IL-2 conjugate and method of using the same

Abstract

Disclosed herein are compositions, kits, and methods comprising interleukin (IL) conjugates (e.g., IL-2 conjugates) useful for treating one or more indications. Pharmaceutical compositions and kits comprising one or more of the interleukin conjugates (e.g., IL-2 conjugates) are also described herein.

Description

Technical Field

[0001] Cross-reference This application claims the benefit of U.S. Provisional Patent Application No. 62 / 802,191, filed Feb. 6, 2019; U.S. Provisional Patent Application No. 62 / 847,844, filed May 14, 2019; U.S. Provisional Patent Application No. 62 / 870,581, filed Jul. 3, 2019; U.S. Provisional Patent Application No. 62 / 899,035, filed Sep. 11, 2019; and U.S. Provisional Patent Application No. 62 / 940,173, filed Nov. 25, 2019, the entire contents of each of which are incorporated herein by reference.

[0002] Sequence Listing This application includes a Sequence Listing that has been electronically submitted in ASCII format and is hereby incorporated by reference in its entirety. The ASCII copy was created on Feb. 4, 2020, is named 46085-729_601_SL.txt, and is 124,806 bytes in size.

Background Art

[0003] Separate populations of T cells regulate the immune system to maintain immune homeostasis and immune tolerance. For example, regulatory T (Treg) cells prevent inappropriate responses by the immune system by preventing pathogenic autoreactivity, while cytotoxic T cells target and destroy infected and / or cancerous cells. In some instances, the regulation of different populations of T cells provides options for the treatment of diseases or conditions.

Summary of the Invention

Means for Solving the Problems

[0004] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (I):

Chemical Formula

[0005] X has the structure: [Chemical formula] (having) is an IL-2 conjugate replaced at [Chemical formula] , or a pharmaceutically acceptable salt, solvate, or hydrate thereof. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, Z is CH2 and Y is [Chemical formula] ​is as follows. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, Z is CH2 and Y is [Chemical formula] is as follows. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, Z is CH2 and Y is [Chemical formula] is as follows. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, Y is CH2 and Z is [Chemical formula] is. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the PEG group has an average molecular weight selected from 5 kDa, 10 kDa, 20 kDa, and 30 kDa. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the PEG group has an average molecular weight of 5 kDa. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the PEG group has an average molecular weight of 10 kDa. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the PEG group has an average molecular weight of 15 kDa. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the PEG group has an average molecular weight of 20 kDa. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the PEG group has an average molecular weight of 25 kDa. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the PEG group has an average molecular weight of 30 kDa. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the PEG group has an average molecular weight of 35 kDa. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the PEG group has an average molecular weight of 40 kDa. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the PEG group has an average molecular weight of 45 kDa. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the PEG group has an average molecular weight of 50 kDa.In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the PEG group has an average molecular weight of 60 kDa. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is selected from K35, F42, F44, K43, E62, P65, R38, T41, E68, Y45, V69, and L72, and the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is based on the positions of SEQ ID NO: 1. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is selected from F42, E62, and P65, and the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is based on the positions of SEQ ID NO: 1. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is K35, and the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is based on the positions of SEQ ID NO: 1. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is F42, and the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is based on the positions of SEQ ID NO: 1. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is F44, and the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is based on the positions of SEQ ID NO: 1.In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is K43, and the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is based on the position of SEQ ID NO: 1. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is E62, and the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is based on the position of SEQ ID NO: 1. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is P65, and the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is based on the position of SEQ ID NO: 1. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is R38, and the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is based on the position of SEQ ID NO: 1. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is T41, and the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is based on the position of SEQ ID NO: 1. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is E68, and the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is based on the position of SEQ ID NO: 1.In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is Y45, and the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is based on the position of SEQ ID NO: 1. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is V69, and the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is based on the position of SEQ ID NO: 1. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is L72, and the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is based on the position of SEQ ID NO: 1.

[0006] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 4, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (I):

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[0007] Described herein is an IL-2 conjugate comprising any one of the amino acid sequences of SEQ ID NOs: 15 to 19, wherein [AzK_PEG] has the structure of formula (II) or formula (III), or a mixture of formula (II) and formula (III):

Chemical formula

[0008] X has the structure:

Chemical formula

[0009] In some embodiments of the IL-2 conjugates described herein having an amino acid sequence selected from any one of SEQ ID NOs: 15, 16, 17, 18, and 19, [AzK_PEG] contains a PEG group having an average molecular weight selected from 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, and 60 kDa. In some embodiments of the IL-2 conjugates described herein having an amino acid sequence selected from any one of SEQ ID NOs: 15, 16, 17, 18, and 19, [AzK_PEG] contains a PEG group having an average molecular weight of 5 kDa. In some embodiments of the IL-2 conjugates described herein having an amino acid sequence selected from any one of SEQ ID NOs: 15, 16, 17, 18, and 19, [AzK_PEG] contains a PEG group having an average molecular weight of 10 kDa. In some embodiments of the IL-2 conjugates described herein having an amino acid sequence selected from any one of SEQ ID NOs: 15, 16, 17, 18, and 19, [AzK_PEG] contains a PEG group having an average molecular weight of 15 kDa. In some embodiments of the IL-2 conjugates described herein having an amino acid sequence selected from any one of SEQ ID NOs: 15, 16, 17, 18, and 19, [AzK_PEG] contains a PEG group having an average molecular weight of 20 kDa. In some embodiments of the IL-2 conjugates described herein having an amino acid sequence selected from any one of SEQ ID NOs: 15, 16, 17, 18, and 19, [AzK_PEG] contains a PEG group having an average molecular weight of 25 kDa. In some embodiments of the IL-2 conjugates described herein having an amino acid sequence selected from any one of SEQ ID NOs: 15, 16, 17, 18, and 19, [AzK_PEG] contains a PEG group having an average molecular weight of 30 kDa. In some embodiments of the IL-2 conjugates described herein having an amino acid sequence selected from any one of SEQ ID NOs: 15, 16, 17, 18, and 19, [AzK_PEG] contains a PEG group having an average molecular weight of 35 kDa.In some embodiments of the IL-2 conjugates described herein having an amino acid sequence selected from any one of SEQ ID NOs: 15, 16, 17, 18, and 19, [AzK_PEG] contains a PEG group having an average molecular weight of 40 kDa. In some embodiments of the IL-2 conjugates described herein having an amino acid sequence selected from any one of SEQ ID NOs: 15, 16, 17, 18, and 19, [AzK_PEG] contains a PEG group having an average molecular weight of 45 kDa. In some embodiments of the IL-2 conjugates described herein having an amino acid sequence selected from any one of SEQ ID NOs: 15, 16, 17, 18, and 19, [AzK_PEG] contains a PEG group having an average molecular weight of 50 kDa. In some embodiments of the IL-2 conjugates described herein having an amino acid sequence selected from any one of SEQ ID NOs: 15, 16, 17, 18, and 19, [AzK_PEG] contains a PEG group having an average molecular weight of 60 kDa. In some embodiments of the IL-2 conjugates described herein having an amino acid sequence selected from any one of SEQ ID NOs: 15, 16, 17, 18, and 19, [AzK_PEG] contains a PEG group having an average molecular weight selected from 5 kDa, 10 kDa, 15 kDa, 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, and 60 kDa, and the PEG group is a methoxy PEG group, a linear methoxy PEG group, or a branched methoxy PEG group.

[0010] Described herein is an IL-2 conjugate comprising an amino acid sequence of any one of SEQ ID NOs: 20-24, wherein [AzK_PEG5kD] has the structure of formula (II) or formula (III), or a mixture of formula (II) and formula (III):

Chemical formula

[0011] X has the structure: [Chem.] An IL-2 conjugate having (having); or a pharmaceutically acceptable salt, solvate, or hydrate thereof. In some embodiments of the IL-2 conjugate, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, described herein, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 20. In some embodiments of the IL-2 conjugate, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, described herein, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 21. In some embodiments of the IL-2 conjugate, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, described herein, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 22. In some embodiments of the IL-2 conjugate, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, described herein, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 23. In some embodiments of the IL-2 conjugate, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, described herein, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 24. In some embodiments of the IL-2 conjugate; or a pharmaceutically acceptable salt, solvate, or hydrate thereof, described herein, [AzK_PEG5kD] has the structure of formula (II) [Chem.] It has. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 20. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 21. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 22. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 23. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 24. In some embodiments of the IL-2 conjugate described herein; or a pharmaceutically acceptable salt, solvate, or hydrate thereof, [AzK_PEG5kD] has the structure of formula (III) [Chemical formula] It has. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 20. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 21. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 22. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 23. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 24.

[0012] Described herein is an IL-2 conjugate comprising any one of the amino acid sequences of SEQ ID NOs: 25 to 29, wherein [AzK_PEG30kD] has the structure of formula (II) or formula (III), or is a mixture of the structures of formula (II) and formula (III):

Chemical formula

[0013] X is the structure:

Chemical formula

[0014] Described herein is an IL-2 conjugate comprising any one of the amino acid sequences of SEQ ID NOs: 15 to 19, wherein [AzK_PEG] is a mixture of the structures of formula (II) and formula (III):

Chemical formula

[0015] X is the structure:

Chemical formula

[0016] Described herein is an IL-2 conjugate comprising any one of the amino acid sequences of SEQ ID NOs: 20-24, wherein [AzK_PEG5kD] is a mixture of the structures of formula (II) and formula (III): [Chemical Structure] (Wherein: W is a PEG group having an average molecular weight of 5 kDa;

[0017] X has the structure: [Chemical Structure] ) and is an IL-2 conjugate; or a pharmaceutically acceptable salt, solvate, or hydrate thereof. In some embodiments of the IL-2 conjugate described herein, the ratio of the amount of the structure of formula (II) to the amount of the structure of formula (III), including the total amount of [AzK_PEG5kD] in the IL-2 conjugate, is about 1:1. In some embodiments of the IL-2 conjugate described herein, the ratio of the amount of the structure of formula (II) to the amount of the structure of formula (III), including the total amount of [AzK_PEG5kD] in the IL-2 conjugate, is greater than 1:1. In some embodiments of the IL-2 conjugate described herein, the ratio of the amount of the structure of formula (II) to the amount of the structure of formula (III), including the total amount of [AzK_PEG5kD] in the IL-2 conjugate, is less than 1:1.

[0018] Described herein is an IL-2 conjugate comprising any one of the amino acid sequences of SEQ ID NOs: 25-29, wherein [AzK_PEG30kD] is a mixture of the structures of formula (II) and formula (III): [Chemical Structure] (Wherein: W is a PEG group having an average molecular weight of 30 kDa;

[0019] X has the structure: [Chemical Structure] having), an IL-2 conjugate; or a pharmaceutically acceptable salt, solvate, or hydrate thereof. In some embodiments of the IL-2 conjugates described herein, the ratio of the amount of the structure of formula (II) to the amount of the structure of formula (III), including the total amount of [AzK_PEG30kD] in the IL-2 conjugate, is about 1:1. In some embodiments of the IL-2 conjugates described herein, the ratio of the amount of the structure of formula (II) to the amount of the structure of formula (III), including the total amount of [AzK_PEG30kD] in the IL-2 conjugate, is greater than 1:1. In some embodiments of the IL-2 conjugates described herein, the ratio of the amount of the structure of formula (II) to the amount of the structure of formula (III), including the total amount of [AzK_PEG30kD] in the IL-2 conjugate, is less than 1:1.

[0020] Described herein is an IL-2 conjugate comprising any one amino acid sequence of SEQ ID NOs: 40 to 44, wherein [AzK_L1_PEG] has the structure of formula (IV) or formula (V), or a mixture of formula (IV) and formula (V):

Chemical formula

[0021] X has the structure:

Chemical formula

[0022] Described herein is an IL-2 conjugate comprising an amino acid sequence of any one of SEQ ID NOs: 45 to 49, wherein [AzK_L1_PEG5kD] has the structure of formula (IV) or formula (V), or a mixture of formula (IV) and formula (V): [Chemical formula] (wherein: W is a PEG group having an average molecular weight of 5 kDa;

[0023] X has the structure: [Chemical formula] and is an IL-2 conjugate; or a pharmaceutically acceptable salt, solvate, or hydrate thereof. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 45. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 46. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 47. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 48. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 49. In some embodiments of the IL-2 conjugate described herein, [AzK_L1_PEG5kD] has the structure of formula (IV) [Chemical formula] or a pharmaceutically acceptable salt, solvate, or hydrate thereof. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 45. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 46. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 47. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 48. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 49. In some embodiments of the IL-2 conjugate described herein, [AzK_L1_PEG5kD] has the structure of formula (V) [Chemical Formula] or a pharmaceutically acceptable salt, solvate, or hydrate thereof. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 45. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 46. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 47. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 48. In some embodiments of the IL-2 conjugate described herein, or a pharmaceutically acceptable salt, solvate, or hydrate thereof, the IL-2 conjugate has the amino acid sequence of SEQ ID NO: 49.

[0024] Described herein is an IL-2 conjugate comprising any one of the amino acid sequences of SEQ ID NOs: 50 to 54, wherein [AzK_L1_PEG30kD] has the structure of formula (IV) or formula (V), or is a mixture of the structures of formula (IV) and formula (V):

Chemical formula

[0025] X is the structure:

Chemical formula

[0026] Described herein is an IL-2 conjugate comprising any one of the amino acid sequences of SEQ ID NOs: 40 to 44, wherein [Azk_L1_PEG] is a mixture of the structures of formula (IV) and formula (V):

Chemical formula

[0027] X is the structure:

Chemical formula

[0028] Disclosed herein is an IL-2 conjugate comprising any one of the amino acid sequences of SEQ ID NOs: 45 to 49, wherein [AzK_L1_PEG5kD] is a mixture of the structures of formula (IV) and formula (V):

Chemical formula

[0029] X is the structure:

Chemical formula

[0030] Disclosed herein is an IL-2 conjugate comprising any one of the amino acid sequences of SEQ ID NOs: 50 to 54, wherein [AzK_L1_PEG30kD] is a mixture of the structures of formula (IV) and formula (V):

Chemical formula

[0031] X is the structure:

Chemical formula

[0032] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (VI) or (VII), or a mixture of (VI) and (VII):

Chemical formula

[0033] X is

Chemical formula

[0034] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), and the amino acid residue in SEQ ID NO:3 to be replaced is selected from K34, F41, F43, K42, E61, P64, R37, T40, E67, Y44, V68, and L71, and n is an integer of 100 to about 1150, or about 100 to about 1100, or about 100 to about 1000, or about 100 to about 900, or about 100 to about 750, or about 100 to about 700, or about 100 to about 600, or about 100 to about 575, or about 100 to about 500, or about 100 to about 450, or about 100 to about 350, or about 100 to about 275, or about 100 to about 230, or about 150 to about 475, or about 150 to about 340, or about 113 to about 340, or about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 340 to about 795, or about 341 to about 682, or about 568 to about 909, or about 227 to about 1500, or about 225 to about 2280, or about 460 to about 2160, or about 460 to about 2050, or about 341 to about 1820, or about 341 to about 1710, or about 341 to about 1250, or about 225 to about 1250, or about 341 to about 1250, or about 341 to about 1136, or about 341 to about 1023, or about 341 to about 910, or about 341 to about 796, or about 341 to about 682, or about 341 to about 568, or about 114 to about 1000, or about 114 to about 950, or about 114 to about 910, or about 114 to about 800, or about 114 to about 690, or about 114 to about 575.In some embodiments of the IL-2 conjugates described herein, n in the compounds of formula (VI) and (VII) is an integer selected from 2, 5, 10, 11, 22, 23, 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, 1249, 1250, 1251, 1362, 1363, 1364, 1476, 1477, 1478, 1589, 1590, 1591, 1703, 1704, 1705, 1817, 1818, 1819, 1930, 1931, 1932, 2044, 2045, 2046, 2158, 2159, 2160, 2271, 2272, 2273, 2839, 2840, 2841, 2953, 2954, 2955, 3408, 3409, 3410, 3976, 3977, 3978, 4544, 4545, and 4546.

[0035] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), the amino acid residue in SEQ ID NO: 3 to be replaced is selected from F41, F43, K42, E61, and P64, and n is an integer of about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 568 to about 909. In some embodiments of the IL-2 conjugates described herein, n in the compounds of formula (VI) and (VII) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, and 1249.

[0036] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), the amino acid residue in SEQ ID NO:3 to be replaced is selected from E61 and P64, and n is an integer from about 450 to about 800, or from about 454 to about 796, or from about 454 to about 682, or from about 568 to about 909. In some embodiments of the IL-2 conjugate described herein, n in the compounds of formula (VI) and (VII) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910.

[0037] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), the amino acid residue in SEQ ID NO:3 to be replaced is E61, and n is an integer from about 450 to about 800, or from about 454 to about 796, or from about 454 to about 682, or from about 568 to about 909. In some embodiments of the IL-2 conjugate described herein, n in the compounds of formula (VI) and (VII) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910. In some embodiments, n is from about 500 to about 1000. In some embodiments, n is from about 550 to about 800. In some embodiments, n is about 681.

[0038] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), the amino acid residue in SEQ ID NO:3 to be replaced is P64, and n is an integer from about 450 to about 800, or from about 454 to about 796, or from about 454 to about 682, or from about 568 to about 909. In some embodiments of the IL-2 conjugates described herein, n in the compounds of formula (VI) and (VII) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910. In some embodiments, n is from about 500 to about 1000. In some embodiments, n is from about 550 to about 800. In some embodiments, n is about 681.

[0039] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), and n is such that the molecular weight of the PEG moiety is from about 1,000 Daltons to about 200,000 Daltons, or from about 2,000 Daltons to about 150,000 Daltons, or from about 3,000 Daltons to about 125,000 Daltons, or from about 4,000 Daltons to about 100,000 Daltons, or from about 5,000 Daltons to about 100,000 Daltons, or from about 6,000 Daltons to about 90,000 Daltons, or from about 7,000 Daltons to about 80,000 Daltons, or from about 8,000 Daltons to about 70,000 Daltons, or from about 5,000 Daltons to about 70,000 Daltons, or from about 5,000 Daltons to about 65,000 Daltons, or from about 5,000 Daltons to about 60,000 Daltons, or from about 5,000 Daltons to about 50,000 Daltons, or from about 6,000 Daltons to about 50,000 Daltons, or from about 7,000 Daltons to about 50,000 Daltons, or from about 7,000 Daltons to about 45,000 Daltons, or from about 7,000 Daltons to about 40,000 Daltons, or from about 8,000 Daltons to about 40,000 Daltons, or from about 8,500 Daltons to about 40,000 Daltons, or from about 8,500 Daltons to about 35,000 Daltons, or from about 9,000 Daltons to about 50,000 Daltons, or from about 9,000 Daltons to about 45,000 Daltons, or from about 9,000 Daltons to about 40,000 Daltons, or from about 9,000 Daltons to about 35,000 Daltons, or from about 9,000 Daltons to about 30,000 Daltons, or from about 9,500 Daltons to about 35,000 Daltons, or from about 9,500 Daltons to about 30,000 Daltons, or from about 10,000 Daltons to about 50,000 Daltons, or from about 10,000 Daltons to about 45,000 Daltons, or from about 10,000 Daltons to about 40,000 Daltons, or from about 10,000 Daltons to about 35,000 Daltons, or from about 10,000 Daltons to about 30,000 Daltons, or from about 15,000 Daltons to about 50,000 Daltons, or from about 15,000 Daltons to about 45,An integer in the range of 000 Daltons, or from about 15,000 Daltons to about 40,000 Daltons, or from about 15,000 Daltons to about 35,000 Daltons, or from about 15,000 Daltons to about 30,000 Daltons, or from about 20,000 Daltons to about 50,000 Daltons, or from about 20,000 Daltons to about 45,000 Daltons, or from about 20,000 Daltons to about 40,000 Daltons, or from about 20,000 Daltons to about 35,000 Daltons, or from about 20,000 Daltons to about 30,000 Daltons. Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), and n is an integer such that the molecular weight of the PEG moiety is about 5,000 Daltons, about 7,500 Daltons, about 10,000 Daltons, about 15,000 Daltons, about 20,000 Daltons, about 25,000 Daltons, about 30,000 Daltons, about 35,000 Daltons, about 40,000 Daltons, about 45,000 Daltons, about 50,000 Daltons, about 60,000 Daltons, about 70,000 Daltons, about 80,000 Daltons, about 90,000 Daltons, about 100,000 Daltons, about 125,000 Daltons, about 150,000 Daltons, about 175,000 Daltons or about 200,000 Daltons. Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (VI) or (VII), or a mixture of (VI) and (VII), and n is an integer such that the molecular weight of the PEG moiety is about 5,000 Daltons, about 7,500 Daltons, about 10,000 Daltons, about 15,000 Daltons, about 20,000 Daltons, about 25,000 Daltons, about 30,000 Daltons, about 35,000 Daltons, about 40,000 Daltons, about 45,000 Daltons, or about 50,000 Daltons.,

[0040] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX):

Chemical formula

[0041] X is

Chemical formula

[0042] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), and the amino acid residue in SEQ ID NO:3 to be replaced is selected from K34, F41, F43, K42, E61, P64, R37, T40, E67, Y44, V68, and L71, and n is an integer from 100 to about 1150, or about 100 to about 1100, or about 100 to about 1000, or about 100 to about 900, or about 100 to about 750, or about 100 to about 700, or about 100 to about 600, or about 100 to about 575, or about 100 to about 500, or about 100 to about 450, or about 100 to about 350, or about 100 to about 275, or about 100 to about 230, or about 150 to about 475, or about 150 to about 340, or about 113 to about 340, or about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 340 to about 795, or about 341 to about 682, or about 568 to about 909, or about 227 to about 1500, or about 225 to about 2280, or about 460 to about 2160, or about 460 to about 2050, or about 341 to about 1820, or about 341 to about 1710, or about 341 to about 1250, or about 225 to about 1250, or about 341 to about 1250, or about 341 to about 1136, or about 341 to about 1023, or about 341 to about 910, or about 341 to about 796, or about 341 to about 682, or about 341 to about 568, or about 114 to about 1000, or about 114 to about 950, or about 114 to about 910, or about 114 to about 800, or about 114 to about 690, or about 114 to about 575.In some embodiments of the IL-2 conjugates described herein, n in the compounds of formulas (VIII) and (IX) is an integer selected from 2, 5, 10, 11, 22, 23, 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, 1249, 1250, 1251, 1362, 1363, 1364, 1476, 1477, 1478, 1589, 1590, 1591, 1703, 1704, 1705, 1817, 1818, 1819, 1930, 1931, 1932, 2044, 2045, 2046, 2158, 2159, 2160, 2271, 2272, 2273, 2839, 2840, 2841, 2953, 2954, 2955, 3408, 3409, 3410, 3976, 3977, 3978, 4544, 4545, and 4546.

[0043] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), the amino acid residue in SEQ ID NO:3 to be replaced is selected from F41, F43, K42, E61, and P64, and n is an integer of about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 568 to about 909. In some embodiments of the IL-2 conjugates described herein, n in the compounds of formulas (VIII) and (IX) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, and 1249.

[0044] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), the amino acid residue in SEQ ID NO:3 to be replaced is selected from E61 and P64, and n is an integer from about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 568 to about 909. In some embodiments of the IL-2 conjugate described herein, n in the compounds of formula (VIII) and (IX) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910.

[0045] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), the amino acid residue in SEQ ID NO:3 to be replaced is E61, and n is an integer from about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 568 to about 909. In some embodiments of the IL-2 conjugate described herein, n in the compounds of formula (VIII) and (IX) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910. In some embodiments, n is from about 500 to about 1000. In some embodiments, n is from about 550 to about 800. In some embodiments, n is about 681.

[0046] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), the amino acid residue in SEQ ID NO:3 to be replaced is P64, and n is an integer from about 450 to about 800, or from about 454 to about 796, or from about 454 to about 682, or from about 568 to about 909. In some embodiments of the IL-2 conjugates described herein, n in the compounds of formula (VIII) and (IX) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910. In some embodiments, n is from about 500 to about 1000. In some embodiments, n is from about 550 to about 800. In some embodiments, n is about 681.

[0047] Disclosed herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), and n is such that the molecular weight of the PEG moiety is from about 1,000 Daltons to about 200,000 Daltons, or from about 2,000 Daltons to about 150,000 Daltons, or from about 3,000 Daltons to about 125,000 Daltons, or from about 4,000 Daltons to about 100,000 Daltons, or from about 5,000 Daltons to about 100,000 Daltons, or from about 6,000 Daltons to about 90,000 Daltons, or from about 7,000 Daltons to about 80,000 Daltons, or from about 8,000 Daltons to about 70,000 Daltons, or from about 5,000 Daltons to about 70,000 Daltons, or from about 5,000 Daltons to about 65,000 Daltons, or from about 5,000 Daltons to about 60,000 Daltons, or from about 5,000 Daltons to about 50,000 Daltons, or from about 6,000 Daltons to about 50,000 Daltons, or from about 7,000 Daltons to about 50,000 Daltons, or from about 7,000 Daltons to about 45,000 Daltons, or from about 7,000 Daltons to about 40,000 Daltons, or from about 8,000 Daltons to about 40,000 Daltons, or from about 8,500 Daltons to about 40,000 Daltons, or from about 8,500 Daltons to about 35,000 Daltons, or from about 9,000 Daltons to about 50,000 Daltons, or from about 9,000 Daltons to about 45,000 Daltons, or from about 9,000 Daltons to about 40,000 Daltons, or from about 9,000 Daltons to about 35,000 Daltons, or from about 9,000 Daltons to about 30,000 Daltons, or from about 9,500 Daltons to about 35,000 Daltons, or from about 9,500 Daltons to about 30,000 Daltons, or from about 10,000 Daltons to about 50,000 Daltons, or from about 10,000 Daltons to about 45,000 Daltons, or from about 10,000 Daltons to about 40,000 Daltons, or from about 10,000 Daltons to about 35,000 Daltons, or from about 10,000 Daltons to about 30,000 Daltons, or from about 15,000 Daltons to about 50,000 Daltons, or from about 15,000 Daltons to about 45,An integer in the range of 000 Daltons, or from about 15,000 Daltons to about 40,000 Daltons, or from about 15,000 Daltons to about 35,000 Daltons, or from about 15,000 Daltons to about 30,000 Daltons, or from about 20,000 Daltons to about 50,000 Daltons, or from about 20,000 Daltons to about 45,000 Daltons, or from about 20,000 Daltons to about 40,000 Daltons, or from about 20,000 Daltons to about 35,000 Daltons, or from about 20,000 Daltons to about 30,000 Daltons. Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (VIII) or (IX), or a mixture of (VIII) and (IX), and n is an integer such that the molecular weight of the PEG moiety is about 5,000 Daltons, about 7,500 Daltons, about 10,000 Daltons, about 15,000 Daltons, about 20,000 Daltons, about 25,000 Daltons, about 30,000 Daltons, about 35,000 Daltons, about 40,000 Daltons, about 45,000 Daltons, about 50,000 Daltons, about 60,000 Daltons, about 70,000 Daltons, about 80,000 Daltons, about 90,000 Daltons, about 100,000 Daltons, about 125,000 Daltons, about 150,000 Daltons, about 175,000 Daltons or about 200,000 Daltons. Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (VIII) or (XI), or a mixture of (VIII) and (IX), and n is an integer such that the molecular weight of the PEG moiety is about 5,000 Daltons, about 7,500 Daltons, about 10,000 Daltons, about 15,000 Daltons, about 20,000 Daltons, about 25,000 Daltons, about 30,000 Daltons, about 35,000 Daltons, about 40,000 Daltons, about 45,000 Daltons, or about 50,000 Daltons.,

[0048] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate has been replaced with a structure of formula (X) or (XI), or a mixture of (X) and (XI): [Chemical formula] (wherein: n is an integer in the range of about 2 to about 5000; The wavy line indicates a covalent bond to the amino acid residue in SEQ ID NO:3 that has not been replaced), or a pharmaceutically acceptable salt, solvate, or hydrate thereof.

[0049] In some embodiments, the stereochemistry of the chiral centers in formula (X) and formula (XI) is racemic, enriched in (R), enriched in (S), substantially (R), substantially (S), (R), or (S). In some embodiments, the stereochemistry of the chiral centers in formula (X) and formula (XI) is racemic. In some embodiments, the stereochemistry of the chiral centers in formula (X) and formula (XI) is enriched in (R). In some embodiments, the stereochemistry of the chiral centers in formula (X) and formula (XI) is enriched in (S). In some embodiments, the stereochemistry of the chiral centers in formula (X) and formula (XI) is substantially (R). In some embodiments, the stereochemistry of the chiral centers in formula (X) and formula (XI) is substantially (S). In some embodiments, the stereochemistry of the chiral centers in formula (X) and formula (XI) is (R). In some embodiments, the stereochemistry of the chiral centers in formula (X) and formula (XI) is (S).

[0050] In some embodiments of the IL-2 conjugates described herein, n in the compounds of formula (X) and (XI) is in the range of about 5 to about 4600, or about 10 to about 4000, or about 20 to about 3000, or about 100 to about 3000, or about 100 to about 2900, or about 150 to about 2900, or about 125 to about 2900, or about 100 to about 2500, or about 100 to about 2000, or about 100 to about 1900, or about 100 to about 1850, or about 100 to about 1750, or about 100 to about 1650, or about 100 to about 1500, or about 100 to about 1400, or about 100 to about 1300, or about 100 to about 1250, or about 100 to about 1150, or about 100 to about 1100, or about 100 to about 1000, or about 100 to about 900, or about 100 to about 750, or about 100 to about 700, or about 100 to about 600, or about 100 to about 575, or about 100 to about 500, or about 100 to about 450, or about 100 to about 350, or about 100 to about 275, or about 100 to about 230, or about 150 to about 475, or about 150 to about 340, or about 113 to about 340, or about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 340 to about 795, or about 341 to about 682, or about 568 to about 909, or about 227 to about 1500, or about 225 to about 2280, or about 460 to about 2160, or about 460 to about 2050, or about 341 to about 1820, or about 341 to about 1710, or about 341 to about 1250, or about 225 to about 1250, or about 341 to about 1250, or about 341 to about 1136, or about 341 to about 1023, or about 341 to about 910, or about 341 to about 796, or about 341 to about 682, or about 341 to about 568, or about 114 to about 1000, or about 114 to about 950, or about 114 to about 910, or about 114 to about 800, or about 114 to about 690, or about 114 to about 575.In some embodiments of the IL-2 conjugates described herein, n in the compounds of formula (X) and (XI) is an integer selected from 2, 5, 10, 11, 22, 23, 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, 1249, 1250, 1251, 1362, 1363, 1364, 1476, 1477, 1478, 1589, 1590, 1591, 1703, 1704, 1705, 1817, 1818, 1819, 1930, 1931, 1932, 2044, 2045, 2046, 2158, 2159, 2160, 2271, 2272, 2273, 2839, 2840, 2841, 2953, 2954, 2955, 3408, 3409, 3410, 3976, 3977, 3978, 4544, 4545, and 4546. In some embodiments of the IL-2 conjugates described herein, the positions of the structures of formula (X) and (XI), or a mixture of formula (X) and (XI), in the amino acid sequence of the IL-2 conjugate are selected from K34, F41, F43, K42, E61, P64, R37, T40, E67, Y44, V68, and L71, and the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is based on the position of SEQ ID NO: 3. In some embodiments of the IL-2 conjugates described herein, the positions of the structures of formula (X) and (XI), or a mixture of formula (X) and (XI), in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 are selected from K34, F41, F43, K42, E61, P64, R37, T40, E67, Y44, V68, and L71. In some embodiments of the IL-2 conjugates described herein, the positions of the structures of formula (X) and (XI), or a mixture of formula (X) and (XI), in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 are at position K34. In some embodiments of the IL-2 conjugates described herein, the positions of the structures of formula (X) and (XI), or a mixture of formula (X) and (XI), in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 are at position F41.In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (X) and (XI), or a mixture of formula (X) and (XI), in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position F43. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (X) and (XI), or a mixture of formula (X) and (XI), in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position K42. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (X) and (XI), or a mixture of formula (X) and (XI), in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position E61. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (X) and (XI), or a mixture of formula (X) and (XI), in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position P64. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (X) and (XI), or a mixture of formula (X) and (XI), in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position R37. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (X) and (XI), or a mixture of formula (X) and (XI), in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position T40. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (X) and (XI), or a mixture of formula (X) and (XI), in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position E67. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (X) and (XI), or a mixture of formula (X) and (XI), in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position Y44. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (X) and (XI), or a mixture of formula (X) and (XI), in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position V68.In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (X) and (XI), or a mixture of formula (X) and (XI), in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position L71. In some embodiments of the IL-2 conjugate described herein, the ratio of the amount of the structure of formula (X) to the amount of the structure of formula (XI), including the total amount of the IL-2 conjugate, is about 1:1. In some embodiments of the IL-2 conjugate described herein, the ratio of the amount of the structure of formula (X) to the amount of the structure of formula (XI), including the total amount of the IL-2 conjugate, is greater than 1:1. In some embodiments of the IL-2 conjugate described herein, the ratio of the amount of the structure of formula (X) to the amount of the structure of formula (XI), including the total amount of the IL-2 conjugate, is less than 1:1.

[0051] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (X) or (XI), or a mixture of (X) and (XI), and the amino acid residue in SEQ ID NO:3 to be replaced is selected from K34, F41, F43, K42, E61, P64, R37, T40, E67, Y44, V68, and L71, and n is an integer from 100 to about 1150, or about 100 to about 1100, or about 100 to about 1000, or about 100 to about 900, or about 100 to about 750, or about 100 to about 700, or about 100 to about 600, or about 100 to about 575, or about 100 to about 500, or about 100 to about 450, or about 100 to about 350, or about 100 to about 275, or about 100 to about 230, or about 150 to about 475, or about 150 to about 340, or about 113 to about 340, or about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 340 to about 795, or about 341 to about 682, or about 568 to about 909, or about 227 to about 1500, or about 225 to about 2280, or about 460 to about 2160, or about 460 to about 2050, or about 341 to about 1820, or about 341 to about 1710, or about 341 to about 1250, or about 225 to about 1250, or about 341 to about 1250, or about 341 to about 1136, or about 341 to about 1023, or about 341 to about 910, or about 341 to about 796, or about 341 to about 682, or about 341 to about 568, or about 114 to about 1000, or about 114 to about 950, or about 114 to about 910, or about 114 to about 800, or about 114 to about 690, or about 114 to about 575.In some embodiments of the IL-2 conjugates described herein, n in the compounds of formula (VI) and (VII) is an integer selected from 2, 5, 10, 11, 22, 23, 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, 1249, 1250, 1251, 1362, 1363, 1364, 1476, 1477, 1478, 1589, 1590, 1591, 1703, 1704, 1705, 1817, 1818, 1819, 1930, 1931, 1932, 2044, 2045, 2046, 2158, 2159, 2160, 2271, 2272, 2273, 2839, 2840, 2841, 2953, 2954, 2955, 3408, 3409, 3410, 3976, 3977, 3978, 4544, 4545, and 4546.

[0052] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (X) or (XI), or a mixture of (X) and (XI), the amino acid residue in SEQ ID NO:3 to be replaced is selected from F41, F43, K42, E61, and P64, and n is an integer of about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 568 to about 909. In some embodiments of the IL-2 conjugates described herein, n in the compounds of formula (X) and (XI) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, and 1249.

[0053] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (X) or (XI), or a mixture of (X) and (XI), the amino acid residue in SEQ ID NO:3 to be replaced is selected from E61 and P64, and n is an integer of about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 568 to about 909. In some embodiments of the IL-2 conjugate described herein, n in the compounds of formula (X) and (XI) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910.

[0054] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (X) or (XI), or a mixture of (X) and (XI), the amino acid residue in SEQ ID NO:3 to be replaced is E61, and n is an integer of about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 568 to about 909. In some embodiments of the IL-2 conjugate described herein, n in the compounds of formula (X) and (XI) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910. In some embodiments, n is about 500 to about 1000. In some embodiments, n is about 550 to about 800. In some embodiments, n is about 681.

[0055] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (X) or (XI), or a mixture of (X) and (XI), the amino acid residue in SEQ ID NO: 3 that is replaced is P64, and n is an integer from about 450 to about 800, or from about 454 to about 796, or from about 454 to about 682, or from about 568 to about 909. In some embodiments of the IL-2 conjugate described herein, n in the compounds of formula (X) and (XI) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910. In some embodiments, n is from about 500 to about 1000. In some embodiments, n is from about 550 to about 800. In some embodiments, n is about 681.

[0056] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (X) or (XI), or a mixture of (X) and (XI), and n is such that the molecular weight of the PEG moiety is from about 1,000 Daltons to about 200,000 Daltons, or from about 2,000 Daltons to about 150,000 Daltons, or from about 3,000 Daltons to about 125,000 Daltons, or from about 4,000 Daltons to about 100,000 Daltons, or from about 5,000 Daltons to about 100,000 Daltons, or from about 6,000 Daltons to about 90,000 Daltons, or from about 7,000 Daltons to about 80,000 Daltons, or from about 8,000 Daltons to about 70,000 Daltons, or from about 5,000 Daltons to about 70,000 Daltons, or from about 5,000 Daltons to about 65,000 Daltons, or from about 5,000 Daltons to about 60,000 Daltons, or from about 5,000 Daltons to about 50,000 Daltons, or from about 6,000 Daltons to about 50,000 Daltons, or from about 7,000 Daltons to about 50,000 Daltons, or from about 7,000 Daltons to about 45,000 Daltons, or from about 7,000 Daltons to about 40,000 Daltons, or from about 8,000 Daltons to about 40,000 Daltons, or from about 8,500 Daltons to about 40,000 Daltons, or from about 8,500 Daltons to about 35,000 Daltons, or from about 9,000 Daltons to about 50,000 Daltons, or from about 9,000 Daltons to about 45,000 Daltons, or from about 9,000 Daltons to about 40,000 Daltons, or from about 9,000 Daltons to about 35,000 Daltons, or from about 9,000 Daltons to about 30,000 Daltons, or from about 9,500 Daltons to about 35,000 Daltons, or from about 9,500 Daltons to about 30,000 Daltons, or from about 10,000 Daltons to about 50,000 Daltons, or from about 10,000 Daltons to about 45,000 Daltons, or from about 10,000 Daltons to about 40,000 Daltons, or from about 10,000 Daltons to about 35,000 Daltons, or from about 10,000 Daltons to about 30,000 Daltons, or from about 15,000 Daltons to about 50,000 Daltons, or from about 15,000 Daltons to about 45,An integer in the range of 000 Daltons, or from about 15,000 Daltons to about 40,000 Daltons, or from about 15,000 Daltons to about 35,000 Daltons, or from about 15,000 Daltons to about 30,000 Daltons, or from about 20,000 Daltons to about 50,000 Daltons, or from about 20,000 Daltons to about 45,000 Daltons, or from about 20,000 Daltons to about 40,000 Daltons, or from about 20,000 Daltons to about 35,000 Daltons, or from about 20,000 Daltons to about 30,000 Daltons. Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (X) or (XI), or a mixture of (X) and (XI), and n is an integer such that the molecular weight of the PEG moiety is about 5,000 Daltons, about 7,500 Daltons, about 10,000 Daltons, about 15,000 Daltons, about 20,000 Daltons, about 25,000 Daltons, about 30,000 Daltons, about 35,000 Daltons, about 40,000 Daltons, about 45,000 Daltons, about 50,000 Daltons, about 60,000 Daltons, about 70,000 Daltons, about 80,000 Daltons, about 90,000 Daltons, about 100,000 Daltons, about 125,000 Daltons, about 150,000 Daltons, about 175,000 Daltons or about 200,000 Daltons. Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (X) or (XI), or a mixture of (X) and (XI), and n is an integer such that the molecular weight of the PEG moiety is about 5,000 Daltons, about 7,500 Daltons, about 10,000 Daltons, about 15,000 Daltons, about 20,000 Daltons, about 25,000 Daltons, about 30,000 Daltons, about 35,000 Daltons, about 40,000 Daltons, about 45,000 Daltons, or about 50,000 Daltons.,

[0057] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate has been replaced with the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII): [Chemical formula] (wherein: n is an integer in the range of about 2 to about 5000; The wavy line indicates a covalent bond to an amino acid residue within SEQ ID NO: 3 that has not been replaced), or a pharmaceutically acceptable salt, solvate, or hydrate thereof.

[0058] In some embodiments, the stereochemistry of the chiral centers in formula (XII) and formula (XIII) is racemic, rich in (R), rich in (S), substantially (R), substantially (S), (R), or (S). In some embodiments, the stereochemistry of the chiral centers in formula (XII) and formula (XIII) is racemic. In some embodiments, the stereochemistry of the chiral centers in formula (XII) and formula (XIII) is rich in (R). In some embodiments, the stereochemistry of the chiral centers in formula (XII) and formula (XIII) is rich in (S). In some embodiments, the stereochemistry of the chiral centers in formula (XII) and formula (XIII) is substantially (R). In some embodiments, the stereochemistry of the chiral centers in formula (XII) and formula (XIII) is substantially (S). In some embodiments, the stereochemistry of the chiral centers in formula (XII) and formula (XIII) is (R). In some embodiments, the stereochemistry of the chiral centers in formula (XII) and formula (XIII) is (S).

[0059] In some embodiments of the IL-2 conjugates described herein, n in the compounds of formulas (XII) and (XIII) is in the range of about 5 to about 4600, or about 10 to about 4000, or about 20 to about 3000, or about 100 to about 3000, or about 100 to about 2900, or about 150 to about 2900, or about 125 to about 2900, or about 100 to about 2500, or about 100 to about 2000, or about 100 to about 1900, or about 100 to about 1850, or about 100 to about 1750, or about 100 to about 1650, or about 100 to about 1500, or about 100 to about 1400, or about 100 to about 1300, or about 100 to about 1250, or about 100 to about 1150, or about 100 to about 1100, or about 100 to about 1000, or about 100 to about 900, or about 100 to about 750, or about 100 to about 700, or about 100 to about 600, or about 100 to about 575, or about 100 to about 500, or about 100 to about 450, or about 100 to about 350, or about 100 to about 275, or about 100 to about 230, or about 150 to about 475, or about 150 to about 340, or about 113 to about 340, or about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 340 to about 795, or about 341 to about 682, or about 568 to about 909, or about 227 to about 1500, or about 225 to about 2280, or about 460 to about 2160, or about 460 to about 2050, or about 341 to about 1820, or about 341 to about 1710, or about 341 to about 1250, or about 225 to about 1250, or about 341 to about 1250, or about 341 to about 1136, or about 341 to about 1023, or about 341 to about 910, or about 341 to about 796, or about 341 to about 682, or about 341 to about 568, or about 114 to about 1000, or about 114 to about 950, or about 114 to about 910, or about 114 to about 800, or about 114 to about 690, or about 114 to about 575.In some embodiments of the IL-2 conjugates described herein, n in the compounds of formulas (XII) and (XIII) is an integer selected from 2, 5, 10, 11, 22, 23, 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, 1249, 1250, 1251, 1362, 1363, 1364, 1476, 1477, 1478, 1589, 1590, 1591, 1703, 1704, 1705, 1817, 1818, 1819, 1930, 1931, 1932, 2044, 2045, 2046, 2158, 2159, 2160, 2271, 2272, 2273, 2839, 2840, 2841, 2953, 2954, 2955, 3408, 3409, 3410, 3976, 3977, 3978, 4544, 4545, and 4546. In some embodiments of the IL-2 conjugates described herein, the positions of the structures of formulas (XII) and (XIII) or the mixture of formulas (XII) and (XIII) in the amino acid sequence of the IL-2 conjugate are selected from K34, F41, F43, K42, E61, P64, R37, T40, E67, Y44, V68, and L71, and the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is based on the position of SEQ ID NO: 3. In some embodiments of the IL-2 conjugates described herein, the positions of the structures of formulas (XII) and (XIII) or the mixture of formulas (XII) and (XIII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 are selected from K34, F41, F43, K42, E61, P64, R37, T40, E67, Y44, V68, and L71. In some embodiments of the IL-2 conjugates described herein, the positions of the structures of formulas (XII) and (XIII) or the mixture of formulas (XII) and (XIII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 are at the K34 position.In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XII) and (XIII) or a mixture of formula (XII) and (XIII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position F41. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XII) and (XIII) or a mixture of formula (XII) and (XIII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position F43. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XII) and (XIII) or a mixture of formula (XII) and (XIII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position K42. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XII) and (XIII) or a mixture of formula (XII) and (XIII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position E61. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XII) and (XIII) or a mixture of formula (XII) and (XIII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position P64. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XII) and (XIII) or a mixture of formula (XII) and (XIII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position R37. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XII) and (XIII) or a mixture of formula (XII) and (XIII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position T40. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XII) and (XIII) or a mixture of formula (XII) and (XIII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position E67.In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XII) and (XIII) or a mixture of formula (XII) and (XIII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position Y44. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XII) and (XIII) or a mixture of formula (XII) and (XIII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position V68. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XII) and (XIII) or a mixture of formula (XII) and (XIII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position L71. In some embodiments of the IL-2 conjugate described herein, the ratio of the amount of the structure of formula (XII) to the amount of the structure of formula (XIII), including the total amount of the IL-2 conjugate, is about 1:1. In some embodiments of the IL-2 conjugate described herein, the ratio of the amount of the structure of formula (XII) to the amount of the structure of formula (XIII), including the total amount of the IL-2 conjugate, is greater than 1:1. In some embodiments of the IL-2 conjugate described herein, the ratio of the amount of the structure of formula (XII) to the amount of the structure of formula (XIII), including the total amount of the IL-2 conjugate, is less than 1:1.

[0060] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), and the amino acid residues in SEQ ID NO:3 to be replaced are selected from K34, F41, F43, K42, E61, P64, R37, T40, E67, Y44, V68, and L71, and n is an integer from 100 to about 1150, or about 100 to about 1100, or about 100 to about 1000, or about 100 to about 900, or about 100 to about 750, or about 100 to about 700, or about 100 to about 600, or about 100 to about 575, or about 100 to about 500, or about 100 to about 450, or about 100 to about 350, or about 100 to about 275, or about 100 to about 230, or about 150 to about 475, or about 150 to about 340, or about 113 to about 340, or about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 340 to about 795, or about 341 to about 682, or about 568 to about 909, or about 227 to about 1500, or about 225 to about 2280, or about 460 to about 2160, or about 460 to about 2050, or about 341 to about 1820, or about 341 to about 1710, or about 341 to about 1250, or about 225 to about 1250, or about 341 to about 1250, or about 341 to about 1136, or about 341 to about 1023, or about 341 to about 910, or about 341 to about 796, or about 341 to about 682, or about 341 to about 568, or about 114 to about 1000, or about 114 to about 950, or about 114 to about 910, or about 114 to about 800, or about 114 to about 690, or about 114 to about 575.In some embodiments of the IL-2 conjugates described herein, n in the compounds of formulas (XII) and (XIII) is an integer selected from 2, 5, 10, 11, 22, 23, 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, 1249, 1250, 1251, 1362, 1363, 1364, 1476, 1477, 1478, 1589, 1590, 1591, 1703, 1704, 1705, 1817, 1818, 1819, 1930, 1931, 1932, 2044, 2045, 2046, 2158, 2159, 2160, 2271, 2272, 2273, 2839, 2840, 2841, 2953, 2954, 2955, 3408, 3409, 3410, 3976, 3977, 3978, 4544, 4545, and 4546.

[0061] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), the amino acid residue in SEQ ID NO: 3 to be replaced is selected from F41, F43, K42, E61, and P64, and n is an integer from about 450 to about 800, or from about 454 to about 796, or from about 454 to about 682, or from about 568 to about 909. In some embodiments of the IL-2 conjugates described herein, n in the compounds of formulas (XII) and (XIII) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, and 1249.

[0062] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), the amino acid residue in SEQ ID NO:3 to be replaced is selected from E61 and P64, and n is an integer from about 450 to about 800, or from about 454 to about 796, or from about 454 to about 682, or from about 568 to about 909. In some embodiments of the IL-2 conjugate described herein, n in the compounds of formula (XII) and (XIII) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910.

[0063] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), the amino acid residue in SEQ ID NO:3 to be replaced is E61, and n is an integer from about 450 to about 800, or from about 454 to about 796, or from about 454 to about 682, or from about 568 to about 909. In some embodiments of the IL-2 conjugate described herein, n in the compounds of formula (XII) and (XIII) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910. In some embodiments, n is from about 500 to about 1000. In some embodiments, n is from about 550 to about 800. In some embodiments, n is about 681.

[0064] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), the amino acid residue in SEQ ID NO:3 to be replaced is P64, and n is an integer from about 450 to about 800, or from about 454 to about 796, or from about 454 to about 682, or from about 568 to about 909. In some embodiments of the IL-2 conjugate described herein, n in the compounds of formula (XII) and (XIII) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910. In some embodiments, n is from about 500 to about 1000. In some embodiments, n is from about 550 to about 800. In some embodiments, n is about 681.

[0065] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), and n is such that the molecular weight of the PEG moiety is from about 1,000 Daltons to about 200,000 Daltons, or from about 2,000 Daltons to about 150,000 Daltons, or from about 3,000 Daltons to about 125,000 Daltons, or from about 4,000 Daltons to about 100,000 Daltons, or from about 5,000 Daltons to about 100,000 Daltons, or from about 6,000 Daltons to about 90,000 Daltons, or from about 7,000 Daltons to about 80,000 Daltons, or from about 8,000 Daltons to about 70,000 Daltons, or from about 5,000 Daltons to about 70,000 Daltons, or from about 5,000 Daltons to about 65,000 Daltons, or from about 5,000 Daltons to about 60,000 Daltons, or from about 5,000 Daltons to about 50,000 Daltons, or from about 6,000 Daltons to about 50,000 Daltons, or from about 7,000 Daltons to about 50,000 Daltons, or from about 7,000 Daltons to about 45,000 Daltons, or from about 7,000 Daltons to about 40,000 Daltons, or from about 8,000 Daltons to about 40,000 Daltons, or from about 8,500 Daltons to about 40,000 Daltons, or from about 8,500 Daltons to about 35,000 Daltons, or from about 9,000 Daltons to about 50,000 Daltons, or from about 9,000 Daltons to about 45,000 Daltons, or from about 9,000 Daltons to about 40,000 Daltons, or from about 9,000 Daltons to about 35,000 Daltons, or from about 9,000 Daltons to about 30,000 Daltons, or from about 9,500 Daltons to about 35,000 Daltons, or from about 9,500 Daltons to about 30,000 Daltons, or from about 10,000 Daltons to about 50,000 Daltons, or from about 10,000 Daltons to about 45,000 Daltons, or from about 10,000 Daltons to about 40,000 Daltons, or from about 10,000 Daltons to about 35,000 Daltons, or from about 10,000 Daltons to about 30,000 Daltons, or from about 15,000 Daltons to about 50,000 Daltons, or from about 15,000 Daltons to about 45,An integer in the range of 000 Daltons, or from about 15,000 Daltons to about 40,000 Daltons, or from about 15,000 Daltons to about 35,000 Daltons, or from about 15,000 Daltons to about 30,000 Daltons, or from about 20,000 Daltons to about 50,000 Daltons, or from about 20,000 Daltons to about 45,000 Daltons, or from about 20,000 Daltons to about 40,000 Daltons, or from about 20,000 Daltons to about 35,000 Daltons, or from about 20,000 Daltons to about 30,000 Daltons. Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), and n is an integer such that the molecular weight of the PEG moiety is about 5,000 Daltons, about 7,500 Daltons, about 10,000 Daltons, about 15,000 Daltons, about 20,000 Daltons, about 25,000 Daltons, about 30,000 Daltons, about 35,000 Daltons, about 40,000 Daltons, about 45,000 Daltons, about 50,000 Daltons, about 60,000 Daltons, about 70,000 Daltons, about 80,000 Daltons, about 90,000 Daltons, about 100,000 Daltons, about 125,000 Daltons, about 150,000 Daltons, about 175,000 Daltons or about 200,000 Daltons. Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XII) or (XIII), or a mixture of (XII) and (XIII), and n is an integer such that the molecular weight of the PEG moiety is about 5,000 Daltons, about 7,500 Daltons, about 10,000 Daltons, about 15,000 Daltons, about 20,000 Daltons, about 25,000 Daltons, about 30,000 Daltons, about 35,000 Daltons, about 40,000 Daltons, about 45,000 Daltons, or about 50,000 Daltons.,

[0066] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV): [Chemical formula] (Wherein: m is an integer from 0 to 20; p is an integer from 0 to 20; n is an integer in the range of about 2 to about 5000; The wavy line indicates a covalent bond to the amino acid residue in SEQ ID NO:3 that has not been replaced), or a pharmaceutically acceptable salt, solvate, or hydrate thereof.

[0067] In some embodiments, the stereochemistry of the chiral centers in formula (XIV) and formula (XV) is racemic, rich in (R), rich in (S), substantially (R), substantially (S), (R), or (S). In some embodiments, the stereochemistry of the chiral centers in formula (XIV) and formula (XV) is racemic. In some embodiments, the stereochemistry of the chiral centers in formula (XIV) and formula (XV) is rich in (R). In some embodiments, the stereochemistry of the chiral centers in formula (XIV) and formula (XV) is rich in (S). In some embodiments, the stereochemistry of the chiral centers in formula (XIV) and formula (XV) is substantially (R). In some embodiments, the stereochemistry of the chiral centers in formula (XIV) and formula (XV) is substantially (S). In some embodiments, the stereochemistry of the chiral centers in formula (XIV) and formula (XV) is (R). In some embodiments, the stereochemistry of the chiral centers in formula (XIV) and formula (XV) is (S).

[0068] In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XIV) and (XV) is 0 to 20, or 0 to 18, or 0 to 16, or 0 to 14, or 0 to 12, or 0 to 10, or 0 to 9, or 0 to 8, or 0 to 7, or 0 to 6, or 0 to 5, or 0 to 4, or 0 to 3, or 0 to 2. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XIV) and (XV) is 0. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XIV) and (XV) is 1. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XIV) and (XV) is 2. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XIV) and (XV) is 3. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XIV) and (XV) is 4. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XIV) and (XV) is 5. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XIV) and (XV) is 6. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XIV) and (XV) is 7. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XIV) and (XV) is 8. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XIV) and (XV) is 9. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XIV) and (XV) is 10. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XIV) and (XV) is 11. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XIV) and (XV) is 12.In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XIV) and (XV) is 13. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XIV) and (XV) is 14. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XIV) and (XV) is 15. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XIV) and (XV) is 16. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XIV) and (XV) is 17. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XIV) and (XV) is 18. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XIV) and (XV) is 19. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XIV) and (XV) is 20.

[0069] In some embodiments of the IL-2 conjugates described herein, p in the compounds of formulas (XIV) and (XV) is from 0 to 20, or from 0 to 18, or from 0 to 16, or from 0 to 14, or from 0 to 12, or from 0 to 10, or from 0 to 9, or from 0 to 8, or from 0 to 7, or from 0 to 6, or from 0 to 5, or from 0 to 4, or from 0 to 3, or from 0 to 2. In some embodiments of the IL-2 conjugates described herein, p in the compounds of formulas (XIV) and (XV) is 0. In some embodiments of the IL-2 conjugates described herein, p in the compounds of formulas (XIV) and (XV) is 1. In some embodiments of the IL-2 conjugates described herein, p in the compounds of formulas (XIV) and (XV) is 2. In some embodiments of the IL-2 conjugates described herein, p in the compounds of formulas (XIV) and (XV) is 3. In some embodiments of the IL-2 conjugates described herein, p in the compounds of formulas (XIV) and (XV) is 4. In some embodiments of the IL-2 conjugates described herein, p in the compounds of formulas (XIV) and (XV) is 5. In some embodiments of the IL-2 conjugates described herein, p in the compounds of formulas (XIV) and (XV) is 6. In some embodiments of the IL-2 conjugates described herein, p in the compounds of formulas (XIV) and (XV) is 7. In some embodiments of the IL-2 conjugates described herein, p in the compounds of formulas (XIV) and (XV) is 8. In some embodiments of the IL-2 conjugates described herein, p in the compounds of formulas (XIV) and (XV) is 9. In some embodiments of the IL-2 conjugates described herein, p in the compounds of formulas (XIV) and (XV) is 10. In some embodiments of the IL-2 conjugates described herein, p in the compounds of formulas (XIV) and (XV) is 11. In some embodiments of the IL-2 conjugates described herein, p in the compounds of formulas (XIV) and (XV) is 12.In some embodiments of the IL-2 conjugates described herein, p in the compounds of formulas (XIV) and (XV) is 13. In some embodiments of the IL-2 conjugates described herein, p in the compounds of formulas (XIV) and (XV) is 14. In some embodiments of the IL-2 conjugates described herein, p in the compounds of formulas (XIV) and (XV) is 15. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XIV) and (XV) is 16. In some embodiments of the IL-2 conjugates described herein, p in the compounds of formulas (XIV) and (XV) is 17. In some embodiments of the IL-2 conjugates described herein, p in the compounds of formulas (XIV) and (XV) is 18. In some embodiments of the IL-2 conjugates described herein, p in the compounds of formulas (XIV) and (XV) is 19. In some embodiments of the IL-2 conjugates described herein, p in the compounds of formulas (XIV) and (XV) is 20.

[0070] In some embodiments of the IL-2 conjugates described herein, n in the compounds of formula (XIV) and (XV) is in the range of about 5 to about 4600, or about 10 to about 4000, or about 20 to about 3000, or about 100 to about 3000, or about 100 to about 2900, or about 150 to about 2900, or about 125 to about 2900, or about 100 to about 2500, or about 100 to about 2000, or about 100 to about 1900, or about 100 to about 1850, or about 100 to about 1750, or about 100 to about 1650, or about 100 to about 1500, or about 100 to about 1400, or about 100 to about 1300, or about 100 to about 1250, or about 100 to about 1150, or about 100 to about 1100, or about 100 to about 1000, or about 100 to about 900, or about 100 to about 750, or about 100 to about 700, or about 100 to about 600, or about 100 to about 575, or about 100 to about 500, or about 100 to about 450, or about 100 to about 350, or about 100 to about 275, or about 100 to about 230, or about 150 to about 475, or about 150 to about 340, or about 113 to about 340, or about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 340 to about 795, or about 341 to about 682, or about 568 to about 909, or about 227 to about 1500, or about 225 to about 2280, or about 460 to about 2160, or about 460 to about 2050, or about 341 to about 1820, or about 341 to about 1710, or about 341 to about 1250, or about 225 to about 1250, or about 341 to about 1250, or about 341 to about 1136, or about 341 to about 1023, or about 341 to about 910, or about 341 to about 796, or about 341 to about 682, or about 341 to about 568, or about 114 to about 1000, or about 114 to about 950, or about 114 to about 910, or about 114 to about 800, or about 114 to about 690, or about 114 to about 575.

[0071] In some embodiments of the IL-2 conjugates described herein, in the compounds of formulas (XIV) and (XV), m is an integer from 0 to 6, p is an integer from 0 to 6, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formulas (XIV) and (XV), m is an integer from 1 to 6, p is an integer from 1 to 6, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formulas (XIV) and (XV), m is an integer from 2 to 6, p is an integer from 2 to 6, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formulas (XIV) and (XV), m is an integer from 2 to 4, p is an integer from 2 to 4, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formulas (XIV) and (XV), m is 1, p is 2, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137.In some embodiments of the IL-2 conjugates described herein, in the compounds of formulas (XIV) and (XV), m is 2, p is 2, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formulas (XIV) and (XV), m is 3, p is 2, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formulas (XIV) and (XV), m is 4, p is 2, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formulas (XIV) and (XV), m is 5, p is 2, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formulas (XIV) and (XV), m is 6, p is 2, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137.In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XIV) and (XV), m is 7, p is 2, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XIV) and (XV), m is 8, p is 2, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XIV) and (XV), m is 9, p is 2, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XIV) and (XV), m is 10, p is 2, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XIV) and (XV), m is 11, p is 2, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137.In some embodiments of the IL-2 conjugates described herein, in the compounds of formulas (XIV) and (XV), m is 11, p is 2, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formulas (XIV) and (XV), m is 2, p is 2, and n is an integer selected from 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137.

[0072] In some embodiments of the IL-2 conjugates described herein, n in the compounds of formulas (XIV) and (XV) is an integer selected from 2, 5, 10, 11, 22, 23, 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, 1249, 1250, 1251, 1362, 1363, 1364, 1476, 1477, 1478, 1589, 1590, 1591, 1703, 1704, 1705, 1817, 1818, 1819, 1930, 1931, 1932, 2044, 2045, 2046, 2158, 2159, 2160, 2271, 2272, 2273, 2839, 2840, 2841, 2953, 2954, 2955, 3408, 3409, 3410, 3976, 3977, 3978, 4544, 4545, and 4546. In some embodiments of the IL-2 conjugates described herein, the positions of the structures of formulas (XIV) and (XV), or a mixture of formulas (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate are selected from K34, F41, F43, K42, E61, P64, R37, T40, E67, Y44, V68, and L71, and the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is based on the position of SEQ ID NO: 3. In some embodiments of the IL-2 conjugates described herein, the positions of the structures of formulas (XIV) and (XV), or a mixture of formulas (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 are selected from K34, F41, F43, K42, E61, P64, R37, T40, E67, Y44, V68, and L71. In some embodiments of the IL-2 conjugates described herein, the positions of the structures of formulas (XIV) and (XV), or a mixture of formulas (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 are at the K34 position.In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XIV) and (XV), or a mixture of formula (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position F41. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XIV) and (XV), or a mixture of formula (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position F43. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XIV) and (XV), or a mixture of formula (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position K42. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XIV) and (XV), or a mixture of formula (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position E61. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XIV) and (XV), or a mixture of formula (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position P64. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XIV) and (XV), or a mixture of formula (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position R37. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XIV) and (XV), or a mixture of formula (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position T40. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XIV) and (XV), or a mixture of formula (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position E67. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XIV) and (XV), or a mixture of formula (XIV) and (XV), in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position Y44.In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XIV) and (XV), or a mixture of formula (XIV) and (XV) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position V68. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XIV) and (XV), or a mixture of formula (XIV) and (XV) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position L71. In some embodiments of the IL-2 conjugate described herein, the ratio of the amount of the structure of formula (XIV) to the amount of the structure of formula (XV), including the total amount of the IL-2 conjugate, is about 1:1. In some embodiments of the IL-2 conjugate described herein, the ratio of the amount of the structure of formula (XIV) to the amount of the structure of formula (XV), including the total amount of the IL-2 conjugate, is greater than 1:1. In some embodiments of the IL-2 conjugate described herein, the ratio of the amount of the structure of formula (XIV) to the amount of the structure of formula (XV), including the total amount of the IL-2 conjugate, is less than 1:1.

[0073] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), and the amino acid residue in SEQ ID NO:3 to be replaced is selected from K34, F41, F43, K42, E61, P64, R37, T40, E67, Y44, V68, and L71, and n is an integer of 100 to about 1150, or about 100 to about 1100, or about 100 to about 1000, or about 100 to about 900, or about 100 to about 750, or about 100 to about 700, or about 100 to about 600, or about 100 to about 575, or about 100 to about 500, or about 100 to about 450, or about 100 to about 350, or about 100 to about 275, or about 100 to about 230, or about 150 to about 475, or about 150 to about 340, or about 113 to about 340, or about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 340 to about 795, or about 341 to about 682, or about 568 to about 909, or about 227 to about 1500, or about 225 to about 2280, or about 460 to about 2160, or about 460 to about 2050, or about 341 to about 1820, or about 341 to about 1710, or about 341 to about 1250, or about 225 to about 1250, or about 341 to about 1250, or about 341 to about 1136, or about 341 to about 1023, or about 341 to about 910, or about 341 to about 796, or about 341 to about 682, or about 341 to about 568, or about 114 to about 1000, or about 114 to about 950, or about 114 to about 910, or about 114 to about 800, or about 114 to about 690, or about 114 to about 575.In some embodiments of the IL-2 conjugates described herein, n in the compounds of formula (XIV) and (XV) is an integer selected from 2, 5, 10, 11, 22, 23, 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, 1249, 1250, 1251, 1362, 1363, 1364, 1476, 1477, 1478, 1589, 1590, 1591, 1703, 1704, 1705, 1817, 1818, 1819, 1930, 1931, 1932, 2044, 2045, 2046, 2158, 2159, 2160, 2271, 2272, 2273, 2839, 2840, 2841, 2953, 2954, 2955, 3408, 3409, 3410, 3976, 3977, 3978, 4544, 4545, and 4546.

[0074] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), the amino acid residue in SEQ ID NO:3 to be replaced is selected from F41, F43, K42, E61, and P64, and n is an integer of about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 568 to about 909. In some embodiments of the IL-2 conjugates described herein, n in the compounds of formula (XIV) and (XV) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, and 1249.

[0075] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), the amino acid residue in SEQ ID NO:3 to be replaced is selected from E61 and P64, and n is an integer from about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 568 to about 909. In some embodiments of the IL-2 conjugate described herein, n in the compounds of formula (XIV) and (XV) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910.

[0076] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), the amino acid residue in SEQ ID NO:3 to be replaced is E61, and n is an integer from about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 568 to about 909. In some embodiments of the IL-2 conjugate described herein, n in the compounds of formula (XIV) and (XV) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910. In some embodiments, n is from about 500 to about 1000. In some embodiments, n is from about 550 to about 800. In some embodiments, n is about 681.

[0077] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), the amino acid residue in SEQ ID NO:3 to be replaced is P64, and n is an integer from about 450 to about 800, or from about 454 to about 796, or from about 454 to about 682, or from about 568 to about 909. In some embodiments of the IL-2 conjugates described herein, n in the compounds of formula (XIV) and (XV) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910. In some embodiments, n is from about 500 to about 1000. In some embodiments, n is from about 550 to about 800. In some embodiments, n is about 681.

[0078] Disclosed herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), and n is such that the molecular weight of the PEG moiety is from about 1,000 Daltons to about 200,000 Daltons, or from about 2,000 Daltons to about 150,000 Daltons, or from about 3,000 Daltons to about 125,000 Daltons, or from about 4,000 Daltons to about 100,000 Daltons, or from about 5,000 Daltons to about 100,000 Daltons, or from about 6,000 Daltons to about 90,000 Daltons, or from about 7,000 Daltons to about 80,000 Daltons, or from about 8,000 Daltons to about 70,000 Daltons, or from about 5,000 Daltons to about 70,000 Daltons, or from about 5,000 Daltons to about 65,000 Daltons, or from about 5,000 Daltons to about 60,000 Daltons, or from about 5,000 Daltons to about 50,000 Daltons, or from about 6,000 Daltons to about 50,000 Daltons, or from about 7,000 Daltons to about 50,000 Daltons, or from about 7,000 Daltons to about 45,000 Daltons, or from about 7,000 Daltons to about 40,000 Daltons, or from about 8,000 Daltons to about 40,000 Daltons, or from about 8,500 Daltons to about 40,000 Daltons, or from about 8,500 Daltons to about 35,000 Daltons, or from about 9,000 Daltons to about 50,000 Daltons, or from about 9,000 Daltons to about 45,000 Daltons, or from about 9,000 Daltons to about 40,000 Daltons, or from about 9,000 Daltons to about 35,000 Daltons, or from about 9,000 Daltons to about 30,000 Daltons, or from about 9,500 Daltons to about 35,000 Daltons, or from about 9,500 Daltons to about 30,000 Daltons, or from about 10,000 Daltons to about 50,000 Daltons, or from about 10,000 Daltons to about 45,000 Daltons, or from about 10,000 Daltons to about 40,000 Daltons, or from about 10,000 Daltons to about 35,000 Daltons, or from about 10,000 Daltons to about 30,000 Daltons, or from about 15,000 Daltons to about 50,000 Daltons, or from about 15,000 Daltons to about 45,An integer in the range of 000 Daltons, or about 15,000 Daltons to about 40,000 Daltons, or about 15,000 Daltons to about 35,000 Daltons, or about 15,000 Daltons to about 30,000 Daltons, or about 20,000 Daltons to about 50,000 Daltons, or about 20,000 Daltons to about 45,000 Daltons, or about 20,000 Daltons to about 40,000 Daltons, or about 20,000 Daltons to about 35,000 Daltons, or about 20,000 Daltons to about 30,000 Daltons. Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), and n is an integer such that the molecular weight of the PEG moiety is about 5,000 Daltons, about 7,500 Daltons, about 10,000 Daltons, about 15,000 Daltons, about 20,000 Daltons, about 25,000 Daltons, about 30,000 Daltons, about 35,000 Daltons, about 40,000 Daltons, about 45,000 Daltons, about 50,000 Daltons, about 60,000 Daltons, about 70,000 Daltons, about 80,000 Daltons, about 90,000 Daltons, about 100,000 Daltons, about 125,000 Daltons, about 150,000 Daltons, about 175,000 Daltons or about 200,000 Daltons. Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), and n is an integer such that the molecular weight of the PEG moiety is about 5,000 Daltons, about 7,500 Daltons, about 10,000 Daltons, about 15,000 Daltons, about 20,000 Daltons, about 25,000 Daltons, about 30,000 Daltons, about 35,000 Daltons, about 40,000 Daltons, about 45,000 Daltons, or about 50,000 Daltons.,

[0079] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), the amino acid residues in SEQ ID NO: 3 to be replaced are selected from F41, F43, K42, E61, and P64, m is an integer from 0 to 6, p is an integer from 0 to 6, and n is an integer of about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 568 to about 909. In some embodiments of the IL-2 conjugate described herein, in the compounds of formula (XIV) and (XV), m is 2, p is 2, and n is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, and 1249.

[0080] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), the amino acid residues in SEQ ID NO: 3 to be replaced are selected from E61 and P64, m is an integer from 0 to 6, p is an integer from 0 to 6, and n is an integer of about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 568 to about 909. In some embodiments of the IL-2 conjugate described herein, in the compounds of formula (XIV) and (XV), m is 2, p is 2, and n is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910.

[0081] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), the amino acid residue in SEQ ID NO: 3 to be replaced is E61, m is an integer from 0 to 6, p is an integer from 0 to 6, and n is an integer from about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 568 to about 909. In some embodiments of the IL-2 conjugate described herein, in the compounds of formula (XIV) and (XV), m is 2, p is 2, and n is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910. In some embodiments, n is from about 500 to about 1000. In some embodiments, n is from about 550 to about 800. In some embodiments, n is about 681.

[0082] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XIV) or (XV), or a mixture of (XIV) and (XV), the amino acid residue in SEQ ID NO: 3 to be replaced is P64, m is an integer from 0 to 6, p is an integer from 0 to 6, and n is an integer from about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 568 to about 909. In some embodiments of the IL-2 conjugate described herein, in the compounds of formula (XIV) and (XV), m is 2, p is 2, and n is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910. In some embodiments, n is from about 500 to about 1000. In some embodiments, n is from about 550 to about 800. In some embodiments, n is about 681.

[0083] Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate has the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII): [Chemical Formula] (Wherein: m is an integer from 0 to 20; n is an integer in the range of about 2 to about 5000; The wavy line indicates a covalent bond to the amino acid residue in SEQ ID NO:3 that has not been replaced) an IL-2 conjugate, or a pharmaceutically acceptable salt, solvate, or hydrate thereof.

[0084] In some embodiments, the stereochemistry of the chiral centers in formula (XVI) and formula (XVII) is racemic, rich in (R), rich in (S), substantially (R), substantially (S), (R), or (S). In some embodiments, the stereochemistry of the chiral centers in formula (XVI) and formula (XVII) is racemic. In some embodiments, the stereochemistry of the chiral centers in formula (XVI) and formula (XVII) is rich in (R). In some embodiments, the stereochemistry of the chiral centers in formula (XVI) and formula (XVII) is rich in (S). In some embodiments, the stereochemistry of the chiral centers in formula (XVI) and formula (XVII) is substantially (R). In some embodiments, the stereochemistry of the chiral centers in formula (XVI) and formula (XVII) is substantially (S). In some embodiments, the stereochemistry of the chiral centers in formula (XVI) and formula (XVII) is (R). In some embodiments, the stereochemistry of the chiral centers in formula (XVI) and formula (XVII) is (S).

[0085] In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XVI) and (XVII) is 0 to 20, or 0 to 18, or 0 to 16, or 0 to 14, or 0 to 12, or 0 to 10, or 0 to 9, or 0 to 8, or 0 to 7, or 0 to 6, or 0 to 5, or 0 to 4, or 0 to 3, or 0 to 2. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XVI) and (XVII) is 0. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XVI) and (XVII) is 1. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XVI) and (XVII) is 2. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XVI) and (XVII) is 3. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XVI) and (XVII) is 4. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XVI) and (XVII) is 5. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XVI) and (XVII) is 6. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XVI) and (XVII) is 7. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XVI) and (XVII) is 8. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XVI) and (XVII) is 9. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XVI) and (XVII) is 10. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XVI) and (XVII) is 11. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XVI) and (XVII) is 12.In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XVI) and (XVII) is 13. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XVI) and (XVII) is 14. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XVI) and (XVII) is 15. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XVI) and (XVII) is 16. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XVI) and (XVII) is 17. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XVI) and (XVII) is 18. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XVI) and (XVII) is 19. In some embodiments of the IL-2 conjugates described herein, m in the compounds of formulas (XVI) and (XVII) is 20.

[0086] In some embodiments of the IL-2 conjugates described herein, n in the compounds of formula (XVI) and (XVII) is in the range of about 5 to about 4600, or about 10 to about 4000, or about 20 to about 3000, or about 100 to about 3000, or about 100 to about 2900, or about 150 to about 2900, or about 125 to about 2900, or about 100 to about 2500, or about 100 to about 2000, or about 100 to about 1900, or about 100 to about 1850, or about 100 to about 1750, or about 100 to about 1650, or about 100 to about 1500, or about 100 to about 1400, or about 100 to about 1300, or about 100 to about 1250, or about 100 to about 1150, or about 100 to about 1100, or about 100 to about 1000, or about 100 to about 900, or about 100 to about 750, or about 100 to about 700, or about 100 to about 600, or about 100 to about 575, or about 100 to about 500, or about 100 to about 450, or about 100 to about 350, or about 100 to about 275, or about 100 to about 230, or about 150 to about 475, or about 150 to about 340, or about 113 to about 340, or about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 340 to about 795, or about 341 to about 682, or about 568 to about 909, or about 227 to about 1500, or about 225 to about 2280, or about 460 to about 2160, or about 460 to about 2050, or about 341 to about 1820, or about 341 to about 1710, or about 341 to about 1250, or about 225 to about 1250, or about 341 to about 1250, or about 341 to about 1136, or about 341 to about 1023, or about 341 to about 910, or about 341 to about 796, or about 341 to about 682, or about 341 to about 568, or about 114 to about 1000, or about 114 to about 950, or about 114 to about 910, or about 114 to about 800, or about 114 to about 690, or about 114 to about 575.

[0087] In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XVI) and (XVII), m is an integer from 0 to 6, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XVI) and (XVII), m is an integer from 1 to 6, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XVI) and (XVII), m is an integer from 2 to 6, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XVI) and (XVII), m is an integer from 2 to 4, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formula (XVI) and (XVII), m is 1, and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137.In some embodiments of the IL-2 conjugates described herein, in the compounds of formulas (XVI) and (XVII), m is 2 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formulas (XVI) and (XVII), m is 3 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formulas (XVI) and (XVII), m is 4 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formulas (XVI) and (XVII), m is 5 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formulas (XVI) and (XVII), m is 6 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137.In some embodiments of the IL-2 conjugates described herein, in the compounds of formulas (XVI) and (XVII), m is 7 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formulas (XVI) and (XVII), m is 8 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formulas (XVI) and (XVII), m is 9 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formulas (XVI) and (XVII), m is 10 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formulas (XVI) and (XVII), m is 11 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137.In some embodiments of the IL-2 conjugates described herein, in the compounds of formulas (XVI) and (XVII), m is 12 and n is an integer selected from 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137. In some embodiments of the IL-2 conjugates described herein, in the compounds of formulas (XVI) and (XVII), m is 2 and n is an integer selected from 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, and 1137.

[0088] In some embodiments of the IL-2 conjugates described herein, n in the compounds of formulas (XVI) and (XVII) is an integer selected from 2, 5, 10, 11, 22, 23, 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, 1249, 1250, 1251, 1362, 1363, 1364, 1476, 1477, 1478, 1589, 1590, 1591, 1703, 1704, 1705, 1817, 1818, 1819, 1930, 1931, 1932, 2044, 2045, 2046, 2158, 2159, 2160, 2271, 2272, 2273, 2839, 2840, 2841, 2953, 2954, 2955, 3408, 3409, 3410, 3976, 3977, 3978, 4544, 4545, and 4546. In some embodiments of the IL-2 conjugates described herein, the positions of the structures of formulas (XVI) and (XVII) or a mixture of formulas (XVI) and (XVII) in the amino acid sequence of the IL-2 conjugate are selected from K34, F41, F43, K42, E61, P64, R37, T40, E67, Y44, V68, and L71, and the position of the structure of formula (I) in the amino acid sequence of the IL-2 conjugate is based on the position of SEQ ID NO: 3. In some embodiments of the IL-2 conjugates described herein, the positions of the structures of formulas (XVI) and (XVII) or a mixture of formulas (XVI) and (XVII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 are selected from K34, F41, F43, K42, E61, P64, R37, T40, E67, Y44, V68, and L71. In some embodiments of the IL-2 conjugates described herein, the positions of the structures of formulas (XVI) and (XVII) or a mixture of formulas (XVI) and (XVII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 are at the K34 position.In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XVI) and (XVII) or a mixture of formula (XVI) and (XVII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position F41. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XVI) and (XVII) or a mixture of formula (XVI) and (XVII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position F43. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XVI) and (XVII) or a mixture of formula (XVI) and (XVII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position K42. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XVI) and (XVII) or a mixture of formula (XVI) and (XVII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position E61. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XVI) and (XVII) or a mixture of formula (XVI) and (XVII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position P64. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XVI) and (XVII) or a mixture of formula (XVI) and (XVII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position R37. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XVI) and (XVII) or a mixture of formula (XVI) and (XVII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position T40. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XVI) and (XVII) or a mixture of formula (XVI) and (XVII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is position E67.In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XVI) and (XVII) or a mixture of formula (XVI) and (XVII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is at position Y44. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XVI) and (XVII) or a mixture of formula (XVI) and (XVII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is at position V68. In some embodiments of the IL-2 conjugate described herein, the position of the structure of formula (XVI) and (XVII) or a mixture of formula (XVI) and (XVII) in the amino acid sequence of the IL-2 conjugate of SEQ ID NO: 3 is at position L71. In some embodiments of the IL-2 conjugate described herein, the ratio of the amount of the structure of formula (XVI) to the amount of the structure of formula (XVII), including the total amount of the IL-2 conjugate, is about 1:1. In some embodiments of the IL-2 conjugate described herein, the ratio of the amount of the structure of formula (XVI) to the amount of the structure of formula (XVII), including the total amount of the IL-2 conjugate, is greater than 1:1. In some embodiments of the IL-2 conjugate described herein, the ratio of the amount of the structure of formula (XVI) to the amount of the structure of formula (XVII), including the total amount of the IL-2 conjugate, is less than 1:1.

[0089] In one embodiment, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), and the amino acid residues in SEQ ID NO:3 to be replaced are selected from K34, F41, F43, K42, E61, P64, R37, T40, E67, Y44, V68, and L71, and n is an integer from 100 to about 1150, or about 100 to about 1100, or about 100 to about 1000, or about 100 to about 900, or about 100 to about 750, or about 100 to about 700, or about 100 to about 600, or about 100 to about 575, or about 100 to about 500, or about 100 to about 450, or about 100 to about 350, or about 100 to about 275, or about 100 to about 230, or about 150 to about 475, or about 150 to about 340, or about 113 to about 340, or about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 340 to about 795, or about 341 to about 682, or about 568 to about 909, or about 227 to about 1500, or about 225 to about 2280, or about 460 to about 2160, or about 460 to about 2050, or about 341 to about 1820, or about 341 to about 1710, or about 341 to about 1250, or about 225 to about 1250, or about 341 to about 1250, or about 341 to about 1136, or about 341 to about 1023, or about 341 to about 910, or about 341 to about 796, or about 341 to about 682, or about 341 to about 568, or about 114 to about 1000, or about 114 to about 950, or about 114 to about 910, or about 114 to about 800, or about 114 to about 690, or about 114 to about 575.In some embodiments of the IL-2 conjugates described herein, n in the compounds of formula (XVI) and (XVII) is an integer selected from 2, 5, 10, 11, 22, 23, 113, 114, 227, 228, 340, 341, 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, 1249, 1250, 1251, 1362, 1363, 1364, 1476, 1477, 1478, 1589, 1590, 1591, 1703, 1704, 1705, 1817, 1818, 1819, 1930, 1931, 1932, 2044, 2045, 2046, 2158, 2159, 2160, 2271, 2272, 2273, 2839, 2840, 2841, 2953, 2954, 2955, 3408, 3409, 3410, 3976, 3977, 3978, 4544, 4545, and 4546.

[0090] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), and the amino acid residue in SEQ ID NO: 3 to be replaced is selected from F41, F43, K42, E61, and P64, and n is an integer from about 450 to about 800, or from about 454 to about 796, or from about 454 to about 682, or from about 568 to about 909. In some embodiments of the IL-2 conjugates described herein, n in the compounds of formula (XVI) and (XVII) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, and 1249.

[0091] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), the amino acid residue in SEQ ID NO:3 to be replaced is selected from E61 and P64, and n is an integer from about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 568 to about 909. In some embodiments of the IL-2 conjugate described herein, n in the compounds of formula (XVI) and (XVII) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910.

[0092] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), the amino acid residue in SEQ ID NO:3 to be replaced is E61, and n is an integer from about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 568 to about 909. In some embodiments of the IL-2 conjugate described herein, n in the compounds of formula (XVI) and (XVII) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910. In some embodiments, n is from about 500 to about 1000. In some embodiments, n is from about 550 to about 800. In some embodiments, n is about 681.

[0093] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), the amino acid residue in SEQ ID NO:3 to be replaced is P64, and n is an integer from about 450 to about 800, or from about 454 to about 796, or from about 454 to about 682, or from about 568 to about 909. In some embodiments of the IL-2 conjugates described herein, n in the compounds of formula (XVI) and (XVII) is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910. In some embodiments, n is from about 500 to about 1000. In some embodiments, n is from about 550 to about 800. In some embodiments, n is about 681.

[0094] Disclosed herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), and n is such that the molecular weight of the PEG moiety is from about 1,000 Daltons to about 200,000 Daltons, or from about 2,000 Daltons to about 150,000 Daltons, or from about 3,000 Daltons to about 125,000 Daltons, or from about 4,000 Daltons to about 100,000 Daltons, or from about 5,000 Daltons to about 100,000 Daltons, or from about 6,000 Daltons to about 90,000 Daltons, or from about 7,000 Daltons to about 80,000 Daltons, or from about 8,000 Daltons to about 70,000 Daltons, or from about 5,000 Daltons to about 70,000 Daltons, or from about 5,000 Daltons to about 65,000 Daltons, or from about 5,000 Daltons to about 60,000 Daltons, or from about 5,000 Daltons to about 50,000 Daltons, or from about 6,000 Daltons to about 50,000 Daltons, or from about 7,000 Daltons to about 50,000 Daltons, or from about 7,000 Daltons to about 45,000 Daltons, or from about 7,000 Daltons to about 40,000 Daltons, or from about 8,000 Daltons to about 40,000 Daltons, or from about 8,500 Daltons to about 40,000 Daltons, or from about 8,500 Daltons to about 35,000 Daltons, or from about 9,000 Daltons to about 50,000 Daltons, or from about 9,000 Daltons to about 45,000 Daltons, or from about 9,000 Daltons to about 40,000 Daltons, or from about 9,000 Daltons to about 35,000 Daltons, or from about 9,000 Daltons to about 30,000 Daltons, or from about 9,500 Daltons to about 35,000 Daltons, or from about 9,500 Daltons to about 30,000 Daltons, or from about 10,000 Daltons to about 50,000 Daltons, or from about 10,000 Daltons to about 45,000 Daltons, or from about 10,000 Daltons to about 40,000 Daltons, or from about 10,000 Daltons to about 35,000 Daltons, or from about 10,000 Daltons to about 30,000 Daltons, or from about 15,000 Daltons to about 50,000 Daltons, or from about 15,000 Daltons to about 45,An integer in the range of 000 Daltons, or about 15,000 Daltons to about 40,000 Daltons, or about 15,000 Daltons to about 35,000 Daltons, or about 15,000 Daltons to about 30,000 Daltons, or about 20,000 Daltons to about 50,000 Daltons, or about 20,000 Daltons to about 45,000 Daltons, or about 20,000 Daltons to about 40,000 Daltons, or about 20,000 Daltons to about 35,000 Daltons, or about 20,000 Daltons to about 30,000 Daltons. Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), and n is an integer such that the molecular weight of the PEG moiety is about 5,000 Daltons, about 7,500 Daltons, about 10,000 Daltons, about 15,000 Daltons, about 20,000 Daltons, about 25,000 Daltons, about 30,000 Daltons, about 35,000 Daltons, about 40,000 Daltons, about 45,000 Daltons, about 50,000 Daltons, about 60,000 Daltons, about 70,000 Daltons, about 80,000 Daltons, about 90,000 Daltons, about 100,000 Daltons, about 125,000 Daltons, about 150,000 Daltons, about 175,000 Daltons or about 200,000 Daltons. Described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), and n is an integer such that the molecular weight of the PEG moiety is about 5,000 Daltons, about 7,500 Daltons, about 10,000 Daltons, about 15,000 Daltons, about 20,000 Daltons, about 25,000 Daltons, about 30,000 Daltons, about 35,000 Daltons, about 40,000 Daltons, about 45,000 Daltons, or about 50,000 Daltons.,

[0095] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), and the amino acid residues in SEQ ID NO: 3 to be replaced are selected from F41, F43, K42, E61, and P64, m is an integer from 0 to 6, and n is an integer of about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 568 to about 909. In some embodiments of the IL-2 conjugate described herein, in the compounds of formula (XVI) and (XVII), m is 2 and n is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, 910, 1021, 1022, 1023, 1135, 1136, 1137, and 1249.

[0096] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), and the amino acid residues in SEQ ID NO: 3 to be replaced are selected from E61 and P64, m is an integer from 0 to 6, and n is an integer of about 450 to about 800, or about 454 to about 796, or about 454 to about 682, or about 568 to about 909. In some embodiments of the IL-2 conjugate described herein, in the compounds of formula (XVI) and (XVII), m is 2 and n is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910.

[0097] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), the amino acid residue in SEQ ID NO:3 to be replaced is E61, m is an integer from 0 to 6, and n is an integer from about 450 to about 800, or from about 454 to about 796, or from about 454 to about 682, or from about 568 to about 909. In some embodiments of the IL-2 conjugate described herein, in the compounds of formula (XVI) and (XVII), m is 2 and n is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910. In some embodiments, n is from about 500 to about 1000. In some embodiments, n is from about 550 to about 800. In some embodiments, n is about 681.

[0098] In some embodiments, described herein is an IL-2 conjugate comprising the amino acid sequence of SEQ ID NO:3, wherein at least one amino acid residue in the IL-2 conjugate is replaced with the structure of formula (XVI) or (XVII), or a mixture of (XVI) and (XVII), the amino acid residue in SEQ ID NO:3 to be replaced is P64, m is an integer from 0 to 6, and n is an integer from about 450 to about 800, or from about 454 to about 796, or from about 454 to about 682, or from about 568 to about 909. In some embodiments of the IL-2 conjugate described herein, in the compounds of formula (XVI) and (XVII), m is 2 and n is an integer selected from 454, 455, 568, 569, 680, 681, 682, 794, 795, 796, 908, 909, and 910. In some embodiments, n is from about 500 to about 1000. In some embodiments, n is from about 550 to about 800. In some embodiments, n is about 681.

[0099] Described herein is a pharmaceutical composition comprising an effective amount of an IL-conjugate as described herein and one or more pharmaceutically acceptable excipients.

[0100] Described herein is a method of treating cancer in a subject, the method comprising administering to the subject in need thereof an effective amount of an IL-2 conjugate as described herein. In some embodiments of the method of treating cancer described herein, the cancer in the subject is renal cell carcinoma (RCC), non-small cell lung cancer (NSCLC), head and neck squamous cell carcinoma (HNSCC), classical Hodgkin lymphoma (cHL), primary mediastinal large B-cell lymphoma (PMBCL), urothelial carcinoma, microsatellite instability cancer, microsatellite stability cancer, gastric cancer, cervical cancer, hepatocellular carcinoma (HCC), Merkel cell carcinoma (MCC), melanoma, small cell lung cancer (SCLC), esophageal cancer, glioblastoma, mesothelioma, breast cancer, triple-negative breast cancer, prostate cancer, castration-resistant prostate cancer, metastatic castration-resistant prostate cancer, metastatic castration-resistant prostate cancer having a DNA damage response (DDR) defect, bladder cancer, ovarian cancer, tumors with a moderate to low mutational tumor burden, cutaneous squamous cell carcinoma (CSCC), squamous cell skin cancer (SCSC), tumors with low to no PD-L1 expression, tumors systemically seeded to the liver and CNS beyond their primary anatomic origin site, and diffuse large B-cell lymphoma. Described herein is a method of treating cancer in a subject, the method comprising administering to the subject in need thereof an effective amount of an IL-2 conjugate as described herein. In some embodiments of the method of treating cancer described herein, the cancer in the subject is cholangiocarcinoma. In some embodiments of the method of treating cancer described herein, the cancer in the subject is selected from renal cell carcinoma (RCC), non-small cell lung cancer (NSCLC), urothelial carcinoma, and melanoma. In some embodiments of the method of treating cancer described herein, the IL-2 conjugate is administered to the subject in need thereof once every two weeks, once every three weeks, once every four weeks, once every five weeks, once every six weeks, once every seven weeks, or once every eight weeks. In some embodiments of the method of treating cancer described herein, the IL-2 conjugate is administered to the subject in need thereof once a week or once every two weeks.In some embodiments of the methods of treating cancer described herein, the IL-2 conjugate is administered once per week to a subject in need thereof. In some embodiments of the methods of treating cancer described herein, the IL-2 conjugate is administered once every two weeks to a subject in need thereof. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to a subject does not cause capillary leak syndrome in the subject. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to a subject does not cause grade 2, grade 3, or grade 4 vascular leak syndrome in the subject. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to a subject does not cause grade 2 vascular leak syndrome in the subject. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to a subject does not cause grade 3 vascular leak syndrome in the subject. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to a subject does not cause grade 4 vascular leak syndrome in the subject. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to a subject does not cause absence of vasoconstriction in the subject. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to a subject does not cause extravasation of plasma proteins and fluid into the extravascular space in the subject. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to a subject does not cause hypotension and decreased organ perfusion in the subject. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to a subject does not cause neutrophil dysfunction in the subject. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to a subject does not cause decreased chemotaxis in the subject. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to a subject is not associated with an increased risk of disseminated infection. In some embodiments of the methods of treating cancer described herein, disseminated infection is sepsis or bacterial endocarditis. In some embodiments of the methods of treating cancer described herein, disseminated infection is sepsis. In some embodiments of the methods of treating cancer described herein, disseminated infection is bacterial endocarditis.In some embodiments of the methods of treating cancer described herein, the subject is treated for any existing bacterial infections prior to administration of the IL-2 conjugate. In some embodiments of the methods of treating cancer described herein, the subject is treated with an antibacterial agent selected from oxacillin, nafcillin, ciprofloxacin, and vancomycin prior to administration of the IL-2 conjugate. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to the subject does not exacerbate an existing or initial presentation of an autoimmune disease or inflammatory disorder in the subject. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to the subject does not exacerbate an existing or initial presentation of an autoimmune disease in the subject. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to the subject does not exacerbate an existing or initial presentation of an inflammatory disorder in the subject. In some embodiments of the methods of treating cancer described herein, the autoimmune disease or inflammatory disorder in the subject is selected from Crohn's disease, scleroderma, thyroiditis, inflammatory arthritis, type 1 diabetes, oculo-bulbar myasthenia gravis, crescentic IgA glomerulonephritis, cholecystitis, cerebral vasculitis, Stevens-Johnson syndrome, and pemphigus. In some embodiments of the methods of treating cancer described herein, the autoimmune disease or inflammatory disorder in the subject is Crohn's disease. In some embodiments of the methods of treating cancer described herein, the autoimmune disease or inflammatory disorder in the subject is scleroderma. In some embodiments of the methods of treating cancer described herein, the autoimmune disease or inflammatory disorder in the subject is thyroiditis. In some embodiments of the methods of treating cancer described herein, the autoimmune disease or inflammatory disorder in the subject is inflammatory arthritis. In some embodiments of the methods of treating cancer described herein, the autoimmune disease or inflammatory disorder in the subject is type 1 diabetes. In some embodiments of the methods of treating cancer described herein, the autoimmune disease or inflammatory disorder in the subject is oculo-bulbar myasthenia gravis.In some embodiments of the methods of treating cancer described herein, the autoimmune disease or inflammatory disorder in the subject is crescentic IgA glomerulonephritis. In some embodiments of the methods of treating cancer described herein, the autoimmune disease or inflammatory disorder in the subject is cholecystitis. In some embodiments of the methods of treating cancer described herein, the autoimmune disease or inflammatory disorder in the subject is cerebral vasculitis. In some embodiments of the methods of treating cancer described herein, the autoimmune disease or inflammatory disorder in the subject is Stevens-Johnson syndrome. In some embodiments of the methods of treating cancer described herein, the autoimmune disease or inflammatory disorder in the subject is pemphigoid. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to the subject does not cause a change in mental state, language disorder, cortical blindness, limb or gait ataxia, hallucinations, agitation, relaxation, or lethargy in the subject. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to the subject does not cause seizures in the subject. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to the subject is not contraindicated in subjects having a known seizure disorder. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to the subject does not cause capillary leak syndrome in the subject. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to the subject does not cause grade 2, grade 3, or grade 4 capillary leak syndrome in the subject. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to the subject does not cause grade 2 capillary leak syndrome in the subject. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to the subject does not cause grade 3 capillary leak syndrome in the subject. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to the subject does not cause grade 4 capillary leak syndrome in the subject.In some embodiments of the method of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to a subject does not cause a decrease in the mean arterial pressure in the subject after administration of the IL-2 conjugate to the subject. In some embodiments of the method of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to a subject does not cause hypotension in the subject after administration of the IL-2 conjugate to the subject. In some embodiments of the method of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to a subject does not cause a decrease of less than 90 mmHg or 20 mmHg from the baseline systolic pressure of the subject's systolic pressure after administration of the IL-2 conjugate to the subject. In some embodiments of the method of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to a subject does not cause edema in the subject after administration of the IL-2 conjugate to the subject. In some embodiments of the method of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to a subject does not cause impairment of kidney or liver function in the subject after administration of the IL-2 conjugate to the subject. In some embodiments of the method of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to a subject does not cause eosinophilia in the subject after administration of the IL-2 conjugate to the subject. In some embodiments of the method of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to a subject does not cause an eosinophil count in the peripheral blood of the subject of more than 500 per μL after administration of the IL-2 conjugate to the subject. In some embodiments of the method of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to a subject does not cause an eosinophil count in the peripheral blood of the subject of more than 500 to more than 1500 per μL after administration of the IL-2 conjugate to the subject. In some embodiments of the method of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to a subject does not cause an eosinophil count in the peripheral blood of the subject of more than 1500 to more than 5000 per μL after administration of the IL-2 conjugate to the subject.In some embodiments of the methods of treating cancer described herein, administration of an effective amount of an IL-2 conjugate to a subject does not cause an eosinophil count in the subject's peripheral blood of greater than 5000 per microliter after administration of the IL-2 conjugate to the subject. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of an IL-2 conjugate to a subject is not contraindicated for the subject in the current regimen of psychotropic medications.

[0101] In some embodiments of the methods of treating cancer described herein, administration of an effective amount of an IL-2 conjugate to a subject is not contraindicated in the subject in the current regimen of a nephrotoxic, myelotoxic, cardiotoxic, or hepatotoxic agent. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of an IL-2 conjugate to a subject is not contraindicated in the subject in the current regimen of an aminoglycoside, cytotoxic chemotherapy, doxorubicin, methotrexate, or asparaginase. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of an IL-2 conjugate to a subject is not contraindicated in a subject receiving a combination regimen containing an antineoplastic agent. In some embodiments of the methods of treating cancer described herein, the antineoplastic agent is selected from dacarbazine, cis-platinum, tamoxifen, and interferon-alpha. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of an IL-2 conjugate to a subject does not cause one or more grade 4 adverse events in the subject after administration of the IL-2 conjugate to the subject. In some embodiments of the methods of treating cancer described herein, one or more grade 4 adverse events are selected from hypothermia; shock; bradycardia; ventricular premature contractions; myocardial ischemia; syncope; hemorrhage; atrial arrhythmia; phlebitis; second-degree atrioventricular block; endocarditis; pericardial effusion; peripheral gangrene; thrombosis; coronary artery disorder; stomatitis; nausea and vomiting; abnormal liver function tests; gastrointestinal hemorrhage; hematemesis; bloody diarrhea; gastrointestinal disorder; intestinal perforation; pancreatitis; anemia; leukopenia; leukocytosis; hypocalcemia; increased alkaline phosphatase; increased blood urea nitrogen (BUN); hyperuricemia; increased non-protein nitrogen (NPN); respiratory acidosis; somnolence; agitation; neuropathy; delusional reaction; convulsions; grand mal convulsions; delirium; asthma, pulmonary edema; hyperventilation; hypoxia; hemoptysis; hypoventilation; pneumothorax; mydriasis; pupillary disorder; abnormal renal function; renal failure; and acute renal tubular necrosis. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of an IL-2 conjugate to a group of subjects does not cause one or more grade 4 adverse events in more than 1% of the subjects after administration of the IL-2 conjugate to the subjects.In some embodiments of the methods of treating cancer described herein, one or more Grade 4 adverse events are hypothermia; shock; bradycardia; ventricular premature contractions; myocardial ischemia; syncope; hemorrhage; atrial arrhythmia; phlebitis; second-degree atrioventricular block; endocarditis; pericardial effusion; peripheral gangrene; thrombosis; coronary artery disorder; stomatitis; nausea and vomiting; abnormal liver function tests; gastrointestinal hemorrhage; hematemesis; bloody diarrhea; gastrointestinal disorder; intestinal perforation; pancreatitis; anemia; leukopenia; leukocytosis; hypocalcemia; increased alkaline phosphatase; increased blood urea nitrogen (BUN); hyperuricemia; increased non-protein nitrogen (NPN); respiratory acidosis; somnolence; agitation; neuropathy; delusional reaction; convulsion; grand mal convulsion; delirium; asthma, pulmonary edema; hyperventilation; hypoxia; hemoptysis; hypoventilation; pneumothorax; mydriasis; pupillary disorder; abnormal renal function; renal failure; and acute tubular necrosis. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of an IL-2 conjugate to a group of subjects does not cause one or more adverse events in more than 1% of the subjects after administration of the IL-2 conjugate to the subjects, and one or more adverse events are duodenal ulcer; intestinal necrosis; myocarditis; supraventricular tachycardia; permanent or transient blindness secondary to optic neuritis; transient ischemic attack; meningitis; cerebral edema; pericarditis; allergic interstitial nephritis; and tracheoesophageal fistula. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of an IL-2 conjugate to a group of subjects does not cause one or more adverse events in more than 1% of the subjects after administration of the IL-2 conjugate to the subjects, and one or more adverse events are malignant hyperthermia; cardiac arrest; myocardial infarction; pulmonary embolism; seizure; intestinal perforation; liver or renal failure; severe depression leading to suicide; pulmonary edema; respiratory arrest; respiratory insufficiency. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of an IL-2 conjugate to a subject does not result in the production of neutralizing antibodies against the IL-2 conjugate. In some embodiments of the methods of treating cancer described herein, administration of an IL-2 conjugate to a subject increases the number of the subject's peripheral CD8+ T and NK cells and does not increase the number of the subject's peripheral CD4+ regulatory T cells.In some embodiments of the methods of treating cancer described herein, administration of the IL-2 conjugate to a subject increases the number of the subject's peripheral CD8+ T and NK cells and does not increase the number of the subject's peripheral eosinophils. In some embodiments of the methods of treating cancer described herein, administration of the IL-2 conjugate to a subject increases the number of the subject's intratumoral CD8+ T and NK cells and does not increase the number of the subject's intratumoral CD4+ regulatory T cells. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to a subject does not require the availability of an intensive care facility or a skilled specialist in cardiopulmonary or intensive care medicine. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to a subject does not require the availability of an intensive care facility. In some embodiments of the methods of treating cancer described herein, administration of an effective amount of the IL-2 conjugate to a subject does not require the availability of a skilled specialist in cardiopulmonary or intensive care medicine.

[0102] The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the invention will be obtained from the following detailed description that illustrates exemplary embodiments in which the principles of the invention are utilized, and from the appended drawings.

Brief Description of the Drawings

[0103]

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Mode for Carrying Out the Invention

[0104] Cytokines include a family of cell signaling proteins, such as chemokines, interferons, interleukins, lymphokines, tumor necrosis factors, and other growth factors that play a role in innate and adaptive immune cell homeostasis. Cytokines are produced by immune cells, such as macrophages, B lymphocytes, T lymphocytes and mast cells, endothelial cells, fibroblasts, and various stromal cells, etc. In some examples, cytokines regulate the balance between the humoral immune response and the cellular immune response.

[0105] Interleukins are signaling proteins that regulate the development and differentiation of T and B lymphocytes, cells of the monocyte lineage, neutrophils, basophils, eosinophils, megakaryocytes, and hematopoietic cells. Interleukins are produced by CD4 T and B lymphocytes, monocytes, macrophages, endothelial cells, and other tissue resident cells.

[0106] Interleukin 2 (IL-2) is a multifaceted type-1 cytokine, and its structure contains a four α-helix bundle of 15.5 kDa. The precursor of IL-2 is 153 amino acid residues in length, with the first 20 amino acids forming the signal peptide and the remaining 21 - 153 forming the mature form. IL-2 is mainly produced by CD4+ T cells after antigen stimulation, although to a lesser extent by CD8+ cells, natural killer (NK) cells, natural killer T (NKT) cells, activated dendritic cells (DCs), and mast cells. IL-2 signaling occurs through interaction with a specific combination of IL-2 receptor (IL-2R) subunits, IL-2Rα (also known as CD25), IL-2Rβ (also known as CD122), and IL-2Rγ (also known as CD132). The interaction between IL-2 and IL-2Rα forms a "low-affinity" IL-2 receptor complex at approximately 10 -8 M of K d The interaction between IL-2 and IL-2Rβ and IL-2Rγ forms a "medium-affinity" IL-2 receptor complex at approximately 10 -9 M of K d The interaction between IL-2 and all three subunits, IL-2Rα, IL-2Rβ, and IL-2Rγ, forms a "high-affinity" IL-2 receptor complex at approximately >10 -11 M of K d In some cases, IL-2 signaling via the "high-affinity" IL-2Rαβγ complex regulates the activation and proliferation of regulatory T cells. Regulatory T cells, or CD4

[0107] In some examples, IL-2 signaling via the "high-affinity" IL-2Rαβγ complex regulates the activation and proliferation of regulatory T cells. Regulatory T cells, or CD4 + CD25 + Foxp3 + Regulatory T (Treg) cells are effector cells, e.g., CD4+ T cells, CD8 + Maintains immune homeostasis by suppressing T cells, B cells, NK cells, and NKT cells. In some examples, Treg cells arise from the thymus (tTreg cells) or are induced from naive T cells in the periphery (pTreg cells). In some cases, Treg cells are regarded as mediators of peripheral tolerance. Indeed, in one study, transplantation of CD25-depleted peripheral CD4 + T cells resulted in various autoimmune diseases in nude mice, while co-transplantation of CD4 + CD25 + T cells suppressed the development of autoimmunity (Sakaguchi, et al., "Immunologic self-tolerance maintained by activated T cells expressing IL-2 receptor alpha-chains (CD25)" J. Immunol. 155(3):1151~1164 (1995)). Expansion of the Treg cell population downregulates effector T cell proliferation and suppresses autoimmunity and the T cell anti-tumor response.

[0108] IL-2 signaling via the "intermediate affinity" IL-2Rβγ complex regulates the activation and proliferation of CD8 + effector T (Teff) cells, NK cells, and NKT cells. CD8 + Teff cells (also known as cytotoxic T cells, Tc cells, cytotoxic T lymphocytes, CTLs, T killer cells, cytolytic T cells, Tcon, or killer T cells) are T lymphocytes that recognize and kill damaged cells, cancerous cells, and pathogen-infected cells. NK and NKT cells are CD8 + lymphocytes of a type similar to Teff cells, target cancerous cells, and pathogen-infected cells.

[0109] In some examples, IL-2 signaling regulates T cell responses and is subsequently utilized in cancer treatment. For example, IL-2 is administered at high doses to induce the expansion of Teff cell populations for cancer treatment. However, high-dose IL2 also further induces the concomitant stimulation of Treg cells that blunt the anti-tumor immune response. High-dose IL-2 also induces toxic adverse events mediated by the involvement of IL-2R alpha chain-expressing cells in the vasculature, including type 2 innate immune cells (ILC-2), eosinophils, and endothelial cells. This results in eosinophilia, capillary leak, and vascular leak syndrome (VLS).

[0110] Adoptive cell therapy enables physicians to effectively utilize a patient's own immune cells to combat diseases such as proliferative diseases (e.g., cancer) and infections. In one non-limiting example, T lymphocytes are collected from a patient, re-engineered to target specific antigens on the surface of malignant cells, and reintroduced into the patient's body to specifically target malignant cells. Additionally, adoptive cell therapy provides a sustained response in the body through signaling to immune cells that grow and divide immune cells long after the re-engineered cells have been reintroduced into the patient's immune system.

[0111] Described herein is, in certain embodiments, a method of selectively upregulating separate populations of lymphocytes (e.g., CD4+ helper cells, CD8+ effector naive and memory cells, NK cells, or NKT cells) via cytokine / cytokine receptor signaling. In some examples, the cytokine includes interleukin, interferon, or tumor necrosis factor. Optionally, the cytokine is a cytokine conjugate, such as an interleukin conjugate, an interferon conjugate, or a tumor necrosis factor conjugate. Additionally, pharmaceutical compositions and kits comprising one or more of the cytokine conjugates described herein are included herein.

[0112] In some embodiments, described herein is also a method of selectively upregulating CD4+ helper cells, CD8+ effector naive and memory cells, NK cells, and / or NKT cell populations via IL-2 / IL-2R signaling. In some examples, the IL-2 is an IL-2 conjugate that, optionally, has a potency similar to the IL-2Rαβγ complex and interacts with the "mid-affinity" IL-2Rβγ complex with a weak IL-2Rα interaction, compared to wild-type IL-2. In some embodiments, methods of treating cancer using the IL-2 conjugates described herein are further described herein. In additional embodiments, described herein are pharmaceutical compositions and kits comprising one or more of the IL-2 conjugates described herein. In some embodiments, the IL-2 conjugate comprises a conjugating moiety (e.g., PEG) that contributes to an increase or decrease in the "clearance rate", or plasma half-life, in a subject without affecting the pharmacokinetics, including the desired cytokine-receptor interaction and immune cell expansion.

[0113] Described herein is, in some embodiments, a reagent used to develop adoptive cell therapies comprising cells engineered to express a modified cytokine that results in selective cytokine-receptor interactions and immune cell expansion. In some embodiments, the reagent comprises a nucleic acid construct encoding the above-described IL-2 conjugate. Also disclosed are adoptive cell therapies comprising the above-described IL-2 conjugate useful for the treatment of proliferative or infectious diseases described herein.

[0114] Described herein is, in some embodiments, a composition that results in selective cytokine-receptor interactions and immune cell expansion. In some embodiments, the reagent comprises a nucleic acid construct encoding the above-described IL-2 conjugate. Also disclosed are pharmaceutical compositions comprising the above-described IL-2 conjugate useful for the treatment of proliferative or infectious diseases described herein.

[0115] Cytokine conjugate In some embodiments, described herein is a cytokine conjugate. In some examples, the cytokine includes an interleukin, a tumor necrosis factor, an interferon, a chemokine, a lymphokine, or a growth factor. In some examples, the cytokine is an interleukin. In some cases, the cytokine is an interferon. In additional cases, the cytokine is a tumor necrosis factor. In further cases, the cytokine is a growth factor.

[0116] In some embodiments, described herein is an interleukin conjugate. Exemplary interleukins include, but are not limited to, interleukin 2 (IL-2).

[0117] IL-2 conjugate Described herein is the polypeptide shown in Table 20. In some embodiments, the IL-2 conjugate described herein is exemplified in Table 20.

[0118] [Table 1-1] [Table 1-2] [Table 1-3] [Table 1-4] [Table 1-5] [Table 1-6] [Table 1-7]

[0119] In some embodiments, this specification describes an IL-2 conjugate modified at a certain amino acid position. In some examples, the modification is a change to a natural amino acid. In some examples, the modification is a change to a non-natural amino acid. In some examples, this specification describes an isolated and modified IL-2 polypeptide comprising at least one non-natural amino acid. In some examples, the IL-2 polypeptide is an isolated and purified mammalian IL-2, such as a rodent IL-2 protein, or a human IL-2 protein. In some cases, the IL-2 polypeptide is a human IL-2 protein. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 1. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 1. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 1. In additional cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 2. In additional cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 2. In additional cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 2. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 3. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 3. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 3. In additional cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 4. In additional cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 4. In additional cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 4. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 5. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 5. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 5.In the case of addition, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 6. In the case of addition, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 6. In the case of addition, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 6. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 7. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 7. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 7. In the case of addition, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 8. In the case of addition, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 8. In the case of addition, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 8. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 9. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 9. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 9. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 10. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 10. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 10. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 11. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 11. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 11. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 12. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 12. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 12.In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 13. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 13. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 13. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 14. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 14. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 14. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 15. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 15. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 15. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 16. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 16. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 16. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 17. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 17. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 17. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 18. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 18. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 18. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 19. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 19. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 19.In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 20. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 20. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 20. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 21. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 21. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 21. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 22. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 22. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 22. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 23. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 23. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 23. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 24. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 24. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 24. Additionally, in some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 25. Additionally, in some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 25. Additionally, in some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 25. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 26. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 26. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 26.In the case of an addition, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 27. In the case of an addition, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 27. In the case of an addition, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 27. Optionally, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 28. Optionally, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 28. Optionally, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 28. In the case of an addition, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 29. In the case of an addition, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 29. In the case of an addition, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 29. Optionally, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 30. Optionally, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 30. Optionally, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 30. Optionally, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 31. Optionally, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 31. Optionally, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 31. In the case of an addition, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 32. In the case of an addition, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 32. In the case of an addition, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 32. Optionally, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 33. Optionally, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 33. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 33. In additional cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 34. In additional cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 34. In additional cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 34. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 35. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 35. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 35. In additional cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 36. In additional cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 36. In additional cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 36. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 37. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 37. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 37. In additional cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 38. In additional cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 38. In additional cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 38. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 39. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 39. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 39. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 40. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 40.In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 40. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 41. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 41. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 41. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 42. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 42. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 42. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 43. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 43. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 43. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 44. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 44. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 44. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 45. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 45. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 45. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 46. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 46. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 46. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 47. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 47.In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 47. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 48. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 48. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 48. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 49. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 49. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 49. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 50. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 50. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 50. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 51. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 51. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 51. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 52. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 52. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 52. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 53. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 53. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 53. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 54. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 54.In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 54. In additional cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 55. In additional cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 55. In additional cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 55. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 56. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 56. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 56. In additional cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 57. In additional cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 57. In additional cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 57. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 58. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 58. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 58. In additional cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 59. In additional cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 59. In additional cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 59. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 60. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 60. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 60. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 61. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 61.In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 61. In additional cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 62. In additional cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 62. In additional cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 62. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 63. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 63. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 63. In additional cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 64. In additional cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 64. In additional cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 64. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 65. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 65. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 65. In additional cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 66. In additional cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 66. In additional cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 66. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 67. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 67. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 67. In additional cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 68. In the case of addition, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 68. In the case of addition, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 68. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 69. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 69. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 69. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 70. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 70. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 70. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 71. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 71. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 71. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 72. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 72. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 72. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 73. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 73. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 73. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 74. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 74. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 74. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 75.In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 75. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 75. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 76. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 76. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 76. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 77. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 77. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 77. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 78. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 78. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 78. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 79. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 79. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 79. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 80. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 80. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 80. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 81. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 81. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 81. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 82.In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 82. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 82. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 83. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 83. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 83. In some cases, the IL-2 polypeptide comprises about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 84. In some cases, the IL-2 polypeptide comprises the sequence of SEQ ID NO: 84. In some cases, the IL-2 polypeptide consists of the sequence of SEQ ID NO: 84.

[0120] In some examples, the IL-2 polypeptide is a truncated variant. In some examples, the truncation is an N-terminal deletion. In other examples, the truncation is a C-terminal deletion. In additional examples, the truncation includes deletions of both the N-terminal and C-terminal. For example, the truncation can be a deletion of at least or about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20 or more residues from the N-terminal or C-terminal, or both termini. In some cases, the IL-2 polypeptide includes an N-terminal deletion of at least or about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20 or more residues. In some cases, the IL-2 polypeptide includes an N-terminal deletion of at least or about 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 residues. In some cases, the IL-2 polypeptide includes an N-terminal deletion of at least or about 2 residues. In some cases, the IL-2 polypeptide includes an N-terminal deletion of at least or about 3 residues. In some cases, the IL-2 polypeptide includes an N-terminal deletion of at least or about 4 residues. In some cases, the IL-2 polypeptide includes an N-terminal deletion of at least or about 5 residues. In some cases, the IL-2 polypeptide includes an N-terminal deletion of at least or about 6 residues. In some cases, the IL-2 polypeptide includes an N-terminal deletion of at least or about 7 residues. In some cases, the IL-2 polypeptide includes an N-terminal deletion of at least or about 8 residues. In some cases, the IL-2 polypeptide includes an N-terminal deletion of at least or about 9 residues. In some cases, the IL-2 polypeptide includes an N-terminal deletion of at least or about 10 residues.

[0121] In some embodiments, the IL-2 polypeptide is a functionally active fragment. Optionally, the functionally active fragment comprises IL-2 region 10-133, 20-133, 30-133, 10-130, 20-130, 30-130, 10-125, 20-125, 30-125, 1-130, or 1-125, and the residue positions are based on the positions of SEQ ID NO: 1. Optionally, the functionally active fragment comprises IL-2 region 10-133, and the residue positions are based on the positions of SEQ ID NO: 1. Optionally, the functionally active fragment comprises IL-2 region 20-133, and the residue positions are based on the positions of SEQ ID NO: 1. Optionally, the functionally active fragment comprises IL-2 region 30-133, and the residue positions are based on the positions of SEQ ID NO: 1. Optionally, the functionally active fragment comprises IL-2 region 10-125, and the residue positions are based on the positions of SEQ ID NO: 1. Optionally, the functionally active fragment comprises IL-2 region 20-125, and the residue positions are based on the positions of SEQ ID NO: 1. Optionally, the functionally active fragment comprises IL-2 region 1-130, and the residue positions are based on the positions of SEQ ID NO: 1. Optionally, the functionally active fragment comprises IL-2 region 1-125, and the residue positions are based on the positions of SEQ ID NO: 1.

[0122] In some embodiments, described herein is an IL-2 conjugate comprising an isolated, purified, and modified IL-2 polypeptide and a conjugated moiety. In some examples, the IL-2 conjugate has a reduced affinity for the interleukin-2 receptor alpha (IL-2Rα) subunit as compared to the wild-type IL-2 polypeptide. Optionally, the conjugated moiety binds to an amino acid residue that interacts with IL-2Rα (e.g., the IL-2 / IL-2Rα interface). Optionally, the conjugated moiety binds to an amino acid residue proximal to the IL-2 / IL-2Rα interface (e.g., about 5 Å, about 10 Å, about 15 Å, or about 20 Å away from the IL-2 / IL-2Rα interface). As used herein, residues involved in the IL-2 / IL-2Rα interface include IL-2 residues that form hydrophobic, hydrogen, or ionic interactions with residues from the IL-2Rα subunit.

[0123] In some examples, the conjugated portion binds to an amino acid residue selected from amino acid positions Y31, K32, N33, P34, K35, T37, R38, T41, F42, K43, F44, Y45, P47, K48, Q57, E60, E61, E62, L63, K64, P65, E68, V69, N71, L72, Q74, S75, K76, N77, M104, C105, E106, Y107, A108, D109, E110, T111, or A112, and the numbering of the amino acid residues corresponds to SEQ ID NO: 1. In some examples, the amino acid positions are selected from Y31, K32, N33, P34, K35, T37, R38, T41, F42, K43, F44, Y45, P47, K48, E61, E62, E68, K64, P65, V69, L72, Q74, S75, K76, N77, M104, C105, E106, Y107, A108, D109, E110, T111, and A112. In some examples, the amino acid positions are selected from N33, P34, K35, T37, R38, M39, T41, F42, K43, F44, Y45, Q57, E60, E61, E62, L63, K64, P65, E68, V69, N71, L72, M104, C105, E106, Y107, A108, D109, E110, T111, and A112. In some examples, the amino acid positions are selected from K35, T37, R38, T41, F42, K43, F44, Y45, E61, E62, E68, K64, P65, V69, L72, and Y107. In some examples, the amino acid positions are selected from T37, R38, T41, F42, F44, Y45, E61, E62, E68, K64, P65, V69, L72, and Y107. In some examples, the amino acid positions are selected from T37, R38, T41, F42, F44, Y45, E61, E62, E68, P65, V69, L72, and Y107. In some examples, the amino acid positions are selected from T37, T41, F42, F44, Y45, P65, V69, L72, and Y107. In some examples, the amino acid positions are selected from R38 and K64. In some examples, the amino acid positions are selected from E61, E62, and E68. In some cases, the amino acid position is at K35. In some cases, the amino acid position is at T37.In some cases, the amino acid position is at R38. In some cases, the amino acid position is at T41. In some cases, the amino acid position is at F42. In some cases, the amino acid position is at K43. In some cases, the amino acid position is at F44. In some cases, the amino acid position is at Y45. In some cases, the amino acid position is at E61. In some cases, the amino acid position is at E62. In some cases, the amino acid position is at K64. In some cases, the amino acid position is at E68. In some cases, the amino acid position is at P65. In some cases, the amino acid position is at V69. In some cases, the amino acid position is at L72. In some cases, the amino acid position is at Y107. In some cases, the amino acid position is at L72. In some cases, the amino acid position is at D109.

[0124] In some examples, the IL-2 conjugate further comprises additional mutations. In some cases, the additional mutations are at amino acid positions selected from K35, T37, R38, T41, F42, K43, F44, Y45, E61, E62, E68, K64, P65, V69, L72, and Y107. In such cases, the amino acid is conjugated to an additional conjugating moiety for increased serum half-life, stability, or a combination thereof. Alternatively, the amino acid is first mutated to a natural amino acid, such as lysine, cysteine, histidine, arginine, aspartic acid, glutamic acid, serine, threonine, or tyrosine; or to a non-natural amino acid before binding to the additional conjugating moiety.

[0125] In some embodiments, the reduced affinity of the modified IL-2 polypeptide for the IL-2 receptor α (IL-2Rα) subunit, as compared to the wild-type IL-2 polypeptide without non-natural amino acid modification (e.g., wild-type IL-2 polypeptide), is about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, or 99%, or more than 99%. In some cases, the reduced affinity is about 10%. In some cases, the reduced affinity is about 20%. In some cases, the reduced affinity is about 40%. In some cases, the reduced affinity is about 50%. In some cases, the reduced affinity is about 60%. In some cases, the reduced affinity is about 80%. In some cases, the reduced affinity is about 90%. In some cases, the reduced affinity is about 99%. In some cases, the reduced affinity is more than about 99%. In some cases, the reduced affinity is about 80%. In some cases, the reduced affinity is about 100%.

[0126] In some embodiments, the modified IL-2 polypeptide has a reduced affinity for the IL-2 receptor α (IL-2Rα) subunit, as compared to an equivalent IL-2 polypeptide without non-natural amino acid modification (e.g., a wild-type IL-2 polypeptide), of about 1-fold, 2-fold, 3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold, 10-fold, 30-fold, 50-fold, 100-fold, 200-fold, 300-fold, 400-fold, 500-fold, 1,000-fold, or more. In some cases, the reduced affinity is about 1-fold. In some cases, the reduced affinity is about 2-fold. In some cases, the reduced affinity is about 4-fold. In some cases, the reduced affinity is about 5-fold. In some cases, the reduced affinity is about 6-fold. In some cases, the reduced affinity is about 8-fold. In some cases, the reduced affinity is about 10-fold. In some cases, the reduced affinity is about 30-fold. In some cases, the reduced affinity is about 50-fold. In some cases, the reduced affinity is about 100-fold. In some cases, the reduced affinity is about 300-fold. In some cases, the reduced affinity is about 500-fold. In some cases, the reduced affinity is about 1,000-fold. In some cases, the reduced affinity is greater than 1,000-fold.

[0127] In some cases, the modified IL-2 polypeptide does not interact with IL-2Rα. In some examples, the modified IL-2 polypeptide is further conjugated to a conjugating moiety. In some cases, the IL-2 conjugate does not interact with IL-2Rα.

[0128] In some embodiments, the modified IL-2 polypeptide exhibits a first receptor signaling efficacy with respect to the IL-2βγ signaling complex and a second receptor signaling efficacy with respect to the IL-2αβγ signaling complex, and the difference between the first receptor signaling efficacy and the second receptor signaling efficacy is less than 10-fold. In some embodiments, the modified IL-2 polypeptide exhibits a first receptor signaling efficacy with respect to the IL-2βγ signaling complex and a second receptor signaling efficacy with respect to the IL-2αβγ signaling complex, and the difference between the first receptor signaling efficacy and the second receptor signaling efficacy is less than 5-fold. In some examples, the difference is less than 9-fold, less than 8-fold, less than 7-fold, less than 6-fold, less than 5-fold, less than 4-fold, less than 3-fold, less than 2-fold, or less than 1-fold. In some examples, the modified IL-2 polypeptide is a partial agonist, e.g., an agonist that activates a receptor (e.g., the IL-2βγ signaling complex or the IL-2αβγ signaling complex) but has only partial efficacy at the receptor compared to a full agonist. In some examples, the modified IL-2 polypeptide is a full agonist, e.g., an agonist that activates a receptor (e.g., the IL-2βγ signaling complex or the IL-2αβγ signaling complex) with a maximal response.

[0129] In some examples, receptor signaling efficacy is measured by an EC50 value. In some examples, the modified IL-2 polypeptide provides a first EC50 value for activating the IL-2βγ signaling complex and a second EC50 value for activating the IL-2αβγ signaling complex, and the difference between the first EC50 value and the second EC50 value is less than 10-fold. In some examples, the modified IL-2 polypeptide provides a first EC50 value for activating the IL-2βγ signaling complex and a second EC50 value for activating the IL-2αβγ signaling complex, and the difference between the first EC50 value and the second EC50 value is less than 5-fold. Optionally, the difference is less than 9-fold, less than 8-fold, less than 7-fold, less than 6-fold, less than 5-fold, less than 4-fold, less than 3-fold, less than 2-fold, or less than 1-fold.

[0130] In some examples, receptor signaling efficacy is measured by an ED50 value. In some examples, a modified IL-2 polypeptide provides a first ED50 value for activating an IL-2βγ signaling complex and a second ED50 value for activating an IL-2αβγ signaling complex, and the difference between the first ED50 value and the second ED50 value is less than 10-fold. In some examples, a modified IL-2 polypeptide provides a first ED50 value for activating an IL-2βγ signaling complex and a second ED50 value for activating an IL-2αβγ signaling complex, and the difference between the first ED50 value and the second ED50 value is less than 5-fold. In some cases, the difference is less than 9-fold, less than 8-fold, less than 7-fold, less than 6-fold, less than 5-fold, less than 4-fold, less than 3-fold, less than 2-fold, or less than 1-fold.

[0131] In some embodiments, the conjugating moiety is linked to the N-terminus or C-terminus of the IL-2 polypeptide either directly or indirectly via a linker peptide. In some cases, the conjugating moiety (e.g., a polymer, protein, or peptide) is genetically fused to IL-2 at the N-terminus or C-terminus of IL-2 either directly or indirectly via a linker peptide. In some examples, the conjugating moiety is linked to an N-terminal or C-terminal amino acid residue. In some examples, the conjugating moiety is linked to a reactive group that binds to an N-terminal or C-terminal amino acid residue.

[0132] In some embodiments, an IL-2 conjugate with reduced binding affinity for IL-2Rα can expand CD4+ helper cells, CD8+ effector naive and memory T cells, natural killer (NK) cells, or natural killer T (NKT) cell populations. In some cases, the conjugating moiety impairs or blocks the binding of IL-2 to IL-2Rα.

[0133] In some cases, the activation of CD4+ helper cells, CD8+ effector naive and memory cells, natural killer (NK) cells, or natural killer T (NKT) cell populations via the IL-2Rβγ complex by the modified IL-2 polypeptide retains a significant potency of activation of said cell populations as compared to the wild-type IL-2 polypeptide. In some examples, the activation by the modified IL-2 polypeptide is equivalent to that of the wild-type IL-2 polypeptide. In other examples, the activation by the modified IL-2 polypeptide is higher than that of the wild-type IL-2 polypeptide. In some cases, the receptor signaling potency of the modified IL-2 polypeptide for the IL-2Rβγ complex is higher than the receptor signaling potency of the wild-type IL-2 polypeptide for the IL-2Rβγ complex. In some cases, the receptor signaling potency of the modified IL-2 polypeptide is at least 1-fold higher than the respective potency of the wild-type IL-2 polypeptide. In some cases, the receptor signaling potency of the modified IL-2 polypeptide is about or at least 2-fold, 3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold, 10-fold, 15-fold, 20-fold, 25-fold, 30-fold, 40-fold, 50-fold, 60-fold, 70-fold, 80-fold, 90-fold, 100-fold, 150-fold, 200-fold, 300-fold, 400-fold, 500-fold, 1,000-fold, or more than the respective potency of the wild-type IL-2 polypeptide. In such cases, the dose or concentration of the modified IL-2 polypeptide used to achieve a similar level of activation of the wild-type Il-2 polypeptide and the CD4+ helper cells, CD8+ effector naive and memory cells, natural killer (NK) cells, or natural killer T (NKT) cell populations is lower than the dose or concentration used for the wild-type IL-2 polypeptide.

[0134] In some embodiments, activation of CD4+ helper cells, CD8+ effector naive and memory cells, natural killer (NK) cells, or natural killer T (NKT) cell populations via the IL-2Rβγ complex by the modified IL-2 polypeptide retains a significant potency of activation of said cell populations by the wild-type IL-2 polypeptide. In some cases, the receptor signaling potency of the modified IL-2 polypeptide for the IL-2Rβγ complex is lower than the receptor signaling potency of the wild-type IL-2 polypeptide for the IL-2Rβγ complex. In some cases, the receptor signaling potency of the modified IL-2 polypeptide is about or at least 1-fold, 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, 20-fold, or 50-fold lower than the respective potency of the wild-type IL-2 polypeptide.

[0135] In some embodiments, the modified IL-2 polypeptide exhibits a first receptor signaling efficacy for IL-2βγ and a second receptor signaling efficacy for IL-2αβγ. In some examples, the first receptor signaling efficacy for IL-2Rβγ is an improved efficacy as compared to the wild-type IL-2 polypeptide. In some examples, the second receptor signaling efficacy for IL-2Rαβγ is a compromised efficacy as compared to the wild-type IL-2 polypeptide. In some embodiments, the modified IL-2 polypeptide exhibits a first receptor signaling efficacy for IL-2βγ and a second receptor signaling efficacy for IL-2αβγ, and the first receptor signaling efficacy is at least 1-fold, 2-fold, 3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold, 10-fold, 20-fold, 30-fold, 50-fold, 100-fold, 500-fold, 1000-fold, or more than the second receptor signaling efficacy. In some examples, the first receptor signaling efficacy is at least 1-fold or more than the second receptor signaling efficacy. In some examples, the first receptor signaling efficacy is at least 2-fold or more than the second receptor signaling efficacy. In some examples, the first receptor signaling efficacy is at least 5-fold or more than the second receptor signaling efficacy. In some examples, the first receptor signaling efficacy is at least 10-fold or more than the second receptor signaling efficacy. In some examples, the first receptor signaling efficacy is at least 20-fold or more than the second receptor signaling efficacy. In some examples, the first receptor signaling efficacy is at least 50-fold or more than the second receptor signaling efficacy. In some examples, the first receptor signaling efficacy is at least 100-fold or more than the second receptor signaling efficacy. In some examples, the first receptor signaling efficacy is at least 500-fold or more than the second receptor signaling efficacy. In some examples, the first receptor signaling efficacy is at least 1000-fold or more than the second receptor signaling efficacy.In some examples, the first receptor signaling potency of the modified IL-2 polypeptide is higher than the receptor signaling potency of the wild-type IL-2 polypeptide for IL-2Rβγ, and the second receptor signaling potency of the modified IL-2 polypeptide is lower than the receptor signaling potency of the wild-type IL-2 polypeptide for IL-2Rαβγ. In some cases, both receptor signaling potencies are lower than their respective potencies in the wild-type IL-2 polypeptide. In other cases, both receptor signaling potencies are higher than their respective potencies in the wild-type IL-2 polypeptide.

[0136] In some embodiments, the IL-2 conjugate reduces toxic adverse events in a subject to which the IL-2 conjugate is administered. Exemplary toxic adverse events include eosinophilia, capillary leak, and vascular leak syndrome (VLS). In some examples, the IL-2 conjugate reduces the incidence of toxic adverse events in the subject by about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or up to about 100% compared to a second subject administered wild-type IL-2 or aldesleukin. In some examples, the IL-2 conjugate reduces the severity of toxic adverse events in the subject by about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or up to about 100% compared to a second subject administered wild-type IL-2 or aldesleukin.

[0137] In some examples, the toxic adverse event is eosinophilia. In some cases, the IL-2 conjugate reduces the occurrence of eosinophilia in the subject by about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or up to about 100% compared to a second subject administered wild-type IL-2 or aldesleukin. In some cases, the IL-2 conjugate reduces the severity of eosinophilia in the subject by about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or up to about 100% compared to a second subject administered wild-type IL-2 or aldesleukin.

[0138] In some examples, the toxic adverse event is capillary leak. In some cases, the IL-2 conjugate reduces the occurrence of capillary leak in the subject by about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or up to about 100% compared to a second subject administered wild-type IL-2 or aldesleukin. In some cases, the IL-2 conjugate reduces the severity of capillary leak in the subject by about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or up to about 100% compared to a second subject administered wild-type IL-2 or aldesleukin.

[0139] In some examples, the toxic adverse event is VLS. In some cases, the IL-2 conjugate reduces the occurrence of VLS in the subject by about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or up to about 100% compared to a second subject administered wild-type IL-2 or aldesleukin. In some cases, the IL-2 conjugate reduces the severity of VLS in the subject by about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or up to about 100% compared to a second subject administered wild-type IL-2 or aldesleukin.

[0140] In some embodiments, the IL-2 conjugate has a plasma half-life of 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 18 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, or longer. In some embodiments, the IL-2 conjugate has a plasma half-life of 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, or longer. In some embodiments, the IL-2 conjugate has a plasma half-life longer than 1 hour. In some embodiments, the IL-2 conjugate has a plasma half-life longer than 2 hours. In some embodiments, the IL-2 conjugate has a plasma half-life longer than 3 hours. In some embodiments, the IL-2 conjugate has a plasma half-life longer than 4 hours. In some embodiments, the IL-2 conjugate has a plasma half-life longer than 5 hours. In some embodiments, the IL-2 conjugate has a plasma half-life longer than 6 hours. In some embodiments, the IL-2 conjugate has a plasma half-life longer than 7 hours. In some embodiments, the IL-2 conjugate has a plasma half-life longer than 8 hours. In some embodiments, the IL-2 conjugate has a plasma half-life longer than 9 hours. In some embodiments, the IL-2 conjugate has a plasma half-life longer than 10 hours. In some embodiments, the IL-2 conjugate has a plasma half-life longer than 12 hours. In some embodiments, the IL-2 conjugate has a plasma half-life longer than 18 hours. In some embodiments, the IL-2 conjugate has a plasma half-life longer than 24 hours.

[0141] In some embodiments, the IL-2 conjugate has a plasma half-life of at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, or more. In some embodiments, the IL-2 conjugate has a plasma half-life of at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, or more. In some embodiments, the IL-2 conjugate has a plasma half-life of at least 1 hour. In some embodiments, the IL-2 conjugate has a plasma half-life of at least 2 hours. In some embodiments, the IL-2 conjugate has a plasma half-life of at least 3 hours. In some embodiments, the IL-2 conjugate has a plasma half-life of at least 4 hours. In some embodiments, the IL-2 conjugate has a plasma half-life of at least 5 hours. In some embodiments, the IL-2 conjugate has a plasma half-life of at least 6 hours. In some embodiments, the IL-2 conjugate has a plasma half-life of at least 7 hours. In some embodiments, the IL-2 conjugate has a plasma half-life of at least 8 hours. In some embodiments, the IL-2 conjugate has a plasma half-life of at least 9 hours. In some embodiments, the IL-2 conjugate has a plasma half-life of at least 10 hours. In some embodiments, the IL-2 conjugate has a plasma half-life of at least 12 hours. In some embodiments, the IL-2 conjugate has a plasma half-life of at least 18 hours. In some embodiments, the IL-2 conjugate has a plasma half-life of at least 24 hours.

[0142] In some embodiments, the IL-2 conjugate has a plasma half-life of from about 1 hour to about 7 days, from about 12 hours to about 7 days, from about 18 hours to about 7 days, from about 24 hours to about 7 days, from about 1 hour to about 5 days, from about 12 hours to about 5 days, from about 24 hours to about 5 days, from about 2 days to about 5 days, or from about 2 days to about 3 days.

[0143] In some embodiments, the IL-2 conjugate has a plasma half-life of about 1 hour to about 18 hours, about 1 hour to about 12 hours, about 2 hours to about 10 hours, about 2 hours to about 8 hours, about 4 hours to about 18 hours, about 4 hours to about 12 hours, about 4 hours to about 10 hours, about 4 hours to about 8 hours, about 6 hours to about 18 hours, about 6 hours to about 12 hours, about 6 hours to about 10 hours, about 6 hours to about 8 hours, about 8 hours to about 18 hours, about 8 hours to about 12 hours, or about 8 hours to about 10 hours.

[0144] In some embodiments, the IL-2 conjugate has a plasma half-life that can proliferate and / or expand CD4+ helper cells, CD8+ effector naive and memory T cells, NK cells, NKT cells, or combinations thereof, and does not exert harmful effects such as apoptosis.

[0145] In some embodiments, the IL-2 conjugate has an extended plasma half-life of at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, or more as compared to, for example, wild-type IL-2. In some embodiments, the IL-2 conjugate has an extended plasma half-life of at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, or more as compared to, for example, wild-type IL-2.

[0146] In some embodiments, the IL-2 conjugate has an extended plasma half-life of about 1 hour to about 18 hours, about 1 hour to about 12 hours, about 2 hours to about 10 hours, about 2 hours to about 8 hours, about 4 hours to about 18 hours, about 4 hours to about 12 hours, about 4 hours to about 10 hours, about 4 hours to about 8 hours, about 6 hours to about 18 hours, about 6 hours to about 12 hours, about 6 hours to about 10 hours, about 6 hours to about 8 hours, about 8 hours to about 18 hours, about 8 hours to about 12 hours, or about 8 hours to about 10 hours as compared to, for example, wild-type IL-2.

[0147] In some embodiments, the IL-2 conjugate includes an extended plasma half-life of at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, or more as compared to, for example, Aldesleukin. In some embodiments, the IL-2 conjugate includes an extended plasma half-life of at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, or more as compared to, for example, Aldesleukin.

[0148] In some embodiments, the IL-2 conjugate includes an extended plasma half-life of about 1 hour to about 18 hours, about 1 hour to about 12 hours, about 2 hours to about 10 hours, about 2 hours to about 8 hours, about 4 hours to about 18 hours, about 4 hours to about 12 hours, about 4 hours to about 10 hours, about 4 hours to about 8 hours, about 6 hours to about 18 hours, about 6 hours to about 12 hours, about 6 hours to about 10 hours, about 6 hours to about 8 hours, about 8 hours to about 18 hours, about 8 hours to about 12 hours, or about 8 hours to about 10 hours as compared to, for example, Aldesleukin.

[0149] In some embodiments, the IL-2 conjugate has an extended plasma half-life and reduced toxicity. In some examples, the IL-2 conjugate has an extended plasma half-life of at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, or more, and reduced toxicity. In some examples, the IL-2 conjugate has an extended plasma half-life of at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, or more, and reduced toxicity. In some examples, the IL-2 conjugate has an extended plasma half-life of about 1 hour to about 18 hours, about 1 hour to about 12 hours, about 2 hours to about 10 hours, about 2 hours to about 8 hours, about 4 hours to about 18 hours, about 4 hours to about 12 hours, about 4 hours to about 10 hours, about 4 hours to about 8 hours, about 6 hours to about 18 hours, about 6 hours to about 12 hours, about 6 hours to about 10 hours, about 6 hours to about 8 hours, about 8 hours to about 18 hours, about 8 hours to about 12 hours, or about 8 hours to about 10 hours, and reduced toxicity. In some cases, the reduced toxicity is at least 1-fold, 2-fold, 3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold, 10-fold, 20-fold, 30-fold, 50-fold, 100-fold, or more reduced compared to wild-type IL2. In some cases, the reduced toxicity is at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 200%, 300%, 400%, 500%, or more reduced compared to wild-type IL-2.

[0150] In some embodiments, the IL-2 conjugate has an extended plasma half-life and reduced toxicity. In some examples, the IL-2 conjugate has an extended plasma half-life of at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, or more, and reduced toxicity. In some examples, the IL-2 conjugate has an extended plasma half-life of at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, or more, and reduced toxicity. In some examples, the IL-2 conjugate has an extended plasma half-life of about 1 hour to about 18 hours, about 1 hour to about 12 hours, about 2 hours to about 10 hours, about 2 hours to about 8 hours, about 4 hours to about 18 hours, about 4 hours to about 12 hours, about 4 hours to about 10 hours, about 4 hours to about 8 hours, about 6 hours to about 18 hours, about 6 hours to about 12 hours, about 6 hours to about 10 hours, about 6 hours to about 8 hours, about 8 hours to about 18 hours, about 8 hours to about 12 hours, or about 8 hours to about 10 hours, and reduced toxicity. In some cases, the reduced toxicity is at least 1-fold, 2-fold, 3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold, 10-fold, 20-fold, 30-fold, 50-fold, 100-fold, or more reduced compared to Aldesleukin. In some cases, the reduced toxicity is at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 200%, 300%, 400%, 500%, or more reduced compared to Aldesleukin.

[0151] In some embodiments, the IL-2 conjugate comprises a conjugated moiety, and the size (e.g., volume or length) of the conjugated moiety increases plasma stability but does not decrease efficacy. In some examples, the size of the conjugated moiety extends the plasma half-life for at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, or more. In some examples, the size of the conjugated moiety extends the plasma half-life for at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, or more. In some examples, the size of the conjugated moiety extends the plasma half-life from about 1 hour to about 18 hours, from about 1 hour to about 12 hours, from about 2 hours to about 10 hours, from about 2 hours to about 8 hours, from about 4 hours to about 18 hours, from about 4 hours to about 12 hours, from about 4 hours to about 10 hours, from about 4 hours to about 8 hours, from about 6 hours to about 18 hours, from about 6 hours to about 12 hours, from about 6 hours to about 10 hours, from about 6 hours to about 8 hours, from about 8 hours to about 18 hours, from about 8 hours to about 12 hours, or from about 8 hours to about 10 hours. In some examples, the size of the conjugated moiety decreases efficacy by 5%, 4%, 3%, 2%, less than 1%, or less compared to aldesleukin.

[0152] In some embodiments, the IL-2 conjugate comprises a conjugated moiety, and the size (e.g., volume or length) of the conjugated moiety increases plasma stability and efficacy. In some examples, the size of the conjugated moiety extends the plasma half-life for at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, or more. In some examples, the size of the conjugated moiety extends the plasma half-life for at least 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, or more. In some examples, the size of the conjugated moiety extends the plasma half-life from about 1 hour to about 18 hours, from about 1 hour to about 12 hours, from about 2 hours to about 10 hours, from about 2 hours to about 8 hours, from about 4 hours to about 18 hours, from about 4 hours to about 12 hours, from about 4 hours to about 10 hours, from about 4 hours to about 8 hours, from about 6 hours to about 18 hours, from about 6 hours to about 12 hours, from about 6 hours to about 10 hours, from about 6 hours to about 8 hours, from about 8 hours to about 18 hours, from about 8 hours to about 12 hours, or from about 8 hours to about 10 hours. In some examples, the size of the conjugated moiety further increases efficacy by 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, more than 200%, or more compared to aldesleuk...

Claims

1. An IL-2 conjugate comprising an IL-2 polypeptide, comprising an amino acid sequence having at least 90% sequence identity with SEQ ID NO: 3, wherein at least one amino acid residue has the structure of formula (I): 【Chemical 1】 (wherein: Z is CH 2 and Y is ​ is; Y is CH 2 and Z is [Chemical Formula 3] is; Z is CH 2 and Y is 【Chemical Formula 4】 is; or Y is CH 2 and Z is [Chemical Formula 5] is; W is a PEG group having a molecular weight selected from 5 kDa ± 15%, 10 kDa ± 15%, 15 kDa ± 15%, 20 kDa ± 15%, 25 kDa ± 15%, 30 kDa ± 15%, 35 kDa ± 15%, 40 kDa ± 15%, 45 kDa ± 15%, 50 kDa ± 15%, and 60 kDa ± 15%; X has the following structure: 【Chemical Formula 6】 has; X-1 represents the point of attachment to the previous amino acid residue; and X+1 represents the point of attachment to the subsequent amino acid residue) is replaced by, at least one amino acid residue is an amino acid position selected from F41, K42, E61 and P64, based on the amino acid position in SEQ ID NO: 3, The IL-2 conjugate is characterized in that it selectively expands CD4+ helper cells, CD8+ effector naive cells, CD8+ effector memory T cells, NK cells, NKT cells, or combinations thereof. The IL-2 conjugate described above.

2. An IL-2 conjugate comprising an IL-2 polypeptide, comprising an amino acid sequence having at least 90% sequence identity with SEQ ID NO: 3, wherein at least one amino acid residue has the structure of formula (I): [Chemical Formula 7] (wherein: Z is CH 2 and Y is [Chemical 8] is; Y is CH 2 and Z is 【Chemical Formula 9】 is; Z is CH 2 and Y is 【Chemical Formula 10】 is; or Y is CH 2 and Z is 【Chemical Formula 11】 is; W is a PEG group having a molecular weight selected from 5 kDa ± 15%, 10 kDa ± 15%, 15 kDa ± 15%, 20 kDa ± 15%, 25 kDa ± 15%, 30 kDa ± 15%, 35 kDa ± 15%, 40 kDa ± 15%, 45 kDa ± 15%, 50 kDa ± 15%, and 60 kDa ± 15%; X has the following structure: 【Chemical 12】 has; X-1 represents the point of attachment to the previous amino acid residue; and X+1 represents the point of attachment to the subsequent amino acid residue) is replaced by, at least one amino acid residue is an amino acid position selected from F41, K42, E61 and P64, based on the amino acid position in SEQ ID NO: 3, The IL-2 conjugate has a reduced binding affinity for IL-2Rα compared to that of the wild-type IL-2 polypeptide to IL-2Rα, and is characterized in that the binding to the IL-2Rβγ signaling complex is maintained. The IL-2 conjugate.

3. The IL-2 conjugate according to claim 1 or 2, wherein the IL-2 polypeptide comprises an amino acid sequence having 95% sequence identity with SEQ ID NO: 3, and at least one amino acid residue is replaced with the structure of formula (I).

4. The IL-2 conjugate according to claim 1 or 2, wherein the IL-2 polypeptide comprises an amino acid sequence having 97% sequence identity with SEQ ID NO: 3, and at least one amino acid residue is replaced with the structure of formula (I).

5. An IL-2 conjugate comprising an IL-2 polypeptide comprising the amino acid sequence of SEQ ID NO: 3, wherein at least one amino acid residue has the structure of formula (I): 【Chemical 13】 (wherein: Z is CH 2 and Y is 【Chemical 14】 is; Y is CH 2 and Z is 【Chemical Formula 15】 is; Z is CH 2 and Y is 【Chemical 16】 is; or Y is CH 2 and Z is 【Chemical 17】 is; W is a PEG group having a molecular weight selected from 5 kDa ± 15%, 10 kDa ± 15%, 15 kDa ± 15%, 20 kDa ± 15%, 25 kDa ± 15%, 30 kDa ± 15%, 35 kDa ± 15%, 40 kDa ± 15%, 45 kDa ± 15%, 50 kDa ± 15%, and 60 kDa ± 15%; X has the following structure: 【Chemical 18】 has; X-1 indicates the point of attachment to the previous amino acid residue; and X+1 indicates the point of attachment to the subsequent amino acid residue) is replaced with, The IL-2 conjugate, wherein at least one amino acid residue is an amino acid position selected from F41, K42, E61, and P64 based on the amino acid position in SEQ ID NO:

3.

6. The IL-2 conjugate according to any one of claims 1 to 5, wherein at least one amino acid residue is at the position of P64.

7. The IL-2 conjugate according to any one of claims 1 to 6, wherein the structure of formula (I) has the structure of formula (IV) or formula (V): 【Chemical 19】 The IL-2 conjugate according to any one of claims 1 to 6, which has the structure of.

8. The IL-2 conjugate according to any one of claims 1 to 7, wherein W is a PEG group having a molecular weight of 30 kDa ± 15%.

9. At least one amino acid residue is at the position of P64, and has the formula (XII) or formula (XIII): 【Chemical 20】 (wherein: n is -(OCH 2 CH 2 ) n -OCH 3 and is an integer such that it has a molecular weight of 5 kDa±15%, 10 kDa±15%, 15 kDa±15%, 20 kDa±15%, 25 kDa±15%, 30 kDa±15%, 35 kDa±15%, 40 kDa±15%, 45 kDa±15%, 50 kDa±15%, or 60 kDa±15%; and The wavy line indicates a covalent bond to each of the amino acid residue at the position immediately before the P64 within SEQ ID NO: 3 and the amino acid residue at the position immediately after the P64). is replaced by the structure of formula (I) having The IL-2 conjugate according to any one of claims 1 to 6. **Claim 10** n is a PEG group having the structure of -(OCH 2 CH 2 ), and is an integer such that it has a molecular weight of 30 kDa ± 15%, the IL-2 conjugate according to claim 9. n -OCH 3 ​ **Claim 11** The IL-2 conjugate according to any one of claims 1 to 10, which is a pharmaceutically acceptable salt, solvate or hydrate. **Claim 12** A pharmaceutical composition comprising the IL-2 conjugate according to any one of claims 1 to 11 and a pharmaceutically acceptable excipient. **Claim 13** A pharmaceutical composition comprising a mixture of the IL-2 conjugate according to any one of claims 9 to 11 and a pharmaceutically acceptable excipient, wherein the mixture comprises (i) an IL-2 conjugate in which at least one amino acid residue is replaced by the structure of formula (XII) at the position of P64, and (ii) an IL-2 conjugate in which at least one amino acid residue is replaced by the structure of formula (XIII) at the position of P64. **Claim 14** A pharmaceutical composition comprising a mixture of the IL-2 conjugate according to claim 7, 8 or 11 and a pharmaceutically acceptable excipient, wherein the mixture comprises (i) an IL-2 conjugate having the structure of formula (I) with the structure of formula (IV), and (ii) an IL-2 conjugate having the structure of formula (I) with the structure of formula (V). **Claim 15** The pharmaceutical composition according to any one of claims 12 to 14 for use in the treatment of cancer in a subject in need thereof. **Claim 16** The pharmaceutical composition according to claim 15, wherein the cancer is selected from renal cell carcinoma (RCC), melanoma, non-small cell lung cancer (NSCLC), head and neck squamous cell carcinoma (HNSCC), urothelial carcinoma (UC), Merkel cell carcinoma (MCC), ovarian cancer, gastric cancer, breast cancer, bladder cancer, bone cancer, brain cancer, colorectal cancer, esophageal cancer, eye cancer, head and neck cancer, kidney cancer, lung cancer, pancreatic cancer, prostate cancer, cutaneous squamous cell carcinoma (CSCC), and classical Hodgkin lymphoma (cHL). **Claim 17** A method for producing an IL-2 conjugate, having the following structure: **Claim 18** 【Chemical 21】 An IL-2 polypeptide, or a pharmaceutically acceptable salt, solvate or hydrate thereof, comprising a non-natural amino acid having, wherein the IL-2 polypeptide comprises an amino acid sequence having at least 90% sequence identity with SEQ ID NO: 3, position X indicates the position of the amino acid residue within SEQ ID NO: 3 at which the non-natural amino acid is substituted, position X is F41, K42, E61 or P64 based on the amino acid position within SEQ ID NO: 3, position X-1 indicates the point of attachment to the amino acid residue within SEQ ID NO: 3 preceding the non-natural amino acid, and position X+1 indicates the point of attachment to the amino acid residue within SEQ ID NO: 3 following the non-natural amino acid, and the wavy lines indicate covalent bonds to the amino acid residues at positions X-1 and X+1 within SEQ ID NO: 3, said IL-2 polypeptide, or a pharmaceutically acceptable salt, solvate or hydrate thereof, and Formula: 【Chemical 22】 (Wherein: n is an integer such that mPEG-DBCO comprises PEG having a molecular weight of 5 kDa ± 15%, 10 kDa ± 15%, 15 kDa Da ± 15%, 20 kDa ± 15%, 25 kDa ± 15%, 30 kDa ± 15%, 35 kDa ± 15%, 40 kDa ± 15%, 45 kDa ± 15%, 50 kDa ± 15%, or 60 kDa ± 15%) reacting with mPEG-DBCO of to form an IL-2 conjugate comprising, wherein the IL-2 conjugate is characterized by selectively expanding CD4+ helper cells, CD8+ effector naive cells, CD8+ effector memory T cells, NK cells, NKT cells, or combinations thereof, said method.

18. A method for producing an IL-2 conjugate, having the following structure: Formula: 【Chemical 23】 An IL-2 polypeptide, or a pharmaceutically acceptable salt, solvate or hydrate thereof, comprising a non-natural amino acid having the following, wherein the IL-2 polypeptide comprises an amino acid sequence having at least 90% sequence identity with SEQ ID NO: 3, position X indicates the position of the amino acid residue in SEQ ID NO: 3 substituted by the non-natural amino acid, position X is F41, K42, E61 or P64 based on the amino acid position in SEQ ID NO: 3, position X-1 indicates the point of attachment to the amino acid residue in SEQ ID NO: 3 preceding the non-natural amino acid, and position X+1 indicates the point of attachment to the amino acid residue in SEQ ID NO: 3 following the non-natural amino acid, and the wavy line indicates a covalent bond to the amino acid residue at each of position X-1 and position X+1 in SEQ ID NO: 3; said IL-2 polypeptide, or a pharmaceutically acceptable salt, solvate or hydrate thereof, and Formula: 【Chemical 24】 (wherein: n is an integer such that mPEG-DBCO comprises PEG having a molecular weight of 5 kDa ± 15%, 10 kDa ± 15%, 15 kDa ± 15%, 20 kDa ± 15%, 25 kDa ± 15%, 30 kDa ± 15%, 35 kDa ± 15%, 40 kDa ± 15%, 45 kDa ± 15%, 50 kDa ± 15%, or 60 kDa ± 15%) reacting with mPEG-DBCO of formula: to form an IL-2 conjugate comprising wherein said IL-2 conjugate has a reduced binding affinity for IL-2Rα compared to that of the wild-type IL-2 polypeptide for IL-2Rα, and binding to the IL-2Rβγ signaling complex is maintained. Claim 19 A method for producing an IL-2 conjugate, having the following structure: 【Chemical Formula 25】 An IL-2 polypeptide, or a pharmaceutically acceptable salt, solvate or hydrate thereof, comprising a non-natural amino acid having the following, wherein the IL-2 polypeptide has the amino acid sequence of SEQ ID NO: 3, wherein the non-natural amino acid substitutes for the amino acid residue in SEQ ID NO: 3 at position X of P64 based on the amino acid position in SEQ ID NO: 3, position X-1 indicates the point of attachment to the amino acid residue in SEQ ID NO: 3 preceding the non-natural amino acid, and position X+1 indicates the point of attachment to the amino acid residue in SEQ ID NO: 3 following the non-natural amino acid; said IL-2 polypeptide, or a pharmaceutically acceptable salt, solvate or hydrate thereof, and Formula: 【Chemical 26】 (wherein: n is an integer such that mPEG-DBCO contains PEG having a molecular weight of 30 kDa ± 15%) mPEG-DBCO of is reacted to form an IL-2 conjugate having a non-natural amino acid at the position of P64 (position X) based on the amino acid position in SEQ ID NO: 3, the non-natural amino acid is covalently bonded to mPEG, and the non-natural amino acids covalently bonded to the mPEG collectively have the formula (XII) or formula (XIII): 【Chemical 27】 (wherein: the wavy line indicates a covalent bond to the amino acid residue at position X-1 and position X+1 in SEQ ID NO: 3, respectively) The method having the structure of

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