Il-2 muteins and their use

Abstract

Novel recombinant interleukin-2 (IL-2) proteins are provided. In particular, provided are recombinant IL-2 proteins that are selectively mutated to be partial agonists of IL-2R-based signaling, or to increase IL-2R-based signaling, as compared to wild-type IL-2. The recombinant IL-2 proteins are useful, for example, in applications where fine-tuning one or more IL-2 functions is useful (e.g., in the treatment of autoimmune disease and cancer). Also provided are nucleic acids encoding the recombinant IL-2 proteins, methods of making the recombinant IL-2 proteins, pharmaceutical compositions that include the recombinant IL-2 proteins and methods of treatment using such pharmaceutical compositions.

Description

[0001]4239-112594-02 IL-2 MUTEINS AND THEIR USE CROSS REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No.63 / 707,970, filed October 16, 2024, which is herein incorporate by reference in its entirety. FIELD This disclosure concerns recombinant IL-2 proteins having specific amino acid substitutions that alter the binding properties and / or functional activity of IL-2. Use of the recombinant IL-2 proteins for treating autoimmune disease and cancer is also described. INCORPORATION OF ELECTRONIC SEQUENCE LISTING The electronic sequence listing, submitted herewith as an XML file named 4239- 112594-02.xml (48,068 bytes), created on September 29, 2025, is herein incorporated by reference in its entirety. BACKGROUND Interleukin-2 (IL-2) is a pleiotropic cytokine that is primarily produced by activated CD4+T cells. Among its broad actions, it enhances the cytotoxicity of natural killer (NK) cells and effector CD8+T cells, maintains T regulatory (Treg) function, and contributes to T helper cell differentiation. IL-2 can signal either via intermediate-affinity (Kd~ 1 nM) or high-affinity (Kd ~ 10 pM) IL-2 receptors (IL-2Rs). Intermediate-affinity receptors include IL-2Rβ and IL-2Rγ (also known as the common cytokine receptor chain, γc), whereas high- affinity receptors include IL-2Rα (also known as CD25), IL-2Rβ, and γc. Before activation, NK cells and effector T cells express intermediate affinity IL-2 receptors, whereas Treg cells (which suppress and limit immune responses) constitutively express high-affinity IL-2 receptors. Because IL-2 influences distinct immune cell populations, the need exists for methods of fine-tuning IL-2 signaling. SUMMARY IL-2 muteins (that is, recombinant IL-2 proteins containing one or more amino acid substitutions compared to wild-type IL-2) are provided herein. In particular, provided are recombinant IL-2 proteins that are selectively mutated to be partial agonists of IL-2R-based 4239-112594-02 signaling, or to increase IL-2R-based signaling, as compared to wild-type IL-2. The recombinant IL-2 proteins are useful, for example, in applications where fine-tuning one or more IL-2 functions is desired (e.g., in the treatment of autoimmune disease or cancer). In some aspects, the recombinant IL-2 protein includes Q22E and Q126T amino acid substitutions. In some aspects, the recombinant IL-2 protein includes L18R, Q22E, and S130R amino acid substitutions. In some aspects, the recombinant IL-2 protein includes L18R and Q126T amino acid substitutions. In some aspects, the recombinant IL-2 protein includes Q126T and S130R amino acid substitutions. In some examples, the recombinant IL- 2 protein optionally further includes L80F, R81D, L85V, I86V, and I92F amino acid substitutions. The amino acid numbering is according to the reference IL-2 protein sequence set forth as SEQ ID NO: 6. In some aspects, the recombinant IL-2 protein includes the Q22E and Q126T amino acid substitutions, the L18R and Q126T amino acid substitutions, or the Q126T and S130R amino acid substitutions, and has a reduced capability to stimulate STAT5 phosphorylation in T cells as compared to wild-type human IL-2. In some aspects, the recombinant IL-2 protein includes the Q22E and Q126T amino acid substitutions, the L18R and Q126T amino acid substitutions, or the Q126T and S130R amino acid substitutions, and induces proliferation of fewer CD8+T cells and more Treg cells as compared to wild-type human IL-2 when incubated with peripheral blood mononuclear cells (PBMCs). In some aspects, the recombinant IL-2 protein includes the Q22E and Q126T amino acid substitutions, the L18R and Q126T amino acid substitutions, or the Q126T and S130R amino acid substitutions, and induces a lower level of proliferation of CD8+T cells and a greater level of proliferation of Treg cells as compared to wild-type human IL-2 when incubated with PBMCs. In some aspects, the recombinant IL-2 protein includes the L18R, Q22E, and S130R amino acid substitutions, and has an increased capability to stimulate STAT5 phosphorylation in T cells as compared to wild-type human IL-2. In some aspects, the recombinant IL-2 protein is linked or fused to a heterologous protein, such as human serum albumin, mouse serum albumin, or a human Fc antibody fragment. In some aspects, a multimer of the recombinant IL-2 protein is provided. Nucleic acid molecules encoding the disclosed recombinant IL-2 protein are also provided. Expression vectors (such as an inactivated or attenuated viral vector) including the nucleic acid molecules are also provided. 4239-112594-02 Pharmaceutical compositions including the recombinant IL-2 protein are also provided. The composition may be contained in a unit dosage form. Methods of treatment are provided, including methods of administering to a subject in need thereof a therapeutically effective amount of a disclosed recombinant IL-2 protein, or a nucleic acid molecule or vector encoding the recombinant IL-2 protein, to treat an autoimmune disease in the subject. In additional aspects, a method of treating cancer in a subject is provided, including culturing T cells or NK cells with an effective amount of a disclosed recombinant IL-2 protein, or a nucleic acid molecule or vector encoding the recombinant IL-2 protein, thereby expanding the T cells; and adoptively transferring the expanded T cells to the subject to treat the cancer. In further aspects, methods are provided for expanding T cells by incubating the T cells with an amount of a disclosed recombinant IL-2 protein, or a nucleic acid molecule or vector encoding the recombinant IL-2 protein, effective to induce proliferation of the T cells. In some aspects, the method further includes administering the T cells to a patient in need thereof as an adoptive cell transfer therapy. In some examples, the subject has cancer. Any cell that is competent for IL-2 signaling can be treated with the recombinant IL-2 protein as described herein. In some aspects, the cells are T cells (such as CD8+T cells, CD4+T cells, or Tregs), NK cells, type 2 innate lymphoid cells (ILC2s), activated monocytes, or B cells. The foregoing and other features and advantages of this disclosure will become more apparent from the following detailed description of several aspects which proceeds with reference to the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES FIGS.1A-1D. pSTAT5 levels altered for IL-2 muteins. (FIG.1A) Experimental design for FIG.1B and FIG.1C. (FIG.1B) Mean fluorescence intensity (MFI) of pSTAT5 levels following treatment with WT IL-2 or selected IL-2 muteins in CD25+YT cells. (FIG. 1C) MFI of pSTAT5 levels following treatment with WT IL-2 and selected IL-2 muteins in CD25- YT cells. (FIG.1D) MFI of pSTAT5 levels following treatment with selected IL-2 muteins in preactivated human CD8+T cells. FIGS.2A-2C. IL-2-ET preferentially acts on CD25-expressing cells. Ki67 expression in CD8+T cells (FIG.2A), NK cells (FIG.2B), and Tregs (FIG.2C) isolated from 4239-112594-02 PBMCs from healthy donors. Cells were treated with varying concentrations of IL-2 muteins for 7 days. FIGS.3A-3C. IL-2-ET selectively expands Tregs in vivo. (FIG.3A) Schematic representation of in vivo cytokine injections. (FIG.3B) Percent of CD4+and CD8+T cells from spleens on day 7. (FIG.3C) Percent of Tregs from CD4+T cells in spleens on day 7. FIGS.4A-4F. IL-2-ET treated mice had less weight loss and symptoms of dextran sodium sulfate (DSS)-induced colitis. (FIG.4A) Schematic representation of the DSS- induced colitis model. Percent weight on day 9 (FIG.4B) and day 16 (FIG.4C) during the experiment. (FIG.4D) Histology scores as determined by analysis of H&E staining of colon sections. (FIG.4E) Percent CD8+T cells and (FIG.4F) % Tregs from mesenteric lymph nodes on day 16. FIGS.5A-5D. IL-2-ET preferentially acts on CD25-expressing cells in PBMCs from either normal donors or systemic lupus erythematosus (SLE) patients. (FIG.5A) Percent T cells and T-cell counts in PBMCs from normal donors and SLE patients, treated with IL-2 versus IL-2-ET. Ki67 expression on NK cells (FIG.5B), CD8+T cells (FIG.5C), and Tregs (FIG.5D). FIGS.6A-6C. CD8+T cells cultured with IL-2-ET have stem-like features, in contrast to cells cultured with IL-2. (FIG.6A) CD69, CD25, TCF1, and Ki67 expression on Pmel-1 CD8+T cells cultured for 10 days medium containing IL-2 or IL-2-ET. (FIG.6B) CD39 vs CD69 expression on the Pmel-1 CD8+T cells cultured in medium containing IL-2 or IL-2-ET. (FIG.6C) Lag3, Tim3, and 2B4 expression on Pmel-1 CD8+T cells cultured in a medium containing IL-2 or IL-2-ET. FIGS.7A-7C. Anti-tumor activity of IL-2-ET-treated cells. (FIG.7A) Pmel-1 CD8+T cells were cultured with PBS, IL-2, or IL-2-ET and then adoptively transferred into B16 melanoma-bearing mice. (FIG.7B) Percent survival of melanoma-bearing mice. (FIG.7C) Percent tumor-free of melanoma-bearing mice. FIGS.8A-8E. In vivo administration of IL-2-ET rescues NOD mice from developing type-1 diabetes. (FIG.8A) Schematic representation of the protocol for in vivo injection of IL-2, IL-2-ET, or PBS into NOD mice. (FIG.8B) Incidence of diabetes in female NOD mice treated with PBS, IL-2, or IL-2-ET. Representative of two independent experiments with n=10 mice / group. (FIG.8C) Frequency of CD8+T cells in spleen, pancreatic lymph node (pLN), and pancreas in female NOD mice treated with PBS, IL-2, or IL-2 ET at week 14. (FIG.8D) Frequency of Treg cells in spleen, pLN, and pancreas in female NOD mice treated with PBS, IL-2, or IL-2 ET at week 14. (FIG.8E) Top panel: Representative H&E staining 4239-112594-02 of the pancreas and the islet (dotted circles). Bottom panel: Severity (histology) score is based on a scale of 0-3; 5 mice each were treated with PBS (3), IL-2 (1), or IL-2 ET (2). Tissue was examined at week 14. SEQUENCES The amino acid sequences listed in the accompanying sequence listing are shown using single letter code for amino acids, as defined in 37 C.F.R.1.822. In the accompanying sequence listing: SEQ ID NO: 1 is the amino acid sequence of an exemplary IL-2 / MSA fusion protein, including signal peptide, mouse serum albumin (MSA), IL-2, and His tag. MVSAIVLYVLLAAAAHSAFARGVFRREAHKSEIAHRYNDLGEQHFKGLVLIAFSQYLQKCSYDEHAKLVQEVTDF AKTCVADESAANCDKSLHTLFGDKLCAIPNLRENYGELADCCTKQEPERNECFLQHKDDNPSLPPFERPEAEAMC TSFKENPTTFMGHYLHEVARRHPYFYAPELLYYAEQYNEILTQCCAEADKESCLTPKLDGVKEKALVSSVRQRMK CSSMQKFGERAFKAWAVARLSQTFPNADFAEITKLATDLTKVNKECCHGDLLECADDRAELAKYMCENQATISSKLQTCCDKPLLKKAHCLSEVEHDTMPADLPAIAADFVEDQEVCKNYAEAKDVFLGTFLYEYSRRHPDYSVSLLLRLAKKYEATLEKCCAEANPPACYGTVLAEFQPLVEEPKNLVKTNCDLYEKLGEYGFQNAILVRYTQKAPQVSTPTLV EAARNLGRVGTKCCTLPEDQRLPCVEDYLSAILNRVCLLHEKTPVSEHVTKCCSGSLVERRPCFSALTVDETYVP KEFKAETFTFHSDICTLPEKEKQIKKQTALAELVKHKPKATAEQLKTVMDDFAQFLDTCCKAADKDTCFSTEGPN LVTRCKDALAAPTSSSTKKTQLQLEHLLLDLQMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKPLEEVLNLAQSKNFHLRPRDLISNINVIVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIISTLTHHHHHHHH SEQ ID NO: 2 is the amino acid sequence of an exemplary signal peptide derived from MSA.MVSAIVLYVLLAAAAHSAFASEQ ID NO: 3 is the amino acid sequence of an exemplary signal peptide derived from human serum albumin (HSA). MKWVTFISLLFLFSSAYS SEQ ID NO: 4 is the amino acid sequence of an exemplary serum albumin, MSA, including signal peptide. MVSAIVLYVLLAAAAHSAFARGVFRREAHKSEIAHRYNDLGEQHFKGLVLIAFSQYLQKCSYDEHAKLVQEVTDF AKTCVADESAANCDKSLHTLFGDKLCAIPNLRENYGELADCCTKQEPERNECFLQHKDDNPSLPPFERPEAEAMCTSFKENPTTFMGHYLHEVARRHPYFYAPELLYYAEQYNEILTQCCAEADKESCLTPKLDGVKEKALVSSVRQRMKCSSMQKFGERAFKAWAVARLSQTFPNADFAEITKLATDLTKVNKECCHGDLLECADDRAELAKYMCENQATISSK LQTCCDKPLLKKAHCLSEVEHDTMPADLPAIAADFVEDQEVCKNYAEAKDVFLGTFLYEYSRRHPDYSVSLLLRL AKKYEATLEKCCAEANPPACYGTVLAEFQPLVEEPKNLVKTNCDLYEKLGEYGFQNAILVRYTQKAPQVSTPTLV EAARNLGRVGTKCCTLPEDQRLPCVEDYLSAILNRVCLLHEKTPVSEHVTKCCSGSLVERRPCFSALTVDETYVPKEFKAETFTFHSDICTLPEKEKQIKKQTALAELVKHKPKATAEQLKTVMDDFAQFLDTCCKAADKDTCFSTEGPNLVTRCKDALA 4239-112594-02 SEQ ID NO: 5 is the amino acid sequence of an exemplary serum albumin, HSA, including signal peptide. MKWVTFISLLFLFSSAYSRGVFRRDAHKSEVAHRFKDLGEENFKALVLIAFAQYLQQCPFEDHVKLVNEVTEFAK TCVADESAENCDKSLHTLFGDKLCTVATLRETYGEMADCCAKQEPERNECFLQHKDDNPNLPRLVRPEVDVMCTAFHDNEETFLKKYLYEIARRHPYFYAPELLFFAKRYKAAFTECCQAADKAACLLPKLDELRDEGKASSAKQRLKCASLQKFGERAFKAWAVARLSQRFPKAEFAEVSKLVTDLTKVHTECCHGDLLECADDRADLAKYICENQDSISSKLK ECCEKPLLEKSHCIAEVENDEMPADLPSLAADFVESKDVCKNYAEAKDVFLGMFLYEYARRHPDYSVVLLLRLAK TYETTLEKCCAAADPHECYAKVFDEFKPLVEEPQNLIKQNCELFEQLGEYKFQNALLVRYTKKVPQVSTPTLVEV SRNLGKVGSKCCKHPEAKRMPCAEDYLSVVLNQLCVLHEKTPVSDRVTKCCTESLVNRRPCFSALEVDETYVPKE FNAETFTFHADICTLSEKERQIKKQTALVELVKHKPKATKEQLKAVMDDFAAFVEKCCKADDKETCFAEEGKKLV AASQAALGL SEQ ID NO: 6 is the amino acid sequence of an exemplary human IL-2. APTSSSTKKTQLQLEHLLLDLQMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKPLEEVLNLAQSKNFHLRPRDLISNINVIVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIISTLTSEQ ID NO: 7 is the amino acid sequence of an exemplary His-tag. HHHHHHHH SEQ ID NO: 8 is the amino acid sequence of an exemplary IL-2-ET (containing two mutations as compared to native IL-2, Q22E and Q126T). APTSSSTKKTQLQLEHLLLDLEMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKPLEEVLNLAQS KNFHLRPRDLISNINVIVLELKGSETTFMCEYADETATIVEFLNRWITFCTSIISTLT SEQ ID NO: 9 is the amino acid sequence of an exemplary IL-2-ET MSA. MVSAIVLYVLLAAAAHSAFARGVFRREAHKSEIAHRYNDLGEQHFKGLVLIAFSQYLQKCSYDEHAKLVQEVTDF AKTCVADESAANCDKSLHTLFGDKLCAIPNLRENYGELADCCTKQEPERNECFLQHKDDNPSLPPFERPEAEAMC TSFKENPTTFMGHYLHEVARRHPYFYAPELLYYAEQYNEILTQCCAEADKESCLTPKLDGVKEKALVSSVRQRMK CSSMQKFGERAFKAWAVARLSQTFPNADFAEITKLATDLTKVNKECCHGDLLECADDRAELAKYMCENQATISSK LQTCCDKPLLKKAHCLSEVEHDTMPADLPAIAADFVEDQEVCKNYAEAKDVFLGTFLYEYSRRHPDYSVSLLLRL AKKYEATLEKCCAEANPPACYGTVLAEFQPLVEEPKNLVKTNCDLYEKLGEYGFQNAILVRYTQKAPQVSTPTLV EAARNLGRVGTKCCTLPEDQRLPCVEDYLSAILNRVCLLHEKTPVSEHVTKCCSGSLVERRPCFSALTVDETYVP KEFKAETFTFHSDICTLPEKEKQIKKQTALAELVKHKPKATAEQLKTVMDDFAQFLDTCCKAADKDTCFSTEGPN LVTRCKDALAAPTSSSTKKTQLQLEHLLLDLEMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKPLEEVLNLAQSKNFHLRPRDLISNINVIVLELKGSETTFMCEYADETATIVEFLNRWITFCTSIISTLTHHHHHHHH SEQ ID NO: 10 is the amino acid sequence of an exemplary IL-2-RT (containing two mutations as compared to native IL-2, L18R and Q126T). APTSSSTKKTQLQLEHLRLDLQMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKPLEEVLNLAQS KNFHLRPRDLISNINVIVLELKGSETTFMCEYADETATIVEFLNRWITFCTSIISTLT SEQ ID NO: 11 is the amino acid sequence of an exemplary IL-2-RT MSA. MVSAIVLYVLLAAAAHSAFARGVFRREAHKSEIAHRYNDLGEQHFKGLVLIAFSQYLQKCSYDEHAKLVQEVTDF AKTCVADESAANCDKSLHTLFGDKLCAIPNLRENYGELADCCTKQEPERNECFLQHKDDNPSLPPFERPEAEAMC TSFKENPTTFMGHYLHEVARRHPYFYAPELLYYAEQYNEILTQCCAEADKESCLTPKLDGVKEKALVSSVRQRMK CSSMQKFGERAFKAWAVARLSQTFPNADFAEITKLATDLTKVNKECCHGDLLECADDRAELAKYMCENQATISSK 4239-112594-02 LQTCCDKPLLKKAHCLSEVEHDTMPADLPAIAADFVEDQEVCKNYAEAKDVFLGTFLYEYSRRHPDYSVSLLLRL AKKYEATLEKCCAEANPPACYGTVLAEFQPLVEEPKNLVKTNCDLYEKLGEYGFQNAILVRYTQKAPQVSTPTLV EAARNLGRVGTKCCTLPEDQRLPCVEDYLSAILNRVCLLHEKTPVSEHVTKCCSGSLVERRPCFSALTVDETYVP KEFKAETFTFHSDICTLPEKEKQIKKQTALAELVKHKPKATAEQLKTVMDDFAQFLDTCCKAADKDTCFSTEGPN LVTRCKDALAAPTSSSTKKTQLQLEHLRLDLQMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKP LEEVLNLAQSKNFHLRPRDLISNINVIVLELKGSETTFMCEYADETATIVEFLNRWITFCTSIISTLTHHHHHHH H SEQ ID NO: 12 is the amino acid sequence of an exemplary IL-2-TR (containing two mutations as compared to native IL-2, Q126T and S130R). APTSSSTKKTQLQLEHLLLDLQMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKPLEEVLNLAQS KNFHLRPRDLISNINVIVLELKGSETTFMCEYADETATIVEFLNRWITFCTSIIRTLT SEQ ID NO: 13 is the amino acid sequence of an exemplary IL-2-TR MSA. MVSAIVLYVLLAAAAHSAFARGVFRREAHKSEIAHRYNDLGEQHFKGLVLIAFSQYLQKCSYDEHAKLVQEVTDF AKTCVADESAANCDKSLHTLFGDKLCAIPNLRENYGELADCCTKQEPERNECFLQHKDDNPSLPPFERPEAEAMC TSFKENPTTFMGHYLHEVARRHPYFYAPELLYYAEQYNEILTQCCAEADKESCLTPKLDGVKEKALVSSVRQRMK CSSMQKFGERAFKAWAVARLSQTFPNADFAEITKLATDLTKVNKECCHGDLLECADDRAELAKYMCENQATISSK LQTCCDKPLLKKAHCLSEVEHDTMPADLPAIAADFVEDQEVCKNYAEAKDVFLGTFLYEYSRRHPDYSVSLLLRL AKKYEATLEKCCAEANPPACYGTVLAEFQPLVEEPKNLVKTNCDLYEKLGEYGFQNAILVRYTQKAPQVSTPTLV EAARNLGRVGTKCCTLPEDQRLPCVEDYLSAILNRVCLLHEKTPVSEHVTKCCSGSLVERRPCFSALTVDETYVP KEFKAETFTFHSDICTLPEKEKQIKKQTALAELVKHKPKATAEQLKTVMDDFAQFLDTCCKAADKDTCFSTEGPN LVTRCKDALAAPTSSSTKKTQLQLEHLLLDLQMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKP LEEVLNLAQSKNFHLRPRDLISNINVIVLELKGSETTFMCEYADETATIVEFLNRWITFCTSIIRTLTHHHHHHH H SEQ ID NO: 14 is the amino acid sequence of an exemplary IL-2-ER (containing two mutations as compared to native IL-2, Q22E and S130R). APTSSSTKKTQLQLEHLLLDLEMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKPLEEVLNLAQSKNFHLRPRDLISNINVIVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIIRTLTSEQ ID NO: 15 is the amino acid sequence of an exemplary IL-2-ER MSA. MVSAIVLYVLLAAAAHSAFARGVFRREAHKSEIAHRYNDLGEQHFKGLVLIAFSQYLQKCSYDEHAKLVQEVTDF AKTCVADESAANCDKSLHTLFGDKLCAIPNLRENYGELADCCTKQEPERNECFLQHKDDNPSLPPFERPEAEAMC TSFKENPTTFMGHYLHEVARRHPYFYAPELLYYAEQYNEILTQCCAEADKESCLTPKLDGVKEKALVSSVRQRMK CSSMQKFGERAFKAWAVARLSQTFPNADFAEITKLATDLTKVNKECCHGDLLECADDRAELAKYMCENQATISSK LQTCCDKPLLKKAHCLSEVEHDTMPADLPAIAADFVEDQEVCKNYAEAKDVFLGTFLYEYSRRHPDYSVSLLLRL AKKYEATLEKCCAEANPPACYGTVLAEFQPLVEEPKNLVKTNCDLYEKLGEYGFQNAILVRYTQKAPQVSTPTLV EAARNLGRVGTKCCTLPEDQRLPCVEDYLSAILNRVCLLHEKTPVSEHVTKCCSGSLVERRPCFSALTVDETYVPKEFKAETFTFHSDICTLPEKEKQIKKQTALAELVKHKPKATAEQLKTVMDDFAQFLDTCCKAADKDTCFSTEGPNLVTRCKDALAAPTSSSTKKTQLQLEHLLLDLEMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKP LEEVLNLAQSKNFHLRPRDLISNINVIVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIIRTLTHHHHHHH H SEQ ID NO: 16 is the amino acid sequence of an exemplary IL-2-RR (containing two mutations as compared to native IL-2, L18R and S130R). APTSSSTKKTQLQLEHLRLDLQMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKPLEEVLNLAQS KNFHLRPRDLISNINVIVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIIRTLT 4239-112594-02 SEQ ID NO: 17 is the amino acid sequence of an exemplary IL-2-RR MSA. MVSAIVLYVLLAAAAHSAFARGVFRREAHKSEIAHRYNDLGEQHFKGLVLIAFSQYLQKCSYDEHAKLVQEVTDF AKTCVADESAANCDKSLHTLFGDKLCAIPNLRENYGELADCCTKQEPERNECFLQHKDDNPSLPPFERPEAEAMC TSFKENPTTFMGHYLHEVARRHPYFYAPELLYYAEQYNEILTQCCAEADKESCLTPKLDGVKEKALVSSVRQRMK CSSMQKFGERAFKAWAVARLSQTFPNADFAEITKLATDLTKVNKECCHGDLLECADDRAELAKYMCENQATISSK LQTCCDKPLLKKAHCLSEVEHDTMPADLPAIAADFVEDQEVCKNYAEAKDVFLGTFLYEYSRRHPDYSVSLLLRL AKKYEATLEKCCAEANPPACYGTVLAEFQPLVEEPKNLVKTNCDLYEKLGEYGFQNAILVRYTQKAPQVSTPTLV EAARNLGRVGTKCCTLPEDQRLPCVEDYLSAILNRVCLLHEKTPVSEHVTKCCSGSLVERRPCFSALTVDETYVP KEFKAETFTFHSDICTLPEKEKQIKKQTALAELVKHKPKATAEQLKTVMDDFAQFLDTCCKAADKDTCFSTEGPN LVTRCKDALAAPTSSSTKKTQLQLEHLRLDLQMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKP LEEVLNLAQSKNFHLRPRDLISNINVIVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIIRTLTHHHHHHH H SEQ ID NO: 18 is the amino acid sequence of an exemplary IL-2-R (containing one mutation as compared to native IL-2, S130R). APTSSSTKKTQLQLEHLLLDLQMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKPLEEVLNLAQS KNFHLRPRDLISNINVIVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIIRTLT SEQ ID NO: 19 is the amino acid sequence of an exemplary IL-2-R MSA.MVSAIVLYVLLAAAAHSAFARGVFRREAHKSEIAHRYNDLGEQHFKGLVLIAFSQYLQKCSYDEHAKLVQEVTDFAKTCVADESAANCDKSLHTLFGDKLCAIPNLRENYGELADCCTKQEPERNECFLQHKDDNPSLPPFERPEAEAMC TSFKENPTTFMGHYLHEVARRHPYFYAPELLYYAEQYNEILTQCCAEADKESCLTPKLDGVKEKALVSSVRQRMK CSSMQKFGERAFKAWAVARLSQTFPNADFAEITKLATDLTKVNKECCHGDLLECADDRAELAKYMCENQATISSK LQTCCDKPLLKKAHCLSEVEHDTMPADLPAIAADFVEDQEVCKNYAEAKDVFLGTFLYEYSRRHPDYSVSLLLRL AKKYEATLEKCCAEANPPACYGTVLAEFQPLVEEPKNLVKTNCDLYEKLGEYGFQNAILVRYTQKAPQVSTPTLV EAARNLGRVGTKCCTLPEDQRLPCVEDYLSAILNRVCLLHEKTPVSEHVTKCCSGSLVERRPCFSALTVDETYVP KEFKAETFTFHSDICTLPEKEKQIKKQTALAELVKHKPKATAEQLKTVMDDFAQFLDTCCKAADKDTCFSTEGPN LVTRCKDALAAPTSSSTKKTQLQLEHLLLDLQMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKP LEEVLNLAQSKNFHLRPRDLISNINVIVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIIRTLTHHHHHHH H SEQ ID NO: 20 is the amino acid sequence of an exemplary IL-2-RER (containing three mutations as compared to native IL-2, L18R, Q22E, and S130R). APTSSSTKKTQLQLEHLRLDLEMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKPLEEVLNLAQSKNFHLRPRDLISNINVIVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIIRTLTSEQ ID NO: 21 is the amino acid sequence of an exemplary IL-2-RER MSA. MVSAIVLYVLLAAAAHSAFARGVFRREAHKSEIAHRYNDLGEQHFKGLVLIAFSQYLQKCSYDEHAKLVQEVTDF AKTCVADESAANCDKSLHTLFGDKLCAIPNLRENYGELADCCTKQEPERNECFLQHKDDNPSLPPFERPEAEAMCTSFKENPTTFMGHYLHEVARRHPYFYAPELLYYAEQYNEILTQCCAEADKESCLTPKLDGVKEKALVSSVRQRMKCSSMQKFGERAFKAWAVARLSQTFPNADFAEITKLATDLTKVNKECCHGDLLECADDRAELAKYMCENQATISSK LQTCCDKPLLKKAHCLSEVEHDTMPADLPAIAADFVEDQEVCKNYAEAKDVFLGTFLYEYSRRHPDYSVSLLLRL AKKYEATLEKCCAEANPPACYGTVLAEFQPLVEEPKNLVKTNCDLYEKLGEYGFQNAILVRYTQKAPQVSTPTLV EAARNLGRVGTKCCTLPEDQRLPCVEDYLSAILNRVCLLHEKTPVSEHVTKCCSGSLVERRPCFSALTVDETYVP KEFKAETFTFHSDICTLPEKEKQIKKQTALAELVKHKPKATAEQLKTVMDDFAQFLDTCCKAADKDTCFSTEGPN LVTRCKDALAAPTSSSTKKTQLQLEHLRLDLEMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKP LEEVLNLAQSKNFHLRPRDLISNINVIVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIIRTLTHHHHHHH H 4239-112594-02 SEQ ID NO: 22 is the amino acid sequence of an exemplary human H9 IL-2 (H9 contains 5 mutations (L80F, R81D, L85V, I86V, and I92F) compared to wild-type IL-2, indicated in bold). APTSSSTKKTQLQLEHLLLDLQMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKPLEEVLNLAQS KNFHFDPRDVVSNINVFVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIISTLT SEQ ID NO: 23 is the amino acid sequence of an exemplary H9 MSA. MVSAIVLYVLLAAAAHSAFARGVFRREAHKSEIAHRYNDLGEQHFKGLVLIAFSQYLQKCSYDEHAKLVQEVTDF AKTCVADESAANCDKSLHTLFGDKLCAIPNLRENYGELADCCTKQEPERNECFLQHKDDNPSLPPFERPEAEAMC TSFKENPTTFMGHYLHEVARRHPYFYAPELLYYAEQYNEILTQCCAEADKESCLTPKLDGVKEKALVSSVRQRMK CSSMQKFGERAFKAWAVARLSQTFPNADFAEITKLATDLTKVNKECCHGDLLECADDRAELAKYMCENQATISSK LQTCCDKPLLKKAHCLSEVEHDTMPADLPAIAADFVEDQEVCKNYAEAKDVFLGTFLYEYSRRHPDYSVSLLLRL AKKYEATLEKCCAEANPPACYGTVLAEFQPLVEEPKNLVKTNCDLYEKLGEYGFQNAILVRYTQKAPQVSTPTLV EAARNLGRVGTKCCTLPEDQRLPCVEDYLSAILNRVCLLHEKTPVSEHVTKCCSGSLVERRPCFSALTVDETYVP KEFKAETFTFHSDICTLPEKEKQIKKQTALAELVKHKPKATAEQLKTVMDDFAQFLDTCCKAADKDTCFSTEGPN LVTRCKDALAAPTSSSTKKTQLQLEHLLLDLQMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKP LEEVLNLAQSKNFHFDPRDVVSNINVFVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIISTLTHHHHHHH H SEQ ID NO: 24 is the amino acid sequence of an exemplary H9-ET (Q22E and Q126T on H9 background). APTSSSTKKTQLQLEHLLLDLEMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKPLEEVLNLAQS KNFHFDPRDVVSNINVFVLELKGSETTFMCEYADETATIVEFLNRWITFCTSIISTLT SEQ ID NO: 25 is the amino acid sequence of an exemplary H9-ET MSA. MVSAIVLYVLLAAAAHSAFARGVFRREAHKSEIAHRYNDLGEQHFKGLVLIAFSQYLQKCSYDEHAKLVQEVTDF AKTCVADESAANCDKSLHTLFGDKLCAIPNLRENYGELADCCTKQEPERNECFLQHKDDNPSLPPFERPEAEAMC TSFKENPTTFMGHYLHEVARRHPYFYAPELLYYAEQYNEILTQCCAEADKESCLTPKLDGVKEKALVSSVRQRMK CSSMQKFGERAFKAWAVARLSQTFPNADFAEITKLATDLTKVNKECCHGDLLECADDRAELAKYMCENQATISSK LQTCCDKPLLKKAHCLSEVEHDTMPADLPAIAADFVEDQEVCKNYAEAKDVFLGTFLYEYSRRHPDYSVSLLLRL AKKYEATLEKCCAEANPPACYGTVLAEFQPLVEEPKNLVKTNCDLYEKLGEYGFQNAILVRYTQKAPQVSTPTLV EAARNLGRVGTKCCTLPEDQRLPCVEDYLSAILNRVCLLHEKTPVSEHVTKCCSGSLVERRPCFSALTVDETYVP KEFKAETFTFHSDICTLPEKEKQIKKQTALAELVKHKPKATAEQLKTVMDDFAQFLDTCCKAADKDTCFSTEGPN LVTRCKDALAAPTSSSTKKTQLQLEHLLLDLEMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKP LEEVLNLAQSKNFHFDPRDVVSNINVFVLELKGSETTFMCEYADETATIVEFLNRWITFCTSIISTLTHHHHHHH H SEQ ID NO: 26 is the amino acid sequence of an exemplary H9-RT (L18R and Q126T on H9 background). APTSSSTKKTQLQLEHLRLDLQMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKPLEEVLNLAQS KNFHFDPRDVVSNINVFVLELKGSETTFMCEYADETATIVEFLNRWITFCTSIISTLT SEQ ID NO: 27 is the amino acid sequence of an exemplary H9-RT MSA. MVSAIVLYVLLAAAAHSAFARGVFRREAHKSEIAHRYNDLGEQHFKGLVLIAFSQYLQKCSYDEHAKLVQEVTDF AKTCVADESAANCDKSLHTLFGDKLCAIPNLRENYGELADCCTKQEPERNECFLQHKDDNPSLPPFERPEAEAMC TSFKENPTTFMGHYLHEVARRHPYFYAPELLYYAEQYNEILTQCCAEADKESCLTPKLDGVKEKALVSSVRQRMK CSSMQKFGERAFKAWAVARLSQTFPNADFAEITKLATDLTKVNKECCHGDLLECADDRAELAKYMCENQATISSK LQTCCDKPLLKKAHCLSEVEHDTMPADLPAIAADFVEDQEVCKNYAEAKDVFLGTFLYEYSRRHPDYSVSLLLRL AKKYEATLEKCCAEANPPACYGTVLAEFQPLVEEPKNLVKTNCDLYEKLGEYGFQNAILVRYTQKAPQVSTPTLV 4239-112594-02 EAARNLGRVGTKCCTLPEDQRLPCVEDYLSAILNRVCLLHEKTPVSEHVTKCCSGSLVERRPCFSALTVDETYVP KEFKAETFTFHSDICTLPEKEKQIKKQTALAELVKHKPKATAEQLKTVMDDFAQFLDTCCKAADKDTCFSTEGPN LVTRCKDALAAPTSSSTKKTQLQLEHLRLDLQMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKP LEEVLNLAQSKNFHFDPRDVVSNINVFVLELKGSETTFMCEYADETATIVEFLNRWITFCTSIISTLTHHHHHHH H SEQ ID NO: 28 is the amino acid sequence of an exemplary H9-TR (Q126T and S130R on H9 background). APTSSSTKKTQLQLEHLLLDLQMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKPLEEVLNLAQSKNFHFDPRDVVSNINVFVLELKGSETTFMCEYADETATIVEFLNRWITFCTSIIRTLTSEQ ID NO: 29 is the amino acid sequence of an exemplary H9-TR MSA. MVSAIVLYVLLAAAAHSAFARGVFRREAHKSEIAHRYNDLGEQHFKGLVLIAFSQYLQKCSYDEHAKLVQEVTDF AKTCVADESAANCDKSLHTLFGDKLCAIPNLRENYGELADCCTKQEPERNECFLQHKDDNPSLPPFERPEAEAMC TSFKENPTTFMGHYLHEVARRHPYFYAPELLYYAEQYNEILTQCCAEADKESCLTPKLDGVKEKALVSSVRQRMK CSSMQKFGERAFKAWAVARLSQTFPNADFAEITKLATDLTKVNKECCHGDLLECADDRAELAKYMCENQATISSK LQTCCDKPLLKKAHCLSEVEHDTMPADLPAIAADFVEDQEVCKNYAEAKDVFLGTFLYEYSRRHPDYSVSLLLRL AKKYEATLEKCCAEANPPACYGTVLAEFQPLVEEPKNLVKTNCDLYEKLGEYGFQNAILVRYTQKAPQVSTPTLV EAARNLGRVGTKCCTLPEDQRLPCVEDYLSAILNRVCLLHEKTPVSEHVTKCCSGSLVERRPCFSALTVDETYVP KEFKAETFTFHSDICTLPEKEKQIKKQTALAELVKHKPKATAEQLKTVMDDFAQFLDTCCKAADKDTCFSTEGPN LVTRCKDALAAPTSSSTKKTQLQLEHLLLDLQMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKP LEEVLNLAQSKNFHFDPRDVVSNINVFVLELKGSETTFMCEYADETATIVEFLNRWITFCTSIIRTLTHHHHHHH H SEQ ID NO: 30 is the amino acid sequence of an exemplary H9-ER (Q22E and S130R on H9 background). APTSSSTKKTQLQLEHLLLDLEMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKPLEEVLNLAQS KNFHFDPRDVVSNINVFVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIIRTLT SEQ ID NO: 31 is the amino acid sequence of an exemplary H9-ER MSA. MVSAIVLYVLLAAAAHSAFARGVFRREAHKSEIAHRYNDLGEQHFKGLVLIAFSQYLQKCSYDEHAKLVQEVTDF AKTCVADESAANCDKSLHTLFGDKLCAIPNLRENYGELADCCTKQEPERNECFLQHKDDNPSLPPFERPEAEAMC TSFKENPTTFMGHYLHEVARRHPYFYAPELLYYAEQYNEILTQCCAEADKESCLTPKLDGVKEKALVSSVRQRMK CSSMQKFGERAFKAWAVARLSQTFPNADFAEITKLATDLTKVNKECCHGDLLECADDRAELAKYMCENQATISSK LQTCCDKPLLKKAHCLSEVEHDTMPADLPAIAADFVEDQEVCKNYAEAKDVFLGTFLYEYSRRHPDYSVSLLLRL AKKYEATLEKCCAEANPPACYGTVLAEFQPLVEEPKNLVKTNCDLYEKLGEYGFQNAILVRYTQKAPQVSTPTLV EAARNLGRVGTKCCTLPEDQRLPCVEDYLSAILNRVCLLHEKTPVSEHVTKCCSGSLVERRPCFSALTVDETYVP KEFKAETFTFHSDICTLPEKEKQIKKQTALAELVKHKPKATAEQLKTVMDDFAQFLDTCCKAADKDTCFSTEGPN LVTRCKDALAAPTSSSTKKTQLQLEHLLLDLEMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKPLEEVLNLAQSKNFHFDPRDVVSNINVFVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIIRTLTHHHHHHHH SEQ ID NO: 32 is the amino acid sequence of an exemplary H9-RR (L18R and S130R on H9 background). APTSSSTKKTQLQLEHLRLDLQMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKPLEEVLNLAQS KNFHFDPRDVVSNINVFVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIIRTLT 4239-112594-02 SEQ ID NO: 33 is the amino acid sequence of an exemplary H9-RR MSA. MVSAIVLYVLLAAAAHSAFARGVFRREAHKSEIAHRYNDLGEQHFKGLVLIAFSQYLQKCSYDEHAKLVQEVTDF AKTCVADESAANCDKSLHTLFGDKLCAIPNLRENYGELADCCTKQEPERNECFLQHKDDNPSLPPFERPEAEAMC TSFKENPTTFMGHYLHEVARRHPYFYAPELLYYAEQYNEILTQCCAEADKESCLTPKLDGVKEKALVSSVRQRMK CSSMQKFGERAFKAWAVARLSQTFPNADFAEITKLATDLTKVNKECCHGDLLECADDRAELAKYMCENQATISSK LQTCCDKPLLKKAHCLSEVEHDTMPADLPAIAADFVEDQEVCKNYAEAKDVFLGTFLYEYSRRHPDYSVSLLLRL AKKYEATLEKCCAEANPPACYGTVLAEFQPLVEEPKNLVKTNCDLYEKLGEYGFQNAILVRYTQKAPQVSTPTLV EAARNLGRVGTKCCTLPEDQRLPCVEDYLSAILNRVCLLHEKTPVSEHVTKCCSGSLVERRPCFSALTVDETYVP KEFKAETFTFHSDICTLPEKEKQIKKQTALAELVKHKPKATAEQLKTVMDDFAQFLDTCCKAADKDTCFSTEGPN LVTRCKDALAAPTSSSTKKTQLQLEHLRLDLQMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKP LEEVLNLAQSKNFHFDPRDVVSNINVFVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIIRTLTHHHHHHH H SEQ ID NO: 34 is the amino acid sequence of an exemplary H9-R (S130R on H9 background). APTSSSTKKTQLQLEHLLLDLQMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKPLEEVLNLAQS KNFHFDPRDVVSNINVFVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIIRTLT SEQ ID NO: 35 is the amino acid sequence of an exemplary H9-R MSA.MVSAIVLYVLLAAAAHSAFARGVFRREAHKSEIAHRYNDLGEQHFKGLVLIAFSQYLQKCSYDEHAKLVQEVTDFAKTCVADESAANCDKSLHTLFGDKLCAIPNLRENYGELADCCTKQEPERNECFLQHKDDNPSLPPFERPEAEAMC TSFKENPTTFMGHYLHEVARRHPYFYAPELLYYAEQYNEILTQCCAEADKESCLTPKLDGVKEKALVSSVRQRMK CSSMQKFGERAFKAWAVARLSQTFPNADFAEITKLATDLTKVNKECCHGDLLECADDRAELAKYMCENQATISSK LQTCCDKPLLKKAHCLSEVEHDTMPADLPAIAADFVEDQEVCKNYAEAKDVFLGTFLYEYSRRHPDYSVSLLLRL AKKYEATLEKCCAEANPPACYGTVLAEFQPLVEEPKNLVKTNCDLYEKLGEYGFQNAILVRYTQKAPQVSTPTLV EAARNLGRVGTKCCTLPEDQRLPCVEDYLSAILNRVCLLHEKTPVSEHVTKCCSGSLVERRPCFSALTVDETYVP KEFKAETFTFHSDICTLPEKEKQIKKQTALAELVKHKPKATAEQLKTVMDDFAQFLDTCCKAADKDTCFSTEGPN LVTRCKDALAAPTSSSTKKTQLQLEHLLLDLQMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKP LEEVLNLAQSKNFHFDPRDVVSNINVFVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIIRTLTHHHHHHH H SEQ ID NO: 36 is the amino acid sequence of an exemplary H9-RER (L18R, Q22E, and S130R on H9 background). APTSSSTKKTQLQLEHLRLDLEMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKPLEEVLNLAQSKNFHFDPRDVVSNINVFVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIIRTLTSEQ ID NO: 37 is the amino acid sequence of an exemplary H9-RER MSA. MVSAIVLYVLLAAAAHSAFARGVFRREAHKSEIAHRYNDLGEQHFKGLVLIAFSQYLQKCSYDEHAKLVQEVTDF AKTCVADESAANCDKSLHTLFGDKLCAIPNLRENYGELADCCTKQEPERNECFLQHKDDNPSLPPFERPEAEAMCTSFKENPTTFMGHYLHEVARRHPYFYAPELLYYAEQYNEILTQCCAEADKESCLTPKLDGVKEKALVSSVRQRMKCSSMQKFGERAFKAWAVARLSQTFPNADFAEITKLATDLTKVNKECCHGDLLECADDRAELAKYMCENQATISSK LQTCCDKPLLKKAHCLSEVEHDTMPADLPAIAADFVEDQEVCKNYAEAKDVFLGTFLYEYSRRHPDYSVSLLLRL AKKYEATLEKCCAEANPPACYGTVLAEFQPLVEEPKNLVKTNCDLYEKLGEYGFQNAILVRYTQKAPQVSTPTLV EAARNLGRVGTKCCTLPEDQRLPCVEDYLSAILNRVCLLHEKTPVSEHVTKCCSGSLVERRPCFSALTVDETYVP KEFKAETFTFHSDICTLPEKEKQIKKQTALAELVKHKPKATAEQLKTVMDDFAQFLDTCCKAADKDTCFSTEGPN LVTRCKDALAAPTSSSTKKTQLQLEHLRLDLEMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKP LEEVLNLAQSKNFHFDPRDVVSNINVFVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIIRTLTHHHHHHH H 4239-112594-02 DETAILED DESCRIPTION I. Introduction Controlling the actions of IL-2 is of importance in developing IL-2 as an effective immunotherapeutic agent. Simultaneous mutation of four IL-2 residues at the IL-2-γcinterface (specifically L18R, Q22E, Q126T, and S130R) profoundly inhibits IL-2 signaling and function, including NK cytolytic activity and proliferation (Mitra et al., Immunity (2015) 42:826-38). IL-2 with the single amino acid change Q126T is a partial agonist (Mo et al., Nature (2021) 597:544-48). As disclosed herein, an array of IL-2 variants was generated with either one, two, or three mutations at positions 18, 22, 126, and 130. A list of these variants is shown in Table 1. IL-2-ET (SEQ ID NO: 8) exhibited unexpected properties. In particular, IL-2-ET was distinctive in preferentially expanding Treg cells when injected into mice or when cultured with human PBMCs in vitro, and in addition, in expanding activated CD8+T cells while maintaining a T stem-like phenotype. These findings indicate that IL-2-ET has clinical relevance in autoimmune disease where expansion of Treg numbers / function is desired. IL-2- ET also unexpectedly induced stemness of cultured CD8+T cells, an extremely important feature for adoptive cell transfer and chimeric antigen receptor (CAR)-T therapies. Surprisingly, IL-2-RER (SEQ ID NO: 20) induced elevated levels of pSTAT5 as compared to IL-2. Previously, no mutant had been observed to exhibit this property of having a higher Emax for phosphorylation of STAT5 as compared to IL-2. Such a property has utility in boosting T cell responses. II. Abbreviations CAR chimeric antigen receptor DSS dextran sodium sulfate IL-2 interleukin-2 ILC2 type 2 innate lymphoid cells MFI mean fluorescence intensity MSA mouse serum albumin NK natural killer PBMC peripheral blood mononuclear cell pLN pancreatic lymph node SLE systemic lupus erythematosus 4239-112594-02 T1D type 1 diabetes Treg T regulatory WT wild-type III. Summary of Terms Unless otherwise noted, technical terms are used according to conventional usage. Definitions of many common terms in molecular biology may be found in Krebs et al. (eds.), Lewin’s genes XII, published by Jones & Bartlett Learning, 2017. As used herein, the singular forms “a,” “an,” and “the,” refer to both the singular as well as plural, unless the context clearly indicates otherwise. For example, the term “an antigen” includes singular or plural antigens and can be considered equivalent to the phrase “at least one antigen.” As used herein, the term “comprises” means “includes.” It is further to be understood that any and all base sizes or amino acid sizes, and all molecular weight or molecular mass values, given for nucleic acids or polypeptides are approximate, and are provided for descriptive purposes, unless otherwise indicated. Although many methods and materials similar or equivalent to those described herein can be used, particular suitable methods and materials are described herein. In case of conflict, the present specification, including explanations of terms, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting. To facilitate review of the various aspects, the following explanations of terms are provided: Administration: The introduction of a composition into a subject by a chosen route. Administration can be local or systemic. For example, if the chosen route is intravenous, the composition (such as a composition including a disclosed recombinant IL-2 protein) is administered by introducing the composition into a vein of the subject. Exemplary routes of administration include, but are not limited to, oral, injection (such as subcutaneous, intramuscular, intradermal, intraperitoneal, and intravenous), sublingual, rectal, transdermal (for example, topical), intranasal, vaginal, and inhalation routes. Amino acid substitution: The replacement of one amino acid in a polypeptide with a different amino acid. Autoimmune disorder: A disorder in which the immune system produces an immune response (for example, a B cell or a T cell response) against an endogenous antigen, with consequent injury to tissues. For example, rheumatoid arthritis is an autoimmune disorder, as are Hashimoto’s thyroiditis, pernicious anemia, Addison’s disease, type I diabetes, systemic lupus erythematosus, dermatomyositis, Sjogren’s syndrome, 4239-112594-02 dermatomyositis, lupus erythematosus, multiple sclerosis, myasthenia gravis, Reiter’s syndrome, and Grave’s disease, colitis including ulcerative colitis, among others. Cancer: A malignant tumor or neoplasm characterized by abnormal or uncontrolled cell growth. Other features often associated with cancer include metastasis, interference with the normal functioning of neighboring cells, release of cytokines or other secretory products at abnormal levels, suppression or aggravation of inflammatory or immunological response, invasion of surrounding or distant tissues or organs, such as lymph nodes, etc. “Metastatic disease” refers to cancer cells that have left the original tumor site and migrated to other parts of the body, for example via the bloodstream or lymph system. Cancer includes, for example, malignancies of the various organ systems, including those affecting the lung, breast, thyroid, lymph glands and lymphoid tissue, gastrointestinal organs, and the genitourinary tract, as well as to adenocarcinomas which are generally considered to include malignancies such as most colon cancers, renal-cell carcinoma, prostate cancer and / or testicular tumors, non- small cell carcinoma of the lung, cancer of the small intestine and cancer of the esophagus. Non-limiting types of cancer (for example, that can be treated using the methods provided herein) include solid cancers, such as breast carcinomas (e.g. lobular and duct carcinomas), sarcomas, carcinomas of the lung (e.g., non-small cell carcinoma, large cell carcinoma, squamous carcinoma, and adenocarcinoma), mesothelioma of the lung, colorectal adenocarcinoma, head and neck cancers, stomach carcinoma, prostatic adenocarcinoma, ovarian carcinoma (such as serous cystadenocarcinoma and mucinous cystadenocarcinoma), ovarian germ cell tumors, testicular carcinomas and germ cell tumors, pancreatic adenocarcinoma, biliary adenocarcinoma, hepatocellular carcinoma, bladder carcinoma (including, for instance, transitional cell carcinoma, adenocarcinoma, and squamous carcinoma), renal cell adenocarcinoma, endometrial carcinomas (including, e.g., adenocarcinomas and mixed Mullerian tumors (carcinosarcomas)), carcinomas of the endocervix, ectocervix, and vagina (such as adenocarcinoma and squamous carcinoma of each of same), cancers of the skin (e.g., squamous cell carcinoma, basal cell carcinoma, malignant melanoma, skin appendage tumors, Kaposi sarcoma, cutaneous lymphoma, skin adnexal tumors and various types of sarcomas and Merkel cell carcinoma), esophageal carcinoma, carcinomas of the nasopharynx and oropharynx (including squamous carcinoma and adenocarcinomas of same), salivary gland carcinomas, brain and central nervous system tumors (including, for example, tumors of glial, neuronal, and meningeal origin), tumors of peripheral nerve, soft tissue sarcomas and sarcomas of bone and cartilage, and lymphatic 4239-112594-02 tumors (including B-cell and T- cell malignant lymphoma). In one example, the cancer is an adenocarcinoma. In one example, the tumor is a glioblastoma. Additional types of cancer (for example, that can be treated using the methods provided herein) include liquid cancers, such as a lymphatic cancer, a white blood cell cancer, or other type of leukemia. In a specific example, the cancer treated is a tumor of the blood, such as a leukemia (for example acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL), acute myelogenous leukemia (AML), chronic myelogenous leukemia (CML), hairy cell leukemia (HCL), T-cell prolymphocytic leukemia (T-PLL), large granular lymphocytic leukemia , and adult T-cell leukemia), lymphomas (such as Hodgkin’s lymphoma and non-Hodgkin’s lymphoma), and myelomas). Chimeric antigen receptor (CAR): A chimeric molecule that includes an antigen- binding portion (such as a single domain antibody or scFv) and a signaling domain, such as a signaling domain from a T cell receptor (e.g., CD3ζ). Typically, CARs include an antigen- binding portion, a transmembrane domain, and an intracellular domain. The intracellular domain typically includes a signaling chain having an immunoreceptor tyrosine-based activation motif (ITAM), such as CD3ζ or FcεRIγ. In some instances, the intracellular domain also includes the intracellular portion of at least one additional co-stimulatory domain, such as CD28, 4-1BB (CD137), ICOS, OX40 (CD134), CD27 and / or DAP10. In the context of cancer immunotherapy, the antigen-binding portion typically targets and binds cancer antigens. Chimeric antigen receptor T cell (CAR T-cell): A T cell expressing a CAR, and has antigen specificity determined by the antibody-derived targeting domain of the CAR. Methods of making CAR T-cells are known (see, e.g., Park et al., Trends Biotechnol., 29:550-557, 2011; Grupp et al., N Engl J Med., 368:1509-1518, 2013; Han et al., J. Hematol Oncol., 6:47, 2013; PCT Pubs. WO2012 / 079000, WO2013 / 059593; and U.S. Pub. 2012 / 0213783). Control: A reference standard. In some aspects, the control is a negative control sample obtained from a healthy patient. In other aspects, the control is a positive control sample. In still other aspects, the control is a historical control or standard reference value or range of values (such as a previously tested control sample, such as a group of patients with known prognosis or outcome, or group of samples that represent baseline or normal values). A difference between a test sample and a control can be an increase or conversely a decrease. The difference can be a qualitative difference or a quantitative difference, for 4239-112594-02 example, a statistically significant difference. In some examples, a difference is an increase or decrease, relative to a control, of at least about 5%, such as at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 100%, at least about 150%, at least about 200%, at least about 250%, at least about 300%, at least about 350%, at least about 400%, at least about 500%, or greater than 500%. Expression: Transcription or translation of a nucleic acid sequence. For example, a gene is expressed when its DNA is transcribed into an RNA or RNA fragment, which in some examples is processed to become mRNA. A gene may also be expressed when its mRNA is translated into an amino acid sequence, such as a protein or a protein fragment. In a particular example, a heterologous gene is expressed when it is transcribed into an RNA. In another example, a heterologous gene is expressed when its RNA is translated into an amino acid sequence. The term “expression” is used herein to denote either transcription or translation. Regulation of expression can include controls on transcription, translation, RNA transport and processing, degradation of intermediary molecules such as mRNA, or through activation, inactivation, compartmentalization or degradation of specific protein molecules after they are produced. Expression control sequences: Nucleic acid sequences that regulate the expression of a heterologous nucleic acid sequence to which it is operatively linked. Expression control sequences are operatively linked to a nucleic acid sequence when the expression control sequences control and regulate the transcription and, as appropriate, translation of the nucleic acid sequence. Thus, expression control sequences can include appropriate promoters, enhancers, transcription terminators, a start codon (ATG) in front of a protein-encoding gene, splicing signals for introns, maintenance of the correct reading frame of that gene to permit proper translation of mRNA, and stop codons. The term “control sequences” is intended to include, at a minimum, components whose presence can influence expression, and can also include additional components whose presence is advantageous, for example, leader sequences and fusion partner sequences. Expression control sequences can include a promoter. A promoter is a minimal sequence sufficient to direct transcription. Also included are those promoter elements which are sufficient to render promoter-dependent gene expression controllable for cell-type specific, tissue-specific, or inducible by external signals or agents; such elements may be located in the 5' or 3' regions of the gene. Both constitutive and inducible promoters are included. For example, when cloning in bacterial systems, inducible 4239-112594-02 promoters such as pL of bacteriophage lambda, plac, ptrp, ptac (ptrp-lac hybrid promoter) and the like may be used. In one aspect, when cloning in mammalian cell systems, promoters derived from the genome of mammalian cells (such as metallothionein promoter) or from mammalian viruses (such as the retrovirus long terminal repeat; the adenovirus late promoter; the vaccinia virus 7.5K promoter) can be used. Promoters produced by recombinant DNA or synthetic techniques may also be used to provide for transcription of the nucleic acid sequences. A polynucleotide can be inserted into an expression vector that contains a promoter sequence which facilitates the efficient transcription of the inserted genetic sequence of the host. The expression vector typically contains an origin of replication, a promoter, as well as specific nucleic acid sequences that allow phenotypic selection of the transformed cells. Expression vector: A vector comprising a recombinant polynucleotide comprising expression control sequences operatively linked to a nucleotide sequence to be expressed. An expression vector comprises sufficient cis-acting elements for expression; other elements for expression can be supplied by the host cell or in an in vitro expression system. Non-limiting examples of expression vectors include cosmids, plasmids (e.g., naked or contained in liposomes) and viruses (e.g., lentiviruses, retroviruses, adenoviruses, and adeno-associated viruses) that incorporate the recombinant polynucleotide. Fusion protein: A single polypeptide chain including the sequence of two or more heterologous proteins, sometimes connected by a peptide linker. Reference to a first protein “fused” to a second protein indicates that the first and second proteins are contained within a single contiguous polypeptide chain. The first and second protein may be directly linked (for example, the C-terminus of the first protein is linked to the N-terminus of the second protein by a peptide bond), or indirectly linked (for example, the C-terminus of the first protein is directly linked to the N-terminus of a peptide linker by a peptide bond, and the C-terminus of the peptide linker is directly linked to the N-terminus of the second protein by a peptide bond). Heterologous: A heterologous polypeptide or polynucleotide refers to a polypeptide or polynucleotide derived from a different source or species. Host cells: Cells in which a vector can be propagated and its DNA expressed. The cell may be prokaryotic or eukaryotic. The term also includes any progeny of the subject host cell. It is understood that all progeny may not be identical to the parental cell since there may be mutations that occur during replication. However, such progeny are included when the term “host cell” is used. 4239-112594-02 IL-2 mutein: An IL-2 protein that has one or more amino acid substitutions compared to wild-type IL-2 protein (that is, a recombinant IL-2 protein). Interleukin 2 (IL-2): A pleiotropic cytokine that is primarily produced by activated CD4+T cells. IL-2 plays an important role as a growth factor that induces the proliferation of CD8+and CD4+T cells. It also has many other biological roles including the induction of the proliferation of natural killer cells (NK), the increment of cytolytic activity, the promotion of antibody production and B cell proliferation. Furthermore, it is essential for the induction of activation-induced cell death (AICD), a role that is vital for homeostasis and for the elimination of putative and dangerous self-reactive cells. IL-2 also contributes to the development of CD4+FOXP3+regulatory T cells, which act as cell suppressors in the cell tolerance system. IL-2 exerts its actions via binding to various types of IL-2 receptor (IL-2R), notably monomeric, dimeric, and trimeric IL-2Rs. Monomeric IL-2Rs, comprising IL-2Rα (CD25), are usually cell membrane associated but also exist in soluble form and bind IL-2 with a low- affinity Kd of ~10-8M. Conversely, both dimeric and trimeric IL-2Rs lead to a downstream signal on binding to IL-2. Dimeric IL-2Rs comprise IL-2Rβ (CD122) and IL-2Rγ (also known as common γ-chain (γc) or CD132), whereas trimeric IL-2Rs comprise CD25, CD122, and γc. Dimeric IL-2Rs are referred to as intermediate-affinity (Kd ~10-9M) and trimeric IL- 2Rs as high-affinity (Kd ~10-11M) IL-2Rs. On triggering of IL-2R, signal transduction occurs via three major pathways, involving: (i) Janus kinase (JAK)-signal transducer and activator of transcription (STAT); (ii) phosphoinositide 3-kinase (PI3K)-AKT; and (iii) mitogen-activated protein kinase (MAPK). The stimulatory effect of wild-type IL-2 on T effector (Teff) and NK cells motivated trials of high-dose IL-2 for the treatment of cancer, with recombinant human IL-2 (Aldesleukin) becoming the first US Food and Drug Administration approved immunotherapy for the treatment of metastatic renal cell carcinoma (RCC) and metastatic melanoma in 1992 and 1998, respectively. In the context of adoptive cell transfer, IL-2 administration to human patients can enhance CAR-T engraftment, persistence, and functionality. However, the stimulatory effects of high-dose IL-2 on Treg cells, which dampen immune responses against self-antigens including certain tumor antigens, as well as the considerable adverse side effects of IL-2 at high doses due to vascular leak syndrome limited its efficacy in cancer. 4239-112594-02 Mature human IL-2 occurs as a 133 amino acid sequence (not including its signal peptide, which consists of an additional 20 N-terminal amino acids), as described in Fujita et al., Proc Natl Acad Sci USA, 80, 7437-7441 (1983). The amino acid sequence of mature human IL-2 is provided herein as SEQ ID NO: 6. Unless indicated otherwise by context, IL- 2 amino acid positions are according to the reference IL-2 sequence provided as SEQ ID NO: 6. IL-2 sequences are also publicly available, for example the pre-cursor IL-2 protein sequence (including signal peptide) is provided as GenBank accession number NP_000577.2, incorporated by reference herein as present in the database on October 15, 2024. H9 IL-2 is a recombinant form of IL-2 with increased binding affinity for IL-2Rβ. This mutant contains the L80F, R81D, L85V, I86V and I92F substitutions (Levin et al., Nature 484(7395):529-533, 2012). Immune response: A response of a cell of the immune system, such as a B cell, T cell, or macrophage, to a stimulus. In one aspect, the response is specific for a particular antigen (an “antigen-specific response”). Linked: The term “linked” means joined together, either directly or indirectly. For example, a first moiety may be covalently or noncovalently (e.g., electrostatically) linked to a second moiety. This includes, but is not limited to, covalently bonding one molecule to another molecule, noncovalently bonding one molecule to another (e.g. electrostatically bonding), non-covalently bonding one molecule to another molecule by hydrogen bonding, non-covalently bonding one molecule to another molecule by van der Waals forces, and any and all combinations of such couplings. Indirect attachment is possible, such as by using a “linker”. In several aspects, linked components are associated in a chemical or physical manner so that the components are not freely dispersible from one another, at least until contacting a cell, such as an immune cell. Linker: One or more molecules or groups of atoms positioned between two moieties. Typically, linkers are bifunctional, i.e., the linker includes a functional group at each end, wherein the functional groups are used to couple the linker to the two moieties. The two functional groups may be the same, i.e., a homobifunctional linker, or different, i.e., a heterobifunctional linker. In several aspects, a peptide linker can be used to link the C- terminus of a first protein to the N-terminus of a second protein. Nucleic acid molecule: A polymeric form of nucleotides, which may include both sense and anti-sense strands of RNA, cDNA, genomic DNA, and synthetic forms and mixed polymers of the above. A nucleotide refers to a ribonucleotide, deoxynucleotide or a 4239-112594-02 modified form of either type of nucleotide. The term “nucleic acid molecule” as used herein is synonymous with “nucleic acid” and “polynucleotide.” A nucleic acid molecule is usually at least 10 bases in length, unless otherwise specified. The term includes single- and double-stranded forms of DNA. A polynucleotide may include either or both naturally occurring and modified nucleotides linked together by naturally occurring and / or non-naturally occurring nucleotide linkages. “cDNA” refers to a DNA that is complementary or identical to an mRNA, in either single stranded or double stranded form. “Encoding” refers to the inherent property of specific sequences of nucleotides in a polynucleotide, such as a gene, a cDNA, or an mRNA, to serve as templates for synthesis of other polymers and macromolecules in biological processes having either a defined sequence of nucleotides (i.e., rRNA, tRNA and mRNA) or a defined sequence of amino acids and the biological properties resulting therefrom. Operably linked: A first nucleic acid sequence is operably linked with a second nucleic acid sequence when the first nucleic acid sequence is placed in a functional relationship with the second nucleic acid sequence. For instance, a promoter is operably linked to a coding sequence if the promoter affects the transcription or expression of the coding sequence. Generally, operably linked nucleic acid sequences are contiguous and, where necessary to join two protein-coding regions, in the same reading frame. Pharmaceutically acceptable carriers: The pharmaceutically acceptable carriers of use are conventional. Remington: The Science and Practice of Pharmacy, 22nded., London, UK: Pharmaceutical Press, 2013, describes compositions and formulations suitable for pharmaceutical delivery of the disclosed agents. In general, the nature of the carrier will depend on the particular mode of administration being employed. For instance, parenteral formulations usually include injectable fluids that include pharmaceutically and physiologically acceptable fluids such as water, physiological saline, balanced salt solutions, aqueous dextrose, glycerol or the like as a vehicle. For solid compositions (e.g., powder, pill, tablet, or capsule forms), conventional non-toxic solid carriers can include, for example, pharmaceutical grades of mannitol, lactose, starch, or magnesium stearate. In addition to biologically neutral carriers, pharmaceutical compositions to be administered can contain minor amounts of non-toxic auxiliary substances, such as wetting or emulsifying agents, added preservatives (such as non-natural preservatives), and pH buffering agents and the like, for example sodium acetate or sorbitan monolaurate. In particular examples, the pharmaceutically acceptable carrier is sterile and suitable for parenteral administration to a subject for example, by injection. In some aspects, 4239-112594-02 the active agent and pharmaceutically acceptable carrier are provided in a unit dosage form such as a pill or in a selected quantity in a vial. Unit dosage forms can include one dosage or multiple dosages (for example, in a vial from which metered dosages of the agents can selectively be dispensed). Protein: Any chain of amino acids, regardless of length or post-translational modification (e.g., glycosylation or phosphorylation). “Protein” applies to amino acid polymers including naturally occurring amino acid polymers and non-naturally occurring amino acid polymers in which one or more amino acid residue is a non-natural amino acid, for example, an artificial chemical mimetic of a corresponding naturally occurring amino acid. A “residue” refers to an amino acid or amino acid mimetic incorporated in a polypeptide by an amide bond or amide bond mimetic. A protein has an amino terminal (N- terminal) end and a carboxy terminal (C-terminal) end. “Protein” is used interchangeably with “polypeptide.” Recombinant: A recombinant nucleic acid or protein is one that has a sequence that is not naturally occurring (e.g., due to selective mutation) or has a sequence that is made by an artificial combination of two otherwise separated segments of sequence. This artificial combination is often accomplished by chemical synthesis or by the artificial manipulation of isolated segments of nucleic acids, for example, by genetic engineering techniques. Sample (or biological sample): A biological specimen containing genomic DNA, RNA (including mRNA), protein, or combinations thereof, obtained from a subject. Examples include, but are not limited to, peripheral blood, tissue, cells, urine, saliva, tissue biopsy, fine needle aspirate, surgical specimen, and autopsy material. Sequence identity: The similarity between amino acid sequences is expressed in terms of the similarity between the sequences, otherwise referred to as sequence identity. Sequence identity is frequently measured in terms of percentage identity; the higher the percentage, the more similar the two sequences are. Homologs, orthologs, or variants of a polypeptide will possess a relatively high degree of sequence identity when aligned using standard methods. Methods of alignment of sequences for comparison are well known in the art. Various programs and alignment algorithms are described in: Smith & Waterman, Adv. Appl. Math. 2:482, 1981; Needleman & Wunsch, J. Mol. Biol.48:443, 1970; Pearson & Lipman, Proc. Natl. Acad. Sci. USA 85:2444, 1988; Higgins & Sharp, Gene, 73:237-44, 1988; Higgins & Sharp, CABIOS 5:151-3, 1989; Corpet et al., Nuc. Acids Res.16:10881-90, 1988; Huang et al. Computer Appls. In the Biosciences 8, 155-65, 1992; and Pearson et al., Meth. Mol. Bio. 4239-112594-02 24:307-31, 1994. Altschul et al., J. Mol. Biol.215:403-10, 1990, presents a detailed consideration of sequence alignment methods and homology calculations. Variants of a polypeptide are typically characterized by possession of at least about 75%, for example, at least about 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity counted over the full-length alignment with the amino acid sequence of interest. Proteins with even greater similarity to the reference sequences will show increasing percentage identities when assessed by this method, such as at least 80%, at least 85%, at least 90%, at least 95%, at least 98%, or at least 99% sequence identity. When less than the entire sequence is being compared for sequence identity, homologs and variants will typically possess at least 80% sequence identity over short windows of 10-20 amino acids and may possess sequence identities of at least 85% or at least 90% or 95% depending on their similarity to the reference sequence. Methods for determining sequence identity over such short windows are available at the NCBI website on the internet. As used herein, reference to “at least 80% identity” (or similar language) refers to “at least 80%, at least 81%, at least 82%, at least 83%, at least 84%, at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or even 100% identity” to a specified reference sequence. As used herein, reference to “at least 90% identity” (or similar language) refers to “at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or even 100% identity” to a specified reference sequence. Small molecule: A molecule, typically with a molecular weight less than about 1000 Daltons, or in some aspects, less than about 500 Daltons, wherein the molecule is capable of modulating, to some measurable extent, an activity of a target molecule. Therapeutically effective amount: The amount of an agent (such as a recombinant IL-2 protein) that alone, or together with one or more additional agents, induces the desired response, such as, for example, treatment of cancer or an autoimmune disease in a subject. When administered to a subject, a dosage will generally be used that will achieve target tissue concentrations that have been shown to achieve a desired in vitro effect. Ideally, a therapeutically effective amount provides a therapeutic effect without causing a substantial cytotoxic effect in the subject. In one example, a desired response is to decrease the size, volume, or number (such as metastases) of tumor tissue in a subject. For example, the agent or agents can decrease the size, volume, or number of tumors by a desired amount, for example by at least 5%, at least 4239-112594-02 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 50%, at least 75%, at least 90%, or at least 95% as compared to a response in the absence of the agent. In another example, a desired response is to reduce symptoms of an autoimmune disease in a subject. For example, the agent or agents can reduce such symptoms by a desired amount, for example by at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 50%, at least 75%, at least 90%, or at least 95% as compared to a response in the absence of the agent. Several preparations disclosed herein are administered in therapeutically effective amounts. A therapeutically effective amount of a recombinant IL-2 protein that is administered to a human or veterinary subject will vary depending upon a number of factors associated with that subject, for example the overall health of the subject. A therapeutically effective amount can be determined by varying the dosage and measuring the resulting therapeutic response, such as the regression of a tumor. Therapeutically effective amounts also can be determined through various in vitro, in vivo or in situ immunoassays. The disclosed agents can be administered in a single dose, or in several doses, as needed to obtain the desired response. However, the therapeutically effective amount can be dependent on the source applied, the subject being treated, the severity and type of the condition being treated, and the manner of administration. T cell: A white blood cell (lymphocyte) that is an important mediator of the immune response. T cells include, but are not limited to, CD4+T cells and CD8+T cells. A CD4+T cell is an immune cell that carries a marker on its surface known as “cluster of differentiation 4” (CD4). These cells, also known as helper T cells, help orchestrate the immune response, including antibody responses as well as killer T cell responses. CD8+T cells carry the “cluster of differentiation 8” (CD8) marker. Activated T cells can be detected by an increase in cell proliferation and / or expression of or secretion of one or more cytokines (such as IL-2, IL-4, IL-6, IFNγ, or TNFα). Activation of CD8+T cells can also be detected by an increase in cytolytic activity in response to an antigen. A regulatory T (Treg) cell is a class of T cell that has a role in maintaining immune system homeostasis by suppressing over-reactive immune responses (Josefowicz et al. Annu. Rev. Immunol.30, 531–564, 2012). Defects in Treg cells lead to autoimmune disorders and immunopathology, whereas certain tumors are enriched with Treg cells that suppress anti- tumor immune responses (Tanaka and Sakaguchi, Cell Res.27, 109–118, 2017). 4239-112594-02 In some examples, a “modified T cell” is a T cell transduced or transformed with a heterologous nucleic acid (such as one or more of the nucleic acids or vectors disclosed herein) or expressing one or more heterologous proteins. The terms “modified T cell” and “transduced T cell” are used interchangeably in some examples herein. Similarly, a “modified Treg cell” is a Treg cell transduced or transformed with a heterologous nucleic acid (such as one or more of the nucleic acids or vectors disclosed herein) or expressing one or more heterologous proteins. Transduced or Transformed: A transformed cell is a cell into which a nucleic acid molecule has been introduced by molecular biology techniques. As used herein, the terms transduction and transformation encompass all techniques by which a nucleic acid molecule might be introduced into such a cell, including transduction or transfection with viral vectors, the use of plasmid vectors, and introduction of DNA by electroporation, lipofection, and particle gun acceleration. Treating, preventing, or ameliorating a disease: “Treating” refers to a therapeutic intervention that ameliorates a sign or symptom of a disease or pathological condition after it has begun to develop, such as a reduction in tumor burden or a decrease in the number or size of metastases. “Ameliorating” refers to the reduction in the number or severity of signs or symptoms of a disease, such as cancer. The beneficial effect can be evidenced, for example, by a delayed onset of clinical symptoms of the disease in a susceptible subject, a reduction in severity of some or all clinical symptoms of the disease, a slower progression of the disease, an improvement in the overall health or well-being of the subject, or by other parameters well known in the art that are specific to the particular disease. “Preventing” a disease refers to inhibiting the full development of a disease. A prophylactic treatment is a treatment administered to a subject who does not exhibit signs of a disease or exhibits only early signs for the purpose of decreasing the risk of developing pathology. Under conditions sufficient for: A phrase that is used to describe any environment that permits a desired activity. Vector: A nucleic acid molecule as introduced into a host cell, thereby producing a transformed host cell. A vector may include nucleic acid sequences that permit it to replicate in a host cell, such as an origin of replication. A vector may also include one or more selectable marker genes and other genetic elements known in the art. In some aspects, the vector is a viral vector, such as a lentivirus vector. 4239-112594-02 Wild-type protein or sequence: A polypeptide, nucleic acid molecule, or sequence thereof that has not been modified, for example, by selective mutation. Wild-type proteins or sequences are also referred to as “native” protein or sequence. IV. Recombinant IL-2 proteins Novel recombinant interleukin-2 (IL-2) proteins are provided herein. In particular, provided are recombinant IL-2 proteins that are selectively mutated to be partial agonists of IL-2R-based signaling, or to increase IL-2R-based signaling, as compared to wild-type IL-2. The recombinant IL-2 proteins are useful, for example, in applications where fine-tuning one or more IL-2 functions is useful (e.g., in the treatment of autoimmune disease and cancer). Unless context indicates otherwise, the amino acid numbering for mutations in recombinant IL-2 proteins provided herein is according to the reference IL-2 protein sequence set forth as SEQ ID NO: 6. In some aspects, the recombinant IL-2 protein includes Q22E and Q126T substitutions. In some examples, the recombinant IL-2 protein further includes L80F, R81D, L85V, I86V, and / or I92F amino acid substitutions. In some aspects, the recombinant IL-2 protein includes the Q22E and Q126T amino acid substitutions and an amino acid sequence at least 80% (such as at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NO: 8. In some aspects, the recombinant IL- 2 protein includes the Q22E, Q126T, L80F, R81D, L85V, I86V, and I92F amino acid substitutions, and an amino acid sequence at least 80% (such as at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NO: 24. In some aspects, the recombinant IL-2 protein includes or consists of an amino acid sequence set forth as SEQ ID NO: 20 or SEQ ID NO: 36. In some such aspects, the recombinant IL-2 protein has a reduced capability to stimulate STAT5 phosphorylation in T cells as compared to wild-type human IL-2. In some such aspects, the recombinant IL-2 protein induces proliferation of fewer CD8+T cells and more Treg cells as compared to wild- type human IL-2 when incubated with PBMCs. In some such aspects, the recombinant IL-2 protein induces lower proliferation of CD8+T cells and greater proliferation of Treg cells as compared to wild-type human IL-2 when incubated with PBMCs. In some aspects, the recombinant IL-2 protein includes L18R, Q22E, and S130R substitutions. In some examples, the recombinant IL-2 protein further includes L80F, R81D, L85V, I86V, and I92F amino acid substitutions. In some aspects, the recombinant IL-2 protein includes the L18R, Q22E, and S130R amino acid substitutions and an amino acid 4239-112594-02 sequence at least 80% (such as at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NO: 20. In some aspects, the recombinant IL-2 protein includes the L18R, Q22E, S130R, L80F, R81D, L85V, I86V, and I92F amino acid substitutions, and an amino acid sequence at least 80% (such as at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NO: 36. In some aspects, the recombinant IL-2 protein includes or consists of an amino acid sequence set forth as SEQ ID NO: 20 or SEQ ID NO: 36. In some such aspects, the recombinant IL-2 protein has an increased capability to stimulate STAT5 phosphorylation in T cells as compared to wild-type human IL-2. In some aspects, the recombinant IL-2 protein includes L18R and Q126T substitutions. In some examples, the recombinant IL-2 protein further includes L80F, R81D, L85V, I86V, and I92F amino acid substitutions. In some aspects, the recombinant IL-2 protein includes the L18R and Q126T amino acid substitutions and an amino acid sequence at least 80% (such as at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NO: 10. In some aspects, the recombinant IL-2 protein includes the L18R, Q126T, L80F, R81D, L85V, I86V, and I92F amino acid substitutions, and an amino acid sequence at least 80% (such as at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NO: 26. In some aspects, the recombinant IL-2 protein includes or consists of an amino acid sequence set forth as SEQ ID NO: 10 or SEQ ID NO: 26. In some such aspects, the recombinant IL-2 protein has a reduced capability to stimulate STAT5 phosphorylation in T cells as compared to wild-type human IL-2. In some such aspects, the recombinant IL-2 protein induces proliferation of fewer CD8+T cells and more Treg cells as compared to wild- type human IL-2 when incubated with PBMCs. In some such aspects, the recombinant IL-2 protein induces lower proliferation of CD8+T cells and greater proliferation of Treg cells as compared to wild-type human IL-2 when incubated with PBMCs. In some aspects, the recombinant IL-2 protein includes Q126T and S130R substitutions. In some examples, the recombinant IL-2 protein further includes L80F, R81D, L85V, I86V, and I92F amino acid substitutions. In some aspects, the recombinant IL-2 protein includes the Q126T and S130R amino acid substitutions and an amino acid sequence at least 80% (such as at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NO: 12. In some aspects, the recombinant IL-2 protein includes the Q126T, S130R, L80F, R81D, L85V, I86V, and I92F amino acid substitutions, and an amino acid sequence at least 80% (such as at least 85%, at least 90%, at 4239-112594-02 least 95%, at least 96%, at least 97%, at least 98%, or at least 99%) identical to SEQ ID NO: 28. In some aspects, the recombinant IL-2 protein includes or consists of an amino acid sequence set forth as SEQ ID NO: 12 or SEQ ID NO: 28. In some such aspects, the recombinant IL-2 protein has a reduced capability to stimulate STAT5 phosphorylation in T cells as compared to wild-type human IL-2. In some such aspects, the recombinant IL-2 protein induces proliferation of fewer CD8+T cells and more Treg cells as compared to wild- type human IL-2 when incubated with PBMCs. In some such aspects, the recombinant IL-2 protein induces lower proliferation of CD8+T cells and greater proliferation of Treg cells as compared to wild-type human IL-2 when incubated with PBMCs. The provided recombinant IL-2 protein can be a mutated form of any mammalian IL- 2, such as human or mouse IL-2. Any cell that is competent for IL-2 signaling can be treated with the recombinant IL-2 protein as described herein. In some aspects, the cells are T cells (such as CD8+T cells, CD4+T cell, Tregs), NK cells, ILC2 cells, activated monocytes, or B cells. In some aspects, the recombinant IL-2 proteins that are partial agonists have one or more reduced functions as compared to wild-type IL-2. In certain aspects, the recombinant IL-2 protein has reduced capabilities to stimulate one or more signaling pathways that are dependent on IL-2Rβ / IL-2Rγc heterodimerization. In some aspects, the recombinant IL-2 protein has a reduced capability to stimulate STAT5 phosphorylation in an IL-2Rβ+cell as compared to wild-type IL-2. In some aspects, the recombinant IL-2 protein stimulates STAT5 phosphorylation in an IL-2Rβ+cell at a level that is 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or less of the level that wild-type IL-2 stimulates STAT5 phosphorylation in the same cell. In some aspects, the cells are T cells (such as CD8+T cells, CD4+T cell, Tregs), NK cells, ILC2 cells, activated monocytes, or B cells. In particular aspects, the T cell is a CD8+T cell. In some aspects, the T cell is a CAR T cell. In some aspects, the CD8+T cell is a freshly isolated CD8+T cell. In other aspects, the CD8+T cell T cell is an activated CD8+ T cell. In other aspects, the IL-2Rβ+cell is a NK cell. In some aspects, the recombinant IL-2 protein has a reduced capability to stimulate ERK1 / ERK2 signaling in an IL-2Rβ+cell as compared to wild-type IL-2. In some aspects, the recombinant IL-2 protein stimulates pERKl / ERK2 signaling in an IL-2Rβ+cell at a level that is 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or less of the level that wild-type IL-2 stimulates pERKl / ERK2 4239-112594-02 signaling in the same cell. In some aspects, the cells are T cells (such as CD8+T cells, CD4+T cell, Tregs), NK cells, ILC2 cells, activated monocytes, or B cells. In particular aspects, the T cell is a CD8+T cell. In some aspects, the T cell is a CAR T cell. In some aspects, the CD8+T cell is a freshly isolated CD8+T cell. In other aspects, the CD8+T cell T cell is an activated CD8+ T cell. In other aspects, the IL-2Rβ+cell is a NK cell. STAT5 and ERK1 / 2 signaling can be measured, for example, by phosphorylation of STAT5 and ERK1 / 2 using any suitable method known in the art. For example, STAT5 and ERK1 / 2 phosphorylation can be measured using antibodies specific for the phosphorylated version of these molecules in combination with flow cytometry analysis. In some aspects, the recombinant IL-2 protein has a reduced capability to stimulate PI3-kinase signaling in an IL-2Rβ+cell as compared to wild-type IL-2. In some aspects, the recombinant IL-2 protein stimulates PI3-kinase signaling in an IL-2Rβ+cell at a level that is 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or less of the level that wild-type IL-2 stimulates PI3-kinase signaling in the same cell. In some aspects, the cells are T cells (such as CD8+T cells, CD4+T cell, Tregs), NK cells, ILC2 cells, activated monocytes, or B cells. In particular aspects, the T cell is a CD8+T cell. In some aspects, the T cell is a CAR T cell. In some aspects, the CD8+T cell is a freshly isolated CD8+T cell. In other aspects, the CD8+T cell T cell is an activated CD8+ T cell. In other aspects, the IL-2Rβ+cell is a NK cell. PI3-kinase signaling can be measured using any suitable method known in the art. For example, PI3-kinase signaling can be measured using antibodies that are specific for phospho-S6 ribosomal protein in conjunction with flow cytometry analysis. In certain aspects, the recombinant IL-2 protein has a reduced capability to induce lymphocyte proliferation as compared to wild-type IL-2. In some aspects, the lymphocyte is a T cell. In particular aspects, the lymphocyte is a primary CD8+T cell. In other aspects, the lymphocyte is an activated CD8+T cell. Cell proliferation can be measured using any suitable method known in the art. For example, lymphocyte proliferation can be measured using a carboxyfluorescein diacetate succinimidyl diester (CFSE) dilution assay or by [3H]- thymidine incorporation, according to known methods. In some aspects, the IL-2 mutein induces lymphocyte proliferation at a level that is 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or less of the level that wild-type IL-2 induce lymphocyte proliferation. In some aspects, the recombinant IL-2 protein has a reduced capability to activate IL- 2Rα expression in a lymphocyte as compared to wild-type IL-2. In some aspects, the IL-2 4239-112594-02 mutein activates IL-2Rα expression in a lymphocyte at a level that is 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or less of the level that wild-type IL-2 activates IL-2Rα expression in the same cell. In some aspects, the lymphocyte is a CD8+T cell. In some aspects, the CD8+T cell is a freshly isolated CD8+ T cell. In other aspects, the CD8+T cell is an activated CD8+T cell. In certain aspects the recombinant IL-2 protein is an inhibitor of IL-2 and / or IL-15 STAT5 phosphorylation in CD8+T cells. In some aspects, the mutein is an inhibitor of IL-2 and / or IL-15 induced proliferation of CD8+T cells. In some aspects, the mutein is an inhibitor of IL-2 dependent, TCR-induced cell proliferation. Several aspects include a multimer of the recombinant IL-2 protein, for example, a multimer including 2, 3, 4, 5, 6, 7, 8, 9, or 10, or more of the recombinant IL-2 protein. It is understood that some variations can be made in the amino acid sequence of a protein without affecting the activity of the protein. Such variations include insertion of amino acid residues, deletions of amino acid residues, and substitutions (such as conservative substitutions) of amino acid residues. These variations in sequence can be naturally occurring variations or they can be engineered through the use of genetic engineering techniques. Examples of such techniques are found in see, e.g., Sambrook et al. (Molecular Cloning: A Laboratory Manual, 4thed, Cold Spring Harbor, New York, 2012) and Ausubel et al. (In Current Protocols in Molecular Biology, John Wiley & Sons, New York, through supplement 104, 2013). In the purified form, the disclosed recombinant IL-2 protein typically does not include a signal peptide, as the signal peptide is proteolytically cleaved during cellular processing. The recombinant IL-2 protein can be derivatized or linked to another molecule (such as another peptide or protein). In general, the recombinant IL-2 protein is derivatized such that the binding to IL-2R is not affected adversely by the derivatization or labeling. For example, the recombinant IL-2 protein can be functionally linked (by chemical coupling, genetic fusion, noncovalent association or otherwise) to one or more other molecular entities, such as an antibody, protein or detection tag. In some aspects, the disclosed recombinant IL-2 protein is fused or linked to a heterologous protein, for example to generate a fusion or chimeric polypeptide that includes a subject IL-2 mutein and the heterologous protein (i.e., a polypeptide that is not IL-2 or a mutant thereof). Exemplary heterologous polypeptides can increase the circulating half-life of the chimeric polypeptide in vivo, and may, therefore, further enhance the properties of the recombinant IL-2 protein. In various aspects, the protein that increases the circulating half- 4239-112594-02 life may be a serum albumin, such as human or mouse serum albumin, or the Fc region of the IgG subclass of antibodies that lacks the IgG heavy chain variable region. Exemplary Fc regions can include a mutation that inhibits complement fixation and Fc receptor binding, or it may be lytic, able to bind complement or to lyse cells via another mechanism, such as antibody-dependent complement lysis (ADCC). The “Fc region” can be a naturally occurring or synthetic polypeptide that is homologous to the IgG C-terminal domain produced by digestion of IgG with papain. IgG Fc has a molecular weight of approximately 50 kDa. The mutant IL-2 polypeptides can include the entire Fc region, or a smaller portion that retains the ability to extend the circulating half- life of a chimeric polypeptide of which it is a part. In addition, full-length or fragmented Fc regions can be variants of the wild-type molecule. That is, they can contain mutations that may or may not affect the function of the polypeptides; native activity is not necessary or desired in all cases. In certain aspects, the recombinant IL-2 protein is fused or linked to an IgG1 , IgG2, IgG3, or IgG4 Fc region. In other aspects, the recombinant IL-2 protein is linked or fused to an antibody or antigen-binding portion thereof. The antibody or antigen-binding component of the chimeric molecule can serve as a targeting moiety. For example, it can be used to localize the chimeric molecule to a particular subset of cells or target molecule. V. Polynucleotides and Expression Polynucleotides encoding a disclosed recombinant IL-2 protein are also provided. These polynucleotides include DNA, cDNA and RNA sequences which encode the antigen. One of skill in the art can readily use the genetic code to construct a variety of functionally equivalent nucleic acids, such as nucleic acids which differ in sequence but which encode the same protein sequence, or encode a conjugate or fusion protein including the nucleic acid sequence. The DNA sequence of human (or other species) IL-2 can be modified to introduce the amino acid substitutions and deletions disclosed herein. Exemplary nucleic acids can be prepared by cloning techniques. Examples of appropriate cloning and sequencing techniques, and instructions sufficient to direct persons of skill through many cloning exercises are known (see, e.g., Sambrook et al. (Molecular Cloning: A Laboratory Manual, 4thed, Cold Spring Harbor, New York, 2012) and Ausubel et al. (In Current Protocols in Molecular Biology, John Wiley & Sons, New York, through supplement 104, 2013). 4239-112594-02 Nucleic acids can also be prepared by amplification methods. Amplification methods include polymerase chain reaction (PCR), the ligase chain reaction (LCR), the transcription- based amplification system (TAS), the self-sustained sequence replication system (3SR). A wide variety of cloning methods, host cells, and in vitro amplification methodologies are well known to persons of skill. The polynucleotides encoding a disclosed recombinant IL-2 protein can include a recombinant DNA which is incorporated into a vector (such as an expression vector) into an autonomously replicating plasmid or virus or into the genomic DNA of a prokaryote or eukaryote, or which exists as a separate molecule (such as a cDNA) independent of other sequences. The nucleotides can be ribonucleotides, deoxyribonucleotides, or modified forms of either nucleotide. The term includes single and double forms of DNA. Polynucleotide sequences encoding a disclosed recombinant IL-2 protein can be operatively linked to expression control sequences. An expression control sequence operatively linked to a coding sequence is ligated such that expression of the coding sequence is achieved under conditions compatible with the expression control sequences. The expression control sequences include, but are not limited to, appropriate promoters, enhancers, transcription terminators, a start codon (i.e., ATG) in front of a protein-encoding gene, splicing signal for introns, maintenance of the correct reading frame of that gene to permit proper translation of mRNA, and stop codons. DNA sequences encoding the disclosed recombinant IL-2 protein can be expressed in vitro by DNA transfer into a suitable host cell. The cell may be prokaryotic or eukaryotic. The term also includes any progeny of the subject host cell. It is understood that all progeny may not be identical to the parental cell since there may be mutations that occur during replication. Methods of stable transfer, meaning that the foreign DNA is continuously maintained in the host, are known in the art. Hosts can include microbial, yeast, insect and mammalian organisms. Methods of expressing DNA sequences having eukaryotic or viral sequences in prokaryotes are well known in the art. Non-limiting examples of suitable host cells include bacteria, archea, insect, fungi (for example, yeast), plant, and animal cells (for example, mammalian cells, such as human). Exemplary cells of use include Escherichia coli, Bacillus subtilis, Saccharomyces cerevisiae, Salmonella typhimurium, SF9 cells, C129 cells, 293 cells, Neurospora, and immortalized mammalian myeloid and lymphoid cell lines. Techniques for the propagation of mammalian cells in culture are well-known (see, e.g., Helgason and Miller (Eds.), 2012, Basic Cell Culture Protocols (Methods in Molecular Biology), 4thEd., Humana 4239-112594-02 Press). Examples of commonly used mammalian host cell lines are VERO and HeLa cells, CHO cells, and WI38, BHK, and COS cell lines, although other cell lines may be used, such as cells designed to provide higher expression, desirable glycosylation patterns, or other features. In some aspects, the host cells include HEK293 cells or derivatives thereof. Transformation of a host cell with recombinant DNA can be carried out by conventional techniques. Where the host is prokaryotic, such as, but not limited to, E. coli, competent cells which are capable of DNA uptake can be prepared from cells harvested after exponential growth phase and subsequently treated by the CaCl2method using standard procedures. Alternatively, MgCl2 or RbCl can be used. Transformation can also be performed after forming a protoplast of the host cell if desired, or by electroporation. When the host is a eukaryote, such methods of transfection of DNA as calcium phosphate coprecipitates, conventional mechanical procedures such as microinjection, electroporation, insertion of a plasmid encased in liposomes, or viral vectors can be used. Eukaryotic cells can also be co-transformed with polynucleotide sequences encoding a disclosed antigen, and a second foreign DNA molecule encoding a selectable phenotype, such as the herpes simplex thymidine kinase gene. Another method is to use a eukaryotic viral vector, such as simian virus 40 (SV40) or bovine papilloma virus, to transiently infect or transform eukaryotic cells and express the protein (see for example, Viral Expression Vectors, Springer press, Muzyczka ed., 2011). Appropriate expression systems such as plasmids and vectors of use in producing proteins in cells including higher eukaryotic cells such as the COS, CHO, HeLa and myeloma cell lines. Modifications can be made to a nucleic acid encoding a disclosed recombinant IL-2 protein without diminishing its biological activity. Some modifications can be made to facilitate the cloning, expression, or incorporation of the target molecule into a fusion protein. Such modifications are well known to those of skill in the art and include, for example, termination codons, a methionine added at the amino terminus to provide an initiation, site, additional amino acids placed on either terminus to create conveniently located restriction sites, or additional amino acids (such as poly His) to aid in purification steps. A nucleic acid molecule encoding a disclosed recombinant IL-2 protein can be included in a viral vector, for example, for expression of the disclosed recombinant IL-2 protein in a host cell, or for administration to a subject as disclosed herein. In some examples, the viral vector can be replication-competent. For example, the viral vector can have a mutation (e.g., insertion of nucleic acid encoding the recombinant IL- 4239-112594-02 2 protein) in the viral genome that attenuates, but does not completely block viral replication in host cells. VI. Pharmaceutical Compositions Pharmaceutical compositions comprising a disclosed recombinant IL-2 protein or nucleic acid molecule or vector encoding the recombinant IL-2 protein and a pharmaceutically acceptable carrier are also provided. Such pharmaceutical compositions can be administered to subjects by a variety of administration modes known to the person of ordinary skill in the art, for example, intramuscular, intradermal, subcutaneous, intravenous, intra-arterial, intra-articular, intraperitoneal, intranasal, sublingual, tonsillar, oropharyngeal, or other parenteral and mucosal routes. Methods for preparing administrable compositions are described in more detail in such publications as Remington: The Science and Practice of Pharmacy, 22nded., London, UK: Pharmaceutical Press, 2013. Thus, a recombinant IL-2 protein or nucleic acid molecule or vector encoding the recombinant IL-2 protein described herein can be formulated with pharmaceutically acceptable carriers to help retain biological activity while also promoting increased stability during storage within an acceptable temperature range. Potential carriers include, but are not limited to, physiologically balanced culture medium, phosphate buffer saline solution, water, emulsions (e.g., oil / water or water / oil emulsions), various types of wetting agents, cryoprotective additives or stabilizers such as proteins, peptides or hydrolysates (e.g., albumin, gelatin), sugars (e.g., sucrose, lactose, sorbitol), amino acids (e.g., sodium glutamate), or other protective agents. The resulting aqueous solutions may be packaged for use as is or lyophilized. Lyophilized preparations are combined with a sterile solution prior to administration for either single or multiple dosing. Formulated compositions, especially liquid formulations, may contain a bacteriostat to prevent or minimize degradation during storage, including but not limited to effective concentrations (usually ≦1% w / v) of benzyl alcohol, phenol, m-cresol, chlorobutanol, methylparaben, and / or propylparaben. A bacteriostat may be contraindicated for some patients; therefore, a lyophilized formulation may be reconstituted in a solution either containing or not containing such a component. The pharmaceutical compositions of the disclosure can contain as pharmaceutically acceptable vehicles substances as required to approximate physiological conditions, such as pH adjusting and buffering agents, tonicity adjusting agents, wetting agents and the like, for 4239-112594-02 example, sodium acetate, sodium lactate, sodium chloride, potassium chloride, calcium chloride, sorbitan monolaurate, and triethanolamine oleate. In some aspects, the composition can be provided as a sterile composition. The pharmaceutical composition typically contains an effective amount of a disclosed recombinant IL-2 protein or nucleic acid molecule or vector encoding the recombinant IL-2 protein and can be prepared by conventional techniques. Typically, the amount of recombinant IL-2 protein or nucleic acid molecule or vector encoding the recombinant IL-2 protein in each dose of the pharmaceutical composition is selected as an amount which provides a therapeutic benefit (either alone or in combination with prior or future doses) without significant, adverse side effects. In some aspects, the composition can be provided in unit dosage form for use in a subject, for example, for the treatment of cancer or an autoimmune disease in the subject. A unit dosage form contains a suitable single preselected dosage for administration to a subject, or suitable marked or measured multiples of two or more preselected unit dosages, and / or a metering mechanism for administering the unit dose or multiples thereof. In some aspects, the pharmaceutical composition comprises mRNA encoding the recombinant IL-2 protein formulated in a lipid nanoparticle. The lipid nanoparticles typically comprise ionizable cationic lipid, non-cationic lipid, sterol and PEG lipid components along with the nucleic acid cargo of interest. The lipid nanoparticles of the disclosure can be generated using any suitable components, compositions, and methods, such as described in PCT / US2016 / 052352; PCT / US2016 / 068300; PCT / US2017 / 037551; PCT / US2015 / 027400; PCT / US2016 / 047406; PCT / US2016000129; PCT / US2016 / 014280; PCT / US2016 / 014280; PCT / US2017 / 038426; PCT / US2014 / 027077; PCT / US2014 / 055394; PCT / US2016 / 52117; PCT / US2012 / 069610; PCT / US2017 / 027492; PCT / US2016 / 059575, PCT / US2016 / 069491, and U.S. App. Publ.2022 / 0241399. In several aspects, the mRNA is formulated in a lipid nanoparticle; for example, comprising a PEG-modified lipid, a non-cationic lipid, a sterol, an ionizable lipid, or any combination thereof. In some aspects, the lipid nanoparticle is composed of 50 mol% ionizable lipid ((2 hydroxyethyl)(6 oxo 6-(undecycloxy)hexyl)amino)octanoate, 10 mol% 1,2 distearoyl sn glycerol-3 phosphocholine (DSPC), 38.5 mol% cholesterol, and 1.5 mol% 1- monomethoxypolyethyleneglycol-2,3,dimyristylglycerol with polyethylene glycol of average molecular weight 2000 (PEG2000 DMG). The mRNA / lipid nanoparticle composition may be provided in any suitable carrier, such as a sterile liquid for injection at a concentration of 4239-112594-02 0.5 mg / mL in 20 mM trometamol (Tris) buffer containing 87 mg / mL sucrose and 10.7 mM sodium acetate, at pH 7.5 and with appropriate diluent. VII. Methods of Treating an Autoimmune Disease or Disorder Methods are provided herein for the treatment of subjects that have an autoimmune disease or disorder, such as colitis or systemic lupus erythematosus, by administering to a subject with or at risk of such a disorder a therapeutically effective amount of a pharmaceutical composition comprising a disclosed recombinant IL-2 protein or nucleic acid molecule or vector encoding the recombinant IL-2 protein. Although the treatment of colitis and systemic lupus erythematosus is exemplified herein, any type of autoimmune disorder can be treated using the disclosed compositions and methods, e.g. rheumatoid arthritis, type 1 diabetes, multiple sclerosis, Sjögren’s syndrome, Graves’ disease, myasthenia gravis, ulcerative colitis, Hashimoto’s thyroiditis, celiac disease, Crohn’s disease, arthritis, inflammatory bowel disease, psoriasis, or scleroderma. In some examples, the method reduces one or more symptoms of an autoimmune disease by at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or even 100%. Administration of the pharmaceutical composition can be local or systemic. Exemplary routes of administration include, but are not limited to, oral, injection (such as subcutaneous, intramuscular, intradermal, intraperitoneal, intravenous, intracranial, intracerebral, intrathecal, intraspinal), sublingual, rectal, transdermal (for example, topical), intranasal, vaginal, and inhalation routes. In some examples, the pharmaceutical composition is injected or infused into an afflicted area (local administration). Appropriate routes of administration can be determined by a skilled clinician based on factors such as the subject, the condition being treated, and other factors. A therapeutically effective amount of a recombinant IL-2 protein for treatment of an autoimmune disorder depends on several factors, including the polypeptide selected. For instance, single dose amounts in the range of approximately 0.001 to 0.1 mg / kg of patient body weight can be administered; in some aspects, about 0.005, 0.01, 0.05 mg / kg may be administered. The compositions can be administered, for example, from one or more times per day to one or more times per week, including once every other day. The skilled artisan will appreciate that certain factors may influence the dosage and timing required to effectively treat a subject, including but not limited to the severity of the disease or disorder, previous treatments, the general health and / or age of the subject, and other diseases present. 4239-112594-02 Moreover, treatment of a subject with a therapeutically effective amount of the subject IL-2 muteins can include a single treatment or can include a series of treatments. In some examples, the effective amount of pharmaceutical composition comprising the recombinant IL-2 protein or nucleic acid molecule encoding the recombinant IL-2 protein, is an amount sufficient to prevent, treat, reduce, and / or ameliorate one or more signs or symptoms of the autoimmune disease or disorder in the subject. In a specific, non-limiting example, the effective amount is an amount sufficient to reduce inflammation in the subject. For example, reducing inflammation in the subject by at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 100%, or more as compared to a suitable control (e.g., an untreated subject or a baseline reading of the same subject prior to treatment). In another example, the effective amount is an amount sufficient to reduce blood glucose levels (such as in a diabetic subject) to a normal level or range. In some examples, the subject receives an additional treatment, such as one or more of an anti-inflammatory, humanized monoclonal antibody (e.g., ocrelizumab), beta interferon (e.g., Avonex (interferon beta 1a), Rebif (interferon beta 1a), Plegridy (peginterferon beta 1a), Betaferon (interferon beta 1b), Extavia (interferon beta 1b)), IL-17 or IL-17R inhibitors (e.g. Secukinumab, Ixekizumab, Brodalumab) or cell migration inhibitors (e.g., Natalizumab, Fingolimod). In specific non-limiting examples, the additional treatment is a corticosteroid (e.g., prednisone or methylprednisolone), Glatiramer acetate, Fingolimod, Dimethyl fumarate, Diroximel fumarate, Teriflunomide, Siponimod, Cladribine, Ocrelizumab, Natalizumab, and / or Alemtuzumab. Such additional treatments can be administered before, after, or concurrently with the recombinant IL-2 protein or nucleic acid molecule encoding the recombinant IL-2 protein. VIII. Methods of Treating Cancer or Enhancing Cancer Immunotherapy Disclosed herein are methods of treating a subject with cancer which include administering a therapeutically effective amount of a pharmaceutical composition comprising a recombinant IL-2 protein as described herein, or a nucleic acid molecule or vector encoding the recombinant IL-2 protein. In other aspects, the method includes culturing T cells or NK cells with an effective amount of a recombinant IL-2 protein or composition thereof (or a nucleic acid molecule or vector encoding the recombinant IL-2 protein), thereby expanding the T cells or NK cells, and adoptively transferring the expanded T cells or NK cells to the 4239-112594-02 subject to treat the cancer. In some examples, the T cells are CD8+ T cells and / or CAR T cells. Both hematological and solid cancers can be treated. Thus, in some aspects, the hematological (or hematogenous) cancer treated with the methods provided herein is a leukemia, such as lymphoma, Hodgkin's disease, non-Hodgkin's lymphoma (indolent or high grade forms), multiple myeloma, Waldenstrom's macroglobulinemia, heavy chain disease, myelodysplastic syndrome, hairy cell leukemia or myelodysplasia. In some cases, lymphomas are considered solid tumors. In some aspects, the cancer treated with the methods provided herein is a solid tumor. Solid tumors can be benign or malignant. Examples of solid tumors, such as sarcomas and carcinomas, that can be treated with the methods provided herein include fibrosarcoma, myxosarcoma, liposarcoma, chondrosarcoma, osteosarcoma, and other sarcomas, synovioma, mesothelioma, Ewing's tumor, leiomyosarcoma, rhabdomyosarcoma, colon carcinoma, lymphoid malignancy, pancreatic cancer, breast cancer, lung cancers, ovarian cancer, prostate cancer, hepatocellular carcinoma, squamous cell carcinoma, basal cell carcinoma, adenocarcinoma, sweat gland carcinoma, medullary thyroid carcinoma, papillary thyroid carcinoma, pheochromocytoma, sebaceous gland carcinoma, papillary carcinoma, papillary adenocarcinoma, medullary carcinoma, bronchogenic carcinoma, renal cell carcinoma, hepatoma, bile duct carcinoma, choriocarcinoma, Wilms' tumor, cervical cancer, testicular tumor, seminoma, bladder carcinoma, melanoma, and CNS tumors (such as a glioma (such as brainstem glioma and mixed gliomas), glioblastoma (also known as glioblastoma multiforme) astrocytoma, CNS lymphoma, germinoma, medulloblastoma, Schwannoma craniopharyogioma, ependymoma, pinealoma, hemangioblastoma, acoustic neuroma, oligodendroglioma, menangioma, head and neck cancers, neuroblastoma, retinoblastoma and brain metastasis. Administration of the pharmaceutical composition (as well as compositions that include the expanded T cells or NK cells for adoptive cell transfer) can be local or systemic. Exemplary routes of administration include, but are not limited to, oral, injection (such as subcutaneous, intramuscular, intradermal, intraperitoneal, intravenous, intracranial, intracerebral, intrathecal, intraspinal), sublingual, rectal, transdermal (for example, topical), intranasal, vaginal, and inhalation routes. In some examples, the pharmaceutical composition is injected or infused into a tumor, or close to a tumor (local administration), or administered to the peritoneal cavity. Appropriate routes of administration can be determined by a skilled clinician based on factors such as the subject, the condition being treated, and other factors. 4239-112594-02 A therapeutically effective amount of a recombinant IL-2 protein depends on several factors, including the polypeptide selected and the subject to be treated. For instance, single dose amounts in the range of approximately 0.001 to 0.1 mg / kg of patient body weight can be administered; in some aspects, about 0.005, 0.01, 0.05 mg / kg may be administered. In some aspects, 600,000 IU / kg is administered (IU can be determined by a lymphocyte proliferation bioassay and is expressed in International Units (IU) as established by the World Health Organization 1stInternational Standard for Interleukin-2 (human)). The dosage may be similar to, but is expected to be less than, that prescribed for PROLEUKIN®. The compositions can be administered one from one or more times per day to one or more times per week; including once every other day. The skilled artisan will appreciate that certain factors may influence the dosage and timing required to effectively treat a subject, including but not limited to the severity of the disease or disorder, previous treatments, the general health and / or age of the subject, and other diseases present. Moreover, treatment of a subject with a therapeutically effective amount of the subject IL-2 muteins can include a single treatment or can include a series of treatments. In one aspect, the compositions are administered every 8 hours for five days, followed by a rest period of 2 to 14 days, e.g., 9 days, followed by an additional five days of administration every 8 hours. A therapeutically effective amount of a composition that includes T cells or NK cells for adoptive transfer can also vary depending on several factors, including age, weight, tumor type, tumor size, extent of metastasis, and condition of the patient (subject). In some examples, the composition includes about 104to 1012of the expanded T cells or NK cells (for example, about 104-107cells, about 106-109cells, or about 108-1012cells). For example, the composition may be administered at a dose of about 104to 109cells / kg body weight, such as 105to 106cells / kg body weight, including all integer values within those ranges. Exemplary doses are 106cells / kg to about 108cells / kg, such as from about 5 x 106cells / kg to about 7.5 x 107cells / kg, such as at about 2.5 x 107cells / kg, or at about 5.0 x 107cells / kg. The T cell and NK cell compositions can be administered once or multiple times, such as 2, 3, 4, 5, 6, 7, 8, 9 or 10 times at these dosages. The compositions can be administered daily, weekly, bimonthly or monthly. In some non-limiting examples, the composition is formulated for intravenous administration and is administered multiple times. The quantity and frequency of administration will be determined by such factors as the condition of the subject, and the type and severity of the subject’s disease, although appropriate dosages may be determined by clinical trials. 4239-112594-02 In some examples, the therapeutically effective amount of the pharmaceutical composition (including compositions that contain adoptively transferred cells), is an amount sufficient to prevent, treat, reduce, and / or ameliorate one or more signs or symptoms of cancer in the subject. For example, an amount sufficient to reduce tumor size or tumor load in the subject by at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 100%, or more, as compared to a baseline measurement for the same subject, or a suitable control. In some examples, the effective amount is an amount sufficient to inhibit or slow metastasis in the subject. For example, by decreasing tumor spread in the subject by at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 100%, or more, as compared to a suitable control (e.g., an untreated subject or a baseline reading of the same subject prior to treatment). In some examples, the effective amount is an amount that increases life expectancy of the subject, for example, by at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 100%, at least 200%, or more. The control subjects can be untreated subject, subjects not receiving the recombinant IL-2 protein (e.g., subjects receiving other agents or alternative therapies). In some examples, the therapeutically effective amount of the composition is an amount that enhances an additional therapy, such as an additional immunotherapy (e.g., a monoclonal antibody, chimeric antigen receptor (CAR)-expressing T cells, an immunotoxin, or an anti-tumor vaccine). For example, an amount sufficient that when administered with an additional immunotherapy, reduces tumor size or tumor load in the subject by at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 100%, or more, as compared to a suitable control (e.g., a subject not receiving the combination treatment). In some examples, the effective amount to enhance immunotherapy is an amount sufficient to inhibit or slow metastasis in the subject. For example, by decreasing tumor spread in the subject by at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 100%, or more, as compared to a suitable control. In some examples, the effective amount to enhance immunotherapy is an amount that increases life expectancy of the subject, for example, by at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 100%, at least 200%, or more. The control subjects can be untreated subject, or subjects not receiving the recombinant IL-2 protein, or subjects not receiving a combination treatment including recombinant IL-2 protein. 4239-112594-02 In some examples, the subject receives an additional treatment, such as one or more of surgery, radiation, chemotherapy, immunotherapy, or other therapeutic. Exemplary chemotherapeutic agents include (but are not limited to) alkylating agents, such as nitrogen mustards (such as mechlorethamine, cyclophosphamide, melphalan, uracil mustard or chlorambucil), alkyl sulfonates (such as busulfan), nitrosoureas (such as carmustine, lomustine, semustine, streptozocin, or dacarbazine); antimetabolites such as folic acid analogs (such as methotrexate), pyrimidine analogs (such as 5-FU or cytarabine), and purine analogs, such as mercaptopurine or thioguanine; or natural products, for example vinca alkaloids (such as vinblastine, vincristine, or vindesine), epipodophyllotoxins (such as etoposide or teniposide), antibiotics (such as dactinomycin, daunorubicin, doxorubicin, bleomycin, plicamycin, or mitocycin C), and enzymes (such as L-asparaginase). Additional agents include platinum coordination complexes (such as cis-diamine-dichloroplatinum II, also known as cisplatin), substituted ureas (such as hydroxyurea), methyl hydrazine derivatives (such as procarbazine), and adrenocrotical suppressants (such as mitotane and aminoglutethimide); hormones and antagonists, such as adrenocorticosteroids (such as prednisone), progestins (such as hydroxyprogesterone caproate, medroxyprogesterone acetate, and magestrol acetate), estrogens (such as diethylstilbestrol and ethinyl estradiol), antiestrogens (such as tamoxifen), and androgens (such as testosterone proprionate and fluoxymesterone). Examples of the most commonly used chemotherapy drugs include adriamycin, melphalan (Alkeran®) Ara-C (cytarabine), carmustine, busulfan, lomustine, carboplatinum, cisplatinum, cyclophosphamide (Cytoxan®), daunorubicin, dacarbazine, 5- fluorouracil, fludarabine, hydroxyurea, idarubicin, ifosfamide, methotrexate, mithramycin, mitomycin, mitoxantrone, nitrogen mustard, paclitaxel (or other taxanes, such as docetaxel), vinblastine, vincristine, VP-16, while newer drugs include gemcitabine (Gemzar®), trastuzumab (Herceptin®), irinotecan (CPT-11), leustatin, navelbine, rituximab (Rituxan®) imatinib (STI-571), Topotecan (Hycamtin®), capecitabine, ibritumomab (Zevalin®), and calcitriol. A skilled clinician can select appropriate additional therapies (from those listed here or other current therapies) for the subject, depending on factors such as the subject, the cancer being treated, treatment history, and other factors. In some examples, the additional therapeutic is a cell cycle or checkpoint inhibitor. In some examples, the checkpoint inhibitor targets PD-1, PD-L1, CTLA-4, CDK4, and / or CDK6. Exemplary inhibitors include ipilimumab, nivolumab, pembrolizumab, atezolizumab, avelumab, durvalumab, cemiplimab, palbociclib, ribociclib, and abemaciclib. 4239-112594-02 In some examples, the additional treatment is immunotherapy and comprises administering to the subject a monoclonal antibody, a chimeric antigen receptor (CAR)- expressing T cell, an immunotoxin, or an anti-tumor vaccine. In some examples, the subject is administered an effective amount of the agent and an additional immunotherapy, and the effective amount of the agent is an amount that enhances the additional immunotherapy (e.g., synergistic). Such additional treatments can be administered before, after, or concurrently with the pharmaceutical composition comprising the recombinant IL-2 protein, or nucleic acid molecule or vector encoding the recombinant IL-2 protein, or T cells or NK cells for adoptive cell transfer. Adoptive transfer of antigen-specific T cells represents a major advance in cancer immunotherapy, with robust clinical outcomes in some patients. Both the number of transferred T cells and their differentiation state are important determinants of effective responses. T cells can be expanded with T cell receptor (TCR)-mediated stimulation and IL- 2, but this can lead to differentiation into effector T cells and lower therapeutic efficacy, whereas maintenance of a more stem-cell-like state before adoptive transfer is beneficial. Provided herein are recombinant IL-2 partial agonists that promote the expansion of CD8+T cells without driving terminal differentiation. Thus, alternatively, or in addition to methods of direct administration to patients, in some aspects, the disclosed recombinant IL-2 proteins or nucleic acid molecules encoding the recombinant IL-2 proteins can be used in ex vivo methods. For example, cells (e.g., peripheral blood lymphocytes, purified populations of lymphocytes isolated from a patient and placed or maintained in culture, or engineered cells such as CAR T cells) can be cultured in vitro in culture medium and the contacting step can be affected by adding the recombinant IL-2 protein or nucleic acid molecule encoding the recombinant IL-2 protein to the culture medium. The culture step can include further steps in which the cells are stimulated or treated with other agents, e.g., to stimulate proliferation, or to expand a population of cells that is reactive to an antigen of interest (e.g., a cancer antigen or a viral antigen). The cells are then administered to the patient after they have been treated. In some aspects, the treated T cells persist longer following administration to a subject as compared to control T cells not incubated with the recombinant IL-2 protein, the nucleic acid molecule encoding the recombinant IL-2 protein, or the vector comprising the nucleic acid molecule. 4239-112594-02 EXAMPLES The following examples are provided to illustrate particular features of certain aspects of the disclosure, but the scope of the claims should not be limited to those features exemplified. Example 1 Materials and Methods This example illustrates materials and methods used for the following examples. Flow Cytometric Analysis of Intracellular Phospho-STAT5 CD25+YT-1 and CD25- YT-1 (described in Mitra et al., Immunity (2015) 42:826-38) natural killer-like cells were cultured in RPMI complete medium (RPMI 1640 medium with 10% fetal bovine serum (FBS), 2 mM L-glutamine, minimum non-essential amino acids, sodium pyruvate, 25 mM HEPES, and penicillin-streptomycin [GIBCO]) at 37°C in a humidified atmosphere with 5% CO2. Buffy coats were from healthy donors. Peripheral blood mononuclear cells (PBMCs) were isolated by gradient centrifugation using lymphocyte separation medium (MP Diagnostics). Cells were isolated with the human CD8+T cell isolation kit (Stem Cell Technologies). To pre-activate cells, 24-well plates were pre-coated with 2 μg / ml of plate-bound anti-CD3 mAb (BioXcell), cells were seeded at 1 × 106cells / ml in RPMI complete medium with 1 μg / ml soluble anti-CD28 mAb (BioXcell) for 2 days and then rested overnight in fresh medium. 5 x 105cells were plated in wells of a 96-well plate with RPMI medium containing serial dilutions of the IL-2 variants (as indicated in FIG.1). Cells were stimulated for 20 minutes at 37ºC, fixed by the addition of formaldehyde to 4%, incubated for 20 minutes at room temperature, and permeabilized with 100% ice-cold methanol for at least 1 hour at - 20°C. The fixed and permeabilized cells were washed twice with flow cytometry buffer (PBS with 1% BSA) and incubated with PE-conjugated anti-STAT5 pY694 (BD Biosciences) for 1 hour at room temperature. Cells were then washed twice in a flow cytometry buffer and mean fluorescence intensity (MFI) was quantified on a Fortessa flow cytometer (BD Biosciences, San Jose, CA) and analyzed with FlowJo (Tree Star, Inc., Ashland, OR). Dose-response curves were generated, using the GraphPad Prism data analysis software after subtracting the MFI of unstimulated cells. 4239-112594-02 Flow Cytometric Analysis of PBMCs from Healthy Donors and SLE Patients Buffy coats were from healthy donors. PBMCs were isolated by gradient centrifugation using lymphocyte separation medium (MP Diagnostics). PBMCs were seeded in 24-well plates at a concentration of 2 × 106cells / ml in RPMI complete medium with different concentrations of IL-2 variants (indicated in FIG.2). Cytokine was replenished every other day and cells were cultured for 7 days. On day 7, cells were collected and washed with PBS supplemented with 0.2% heat-inactivated human serum (Sigma) and incubated with live-dead dye (Aqua - Invitrogen) and different cocktails of a panel of fluorophore-labeled monoclonal antibodies recognizing CD3, CD4, CD8, CD16, and CD25 for 20 minutes at room temperature. After cell surface staining, the cells were washed once and fixed / permeabilized using the FoxP3 staining kit (eBioscience). After a 30-minute incubation at 4°C, the cells were washed with FoxP3 washing buffer and intracellularly stained with cocktails of fluorophore-labeled monoclonal antibodies targeting intracellular antigens (Ki67, Foxp3, and Granzyme B) for 20 minutes. The cells were washed and resuspended in PBS for flow cytometry analysis. The samples were acquired on a Fortessa flow cytometer and the data were analyzed using the FlowJo software platform as above. In Vivo Administration of Cytokines C57BL / 6J mice were maintained in specific pathogen-free housing. For profiling experiments, mice were administered injections of PBS or 30 μg IL-2 or IL-2-ET on days 0, 3, and 6. On day 7, spleens were harvested, and a single-cell suspension was generated. Cells were surface stained before fixation and permeabilization using the Foxp3 transcription factor buffer set (as described above). DSS-induced colitis Female C57BL / 6 mice (B6NTac, Taconic) aged 8–12 weeks were administered 3% dextran sulfate sodium (DSS) (Sigma Aldrich) in drinking water ad libitum for 5 days. Starting on day 1 of DSS treatment, mice were injected with cytokine or PBS control intraperitoneally (i.p.) every two days for a total of four injections. For flow cytometry and histological analysis, mice were euthanized by CO2asphyxiation on day 16. Colons were removed and flushed, 2–2.5 cm pieces of the most distal part of the colon were fixed in 10% buffered formalin for histology. Single-cell suspensions from the Mesenteric lymph nodes were stained with a cocktail of surface and intracellular antibodies to determine the frequency of CD8+T cells and Tregs. 4239-112594-02 B16 Tumor Model and Adoptive Cell Transfer Immunotherapy 0.5 million B16KVP melanoma cells were subcutaneously injected into C57BL / 6 mice. Ten days later, mice were sub-lethally irradiated (600 cGy), randomized, and injected intravenously with 10 million Pmel-1 cells that were treated with IL-2 or IL-2-ET for 8 days. Pmel-1 cells are purified CD8+T cells from Pmel-1 mice, preactivated with anti-CD3 and anti-CD28 for 48 hours, rested overnight, and then treated with 10 nM IL-2 or IL-2-ET for 8 days. The tumor area was measured every 2 or 3 days by an independent investigator in a double-blinded fashion and calculated as length × width. Mice with tumors approaching 400 mm2were defined as being at the endpoint and euthanized. A part of the transferred cells was analyzed for its phenotypic characteristics using flow cytometry (using the protocol described above) and single-cell RNA sequencing was performed using Single Cell 3’ (10X Genomics) as per the instruction manual. Example 2 Generation of IL-2 Muteins This example illustrates methods of generating IL-2 muteins. An array of IL-2 variants with either one, two, or three mutations at positions 18, 22, 126, and 130 was generated, as shown in Table 1. Table 1: IL-2 Muteins. Residue no. 18 22 126 130 Identified function y d y d Variants included a signal peptide (which is cleaved during production) followed by mouse serum albumin (MSA) and the IL-2 sequence (WT or mutated, as shown in Table 1), 4239-112594-02 and a His-tag to facilitate purification. Amino acid sequences for generated variants and controls used in Examples 2-4 include: WT (SEQ ID NO: 1); H9 (SEQ ID NO: 23); WT-ET (SEQ ID NO: 9), H9-ET (SEQ ID NO: 25), WT-RT (SEQ ID NO: 11), H9-RT (SEQ ID NO: 27), WT-TR (SEQ ID NO: 13), H9-TR (SEQ ID NO: 29), WT-ER (SEQ ID NO: 15), H9-ER (SEQ ID NO: 31), WT-RR (SEQ ID NO: 17), H9-RR (SEQ ID NO: 33), WT-R (SEQ ID NO: 19), H9-R (SEQ ID NO: 35), WT-RER (SEQ ID NO: 21), H9-RER (SEQ ID NO: 37). These proteins were made using a baculovirus system in insect cells (purified using the nickel-affinity slurry method followed by FPLC fractionation) and then aliquoted and stored at -80oC, as described in Mo et al. (Nature (2021) 597:544-48). The buffer used to reconstitute the proteins was 1X PBS. The disclosed IL-2 proteins can be also be produced in other systems, such as a mammalian system, for example 293 cells. Example 3 Properties of IL-2 Muteins This example illustrates unique properties of the IL-2 muteins disclosed herein. IL-2 binding to its receptor on target cells (CD8+T cells, NK cells, Tregs, etc.) results in signaling, including the phosphorylation of STAT5. Therefore, the functional relevance of the variants made in Example 2 was evaluated by assessing pSTAT5 on two human NK-like YT cell lines (one expressing CD25 and one not expressing CD25) and on primary human CD8+T cells from normal donors. YT cells were treated with 10-12M, 10-11M, 10-10M, 10-9M 10-8M, 10-7M or 10-6M of the IL-2 muteins described in Example 2 for 15 minutes, followed by fixation, permeabilization, and quantification of pSTAT5 by flow cytometry. As seen in FIGS.1B-1C, IL-2 and its variants induced various levels of pSTAT5 in both CD25+and CD25- YT cells. IL-2-ET and IL-2-TR particularly showed dependence on CD25 (i.e., they had limited activity on YT cells lacking CD25 and greater activity on YT cells expressing CD25 or on pre-activated human CD8+T cells). IL-2-RER was distinctive in that it showed an increased pSTAT5 as compared to IL-2 alone and thus had an elevated Emax. Preactivated human CD8+T cells were treated with 10-12M, 10-11M, 10-10M, 10-9M or 10-8M of the IL-2 muteins described in Example 2. The cells were human CD8+T cells from PBMCs from healthy donors. They were preactivated with anti-CD3+anti-CD28. The results corroborated with the cell line findings (FIG.1D). 4239-112594-02 Example 4 Functional Effects of IL-2 Muteins This example illustrates unique functional effects induced by treatment with the IL-2 muteins disclosed herein, and the therapeutic potential of IL-2 muteins disclosed herein for autoimmune disease. Human PBMCs from healthy donors were treated in vitro with varying concentrations (10-10M, 10-9M, 10-8M, or 10-7M) of the IL-2 muteins described in Example 2 every other day for 8 days to identify the functional effects of the muteins disclosed herein. Flow cytometric analysis was used to differentiate CD8+T cells, NK cells, and Tregs in the PBMC population, and Ki67 expression showed that IL-2 and IL-2-RER induced proliferation in CD8+T cells (FIG.2A), NK cells (FIG.2B), and Tregs (FIG.2C). Unexpectedly, IL-2-ET preferentially expanded Tregs (FIG.2C). This indicates that IL-2-ET preferentially acts on cells expressing CD25 and thus high-affinity IL-2 receptors (resting CD8+T cells and NK cells do not express CD25 and Tregs constitutively express CD25). This finding was confirmed by in vivo administration of IL-2-ET into mice. IL-2-ET, IL-2, or PBS control were administered intraperitoneally three times over seven days (FIG. 3A). IL-2-ET induced expansion of Tregs but not CD8+T cells, as compared to the expansion of both CD8+T cells and Tregs by IL-2 injection (FIGS.3B-3C). This indicates that IL-2-ET has potential as an immunotherapeutic that expands Tregs in autoimmune diseases. Next, a DSS-induced colitis mouse model was employed. Mice were given 3% DSS containing water for 5 days followed by normal water for 10 days. Cytokine injections (IL-2 or IL-2-ET or PBS) were given on days 1, 4, 7 and 10 (FIG.4A). Injection of IL-2-ET resulted in selective expansion of Tregs in the mesenteric lymph nodes (FIGS.4E-4F) and this correlated with reduced weight loss (on day 9) and less inflammation in the colon as seen by histology scoring as compared to IL-2 or PBS (FIGS.4B-4C). It was confirmed that IL-2-ET also preferentially expanded Tregs in PBMCs from patients with systemic lupus erythematosus (SLE). PBMCs from normal donors and SLE patients were treated with IL-2 or IL-2-ET. % T cells (FIG.5A), cell counts, FIG.5B), and Ki67 expression were assessed via flow cytometry on NK cells (FIG.5B), CD8+T cells (FIG. 5C), and Tregs (FIG.5D). This expansion of Tregs in SLE patients was equivalent to that observed in healthy donors. SLE is an autoimmune condition characterized by the generation of autoantibodies, self-reactive T cells, and lower lymphocyte count including loss of Treg 4239-112594-02 cells and increased neutrophils and monocytes. Expanding Treg numbers and function is a way to control / limit disease and thus IL-2-ET has potential therapeutic value in such diseases. Example 5 Functional Effects of IL-2 Muteins This example illustrates unique functional effects induced by treatment with the IL-2 muteins disclosed herein in the context of TCR-activated CD8+T cells and the therapeutic potential of IL-2 muteins disclosed herein for treatment of cancer. TCR-activated CD8+T cells or effector cells transiently express CD25 on their surface. Based on the results presented in Examples 3 and 4, the ability of IL-2-ET to act on preactivated (TCR-activated) CD8+T cells was investigated. To assess the effect of IL-2 versus IL-2-ET on these cells, CD8+T cells from Pmel-1 TCR transgenic mice (mice that have a TCR that recognizes the gp100 melanoma antigen) were cultured for 10 days in IL-2-ET as compared to IL-2. Cells cultured in IL-2-ET showed significantly lower expression of exhaustion markers (Tim3, Lag3, PD-1), activation markers (CD69 and CD39), but higher levels of TCF1, resulting in a more stem-like phenotype (FIGS.6A-6C). Pmel-1 CD8+T cells cultured in IL-2 versus IL-2-ET were transferred into B16 melanoma-bearing mice (10 million cells transferred / mouse). There was significantly greater anti-tumor activity of cells cultured with IL-2-ET than with IL-2, with a greater percentage of tumor-free mice (FIG.7A-7C). A similar profile of lower exhaustion markers and more stem- like features in preactivated human CD8+T cells cultured with IL-2-ET as compared to IL-2. Example 6 In vivo administration of IL-2-ET rescues NOD mice from developing type-1 diabetes Given the effect of IL-2-ET on expanding Tregs, it was hypothesized that this engineered cytokine might have potential as an immunotherapeutic in autoimmune disease. NOD mice are genetically predisposed to type-1 autoimmune diabetes (T1D), which can occur as early as 3 weeks of age, with a median onset at week 16 for their female counterparts. The pathogenesis of T1D involves excessive infiltration of effector T cells and NK cells into the pancreas, which limits Treg function by augmenting the effector-to- regulatory T cell ratio. Daily low-dose IL-2 treatment has been shown to significantly protect from T1D development, whereas frequent high-dose IL-2 treatment actually accelerated disease by 4239-112594-02 potentiating effector T cell and NK cell responses (Tang et al., Immunity 28(5):687-697, 2008). Thus, this model can be used to determine whether a cytokine like IL-2-ET, which can more selectively expand Treg cells, has improved therapeutic efficacy. Therefore, NOD mice were treated (beginning at 9 weeks and ending at 17 weeks of age) with multiple doses of IL- 2 or IL-2-ET, or PBS as depicted in FIG.8A, and blood glucose levels were monitored until 34 weeks of age. By 20 weeks, 90% of the PBS-treated control mice developed diabetes, and the IL-2-treated group developed T1D even more rapidly, as assessed by blood glucose levels (FIG.8B). In contrast, treatment with IL-2-ET protected against the development of T1D. This indicates that IL-2-ET protects against T1D at a dose where IL-2 is detrimental. A significant increase in CD8+T cells was observed in the IL-2-treated mice in the pancreas, pancreatic lymph node, and spleen (FIG.8C). Moreover, IL-2 treatment also slightly increased Treg cells population as compared to PBS (FIG.8D). In contrast, the pancreas, pancreatic lymph node, and spleen of IL-2-ET-treated mice did not show an increase in CD8+T cells but showed a marked expansion of Tregs (FIGS.8C-8D). Histology sections of the pancreas on week 12 showed intact islet architecture in the IL-2-ET mice, whereas in PBS and more dramatically in IL-2-treated mice, sections showed immune cell infiltration in the islets and overall inflammation in the pancreas (FIG.8E). Thus, IL-2-ET treatment resulted in efficient, targeted, and sustained control of autoimmunity, and importantly, at a dose where IL-2 ameliorates autoimmunity. Methods Six-week-old NOD / ShiLTJ female mice were received from The Jackson Laboratory. At week 9, mice received IP injections of IL-2 or IL-2-ET or PBS at the indicated times shown in FIG.8A. Blood glucose levels and body weight were measured weekly. Diabetes was confirmed when blood glucose was above 250 mg / dL for two consecutive days. At week 14, five mice from each group were sacrificed, and spleens, pancreatic lymph nodes (pLN), and pancreas were harvested. Single cell suspensions from spleen and lymph nodes were prepared by mechanical disruption and filtered through a 70 μm strainer. Pancreas was digested enzymatically in RPMI medium supplemented with DNase I (1:200) and liberase TM (1:100) for 30 minutes at 37°C under agitation. Cell suspensions were filtered through a 70 μm strainer, and single cell suspensions from spleen pLN, and pancreas were used for flow cytometry analysis. Part of the pancreas was fixed in 10% neutral buffered formalin and embedded in paraffin. Five μm sections (three / mouse, 200 μm apart) were stained with hematoxylin and eosin. Islets were scored by a pathologist for the severity of insulitis on a 4239-112594-02 scale of 0–3 (0, no infiltration; 1, peri-islet infiltration; 2, <50% islet infiltration; and 3, >50% infiltration) using a Leica DM2500 microscope. It will be apparent that the precise details of the methods or compositions described may be varied or modified without departing from the spirit of the described aspects of the disclosure. We claim all such modifications and variations that fall within the scope and spirit of the claims below.

Claims

4239-112594-02CLAIMS 1. A recombinant IL-2 protein, comprising amino acid substitutions as follows: Q22E and Q126T; L18R, Q22E, and S130R; L18R and Q126T; or Q126T and S130R, wherein the amino acid numbering is according to the reference IL-2 protein sequence set forth as SEQ ID NO:

6.

2. The recombinant IL-2 protein of claim 1, further comprising L80F, R81D, L85V, I86V, and I92F amino acid substitutions.

3. The recombinant IL-2 protein of claim 1 or claim 2, comprising the Q22E and Q126T amino acid substitutions.

4. The recombinant IL-2 protein of claim 3, comprising the Q22E and Q126T amino acid substitutions and an amino acid sequence at least 80% identical to SEQ ID NO: 8 or SEQ ID NO:

24.

5. The recombinant IL-2 protein of claim 3, comprising an amino acid sequence set forth as SEQ ID NO: 8 or SEQ ID NO:

24.

6. The recombinant IL-2 protein of claim 1 or claim 2, comprising the L18R, Q22E, and S130R amino acid substitutions.

7. The recombinant IL-2 protein of claim 6, comprising the L18R, Q22E, and S130R amino acid substitutions and an amino acid sequence at least 80% identical to SEQ ID NO: 20 or SEQ ID NO:

36.

8. The recombinant IL-2 protein of claim 6, comprising an amino acid sequence set forth as SEQ ID NO: 20 or SEQ ID NO:

36.

9. The recombinant IL-2 protein of claim 1 or claim 2, comprising the L18R and Q126T amino acid substitutions.4239-112594-0210. The recombinant IL-2 protein of claim 9, comprising the L18R and Q126T amino acid substitutions and an amino acid sequence at least 80% identical to SEQ ID NO: 10 or SEQ ID NO:

26.

11. The recombinant IL-2 protein of claim 9, comprising an amino acid sequence set forth as SEQ ID NO: 10 or SEQ ID NO:

26.

12. The recombinant IL-2 protein of claim 1 or claim 2, comprising the Q126T and S130R amino acid substitutions.

13. The recombinant IL-2 protein of claim 12, comprising the Q126T and S130R amino acid substitutions and an amino acid sequence at least 80% identical to SEQ ID NO: 12 or SEQ ID NO:

28.

14. The recombinant IL-2 protein of claim 12, comprising an amino acid sequence set forth as SEQ ID NO: 12 or SEQ ID NO:

28.

15. The recombinant IL-2 protein of any one of claims 1-5 and 9-14, comprising the Q22E and Q126T amino acid substitutions, the L18R and Q126T amino acid substitutions, or the Q126T and S130R amino acid substitutions, wherein: the recombinant IL-2 protein has a reduced capability to stimulate STAT5 phosphorylation in T cells as compared to wild-type human IL-2; and / or the recombinant IL-2 protein induces lower proliferation of CD8+T cells and greater proliferation of Treg cells as compared to wild-type human IL-2 when incubated with peripheral blood mononuclear cells (PBMCs).

16. The recombinant IL-2 protein of any one of claims 1-2 and 6-8, comprising the L18R, Q22E, and S130R amino acid substitutions, wherein the recombinant IL-2 protein has an increased capability to stimulate STAT5 phosphorylation in T cells as compared to wild-type human IL-2.

17. The recombinant IL-2 protein of any one of claims 1-16, wherein the recombinant IL-2 protein is a human IL-2 protein comprising the amino acid substitutions.4239-112594-0218. The recombinant IL-2 protein of any one of claims 1-17, linked or fused to a heterologous protein.

19. The recombinant IL-2 protein of claim 18, wherein the heterologous protein is a human Fc antibody fragment, human serum albumin, or mouse serum albumin.

20. A multimer of the recombinant IL-2 protein of any one of claims 1-19.

21. A nucleic acid molecule encoding the recombinant IL-2 protein of any one of claims 1-19 or the multimer of claim 20.

22. The nucleic acid molecule of claim 21, operably linked to a promoter.

23. The nucleic acid molecule of claim 21, wherein the nucleic acid molecule is an RNA molecule.

24. A vector comprising the nucleic acid molecule of any one of claims 21-23.

25. The vector of claim 24, wherein the vector is a viral vector.

26. A host cell comprising the nucleic acid molecule or vector of any one of claims 21-25.

27. A method of producing a recombinant IL-2 protein, comprising: expressing the nucleic acid molecule or vector of any one of claims 21-25 in a host cell; and purifying the recombinant IL-2 protein.

28. A pharmaceutical composition comprising the recombinant IL-2 protein of any one of claims 1-19, the multimer of claim 20, the nucleic acid molecule of any one of claims 21-23, or the vector of claim 24 or claim 25, and a pharmaceutically acceptable carrier.4239-112594-0229. A method of treating an autoimmune disease in a subject, comprising administering to a subject in need thereof a therapeutically effective amount of the recombinant IL-2 protein of any one of claims 1-19, the multimer of claim 20, the nucleic acid molecule of any one of claims 21-23, or the vector of claim 24 or claim 25, to treat the autoimmune disease in the subject.

30. The method of claim 29, wherein the autoimmune disease is selected from any one of systemic lupus erythematosus, colitis, ulcerative colitis, rheumatoid arthritis, ankylosing spondylitis, psoriasis, Behçet’s disease, granulomatosis with polyangiitis, Takayasu’s arteritis, Crohn’s disease, , autoimmune hepatitis, sclerosing cholangitis, Sjogren’s Syndrome, and systemic sclerosis.

31. A method of treating cancer in a subject, comprising culturing T cells or NK cells with an effective amount of the recombinant IL-2 protein of any one of claims 1-19, the multimer of claim 20, the nucleic acid molecule of any one of claims 21-23, or the vector of claim 24 or claim 25, thereby expanding the T cells; and adoptively transferring the expanded T cells to the subject to treat the cancer.

32. The method of claim 31, wherein the T cells are CD8+ T cells and / or chimeric antigen receptor (CAR) T cells.

33. The method of claim 31 or claim 32, wherein the cancer is melanoma.

34. A method of expanding T cells or NK cells, comprising incubating the T cells or NK cells with an amount of the recombinant IL-2 protein of any one of claims 1-19, the multimer of claim 20, the nucleic acid molecule of any one of claims 21-23, or the vector of claim 24 or claim 25, effective to induce proliferation of the T cells.

35. The method of claim 34, wherein the T cells are selected from total T cells, CD8+T cells, CD4+T cells, Treg cells, and CAR T cells.

36. The method of claim 34 or claim 35, wherein: the T cells or NK cells undergo less differentiation following incubation with the recombinant IL-2 protein, the multimer, the nucleic acid molecule encoding the recombinant4239-112594-02IL-2 protein, or the vector comprising the nucleic acid molecule, as compared to control T cells or NK cells incubated with wild-type IL-2; and / or the T cells or NK cells persist longer following administration to a subject as compared to control T cells or NK cells not incubated with the recombinant IL-2 protein, the multimer, the nucleic acid molecule encoding the recombinant IL-2 protein, or the vector comprising the nucleic acid molecule.

37. The method of any one of claims 34-37, further comprising administering the T cells or NK cells to a patient in need thereof as an adoptive cell transfer therapy.

38. The method of claim 37, wherein the patient has cancer.

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