Il-2 conjugates and methods of use for treating autoimmune diseases

Abstract

To provide interleukin (IL) conjugates useful for the treatment of one or more indications.SOLUTION: The IL-2 conjugate contains a specific amino acid sequence. At least one amino acid residue in the IL-2 conjugate is replaced with the structure of Formula (I): SELECTED DRAWING: Figure 5A

Description

[Technical Field]

[0001] This application claims the benefit of priority to U.S. Provisional Application No. 62 / 898,478, filed September 10, 2019, U.S. Provisional Application No. 62 / 900,488, filed September 14, 2019, U.S. Provisional Application No. 62 / 930,987, filed November 5, 2019, U.S. Provisional Application No. 62 / 953,075, filed December 23, 2019, and U.S. Provisional Application No. 63 / 042,393, filed June 22, 2020, the contents of each of which are incorporated herein by reference in their entirety for all purposes.

[0002] Sequence Listing This application is submitted with a Sequence Listing in electronic format. The Sequence Listing is provided as a file entitled "01183-0072-00PCT_ST25.txt," created on September 7, 2020, and 335,872 bytes in size. The information in the electronic format of the Sequence Listing is incorporated herein by reference in its entirety. [Background technology]

[0003] Introduction and Summary Distinct populations of T cells regulate the immune system to maintain immune homeostasis and immune tolerance. For example, regulatory T (Treg) cells prevent inappropriate responses by the immune system by preventing pathological autoreactivity. In some cases, modulation of distinct populations of T cells provides options for the treatment of diseases or indications. Summary of the Invention [Means for solving the problem]

[0004] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (I): [ka] (In the formula: Z is CH2 and Y is [ka] and; Y is CH2 and Z is [ka] and; Z is CH2 and Y is [ka] is; or Y is CH2 and Z is [ka] and; W is a PEG group having an average molecular weight selected from 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, and 60 kDa; X is of the structure: [ka] having; X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue) In some embodiments, the IL-2 conjugate is a pharmaceutically acceptable salt, solvate, or hydrate thereof. Further provided herein is an IL-2 conjugate wherein Z is CH2 and Y is replaced by [ka] Further provided herein is an IL-2 conjugate wherein Y is CH2 and Z is [ka] Further provided herein is an IL-2 conjugate, wherein Z is CH2 and Y is [ka] or a pharmaceutically acceptable salt, solvate, or hydrate thereof. Further provided herein is an IL-2 conjugate wherein Z is CH2 and Y is [ka] and W is a PEG group having an average molecular weight selected from 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, and 60 kDa. Further provided herein is an IL-2 conjugate wherein Y is CH2 and Z is [ka] Further provided herein is an IL-2 conjugate wherein the PEG group has an average molecular weight selected from 5 kDa, 10 kDa, 20 kDa, 30 kDa, 40 kDa, or 50 kDa. Further provided herein is an IL-2 conjugate wherein the PEG group has an average molecular weight of 5 kDa. Here and throughout, the embodiments of Z and Y also encompass pharmaceutically acceptable salts, solvates, or hydrates thereof. Further provided herein is an IL-2 conjugate wherein the PEG group has an average molecular weight of 30 kDa. Further provided herein is an IL-2 conjugate wherein the PEG group has an average molecular weight of 35 kDa. Further provided herein is an IL-2 conjugate wherein the PEG group has an average molecular weight of 40 kDa. Further provided herein is an IL-2 conjugate wherein the PEG group has an average molecular weight of 45 kDa. Further provided herein is an IL-2 conjugate wherein the PEG group has an average molecular weight of 50 kDa. Further provided herein is an IL-2 conjugate wherein the PEG group has an average molecular weight of 55 kDa. Further provided herein is an IL-2 conjugate wherein the PEG group has an average molecular weight of 60 kDa.Further provided herein is a conjugate of formula (I) wherein the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is P1, T2, S3, S4, S5, T6, K7, K8, Q10, L11, E14, H15, L17, L18, D19, Q21, M22, N25, G26, N28, N29, Y30, K31, K34, T36, M45, P46, K47, A49, T50, E51, L52, K53, H54, Q56, E59, E66, N70, Q73, S74, K75, N76, F77, H78, R80, P 81, R82, D83, S86, N87, I88, V90, I91, L93, E94, K96, G97, S98, E99, T100, T101, F102, M103, C104, E105, Y106, A107, D108, D108, E109, T110, A111, T112, E115, N118, R119, T122, F123, S124, Q125, S126, S129, T130, L131, and T132 in the N87R variant. Further described herein are IL-2 conjugates, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is selected from K8, H15, L18, D19, M22, N25, N87, V90, I91, L93, E94, K96, G97, S98, E99, D108 in the N87R variant, N118, T122, S124, Q125, S126, S129, and T130. Further described herein are IL-2 conjugates, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is selected from K8, H15, L18, D19, M22, N25, N87, V90, E99, D108 in the N87R variant, N118, T122, S124, and T130. Further described herein are IL-2 conjugates, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is K8. Further described herein are IL-2 conjugates, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is H15. Further described herein are IL-2 conjugates, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is L18.Further described herein is an IL-2 conjugate, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is D19. Further described herein is an IL-2 conjugate, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is M22. Further described herein is an IL-2 conjugate, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is N25. Further described herein is an IL-2 conjugate, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is N87. Further described herein is an IL-2 conjugate, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is V90. Further described herein is an IL-2 conjugate, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is E99. Further described herein is an IL-2 conjugate, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is D108 in the N87R variant. Further described herein is an IL-2 conjugate, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is N118. Further described herein is an IL-2 conjugate, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is T122. Further described herein is an IL-2 conjugate, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is S124. Further described herein is an IL-2 conjugate, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is T130.

[0005] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 4, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (I): [ka] (In the formula: Z is CH2 and Y is [ka] and; Y is CH2 and Z is [ka] and; Z is CH2 and Y is [ka] is; or Y is CH2 and Z is [ka] and; W is a PEG group having an average molecular weight selected from 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, and 60 kDa; X is of the structure: [ka] having; X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue) In some embodiments, the IL-2 conjugate is a pharmaceutically acceptable salt, solvate, or hydrate thereof. Further provided herein is an IL-2 conjugate wherein Z is CH2 and Y is replaced by [ka] Further provided herein is an IL-2 conjugate, wherein Y is CH2 and Z is [ka] Further provided herein is an IL-2 conjugate, wherein Z is CH2 and Y is [ka] Further provided herein is an IL-2 conjugate, wherein Z is CH2 and Y is [ka] and W is a PEG group having an average molecular weight selected from 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, and 60 kDa. Further provided herein is an IL-2 conjugate wherein Y is CH2 and Z is [ka] Further provided herein is an IL-2 conjugate wherein the PEG group has an average molecular weight selected from 5 kDa, 10 kDa, 20 kDa, 30 kDa, 40 kDa, or 50 kDa. Further provided herein is an IL-2 conjugate wherein the PEG group has an average molecular weight of 5 kDa. Further provided herein is an IL-2 conjugate wherein the PEG group has an average molecular weight of 30 kDa. Further provided herein is an IL-2 conjugate wherein the PEG group has an average molecular weight of 35 kDa. Further provided herein is an IL-2 conjugate wherein the PEG group has an average molecular weight of 40 kDa. Further provided herein is an IL-2 conjugate wherein the PEG group has an average molecular weight of 45 kDa. Further provided herein is an IL-2 conjugate wherein the PEG group has an average molecular weight of 50 kDa. Further provided herein is an IL-2 conjugate, wherein the PEG group has an average molecular weight of 55 kDa. Further provided herein is an IL-2 conjugate, wherein the PEG group has an average molecular weight of 60 kDa. Further provided herein is an IL-2 conjugate wherein the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is A1, P2, T3, S4, S5, S6, T7, K8, K9, Q11, L12, E15, H16, L18, L19, D20, Q22, M23, N26, G27, N29, N30, Y31, K32, K35, T37, M46, P47, K48, A50, T51, E52, L53, H55, Q57, E60, E67, N71, Q74, S75, K76, N77, F78, H79, R81 , P82, R83, D84, S87, N88, I89, V91, I92, L94, E95, K97, G98, S99, E100, T101, T102, F103, M104, C105, E106, Y107, A108, D109, D109 in the N88R variant, E110, T111, A112, T113, E116, N119, R120, T123, S125, Q126, S127, S130, T131, L132, and T133.Further described herein are IL-2 conjugates, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is selected from K9, H16, L19, D20, M23, N26, N88, V91, I92, L94, E95, K97, G98, S99, E100, D109 in the N88R variant, N119, T123, S125, Q126, S127, S130, and T131. Further described herein are IL-2 conjugates, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is selected from K9, H16, L19, D20, M23, N26, N88, V91, E100, D109 in the N88R variant, N119, T123, S125, and T131. Further described herein are IL-2 conjugates, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is K9. Further described herein are IL-2 conjugates, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is H16. Further described herein are IL-2 conjugates, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is L19. Further described herein is an IL-2 conjugate, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is D20. Further described herein is an IL-2 conjugate, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is M23. Further described herein is an IL-2 conjugate, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is N26. Further described herein is an IL-2 conjugate, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is N88. Further described herein is an IL-2 conjugate, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is V91. Further described herein is an IL-2 conjugate, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is E100.Further described herein is an IL-2 conjugate, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is D109 in the N88R variant. Further described herein is an IL-2 conjugate, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is N119. Further described herein is an IL-2 conjugate, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is T123. Further described herein is an IL-2 conjugate, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is S125. Further described herein is an IL-2 conjugate, wherein the position of the structure of Formula (I) in the amino acid sequence of the IL-2 conjugate is T131.

[0006] Described herein are IL-2 conjugates comprising the amino acid sequence of any one of SEQ ID NOs: 34-48, and 199-213, wherein [AzK_PEG] has the structure of Formula (II) or Formula (III), or a mixture of Formulas (II) and (III): [ka] (In the formula: W is a PEG group having an average molecular weight selected from 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, and 60 kDa; X is of the structure: [ka] having; X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue) In some embodiments, the IL-2 conjugate is a pharmaceutically acceptable salt, solvate, or hydrate thereof. Herein and throughout, embodiments of formula (II) and / or (III) also encompass pharmaceutically acceptable salts, solvates, or hydrates thereof. Further described herein is an IL-2 conjugate wherein [AzK_PEG] is a mixture of formula (II) and formula (III). Further described herein is an IL-2 conjugate wherein [AzK_PEG] is a mixture of formula (II) and formula (III). Further described herein is an IL-2 conjugate wherein [AzK_PEG] is a mixture of formula (II) and formula (III). [ka]

[0013] An IL-2 conjugate having the formula (II) is as follows:

[0014] Herein, and throughout, the structure of Formula (II) encompasses pharmaceutically acceptable salts, solvates, or hydrates thereof.

[0015] Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 34-48.

[0016] Further described herein is an IL-2 conjugate wherein W is a PEG group having an average molecular weight selected from 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, or 60 kDa.

[0017] Further described herein is an IL-2 conjugate wherein W is a PEG group having an average molecular weight selected from 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, or 60 kDa. Further described herein are IL-2 conjugates wherein W is a PEG group having an average molecular weight of 5 kDa. Further described herein are IL-2 conjugates wherein W is a PEG group having an average molecular weight of 30 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 35 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 40 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 45 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 50 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 55 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 60 kDa. Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 199-213. Further described herein is an IL-2 conjugate, wherein W is a PEG group having an average molecular weight selected from 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, or 60 kDa.Further described herein are IL-2 conjugates wherein W is a PEG group having an average molecular weight selected from 50 kDa and 30 kDa. Further described herein are IL-2 conjugates wherein W is a PEG group having an average molecular weight of 5 kDa. Further described herein are IL-2 conjugates wherein W is a PEG group having an average molecular weight of 30 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 35 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 40 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 45 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 50 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 55 kDa. Further provided herein is an IL-2 conjugate wherein the PEG group has an average molecular weight of 60 kDa. Further described herein is an IL-2 conjugate having the amino acid sequence of SEQ ID NO: 35 or 200. Further described herein is an IL-2 conjugate wherein W is a PEG group having an average molecular weight selected from 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, or 60 kDa. Further described herein is an IL-2 conjugate wherein W is a PEG group having an average molecular weight selected from 50 kDa and 30 kDa. Further described herein is an IL-2 conjugate wherein W is a PEG group having an average molecular weight of 5 kDa. Further described herein are IL-2 conjugates in which W is a PEG group having an average molecular weight of 30 kDa. Further provided herein are IL-2 conjugates in which the PEG group has an average molecular weight of 35 kDa. Further provided herein are IL-2 conjugates in which the PEG group has an average molecular weight of 40 kDa.Further provided herein is an IL-2 conjugate wherein the PEG group has an average molecular weight of 45 kDa. Further provided herein is an IL-2 conjugate wherein the PEG group has an average molecular weight of 50 kDa. Further provided herein is an IL-2 conjugate wherein the PEG group has an average molecular weight of 55 kDa. Further described herein is an IL-2 conjugate wherein the PEG group has an average molecular weight of 60 kDa. Further described herein is an IL-2 conjugate wherein [AzK_PEG] is a compound represented by formula (III): [ka]

[0013] An IL-2 conjugate having the structure:

[0014] wherein, and throughout, the structure of Formula (III) encompasses pharmaceutically acceptable salts, solvates, or hydrates thereof.

[0015] Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 34-48.

[0016] Further described herein is an IL-2 conjugate wherein W is a PEG group having an average molecular weight selected from 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, or 60 kDa.

[0017] Further described herein is an IL-2 conjugate wherein W is a PEG group having an average molecular weight selected from 50 kDa and 30 kDa.

[0018] Further described herein is an IL-2 conjugate wherein W is a PEG group having an average molecular weight of 5 kDa. Further described herein are IL-2 conjugates wherein W is a PEG group having an average molecular weight of 30 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 35 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 40 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 45 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 50 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 55 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 60 kDa. Further described herein are IL-2 conjugates having the amino acid sequence of any one of SEQ ID NOs: 199-213. Further described herein are IL-2 conjugates, wherein W is a PEG group having an average molecular weight selected from 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, or 60 kDa.Further described herein are IL-2 conjugates wherein W is a PEG group having an average molecular weight selected from 50 kDa and 30 kDa. Further described herein are IL-2 conjugates wherein W is a PEG group having an average molecular weight of 5 kDa. Further described herein are IL-2 conjugates wherein W is a PEG group having an average molecular weight of 30 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 35 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 40 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 45 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 50 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 55 kDa. Further provided herein is an IL-2 conjugate wherein the PEG group has an average molecular weight of 60 kDa. Further provided herein is an IL-2 conjugate wherein W is a linear or branched PEG group. Further provided herein is an IL-2 conjugate wherein W is a linear PEG group. Further provided herein is an IL-2 conjugate wherein W is a branched PEG group. Further provided herein is an IL-2 conjugate wherein W is a methoxy PEG group. Further described herein is an IL-2 conjugate wherein the methoxy PEG group is linear or branched. Further described herein is an IL-2 conjugate wherein the methoxy PEG group is linear. Further described herein is an IL-2 conjugate wherein the methoxy PEG group is branched.

[0007] Described herein are IL-2 conjugates comprising the amino acid sequence of any one of SEQ ID NOs: 49-63 and 214-228, wherein [AzK_PEG50kDa] has the structure of Formula (II) or Formula (III), or a mixture of Formulas (II) and (III): [ka] (In the formula: W is a PEG group having an average molecular weight of 50 kDa; X is of the structure: [ka] having; X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue) In some embodiments, the IL-2 conjugate is a pharmaceutically acceptable salt, solvate, or hydrate thereof. Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 49-63. Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 214-228. Further described herein is an IL-2 conjugate having the amino acid sequence of SEQ ID NO: 50 or 215. Further described herein is an IL-2 conjugate having the amino acid sequence of SEQ ID NO: 50 or 215. Further described herein is an IL-2 conjugate having the amino acid sequence of Formula (II) [ka] Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 49-63. Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 214-228. Further described herein is an IL-2 conjugate having the amino acid sequence of SEQ ID NO: 50 or 215. Further described herein is an IL-2 conjugate having the amino acid sequence of SEQ ID NO: 50 or 215. Further described herein is an IL-2 conjugate having the structure of formula (III): [ka] Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 49-63. Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 214-228. Further described herein is an IL-2 conjugate having the amino acid sequence of SEQ ID NO: 50 or 215.

[0008] Described herein are IL-2 conjugates comprising the amino acid sequence of any one of SEQ ID NOs: 64-78 and 229-243, wherein [AzK_PEG30kDa] has a structure of formula (II) or formula (III), or a mixture of the structures of formula (II) and formula (III): [ka] (In the formula: W is a PEG group having an average molecular weight of 30 kDa; X is of the structure: [ka] having; X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue) In some embodiments, the IL-2 conjugate is a pharmaceutically acceptable salt, solvate, or hydrate thereof. Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 64-78. Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 229-243. Further described herein is an IL-2 conjugate having the amino acid sequence of SEQ ID NO: 65 or 230. Further described herein is an IL-2 conjugate having the structure of Formula (II): [ka] Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 64-78. Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 229-243. Further described herein is an IL-2 conjugate having the amino acid sequence of SEQ ID NO: 65 or 230. Further described herein is an IL-2 conjugate having the amino acid sequence of SEQ ID NO: 65 or 230. Further described herein is an IL-2 conjugate having the amino acid sequence of formula (III) [ka] Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 64-78. Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 229-243. Further described herein is an IL-2 conjugate having the amino acid sequence of SEQ ID NO: 65 or 230.

[0009] Described herein are IL-2 conjugates comprising the amino acid sequence of any one of SEQ ID NOs: 34-48 and 199-213, wherein [AzK_PEG] is a mixture of structures of formula (II) and formula (III): [ka] (In the formula: W is a PEG group having an average molecular weight selected from 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, and 60 kDa; X is of the structure: [ka] having; X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue) In some embodiments, the IL-2 conjugate is a pharmaceutically acceptable salt, solvate, or hydrate thereof. Further described herein is an IL-2 conjugate, wherein the ratio of the amount of the structure of formula (II), including the total amount of [AzK_PEG], to the amount of the structure of formula (III) in the IL-2 conjugate is about 1:1. Further described herein is an IL-2 conjugate, wherein the ratio of the amount of the structure of formula (II), including the total amount of [AzK_PEG], to the amount of the structure of formula (III) in the IL-2 conjugate is greater than 1:1. Further described herein is an IL-2 conjugate, wherein the ratio of the amount of the structure of formula (II), including the total amount of [AzK_PEG], to the amount of the structure of formula (III) in the IL-2 conjugate is less than 1:1. Further described herein is an IL-2 conjugate, wherein W is a linear or branched PEG group. Further described herein are IL-2 conjugates wherein W is a linear PEG group. Further described herein are IL-2 conjugates wherein W is a branched PEG group. Further described herein are IL-2 conjugates wherein W is a methoxy PEG group. Further described herein are IL-2 conjugates wherein the methoxy PEG group is linear or branched. Further described herein are IL-2 conjugates wherein the methoxy PEG group is linear. Further described herein are IL-2 conjugates wherein the methoxy PEG group is branched.

[0010] Described herein is an IL-2 conjugate comprising the amino acid sequence of any one of SEQ ID NOs: 49-63 and 214-228, wherein [AzK_PEG50kDa] is a mixture of structures of formula (II) and formula (III): [ka] (In the formula: W is a PEG group having an average molecular weight of 50 kDa; X is of the structure: [ka] having; X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue) In some embodiments, the IL-2 conjugate is a pharmaceutically acceptable salt, solvate, or hydrate thereof. Further described herein is an IL-2 conjugate, wherein the ratio of the amount of the structure of Formula (II), including the total amount of [AzK_PEG50kDa] in the IL-2 conjugate, to the amount of the structure of Formula (III) is about 1:1. Further described herein is an IL-2 conjugate, wherein the ratio of the amount of the structure of Formula (II), including the total amount of [AzK_PEG50kDa] in the IL-2 conjugate, to the amount of the structure of Formula (III) is greater than 1:1. Further described herein is an IL-2 conjugate, wherein the ratio of the amount of the structure of Formula (II), including the total amount of [AzK_PEG50kDa] in the IL-2 conjugate, to the amount of the structure of Formula (III) is less than 1:1.

[0011] Described herein is an IL-2 conjugate comprising the amino acid sequence of any one of SEQ ID NOs: 64-78 and 229-243, wherein [AzK_PEG30kDa] is a mixture of structures of formula (II) and formula (III): [ka] (In the formula: W is a PEG group having an average molecular weight of 30 kDa; X is of the structure: [ka] having; X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue) In some embodiments, the IL-2 conjugate is a pharmaceutically acceptable salt, solvate, or hydrate thereof. Further described herein is an IL-2 conjugate, wherein the ratio of the amount of the structure of Formula (II), including the total amount of [AzK_PEG30kDa] in the IL-2 conjugate, to the amount of the structure of Formula (III) is about 1:1. Further described herein is an IL-2 conjugate, wherein the ratio of the amount of the structure of Formula (II), including the total amount of [AzK_PEG30kDa] in the IL-2 conjugate, to the amount of the structure of Formula (III) is greater than 1:1. Further described herein is an IL-2 conjugate, wherein the ratio of the amount of the structure of Formula (II), including the total amount of [AzK_PEG30kDa] in the IL-2 conjugate, to the amount of the structure of Formula (III) is less than 1:1.

[0012] Described herein are IL-2 conjugates comprising the amino acid sequence of any one of SEQ ID NOs: 154-168 and 109-123, wherein [AzK_L1_PEG] has the structure of Formula (IV) or Formula (V), or a mixture of Formulas (IV) and (V): [ka] (In the formula: W is a PEG group having an average molecular weight selected from 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, and 60 kDa; X is of the structure: [ka] having; X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue) In some embodiments, the IL-2 conjugate is a pharmaceutically acceptable salt, solvate, or hydrate thereof. Herein and throughout, embodiments of formula (IV) and / or (V) also encompass pharmaceutically acceptable salts, solvates, or hydrates thereof. Further described herein is an IL-2 conjugate wherein [AzK_L1_PEG] is a mixture of formula (IV) and formula (V). Further described herein is an IL-2 conjugate wherein [AzK_L1_PEG] has the structure of formula (IV): [ka]

[0013] An IL-2 conjugate having the formula (IV) is as follows:

[0014] Herein, and throughout, the structure of formula (IV) encompasses pharmaceutically acceptable salts, solvates, or hydrates thereof.

[0015] Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 109-123.

[0016] Further described herein is an IL-2 conjugate wherein W is a PEG group having an average molecular weight selected from 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, or 60 kDa.

[0017] Further described herein is an IL-2 conjugate wherein W is a PEG group having an average molecular weight selected from 50 kDa and 30 kDa.

[0018] Further described herein is an IL-2 conjugate wherein W is a PEG group having an average molecular weight of 5 kDa. Further described herein are IL-2 conjugates wherein W is a PEG group having an average molecular weight of 30 kDa. Further described herein are IL-2 conjugates having the amino acid sequence of SEQ ID NO: 155 or 110. Further described herein are IL-2 conjugates wherein W is a PEG group having an average molecular weight selected from 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, or 60 kDa. Further described herein are IL-2 conjugates wherein W is a PEG group having an average molecular weight selected from 5 kDa and 30 kDa. Further described herein are IL-2 conjugates wherein W is a PEG group having an average molecular weight of 5 kDa. Further described herein are IL-2 conjugates in which W is a PEG group having an average molecular weight of 30 kDa. Further provided herein are IL-2 conjugates in which the PEG group has an average molecular weight of 35 kDa. Further provided herein are IL-2 conjugates in which the PEG group has an average molecular weight of 40 kDa. Further provided herein are IL-2 conjugates in which the PEG group has an average molecular weight of 45 kDa.Further provided herein is an IL-2 conjugate, wherein the PEG group has an average molecular weight of 50 kDa. Further provided herein is an IL-2 conjugate, wherein the PEG group has an average molecular weight of 55 kDa. Further provided herein is an IL-2 conjugate, wherein the PEG group has an average molecular weight of 60 kDa. Further described herein is an IL-2 conjugate, wherein [AzK_L1_PEG] is a compound represented by formula (V): [ka]

[0013] An IL-2 conjugate having the structure:

[0014] wherein, and throughout, the structure of Formula (V) encompasses pharmaceutically acceptable salts, solvates, or hydrates thereof. Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 109-123. Further described herein is an IL-2 conjugate wherein W is a PEG group having an average molecular weight selected from 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, or 60 kDa. Further described herein is an IL-2 conjugate wherein W is a PEG group having an average molecular weight selected from 50 kDa and 30 kDa. Further described herein is an IL-2 conjugate wherein W is a PEG group having an average molecular weight of 5 kDa. Further described herein are IL-2 conjugates wherein W is a PEG group having an average molecular weight of 30 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 35 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 40 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 45 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 50 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 55 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 60 kDa. Further described herein are IL-2 conjugates having the amino acid sequence of SEQ ID NO: 155 or 110. Further described herein are IL-2 conjugates, wherein W is a PEG group having an average molecular weight selected from 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, or 60 kDa.Further described herein are IL-2 conjugates wherein W is a PEG group having an average molecular weight selected from 50 kDa and 30 kDa. Further described herein are IL-2 conjugates wherein W is a PEG group having an average molecular weight of 5 kDa. Further described herein are IL-2 conjugates wherein W is a PEG group having an average molecular weight of 30 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 35 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 40 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 45 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 50 kDa. Further provided herein are IL-2 conjugates wherein the PEG group has an average molecular weight of 55 kDa. Further provided herein is an IL-2 conjugate wherein the PEG group has an average molecular weight of 60 kDa. Further described herein is an IL-2 conjugate wherein W is a linear or branched PEG group. Further described herein is an IL-2 conjugate wherein W is a linear PEG group. Further described herein is an IL-2 conjugate wherein W is a branched PEG group. Further described herein is an IL-2 conjugate wherein W is a methoxy PEG group. Further described herein is an IL-2 conjugate wherein the methoxy PEG group is linear or branched. Further described herein is an IL-2 conjugate wherein the methoxy PEG group is linear. Further described herein is an IL-2 conjugate wherein the methoxy PEG group is branched.

[0013] Described herein are IL-2 conjugates comprising the amino acid sequence of any one of SEQ ID NOs: 169-183 and 124-138, wherein [AzK_L1_PEG50kDa] has the structure of Formula (IV) or Formula (V), or a mixture of Formulas (IV) and (V): [ka] (In the formula: W is a PEG group having an average molecular weight of 50 kDa; X is of the structure: [ka] having; X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue) In some embodiments, the IL-2 conjugate is a pharmaceutically acceptable salt, solvate, or hydrate thereof. Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 169-183. Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 124-138. Further described herein is an IL-2 conjugate having the amino acid sequence of SEQ ID NO: 170 or 125. Further described herein is an IL-2 conjugate having the amino acid sequence of SEQ ID NO: 170 or 125. Further described herein is an IL-2 conjugate having the amino acid sequence of formula (IV): [ka] Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 169-183. Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 124-138. Further described herein is an IL-2 conjugate having the amino acid sequence of SEQ ID NO: 170 or 125. Further described herein is an IL-2 conjugate having the amino acid sequence of SEQ ID NO: 170 or 125. Further described herein is an IL-2 conjugate having the structure of formula (V) [ka] Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 169-183. Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 124-138. Further described herein is an IL-2 conjugate having the amino acid sequence of SEQ ID NO: 170 or 125.

[0014] Described herein are IL-2 conjugates comprising the amino acid sequence of any one of SEQ ID NOs: 184-198 and 139-153, wherein [AzK_L1_PEG30kDa] has the structure of formula (IV) or formula (V), or a mixture of the structures of formula (IV) and formula (V): [ka] (In the formula: W is a PEG group having an average molecular weight of 30 kDa; X is of the structure: [ka] having; X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue) In some embodiments, the IL-2 conjugate is a pharmaceutically acceptable salt, solvate, or hydrate thereof. Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 184-198. Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 139-153. Further described herein is an IL-2 conjugate having the amino acid sequence of SEQ ID NO: 185 or 140. Further described herein is an IL-2 conjugate having the structure of formula (IV): [ka] Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 184-198. Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 139-153. Further described herein is an IL-2 conjugate having the amino acid sequence of SEQ ID NO: 185 or 140. Further described herein is an IL-2 conjugate having the amino acid sequence of SEQ ID NO: 185 or 140. Further described herein is an IL-2 conjugate having the amino acid sequence of formula (V) [ka] Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 184-198. Further described herein is an IL-2 conjugate having the amino acid sequence of any one of SEQ ID NOs: 139-153. Further described herein is an IL-2 conjugate having the amino acid sequence of SEQ ID NO: 185 or 140.

[0015] Described herein are IL-2 conjugates comprising the amino acid sequence of any one of SEQ ID NOs: 154-168 and 109-123, wherein [Azk_L1_PEG] is a mixture of structures of formula (IV) and formula (V): [ka] (In the formula: W is a PEG group having an average molecular weight selected from 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, and 60 kDa; X is of the structure: [ka] having; X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue) In some embodiments, the IL-2 conjugate is a pharmaceutically acceptable salt, solvate, or hydrate thereof. Further described herein is an IL-2 conjugate, wherein the ratio of the amount of the structure of Formula (IV), including the total amount of [AzK_L1_PEG], to the amount of the structure of Formula (V) in the IL-2 conjugate is about 1:1. Further described herein is an IL-2 conjugate, wherein the ratio of the amount of the structure of Formula (IV), including the total amount of [AzK_L1_PEG], to the amount of the structure of Formula (V) in the IL-2 conjugate is greater than 1:1. Further described herein is an IL-2 conjugate, wherein the ratio of the amount of the structure of Formula (IV), including the total amount of [AzK_L1_PEG], to the amount of the structure of Formula (V) in the IL-2 conjugate is less than 1:1. Further described herein are IL-2 conjugates wherein W is a linear or branched PEG group. Further described herein are IL-2 conjugates wherein W is a linear PEG group. Further described herein are IL-2 conjugates wherein W is a branched PEG group. Further described herein are IL-2 conjugates wherein W is a methoxy PEG group. Further described herein are IL-2 conjugates wherein the methoxy PEG group is linear or branched. Further described herein are IL-2 conjugates wherein the methoxy PEG group is linear. Further described herein are IL-2 conjugates wherein the methoxy PEG group is branched.

[0016] Described herein is an IL-2 conjugate comprising the amino acid sequence of any one of SEQ ID NOs: 169-183 and 124-138, wherein [AzK_L1_PEG50kDa] is a mixture of structures of formula (IV) and formula (V): [ka] (In the formula: W is a PEG group having an average molecular weight of 50 kDa; X is of the structure: [ka] having; X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue) In some embodiments, the IL-2 conjugate is a pharmaceutically acceptable salt, solvate, or hydrate thereof. Further described herein is an IL-2 conjugate, wherein the ratio of the amount of the structure of formula (IV), including the total amount of [AzK_L1_PEG50kDa] in the IL-2 conjugate, to the amount of the structure of formula (V) is about 1:1. Further described herein is an IL-2 conjugate, wherein the ratio of the amount of the structure of formula (IV), including the total amount of [AzK_L1_PEG50kDa] in the IL-2 conjugate, to the amount of the structure of formula (V) is greater than 1:1. Further described herein is an IL-2 conjugate, wherein the ratio of the amount of the structure of formula (IV), including the total amount of [AzK_L1_PEG50kDa] in the IL-2 conjugate, to the amount of the structure of formula (V) is less than 1:1.

[0017] Described herein is an IL-2 conjugate comprising the amino acid sequence of any one of SEQ ID NOs: 184-198 and 139-153, wherein [AzK_L1 PEG30kDa] is a mixture of structures of formula (IV) and formula (V): [ka] (In the formula: W is a PEG group having an average molecular weight of 30 kDa; X is of the structure: [ka] having; X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue) In some embodiments, the IL-2 conjugate is a pharmaceutically acceptable salt, solvate, or hydrate thereof. Further described herein is an IL-2 conjugate, wherein the ratio of the amount of the structure of Formula (IV), including the total amount of [AzK_L1_PEG30kDa] in the IL-2 conjugate, to the amount of the structure of Formula (V) is about 1:1. Further described herein is an IL-2 conjugate, wherein the ratio of the amount of the structure of Formula (IV), including the total amount of [AzK_L1_PEG30kDa] in the IL-2 conjugate, to the amount of the structure of Formula (V) is greater than 1:1. Further described herein is an IL-2 conjugate, wherein the ratio of the amount of the structure of Formula (IV), including the total amount of [AzK_L1_PEG30kDa] in the IL-2 conjugate, to the amount of the structure of Formula (V) is less than 1:1.

[0018] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (VI) or (VII), or a mixture of (VI) and (VII): [ka] (In the formula: n is an integer ranging from about 2 to about 5000; X is of the structure: [ka] having; X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue) In some embodiments, the IL-2 conjugate is a pharmaceutically acceptable salt, solvate, or hydrate thereof. Herein and throughout, embodiments of Formula (VI) and / or (VII) also include pharmaceutically acceptable salts, solvates, or hydrates thereof. Further described herein is a conjugate of IL-2, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the conjugate is P1, T2, S3, S4, S5, T6, K7, K8, Q10, L11, E14, H15, L17, L18, D19, Q21, M22, N25, G26, N28, N29, Y30, K31, K34, T36, M45, P46, K47, A49, T50, E51, L52, K53, H54, Q56, E59, E66, N70, Q73, S74, K75, N76, 6, F77, H78, R80, P81, R82, D83, S86, N87, 188, V90, 191, L93, E94, K96, G97, S98, E99, T100, T101, F102, M103, C104, E105, Y106, A107, D108, D108, E109, T110, A111, T112, E115, N118, R119, T122, F123, S124, Q125, S126, S129, T130, L131, and T132 in the N87R variant. Further described herein is an IL-2 conjugate, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is selected from K8, H15, L18, D19, M22, N25, N87, V90, I91, L93, E94, K96, G97, S98, E99, D108 in the N87R variant, N118, T122, S124, Q125, S126, S129, and T130.Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is selected from K8, H15, L18, D19, M22, N25, N87, V90, E99, D108 in the N87R variant, N118, T122, S124, and T130. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is K8. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII) in the amino acid sequence of the IL-2 conjugate is H15. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is L18. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is D19. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is M22. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII) in the amino acid sequence of the IL-2 conjugate is N25. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is N87. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is V90.Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is E99. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is D108 in the N87R variant. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is N118. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is T122. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is S124. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is T130. Further described herein are IL-2 conjugates, wherein n is about 75 to about 1000. Further described herein are IL-2 conjugates, wherein n is about 100 to about 1000. Further described herein are IL-2 conjugates, wherein n is about 200 to about 5000. Further described herein are IL-2 conjugates, wherein n is about 500 to about 1000. Further described herein are IL-2 conjugates wherein n is from about 400 to about 800.

[0019] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX): [ka] (In the formula: n is an integer ranging from about 2 to about 5000; X is of the structure: [ka] and X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue) In some embodiments, the IL-2 conjugate is a pharmaceutically acceptable salt, solvate, or hydrate thereof. Herein and throughout, embodiments of Formula (VIII) and / or (IX) also include pharmaceutically acceptable salts, solvates, or hydrates thereof. Further described herein is a conjugate of formula (VIII) or (IX), or a mixture of formula (VIII) and (IX), in which the position of the structure of formula (VIII) or (IX) in the amino acid sequence of the IL-2 conjugate is P1, T2, S3, S4, S5, T6, K7, K8, Q10, L11, E14, H15, L17, L18, D19, Q21, M22, N25, G26, N28, N29, Y30, K31, K34, T36, M45, P46, K47, A49, T50, E51, L52, K53, H54, Q56, E59, E66, N70, Q73, S74, K75, N76, 76, F77, H78, R80, P81, R82, D83, S86, N87, 188, V90, 191, L93, E94, K96, G97, S98, E99, T100, T101, F102, M103, C104, E105, Y106, A107, D108, D108, E109, T110, A111, T112, E115, N118, R119, T122, F123, S124, Q125, S126, S129, T130, L131, and T132 in the N87R variant. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is selected from K8, H15, L18, D19, M22, N25, N87, V90, I91, L93, E94, K96, G97, S98, E99, D108 in the N87R variant, N118, T122, S124, Q125, S126, S129, and T130.Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is selected from K8, H15, L18, D19, M22, N25, N87, V90, E99, D108 in the N87R variant, N118, T122, S124, and T130. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is K8. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX) in the amino acid sequence of the IL-2 conjugate is H15. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is L18. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is D19. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is M22. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX) in the amino acid sequence of the IL-2 conjugate is N25. Further described herein is an IL-2 conjugate, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is N87.Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is V90. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is E99. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is D108 in the N87R variant. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is N118. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is T122. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is S124. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is T130. Further described herein are IL-2 conjugates, wherein n is from about 75 to about 1000. Further described herein are IL-2 conjugates, wherein n is from about 100 to about 1000. Further described herein are IL-2 conjugates wherein n is from about 200 to about 5000. Further described herein are IL-2 conjugates wherein n is from about 500 to about 1000. Further described herein are IL-2 conjugates wherein n is from about 400 to about 800.

[0020] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (X) or (XI), or a mixture of (X) and (XI): [ka] (In the formula: n is an integer ranging from about 2 to about 5000; The wavy line indicates a covalent bond to an amino acid residue in SEQ ID NO: 3 that is not replaced. Herein and throughout, embodiments of formula (X) and / or (XI) also include pharmaceutically acceptable salts, solvates, or hydrates thereof. Further described herein is a conjugate of formula (X) or (XI), or a mixture of formula (X) and formula (XI), wherein the position of the structure of formula (X) or (XI), or a mixture of formula (X) and formula (XI), in the amino acid sequence of the conjugate is selected from the group consisting of P1, T2, S3, S4, S5, T6, K7, K8, Q10, L11, E14, H15, L17, L18, D19, Q21, M22, N25, G26, N28, N29, Y30, K31, K34, T36, M45, P46, K47, A49, T50, E51, L52, K53, H54, Q56, E59, E66, N70, Q73, S74, K75, N76, and wherein the IL-2 conjugate is selected from F77, H78, R80, P81, R82, D83, S86, N87, 188, V90, 191, L93, E94, K96, G97, S98, E99, T100, T101, F102, M103, C104, E105, Y106, A107, D108, D108, E109, T110, A111, T112, E115, N118, R119, T122, F123, S124, Q125, S126, S129, T130, L131, and T132 in the N87R variant. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is selected from K8, H15, L18, D19, M22, N25, N87, V90, I91, L93, E94, K96, G97, S98, E99, D108 in the N87R variant, N118, T122, S124, Q125, S126, S129, and T130. Further described herein is an IL-2 conjugate, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is selected from K8, H15, L18, D19, M22, N25, N87, V90, E99, D108 in the N87R variant, N118, T122, S124, and T130.Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is K8. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is H15. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is L18. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is D19. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is M22. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is N25. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is N87. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is V90. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is E99. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is D108 in the N87R variant.Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is N118. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is T122. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is S124. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is T130. Further described herein are IL-2 conjugates wherein n is about 75 to about 1000. Further described herein are IL-2 conjugates wherein n is about 100 to about 1000. Further described herein are IL-2 conjugates wherein n is about 200 to about 5000. Further described herein are IL-2 conjugates wherein n is about 500 to about 1000. Further described herein are IL-2 conjugates wherein n is about 400 to about 800.

[0021] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII): [ka] (In the formula: n is an integer ranging from about 2 to about 5000; The wavy line indicates a covalent bond to an amino acid residue in SEQ ID NO: 3 that is not replaced. Herein and throughout, embodiments of formula (XII) and / or (XIII) also include pharmaceutically acceptable salts, solvates, or hydrates thereof. Further described herein is a conjugate of formula (XII) or (XIII), or a mixture of formula (XII) and (XIII), in which the position of the structure of formula (XII) or (XIII), or a mixture of formula (XII) and (XIII), in the amino acid sequence of the conjugate is P1, T2, S3, S4, S5, T6, K7, K8, Q10, L11, E14, H15, L17, L18, D19, Q21, M22, N25, G26, N28, N29, Y30, K31, K34, T36, M45, P46, K47, A49, T50, E51, L52, K53, H54, Q56, E59, E66, N70, Q73, S74, K75, N76, F77, H78, R80, P81, R82, D83, S86, N87, I88, V90, I91, L93, E94, K96, G97, S98, E99, T100, T101, F102, M103, C104, E105, Y106, A107, D108, D108, E109, T110, A111, T112, E115, N118, R119, T122, F123, S124, Q125, S126, S129, T130, L131, and T132 in the N87R variant. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is selected from K8, H15, L18, D19, M22, N25, N87, V90, I91, L93, E94, K96, G97, S98, E99, D108 in the N87R variant, N118, T122, S124, Q125, S126, S129, and T130. Further described herein is an IL-2 conjugate, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is selected from K8, H15, L18, D19, M22, N25, N87, V90, E99, D108 in the N87R variant, N118, T122, S124, and T130.Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is K8. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is H15. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is L18. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is D19. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is M22. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is N25. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is N87. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is V90. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is E99.Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is D108 in the N87R variant. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is N118. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is T122. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is S124. Further described herein are IL-2 conjugates wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is T130. Further described herein are IL-2 conjugates wherein n is about 75 to about 1000. Further described herein are IL-2 conjugates wherein n is about 100 to about 1000. Further described herein are IL-2 conjugates wherein n is about 200 to about 5000. Further described herein are IL-2 conjugates wherein n is about 500 to about 1370. Further described herein are IL-2 conjugates wherein n is about 400 to about 800. Further described herein are IL-2 conjugates wherein n is about 400 to about 1370. Further described herein are IL-2 conjugates wherein n is from about 400 to about 1250. Further described herein are IL-2 conjugates wherein n is from about 600 to about 1370. Further described herein are IL-2 conjugates wherein n is from about 600 to about 1250.Further described herein are IL-2 conjugates wherein n is about 675 to about 1250. Further described herein are IL-2 conjugates wherein n is about 680 to about 1250. Further described herein are IL-2 conjugates wherein n is about 680 to about 1140. Further described herein are IL-2 conjugates wherein n is about 450. Further described herein are IL-2 conjugates wherein n is about 568. Further described herein are IL-2 conjugates wherein n is about 682. Further described herein are IL-2 conjugates wherein n is about 795. Further described herein are IL-2 conjugates wherein n is about 909. Further described herein are IL-2 conjugates wherein n is about 1022. Further described herein are IL-2 conjugates wherein n is about 1136. Further described herein are IL-2 conjugates wherein n is about 1250. Further described herein are IL-2 conjugates wherein n is about 1363.

[0022] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 4, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (VI) or (VII), or a mixture of (VI) and (VII): [ka] (In the formula: n is an integer ranging from about 2 to about 5000; X is of the structure: [ka] and X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue) In some embodiments, the IL-2 conjugate is a pharmaceutically acceptable salt, solvate, or hydrate thereof. Further described herein is an IL-2 conjugate wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is replaced by A1, P2, T3, S4, S5, S6, T7, K8, K9, Q11, L12, E15, H16, L18, L19, D20, Q22, M23, N26, G27, N29, N30, Y31, K32, K35, T37, M46, P47, K48, A50, T51, E52, L53, H55, Q57, E60, E67, N71, Q74, S75, K76, N77, F78, H79, R81, P82, R83, D84, S87, N88, I89, V91, I92, L94, E95, K97, G98, S99, E100, T101, T102, F103, M104, C105, E106, Y107, A108, D109, D109 in the N88R variant, E110, T111, A112, T113, E116, N119, R120, T123, S125, Q126, S127, S130, T131, L132, and T133. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is selected from K9, H16, L19, D20, M23, N26, N88, V91, I92, L94, E95, K97, G98, S99, E100, D109 in the N88R variant, N119, T123, S125, Q126, S127, S130, and T131. Further described herein is an IL-2 conjugate, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is selected from K9, H16, L19, D20, M23, N26, N88, V91, E100, D109 in the N88R variant, N119, T123, S125, and T131.Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is K9. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is H16. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is L19. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII) in the amino acid sequence of the IL-2 conjugate is D20. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is M23. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is N26. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is N88. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is V91. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is E100.Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is D109 in the N88R variant. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is N119. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is T123. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is S125. Further described herein are IL-2 conjugates wherein the position of the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), in the amino acid sequence of the IL-2 conjugate is T131. Further described herein are IL-2 conjugates wherein n is about 75 to about 1000. Further described herein are IL-2 conjugates wherein n is about 100 to about 1000. Further described herein are IL-2 conjugates wherein n is about 200 to about 5000. Further described herein are IL-2 conjugates wherein n is about 500 to about 1370. Further described herein are IL-2 conjugates wherein n is about 400 to about 800. Further described herein are IL-2 conjugates wherein n is about 400 to about 1370. Further described herein are IL-2 conjugates wherein n is from about 400 to about 1250. Further described herein are IL-2 conjugates wherein n is from about 600 to about 1370. Further described herein are IL-2 conjugates wherein n is from about 600 to about 1250.Further described herein are IL-2 conjugates wherein n is about 675 to about 1250. Further described herein are IL-2 conjugates wherein n is about 680 to about 1250. Further described herein are IL-2 conjugates wherein n is about 680 to about 1140. Further described herein are IL-2 conjugates wherein n is about 450. Further described herein are IL-2 conjugates wherein n is about 568. Further described herein are IL-2 conjugates wherein n is about 682. Further described herein are IL-2 conjugates wherein n is about 795. Further described herein are IL-2 conjugates wherein n is about 909. Further described herein are IL-2 conjugates wherein n is about 1022. Further described herein are IL-2 conjugates wherein n is about 1136. Further described herein are IL-2 conjugates wherein n is about 1250. Further described herein are IL-2 conjugates wherein n is about 1363.

[0023] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 4, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX): [ka] (In the formula: n is an integer ranging from about 2 to about 5000; X is of the structure: [ka] and X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue) In some embodiments, the IL-2 conjugate is a pharmaceutically acceptable salt, solvate, or hydrate thereof. Further described herein is an IL-2 conjugate in which the positions of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate are replaced by A1, P2, T3, S4, S5, S6, T7, K8, K9, Q11, L12, E15, H16, L18, L19, D20, Q22, M23, N26, G27, N29, N30, Y31, K32, K35, T37, M46, P47, K48, A50, T51, E52, L53, H55, Q57, E60, E67, N71, Q74, S75, K76 , N77, F78, H79, R81, P82, R83, D84, S87, N88, I89, V91, I92, L94, E95, K97, G98, S99, E100, T101, T102, F103, M104, C105, E106, Y107, A108, D109, D109 in the N88R variant, E110, T111, A112, T113, E116, N119, R120, T123, S125, Q126, S127, S130, T131, L132, and T133. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is selected from K9, H16, L19, D20, M23, N26, N88, V91, I92, L94, E95, K97, G98, S99, E100, D109 in the N88R variant, N119, T123, S125, Q126, S127, S130, and T131. Further described herein is an IL-2 conjugate, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is selected from K9, H16, L19, D20, M23, N26, N88, V91, E100, D109 in the N88R variant, N119, T123, S125, and T131.Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is K9. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is H16. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is L19. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX) in the amino acid sequence of the IL-2 conjugate is D20. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is M23. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is N26. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is N88. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX) in the amino acid sequence of the IL-2 conjugate is V91. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is E100.Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is D109 in the N88R variant. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is N119. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is T123. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is S125. Further described herein are IL-2 conjugates wherein the position of the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), in the amino acid sequence of the IL-2 conjugate is T131. Further described herein are IL-2 conjugates wherein n is about 75 to about 1000. Further described herein are IL-2 conjugates wherein n is about 100 to about 1000. Further described herein are IL-2 conjugates wherein n is about 200 to about 5000. Further described herein are IL-2 conjugates wherein n is about 500 to about 1370. Further described herein are IL-2 conjugates wherein n is about 400 to about 800. Further described herein are IL-2 conjugates wherein n is about 400 to about 1370. Further described herein are IL-2 conjugates wherein n is from about 400 to about 1250. Further described herein are IL-2 conjugates wherein n is from about 600 to about 1370. Further described herein are IL-2 conjugates wherein n is from about 600 to about 1250.Further described herein are IL-2 conjugates wherein n is about 675 to about 1250. Further described herein are IL-2 conjugates wherein n is about 680 to about 1250. Further described herein are IL-2 conjugates wherein n is about 680 to about 1140. Further described herein are IL-2 conjugates wherein n is about 450. Further described herein are IL-2 conjugates wherein n is about 568. Further described herein are IL-2 conjugates wherein n is about 682. Further described herein are IL-2 conjugates wherein n is about 795. Further described herein are IL-2 conjugates wherein n is about 909. Further described herein are IL-2 conjugates wherein n is about 1022. Further described herein are IL-2 conjugates wherein n is about 1136. Further described herein are IL-2 conjugates wherein n is about 1250. Further described herein are IL-2 conjugates wherein n is about 1363.

[0024] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 4, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (X) or (XI), or a mixture of (X) and (XI): [ka] (In the formula: n is an integer ranging from about 2 to about 5000; The wavy line indicates a covalent bond to an amino acid residue in SEQ ID NO: 4 that is not replaced. Further described herein is an IL-2 conjugate, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is replaced by A1, P2, T3, S4, S5, S6, T7, K8, K9, Q11, L12, E15, H16, L18, L19, D20, Q22, M23, N26, G27, N29, N30, Y31, K32, K35, T37, M46, P47, K48, A50, T51, E52, L53, H55, Q57, E60, E67, N71, Q74, S75, K76, N77, 7, F78, H79, R81, P82, R83, D84, S87, N88, 189, V91, 192, L94, E95, K97, G98, S99, E100, T101, T102, F103, M104, C105, E106, Y107, A108, D109, D109 in the N88R variant, E110, T111, A112, T113, E116, N119, R120, T123, S125, Q126, S127, S130, T131, L132, and T133. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is selected from K9, H16, L19, D20, M23, N26, N88, V91, I92, L94, E95, K97, G98, S99, E100, D109 in the N88R variant, N119, T123, S125, Q126, S127, S130, and T131. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is selected from K9, H16, L19, D20, M23, N26, N88, V91, E100, D109 in the N88R variant, N119, T123, S125, and T131. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is K9.Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is H16. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is L19. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is D20. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI) in the amino acid sequence of the IL-2 conjugate is M23. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is N26. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is N88. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is V91. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is E100. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is D109 in the N88R variant. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is N119.Further described herein are IL-2 conjugates wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is T123. Further described herein are IL-2 conjugates wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is S125. Further described herein are IL-2 conjugates wherein the position of the structure of formula (X) or (XI), or a mixture of (X) and (XI), in the amino acid sequence of the IL-2 conjugate is T131. Further described herein are IL-2 conjugates wherein n is from about 75 to about 1000. Further described herein are IL-2 conjugates wherein n is from about 100 to about 1000. Further described herein are IL-2 conjugates wherein n is about 200 to about 5000. Further described herein are IL-2 conjugates wherein n is about 500 to about 1370. Further described herein are IL-2 conjugates wherein n is about 400 to about 800. Further described herein are IL-2 conjugates wherein n is about 400 to about 1370. Further described herein are IL-2 conjugates wherein n is about 400 to about 1250. Further described herein are IL-2 conjugates wherein n is about 600 to about 1370. Further described herein are IL-2 conjugates wherein n is about 600 to about 1250. Further described herein are IL-2 conjugates wherein n is about 675 to about 1250. Further described herein are IL-2 conjugates wherein n is about 680 to about 1250. Further described herein are IL-2 conjugates wherein n is about 680 to about 1140. Further described herein are IL-2 conjugates wherein n is about 450. Further described herein are IL-2 conjugates wherein n is about 568. Further described herein are IL-2 conjugates wherein n is about 682.Further described herein is an IL-2 conjugate wherein n is about 795. Further described herein is an IL-2 conjugate wherein n is about 909. Further described herein is an IL-2 conjugate wherein n is about 1022. Further described herein is an IL-2 conjugate wherein n is about 1136. Further described herein is an IL-2 conjugate wherein n is about 1022. , is about 1250. Further described herein are IL-2 conjugates wherein n is about 1363.

[0025] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 4, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII): [ka] (In the formula: n is an integer ranging from about 2 to about 5000; The wavy line indicates a covalent bond to an amino acid residue in SEQ ID NO: 4 that is not replaced. Further described herein is an IL-2 conjugate, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is replaced by A1, P2, T3, S4, S5, S6, T7, K8, K9, Q11, L12, E15, H16, L18, L19, D20, Q22, M23, N26, G27, N29, N30, Y31, K32, K35, T37, M46, P47, K48, A50, T51, E52, L53, H55, Q57, E60, E67, N71, Q74, S75, K7 6, N77, F78, H79, R81, P82, R83, D84, S87, N88, 189, V91, 192, L94, E95, K97, G98, S99, E100, T101, T102, F103, M104, C105, E106, Y107, A108, D109, D109 in the N88R variant, E110, T111, A112, T113, E116, N119, R120, T123, S125, Q126, S127, S130, T131, L132, and T133. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is selected from K9, H16, L19, D20, M23, N26, N88, V91, I92, L94, E95, K97, G98, S99, E100, D109 in the N88R variant, N119, T123, S125, Q126, S127, S130, and T131. Further described herein is an IL-2 conjugate, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is selected from K9, H16, L19, D20, M23, N26, N88, V91, E100, D109 in the N88R variant, N119, T123, S125, and T131.Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is K9. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is H16. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is L19. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is D20. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is M23. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is N26. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is N88. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is V91. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is E100.Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is D109 in the N88R variant. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is N119. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is T123. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is S125. Further described herein are IL-2 conjugates wherein the position of the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), in the amino acid sequence of the IL-2 conjugate is T131. Further described herein are IL-2 conjugates wherein n is about 75 to about 1000. Further described herein are IL-2 conjugates wherein n is about 100 to about 1000. Further described herein are IL-2 conjugates wherein n is about 200 to about 5000. Further described herein are IL-2 conjugates wherein n is about 500 to about 1370. Further described herein are IL-2 conjugates wherein n is about 400 to about 800. Further described herein are IL-2 conjugates wherein n is about 400 to about 1370. Further described herein are IL-2 conjugates wherein n is from about 400 to about 1250. Further described herein are IL-2 conjugates wherein n is from about 600 to about 1370. Further described herein are IL-2 conjugates wherein n is from about 600 to about 1250.Further described herein are IL-2 conjugates wherein n is about 675 to about 1250. Further described herein are IL-2 conjugates wherein n is about 680 to about 1250. Further described herein are IL-2 conjugates wherein n is about 680 to about 1140. Further described herein are IL-2 conjugates wherein n is about 450. Further described herein are IL-2 conjugates wherein n is about 568. Further described herein are IL-2 conjugates wherein n is about 682. Further described herein are IL-2 conjugates wherein n is about 795. Further described herein are IL-2 conjugates wherein n is about 909. Further described herein are IL-2 conjugates wherein n is about 1022. Further described herein are IL-2 conjugates wherein n is about 1136. Further described herein are IL-2 conjugates wherein n is about 1250. Further described herein are IL-2 conjugates wherein n is about 1363.

[0026] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3 or SEQ ID NO:4, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV): [ka] (In the formula: m is an integer from 0 to 20; p is an integer from 0 to 20; n is an integer ranging from about 2 to about 5000; The wavy line indicates a covalent bond to an amino acid residue in SEQ ID NO:3 or SEQ ID NO:4 that is not replaced.

[0033] Herein and throughout, embodiments of Formula (XIV) and / or (XV) also encompass pharmaceutically acceptable salts, solvates, or hydrates thereof. In some embodiments described herein, an IL-2 conjugate comprises the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced by a structure of Formula (XIV) or (XV), or a mixture of (XIV) and (XV), wherein m, p, n, and the wavy line are defined above. In some embodiments described herein, an IL-2 conjugate comprises the amino acid sequence of SEQ ID NO: 4, wherein at least one amino acid residue in the IL-2 conjugate is replaced by a structure of Formula (XIV) or (XV), or a mixture of (XIV) and (XV), wherein m, p, n, and the wavy line are defined above.

[0027] In some embodiments, the stereochemistry of the chiral centers in Formula (XIV) and Formula (XV) is racemic, (R)-rich, (S)-rich, substantially (R), substantially (S), (R), or (S). In some embodiments, the stereochemistry of the chiral centers in Formula (XIV) and Formula (XV) is racemic. In some embodiments, the stereochemistry of the chiral centers in Formula (XIV) and Formula (XV) is (R)-rich. In some embodiments, the stereochemistry of the chiral centers in Formula (XIV) and Formula (XV) is (S)-rich. In some embodiments, the stereochemistry of the chiral centers in Formula (XIV) and Formula (XV) is substantially (R). In some embodiments, the stereochemistry of the chiral centers in Formula (XIV) and Formula (XV) is substantially (S). In some embodiments, the stereochemistry of the chiral centers in Formula (XIV) and Formula (XV) is (R). In some embodiments, the stereochemistry of the chiral centers in Formula (XIV) and Formula (XV) is (S).

[0028] In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XIV) and (XV) is 0 to 20, or 1 to 18, or 1 to 16, or 1 to 14, or 1 to 12, or 1 to 10, or 1 to 9, or 1 to 8, or 1 to 7, or 1 to 6, or 1 to 5, or 1 to 4, or 1 to 3, or 1 to 2. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XIV) and (XV) is 1. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XIV) and (XV) is 2. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XIV) and (XV) is 3. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XIV) and (XV) is 4. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XIV) and (XV) is 5. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XIV) and (XV) is 6. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XIV) and (XV) is 7. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XIV) and (XV) is 8. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XIV) and (XV) is 9. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XIV) and (XV) is 10. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XIV) and (XV) is 11. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formula (XIV) and (XV) is 12. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formula (XIV) and (XV) is 13.In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XIV) and (XV) is 14. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XIV) and (XV) is 15. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XIV) and (XV) is 16. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XIV) and (XV) is 17. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XIV) and (XV) is 18. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XIV) and (XV) is 19. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XIV) and (XV) is 20.

[0029] In some embodiments of the IL-2 conjugates described herein, p in the compounds of Formula (XIV) and (XV) is 1 to 20, or 1 to 18, or 1 to 16, or 1 to 14, or 1 to 12, or 1 to 10, or 1 to 9, or 1 to 8, or 1 to 7, or 1 to 6, or 1 to 5, or 1 to 4, or 1 to 3, or 1 to 2. In some embodiments of the IL-2 conjugates described herein, p in the compounds of Formula (XIV) and (XV) is 1. In some embodiments of the IL-2 conjugates described herein, p in the compounds of Formula (XIV) and (XV) is 2. In some embodiments of the IL-2 conjugates described herein, p in the compounds of Formula (XIV) and (XV) is 3. In some embodiments of the IL-2 conjugates described herein, p in the compounds of Formula (XIV) and (XV) is 4. In some embodiments of the IL-2 conjugates described herein, p in the compounds of Formula (XIV) and (XV) is 5. In some embodiments of the IL-2 conjugates described herein, p in the compounds of Formula (XIV) and (XV) is 6. In some embodiments of the IL-2 conjugates described herein, p in the compounds of Formula (XIV) and (XV) is 7. In some embodiments of the IL-2 conjugates described herein, p in the compounds of Formula (XIV) and (XV) is 8. In some embodiments of the IL-2 conjugates described herein, p in the compounds of Formula (XIV) and (XV) is 9. In some embodiments of the IL-2 conjugates described herein, p in the compounds of Formula (XIV) and (XV) is 10. In some embodiments of the IL-2 conjugates described herein, p in the compounds of Formula (XIV) and (XV) is 11. In some embodiments of the IL-2 conjugates described herein, p in the compounds of formula (XIV) and (XV) is 12. In some embodiments of the IL-2 conjugates described herein, p in the compounds of formula (XIV) and (XV) is 13.In some embodiments of the IL-2 conjugates described herein, p in the compounds of Formula (XIV) and (XV) is 14. In some embodiments of the IL-2 conjugates described herein, p in the compounds of Formula (XIV) and (XV) is 15. In some embodiments of the IL-2 conjugates described herein, p in the compounds of Formula (XIV) and (XV) is 16. In some embodiments of the IL-2 conjugates described herein, p in the compounds of Formula (XIV) and (XV) is 17. In some embodiments of the IL-2 conjugates described herein, p in the compounds of Formula (XIV) and (XV) is 18. In some embodiments of the IL-2 conjugates described herein, p in the compounds of Formula (XIV) and (XV) is 19. In some embodiments of the IL-2 conjugates described herein, p in the compounds of Formula (XIV) and (XV) is 20.

[0030] In some embodiments of the IL-2 conjugates described herein, n in compounds of formula (XIV) and (XV) is from about 5 to about 4600, or from about 10 to about 4000, or from about 20 to about 3000, or from about 100 to about 3000, or from about 100 to about 2900, or from about 150 to about 2900, or from about 125 to about 2900, or from about 100 to about 2500, or from about 100 to about 2000, or from about 100 to about 1900, or from about 100 to about 1850, or from about 100 to about 1750. , or about 100 to about 1650, or about 100 to about 1500, or about 100 to about 1400, or about 100 to about 1300, or about 100 to about 1250, or about 100 to about 1150, or about 100 to about 1100, or about 100 to about 1000, or about 100 to about 900, or about 100 to about 750, or about 100 to about 700, or about 100 to about 600, or about 100 to about 575, or about 100 to about 500, or about 100 to about 450, or about 100 to about 350, or about 100 to about 275, or about 100 to about 230, or about 150 to about 475, or about 150 to about 340, or about 113 to about 340, or about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 340 to about 795, or about 341 to about 682, or about 568 to about 909, or about 227 to about 1500, or about 225 to about 2280, or about 460 to about 2160, or about 460 to about 2050, or about 341 to about 1820, or about The molecular weight range is from 341 to about 1710, or from about 341 to about 1250, or from about 225 to about 1250, or from about 341 to about 1250, or from about 341 to about 1136, or from about 341 to about 1023, or from about 341 to about 910, or from about 341 to about 796, or from about 341 to about 682, or from about 341 to about 568, or from about 114 to about 1000, or from about 114 to about 950, or from about 114 to about 910, or from about 114 to about 800, or from about 114 to about 690, or from about 114 to about 575.

[0031] In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XIV) and (XV), m is an integer from 1 to 6, p is an integer from 1 to 6, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XIV) and (XV), m is an integer from 2 to 6, p is an integer from 2 to 6, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XIV) and (XV), m is an integer from 2 to 4, p is an integer from 2 to 4, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XIV) and (XV), m is 1, p is 2, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XIV) and (XV), m is 2, p is 2, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137.In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XIV) and (XV), m is 3, p is 2, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XIV) and (XV), m is 4, p is 2, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XIV) and (XV), m is 5, p is 2, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XIV) and (XV), m is 6, p is 2, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XIV) and (XV), m is 7, p is 2, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137.In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XIV) and (XV), m is 8, p is 2, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XIV) and (XV), m is 9, p is 2, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XIV) and (XV), m is 10, p is 2, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XIV) and (XV), m is 11, p is 2, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XIV) and (XV), m is 12, p is 2, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137.In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XIV) and (XV), m is 2, p is 2, and n is an integer selected from 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137.

[0032] In some embodiments of the IL-2 conjugates described herein, n in the compounds of formula (XIV) and (XV) is 2, 5, 10, 11, 22, 23, 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, 1249, 1250, 1251, 1362, 1363, 1364, 1 is an integer selected from 476, 1477, 1478, 1589, 1590, 1591, 1703, 1704, 1705, 1817, 1818, 1819, 1930, 1931, 1932, 2044, 2045, 2046, 2158, 2159, 2160, 2271, 2272, 2273, 2839, 2840, 2841, 2953, 2954, 2955, 3408, 3409, 3410, 3976, 3977, 3978, 4544, 4545, and 4546.

[0033] In some embodiments of the IL-2 conjugates described herein, when the IL-2 conjugate comprises SEQ ID NO: 3, the positions of the structures of formula (XIV) and (XV) or a mixture of formula (XIV) and (XV) in the amino acid sequence of the IL-2 conjugate are P1, T2, S3, S4, S5, T6, K7, K8, Q10, L11, E14, H15, L17, L18, D19, Q21, M22, N25, G26, N28, N29, Y30, K31, K34, T36, M45, P46, K47, A49, T50, E51, L52, K53, H54, Q56 , E59, E66, N70, Q73, S74, K75, N76, F77, H78, R80, P81, R82, D83, S86, N87, I88, V90, I91, L93, E94, K96, G97, S98, E99, T100, T101, F102, M103, C104, E105, Y106, A107, D108, D108, E109, T110, A111, T112, E115, N118, R119, T122, F123, S124, Q125, S126, S129, T130, L131, and T132 in the N87R variant. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is selected from K8, H15, L18, D19, M22, N25, N87, V90, I91, L93, E94, K96, G97, S98, E99, D108 in the N87R variant, N118, T122, S124, Q125, S126, S129, and T130. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is selected from K8, H15, L18, D19, M22, N25, N87, V90, E99, D108 in the N87R variant, N118, T122, S124, and T130. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is K8.Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is H15. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is L18. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is D19. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is M22. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is N25. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is N87. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is V90. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is E99. Further described herein is an IL-2 conjugate, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is D108 in the N87R variant.Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is N118. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is T122. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is S124. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is T130. In some embodiments of the IL-2 conjugates described herein, the ratio of the amount of the structure of formula (XIV) to the amount of the structure of formula (XV), including the total amount in the IL-2 conjugate, is about 1:1. In some embodiments of the IL-2 conjugates described herein, the ratio of the amount of the structure of formula (XIV) to the amount of the structure of formula (XV), including the total amount in the IL-2 conjugate, is greater than 1:1. In some embodiments of the IL-2 conjugates described herein, the ratio of the amount of the structure of formula (XIV) to the amount of the structure of formula (XV), including the total amount in the IL-2 conjugate, is less than 1:1.

[0034] In some embodiments of the IL-2 conjugates described herein, when the IL-2 conjugate comprises SEQ ID NO: 4, the positions of the structures of formula (XIV) and (XV) or a mixture of formula (XIV) and (XV) in the amino acid sequence of the IL-2 conjugate are A1, P2, T3, S4, S5, S6, T7, K8, K9, Q11, L12, E15, H16, L18, L19, D20, Q22, M23, N26, G27, N29, N30, Y31, K32, K35, T37, M46, P47, K48, A50, T51, E52, L53, H55, Q5 7, E60, E67, N71, Q74, S75, K76, N77, F78, H79, R81, P82, R83, D84, S87, N88, I89, V91, I92, L94, E95, K97, G98, S99, E100, T101, T102, F103, M104, C105, E106, Y107, A108, D109, D109 in the N88R variant, E110, T111, A112, T113, E116, N119, R120, T123, S125, Q126, S127, S130, T131, L132, and T133. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is selected from K9, H16, L19, D20, M23, N26, N88, V91, I92, L94, E95, K97, G98, S99, E100, D109 in the N88R variant, N119, T123, S125, Q126, S127, S130, and T131. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is selected from K9, H16, L19, D20, M23, N26, N88, V91, E100, D109 in the N88R variant, N119, T123, S125, and T131. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is K9.Further described herein is an IL-2 conjugate, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is H16. Further described herein is an IL-2 conjugate, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is L19. Further described herein is an IL-2 conjugate, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is D20. Further described herein is an IL-2 conjugate, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is M23. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is N26. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is N88. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is V91. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is E100. Further described herein is an IL-2 conjugate, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is D109 in the N88R variant.Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is N119. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is T123. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is S125. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate is T131. In some embodiments of the IL-2 conjugates described herein, the ratio of the amount of the structure of formula (XIV) comprising the total amount in the IL-2 conjugate to the amount of the structure of formula (XV) is about 1:1. In some embodiments of the IL-2 conjugates described herein, the ratio of the amount of the structure of formula (XIV) comprising the total amount in the IL-2 conjugate to the amount of the structure of formula (XV) is greater than 1:1. In some embodiments of the IL-2 conjugates described herein, the ratio of the amount of the structure of formula (XIV) comprising the total amount in the IL-2 conjugate to the amount of the structure of formula (XV) is less than 1:1.

[0035] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with a structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), and the replaced amino acid residues in SEQ ID NO: 3 are K8, H15, L18, D19, M22, N25, N87, V90, E99, D10 in the N87R variant, or any combination thereof. 8, N118, T122, S124, and T130, where n is selected from 100 to about 1150, or from about 100 to about 1100, or from about 100 to about 1000, or from about 100 to about 900, or from about 100 to about 750, or from about 100 to about 700, or from about 100 to about 600, or from about 100 to about 575, or from about 100 to about 500, or from about 100 to about 450, or from about 100 to about 350, or from about 100 to about 275, or from about 100 to about 230, is about 150 to about 475, or about 150 to about 340, or about 113 to about 340, or about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 340 to about 795, or about 341 to about 682, or about 568 to about 909, or about 227 to about 1500, or about 225 to about 2280, or about 460 to about 2160, or about 460 to about 2050, or about 341 to about 1820, or about 341 to about 1710, or about It is an integer from 341 to about 1250, or from about 225 to about 1250, or from about 341 to about 1250, or from about 341 to about 1136, or from about 341 to about 1023, or from about 341 to about 910, or from about 341 to about 796, or from about 341 to about 682, or from about 341 to about 568, or from about 114 to about 1000, or from about 114 to about 950, or from about 114 to about 910, or from about 114 to about 800, or from about 114 to about 690, or from about 114 to about 575.In some embodiments of the IL-2 conjugates described herein, n in the compounds of formula (XIV) and (XV) is 2, 5, 10, 11, 22, 23, 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, 1249, 1250, 1251, 1362, 1363, 1364, 1 and an integer selected from 476, 1477, 1478, 1589, 1590, 1591, 1703, 1704, 1705, 1817, 1818, 1819, 1930, 1931, 1932, 2044, 2045, 2046, 2158, 2159, 2160, 2271, 2272, 2273, 2839, 2840, 2841, 2953, 2954, 2955, 3408, 3409, 3410, 3976, 3977, 3978, 4544, 4545 and 4546.

[0036] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 4, wherein at least one amino acid residue in the IL-2 conjugate is replaced with a structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), and the replaced amino acid residues in SEQ ID NO: 3 are K9, H16, L19, D20, M23, N26, N88, V91, I92, L94, E95, K97, G98, S99, E100, N and n is selected from D109, N119, T123, S125, Q126, S127, S130, and T131 in the 88R variant, and n is 100 to about 1150, or about 100 to about 1100, or about 100 to about 1000, or about 100 to about 900, or about 100 to about 750, or about 100 to about 700, or about 100 to about 600, or about 100 to about 575, or about 100 to about 500, or about 100 to about 450, or about 100 to about 350, or about 100 to about 575. about 275, or about 100 to about 230, or about 150 to about 475, or about 150 to about 340, or about 113 to about 340, or about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 340 to about 795, or about 341 to about 682, or about 568 to about 909, or about 227 to about 1500, or about 225 to about 2280, or about 460 to about 2160, or about 460 to about 2050, or about 341 to about 1820, or about 341 to about It is an integer of about 1710, or about 341 to about 1250, or about 225 to about 1250, or about 341 to about 1250, or about 341 to about 1136, or about 341 to about 1023, or about 341 to about 910, or about 341 to about 796, or about 341 to about 682, or about 341 to about 568, or about 114 to about 1000, or about 114 to about 950, or about 114 to about 910, or about 114 to about 800, or about 114 to about 690, or about 114 to about 575.In some embodiments of the IL-2 conjugates described herein, n in the compounds of formula (XIV) and (XV) is 2, 5, 10, 11, 22, 23, 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, 1249, 1250, 1251, 1362, 1363, 1364, 1 and an integer selected from 476, 1477, 1478, 1589, 1590, 1591, 1703, 1704, 1705, 1817, 1818, 1819, 1930, 1931, 1932, 2044, 2045, 2046, 2158, 2159, 2160, 2271, 2272, 2273, 2839, 2840, 2841, 2953, 2954, 2955, 3408, 3409, 3410, 3976, 3977, 3978, 4544, 4545 and 4546.

[0037] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3 or SEQ ID NO:4, wherein at least one amino acid residue in the IL-2 conjugate is replaced with a structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), and n is the molecular weight of the PEG moiety from about 1,000 daltons to about 200,000 daltons, or from about 2,000 daltons to about 150,000 daltons, or from about 3,000 daltons to about 125,000 daltons, or from about 4,000 daltons to about 100,000 daltons, or from about 5,000 daltons to about 100,000 daltons, or about 6,000 daltons to about 90,000 daltons, or about 7,000 daltons to about 80,000 daltons, or about 8,000 daltons to about 70,000 daltons, or about 5,000 daltons to about 70,000 daltons, or about 5,000 daltons to about 65,000 daltons, or about 5,000 daltons to about 60,000 daltons, or about 5,000 daltons to about 50,000 daltons, or about 6,000 daltons to about 50,000 daltons, or about 7,000 daltons to about 50,000 daltons 00 daltons, or about 7,000 daltons to about 45,000 daltons, or about 7,000 daltons to about 40,000 daltons, or about 8,000 daltons to about 40,000 daltons, or about 8,500 daltons to about 40,000 daltons, or about 8,500 daltons to about 35,000 daltons, or about 9,000 daltons to about 50,000 daltons, or about 9,000 daltons to about 45,000 daltons, or about 9,000 daltons to about 40,000 daltons, or about 9,000 daltons to about 35,000 daltons, or about 9,000 daltons to about 50,000 daltons Daltons to about 30,000 Daltons, or about 9,500 Daltons to about 35,000 Daltons, or about 9,500 Daltons to about 30,000 Daltons, or about 10,000 Daltons to about 50,000 Daltons, or about 10,000 Daltons to about 45,000 Daltons, or about 10,000 Daltons to about 40,000 Daltons, or about 10,000 Daltons to about 35,000 Daltons, or about 10,000 Daltons to about 30,000 Daltons, or about 15,000 Daltons to about 50,000 Daltons, or about 15,000 Daltons to about 45,000 Daltons000 daltons, or about 15,000 daltons to about 40,000 daltons, or about 15,000 daltons to about 35,000 daltons, or about 15,000 daltons to about 30,000 daltons, or about 20,000 daltons to about 50,000 daltons, or about 20,000 daltons to about 45,000 daltons, or about 20,000 daltons to about 40,000 daltons, or about 20,000 daltons to about 35,000 daltons, or about 20,000 daltons to about 30,000 daltons. Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3 or SEQ ID NO:4, wherein at least one amino acid residue in the IL-2 conjugate is replaced with a structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), and n is a molecular weight of the PEG moiety of about 5,000 daltons, about 7,500 daltons, about 10,000 daltons, about 15,000 daltons, about 20,000 daltons, or about 30,000 daltons. , about 25,000 daltons, about 30,000 daltons, about 35,000 daltons, about 40,000 daltons, about 45,000 daltons, about 50,000 daltons, about 60,000 daltons, about 70,000 daltons, about 80,000 daltons, about 90,000 daltons, about 100,000 daltons, about 125,000 daltons, about 150,000 daltons, about 175,000 daltons or about 200,000 daltons. Described herein are IL-2 conjugates comprising the amino acid sequence of SEQ ID NO:3 or SEQ ID NO:4, wherein at least one amino acid residue in the IL-2 conjugate is replaced with a structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), and n is an integer such that the molecular weight of the PEG moiety is about 5,000 daltons, about 7,500 daltons, about 10,000 daltons, about 15,000 daltons, about 20,000 daltons, about 25,000 daltons, about 30,000 daltons, about 35,000 daltons, about 40,000 daltons, about 45,000 daltons, or about 50,000 daltons.

[0038] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with a structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), wherein the replaced amino acid residue in SEQ ID NO: 3 is H15, m is an integer from 1 to 6, p is an integer from 1 to 6, and n is an integer from about 450 to about 800, or from about 454 to about 796, or from about 454 to about 682, or from about 568 to about 909. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XIV) and (XV), m is 2, p is 2, and n is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910.

[0039] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with a structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), wherein the replaced amino acid residue in SEQ ID NO: 3 is H15, m is an integer from 1 to 6, p is an integer from 1 to 6, and n is an integer from about 450 to about 800, or from about 454 to about 796, or from about 454 to about 682, or from about 568 to about 909. In some embodiments of the IL-2 conjugates described herein, in the compounds of Formula (XIV) and (XV), m is 2, p is 2, and n is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910. In some embodiments, n is about 500 to about 1000. In some embodiments, n is about 550 to about 800. In some embodiments, n is about 681.

[0040] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 4, wherein at least one amino acid residue in the IL-2 conjugate is replaced with a structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), wherein the replaced amino acid residue in SEQ ID NO: 4 is H16, m is an integer from 1 to 6, p is an integer from 1 to 6, and n is an integer from about 450 to about 800, or from about 454 to about 796, or from about 454 to about 682, or from about 568 to about 909. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XIV) and (XV), m is 2, p is 2, and n is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910.

[0041] In some embodiments, described herein are IL-2 conjugates comprising the amino acid sequence of SEQ ID NO: 4, wherein at least one amino acid residue in the IL-2 conjugate is replaced with a structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), wherein the replaced amino acid residue in SEQ ID NO: 4 is H16, m is an integer from 1 to 6, p is an integer from 1 to 6, and n is an integer from about 450 to about 800, or from about 454 to about 796, or from about 454 to about 682, or from about 568 to about 909. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XIV) and (XV), m is 2, p is 2, and n is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910. In some embodiments, n is from about 500 to about 1000. In some embodiments, n is from about 550 to about 800. In some embodiments, n is about 681.

[0042] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3 or SEQ ID NO:4, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII): [ka] (In the formula: m is an integer from 0 to 20; n is an integer ranging from about 2 to about 5000; The wavy line indicates a covalent bond to an amino acid residue in SEQ ID NO:3 or SEQ ID NO:4 that is not replaced.

[0033] Herein and throughout, embodiments of Formula (XVI) and / or (XVII) also encompass pharmaceutically acceptable salts, solvates, or hydrates thereof. In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced by the structure of Formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), wherein the meanings of m, p, n, and the dashed line are as described above. In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 4, wherein at least one amino acid residue in the IL-2 conjugate is replaced by the structure of Formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), wherein the meanings of m, p, n, and the dashed line are as described above.

[0043] In some embodiments, the stereochemistry of the chiral centers in Formula (XVI) and Formula (XVII) is racemic, (R)-rich, (S)-rich, substantially (R), substantially (S), (R), or (S). In some embodiments, the stereochemistry of the chiral centers in Formula (XVI) and Formula (XVII) is racemic. In some embodiments, the stereochemistry of the chiral centers in Formula (XVI) and Formula (XVII) is (R)-rich. In some embodiments, the stereochemistry of the chiral centers in Formula (XVI) and Formula (XVII) is (S)-rich. In some embodiments, the stereochemistry of the chiral centers in Formula (XVI) and Formula (XVII) is substantially (R). In some embodiments, the stereochemistry of the chiral centers in Formula (XVI) and Formula (XVII) is substantially (S). In some embodiments, the stereochemistry of the chiral centers in Formula (XVI) and Formula (XVII) is (R). In some embodiments, the stereochemistry of the chiral centers in Formula (XVI) and Formula (XVII) is (S).

[0044] In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XVI) and (XVII) is 1 to 20, or 1 to 18, or 1 to 16, or 1 to 14, or 1 to 12, or 1 to 10, or 1 to 9, or 1 to 8, or 1 to 7, or 1 to 6, or 1 to 5, or 1 to 4, or 1 to 3, or 1 to 2. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XVI) and (XVII) is 1. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XVI) and (XVII) is 2. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XVI) and (XVII) is 3. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XVI) and (XVII) is 4. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XVI) and (XVII) is 5. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XVI) and (XVII) is 6. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XVI) and (XVII) is 7. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XVI) and (XVII) is 8. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XVI) and (XVII) is 9. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XVI) and (XVII) is 10. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XVI) and (XVII) is 11. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formula (XVI) and (XVII) is 12. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formula (XVI) and (XVII) is 13.In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XVI) and (XVII) is 14. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XVI) and (XVII) is 15. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XVI) and (XVII) is 16. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XVI) and (XVII) is 17. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XVI) and (XVII) is 18. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XVI) and (XVII) is 19. In some embodiments of the IL-2 conjugates described herein, m in the compounds of Formula (XVI) and (XVII) is 20.

[0045] In some embodiments of the IL-2 conjugates described herein, n in compounds of formula (XVI) and (XVII) is from about 5 to about 4600, or from about 10 to about 4000, or from about 20 to about 3000, or from about 100 to about 3000, or from about 100 to about 2900, or from about 150 to about 2900, or from about 125 to about 2900, or from about 100 to about 2500, or from about 100 to about 2000, or from about 100 to about 1900, or from about 100 to about 1850, or from about 100 to about 175 0, or about 100 to about 1650, or about 100 to about 1500, or about 100 to about 1400, or about 100 to about 1300, or about 100 to about 1250, or about 100 to about 1150, or about 100 to about 1100, or about 100 to about 1000, or about 100 to about 900, or about 100 to about 750, or about 100 to about 700, or about 100 to about 600, or about 100 to about 575, or about 100 to about 500, or about 100 to about 450, or about 100 to about 350 , or about 100 to about 275, or about 100 to about 230, or about 150 to about 475, or about 150 to about 340, or about 113 to about 340, or about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 340 to about 795, or about 341 to about 682, or about 568 to about 909, or about 227 to about 1500, or about 225 to about 2280, or about 460 to about 2160, or about 460 to about 2050, or about 341 to about 1820, or It is in the range of about 341 to about 1710, or about 341 to about 1250, or about 225 to about 1250, or about 341 to about 1250, or about 341 to about 1136, or about 341 to about 1023, or about 341 to about 910, or about 341 to about 796, or about 341 to about 682, or about 341 to about 568, or about 114 to about 1000, or about 114 to about 950, or about 114 to about 910, or about 114 to about 800, or about 114 to about 690, or about 114 to about 575.

[0046] In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XVI) and (XVII), m is an integer from 1 to 6 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XVI) and (XVII), m is an integer from 2 to 6 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XVI) and (XVII), m is an integer from 2 to 4 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XVI) and (XVII), m is 1 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XVI) and (XVII), m is 2 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137.In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XVI) and (XVII), m is 3 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XVI) and (XVII), m is 4 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XVI) and (XVII), m is 5 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XVI) and (XVII), m is 6 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XVI) and (XVII), m is 7 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137.In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XVI) and (XVII), m is 8 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XVI) and (XVII), m is 9 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XVI) and (XVII), m is 10 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XVI) and (XVII), m is 11 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XVI) and (XVII), m is 12 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137.In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XVI) and (XVII), m is 2 and n is an integer selected from 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137.

[0047] In some embodiments of the IL-2 conjugates described herein, n in the compounds of formula (XVI) and (XVII) is 2, 5, 10, 11, 22, 23, 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, 1249, 1250, 1251, 1362, 1363, 1364, is an integer selected from 1476, 1477, 1478, 1589, 1590, 1591, 1703, 1704, 1705, 1817, 1818, 1819, 1930, 1931, 1932, 2044, 2045, 2046, 2158, 2159, 2160, 2271, 2272, 2273, 2839, 2840, 2841, 2953, 2954, 2955, 3408, 3409, 3410, 3976, 3977, 3978, 4544, 4545, and 4546.

[0048] In some embodiments of the IL-2 conjugates described herein, the positions of the structures of formula (XVI) and (XVII) or a mixture of formula (XVI) and (XVII) in the amino acid sequence of the IL-2 conjugate comprising SEQ ID NO: 3 are P1, T2, S3, S4, S5, T6, K7, K8, Q10, L11, E14, H15, L17, L18, D19, Q21, M22, N25, G26, N28, N29, Y30, K31, K34, T36, M45, P46, K47, A49, T50, E51, L52, K53, H54, Q56, E59, E 66, N70, Q73, S74, K75, N76, F77, H78, R80, P81, R82, D83, S86, N87, I88, V90, I91, L93, E94, K96, G97, S98, E99, T100, T101, F102, M103, C104, E105, Y106, A107, D108, D108 in the N87R variant, E109, T110, A111, T112, E115, N118, R119, T122, F123, S124, Q125, S126, S129, T130, L131, and ST132. In some embodiments of the IL-2 conjugates described herein, the positions of the structures of formula (XVI) and (XVII) or a mixture of formula (XVI) and (XVII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 are selected from K8, H15, L18, D19, M22, N25, N87, V90, I91, L93, E94, K96, G97, S98, E99, D108 in the N87R variant, N118, T122, S124, Q125, S126, S129, and T130. Further described herein is an IL-2 conjugate, wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is selected from K8, H15, L18, D19, M22, N25, N87, V90, E99, D108 in the N87R variant, N118, T122, S124, and T130.Further described herein are IL-2 conjugates wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is K8. Further described herein are IL-2 conjugates wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is H15. Further described herein are IL-2 conjugates wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is L18. Further described herein are IL-2 conjugates wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is D19. Further described herein are IL-2 conjugates in which the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is M22. Further described herein are IL-2 conjugates in which the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is N25. Further described herein are IL-2 conjugates in which the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is N87. Further described herein are IL-2 conjugates in which the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII) in the amino acid sequence of the IL-2 conjugate is V90. Further described herein is an IL-2 conjugate, wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is E99.Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is D108 in the N87R variant. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is N118. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII) in the amino acid sequence of the IL-2 conjugate is T122. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is S124. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is T130. In some embodiments of the IL-2 conjugates described herein, the ratio of the amount of the structure of formula (XVI), comprising the total amount in the IL-2 conjugate, to the amount of the structure of formula (XVII) is about 1:1. In some embodiments of the IL-2 conjugates described herein, the ratio of the amount of the structure of formula (XVI), comprising the total amount in the IL-2 conjugate, to the amount of the structure of formula (XVII) is greater than 1:1. In some embodiments of the IL-2 conjugates described herein, the ratio of the amount of the structure of formula (XVI) to the amount of the structure of formula (XVII), including the total amount, in the IL-2 conjugate is less than 1:1.

[0049] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with a structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), and the replaced amino acid residue in SEQ ID NO: 3 is selected from the group consisting of K8, H15, L18, D19, M22, N25, N87, V90, E99, N87R variants. D108, N118, T122, S124, and T130, where n is selected from 100 to about 1150, or from about 100 to about 1100, or from about 100 to about 1000, or from about 100 to about 900, or from about 100 to about 750, or from about 100 to about 700, or from about 100 to about 600, or from about 100 to about 575, or from about 100 to about 500, or from about 100 to about 450, or from about 100 to about 350, or from about 100 to about 275, or from about 100 to about 230. or about 150 to about 475, or about 150 to about 340, or about 113 to about 340, or about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 340 to about 795, or about 341 to about 682, or about 568 to about 909, or about 227 to about 1500, or about 225 to about 2280, or about 460 to about 2160, or about 460 to about 2050, or about 341 to about 1820, or about 341 to about 1710, or is an integer from about 341 to about 1250, or from about 225 to about 1250, or from about 341 to about 1250, or from about 341 to about 1136, or from about 341 to about 1023, or from about 341 to about 910, or from about 341 to about 796, or from about 341 to about 682, or from about 341 to about 568, or from about 114 to about 1000, or from about 114 to about 950, or from about 114 to about 910, or from about 114 to about 800, or from about 114 to about 690, or from about 114 to about 575.In some embodiments of the IL-2 conjugates described herein, n in the compounds of formula (XVI) and (XVII) is 2, 5, 10, 11, 22, 23, 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, 1249, 1250, 1251, 1362, 1363, 1364, is an integer selected from 1476, 1477, 1478, 1589, 1590, 1591, 1703, 1704, 1705, 1817, 1818, 1819, 1930, 1931, 1932, 2044, 2045, 2046, 2158, 2159, 2160, 2271, 2272, 2273, 2839, 2840, 2841, 2953, 2954, 2955, 3408, 3409, 3410, 3976, 3977, 3978, 4544, 4545, and 4546.

[0050] In some embodiments, described herein are IL-2 conjugates comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with a structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), wherein the replaced amino acid residue in SEQ ID NO: 3 is selected from H15, and n is an integer from about 450 to about 800, or from about 454 to about 796, or from about 454 to about 682, or from about 568 to about 909. In some embodiments of the IL-2 conjugates described herein, n in the compounds of formula (XVI) and (XVII) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, and 1249.

[0051] In some embodiments, described herein are IL-2 conjugates comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with a structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), wherein the replaced amino acid residue in SEQ ID NO: 3 is selected from H15, and n is an integer from about 450 to about 800, or from about 454 to about 796, or from about 454 to about 682, or from about 568 to about 909. In some embodiments of the IL-2 conjugates described herein, n in the compounds of formula (XVI) and (XVII) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910.

[0052] In some embodiments, described herein are IL-2 conjugates comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with a structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), where the replaced amino acid residue in SEQ ID NO: 3 is H15, and n is an integer from about 450 to about 800, or from about 454 to about 796, or from about 454 to about 682, or from about 568 to about 909. In some embodiments of the IL-2 conjugates described herein, n in the compounds of formula (XVI) and (XVII) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910. In some embodiments, n is from about 500 to about 1000. In some embodiments, n is about 550 to about 800. In some embodiments, n is about 681.

[0053] In some embodiments of the IL-2 conjugates described herein, the positions of the structures of formula (XVI) and (XVII) or a mixture of formula (XVI) and (XVII) in the amino acid sequence of the IL-2 conjugate comprising SEQ ID NO: 4 are: A1, P2, T3, S4, S5, S6, T7, K8, K9, Q11, L12, E15, H16, L18, L19, D20, Q22, M23, N26, G27, N29, N30, Y31, K32, K35, T37, M46, P47, K48, A50, T51, E52, L53, H55, Q57, E60 , E67, N71, Q74, S75, K76, N77, F78, H79, R81, P82, R83, D84, S87, N88, I89, V91, I92, L94, E95, K97, G98, S99, E100, T101, T102, F103, M104, C105, E106, Y107, A108, D109, D109, E110, T111, A112, T113, E116, N119, R120, T123, S125, Q126, S127, S130, T131, L132, and T133 in the N88R variant. Further described herein are IL-2 conjugates wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is selected from K9, H16, L19, D20, M23, N26, N88, V91, I92, L94, E95, K97, G98, S99, E100, D109 in the N88R variant, N119, T123, S125, Q126, S127, S130, and T131. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is selected from K9, H16, L19, D20, M23, N26, N88, V91, E100, D109 in the N88R variant, N119, T123, S125, and T131. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is K9.Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is H16. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is L19. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is D20. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII) in the amino acid sequence of the IL-2 conjugate is M23. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is N26. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is N88. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is V91. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII) in the amino acid sequence of the IL-2 conjugate is E100. Further described herein is an IL-2 conjugate, wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is D109 in the N88R variant.Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is N119. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is T123. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is S125. Further described herein are IL-2 conjugates, wherein the position of the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), in the amino acid sequence of the IL-2 conjugate is T131.

[0054] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3 or SEQ ID NO:4, wherein at least one amino acid residue in the IL-2 conjugate is replaced with a structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), and n is a number ranging from about 1,000 daltons to about 200,000 daltons, or from about 2,000 daltons to about 150,000 daltons, or from about 3,000 daltons to about 125,000 daltons, or from about 4,000 daltons to about 100,000 daltons. , or about 5,000 daltons to about 100,000 daltons, or about 6,000 daltons to about 90,000 daltons, or about 7,000 daltons to about 80,000 daltons, or about 8,000 daltons to about 70,000 daltons, or about 5,000 daltons to about 70,000 daltons, or about 5,000 daltons to about 65,000 daltons, or about 5,000 daltons to about 60,000 daltons, or about 5,000 daltons to about 50,000 daltons, or about 6,000 daltons to about 50,000 daltons, or about 7,000 daltons 1000 daltons to about 50,000 daltons, or about 7,000 daltons to about 45,000 daltons, or about 7,000 daltons to about 40,000 daltons, or about 8,000 daltons to about 40,000 daltons, or about 8,500 daltons to about 40,000 daltons, or about 8,500 daltons to about 35,000 daltons, or about 9,000 daltons to about 50,000 daltons, or about 9,000 daltons to about 45,000 daltons, or about 9,000 daltons to about 40,000 daltons, or about 9,000 daltons to about 35,000 daltons or about 9,000 daltons to about 30,000 daltons, or about 9,500 daltons to about 35,000 daltons, or about 9,500 daltons to about 30,000 daltons, or about 10,000 daltons to about 50,000 daltons, or about 10,000 daltons to about 45,000 daltons, or about 10,000 daltons to about 40,000 daltons, or about 10,000 daltons to about 35,000 daltons, or about 10,000 daltons to about 30,000 daltons, or about 15,000 daltons to about 50,000 daltons, or about 15,The integer is in the range of about 1,000 daltons to about 45,000 daltons, or about 15,000 daltons to about 40,000 daltons, or about 15,000 daltons to about 35,000 daltons, or about 15,000 daltons to about 30,000 daltons, or about 20,000 daltons to about 50,000 daltons, or about 20,000 daltons to about 45,000 daltons, or about 20,000 daltons to about 40,000 daltons, or about 20,000 daltons to about 35,000 daltons, or about 20,000 daltons to about 30,000 daltons. Described herein are IL-2 conjugates comprising the amino acid sequence of SEQ ID NO:3 or SEQ ID NO:4, wherein at least one amino acid residue in the IL-2 conjugate is replaced with a structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), and n is a number ranging from about 5,000 daltons, about 7,500 daltons, about 10,000 daltons, about 15,000 daltons, about 20,000 daltons, or about 30,000 daltons. daltons, about 25,000 daltons, about 30,000 daltons, about 35,000 daltons, about 40,000 daltons, about 45,000 daltons, about 50,000 daltons, about 60,000 daltons, about 70,000 daltons, about 80,000 daltons, about 90,000 daltons, about 100,000 daltons, about 125,000 daltons, about 150,000 daltons, about 175,000 daltons or about 200,000 daltons. Described herein are IL-2 conjugates comprising the amino acid sequence of SEQ ID NO:3 or SEQ ID NO:4, wherein at least one amino acid residue in the IL-2 conjugate is replaced with a structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), and n is an integer such that the molecular weight of the PEG moiety is about 5,000 daltons, about 7,500 daltons, about 10,000 daltons, about 15,000 daltons, about 20,000 daltons, about 25,000 daltons, about 30,000 daltons, about 35,000 daltons, about 40,000 daltons, about 45,000 daltons, or about 50,000 daltons.

[0055] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 4, wherein at least one amino acid residue in the IL-2 conjugate is replaced with a structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), wherein the amino acid residue in SEQ ID NO: 4 is H16, m is an integer from 1 to 6, and n is an integer from about 450 to about 800, or from about 454 to about 796, or from about 454 to about 682, or from about 568 to about 909. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XVI) and (XVII), m is 2 and n is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, and 1249.

[0056] In some embodiments, described herein are IL-2 conjugates comprising the amino acid sequence of SEQ ID NO: 4, wherein at least one amino acid residue in the IL-2 conjugate is replaced with a structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), wherein the replaced amino acid residue in SEQ ID NO: 4 is H16, m is an integer from 1 to 6, and n is an integer from about 450 to about 800, or from about 454 to about 796, or from about 454 to about 682, or from about 568 to about 909. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XVI) and (XVII), m is 2 and n is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910.

[0057] In some embodiments, described herein are IL-2 conjugates comprising the amino acid sequence of SEQ ID NO: 4, wherein at least one amino acid residue in the IL-2 conjugate is replaced with a structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), wherein the replaced amino acid residue in SEQ ID NO: 4 is E61, m is an integer from 1 to 6, and n is an integer from about 450 to about 800, or from about 454 to about 796, or from about 454 to about 682, or from about 568 to about 909. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XVI) and (XVII), m is 2 and n is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910. In some embodiments, n is from about 500 to about 1000. In some embodiments, n is from about 550 to about 800. In some embodiments, n is about 681.

[0058] Described herein is a method of treating an autoimmune disease in a subject, comprising administering to a subject in need thereof a therapeutically effective amount of an IL-2 conjugate described herein. Further described herein is a method of treating an autoimmune disease, including graft-versus-host disease (GVHD), atopic dermatitis, Crohn's disease, alopecia areata, autoimmune hemolytic anemia, autoimmune hepatitis, dermatomyositis, type 1 diabetes, juvenile / childhood type 1 diabetes, juvenile idiopathic arthritis, glomerulonephritis, Graves' disease, Guillain-Barré syndrome, idiopathic thrombocytopenic purpura, myasthenia gravis, multiple sclerosis, pemphigus / pemphigoid, pernicious anemia, polyarteritis nodosa, polymyositis, and primary biliary cholangitis. , primary biliary cirrhosis, non-alcoholic steatohepatitis (NASH), psoriasis, rheumatoid arthritis, scleroderma, CREST syndrome, Sjogren's syndrome, systemic lupus erythematosus, thyroiditis, uveitis, vitiligo, Wegener's granulomatosis, Addison's disease (adrenal insufficiency), Hashimoto's thyroiditis, autoimmune hepatitis, infertility, ANCA-associated vasculitis, psoriatic arthritis, celiac disease, ulcerative colitis, lichen sclerosus, and Behcet's disease. Further described herein is a method wherein the autoimmune disease is selected from the group consisting of graft-versus-host disease (GVHD), atopic dermatitis, Crohn's disease, type 1 diabetes, multiple sclerosis, rheumatoid arthritis, myasthenia gravis, primary biliary cirrhosis, nonalcoholic steatohepatitis (NASH), glomerulonephritis, idiopathic thrombocytopenic purpura, systemic lupus erythematosus, scleroderma, CREST syndrome, psoriasis, celiac disease, ulcerative colitis, pemphigus, psoriatic arthritis, and infertility. Further described herein is a method wherein the autoimmune disease is graft-versus-host disease (GVHD). Further described herein is a method wherein the autoimmune disease is atopic dermatitis. Further described herein is a method wherein the autoimmune disease is Crohn's disease. Further described herein is a method wherein the autoimmune disease is type 1 diabetes. Further described herein are methods, wherein the autoimmune disease is multiple sclerosis. Further described herein are methods, wherein the autoimmune disease is rheumatoid arthritis. Further described herein are methods, wherein the autoimmune disease is myasthenia gravis.Further described herein is a method wherein the autoimmune disease is primary biliary cholangitis or primary biliary cirrhosis. Further described herein is a method wherein the autoimmune disease is nonalcoholic steatohepatitis (NASH). Further described herein is a method wherein the autoimmune disease is glomerulonephritis. Further described herein is a method wherein the autoimmune disease is idiopathic thrombocytopenic purpura. Further described herein is a method wherein the autoimmune disease is systemic lupus erythematosus. Further described herein is a method wherein the autoimmune disease is scleroderma. Further described herein is a method wherein the autoimmune disease is CREST syndrome. Further described herein is a method wherein the autoimmune disease is infertility. Further described herein are methods in which an IL-2 conjugate is administered to a subject in need thereof once per week, once every two weeks, once every three weeks, once every four weeks, once every five weeks, once every six weeks, once every seven weeks, or once every eight weeks. Further described herein are methods in which an IL-2 conjugate is administered to a subject in need thereof once per week, once every two weeks, once every three weeks, or once every four weeks. Further described herein are methods in which an IL-2 conjugate is administered to a subject in need thereof once per week. Further described herein are methods in which an IL-2 conjugate is administered to a subject in need thereof once every two weeks. Further described herein are methods in which an IL-2 conjugate is administered to a subject in need thereof once every three weeks. Further described herein is a method in which an IL-2 conjugate is administered to a subject in need thereof once every four weeks. Further described herein is a method in which a subject in need thereof is determined to exhibit an increased concentration of rheumatoid factor in the subject's blood prior to administration of a therapeutically effective amount of an IL-2 conjugate to the subject. Further described herein is a method in which the increased concentration of rheumatoid factor in the subject's blood is about 14 IU / mL or higher, or about 15 IU / mL or higher.Further described herein are methods wherein the increased concentration of rheumatoid factor in the subject's blood is about 14 IU / mL or greater. Further described herein are methods wherein the increased concentration of rheumatoid factor in the subject's blood is about 15 IU / mL or greater.

[0059] Described herein are methods for treating rheumatoid arthritis in a subject in need thereof, comprising: (a) determining the concentration of rheumatoid factor in the subject's blood; and (b) administering to the subject in need thereof a therapeutically effective amount of an IL-2 conjugate described herein if the concentration of rheumatoid factor in the subject's blood is greater than about 14 IU / mL. Further described herein are methods in which a therapeutically effective amount of an IL-2 conjugate is administered to the subject in need thereof if the concentration of rheumatoid factor in the subject's blood is greater than about 15 IU / mL.

[0060] Described herein are methods of treating rheumatoid arthritis in a subject in need thereof, comprising administering to the subject in need thereof a therapeutically effective amount of an IL-2 conjugate described herein when the concentration of rheumatoid factor in the subject's blood is determined to be greater than about 14 IU / mL.

[0061] Described herein are methods for treating rheumatoid arthritis in a subject in need thereof, comprising administering to the subject a therapeutically effective amount of an IL-2 conjugate described herein when the concentration of rheumatoid factor in the subject's blood is determined to be greater than about 15 IU / mL. Further provided herein are methods in which the subject in need thereof is determined to have an abnormal erythrocyte sedimentation rate (ESR) test prior to administering a therapeutically effective amount of an IL-2 conjugate to the subject. Further described herein are methods in which the subject is determined to have an abnormal erythrocyte sedimentation rate (ESR) test using the Westergren rate method prior to administering a therapeutically effective amount of an IL-2 conjugate to the subject. Further described herein are methods in which the subject is determined to have an abnormal erythrocyte sedimentation rate (ESR) test using the Wintrobe rate method prior to administering a therapeutically effective amount of an IL-2 conjugate to the subject. Further provided herein is a method wherein the subject is a female under 50 years of age and exhibits a Westergren velocity greater than about 20 mm / hr. Further provided herein is a method wherein the subject is a female over 50 years of age and exhibits a Westergren velocity greater than about 30 mm / hr. Further provided herein is a method wherein the subject is a male under 50 years of age and exhibits a Westergren velocity greater than about 15 mm / hr. Further provided herein is a method wherein the subject is a male over 50 years of age and exhibits a Westergren velocity greater than 20 mm / hr. Further provided herein is a method wherein the subject is a child and exhibits a Westergren velocity greater than about 10 mm / hr.

[0062] Described herein are methods for treating an autoimmune disease in a subject in need thereof, comprising: (a) determining the erythrocyte sedimentation rate (ESR) in the subject; and (b) administering to the subject in need thereof a therapeutically effective amount of an IL-2 conjugate described herein if the ESR is determined to be abnormal. Further described herein are methods wherein the subject is determined to have an abnormal erythrocyte sedimentation rate (ESR) test using the Wintrobe rate method. Further described herein are methods wherein the subject is determined to have an abnormal erythrocyte sedimentation rate (ESR) test using the Westergren rate method. Further described herein are methods wherein the subject is a female under 50 years of age and has a Westergren rate greater than about 20 mm / hr. Further described herein are methods wherein the subject is a female over 50 years of age and has a Westergren rate greater than about 30 mm / hr. Further described herein are methods wherein the subject is a male under 50 years of age and exhibits a Westergren velocity greater than about 15 mm / hr. Further described herein are methods wherein the subject is a male over 50 years of age and exhibits a Westergren velocity greater than 20 mm / hr. Further described herein are methods wherein the subject is a child and exhibits a Westergren velocity greater than about 10 mm / hr. Further described herein are methods wherein a subject in need thereof is determined to exhibit an increased concentration of C-reactive protein (CRP) in the subject's blood prior to administration of a therapeutically effective amount of an IL-2 conjugate to the subject. Further described herein are methods wherein a subject in need thereof is determined to exhibit a concentration of C-reactive protein (CRP) in the blood greater than 10 mg / L prior to administration of a therapeutically effective amount of an IL-2 conjugate to the subject.

[0063] Described herein are methods of treating an autoimmune disease in a subject in need thereof, comprising: (a) determining the concentration of C-reactive protein (CRP) in the subject's blood; and (b) administering to the subject in need thereof a therapeutically effective amount of an IL-2 conjugate described herein if the concentration of C-reactive protein (CRP) in the subject's blood is determined to be abnormal. Further described herein are methods wherein the subject in need thereof is determined to exhibit a concentration of C-reactive protein (CRP) in the blood greater than 10 mg / L prior to administration of a therapeutically effective amount of an IL-2 conjugate to the subject.

[0064] Described herein is a method for treating rheumatoid arthritis in a subject in need thereof, comprising: (a) determining the concentration of anti-cyclic citrullinated peptide (anti-CCP) in the subject's blood; and (b) administering to the subject in need thereof a therapeutically effective amount of an IL-2 conjugate described herein if the concentration of anti-cyclic citrullinated peptide (anti-CCP) in the subject's blood is determined to be abnormal. Further described herein is a method in which a therapeutically effective amount of an IL-2 conjugate is administered to the subject in need thereof if the concentration of anti-cyclic citrullinated peptide (anti-CCP) in the subject's blood is determined to be greater than about 20 Iu / mL.

[0065] Described herein are methods of treating rheumatoid arthritis in a subject in need thereof, comprising administering to the subject in need thereof a therapeutically effective amount of an IL-2 conjugate described herein when the concentration of anti-cyclic citrullinated peptide (anti-CCP) in the subject's blood is determined to be abnormal.

[0066] Described herein are methods for treating rheumatoid arthritis in a subject in need thereof, comprising administering to the subject in need thereof a therapeutically effective amount of an IL-2 conjugate described herein when the concentration of anti-cyclic citrullinated peptide (anti-CCP) in the subject's blood is determined to be greater than about 20 Iu / mL. Further described herein are methods wherein the autoimmune disease is psoriasis. Further described herein are methods wherein the autoimmune disease is celiac disease. Further described herein are methods wherein the autoimmune disease is ulcerative colitis. Further described herein are methods wherein the autoimmune disease is pemphigus.

[0067] Described herein are methods for reducing or eliminating an autoimmune condition modeled, manifested, and / or characterized by delayed-type hypersensitivity (DTH) in a subject in need thereof, comprising administering to the subject a therapeutically effective amount of an IL-2 conjugate described herein.

[0068] The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings. [Brief explanation of the drawings]

[0069] [Figure 1]

[0023] Figure 1 shows exemplary unnatural amino acids. This figure is reproduced from Figure 2 in Young et al., "Beyond the canonical 20 amino acids: expanding the genetic lexicon," J. of Biological Chemistry 285(15):11039-11044 (2010). [Figure 2-1] 2A-2B show exemplary unnatural amino acids, where Figure 2A shows an exemplary lysine derivative, and Figure 2B shows an exemplary phenylalanine derivative. [Figure 2-2] Continued from Figure 2-1. [Figure 2-3] Continued from Figure 2-2. [Figure 3-1] Figures 3A-3D show exemplary unnatural amino acids. These unnatural amino acids (UAAs) are genetically encoded in proteins (Figure 3A - UAA numbers 1-42; Figure 3B - UAA numbers 43-89; Figure 3C - UAA numbers 90-128; Figure 3D - UAA numbers 129-167). Figures 3A-3D are reprinted from Table 1 in Dumas et al., Chemical Science 2015, 6, pp. 50-69. [Figure 3-2] Continued from Figure 3-1. [Figure 3-3] Continued from Figure 3-2. [Figure 3-4] Continued from Figure 3-3. [Figure 3-5] Continued from Figure 3-4. [Figure 3-6] Continued from Figure 3-5. [Figure 3-7] Continued from Figure 3-6. [Figure 4] 4A-4B show dose-response curves of representative IL-2 variants for pSTAT5 signaling in human LRS primary cells (FIG. 4A) and the proliferative response in murine CTLL-2 populations (FIG. 4B). [Figure 5A] Figures 5A and 5B show plots from screening for functional activity of IL-2 conjugates conducted at Discoverx (Fremont, CA) using the PathHunter IL-2 cytokine receptor assay of Example 3. Figure 5A shows plots generated from assays with IL-2 and IL-2 conjugate D20_30kD. [Figure 5B]Figure 5B shows plots from screening for functional activity of IL-2 conjugates conducted at Discoverx (Fremont, CA) using the PathHunter IL-2 cytokine receptor assay of Example 3. Figure 5B shows plots generated from assays with IL-2 conjugates H16_30kD and L19_30kD. [Figure 5C] Figure 5C shows plots from screening for functional activity of IL-2 conjugates conducted at Discoverx (Fremont, CA) using the PathHunter IL-2 cytokine receptor assay of Example 3. Figure 5C shows plots generated from assays with IL-2 conjugates N88_30kD and L12_30kD. X-axis: pg / ml. Y-axis: % of maximal response. [Figure 6] FIG. 1 shows the plasma concentration profiles of IL-2 conjugates K9_30kD, L19_30kD, N88R / D109_30kD, H16_30kD, Q126_30kD, and N88_30kD (all dosed at 0.9 mg / kg) after administration to C57 / BL6 mice in Example 4. [Figure 7] FIG. 1 shows the mean fold change in Tregs (% in singlets) after administration of IL-2 conjugates to C57 / BL6 mice in Example 4. [Figure 8] FIG. 10 is a diagram showing the percentage of Treg (CD3+CD4+CD25+FoxP3+) cell population in the total cell population (singlets) of IL-2 conjugates in C57 / BL6 mice in Example 4. [Figure 9A] FIG. 1 shows the percentage of CD8+ T cell population (CD3+CD4−CD8+) in the total cell population (singlets) after a single administration of IL-2 conjugates K9_30kD, L19_30kD, Q126_30kD, and H16_30kD in C57 / BL6 mice in Example 4. [Figure 9B]FIG. 1 shows the percentage of CD8+ T cell (CD3+CD4−CD8+) population in the total cell population (singlets) after single administration of IL-2 conjugates E100_30kD, N88R / D109_30kD, T123_30kD, N88_30kD, and V91_30kD in C57 / BL6 mice in Example 4. [Figure 10] FIG. 1 shows the plasma concentration profile of the IL-2 conjugate after administration to cynomolgus monkeys in Example 5. [Figure 11] FIG. 1 shows the percentage of Treg cell population in the total blood cell population (singlets) in cynomolgus monkeys after treatment with the IL-2 conjugate of Example 5. [Figure 12] FIG. 1 shows the percentage of CD8+ T cell population in the total blood cell population (singlets) in cynomolgus monkeys after treatment with the IL-2 conjugate of Example 5. [Figure 13] FIG. 1 shows a plot of plasma concentration versus time for H16_30kD variant administered at doses of 0.12 mg / kg and 0.67 mg / kg in non-human primates from Example 6, with the 0.12 mg / kg dose represented as the lower trace and the 0.67 mg / kg dose represented as the upper trace. [Figure 14] FIG. 1 shows plots of plasma concentration versus time for the H16_30kDa and dH16_50kDa variants administered at a dose of 0.12 mg / kg, and the H16_50kDa variant administered at a dose of 0.2 mg / kg in non-human primates of Example 6, where the trace for the 30kDa variant is represented as the lower trace (squares) and the trace for the 50kDa variant is represented as the upper trace (triangles). [Figure 15]FIG. 10 shows plots of single Treg percentage (%) versus time post-administration for the H16_30kDa variant administered at a dose of 0.12 mg / kg and the H16_50kDa variant administered at a dose of 0.2 mg / kg in non-human primates in Example 6, where the trace for vehicle is the lower trace (square), the trace for the 30kDa variant is represented by the middle trace, and the trace for the 50kDa variant is represented by the upper trace. [Figure 16] 1 shows the study design of Example 7 to evaluate the effect of H16_50kD on delayed-type hypersensitivity (DTH) in C57BL / 6 mice. DTH was induced in mice using H16_50kD of Example 7 at doses of 0.03 mg / kg, 0.1 mg / kg, and 0.3 mg / kg (days 0 and 3) in conjunction with keyhole limpet hemocyanin (KLH) (sensitization by subcutaneous injection on day 1 followed by challenge on day 7). [Figure 17A] Figures 17A and 17B show changes in ear thickness measurements and blood immune types of C57BL / 6 mice from Example 7. Figure 17A shows the area under the curve (AUC) of ear thickness increase compared to mice receiving only the KLH challenge on day 7. [Figure 17B] Figures 17A and 17B show changes in ear thickness measurements and blood immune types of C57BL / 6 mice from Example 7. Figure 17B shows changes in ear thickness measurements of C57BL / 6 mice before KLH challenge (day 7) and on days 8, 9, and 10 thereafter. [Figure 17C]Figure 17C shows the changes in ear thickness measurements and blood immune types of C57BL / 6 mice in Example 7. Figure 17C shows the time course of the relative percentage (%) of CD4+ T cells in the CD25+FoxP3+ cell population in whole blood samples obtained from mice. "KLH only" indicates that only KLH challenge on day 7 (without sensitization on day 1) was performed with administration of vehicle only. "Vehicle" indicates that KLH sensitization (day 1) and challenge (day 7) were performed with administration of vehicle only. "0.03" indicates that KLH sensitization and challenge were performed with administration of H16_50kD at a dose of 0.03 mg / kg. "0.1" indicates that KLH sensitization and challenge were performed with administration of H16_50kD at a dose of 0.1 mg / kg. "0.3" indicates that KLH sensitization and challenge were performed in conjunction with administration of H16_50kD at a dose of 0.3 mg / kg. "CsA" indicates that KLH sensitization and challenge were performed in conjunction with administration of cyclosporine A. See also Table 10 in Example 7. [Figure 18A] 18A and 18B show the relative percentages of CD4+CD25+FoxP3+ cells over time in the CD45+ (FIG. 18A), TCRβ+ (FIG. 18B), and CD4+ (FIG. 18C) cell populations of whole blood samples obtained from mice in Example 7. [Figure 18B] 18A and 18B show the relative percentages of CD4+CD25+FoxP3+ cells over time in the CD45+ (FIG. 18A), TCRβ+ (FIG. 18B), and CD4+ (FIG. 18C) cell populations of whole blood samples obtained from mice in Example 7. [Figure 18C] 18A and 18B show the relative percentages of CD4+CD25+FoxP3+ cells over time in the CD45+ (FIG. 18A), TCRβ+ (FIG. 18B), and CD4+ (FIG. 18C) cell populations of whole blood samples obtained from mice in Example 7. [Figure 19] FIG. 10 shows absolute counts of CD4+CD25+FoxP3+ cells in whole blood samples obtained from mice on day 10 in Example 7. DETAILED DESCRIPTION OF THE INVENTION

[0070] Cytokines include a family of cell signaling proteins, such as chemokines, interferons, interleukins, lymphokines, tumor necrosis factors, and other growth factors that play a role in innate and adaptive immune cell homeostasis. Cytokines are produced by immune cells, such as macrophages, B lymphocytes, T lymphocytes, and mast cells, endothelial cells, fibroblasts, and various stromal cells. In some instances, cytokines regulate the balance between humoral and cellular immune responses.

[0071] Interleukins are signaling proteins that regulate the development and differentiation of T and B lymphocytes, cells of the monocyte lineage, neutrophils, basophils, eosinophils, megakaryocytes, and hematopoietic cells. Interleukins are produced by helper CD4 T and B lymphocytes, monocytes, macrophages, endothelial cells, and other tissue residents.

[0072] Interleukin-2 (IL-2) is a pleiotropic type-1 cytokine whose structure contains a four-α-helical bundle of 15.5 kDa. The precursor of IL-2 is 153 amino acid residues in length, with the first 20 amino acids forming a signal peptide and residues 21–153 forming the mature form. IL-2 is produced primarily by CD4+ T cells after antigen stimulation, and to a lesser extent by CD8+ cells, natural killer (NK) cells, and natural killer T (NKT) cells, activated dendritic cells (DCs), and mast cells. IL-2 signaling occurs through interaction with a specific combination of IL-2 receptor (IL-2R) subunits, IL-2Rα (also known as CD25), IL-2Rβ (also known as CD122), and IL-2Rγ (also known as CD132). The interaction of IL-2 with IL-2Rα is approximately 10 -8 K of M dThe interaction of IL-2 with IL-2Rβ and IL-2Rγ occurs at approximately 10 -9 K of M d The interaction of IL-2 with all three subunits, IL-2Rα, IL-2Rβ, and IL-2Rγ, occurs at approximately >10 -11 K of M d form a "high affinity" IL-2 receptor complex.

[0073] In some instances, IL-2 signaling through the "high affinity" IL-2Rαβγ complex regulates the activation and proliferation of regulatory T cells, or CD4 + CD25 + Foxp3 + Regulatory T (Treg) cells are effector cells, e.g., CD4 + T cells, CD8 + They mediate the maintenance of immune homeostasis by suppressing T cells, B cells, NK cells, and NKT cells. In some instances, Treg cells arise from the thymus (tTreg cells) or are derived from naive T cells in the periphery (pTreg cells). In some cases, Treg cells are considered mediators of peripheral tolerance. Indeed, one study showed that CD25-depleted peripheral CD4 + T cell transplantation induces various autoimmune diseases in nude mice, while CD4 + CD25 + Cotransplantation of T cells suppressed the development of autoimmunity (Sakaguchi, et al., "Immunologic self-tolerance maintained by activated T cells expressing IL-2 receptor alpha-chains (CD25)," J. Immunol. 155(3):1151-1164 (1995)). Expansion of the Treg cell population down-regulates effector T cell proliferation and suppresses autoimmunity and T cell antitumor responses.

[0074] Disclosed herein, in certain embodiments, are methods for selectively upregulating distinct populations of lymphocytes (e.g., CD4+ helper cells, CD8+ effector naive and memory cells, NK cells, or NKT cells) via cytokine / cytokine receptor signaling. In some examples, the cytokine comprises an interleukin, an interferon, or a tumor necrosis factor. In some cases, the cytokine is a cytokine conjugate, such as an interleukin conjugate, an interferon conjugate, or a tumor necrosis factor conjugate. Additionally, included herein are pharmaceutical compositions and kits comprising one or more cytokine conjugates described herein.

[0075] Also described herein in some embodiments are methods of selectively upregulating CD4+ helper cells, CD8+ effector naive and memory cells, NK cells, and / or NKT cell populations via IL-2 / IL-2R signaling. In some examples, the IL-2 is an IL-2 conjugate that interacts with the "intermediate affinity" IL-2Rβγ complex, optionally with potency similar to the IL-2Rαβγ complex and with weaker IL-2Rα interaction compared to wild-type IL-2. Further described herein in some embodiments are methods of treating cancer using the IL-2 conjugates described herein. In additional embodiments, described herein are pharmaceutical compositions and kits comprising one or more IL-2 conjugates described herein. In some embodiments, the IL-2 conjugates include a conjugated moiety (e.g., PEG) that contributes to an increased or decreased "clearance rate" or plasma half-life in a subject without affecting pharmacokinetics, including desired cytokine-receptor interaction and immune cell expansion.

[0076] Cytokine Conjugates In some embodiments, described herein are cytokine conjugates. In some instances, the cytokine comprises an interleukin, tumor necrosis factor, interferon, chemokine, lymphokine, or growth factor. In some instances, the cytokine is an interleukin. In some instances, the cytokine is an interferon. In additional instances, the cytokine is a tumor necrosis factor. In further instances, the cytokine is a growth factor.

[0077] In some embodiments, described herein are interleukin conjugates. Exemplary interleukins include, but are not limited to, interleukin 2 (IL-2).

[0078] IL-2 conjugates Described herein are the polypeptides shown in Table 1. In some embodiments, the IL-2 conjugates described herein are exemplified in Table 1.

[0079] [Table 1-1] [Table 1-2] [Table 1-3] [Table 1-4] [Table 1-5] [Table 1-6] [Table 1-7] [Table 1-8] [Table 1-9] [Table 1-10] [Table 1-11] [Table 1-12] [Table 1-13] [Table 1-14] [Table 1-15] [Table 1-16] [Table 1-17] [Table 1-18] [Table 1-19] [Table 1-20] [Table 1-21] [AzK]=N6-((2-azidoethoxy)-carbonyl)-L-lysine, having Chemical Abstracts Registry Number 1167421-25-1. (The structure is disclosed as Compound 90 in Figure 3C.) [AzK_PEG]=N6-((2-azidoethoxy)-carbonyl)-L-lysine is stably conjugated to PEG via DBCO-mediated click chemistry to form a compound comprising the structure of formula (II) or formula (III). For example, PEG50kD is specified to represent a linear polyethylene glycol chain having an average molecular weight of 50 kDa and capped with a methoxy group. The ratio of positional isomers produced from the click reaction is about 1:1 or greater. The term "DBCO" refers to a chemical moiety comprising a dibenzocyclooctyne group, including, for example, the mPEG-DBCO compound shown in Scheme 1 of Example 1. An exemplary structure of a methoxy PEG group is shown in the mPEG-DBCO structure in Scheme 1 of Example 1. [AzK_L1_PEG]=N6-((2-azidoethoxy)-carbonyl)-L-lysine is stably conjugated to PEG via DBCO-mediated click chemistry to form a compound comprising the structure of formula (IV) or formula (V). For example, PEG50kD is specified to represent a linear polyethylene glycol chain having an average molecular weight of 50 kDa and capped with a methoxy group. The ratio of positional isomers produced from the click chemistry reaction is about 1:1 or greater. The term "DBCO" refers to a chemical moiety comprising a dibenzocyclooctyne group, for example, the mPEG-DBCO compound shown in Scheme 1 of Example 1.

[0080] In some embodiments, the present specification describes IL-2 conjugates modified at an amino acid position. In some examples, the modification is a change to a natural amino acid. In some examples, the modification is a change to a non-natural amino acid. In some examples, the present specification describes isolated and modified IL-2 polypeptides comprising at least one non-natural amino acid. In some examples, the IL-2 polypeptide is isolated and purified mammalian IL-2, e.g., rodent IL-2 protein, or human IL-2 protein. In some cases, the IL-2 polypeptide is a human IL-2 protein. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity to SEQ ID NO: 1. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 1. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 1. In additional cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity to SEQ ID NO:2. In additional cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO:2. In additional cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO:2. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity to SEQ ID NO:3. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO:3. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO:3. In additional cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity to SEQ ID NO:4. In additional cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO:4. In additional instances, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 4. In some instances, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity to SEQ ID NOs: 34-48. In some instances, the IL-2 polypeptide comprises the sequence of SEQ ID NOs: 34-48. In some instances, the IL-2 polypeptide consists of the sequence of SEQ ID NOs: 34-48.In additional cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity to SEQ ID NOs: 199-213. In additional cases, the IL-2 polypeptide comprises the sequence of SEQ ID NOs: 199-213. In additional cases, the IL-2 polypeptide consists of the sequence of SEQ ID NOs: 199-213. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity to SEQ ID NOs: 49-63. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NOs: 49-63. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NOs: 49-63. In additional cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity to SEQ ID NOs: 213-228. In additional cases, the IL-2 polypeptide comprises the sequence of SEQ ID NOs: 213-228. In additional cases, the IL-2 polypeptide consists of the sequence of SEQ ID NOs: 213-228. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity to SEQ ID NOs: 64-78. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NOs: 64-78. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NOs: 64-78. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity to SEQ ID NOs: 229-243. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NOs: 229-243. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NOs: 229-243. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity to SEQ ID NOs: 154-168. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NOs: 154-168. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NOs: 154-168. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity to SEQ ID NOs: 109-123.In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 109-123. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 109-123. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity to SEQ ID NO: 169-183. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 169-183. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 169-183. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity to SEQ ID NO: 123-138. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 123-138. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 123-138. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity to SEQ ID NOs: 184-198. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NOs: 184-198. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NOs: 184-198. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity to SEQ ID NOs: 139-153. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NOs: 139-153. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NOs: 139-153.

[0081] In some examples, the IL-2 polypeptide is a truncated variant. In some examples, the truncation is an N-terminal deletion. In other examples, the truncation is a C-terminal deletion. In additional examples, the truncation includes deletion of both the N-terminus and the C-terminus. For example, the truncation can be deletion of at least or about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, or more residues from the N-terminus or C-terminus, or both. In some cases, the IL-2 polypeptide includes an N-terminal deletion of at least or about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, or more residues. In some cases, the IL-2 polypeptide includes an N-terminal deletion of at least or about 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 residues. In some cases, the IL-2 polypeptide includes an N-terminal deletion of at least or about 2 residues. In some cases, the IL-2 polypeptide comprises an N-terminal deletion of at least or about 3 residues. In some cases, the IL-2 polypeptide comprises an N-terminal deletion of at least or about 4 residues. In some cases, the IL-2 polypeptide comprises an N-terminal deletion of at least or about 5 residues. In some cases, the IL-2 polypeptide comprises an N-terminal deletion of at least or about 6 residues. In some cases, the IL-2 polypeptide comprises an N-terminal deletion of at least or about 7 residues. In some cases, the IL-2 polypeptide comprises an N-terminal deletion of at least or about 8 residues. In some cases, the IL-2 polypeptide comprises an N-terminal deletion of at least or about 9 residues. In some cases, the IL-2 polypeptide comprises an N-terminal deletion of at least or about 10 residues.

[0082] In some embodiments, the IL-2 polypeptide is a functionally active fragment. In some embodiments, the functionally active fragment comprises IL-2 region 10-133, 20-133, 30-133, 10-130, 20-130, 30-130, 10-125, 20-125, 30-125, 1-130, or 1-125, where the residue positions are relative to the positions in SEQ ID NO:1. In some embodiments, the functionally active fragment comprises IL-2 region 10-133, where the residue positions are relative to the positions in SEQ ID NO:1. In some embodiments, the functionally active fragment comprises IL-2 region 20-133, where the residue positions are relative to the positions in SEQ ID NO:1. In some embodiments, the functionally active fragment comprises IL-2 region 30-133, where the residue positions are relative to the positions in SEQ ID NO:1. In some cases, the functionally active fragment comprises IL-2 region 10-125, with the residue positions being relative to the positions in SEQ ID NO: 1. In some cases, the functionally active fragment comprises IL-2 region 20-125, with the residue positions being relative to the positions in SEQ ID NO: 1. In some cases, the functionally active fragment comprises IL-2 region 1-130, with the residue positions being relative to the positions in SEQ ID NO: 1. In some cases, the functionally active fragment comprises IL-2 region 1-125, with the residue positions being relative to the positions in SEQ ID NO: 1.

[0083] In some embodiments, described herein are IL-2 conjugates, including isolated, purified, and modified IL-2 polypeptides and conjugating moieties. In some examples, the IL-2 conjugates have reduced affinity for the IL-2 receptor alpha (IL-2Rα) subunit compared to wild-type IL-2 polypeptides. In some cases, the conjugating moiety binds to an amino acid residue that interacts with IL-2Rα (e.g., at the IL-2 / IL-2Rα interface). In some cases, the conjugating moiety binds to an amino acid residue proximal to the IL-2 / IL-2Rα interface (e.g., about 5 Å, about 10 Å, about 15 Å, or about 20 Å away from the IL-2 / IL-2Rα interface). As used herein, residues involved in the IL-2 / IL-2Rα interface include IL-2 residues that form hydrophobic interactions, hydrogen bonds, or ionic interactions with residues from the IL-2Rα subunit.

[0084] In some examples, the conjugation moiety is located at amino acid positions A1, P2, T3, S4, S5, S6, T7, K8, K9, Q11, L12, E15, H16, L18, L19, D20, Q22, M23, N26, G27, N29, N30, Y31, K32, K35, T37, M46, P47, K48, A50, T51, E52, L53, H55, Q57, E60, E67, N71, Q74, S75, K76, N77, F78, H79, R81, P82, R83, D84, S87, N88, I and binding to an amino acid residue selected from 89, V91, I92, L94, E95, K97, G98, S99, E100, T101, T102, F103, M104, C105, E106, Y107, A108, D109, D109, E110, T111, A112, T113, E116, N119, R120, T123, S125, Q126, S127, S130, T131, L132, or T133 in the N88R variant, wherein the numbering of the amino acid residues corresponds to SEQ ID NO: 1. In some examples, the amino acid positions are A1, P2, T3, S4, S5, S6, T7, K8, K9, Q11, L12, E15, H16, L18, L19, D20, Q22, M23, N26, G27, N29, N30, Y31, K32, K35, T37, M46, P47, K48, A50, T51, E52, L53, H55, Q57, E60, E67, N71, Q74, S75, K76, N77, F78, H79, R81, P82, R83, D 84, S87, N88, I89, V91, I92, L94, E95, K97, G98, S99, E100, T101, T102, F103, M104, C105, E106, Y107, A108, D109, D109 in the N88R variant, E110, T111, A112, T113, E116, N119, R120, T123, S125, Q126, S127, S130, T131, L132, and T133. In some examples, the amino acid positions are selected from A1, P2, T3, S4, S5, S6, T7, K8, K9, Q11, L12, E15, H16, L18, L19, D20, Q22, M23, N26, G27, N29, N30, and Y31.In some examples, the amino acid positions are K32, K35, T37, M46, P47, K48, A50, T51, E52, L53, H55, Q57, E60, E67, N71, Q74, S75, K76, N77, F78, H79, R81, P82, R83, D84, S87, N88, I89, V91, I92, L94, E95, K97, G98, S99 , E100, T101, T102, F103, M104, C105, E106, Y107, A108, D109, D109 in the N88R variant, E110, T111, A112, T113, E116, N119, R120, T123, S125, Q126, S127, S130, T131, L132, and T133. In some examples, the amino acid positions are selected from K9, Q11, L12, E15, H16, L18, L19, K35, T37, M46, P47, K48, A50, K76, N77, F78, H79, R81, P82, R83, D84, S87, N88, F103, M104, C105, E106, Y107, A108, D109, D109 in the N88R variant. In some examples, the amino acid positions are selected from S99, E100, T101, T102, F103, M104, C105, E106, Y107, A108, D109, D109 in the N88R variant, E110, T111, A112, T113, E116, N119, R120, T123, S125, Q126, S127, S130, T131, L132, and T133. In some examples, the amino acid positions are selected from K8, H15, L18, D19, M22, N25, N87, V90, I91, L93, E94, K96, G97, S98, E99, D108 in the N87R variant, N118, T122, S124, Q125, S126, S129, and T130.

[0085] In some examples, the IL-2 conjugate further comprises an additional mutation. In some cases, the additional mutation is at an amino acid position selected from K8, H15, L18, D19, M22, N25, N87, V90, I91, L93, E94, K96, G97, S98, E99, D108 in the N87R variant, N118, T122, S124, Q125, S126, S129, and T130. In such cases, the amino acid is conjugated to an additional conjugation moiety for increased serum half-life, stability, or a combination thereof. Alternatively, the amino acid is first mutated to a natural amino acid, such as lysine, cysteine, histidine, arginine, aspartic acid, glutamic acid, serine, threonine, or tyrosine; or to an unnatural amino acid before being attached to the additional conjugation moiety.

[0086] In some cases, receptor signaling potency is measured by ED50 value. In some cases, the modified IL-2 polypeptide provides a first ED50 value for activating the IL-2βγ signaling complex and a second ED50 value for activating the IL-2αβγ signaling complex, and the difference between the first ED50 value and the second ED50 value is less than 10-fold. In some cases, the modified IL-2 polypeptide provides a first ED50 value for activating the IL-2βγ signaling complex and a second ED50 value for activating the IL-2αβγ signaling complex, and the difference between the first ED50 value and the second ED50 value is less than 5-fold. In some cases, the difference is less than 9-fold, less than 8-fold, less than 7-fold, less than 6-fold, less than 5-fold, less than 4-fold, less than 3-fold, less than 2-fold, or less than 1-fold.

[0087] In some embodiments, the conjugation moiety is linked to the N-terminus or C-terminus of the IL-2 polypeptide, either directly or indirectly via a linker peptide. In some cases, the conjugation moiety (e.g., a polymer, protein, or peptide) is genetically fused to the N-terminus or C-terminus of IL-2, either directly or indirectly via a linker peptide. In some examples, the conjugation moiety is linked to the N-terminus or C-terminal amino acid residue. In some examples, the conjugation moiety is linked to a reactive group that binds to the N-terminus or C-terminal amino acid residue.

[0088] In some embodiments, IL-2 conjugates with reduced binding affinity to IL-2Rα can expand CD4+ helper cell, CD8+ effector naive and memory T cell, natural killer (NK) cell, or natural killer T (NKT) cell populations. In some cases, the conjugated moiety impairs or blocks binding of IL-2 to IL-2Rα.

[0089] In some cases, activation of CD4+ helper cells, CD8+ effector naive and memory cells, natural killer (NK) cells, or natural killer T (NKT) cell populations via the IL-2Rβγ complex by the modified IL-2 polypeptide retains significant potency of activation of the cell populations compared to wild-type IL-2 polypeptide. In some cases, activation by the modified IL-2 polypeptide is equivalent to that of the wild-type IL-2 polypeptide. In other cases, activation by the modified IL-2 polypeptide is greater than that of the wild-type IL-2 polypeptide. In some cases, the receptor signaling potency of the modified IL-2 polypeptide at the IL-2Rβγ complex is greater than that of the wild-type IL-2 polypeptide. In some cases, the receptor signaling potency of the modified IL-2 polypeptide is at least one-fold greater than that of the wild-type IL-2 polypeptide. In some cases, the receptor signaling potency of the modified IL-2 polypeptide is about or at least 2-fold, 3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold, 10-fold, 15-fold, 20-fold, 25-fold, 30-fold, 40-fold, 50-fold, 60-fold, 70-fold, 80-fold, 90-fold, 100-fold, 150-fold, 200-fold, 300-fold, 400-fold, 500-fold, 1,000-fold, or more than the respective potency of the wild-type IL-2 polypeptide. In such cases, the dose or concentration of the modified IL-2 polypeptide used to achieve similar levels of activation of CD4+ helper cells, CD8+ effector naive and memory cells, natural killer (NK) cells, or natural killer T (NKT) cell populations as the wild-type IL-2 polypeptide is lower than the dose or concentration used for the wild-type IL-2 polypeptide.

[0090] In some embodiments, activation of CD4+ helper cells, CD8+ effector naive and memory cells, natural killer (NK) cells, or natural killer T (NKT) cell populations via the IL-2Rβγ complex by a modified IL-2 polypeptide retains substantial potency of activation of said cell populations by a wild-type IL-2 polypeptide. In some cases, the receptor signaling potency of the modified IL-2 polypeptide at the IL-2Rβγ complex is lower than the receptor signaling potency of the wild-type IL-2 polypeptide at the IL-2Rβγ complex. In some cases, the receptor signaling potency of the modified IL-2 polypeptide is about or at least 1-fold, 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, 20-fold, or 50-fold lower than the respective potencies of the wild-type IL-2 polypeptide.

[0091] In some embodiments, the modified IL-2 polypeptide exhibits a first receptor signaling potency for IL-2βγ and a second receptor signaling potency for IL-2αβγ. In some examples, the first receptor signaling potency for IL-2Rβγ is improved potency compared to the wild-type IL-2 polypeptide. In some examples, the second receptor signaling potency for IL-2Rαβγ is impaired potency compared to the wild-type IL-2 polypeptide. In some embodiments, the modified IL-2 polypeptide exhibits a first receptor signaling potency for IL-2βγ and a second receptor signaling potency for IL-2Rαβγ, wherein the first receptor signaling potency is at least 1-fold, 2-fold, 3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold, 10-fold, 20-fold, 30-fold, 50-fold, 100-fold, 500-fold, 1000-fold, or more, greater than the second receptor signaling potency. In some examples, the first receptor signaling potency is at least 1-fold or more greater than the second receptor signaling potency. In some examples, the first receptor signaling potency is at least 2-fold or more greater than the second receptor signaling potency. In some examples, the first receptor signaling potency is at least 5-fold or more greater than the second receptor signaling potency. In some examples, the first receptor signaling potency is at least 10-fold or more greater than the second receptor signaling potency. In some examples, the first receptor signaling potency is at least 20-fold or more greater than the second receptor signaling potency. In some examples, the first receptor signaling potency is at least 50-fold or more greater than the second receptor signaling potency. In some examples, the first receptor signaling potency is at least 100-fold or more greater than the second receptor signaling potency. In some examples, the first receptor signaling potency is at least 500-fold or more greater than the second receptor signaling potency. In some instances, the first receptor signaling potency is at least 1000 times greater or greater than the second receptor signaling potency.In some instances, the first receptor signaling potency of the modified IL-2 polypeptide is higher than the receptor signaling potency of the wild-type IL-2 polypeptide for IL-2Rβγ, and the second receptor signaling potency of the modified IL-2 polypeptide is lower than the receptor signaling potency of the wild-type IL-2 polypeptide for IL-2Rαβγ. In some instances, both receptor signaling potencies are lower than their respective potencies in the wild-type IL-2 polypeptide. In other instances, both receptor signaling potencies are higher than their respective potencies in the wild-type IL-2 polypeptide.

[0092] In some embodiments, the IL-2 conjugate reduces adverse toxic events in a subject administered the IL-2 conjugate. Exemplary adverse toxic events include eosinophilia, capillary leak, and vascular leak syndrome (VLS). In some examples, the IL-2 conjugate reduces the occurrence of adverse toxic events in a subject by about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or about 100% compared to a second subject administered wild-type IL-2 or aldesleukin. In some examples, the IL-2 conjugate reduces the severity of a toxic adverse event in a subject by about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or about 100% compared to a second subject administered wild-type IL-2 or aldesleukin.

[0093] In some cases, the toxic adverse event is eosinophilia.In some cases, the IL-2 conjugate reduces the occurrence of eosinophilia in the subject by about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99% or about 100% compared to the second subject administered wild-type IL-2 or aldesleukin.In some cases, the IL-2 conjugate reduces the severity of eosinophilia in the subject by about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99% or about 100% compared to the second subject administered wild-type IL-2 or aldesleukin.

[0094] In some cases, the toxic adverse event is capillary leakage.In some cases, the IL-2 conjugate reduces the occurrence of capillary leakage in the subject by about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99% or about 100% compared to the second subject administered with wild-type IL-2 or aldesleukin.In some cases, the IL-2 conjugate reduces the severity of capillary leakage in the subject by about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99% or about 100% compared to the second subject administered with wild-type IL-2 or aldesleukin.

[0095] In some instances, the toxic adverse event is VLS. In some instances, the IL-2 conjugate reduces the occurrence of VLS in the subject by about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or about 100% compared to a second subject administered wild-type IL-2 or aldesleukin. In some instances, the IL-2 conjugate reduces the severity of VLS in the subject by about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or about 100% compared to a second subject administered wild-type IL-2 or aldesleukin.

[0096] In some embodiments, the IL-2 conjugate comprises a plasma half-life of greater than 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 18 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, or more. In some embodiments, the IL-2 conjugate comprises a plasma half-life of greater than 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, or more. In some embodiments, the IL-2 conjugate comprises a plasma half-life of greater than 1 hour. In some embodiments, the IL-2 conjugate comprises a plasma half-life of greater than 2 hours. In some embodiments, the IL-2 conjugate comprises a plasma half-life of greater than 3 hours. In some embodiments, the IL-2 conjugate comprises a plasma half-life of greater than 4 hours. In some embodiments, the IL-2 conjugate comprises a plasma half-life of greater than 5 hours. In some embodiments, the IL-2 conjugate comprises a plasma half-life of greater than 6 hours. In some embodiments, the IL-2 conjugate comprises a plasma half-life of greater than 7 hours. In some embodiments, the IL-2 conjugate comprises a plasma half-life of greater than 8 hours. In some embodiments, the IL-2 conjugate comprises a plasma half-life of greater than 9 hours. In some embodiments, the IL-2 conjugate comprises a plasma half-life of greater than 10 hours. In some embodiments, the IL-2 conjugate comprises a plasma half-life of greater than 12 hours. In some embodiments, the IL-2 conjugate comprises a plasma half-life of greater than 18 hours. In some embodiments, the IL-2 conjugate comprises a plasma half-life of greater than 24 hours.

[0097] In some embodiments, the IL-2 conjugate comprises a plasma half-life of at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, or more. In some embodiments, the IL-2 conjugate comprises a plasma half-life of at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, or more. In some embodiments, the IL-2 conjugate comprises a plasma half-life of at least 1 hour. In some embodiments, the IL-2 conjugate comprises a plasma half-life of at least 2 hours. In some embodiments, the IL-2 conjugate comprises a plasma half-life of at least 3 hours. In some embodiments, the IL-2 conjugate comprises a plasma half-life of at least 4 hours. In some embodiments, the IL-2 conjugate comprises a plasma half-life of at least 5 hours. In some embodiments, the IL-2 conjugate comprises a plasma half-life of at least 6 hours. In some embodiments, the IL-2 conjugate comprises a plasma half-life of at least 7 hours. In some embodiments, the IL-2 conjugate comprises a plasma half-life of at least 8 hours. In some embodiments, the IL-2 conjugate comprises a plasma half-life of at least 9 hours. In some embodiments, the IL-2 conjugate comprises a plasma half-life of at least 10 hours. In some embodiments, the IL-2 conjugate comprises a plasma half-life of at least 12 hours. In some embodiments, the IL-2 conjugate comprises a plasma half-life of at least 18 hours. In some embodiments, the IL-2 conjugate comprises a plasma half-life of at least 24 hours.

[0098] In some embodiments, the IL-2 conjugate comprises a plasma half-life of about 1 hour to about 7 days, about 12 hours to about 7 days, about 18 hours to about 7 days, about 24 hours to about 7 days, about 1 hour to about 5 days, about 12 hours to about 5 days, about 24 hours to about 5 days, about 2 days to about 5 days, or about 2 days to about 3 days.

[0099] In some embodiments, the IL-2 conjugate is incubated for about 1 hour to about 18 hours, for about 1 hour to about 18 hours. These include plasma half-lives of about 12 hours, about 2 hours to about 10 hours, about 2 hours to about 8 hours, about 4 hours to about 18 hours, about 4 hours to about 12 hours, about 4 hours to about 10 hours, about 4 hours to about 8 hours, about 6 hours to about 18 hours, about 6 hours to about 12 hours, about 6 hours to about 10 hours, about 6 hours to about 8 hours, about 8 hours to about 18 hours, about 8 hours to about 12 hours, or about 8 hours to about 10 hours.

[0100] In some embodiments, the IL-2 conjugate comprises a plasma half-life that allows proliferation and / or expansion of CD4+ helper cells, CD8+ effector naive and memory T cells, NK cells, NKT cells, or combinations thereof, but does not exert deleterious effects such as apoptosis.

[0101] In some embodiments, the IL-2 conjugate comprises an increased plasma half-life, e.g., by at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, or more, compared to wild-type IL-2. In some embodiments, the IL-2 conjugate comprises an increased plasma half-life, e.g., by at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, or more, compared to wild-type IL-2.

[0102] In some embodiments, the IL-2 conjugate comprises an extended plasma half-life of, for example, about 1 hour to about 18 hours, about 1 hour to about 12 hours, about 2 hours to about 10 hours, about 2 hours to about 8 hours, about 4 hours to about 18 hours, about 4 hours to about 12 hours, about 4 hours to about 10 hours, about 4 hours to about 8 hours, about 6 hours to about 18 hours, about 6 hours to about 12 hours, about 6 hours to about 10 hours, about 6 hours to about 8 hours, about 8 hours to about 18 hours, about 8 hours to about 12 hours, or about 8 hours to about 10 hours, compared to wild-type IL-2.

[0103] In some embodiments, the IL-2 conjugate comprises an extended plasma half-life of at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, or more, compared to, for example, aldesleukin. In some embodiments, the IL-2 conjugate comprises an extended plasma half-life of at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, or more, compared to, for example, aldesleukin.

[0104] In some embodiments, the IL-2 conjugate comprises an extended plasma half-life of, for example, about 1 hour to about 18 hours, about 1 hour to about 12 hours, about 2 hours to about 10 hours, about 2 hours to about 8 hours, about 4 hours to about 18 hours, about 4 hours to about 12 hours, about 4 hours to about 10 hours, about 4 hours to about 8 hours, about 6 hours to about 18 hours, about 6 hours to about 12 hours, about 6 hours to about 10 hours, about 6 hours to about 8 hours, about 8 hours to about 18 hours, about 8 hours to about 12 hours, or about 8 hours to about 10 hours, compared to aldesleukin.

[0105] In some embodiments, the IL-2 conjugate comprises an extended plasma half-life and has reduced toxicity. In some examples, the IL-2 conjugate comprises an extended plasma half-life of at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, or more, and has reduced toxicity. In some examples, the IL-2 conjugate comprises an extended plasma half-life of at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, or more, and has reduced toxicity. In some examples, the IL-2 conjugate comprises an extended plasma half-life of about 1 hour to about 18 hours, about 1 hour to about 12 hours, about 2 hours to about 10 hours, about 2 hours to about 8 hours, about 4 hours to about 18 hours, about 4 hours to about 12 hours, about 4 hours to about 10 hours, about 4 hours to about 8 hours, about 6 hours to about 18 hours, about 6 hours to about 12 hours, about 6 hours to about 10 hours, about 6 hours to about 8 hours, about 8 hours to about 18 hours, about 8 hours to about 12 hours, or about 8 hours to about 10 hours, and has reduced toxicity. In some cases, the reduced toxicity is at least 1-fold, 2-fold, 3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold, 10-fold, 20-fold, 30-fold, 50-fold, 100-fold, or more, compared to wild-type IL2. In some cases, the reduced toxicity is at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 200%, 300%, 400%, 500% or more compared to wild-type IL-2.

[0106] In some embodiments, the IL-2 conjugate comprises an extended plasma half-life and has reduced toxicity. In some examples, the IL-2 conjugate comprises an extended plasma half-life of at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, or more, and has reduced toxicity. In some examples, the IL-2 conjugate comprises an extended plasma half-life of at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, or more, and has reduced toxicity. In some examples, the IL-2 conjugate comprises an extended plasma half-life of about 1 hour to about 18 hours, about 1 hour to about 12 hours, about 2 hours to about 10 hours, about 2 hours to about 8 hours, about 4 hours to about 18 hours, about 4 hours to about 12 hours, about 4 hours to about 10 hours, about 4 hours to about 8 hours, about 6 hours to about 18 hours, about 6 hours to about 12 hours, about 6 hours to about 10 hours, about 6 hours to about 8 hours, about 8 hours to about 18 hours, about 8 hours to about 12 hours, or about 8 hours to about 10 hours, and exhibits reduced toxicity. In some cases, the reduced toxicity is at least 1-fold, 2-fold, 3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold, 10-fold, 20-fold, 30-fold, 50-fold, 100-fold, or more, compared to aldesleukin. In some cases, the reduced toxicity is at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 200%, 300%, 400%, 500% or more compared to aldesleukin.

[0107] In some embodiments, the IL-2 conjugate comprises a conjugating moiety, and the size (e.g., volume or length) of the conjugating moiety increases plasma stability but does not decrease potency. In some examples, the size of the conjugating moiety extends plasma half-life by at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, or more. In some examples, the size of the conjugating moiety extends plasma half-life by at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, or more. In some examples, the size of the conjugated moiety increases the plasma half-life by about 1 hour to about 18 hours, about 1 hour to about 12 hours, about 2 hours to about 10 hours, about 2 hours to about 8 hours, about 4 hours to about 18 hours, about 4 hours to about 12 hours, about 4 hours to about 10 hours, about 4 hours to about 8 hours, about 6 hours to about 18 hours, about 6 hours to about 12 hours, about 6 hours to about 10 hours, about 6 hours to about 8 hours, about 8 hours to about 18 hours, about 8 hours to about 12 hours, or about 8 hours to about 10 hours. In some examples, the size of the conjugated moiety reduces potency by less than 5%, 4%, 3%, 2%, 1%, or more compared to aldesleukin.

[0108] In some embodiments, the IL-2 conjugate comprises a conjugating moiety, and the size (e.g., volume or length) of the conjugating moiety increases plasma stability and potency. In some examples, the size of the conjugating moiety increases plasma half-life by at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, or more. In some examples, the size of the conjugating moiety increases plasma half-life by at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, or more. In some examples, the size of the conjugated moiety increases the plasma half-life by about 1 hour to about 18 hours, about 1 hour to about 12 hours, about 2 hours to about 10 hours, about 2 hours to about 8 hours, about 4 hours to about 18 hours, about 4 hours to about 12 hours, about 4 hours to about 10 hours, about 4 hours to about 8 hours, about 6 hours to about 18 hours, about 6 hours to about 12 hours, about 6 hours to about 10 hours, about 6 hours to about 8 hours, about 8 hours to about 18 hours, about 8 hours to about 12 hours, or about 8 hours to about 10 hours. In some examples, the size of the conjugated moiety further increases potency by more than 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 200% or more compared to aldesleukin.

[0109] In some embodiments, described herein are IL-2 conjugates that include a non-natural amino acid covalently attached to a conjugating moiety, wherein the non-natural amino acid is located in region 35-107, which region 35-107 corresponds to residues K35-Y107 of SEQ ID NO:1.

[0110] In some embodiments, described herein are interleukin-2 beta gamma receptor (IL-2Rβγ) binding proteins, wherein the binding affinity of the binding protein to interleukin-2 alpha receptor (IL-2Rα) is less than that of wild-type human IL-2 (hIL-2), and wherein the binding affinity of the binding protein to interleukin-2 alpha receptor (IL-2Rα) is less than that of wild-type human IL-2 (hIL-2). In some embodiments, described herein are interleukin-2 beta gamma receptor (IL-2Rβγ) binding proteins, wherein the binding affinity of the binding protein to interleukin-2 alpha receptor (IL-2Rα) is less than that of wild-type human IL-2 (hIL-2), and wherein the binding protein comprises at least one unnatural amino acid. In some examples, the binding protein is a modified IL-2 polypeptide or a functionally active fragment thereof, wherein the modified IL-2 polypeptide comprises at least one unnatural amino acid. In some examples, the at least one unnatural amino acid is located in region 35-107, which corresponds to residues K35-Y107 of SEQ ID NO:1.

[0111] In some embodiments, described herein is an IL-2 / IL-2Rβγ complex comprising a modified IL-2 polypeptide and IL-2Rβγ comprising a mutation, wherein the modified IL-2 polypeptide has a reduced binding affinity to IL-2Rα, the reduced binding affinity being compared to the binding affinity between the wild-type IL-2 polypeptide and IL-2Rα. In some examples, the modified IL-2 polypeptide further comprises a conjugation moiety covalently attached to the site of the mutation. In some examples, the site of the mutation comprises an amino acid mutated to a natural amino acid. In some cases, the site of the mutation comprises an amino acid mutated to a cysteine ​​residue. In other cases, the site of the mutation comprises an amino acid mutated to a lysine residue.

[0112] In some embodiments, described herein is an IL-2 / IL-2Rβγ complex comprising a modified IL-2 polypeptide comprising an unnatural amino acid and IL-2Rβγ, wherein the modified IL-2 polypeptide has a reduced binding affinity to IL-2Rα, where the reduced binding affinity is compared to the binding affinity between a wild-type IL-2 polypeptide and IL-2Rα. In some examples, the modified IL-2 polypeptide further comprises a conjugating moiety covalently attached to the unnatural amino acid.

[0113] In some embodiments, described herein is an IL-2 / IL-2Rβγ complex comprising a modified IL-2 polypeptide comprising an unnatural amino acid and IL-2Rβγ, wherein the modified IL-2 polypeptide has a reduced receptor signaling potency to IL-2Rα, wherein the reduced receptor signaling potency is compared to the receptor signaling potency between a wild-type IL-2 polypeptide and IL-2Rα. In some examples, the modified IL-2 polypeptide further comprises a conjugating moiety covalently attached to the unnatural amino acid.

[0114] In some embodiments, described herein are activators of CD4+ helper cells, CD8+ effector naive and memory T cells, natural killer (NK) cells, or natural killer T (NKT) cells, which selectively expand CD4+ helper cells, CD8+ effector naive and memory T cells, NK cells, NKT cells, or combinations thereof in a cell population, wherein the activator comprises a modified interleukin-2 (IL-2) polypeptide comprising at least one mutation. In some examples, the mutation is a change to a naturally occurring amino acid. In other examples, the mutation is a change to a non-naturally occurring amino acid. In some embodiments, described herein are activators of CD4+ helper cells, CD8+ effector naive and memory T cells, natural killer (NK) cells, or natural killer T (NKT) cells, which selectively expand CD4+ helper cells, CD8+ effector naive and memory T cells, NK cells, NKT cells, or a combination thereof in a cell population, wherein the activator comprises a modified interleukin-2 (IL-2) polypeptide comprising at least one unnatural amino acid. In some examples, the activator, when contacted with the CD3+ cell population, expands CD4+ T regulatory (Treg) cells by less than 20%, 15%, 10%, 5%, 1%, or 0.1% compared to the expansion of CD4+ Treg cells in a CD3+ cell population contacted with a wild-type IL-2 polypeptide. In some examples, the activator does not expand Treg cells in the cell population. In some examples, the cell population is an in vivo cell population. In some examples, the cell population is an in vitro cell population. In some examples, the cell population is an ex vivo cell population.

[0115] In some examples, also described herein are methods for expanding a CD4+ helper cell, CD8+ effector naive and memory T cell, natural killer (NK) cell, or natural killer T (NKT) cell population, the methods comprising contacting the cell population with a therapeutically effective amount of a CD4+ helper cell, CD8+ effector naive and memory T cell, natural killer (NK) cell, or natural killer T (NKT) cell activator, wherein the activator comprises a modified interleukin-2 (IL-2) polypeptide comprising at least one mutation, thereby expanding the CD4+ helper cell, CD8+ effector naive and memory T cell, natural killer (NK) cell, or natural killer T (NKT) cell population. In some examples, the mutation is a change to a naturally occurring amino acid. In other examples, the mutation is a change to a non-naturally occurring amino acid. In some examples, also described herein are methods of expanding a CD4+ helper cell, CD8+ effector naive and memory T cell, natural killer (NK) cell, or natural killer T (NKT) cell population, the methods comprising contacting the cell population with a therapeutically effective amount of a CD4+ helper cell, CD8+ effector naive and memory T cell, natural killer (NK) cell, or natural killer T (NKT) cell activator, wherein the activator comprises a modified interleukin-2 (IL-2) polypeptide comprising at least one unnatural amino acid, thereby expanding the CD4+ helper cell, CD8+ effector naive and memory T cell, natural killer (NK) cell, or natural killer T (NKT) cell population.

[0116] In some embodiments, the modified IL-2 polypeptide comprising a mutation at K35, corresponding to residue position 35 of SEQ ID NO:1, comprises a conjugation moiety comprising a PEG having a molecular weight of about 2,000 to 50,000 Da. In some embodiments, the molecular weight comprises 5,000 Da. In some embodiments, the molecular weight comprises 10,000 Da. In some embodiments, the molecular weight comprises 15,000 Da. In some embodiments, the molecular weight comprises 20,000 Da. In some embodiments, the molecular weight comprises 25,000 Da. In some embodiments, the molecular weight comprises 30,000 Da. In some embodiments, the molecular weight comprises 35,000 Da. In some embodiments, the molecular weight comprises 40,000 Da. In some embodiments, the molecular weight comprises 45,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 55,000 Da. In some embodiments, the molecular weight comprises 60,000 Da. In some embodiments, the molecular weight of the PEG at least partially determines the in vivo plasma half-life of the modified IL-2 polypeptide. In some examples, the PEG corresponds to a longer in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a smaller PEG. In some examples, the PEG corresponds to a shorter in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a larger PEG. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the receptor signaling efficacy of the modified IL-2 polypeptide to the IL-2βγ or IL-2αβγ signaling complex. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the desired reduced binding of the modified IL-2 polypeptide to IL-2Rα or maintained binding to the IL-2Rβγ signaling complex, where the reduced binding to IL-2Rα is compared to the binding between the wild-type IL-2 polypeptide and IL-2Rα. In some embodiments, the molecular weight of PEG does not affect the formation of the modified IL-2 polypeptide / IL-2Rβγ complex, and the reduced binding to IL-2Rα is compared to the binding between wild-type IL-2 polypeptide and IL-2Rα.

[0117] In some embodiments, the modified IL-2 polypeptide comprising a mutation at residue T37, corresponding to position 37 of SEQ ID NO: 1, comprises a conjugation moiety comprising a PEG having a molecular weight of about 2,000 to 50,000 Da. In some embodiments, the molecular weight comprises 5,000 Da. In some embodiments, the molecular weight comprises 10,000 Da. In some embodiments, the molecular weight comprises 15,000 Da. In some embodiments, the molecular weight comprises 20,000 Da. In some embodiments, the molecular weight comprises 25,000 Da. In some embodiments, the molecular weight comprises 30,000 Da. In some embodiments, the molecular weight comprises 35,000 Da. In some embodiments, the molecular weight comprises 40,000 Da. In some embodiments, the molecular weight comprises 45,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 55,000 Da. In some embodiments, the molecular weight comprises 60,000 Da. In some embodiments, the molecular weight of the PEG at least partially determines the in vivo plasma half-life of the modified IL-2 polypeptide. In some examples, the PEG corresponds to a longer in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a smaller PEG. In some examples, the PEG corresponds to a shorter in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a larger PEG. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the receptor signaling efficacy of the modified IL-2 polypeptide to the IL-2βγ or IL-2αβγ signaling complex. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the desired reduced binding of the modified IL-2 polypeptide to IL-2Rα or maintained binding to the IL-2Rβγ signaling complex, where the reduced binding to IL-2Rα is compared to the binding between the wild-type IL-2 polypeptide and IL-2Rα. In some embodiments, the molecular weight of PEG does not affect the formation of the modified IL-2 polypeptide / IL-2Rβγ complex, and the reduced binding to IL-2Rα is compared to the binding between wild-type IL-2 polypeptide and IL-2Rα.

[0118] In some examples, the conjugation moiety is located at amino acid positions A1, P2, T3, S4, S5, S6, T7, K8, K9, Q11, L12, E15, H16, L18, L19, D20, Q22, M23, N26, G27, N29, N30, Y31, K32, K35, T37, M46, K47, K48, A50, T51, E52, K53, H55, Q57, E60, E67, N71, Q74, S75, K76, N77, F78, H79, R81, P82, R83, D84, and linked to an amino acid residue selected from S87, N88, N89, V91, I92, L94, E95, K97, G98, S99, E100, T101, T102, F103, M104, C105, E106, Y107, A108, D109, E110, T111, A112, T113, E116, N119, R120, T123, A125, Q126, S127, S130, T131, L132, and T133, where the numbering of the amino acid residues corresponds to SEQ ID NO: 1. In some examples, the amino acid positions are selected from K8, K9, Q11, L12, E15, H16, L18, L19, D20, Q22, M23, N26, R81, D84, S87, N88, V91, I92, L94, E95, E116, N119, R120, T123, A125, Q126, S127, S130, T131, L132, and T133. In some examples, the amino acid positions are selected from A1, P2, T3, S4, S5, S6, T7, G27, N29, N30, Y31, K32, K35, T37, M46, K47, K48, A50, T51, E52, K53, H55, Q57, E60, E67, N71, Q74, S75, K76, N77, F78, H79, P82, R83, N89, K97, G98, S99, E100, T101, T102, F103, M104, C105, E106, Y107, A108, D109, E110, T111, A112, and T113. In some examples, the amino acid positions are selected from K8, K9, L12, E15, H16, L19, D20, Q22, M23, N26, D84, N88, E95, and Q126. In some examples, the amino acid positions are selected from K8, K9, and H16. In some examples, the amino acid positions are selected from Q22, N26, N88, and Q126.In some examples, the amino acid position is selected from E15, D20, D84, and E95. In some examples, the amino acid position is selected from L12, L19, and M23. In some examples, the amino acid position is selected from Q22 and N26. In some cases, the amino acid position is at K8. In some cases, the amino acid position is at K9. In some cases, the amino acid position is at Q11. In some cases, the amino acid position is at L12. In some cases, the amino acid position is at E15. In some cases, the amino acid position is at H16. In some cases, the amino acid position is at L18. In some cases, the amino acid position is at L19. In some cases, the amino acid position is at D20. In some cases, the amino acid position is at Q22. In some cases, the amino acid position is at M23. In some cases, the amino acid position is at N26. In some cases, the amino acid position is at R81. In some cases, the amino acid position is at D84. In some cases, the amino acid position is at S87. In some cases, the amino acid position is at N88. In some cases, the amino acid position is at V91. In some cases, the amino acid position is at I92. In some cases, the amino acid position is at L94. In some cases, the amino acid position is at E95. In some cases, the amino acid position is at E116. In some cases, the amino acid position is at N119. In some cases, the amino acid position is at R120. In some cases, the amino acid position is at T123. In some cases, the amino acid position is at A125. In some cases, the amino acid position is at Q126. In some cases, the amino acid position is at S127. In some cases, the amino acid position is at S130. In some cases, the amino acid position is at T131. In some cases, the amino acid position is at L132. In some cases, the amino acid position is at T133.

[0119] In some examples, the IL-2 conjugate further comprises an additional mutation. In such cases, the amino acid is conjugated to an additional conjugation moiety for increased serum half-life, stability, or a combination thereof. Alternatively, the amino acid is first mutated to a natural amino acid, such as lysine, cysteine, histidine, arginine, aspartic acid, glutamic acid, serine, threonine, or tyrosine; or to a non-natural amino acid, before being attached to the additional conjugation moiety.

[0120] In some embodiments, the IL-2 conjugate has reduced binding affinity to the IL-2 receptor beta (IL-2Rβ) subunit, the IL-2 receptor gamma (IL-2Rγ) subunit, or a combination thereof, of the IL-2Rαβγ complex, compared to a wild-type IL-2 polypeptide. In some examples, the reduced affinity of the IL-2 conjugate to the IL-2 receptor beta (IL-2Rβ) subunit, the IL-2 receptor gamma (IL-2Rγ) subunit, or a combination thereof, compared to a wild-type IL-2 polypeptide, is about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or greater than 99%. In some cases, the reduced affinity is about 10%. In some cases, the reduced affinity is about 20%. In some cases, the reduced affinity is about 40%. In some cases, the reduced affinity is about 50%. In some cases, the reduced affinity is about 60%. In some cases, the reduced affinity is about 80%. In some cases, the reduced affinity is about 90%. In some cases, the reduced affinity is about 99%. In some cases, the reduced affinity is greater than about 99%. In some cases, the reduced affinity is about 80%. In some cases, the reduced affinity is about 100%.

[0121] In some embodiments, the reduced binding affinity of the IL-2 conjugate to the IL-2 receptor beta (IL-2Rβ) subunit, the IL-2 receptor gamma (IL-2Rγ) subunit, or a combination thereof, compared to a wild-type IL-2 polypeptide is about 1-fold, 2-fold, 3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold, 10-fold, 30-fold, 50-fold, 100-fold, 200-fold, 300-fold, 400-fold, 500-fold, 1,000-fold, or more. In some embodiments, the reduced affinity is about 1-fold. In some cases, the reduced affinity is about 2-fold. In some cases, the reduced affinity is about 4-fold. In some cases, the reduced affinity is about 5-fold. In some cases, the reduced affinity is about 6-fold. In some cases, the reduced affinity is about 8-fold. In some cases, the reduced affinity is about 10-fold. In some cases, the reduced affinity is about 30-fold. In some cases, the reduced affinity is about 50-fold. In some cases, the reduced affinity is about 100-fold. In some cases, the reduced affinity is about 300-fold. In some cases, the reduced affinity is about 500-fold. In some cases, the reduced affinity is about 1000-fold. In some cases, the reduced affinity is more than 1,000-fold.

[0122] In some embodiments, the IL-2 conjugate has reduced IL-2Rγ subunit recruitment to the IL-2 / IL-2Rβ complex. Optionally, the reduced recruitment is compared to IL-2Rγ subunit recruitment by an equivalent IL-2 polypeptide (e.g., a wild-type IL-2 polypeptide) without the unnatural amino acid. Optionally, the reduction in IL-2Rγ subunit recruitment is about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or greater than 99% compared to an equivalent IL-2 polypeptide without the unnatural amino acid modification. Optionally, the reduction in IL-2Rγ subunit recruitment is about 10%. Optionally, the reduction in IL-2Rγ subunit recruitment is about 20%. Optionally, the reduction in IL-2Rγ subunit recruitment is about 40%. Optionally, the reduction in IL-2Rγ subunit recruitment is about 50%. In some instances, the reduction in IL-2Rγ subunit recruitment is about 60%. In some instances, the reduction in IL-2Rγ subunit recruitment is about 70%. In some instances, the reduction in IL-2Rγ subunit recruitment is about 80%. In some instances, the reduction in IL-2Rγ subunit recruitment is about 90%. In some instances, the reduction in IL-2Rγ subunit recruitment is about 99%. In some instances, the reduction in IL-2Rγ subunit recruitment is greater than 99%. In some instances, the reduction in IL-2Rγ subunit recruitment is about 100%. In some examples, the IL-2 conjugate further has increased IL-2Rα subunit recruitment.

[0123] In some embodiments, the reduction in IL-2Rγ subunit recruitment is about 1-fold, 2-fold, 3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold, 10-fold, 30-fold, 50-fold, 100-fold, 200-fold, 300-fold, 400-fold, 500-fold, 1,000-fold, or more, compared to an equivalent IL-2 polypeptide (e.g., a wild-type IL-2 polypeptide) without the non-natural amino acid modification. In some embodiments, the reduction in IL-2Rγ subunit recruitment is about 1-fold. In some cases, the reduction in IL-2Rγ subunit recruitment is about 2-fold. In some cases, the reduction in IL-2Rγ subunit recruitment is about 4-fold. In some cases, the reduction in IL-2Rγ subunit recruitment is about 5-fold. In some cases, the reduction in IL-2Rγ subunit recruitment is about 6-fold. In some cases, the reduction in IL-2Rγ subunit recruitment is about 8-fold. In some instances, the reduction in IL-2Rγ subunit recruitment is about 10-fold. In some instances, the reduction in IL-2Rγ subunit recruitment is about 30-fold. In some instances, the reduction in IL-2Rγ subunit recruitment is about 50-fold. In some instances, the reduction in IL-2Rγ subunit recruitment is about 100-fold. In some instances, the reduction in IL-2Rγ subunit recruitment is about 300-fold. In some instances, the reduction in IL-2Rγ subunit recruitment is about 500-fold. In some instances, the reduction in IL-2Rγ subunit recruitment is about 1000-fold. In some instances, the reduction in IL-2Rγ subunit recruitment is more than 1,000-fold. In some instances, the IL-2 conjugate further has increased IL-2Rα subunit recruitment.

[0124] In some embodiments, the IL-2 conjugate has increased IL-2R α subunit recruitment to the IL-2 polypeptide. In some embodiments, the decreased recruitment is compared to IL-2R α subunit recruitment by an equivalent IL-2 polypeptide (e.g., a wild-type IL-2 polypeptide) without the unnatural amino acid. In some cases, the increase in IL-2R α subunit recruitment is about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or greater than 99% compared to an equivalent IL-2 polypeptide without the unnatural amino acid modification. In some cases, the increase in IL-2R α subunit recruitment is about 10%. In some cases, the increase in IL-2R α subunit recruitment is about 20%. In some cases, the increase in IL-2R α subunit recruitment is about 40%. In some cases, the increase in IL-2R α subunit recruitment is about 50%. In some instances, the increase in IL-2Rα subunit recruitment is about 60%. In some instances, the increase in IL-2Rα subunit recruitment is about 70%. In some instances, the increase in IL-2Rα subunit recruitment is about 80%. In some instances, the increase in IL-2Rα subunit recruitment is about 90%. In some instances, the increase in IL-2Rα subunit recruitment is about 99%. In some instances, the increase in IL-2Rα subunit recruitment is greater than 99%. In some instances, the increase in IL-2Rα subunit recruitment is about 100%. In some examples, the IL-2 conjugate further has reduced recruitment of the IL-2Rβ subunit and / or the IL-2Rγ subunit.

[0125] In some embodiments, the increase in IL-2R α subunit recruitment is about 1-fold, 2-fold, 3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold, 10-fold, 30-fold, 50-fold, 100-fold, 200-fold, 300-fold, 400-fold, 500-fold, 1,000-fold, or more, compared to an equivalent IL-2 polypeptide (e.g., a wild-type IL-2 polypeptide) without the non-natural amino acid modification. In some embodiments, the increase in IL-2R α subunit recruitment is about 1-fold. In some cases, the increase in IL-2R α subunit recruitment is about 2-fold. In some cases, the increase in IL-2R α subunit recruitment is about 4-fold. In some cases, the increase in IL-2R α subunit recruitment is about 5-fold. In some cases, the increase in IL-2R α subunit recruitment is about 6-fold. In some cases, the increase in IL-2R α subunit recruitment is about 8-fold. In some instances, the increase in IL-2Rα subunit recruitment is about 10-fold. In some instances, the increase in IL-2Rα subunit recruitment is about 30-fold. In some instances, the increase in IL-2Rα subunit recruitment is about 50-fold. In some instances, the increase in IL-2Rα subunit recruitment is about 100-fold. In some instances, the increase in IL-2Rα subunit recruitment is about 300-fold. In some instances, the increase in IL-2Rα subunit recruitment is about 500-fold. In some instances, the increase in IL-2Rα subunit recruitment is about 1000-fold. In some instances, the increase in IL-2Rα subunit recruitment is more than 1,000-fold. In some examples, the IL-2 conjugate further has reduced recruitment of the IL-2Rβ subunit and / or the IL-2Rγ subunit.

[0126] In some embodiments, the IL-2 polypeptides described herein have reduced receptor signaling potency for IL-2Rβγ. In some examples, the reduction in receptor signaling potency is about 1-fold, 2-fold, 3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold, 10-fold, 30-fold, 50-fold, 100-fold, 200-fold, 300-fold, 400-fold, 500-fold, 1000-fold, or more for IL-2Rβγ compared to wild-type IL-2 polypeptides. In some cases, the reduction in receptor signaling potency is about 2-fold. In some cases, the reduction in receptor signaling potency is about 5-fold. In some cases, the reduction in receptor signaling potency is about 10-fold. In some cases, the reduction in receptor signaling potency is about 20-fold. In some cases, the reduction in receptor signaling potency is about 30-fold. In some cases, the reduction in receptor signaling potency is about 40-fold. In some cases, the reduction in receptor signaling potency is about 50-fold. In some cases, the reduction in receptor signaling potency is about 100-fold. In some cases, the reduction in receptor signaling potency is about 200-fold. In some cases, the reduction in receptor signaling potency is about 300-fold. In some cases, the reduction in receptor signaling potency is about 400-fold. In some cases, the reduction in receptor signaling potency is about 500-fold. In some cases, the reduction in receptor signaling potency is about 1000-fold.

[0127] In some examples, receptor signaling potency is measured by an EC50 value. In some cases, a decrease in receptor signaling potency is an increase in EC50. In some examples, the increase in EC50 is about 1-fold, 2-fold, 3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold, 10-fold, 30-fold, 50-fold, 100-fold, 200-fold, 300-fold, 400-fold, 500-fold, 1000-fold, or more, compared to a wild-type IL-2 polypeptide.

[0128] In some cases, receptor signaling potency is measured by an ED50 value. In some cases, a decrease in receptor signaling potency is an increase in ED50. In some cases, the increase in ED50 is about 1-fold, 2-fold, 3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold, 10-fold, 30-fold, 50-fold, 100-fold, 200-fold, 300-fold, 400-fold, 500-fold, 1000-fold, or more, compared to a wild-type IL-2 polypeptide.

[0129] In some embodiments, the IL-2 polypeptides described herein have an expanded therapeutic window compared to the therapeutic window of wild-type IL-2 polypeptides. In some examples, the expanded therapeutic window is due to reduced binding between the IL-2 polypeptide and interleukin-2 receptor βγ (IL-2Rβγ), reduced receptor signaling efficacy for IL-2Rβγ, reduced recruitment of the IL-2Rγ subunit to the IL-2 / IL-2Rβ complex, or increased recruitment of the IL-2Rα subunit to the IL-2 polypeptide. In some examples, the IL-2 polypeptides do not have impaired activation of the interleukin-2αβγ receptor (IL-2Rαβγ).

[0130] In some embodiments, the modified IL-2 polypeptide exhibits a first receptor signaling potency for the IL-2βγ signaling complex and a second receptor signaling potency for the IL-2αβγ signaling complex, wherein the difference between the first receptor signaling potency and the second receptor signaling potency is at least 1-fold. In some examples, the difference is at least 2-fold, 3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold, 10-fold, 20-fold, 30-fold, 40-fold, 50-fold, 60-fold, 70-fold, 80-fold, 90-fold, 100-fold, 200-fold, 300-fold, 400-fold, 500-fold, 1000-fold, or more. In some examples, the first receptor signaling potency is less than the second receptor signaling potency. In some examples, the first receptor signaling potency is at least 1-fold, 2-fold, 3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold, 10-fold, 20-fold, 30-fold, 50-fold, 100-fold, 500-fold, 1000-fold, or less than the second receptor signaling potency. In some cases, the modified IL-2 polypeptide has a lower receptor signaling potency for the IL-2βγ signaling complex than the second receptor signaling potency for the IL-2αβγ signaling complex. In some cases, the first receptor signaling potency of the modified IL-2 polypeptide is at least 1-fold lower than the receptor signaling potency of the wild-type IL-2 polypeptide. In some cases, the first receptor signaling potency of the modified IL-2 polypeptide is at least 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, 20-fold, 50-fold, 100-fold, 200-fold, or 500-fold lower than the receptor signaling potency of the wild-type IL-2 polypeptide. In some cases, the first receptor signaling potency and the second receptor signaling potency are both lower than the respective potencies of the wild-type IL-2 polypeptide, but the first receptor signaling potency is lower than the second receptor signaling potency. In some cases, the difference between the first receptor signaling potency and the second receptor signaling potency increases the therapeutic window for the modified IL-2 polypeptide.

[0131] In some examples, the conjugated moiety impairs or blocks the efficacy of receptor signaling of IL-2 with IL-2Rβγ or reduces recruitment of the IL-2Rγ subunit to the IL-2 / IL-2Rβ complex.

[0132] In some instances, modified IL-2 polypeptides with reduced receptor signaling potency for IL-2Rβγ can expand CD4+ T regulatory (Treg) cells.

[0133] In some embodiments, CD4+ Treg cell proliferation with the modified IL-2 / IL-2Rαβγ complex is comparable to or exceeds that of the wild-type IL-2 polypeptide.

[0134] In some embodiments, the IL-2 / IL-2Rαβγ complex induces the expansion of CD4+ Treg cells into a population sufficient to modulate the course of disease in animal models.

[0135] In some embodiments, described herein are interleukin-2 αβγ receptor (IL-2Rαβγ) binding proteins, wherein the binding protein has a receptor signaling potency for the interleukin-2 βγ receptor (IL-2Rβγ) that is less than that of wild-type human IL-2 (hIL-2), and wherein the binding protein comprises at least one unnatural amino acid. Optionally, the binding protein is a modified IL-2 polypeptide or a functionally active fragment thereof, wherein the modified IL-2 polypeptide comprises at least one unnatural amino acid.

[0136] In some embodiments, described herein are interleukin-2 αβγ receptor (IL-2Rαβγ) binding proteins, wherein the recruitment of the IL-2Rγ subunit to the IL-2 / IL-2Rβ complex by the binding protein is less than that of wild-type human IL-2 (hIL-2), and the binding protein comprises at least one unnatural amino acid. Optionally, the binding protein is a modified IL-2 polypeptide or a functionally active fragment thereof, wherein the modified IL-2 polypeptide comprises at least one unnatural amino acid.

[0137] In some embodiments, described herein are interleukin-2 αβγ receptor (IL-2Rαβγ) binding proteins, wherein the binding affinity of the binding protein to interleukin-2 βγ receptor (IL-2Rβγ) is less than that of wild-type human IL-2 (hIL-2), and the binding protein comprises at least one unnatural amino acid. In such cases, the binding protein is a modified IL-2 polypeptide or a functionally active fragment thereof, and the modified IL-2 polypeptide comprises at least one unnatural amino acid.

[0138] In some embodiments, described herein is an IL-2 / IL-2Rαβγ complex comprising a modified IL-2 polypeptide comprising an unnatural amino acid and IL-2Rαβγ, wherein the modified IL-2 polypeptide has reduced receptor signaling potency to IL-2Rβγ, wherein the reduced receptor signaling potency is compared to the binding affinity between a wild-type IL-2 polypeptide and IL-2Rβγ. Optionally, the modified IL-2 polypeptide further comprises a conjugating moiety covalently attached to the unnatural amino acid.

[0139] In some embodiments, described herein is an IL-2 / IL-2Rαβγ complex comprising a modified IL-2 polypeptide comprising an unnatural amino acid and IL-2Rαβγ, wherein the recruitment of the IL-2Rγ subunit to the IL-2 / IL-2Rβ complex by the modified IL-2 polypeptide is less than that of a wild-type IL-2 polypeptide. Optionally, the modified IL-2 polypeptide further comprises a conjugation moiety covalently attached to the unnatural amino acid.

[0140] In some embodiments, described herein is an IL-2 / IL-2Rαβγ complex comprising a modified IL-2 polypeptide comprising a non-natural amino acid and IL-2Rαβγ, wherein the modified IL-2 polypeptide has a reduced binding affinity to IL-2Rβγ, the reduced binding affinity being compared to the binding affinity between a wild-type IL-2 polypeptide and IL-2Rβγ. In some embodiments, described herein is an IL-2 / IL-2Rαβγ complex comprising a modified IL-2 polypeptide comprising a non-natural amino acid and IL-2Rαβγ, wherein recruitment of the IL-2Rγ subunit to the IL-2 / IL-2Rβ complex by the modified IL-2 polypeptide is less than that of a wild-type IL-2 polypeptide. In some examples, the modified IL-2 polypeptide further comprises a conjugating moiety covalently attached to the non-natural amino acid.

[0141] In some embodiments, described herein is a CD4+ Treg cell activator that selectively expands CD4+ Treg cells in a cell population, wherein the activator comprises a modified IL-2 polypeptide comprising at least one unnatural amino acid. In some examples, the activator, when contacted with the CD3+ cell population, expands CD8+ effector T cells and / or natural killer cells to less than 20%, 15%, 10%, 5%, 1%, or 0.1% in the CD3+ cell population compared to the expansion of CD8+ effector T cells and / or natural killer cells in the CD3+ cell population contacted with a wild-type IL-2 polypeptide. In some examples, the cell population is an in vivo cell population. In some examples, the cell population is an in vitro cell population. In some examples, the cell population is an ex vivo cell population.

[0142] In some embodiments, the modified IL-2 polypeptide comprising a mutation at residue K8, corresponding to position 8 of SEQ ID NO:3, comprises a conjugation moiety comprising a PEG having a molecular weight of about 2,000 to 60,000 Da. In some embodiments, the molecular weight comprises 5,000 Da. In some embodiments, the molecular weight comprises 10,000 Da. In some embodiments, the molecular weight comprises 15,000 Da. In some embodiments, the molecular weight comprises 20,000 Da. In some embodiments, the molecular weight comprises 25,000 Da. In some embodiments, the molecular weight comprises 30,000 Da. In some embodiments, the molecular weight comprises 35,000 Da. In some embodiments, the molecular weight comprises 40,000 Da. In some embodiments, the molecular weight comprises 45,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 55,000 Da. In some embodiments, the molecular weight comprises 60,000 Da. In some embodiments, the molecular weight of the PEG at least partially determines the in vivo plasma half-life of the modified IL-2 polypeptide. In some examples, the PEG corresponds to a longer in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a smaller PEG. In some examples, the PEG corresponds to a shorter in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a larger PEG. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the receptor signaling efficacy of the modified IL-2 polypeptide to the IL-2βγ or IL-2αβγ signaling complex. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the desired reduced binding of the modified IL-2 polypeptide to IL-2Rα or maintained binding to the IL-2Rβγ signaling complex, where the reduced binding to IL-2Rα is compared to the binding between the wild-type IL-2 polypeptide and IL-2Rα. In some embodiments, the molecular weight of PEG does not affect the formation of the modified IL-2 polypeptide / IL-2Rβγ complex, and the reduced binding to IL-2Rα is compared to the binding between wild-type IL-2 polypeptide and IL-2Rα.

[0143] In some embodiments, the modified IL-2 polypeptide comprising a mutation at residue H15, corresponding to position 15 of SEQ ID NO:3, comprises a conjugation moiety comprising a PEG having a molecular weight of about 2,000 to 60,000 Da. In some embodiments, the molecular weight comprises 5,000 Da. In some embodiments, the molecular weight comprises 10,000 Da. In some embodiments, the molecular weight comprises 15,000 Da. In some embodiments, the molecular weight comprises 20,000 Da. In some embodiments, the molecular weight comprises 25,000 Da. In some embodiments, the molecular weight comprises 30,000 Da. In some embodiments, the molecular weight comprises 35,000 Da. In some embodiments, the molecular weight comprises 40,000 Da. In some embodiments, the molecular weight comprises 45,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 55,000 Da. In some embodiments, the molecular weight comprises 60,000 Da. In some embodiments, the molecular weight of the PEG at least partially determines the in vivo plasma half-life of the modified IL-2 polypeptide. In some examples, the PEG corresponds to a longer in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a smaller PEG. In some examples, the PEG corresponds to a shorter in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a larger PEG. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the receptor signaling efficacy of the modified IL-2 polypeptide to the IL-2βγ or IL-2αβγ signaling complex. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the desired reduced binding of the modified IL-2 polypeptide to IL-2Rα or maintained binding to the IL-2Rβγ signaling complex, where the reduced binding to IL-2Rα is compared to the binding between the wild-type IL-2 polypeptide and IL-2Rα. In some embodiments, the molecular weight of PEG does not affect the formation of the modified IL-2 polypeptide / IL-2Rβγ complex, and the reduced binding to IL-2Rα is compared to the binding between wild-type IL-2 polypeptide and IL-2Rα.

[0144] In some embodiments, the modified IL-2 polypeptide comprising a mutation at residue L18, corresponding to position 18 of SEQ ID NO:3, comprises a conjugation moiety comprising a PEG having a molecular weight of about 2,000 to 60,000 Da. In some embodiments, the molecular weight comprises 5,000 Da. In some embodiments, the molecular weight comprises 10,000 Da. In some embodiments, the molecular weight comprises 15,000 Da. In some embodiments, the molecular weight comprises 20,000 Da. In some embodiments, the molecular weight comprises 25,000 Da. In some embodiments, the molecular weight comprises 30,000 Da. In some embodiments, the molecular weight comprises 35,000 Da. In some embodiments, the molecular weight comprises 40,000 Da. In some embodiments, the molecular weight comprises 45,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 55,000 Da. In some embodiments, the molecular weight comprises 60,000 Da. In some embodiments, the molecular weight of the PEG at least partially determines the in vivo plasma half-life of the modified IL-2 polypeptide. In some examples, the PEG corresponds to a longer in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a smaller PEG. In some examples, the PEG corresponds to a shorter in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a larger PEG. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the receptor signaling efficacy of the modified IL-2 polypeptide to the IL-2βγ or IL-2αβγ signaling complex. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the desired reduced binding of the modified IL-2 polypeptide to IL-2Rα or maintained binding to the IL-2Rβγ signaling complex, where the reduced binding to IL-2Rα is compared to the binding between the wild-type IL-2 polypeptide and IL-2Rα. In some embodiments, the molecular weight of PEG does not affect the formation of the modified IL-2 polypeptide / IL-2Rβγ complex, and the reduced binding to IL-2Rα is compared to the binding between wild-type IL-2 polypeptide and IL-2Rα.

[0145] In some embodiments, the modified IL-2 polypeptide comprising a mutation at residue D19, corresponding to position 19 of SEQ ID NO:3, comprises a conjugation moiety comprising a PEG having a molecular weight of about 2,000 to 60,000 Da. In some embodiments, the molecular weight comprises 5,000 Da. In some embodiments, the molecular weight comprises 10,000 Da. In some embodiments, the molecular weight comprises 15,000 Da. In some embodiments, the molecular weight comprises 20,000 Da. In some embodiments, the molecular weight comprises 25,000 Da. In some embodiments, the molecular weight comprises 30,000 Da. In some embodiments, the molecular weight comprises 35,000 Da. In some embodiments, the molecular weight comprises 40,000 Da. In some embodiments, the molecular weight comprises 45,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 55,000 Da. In some embodiments, the molecular weight comprises 60,000 Da. In some embodiments, the molecular weight of the PEG at least partially determines the in vivo plasma half-life of the modified IL-2 polypeptide. In some examples, the PEG corresponds to a longer in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a smaller PEG. In some examples, the PEG corresponds to a shorter in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a larger PEG. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the receptor signaling efficacy of the modified IL-2 polypeptide to the IL-2βγ or IL-2αβγ signaling complex. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the desired reduced binding of the modified IL-2 polypeptide to IL-2Rα or maintained binding to the IL-2Rβγ signaling complex, where the reduced binding to IL-2Rα is compared to the binding between the wild-type IL-2 polypeptide and IL-2Rα. In some embodiments, the molecular weight of PEG does not affect the formation of the modified IL-2 polypeptide / IL-2Rβγ complex, and the reduced binding to IL-2Rα is compared to the binding between wild-type IL-2 polypeptide and IL-2Rα.

[0146] In some embodiments, the modified IL-2 polypeptide comprising a mutation at residue M22, corresponding to position 22 of SEQ ID NO: 3, comprises a conjugation moiety comprising a PEG having a molecular weight of about 2,000 to 60,000 Da. In some embodiments, the molecular weight comprises 5,000 Da. In some embodiments, the molecular weight comprises 10,000 Da. In some embodiments, the molecular weight comprises 15,000 Da. In some embodiments, the molecular weight comprises 20,000 Da. In some embodiments, the molecular weight comprises 25,000 Da. In some embodiments, the molecular weight comprises 30,000 Da. In some embodiments, the molecular weight comprises 35,000 Da. In some embodiments, the molecular weight comprises 40,000 Da. In some embodiments, the molecular weight comprises 45,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 55,000 Da. In some embodiments, the molecular weight comprises 60,000 Da. In some embodiments, the molecular weight of the PEG at least partially determines the in vivo plasma half-life of the modified IL-2 polypeptide. In some examples, the PEG corresponds to a longer in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a smaller PEG. In some examples, the PEG corresponds to a shorter in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a larger PEG. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the receptor signaling efficacy of the modified IL-2 polypeptide to the IL-2βγ or IL-2αβγ signaling complex. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the desired reduced binding of the modified IL-2 polypeptide to IL-2Rα or maintained binding to the IL-2Rβγ signaling complex, where the reduced binding to IL-2Rα is compared to the binding between the wild-type IL-2 polypeptide and IL-2Rα. In some embodiments, the molecular weight of PEG does not affect the formation of the modified IL-2 polypeptide / IL-2Rβγ complex, and the reduced binding to IL-2Rα is compared to the binding between wild-type IL-2 polypeptide and IL-2Rα.

[0147] In some embodiments, the modified IL-2 polypeptide comprising a mutation at residue N25, corresponding to position 25 of SEQ ID NO:3, comprises a conjugation moiety comprising a PEG having a molecular weight of about 2,000 to 60,000 Da. In some embodiments, the molecular weight comprises 5,000 Da. In some embodiments, the molecular weight comprises 10,000 Da. In some embodiments, the molecular weight comprises 15,000 Da. In some embodiments, the molecular weight comprises 20,000 Da. In some embodiments, the molecular weight comprises 25,000 Da. In some embodiments, the molecular weight comprises 30,000 Da. In some embodiments, the molecular weight comprises 35,000 Da. In some embodiments, the molecular weight comprises 40,000 Da. In some embodiments, the molecular weight comprises 45,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 55,000 Da. In some embodiments, the molecular weight comprises 60,000 Da. In some embodiments, the molecular weight of the PEG at least partially determines the in vivo plasma half-life of the modified IL-2 polypeptide. In some examples, the PEG corresponds to a longer in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a smaller PEG. In some examples, the PEG corresponds to a shorter in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a larger PEG. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the receptor signaling efficacy of the modified IL-2 polypeptide to the IL-2βγ or IL-2αβγ signaling complex. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the desired reduced binding of the modified IL-2 polypeptide to IL-2Rα or maintained binding to the IL-2Rβγ signaling complex, where the reduced binding to IL-2Rα is compared to the binding between the wild-type IL-2 polypeptide and IL-2Rα. In some embodiments, the molecular weight of PEG does not affect the formation of the modified IL-2 polypeptide / IL-2Rβγ complex, and the reduced binding to IL-2Rα is compared to the binding between wild-type IL-2 polypeptide and IL-2Rα.

[0148] In some embodiments, the modified IL-2 polypeptide comprising a mutation at residue N87, corresponding to position 87 of SEQ ID NO:3, comprises a conjugation moiety comprising a PEG having a molecular weight of about 2,000 to 60,000 Da. In some embodiments, the molecular weight comprises 5,000 Da. In some embodiments, the molecular weight comprises 10,000 Da. In some embodiments, the molecular weight comprises 15,000 Da. In some embodiments, the molecular weight comprises 20,000 Da. In some embodiments, the molecular weight comprises 25,000 Da. In some embodiments, the molecular weight comprises 30,000 Da. In some embodiments, the molecular weight comprises 35,000 Da. In some embodiments, the molecular weight comprises 40,000 Da. In some embodiments, the molecular weight comprises 45,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 55,000 Da. In some embodiments, the molecular weight comprises 60,000 Da. In some embodiments, the molecular weight of the PEG at least partially determines the in vivo plasma half-life of the modified IL-2 polypeptide. In some examples, the PEG corresponds to a longer in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a smaller PEG. In some examples, the PEG corresponds to a shorter in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a larger PEG. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the receptor signaling efficacy of the modified IL-2 polypeptide to the IL-2βγ or IL-2αβγ signaling complex. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the desired reduced binding of the modified IL-2 polypeptide to IL-2Rα or maintained binding to the IL-2Rβγ signaling complex, where the reduced binding to IL-2Rα is compared to the binding between the wild-type IL-2 polypeptide and IL-2Rα. In some embodiments, the molecular weight of PEG does not affect the formation of the modified IL-2 polypeptide / IL-2Rβγ complex, and the reduced binding to IL-2Rα is compared to the binding between wild-type IL-2 polypeptide and IL-2Rα.

[0149] In some embodiments, the modified IL-2 polypeptide comprising a mutation at residue E99, corresponding to position 99 of SEQ ID NO:3, comprises a conjugation moiety comprising a PEG having a molecular weight of about 2,000 to 60,000 Da. In some embodiments, the molecular weight comprises 5,000 Da. In some embodiments, the molecular weight comprises 10,000 Da. In some embodiments, the molecular weight comprises 15,000 Da. In some embodiments, the molecular weight comprises 20,000 Da. In some embodiments, the molecular weight comprises 25,000 Da. In some embodiments, the molecular weight comprises 30,000 Da. In some embodiments, the molecular weight comprises 35,000 Da. In some embodiments, the molecular weight comprises 40,000 Da. In some embodiments, the molecular weight comprises 45,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 55,000 Da. In some embodiments, the molecular weight comprises 60,000 Da. In some embodiments, the molecular weight of the PEG at least partially determines the in vivo plasma half-life of the modified IL-2 polypeptide. In some examples, the PEG corresponds to a longer in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a smaller PEG. In some examples, the PEG corresponds to a shorter in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a larger PEG. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the receptor signaling efficacy of the modified IL-2 polypeptide to the IL-2βγ or IL-2αβγ signaling complex. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the desired reduced binding of the modified IL-2 polypeptide to IL-2Rα or maintained binding to the IL-2Rβγ signaling complex, where the reduced binding to IL-2Rα is compared to the binding between the wild-type IL-2 polypeptide and IL-2Rα. In some embodiments, the molecular weight of PEG does not affect the formation of the modified IL-2 polypeptide / IL-2Rβγ complex, and the reduced binding to IL-2Rα is compared to the binding between wild-type IL-2 polypeptide and IL-2Rα.

[0150] In some embodiments, the modified IL-2 polypeptide comprising a mutation at residue N118, corresponding to position 118 of SEQ ID NO: 3, comprises a conjugation moiety comprising a PEG having a molecular weight of about 2,000 to 60,000 Da. In some embodiments, the molecular weight comprises 5,000 Da. In some embodiments, the molecular weight comprises 10,000 Da. In some embodiments, the molecular weight comprises 15,000 Da. In some embodiments, the molecular weight comprises 20,000 Da. In some embodiments, the molecular weight comprises 25,000 Da. In some embodiments, the molecular weight comprises 30,000 Da. In some embodiments, the molecular weight comprises 35,000 Da. In some embodiments, the molecular weight comprises 40,000 Da. In some embodiments, the molecular weight comprises 45,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 55,000 Da. In some embodiments, the molecular weight comprises 60,000 Da. In some embodiments, the molecular weight of the PEG at least partially determines the in vivo plasma half-life of the modified IL-2 polypeptide. In some examples, the PEG corresponds to a longer in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a smaller PEG. In some examples, the PEG corresponds to a shorter in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a larger PEG. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the receptor signaling efficacy of the modified IL-2 polypeptide to the IL-2βγ or IL-2αβγ signaling complex. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the desired reduced binding of the modified IL-2 polypeptide to IL-2Rα or maintained binding to the IL-2Rβγ signaling complex, where the reduced binding to IL-2Rα is compared to the binding between the wild-type IL-2 polypeptide and IL-2Rα. In some embodiments, the molecular weight of PEG does not affect the formation of the modified IL-2 polypeptide / IL-2Rβγ complex, and the reduced binding to IL-2Rα is compared to the binding between wild-type IL-2 polypeptide and IL-2Rα.

[0151] In some embodiments, the modified IL-2 polypeptide comprising a mutation at residue T122, corresponding to position 122 of SEQ ID NO: 3, comprises a conjugation moiety comprising a PEG having a molecular weight of about 2,000 to 60,000 Da. In some embodiments, the molecular weight comprises 5,000 Da. In some embodiments, the molecular weight comprises 10,000 Da. In some embodiments, the molecular weight comprises 15,000 Da. In some embodiments, the molecular weight comprises 20,000 Da. In some embodiments, the molecular weight comprises 25,000 Da. In some embodiments, the molecular weight comprises 30,000 Da. In some embodiments, the molecular weight comprises 35,000 Da. In some embodiments, the molecular weight comprises 40,000 Da. In some embodiments, the molecular weight comprises 45,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 55,000 Da. In some embodiments, the molecular weight comprises 60,000 Da. In some embodiments, the molecular weight of the PEG at least partially determines the in vivo plasma half-life of the modified IL-2 polypeptide. In some examples, the PEG corresponds to a longer in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a smaller PEG. In some examples, the PEG corresponds to a shorter in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a larger PEG. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the receptor signaling efficacy of the modified IL-2 polypeptide to the IL-2βγ or IL-2αβγ signaling complex. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the desired reduced binding of the modified IL-2 polypeptide to IL-2Rα or maintained binding to the IL-2Rβγ signaling complex, where the reduced binding to IL-2Rα is compared to the binding between the wild-type IL-2 polypeptide and IL-2Rα. In some embodiments, the molecular weight of PEG does not affect the formation of the modified IL-2 polypeptide / IL-2Rβγ complex, and the reduced binding to IL-2Rα is compared to the binding between wild-type IL-2 polypeptide and IL-2Rα.

[0152] In some embodiments, the modified IL-2 polypeptide comprising a mutation at residue Q125, corresponding to position 125 of SEQ ID NO:3, comprises a conjugation moiety comprising a PEG having a molecular weight of about 2,000 to 60,000 Da. In some embodiments, the molecular weight comprises 5,000 Da. In some embodiments, the molecular weight comprises 10,000 Da. In some embodiments, the molecular weight comprises 15,000 Da. In some embodiments, the molecular weight comprises 20,000 Da. In some embodiments, the molecular weight comprises 25,000 Da. In some embodiments, the molecular weight comprises 30,000 Da. In some embodiments, the molecular weight comprises 35,000 Da. In some embodiments, the molecular weight comprises 40,000 Da. In some embodiments, the molecular weight comprises 45,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 55,000 Da. In some embodiments, the molecular weight comprises 60,000 Da. In some embodiments, the molecular weight of the PEG at least partially determines the in vivo plasma half-life of the modified IL-2 polypeptide. In some examples, the PEG corresponds to a longer in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a smaller PEG. In some examples, the PEG corresponds to a shorter in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a larger PEG. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the receptor signaling efficacy of the modified IL-2 polypeptide to the IL-2βγ or IL-2αβγ signaling complex. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the desired reduced binding of the modified IL-2 polypeptide to IL-2Rα or maintained binding to the IL-2Rβγ signaling complex, where the reduced binding to IL-2Rα is compared to the binding between the wild-type IL-2 polypeptide and IL-2Rα. In some embodiments, the molecular weight of PEG does not affect the formation of the modified IL-2 polypeptide / IL-2Rβγ complex, and the reduced binding to IL-2Rα is compared to the binding between wild-type IL-2 polypeptide and IL-2Rα.

[0153] In some embodiments, the modified IL-2 polypeptide comprising a mutation at residue S126, corresponding to position 126 of SEQ ID NO: 3, comprises a conjugation moiety comprising a PEG having a molecular weight of about 2,000 to 60,000 Da. In some embodiments, the molecular weight comprises 5,000 Da. In some embodiments, the molecular weight comprises 10,000 Da. In some embodiments, the molecular weight comprises 15,000 Da. In some embodiments, the molecular weight comprises 20,000 Da. In some embodiments, the molecular weight comprises 25,000 Da. In some embodiments, the molecular weight comprises 30,000 Da. In some embodiments, the molecular weight comprises 35,000 Da. In some embodiments, the molecular weight comprises 40,000 Da. In some embodiments, the molecular weight comprises 45,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 55,000 Da. In some embodiments, the molecular weight comprises 60,000 Da. In some embodiments, the molecular weight of the PEG at least partially determines the in vivo plasma half-life of the modified IL-2 polypeptide. In some examples, the PEG corresponds to a longer in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a smaller PEG. In some examples, the PEG corresponds to a shorter in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a larger PEG. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the receptor signaling efficacy of the modified IL-2 polypeptide to the IL-2βγ or IL-2αβγ signaling complex. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the desired reduced binding of the modified IL-2 polypeptide to IL-2Rα or maintained binding to the IL-2Rβγ signaling complex, where the reduced binding to IL-2Rα is compared to the binding between the wild-type IL-2 polypeptide and IL-2Rα. In some embodiments, the molecular weight of PEG does not affect the formation of the modified IL-2 polypeptide / IL-2Rβγ complex, and the reduced binding to IL-2Rα is compared to the binding between wild-type IL-2 polypeptide and IL-2Rα.

[0154] In some embodiments, the modified IL-2 polypeptide comprising a mutation at residue T130, corresponding to position 130 of SEQ ID NO:3, comprises a conjugation moiety comprising a PEG having a molecular weight of about 2,000 to 60,000 Da. In some embodiments, the molecular weight comprises 5,000 Da. In some embodiments, the molecular weight comprises 10,000 Da. In some embodiments, the molecular weight comprises 15,000 Da. In some embodiments, the molecular weight comprises 20,000 Da. In some embodiments, the molecular weight comprises 25,000 Da. In some embodiments, the molecular weight comprises 30,000 Da. In some embodiments, the molecular weight comprises 35,000 Da. In some embodiments, the molecular weight comprises 40,000 Da. In some embodiments, the molecular weight comprises 45,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 55,000 Da. In some embodiments, the molecular weight comprises 60,000 Da. In some embodiments, the molecular weight of the PEG at least partially determines the in vivo plasma half-life of the modified IL-2 polypeptide. In some examples, the PEG corresponds to a longer in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a smaller PEG. In some examples, the PEG corresponds to a shorter in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a larger PEG. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the receptor signaling efficacy of the modified IL-2 polypeptide to the IL-2βγ or IL-2αβγ signaling complex. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the desired reduced binding of the modified IL-2 polypeptide to IL-2Rα or maintained binding to the IL-2Rβγ signaling complex, where the reduced binding to IL-2Rα is compared to the binding between the wild-type IL-2 polypeptide and IL-2Rα. In some embodiments, the molecular weight of PEG does not affect the formation of the modified IL-2 polypeptide / IL-2Rβγ complex, and the reduced binding to IL-2Rα is compared to the binding between wild-type IL-2 polypeptide and IL-2Rα.

[0155] In some embodiments, the modified IL-2 polypeptide comprising mutations at residues D108 and N87, corresponding to positions 108 and 87, respectively, of SEQ ID NO: 3, comprises a conjugation moiety comprising a PEG having a molecular weight of about 2,000 to 60,000 Da. In some embodiments, the molecular weight comprises 5,000 Da. In some embodiments, the molecular weight comprises 10,000 Da. In some embodiments, the molecular weight comprises 15,000 Da. In some embodiments, the molecular weight comprises 20,000 Da. In some embodiments, the molecular weight comprises 25,000 Da. In some embodiments, the molecular weight comprises 30,000 Da. In some embodiments, the molecular weight comprises 35,000 Da. In some embodiments, the molecular weight comprises 40,000 Da. In some embodiments, the molecular weight comprises 45,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 55,000 Da. In some embodiments, the molecular weight comprises 60,000 Da. In some embodiments, the molecular weight of the PEG at least partially determines the in vivo plasma half-life of the modified IL-2 polypeptide. In some examples, the PEG corresponds to a longer in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a smaller PEG. In some examples, the PEG corresponds to a shorter in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a larger PEG. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the receptor signaling efficacy of the modified IL-2 polypeptide to the IL-2βγ or IL-2αβγ signaling complex. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the desired reduced binding of the modified IL-2 polypeptide to IL-2Rα or maintained binding to the IL-2Rβγ signaling complex, where the reduced binding to IL-2Rα is compared to the binding between the wild-type IL-2 polypeptide and IL-2Rα. In some embodiments, the molecular weight of PEG does not affect the formation of the modified IL-2 polypeptide / IL-2Rβγ complex, and the reduced binding to IL-2Rα is compared to the binding between wild-type IL-2 polypeptide and IL-2Rα.

[0156] In some embodiments, the modified IL-2 polypeptide comprising a mutation at residue V91, corresponding to position 91 of SEQ ID NO:3, comprises a conjugation moiety comprising a PEG having a molecular weight of about 2,000 to 60,000 Da. In some embodiments, the molecular weight comprises 5,000 Da. In some embodiments, the molecular weight comprises 10,000 Da. In some embodiments, the molecular weight comprises 15,000 Da. In some embodiments, the molecular weight comprises 20,000 Da. In some embodiments, the molecular weight comprises 25,000 Da. In some embodiments, the molecular weight comprises 30,000 Da. In some embodiments, the molecular weight comprises 35,000 Da. In some embodiments, the molecular weight comprises 40,000 Da. In some embodiments, the molecular weight comprises 45,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 50,000 Da. In some embodiments, the molecular weight comprises 55,000 Da. In some embodiments, the molecular weight comprises 60,000 Da. In some embodiments, the molecular weight of the PEG at least partially determines the in vivo plasma half-life of the modified IL-2 polypeptide. In some examples, the PEG corresponds to a longer in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a smaller PEG. In some examples, the PEG corresponds to a shorter in vivo plasma half-life of the modified IL-2 polypeptide compared to the in vivo plasma half-life of a larger PEG. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the receptor signaling efficacy of the modified IL-2 polypeptide to the IL-2βγ or IL-2αβγ signaling complex. In some embodiments, the molecular weight of the PEG does not affect, or has minimal effect on, the desired reduced binding of the modified IL-2 polypeptide to IL-2Rα or maintained binding to the IL-2Rβγ signaling complex, where the reduced binding to IL-2Rα is compared to the binding between the wild-type IL-2 polypeptide and IL-2Rα. In some embodiments, the molecular weight of PEG does not affect the formation of the modified IL-2 polypeptide / IL-2Rβγ complex, and the reduced binding to IL-2Rα is compared to the binding between wild-type IL-2 polypeptide and IL-2Rα.

[0157] Cytokine conjugate precursor Described herein are cytokine conjugate precursors comprising mutant cytokines (e.g., IL-2) in which one or more amino acids have been mutated from the wild-type amino acid. Such precursors are often used in conjunction with the methods described herein for the treatment of diseases or conditions. In some embodiments, the cytokine precursor is not conjugated. Such mutations may include various additions, deletions, or substitutions. In some embodiments, the mutations include substitutions with a different naturally occurring amino acid. In some examples, the mutant cytokine is selected from the group consisting of amino acid positions P1, T2, S3, S4, S5, T6, K7, K8, Q10, L11, E14, H15, L17, L18, D19, Q21, M22, N25, G26, N28, N29, Y30, K31, K34, T36, M45, P46, K47, A49, T50, E51, L52, K53, H54, Q56, E59, E66, N70, Q73, S74, K75, N76, F77, H78, R80, P81, R82, D83, S86, N87, N88, N89, N90, N91, N92, N93, N94, N95, N96, N97, N98, N99, N100, N101, N102, N103, N104, N105, N106, N107, N108, N109, N110, N111, N112, N113, N114, N115, N116, N117, N118, N119, N120, N121, N122, N123, N124, N125, N126, N127, N128, N130, N131, N132, N133, N134, N135, N136, N137, N138, N140, N141, N142, N143, N144, N145, N146, N147, N148, N149, N150, N151, N152 The N87R variant contains mutations at positions 87, 188, V90, 191, L93, E94, K96, G97, S98, E99, T100, T101, F102, M103, C104, E105, Y106, A107, D108, D108 in the N87R variant, E109, T110, A111, T112, E115, N118, R119, T122, F123, S124, Q125, S126, S129, T130, L131, and T132, with amino acid residue numbering corresponding to SEQ ID NO:3. In some examples, the amino acid positions are selected from K8, H15, L18, D19, M22, N25, N87, V90, I91, L93, E94, K96, G97, S98, E99, D108 in the N87R variant, N118, T122, S124, Q125, S126, S129, and T130. In some examples, the amino acid positions are selected from K8, H15, L18, D19, M22, N25, N87, V90, E99, D108 in the N87R variant, N118, T122, S124, and T130. In some examples, the amino acid positions are selected from K8, H15, L18, D19, M22, N25, N87, V90, and E99.In some examples, the amino acid positions are selected from K8, H15, L18, D19, M22, N25, N87, V90, and E99. In some examples, the amino acid positions are selected from M22, N25, N87, V90, E99, D108 in the N87R variant, and N118. In some examples, the amino acid positions are selected from P1, T2, S3, S4, S5, T6, K7, K8, Q10, L11, E14, H15, L17, L18, D19, Q21, M22, N25, G26, N28, N29, and Y30. In some examples, the amino acid positions are selected from E14, H15, L17, and L18. In some examples, the amino acid positions are selected from S3, S4, S5, T6, K7, K8, Q10. In some examples, the amino acid position is selected from D19, M22, N25, and N87. Optionally, the amino acid position is at K8. Optionally, the amino acid position is at H15. Optionally, the amino acid position is at L18. Optionally, the amino acid position is at D19. Optionally, the amino acid position is at M22. Optionally, the amino acid position is at N25. Optionally, the amino acid position is at N87. Optionally, the amino acid position is at E99. Optionally, the amino acid position is at N118. Optionally, the amino acid position is at T122. Optionally, the amino acid position is at Q125. Optionally, the amino acid position is at S126. Optionally, the amino acid position is at T130. Optionally, the amino acid positions are at N87 and D108. Optionally, the amino acid position is at V90. Optionally, the amino acid position is at D108. In some embodiments, the cytokine mutant comprises a conjugation moiety, and the conjugation moiety is attached to the mutated site in the mutant cytokine.

[0158] The cytokine mutants described herein often contain one or more mutations to natural amino acids. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and at least one mutation. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and an H15K mutation. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and an H15C mutation. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and an H15A mutation. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and an H15I mutation. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and an H15L mutation. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and an H15Y mutation. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and an H15W mutation. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and an H15N mutation. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and an H15R mutation. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and an H15D mutation. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and an H15Q mutation. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and an H15G mutation. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and an H15H mutation. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and an H15M mutation. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and an H15F mutation. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and an H15P mutation. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and an H15S mutation. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and an H15T mutation. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and an H15V mutation.

[0159] The cytokine mutants described herein often contain one or more mutations to natural amino acids. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and at least one mutation. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and an N87K mutation. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and an N87C mutation. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and an N87A mutation. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and an N87I mutation. In some embodiments, the cytokine mutant comprises SEQ ID NO:3 and an N87L mutation. In some embodiments, the ...

Claims

1. 1. An IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (I): 【Chemistry 1】 (In the formula: Z is CH ２ and Y is 【Chemistry 2】 and Y is CH ２ and Z is 【Transformation 3】 and Z is CH ２ and Y is 【Chemistry 4】 or Y is CH ２ and Z is 【Transformation 5】 and W is a PEG group having an average molecular weight selected from 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, and 60 kDa; X has the structure: 【Transformation 6】 having X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue. has been replaced by; The positions of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate are: P1, T2, S3, S4, S5, T6, K7, K8, Q10, L11, E14, H15, L17, L18, D19, Q21, M22, N25, G26, N28, N29, Y30, K31, K34, T36, M45, P46, K47, A49, T50, E51, L52, K53, H54, Q56, E59, E66, N70, Q73, S74, K75, N76, F77, H78, R80, P81, R82, IL-2 conjugates selected from D83, S86, N87, 188, V90, 191, L93, E94, K96, G97, S98, E99, T100, T101, F102, M103, C104, E105, Y106, A107, D108, D108, E109, T110, A111, T112, E115, N118, R119, T122, F123, S124, Q125, S126, S129, T130, L131, and T132 in the N87R variant.

2. 1. An IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 4, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (I): 【Transformation 7】 (In the formula: Z is CH ２ and Y is 【Transformation 8】 and Y is CH ２ and Z is 【Chemistry 9】 and Z is CH ２ and Y is 【Chemistry 10】 or Y is CH ２ and Z is 【Chemistry 11】 and W is a PEG group having an average molecular weight selected from 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, and 60 kDa; X has the structure: 【Chemistry 12】 having X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue. has been replaced by; The positions of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate are A1, P2, T3, S4, S5, S6, T7, K8, K9, Q11, L12, E15, H16, L18, L19, D20, Q22, M23, N26, G27, N29, N30, Y31, K32, K35, T37, M46, P47, K48, A50, T51, E52, L53, H55, Q57, E60, E67, N71, Q74, S75, K76, N77, F78, H79, R81, P82, R8 3, D84, S87, N88, 189, V91, 192, L94, E95, K97, G98, S99, E100, T101, T102, F103, M104, C105, E106, Y107, A108, D109, D109, E110, T111, A112, T113, E116, N119, R120, T123, S125, Q126, S127, S130, T131, L132, and T133 in the N88R variant.

3. Z is CH ２ and Y is 【Chemistry 13】 3. The IL-2 conjugate according to claim 1 or 2, wherein

4. Y is CH ２ and Z is 【Chemistry 14】 3. The IL-2 conjugate according to claim 1 or 2, wherein

5. Z is CH ２ and Y is 【Chemistry 15】 3. The IL-2 conjugate according to claim 1 or 2, wherein

6. Z is CH ２ and Y is 【Chemistry 16】 and W is a PEG group having an average molecular weight selected from 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, and 60 kDa.

7. Y is CH ２ and Z is 【Chemistry 17】 3. The IL-2 conjugate according to claim 1 or 2, wherein

8. 8. The IL-2 conjugate of claim 1, wherein the PEG group has an average molecular weight selected from 5 kDa, 10 kDa, 20 kDa, 30 kDa, 40 kDa, or 50 kDa.

9. 9. The IL-2 conjugate of claim 8, wherein the PEG group has an average molecular weight of 50 kDa.

10. 9. The IL-2 conjugate of claim 8, wherein the PEG group has an average molecular weight of 30 kDa.

11. 11. The IL-2 conjugate according to any one of claims 1 to 10, wherein the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is K9.

12. 11. The IL-2 conjugate according to any one of claims 1 to 10, wherein the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is H16.

13. The position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is L19. The IL-2 conjugate according to any one of claims 1 to 10,

14. 11. The IL-2 conjugate according to any one of claims 1 to 10, wherein the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is D20.

15. 11. The IL-2 conjugate according to any one of claims 1 to 10, wherein the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is M23.

16. 11. The IL-2 conjugate according to any one of claims 1 to 10, wherein the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is N26.

17. 11. The IL-2 conjugate according to any one of claims 1 to 10, wherein the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is N88.

18. 11. The IL-2 conjugate according to any one of claims 1 to 10, wherein the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is V91.

19. 11. The IL-2 conjugate according to any one of claims 1 to 10, wherein the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is E100.

20. 11. The IL-2 conjugate according to any one of claims 1 to 10, wherein the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is D109 in the N88R variant.

21. 11. The IL-2 conjugate according to any one of claims 1 to 10, wherein the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is N119.

22. 11. The IL-2 conjugate according to any one of claims 1 to 10, wherein the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is T123.

23. 11. The IL-2 conjugate according to any one of claims 1 to 10, wherein the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is T131.

24. An IL-2 conjugate comprising any one of the amino acid sequences of SEQ ID NOs: 34-48, and 199-213, wherein [AzK_PEG] has the structure of formula (II) or formula (III), or a mixture of formulas (II) and (III): [Chemistry 18] (In the formula: W is a PEG group having an average molecular weight selected from 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, and 60 kDa; X has the structure: 【Chemistry 19】 having X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue. The IL-2 conjugate having the formula:

25. An IL-2 conjugate comprising any one of the amino acid sequences of SEQ ID NOs: 49-63 and 214-228, [AzK_PEG50kDa] having the structure of formula (II) or formula (III), or a mixture of formulas (II) and (III): 【Chemistry 20】 (In the formula: W is a PEG group having an average molecular weight of 50 kDa; X has the structure: 【Chemistry 21】 having X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue. The IL-2 conjugate having the formula:

26. An IL-2 conjugate comprising the amino acid sequence of any one of SEQ ID NOs: 64-78 and 229-245, wherein [AzK_PEG30kDa] has a structure of formula (II) or formula (III), or a mixture of the structures of formula (II) and formula (III): 【Chemistry 22】 (In the formula: W is a PEG group with an average molecular weight of 30 kDa; X has the structure: 【Chemistry 23】 having X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue. The IL-2 conjugate,

27. 27. The IL-2 conjugate of claim 26, having the amino acid sequence of SEQ ID NO:

64.

28. 27. The IL-2 conjugate of claim 26, having the amino acid sequence of SEQ ID NO:

65.

29. 27. The IL-2 conjugate of claim 26, having the amino acid sequence of SEQ ID NO:

66.

30. 27. The IL-2 conjugate of claim 26, having the amino acid sequence of SEQ ID NO:

67.

31. 27. The IL-2 conjugate of claim 26, having the amino acid sequence of SEQ ID NO:

68.

32. 27. The IL-2 conjugate of claim 26, having the amino acid sequence of SEQ ID NO:

69.

33. 27. The IL-2 conjugate of claim 26, having the amino acid sequence of SEQ ID NO:

71.

34. 27. The IL-2 conjugate of claim 26, having the amino acid sequence of SEQ ID NO:

72.

35. 27. The IL-2 conjugate of claim 26, having the amino acid sequence of SEQ ID NO:

73.

36. 27. The IL-2 conjugate of claim 26, having the amino acid sequence of SEQ ID NO:

74.

37. 27. The IL-2 conjugate of claim 26, having the amino acid sequence of SEQ ID NO:

75.

38. 27. The IL-2 conjugate of claim 26, having the amino acid sequence of SEQ ID NO:

76.

39. 27. The IL-2 conjugate of claim 26, having the amino acid sequence of SEQ ID NO:

244.

40. 27. The IL-2 conjugate of claim 26, having the amino acid sequence of SEQ ID NO:

245.

41. An IL-2 conjugate comprising the amino acid sequence of any one of SEQ ID NOs: 34-48 and 199-213, wherein [AzK_PEG] is a mixture of structures of formula (II) and formula (III): 【Chemistry 24】 (In the formula: W is a PEG group having an average molecular weight selected from 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, and 60 kDa; X has the structure: 【Chemistry 25】 having X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue. The IL-2 conjugate,

42. An IL-2 conjugate comprising any one of the amino acid sequences of SEQ ID NOs: 49-63 and 214-228, [AzK_PEG50kDa] being a mixture of structures of formula (II) and formula (III): 【Chemistry 26】 (In the formula: W is a PEG group having an average molecular weight of 50 kDa; X has the structure: 【Chemistry 27】 having X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue. The IL-2 conjugate,

43. An IL-2 conjugate comprising any one of the amino acid sequences of SEQ ID NOs: 64-78 and 229-245, wherein [AzK_PEG30kDa] is a mixture of structures of formula (II) and formula (III): 【Chemistry 28】 (In the formula: W is a PEG group with an average molecular weight of 30 kDa; X has the structure: 【Chemistry 29】 having X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue. The IL-2 conjugate,

44. An IL-2 conjugate comprising the amino acid sequence of any one of SEQ ID NOs: 154-168 and 109-123, wherein [AzK_L1_PEG] has the structure of formula (IV) or formula (V), or a mixture of formulas (IV) and (V): 【Transformation 30】 (In the formula: W is a PEG group having an average molecular weight selected from 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, and 60 kDa; X has the structure: 【Chemistry 31】 having X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue. The IL-2 conjugate having the formula:

45. An IL-2 conjugate comprising the amino acid sequence of any one of SEQ ID NOs: 169-183 and 124-138, [AzK_L1_PEG50kDa] having the structure of formula (IV) or formula (V), or a mixture of formulas (IV) and (V): 【Chemistry 32】 (In the formula: W is a PEG group having an average molecular weight of 50 kDa; X has the structure: 【Transformation 33】 having X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue. The IL-2 conjugate having the formula:

46. 46. ​​The IL-2 conjugate of claim 45, having the amino acid sequence of SEQ ID NO:

170.

47. An IL-2 conjugate comprising the amino acid sequence of any one of SEQ ID NOs: 184-198 and 139-153, wherein [AzK_L1_PEG30kDa] has a structure of formula (IV) or formula (V), or a mixture of the structures of formula (IV) and formula (V): 【Transformation 34】 (In the formula: W is a PEG group with an average molecular weight of 30 kDa; X has the structure: 【Chemistry 35】 having X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue. The IL-2 conjugate,

48. 48. The IL-2 conjugate of claim 47, having the amino acid sequence of SEQ ID NO:

185.

49. 48. The IL-2 conjugate of claim 47, having the amino acid sequence of SEQ ID NO:

190.

50. 48. The IL-2 conjugate of claim 47, having the amino acid sequence of SEQ ID NO:

197.

51. An IL-2 conjugate comprising the amino acid sequence of any one of SEQ ID NOs: 154-168 and 109-123, wherein [Azk_L1_PEG] is a mixture of structures of formula (IV) and formula (V): 【Transformation 36】 (In the formula: W is a PEG group having an average molecular weight selected from 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, 55 kDa, and 60 kDa; X has the structure: 【Chemistry 37】 having X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue. The IL-2 conjugate,

52. An IL-2 conjugate comprising the amino acid sequence of any one of SEQ ID NOs: 169-183 and 124-138, [AzK_L1_PEG50kDa] being a mixture of structures of formula (IV) and formula (V): 【Transformation 38】 (In the formula: W is a PEG group having an average molecular weight of 50 kDa; X has the structure: 【Chemistry 39】 having X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue. The IL-2 conjugate,

53. An IL-2 conjugate comprising the amino acid sequence of any one of SEQ ID NOs: 184-198 and 139-153, [AzK_L1_PEG30kDa] being a mixture of structures of formula (IV) and formula (V): 【Chemistry 40】 (In the formula: W is a PEG group with an average molecular weight of 30 kDa; X has the structure: 【Chemistry 41】 having X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue. The IL-2 conjugate,

54. 1. An IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (VI) or (VII), or a mixture of (VI) and (VII): 【Chemistry 42】 (In the formula: n is an integer ranging from about 2 to about 5000; X has the structure: 【Chemistry 43】 and X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue. wherein the IL-2 conjugate is replaced by

55. 1. An IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX): 【Chemistry 44】 (In the formula: n is an integer ranging from about 2 to about 5000; X has the structure: 【Chemistry 45】 and X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue. wherein the IL-2 conjugate is replaced by

56. 1. An IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (X) or (XI), or a mixture of (X) and (XI): 【Chemistry 46】 (In the formula: n is an integer ranging from about 2 to about 5000; The wavy line indicates a covalent bond to an amino acid residue in SEQ ID NO: 3 that is not replaced. wherein the IL-2 conjugate is replaced by

57. 1. An IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII): 【Chemistry 47】 (In the formula: n is an integer ranging from about 2 to about 5000; The wavy line indicates a covalent bond to an amino acid residue in SEQ ID NO: 3 that is not replaced. wherein the IL-2 conjugate is replaced by

58. 1. An IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 4, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (VI) or (VII), or a mixture of (VI) and (VII): 【Chemistry 48】 (In the formula: n is an integer ranging from about 2 to about 5000; X has the structure: 【Chemistry 49】 and X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue. wherein the IL-2 conjugate is replaced by

59. 1. An IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 4, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX): [Transformation 50] (In the formula: n is an integer ranging from about 2 to about 5000; X has the structure: 【Chemistry 51】 and X-1 indicates the point of attachment to the preceding amino acid residue; X+1 indicates the point of attachment to the subsequent amino acid residue. wherein the IL-2 conjugate is replaced by

60. 1. An IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 4, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (X) or (XI), or a mixture of (X) and (XI): 【Chemistry 52】 (In the formula: n is an integer ranging from about 2 to about 5000; The wavy line indicates a covalent bond to an amino acid residue in SEQ ID NO: 4 that is not replaced. wherein the IL-2 conjugate is replaced by

61. 1. An IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 4, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII): 【Chemistry 53】 (In the formula: n is an integer ranging from about 2 to about 5000; The wavy line indicates a covalent bond to an amino acid residue in SEQ ID NO: 4 that is not replaced. wherein the IL-2 conjugate is replaced by

62. 62. A method of treating an autoimmune disease in a subject, comprising administering to a subject in need thereof a therapeutically effective amount of an IL-2 conjugate of any one of claims 1 to 61.

63. Autoimmune diseases include graft-versus-host disease (GVHD), atopic dermatitis, Crohn's disease, alopecia areata, autoimmune hemolytic anemia, autoimmune hepatitis, dermatomyositis, type 1 diabetes, juvenile / childhood type 1 diabetes, juvenile idiopathic arthritis, glomerulonephritis, Graves' disease, Guillain-Barré syndrome, idiopathic thrombocytopenic purpura, myasthenia gravis, multiple sclerosis, pemphigus / pemphigoid, pernicious anemia, polyarteritis nodosa, polymyositis, primary biliary cholangitis, primary biliary cirrhosis, and non-small cell lung cancer.

63. The method of claim 62, wherein the disease is selected from the group consisting of alcoholic steatohepatitis (NASH), psoriasis, rheumatoid arthritis, scleroderma, CREST syndrome, Sjogren's syndrome, systemic lupus erythematosus, thyroiditis, uveitis, vitiligo, Wegener's granulomatosis, Addison's disease (adrenal insufficiency), Hashimoto's thyroiditis, autoimmune hepatitis, infertility, ANCA-associated vasculitis, psoriatic arthritis, celiac disease, ulcerative colitis, lichen sclerosus, and Behcet's disease.

64. 64. The method of any one of claims 62-63, wherein a subject in need thereof is determined to exhibit an increased concentration of rheumatoid factor in the subject's blood prior to administration of a therapeutically effective amount of the IL-2 conjugate to the subject.

65. 1. A method of treating rheumatoid arthritis in a subject in need thereof, comprising: (a) determining the concentration of rheumatoid factor in the blood of a subject; and (b) administering to a subject in need thereof a therapeutically effective amount of an IL-2 conjugate of any one of claims 1 to 61 when the concentration of rheumatoid factor in the subject's blood is greater than about 14 IU / mL. The method comprising:

66. 64. The method of any one of claims 62-63, wherein the subject in need thereof is determined to exhibit an abnormal erythrocyte sedimentation rate (ESR) test, optionally using the Westergren or Wintrobe rate methods, prior to administration of a therapeutically effective amount of the IL-2 conjugate to the subject.

67. 1. A method of treating an autoimmune disease in a subject in need thereof, comprising: (a) determining the erythrocyte sedimentation rate (ESR) in a subject; and (b) if the ESR is determined to be abnormal, administering to a subject in need thereof a therapeutically effective amount of an IL-2 conjugate according to any one of claims 1 to 61. The method comprising:

68. 1. A method of treating an autoimmune disease in a subject in need thereof, comprising: (a) determining the concentration of C-reactive protein (CRP) in the subject's blood; and (b) administering to a subject in need thereof a therapeutically effective amount of an IL-2 conjugate of any one of claims 1 to 61 if the concentration of C-reactive protein (CRP) in the subject's blood is determined to be abnormal. The method comprising:

69. 69. The method of claim 68, wherein the subject in need thereof is determined to exhibit a concentration of C-reactive protein (CRP) in the blood greater than 10 mg / L prior to administration of a therapeutically effective amount of the IL-2 conjugate to the subject.

70. 62. A method of treating rheumatoid arthritis in a subject in need thereof, comprising administering to a subject in need thereof a therapeutically effective amount of an IL-2 conjugate of any one of claims 1 to 61 when the concentration of anti-cyclic citrullinated peptide (anti-CCP) in the subject's blood is determined to be abnormal.

71. 62. A method of treating rheumatoid arthritis in a subject in need thereof, comprising administering to a subject in need thereof a therapeutically effective amount of an IL-2 conjugate of any one of claims 1-61 when the concentration of anti-cyclic citrullinated peptide (anti-CCP) in the subject's blood is determined to be greater than about 20 Iu / mL.

72. 1. A method for producing an IL-2 conjugate, comprising: formula 【Chemistry 54】 IL-2 polypeptide comprising an unnatural amino acid of formula X-1, wherein the IL-2 polypeptide comprises the amino acid sequence of SEQ ID NO: 3 or 4, and wherein at least one amino acid residue in the IL-2 polypeptide is replaced with an unnatural amino acid, wherein position X-1 indicates the point of attachment to the preceding amino acid residue, position X+1 indicates the point of attachment to the subsequent amino acid residue, and position X indicates the position of the amino acid substituted with the unnatural amino acid. 【Transformation 55】 wherein n is such that the mPEG-DBCO comprises a PEG having a molecular weight of about 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, or 50 kDa, thereby producing an IL-2 conjugate; Position X in the amino acid sequence of the IL-2 conjugate is selected from the group consisting of P1, T2, S3, S4, S5, T6, K7, K8, Q10, L11, E14, H15, L17, L18, D19, Q21, M22, N25, G26, N28, N29, Y30, K31, K34, T36, M45, P46, K47, A49, T50, E51, L52, K53, H54, Q56, E59, E66, N70, Q73, S74, K75, N76, F77, H78, R80, P81, R82, R83, R84, R85, R86, R87, R88, R89, R90, R91, R92, R93, R94, R95, R96, R97, R98, R99, R99, R100, R101, R102, R103, R104, R105, R106, R107, R108, R109, R110, R111, R112, R113, R114, R115, R116, R117, R118, R119, R120, R121, R122, R123, R124, R125, R126, R127, R128, R129, R130, R131, R132, R133, R134, R135, R136, R137, R138, R140, R141, R142, R143, R144, R145, R146, R147, R 82, D83, S86, N87, I88, V90, I91, L93, E94, K96, G97, S98, E99, T100, T101, F102, M103, C104, E105, Y106, A107, D108, D108, E109, T110, A111, T112, E115, N118, R119, T122, F123, S124, Q125, S126, S129, T130, L131, and T132 in the N87R variant, or IL-2 Position X in the amino acid sequence of the conjugate is, relative to the amino acid positions in SEQ ID NO: 4, A1, P2, T3, S4, S5, S6, T7, K8, K9, Q11, L12, E15, H16, L18, L19, D20, Q22, M23, N26, G27, N29, N30, Y31, K32, K35, T37, M46, P47, K48, A50, T51, E52, L53, H55, Q57, E60, E67, N71, Q74, S75, K76, N77, F78, H79, selected from R81, P82, R83, D84, S87, N88, I89, V91, I92, L94, E95, K97, G98, S99, E100, T101, T102, F103, M104, C105, E106, Y107, A108, D109, D109 in the N88R variant, E110, T111, A112, T113, E116, N119, R120, T123, S125, Q126, S127, S130, T131, L132, or T133; The method.

73. Position X is P1, T2, S3, S4, S5, T6, K7, K8, Q10, L11, E14, H15, L17, L18, D19, Q21, M22, N25, G26, N28, N29, Y30, K31, K34, T36, M45, P46, K47, A49, T50, E51, L52, K53, H54, Q56, E59, E66, N70, Q73, S74, K75, N76, F77, H78, R80, P81, R82, D8 3, S86, N87, I88, V90, I91, L93, E94, K96, G97, S98, E99, T100, T101, F102, M103, C104, E105, Y106, A107, D108, D108 in the N87R variant, E109, T110, A111, T112, E115, N118, R119, T122, F123, S124, Q125, S126, S129, T130, L131, or T132.

74. Position X is, based on the amino acid position in SEQ ID NO: 4, A1, P2, T3, S4, S5, S6, T7, K8, K9, Q11, L12, E15, H16, L18, L19, D20, Q22, M23, N26, G27, N29, N30, Y31, K32, K35, T37, M46, P47, K48, A50, T51, E52, L53, H55, Q57, E60, E67, N71, Q74, S75, K76, N77, F78, H79, R81, P82, R83, 73. The method of claim 72, wherein the amino acid residues at position 74 are D84, S87, N88, I89, V91, I92, L94, E95, K97, G98, S99, E100, T101, T102, F103, M104, C105, E106, Y107, A108, D109, D109, E110, T111, A112, T113, E116, N119, R120, T123, S125, Q126, S127, S130, T131, L132, or T133 in the N88R variant.

75. 75. The method of any one of claims 72 to 74, wherein the PEG has a molecular weight of about 30 kDa.

76. 75. The method of any one of claims 72 to 74, wherein the PEG has a molecular weight of about 50 kDa.

77. The method of claim 74, wherein the IL-2 conjugate is an IL-2 conjugate according to any one of claims 1 to 61.

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