676-759.601262. The method of any one of claims 244-249, and 253, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe, and an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Lys.

263. The method of any one of claims 244-249, 253, and 262, wherein the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5026.

264. The method of any one of claims 244-249, 253, 262, and 263, wherein the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5026.

265. The method of any one of claims 244-248, 250, and 258, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193 with Thr, and an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp.

266. The method of any one of claims 244-248, 250, 258, and 265, wherein the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5027.

267. The method of any one of claims 244-248, 250, 258, 265, and 266, wherein the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5027.

268. The method of any one of claims 244-248, 250-252, and 258, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193 with Gly, and an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp.

269. The method of any one of claims 244-248, 250-252, 258, and 268, wherein the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5029.

270. The method of any one of claims 244-248, 250-252, 258, 268, and 269, wherein the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5029.

271. The method of any one of claims 244-249 and 251-253, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Phe, an amino acid substitution of Asp at position 15 of SEQ ID NO: 2193 with Lys, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu.

272. The method of any one of claims 244-249, 251-253, and 271, wherein the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5030.WSGR Docket No. 53676-759.601273. The method of any one of claims 244-249, 251-253, 271, and 272 wherein the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5030.

274. The method of any one of claims 244-248, 250-252, and 258, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193 with Thr, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193 with Gly, an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp, and an amino acid substitution of Leu at position 123 of SEQ ID NO: 2193 with Thr.

275. The method of any one of claims 244-248, 250-252, 258, and 274, wherein the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5031.

276. The method of any one of claims 244-248, 250-252, 258, 274, and 275, wherein the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5031.

277. The method of any one of claims 244-248, 250-252, 254, and 258, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, and an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp.

278. The method of any one of claims 244-248, 250-252, 254, 258, and 277, wherein the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5032.

279. The method of any one of claims 244-248, 250-252, 254, 258, 277, and 278, wherein the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5032.

280. The method of any one of claims 244-248, 250-252, 254, and 258, wherein the IL-21 mutein polypeptide comprises an amino acid substitution of He at position 8 of SEQ ID NO: 2193 with Trp, an amino acid substitution of Lys at position 73 of SEQ ID NO: 2193 with Thr, an amino acid substitution of Lys at position 77 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 85 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Arg at position 86 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Lys at position 88 of SEQ ID NO: 2193 with Glu, an amino acid substitution of Leu at position 91 of SEQ ID NO: 2193 with Gly, an amino acid substitution of His at position 120 of SEQ ID NO: 2193 with Asp, and an amino acid substitution of Leu at position 123 of SEQ ID NO: 2193 with Thr.WSGR Docket No. 53676-759.601281. The method of any one of claims 244-248, 250-252, 254, 258, and 280, wherein the IL-21 mutein polypeptide comprises a sequence having at least 80% sequence identity to the sequence of SEQ ID NO: 5034.

282. The method of any one of claims 244-248, 250-252, 254, 258, 280, and 281, wherein the IL-21 mutein polypeptide comprises the sequence of SEQ ID NO: 5034.

283. A molecule comprising:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 5055;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5064; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 5059.

284. A molecule comprising:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 5057;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5066; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 5059.

285. A molecule comprising:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 5055;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5068; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 5059.

286. A molecule comprising:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 5057;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5070; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 5059.

287. A molecule comprising:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 5055;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5072; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 5059.

288. A molecule comprising:(i) a first polypeptide chain comprising the sequence of SEQ ID NO: 5057;(ii) a second polypeptide chain comprising the sequence of SEQ ID NO: 5074; and(iii) a third polypeptide chain comprising the sequence of SEQ ID NO: 5059.

289. One or more recombinant nucleic acids, wherein the one or more recombinant nucleic acids comprise a sequence encoding a first polypeptide chain, a sequence encoding a second polypeptide chain and a sequence encoding a third polypeptide chain, wherein:(i) the first polypeptide chain comprises the sequence of SEQ ID NO: 5055;(ii) the second polypeptide chain comprises the sequence of SEQ ID NO: 5064; and(iii) the third polypeptide chain comprises the sequence of SEQ ID NO: 5059.

290. One or more recombinant nucleic acids, wherein the one or more recombinant nucleic acids comprise a sequence encoding a first polypeptide chain, a sequence encoding a second polypeptide chain and a sequence encoding a third polypeptide chain, wherein:WSGR Docket No. 53676-759.601(i) the first polypeptide chain comprises the sequence of SEQ ID NO: 5057;(ii) the second polypeptide chain comprises the sequence of SEQ ID NO: 5066; and(iii) the third polypeptide chain comprises the sequence of SEQ ID NO: 5059.

291. One or more recombinant nucleic acids, wherein the one or more recombinant nucleic acids comprise a sequence encoding a first polypeptide chain, a sequence encoding a second polypeptide chain and a sequence encoding a third polypeptide chain, wherein:(i) the first polypeptide chain comprises the sequence of SEQ ID NO: 5055;(ii) the second polypeptide chain comprises the sequence of SEQ ID NO: 5068; and(iii) the third polypeptide chain comprises the sequence of SEQ ID NO: 5059.

292. One or more recombinant nucleic acids, wherein the one or more recombinant nucleic acids comprise a sequence encoding a first polypeptide chain, a sequence encoding a second polypeptide chain and a sequence encoding a third polypeptide chain, wherein:(i) the first polypeptide chain comprises the sequence of SEQ ID NO: 5057;(ii) the second polypeptide chain comprises the sequence of SEQ ID NO: 5070; and(iii) the third polypeptide chain comprises the sequence of SEQ ID NO: 5059.

293. One or more recombinant nucleic acids, wherein the one or more recombinant nucleic acids comprise a sequence encoding a first polypeptide chain, a sequence encoding a second polypeptide chain and a sequence encoding a third polypeptide chain, wherein:(i) the first polypeptide chain comprises the sequence of SEQ ID NO: 5055;(ii) the second polypeptide chain comprises the sequence of SEQ ID NO: 5072; and(iii) the third polypeptide chain comprises the sequence of SEQ ID NO: 5059.

294. One or more recombinant nucleic acids, wherein the one or more recombinant nucleic acids comprise a sequence encoding a first polypeptide chain, a sequence encoding a second polypeptide chain and a sequence encoding a third polypeptide chain, wherein:(i) the first polypeptide chain comprises the sequence of SEQ ID NO: 5057;(ii) the second polypeptide chain comprises the sequence of SEQ ID NO: 5074; and(iii) the third polypeptide chain comprises the sequence of SEQ ID NO: 5059.

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