Anti-CD45 antibodies and their conjugates

Abstract

Disclosed are anti-CD45 antibodies, antigen-binding fragments thereof, and antibody-drug conjugates (ADCs) that specifically bind to human CD45. Such antibodies and ADCs are useful in therapeutic methods (e.g., methods for depleting CD45+ cells from a patient). The compositions and methods described herein may be used to directly treat disorders, for example, by reducing the population of CD45+ cancer cells or autoimmune cells. The compositions and methods described herein may also be used to prepare patients for hematopoietic stem cell transplantation therapy and improve hematopoietic stem cell graft engraftment by selectively depleting endogenous CD45+ cells prior to the transplant procedure.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application is a continuation of U.S. Provisional Application No. 62 / 929,137, filed November 1, 2019; U.S. Provisional Application No. 62 / 929,194, filed November 1, 2019; U.S. Provisional Application No. 62 / 929,207, filed November 1, 2019; U.S. Provisional Application No. 62 / 929,288, filed November 1, 2019; U.S. Provisional Application No. 62 / 929,601 filed on November 1, 2019; U.S. Provisional Application No. 62 / 929,283 filed on November 1, 2019; U.S. Provisional Application No. 62 / 929,347 filed on November 1, 2019; U.S. Provisional Application No. 62 / 940,742 filed on November 26, 2019; U.S. Provisional Application No. 62 / 978,147 filed on February 18, 2020; U.S. Provisional Application No. 63 / 015,348 filed on April 24, 2020; U.S. Provisional Application No. 63 / 015,348 filed on June 30, 2020 This application claims priority to U.S. Provisional Application No. 63 / 046,046, filed June 30, 2020; U.S. Provisional Application No. 63 / 046,164, filed September 29, 2020; and U.S. Provisional Application No. 63 / 084,903, filed September 29, 2020. The entire contents of each of the foregoing priority applications are incorporated by reference into this application.

[0002] [Array List] This application contains a Sequence Listing which has been submitted electronically in ASCII format, the entirety of which is as follows: The ASCII copy, created on October 29, 2020, is named 2020-10-29_M103034 1525WO_SL_ST25.txt and is 233 kilobytes in size. .

[0003] [Technical field] This application relates to anti-CD45 antibodies, antigen-binding fragments thereof, and antibody-drug conjugates thereof. The present application also describes an anti-CD45 antibody, an antigen-binding fragment thereof, or an antibody thereof. administering a conjugate of an antibody, its antigen-binding fragment, or an antibody-drug conjugate (ADC) to treat patients suffering from various pathological conditions (e.g., blood diseases, metabolic disorders, cancer, and autoimmune diseases, etc.), wherein the antibody, its antigen-binding fragment, or ADC is capable of binding CD45 on target cells (e.g., hematopoietic stem cells, immune cells, or other types of cancer) is also described. BACKGROUND OF THE INVENTION

[0004] CD45 (also known as protein tyrosine phosphatase, receptor type C (PTPRC)) is an enzyme encoded by the PTPRC gene in humans (Kaplan et al., PNAS 87:7000-7004 (1990)). CD45 is a member of the protein tyrosine phosphatase family, which includes signaling molecules that regulate various cellular processes such as cell proliferation, differentiation, the mitotic cycle, and oncogenic transformation. CD45 contains an extracellular domain, a single transmembrane segment, and two tandem cytoplasmic catalytic domains and thus belongs to the receptor type PTP family. CD45 is a type I transmembrane protein that exists as various isoforms on differentiated hematopoietic cells (excluding erythrocytes and plasma cells) (Holmes, Immunology 117:145-55 (2006)). CD45 has been shown to be a regulator of T- and B-cell antigen receptor signaling. CD45 functions by directly interacting (a form of co-stimulation) with components of the antigen receptor complex via its extracellular domain or by activating various Src family kinases essential for antigen receptor signaling via its cytoplasmic domain. CD45 also suppresses JAK kinases and thus negatively regulates cytokine receptor signaling. ​​​​​​​​It also functions as a nodal factor.

[0005] CD45 is present on the surface of hematopoietic cells including hematopoietic stem cells (HSCs), leukocytes, and osteoclasts of hematopoietic origin (Shivtiel et al., J Exp Med 205:2381 (2008)). In humans, deletion mutations within CD45 are associated with severe immunodeficiency. This is mainly due to the absence of CD45 on T cells (CD45 is typically abundant on T cells and is required to regulate SFK activity during antigen responses). CD45-deficient (CD45 - / - ) mouse bone marrow contains a normal number of hematopoietic cells, but the number of the most primitive HSCs is reduced, and their ability to be mobilized in response to G-CSF is impaired. In part, this defect is specific to the HSCs; without downregulation of SFK activity via CD45, integrin-mediated adhesion is increased, and the HSCs are more likely to remain in the stem cell niche. CD45 HSCs are also deficient in G-CSF-stimulated mobilization and homing to the chemokine CXCL12 / SDF-1, which has an adverse effect on post-transplant cell engraftment. - / - These defects can be restored by supplementing with an SFK inhibitor. This indicates that this role is normally performed by CD45. Similarly, recipients of CD45 also show deficiencies in the engraftment of normal HSCs and subsequent mobilization, indicating the role of CD45 in the stem cell niche and in HSCs (Shivtiel et al., J - / - Exp Med 205:2381 (2008)). Despite advances in medical technology, there is still a need to treat disorders of the hematopoietic system, particularly certain blood cell diseases, metabolic disorders, cancers, and autoimmune conditions. While hematopoietic stem cells (HSCs) have great therapeutic potential, limitations in their clinical use

[0006] remain. The world has been faced with the difficulty of ensuring engraftment of HSC grafts in a host. In particular, hematopoietic stem cell therapies that include antibodies targeting cell surface antigens on endogenous HSCs can induce unwanted immune stimulatory and effector functions that interfere with engraftment of exogenous HSC grafts. CD45, for example, is expressed on HSCs and on leukocytes, and thus serves as a target for therapies such as conditioning therapies, immune reset, and treatment of diseases. SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0007] Given the important role of CD45 in cell biology, anti-CD45 antibodies, and fragments thereof are needed. The present application describes anti-CD45 antibodies, antigen-binding fragments thereof, and antibody drug conjugates (ADCs). The anti-CD45 antibodies, antigen-binding fragments thereof, and antibody drug conjugates (ADCs) described herein can bind to hematopoietic stem cells (HSCs) and are useful, for example, as conditioning agents for HSC transplantation. In particular, the anti-CD45 antibodies, antigen-binding fragments thereof, and ADCs described herein can be used to specifically reduce, for example, host HSCs, immune cells (e.g., leukocytes), or disease-causing cells. Furthermore, the anti-CD45 antibodies, antigen-binding fragments thereof, and ADCs described herein can be used to treat patients with leukemia or lymphoma or to treat patients with autoimmune diseases such as multiple sclerosis and scleroderma. The anti-CD45 antibodies, antigen-binding fragments thereof, and ADCs described herein preserve the multi-potency and hematopoietic functionality of these cells after transplantation and exogenous Meet the requirements of compositions and methods for promoting engraftment of sex hematopoietic stem cell grafts.

Means for Solving the Problems

[0008] In a first aspect, the present invention provides an isolated anti-CD45 antibody, or an antigen-binding portion thereof, comprising: (a) A CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 2, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 3, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 4, in a heavy chain variable region; and a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 6, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 7, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 8, in a light chain variable region; (b) A CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 12, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 13, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 14, in a heavy chain variable region; and a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 16, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 17, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 18, in a light chain variable region; (c) A CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 22, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 23, and a CDR24 in SEQ ID NO: ​A heavy chain variable region comprising a CDR3 domain containing the recited amino acid sequence; and a light chain variable region comprising a CDR1 domain containing the amino acid sequence set forth in SEQ ID NO: 26, a CDR2 domain containing the amino acid sequence set forth in SEQ ID NO: 27, and a CDR3 domain containing the amino acid sequence set forth in SEQ ID NO: 28; (d) A CDR1 domain containing the amino acid sequence set forth in SEQ ID NO: 32, a CDR2 domain containing the amino acid sequence set forth in SEQ ID NO: 33, and A heavy chain variable region comprising a CDR3 domain containing the recited amino acid sequence; and a light chain variable region comprising a CDR1 domain containing the amino acid sequence set forth in SEQ ID NO: 36, a CDR2 domain containing the amino acid sequence set forth in SEQ ID NO: 37, and a CDR3 domain containing the amino acid sequence set forth in SEQ ID NO: 38; (e) A CDR1 domain containing the amino acid sequence set forth in SEQ ID NO: 42, a CDR2 domain containing the amino acid sequence set forth in SEQ ID NO: 43, and A heavy chain variable region comprising a CDR3 domain containing the recited amino acid sequence; and a light chain variable region comprising a CDR1 domain containing the amino acid sequence set forth in SEQ ID NO: 46, a CDR2 domain containing the amino acid sequence set forth in SEQ ID NO: 47, and a CDR3 domain containing the amino acid sequence set forth in SEQ ID NO: 48; (f) A CDR1 domain containing the amino acid sequence set forth in SEQ ID NO: 52, a CDR2 domain containing the amino acid sequence set forth in SEQ ID NO: 53, and A heavy chain variable region comprising a CDR3 domain comprising the recited amino acid sequence; and a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 56, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 57, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 58, a light chain variable region; (g) A CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 62, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 63, and A heavy chain variable region comprising a CDR3 domain comprising the recited amino acid sequence; and SEQ ID NO: A CDR1 domain comprising the amino acid sequence set forth in 66, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 67, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 68, a light chain variable region; (h) A CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 72, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 73, and A heavy chain variable region comprising a CDR3 domain comprising the recited amino acid sequence; and a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 76, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 77, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 78, a light chain variable region; (i) A CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 82, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 83, and A heavy chain variable region comprising a CDR3 domain comprising the recited amino acid sequence; and a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 86, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 87, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 88, a light chain variable region; or, (j) A CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 92, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 93, and a CDR3 domain comprising the recited amino acid sequence, a heavy chain variable region; and a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 96, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 97, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 98, a light chain variable region, is provided.

[0009] In another aspect, the present application provides an isolated anti-CD45 antibody, or an antigen-binding portion thereof, comprising: subunits: A CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 119, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 120, and a CDR3 domain comprising the recited amino acid sequence, a heavy chain variable region; and a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 122, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 123, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 124, a light chain variable region comprising a CDR3 domain, is provided.

[0010] In another aspect, the present invention provides an isolated anti-CD45 antibody, or an antigen-binding portion thereof, comprising: Score: (a) A heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 1, and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 5; (b) A heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 11, and the light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 15; (c) A heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 21, and the light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 25; (d) A heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 31, and the light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 35; (e) A heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 41, and the light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 45; (f) A heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 51, and the light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 55; (g) A heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 61, and the light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 65; (h) A heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 71, and the light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 75; (i) A heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 81, and the light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 85; or, (j) Heavy chain variable region comprising the amino acid sequence set forth in Sequence No. (SEQ ID NO): 91, and Sequence No. (SEQ ID NO): light chain variable region comprising the amino acid sequence set forth in 95, is provided.

[0011] In some embodiments of the above aspect, the isolated anti-CD45 antibody, or its antigen-binding portion comprises an Fc region. In certain embodiments, the Fc region is a human IgG1 Fc region, or is a human IgG4 Fc region.

[0012] In some embodiments, the antibody is a monoclonal antibody.

[0013] In some embodiments, the antibody is an intact antibody comprising a constant region.

[0014] In some embodiments, the antibody is an IgG. In certain embodiments, the IgG is IgG1 or IgG4.

[0015] In some embodiments of the above aspect, the antibody comprises a constant region, wherein the constant region is L234A, L235A, D265C, H310A, and H435A (numbering according to EU index) selected from the group consisting of at least 1, at least 2, at least 3, at least 4, or at least 5, amino acid substitutions. In certain embodiments, the constant region comprises the amino acid substitutions L234A, L235A and D265C (numbering according to EU index).

[0016] In some embodiments, the isolated anti-CD45 antibody of the present disclosure comprises a constant region, wherein the constant region comprises the following, (a) The heavy chain amino acid sequence set forth in SEQ ID NO: 102, SEQ ID NO: 103, SEQ ID NO: 104, SEQ ID NO: 105, or SEQ ID NO: 106; and, (b) The light chain amino acid sequence set forth in SEQ ID NO: 101.

[0017] In another aspect, the invention provides an isolated anti-CD45 antibody comprising: (a) The heavy chain amino acid sequence set forth in SEQ ID NO: 9 and the light chain amino acid sequence set forth in SEQ ID NO: 10; (b) The heavy chain amino acid sequence set forth in SEQ ID NO: 19 and the light chain amino acid sequence set forth in SEQ ID NO: 20; (c) The heavy chain amino acid sequence set forth in SEQ ID NO: 29 and the light chain amino acid sequence set forth in SEQ ID NO: 30; (d) The heavy chain amino acid sequence set forth in SEQ ID NO: 39 and the light chain amino acid sequence set forth in SEQ ID NO: 40; (e) The heavy chain amino acid sequence set forth in SEQ ID NO: 49 and the light chain amino acid sequence set forth in SEQ ID NO: 50; (f) The heavy chain amino acid sequence set forth in SEQ ID NO: 59 and the light chain amino acid sequence set forth in SEQ ID NO: 60; (g) The heavy chain amino acid sequence set forth in SEQ ID NO: 69 and the light chain amino acid sequence set forth in SEQ ID NO: 70; (h) The heavy chain amino acid sequence set forth in SEQ ID NO: 79 and the light chain amino acid sequence set forth in SEQ ID NO: 80; (i) The heavy chain amino acid sequence set forth in SEQ ID NO: 89 and the light chain amino acid sequence set forth in SEQ ID NO: 90; or, (j) The heavy chain amino acid sequence set forth in SEQ ID NO: 99, and the light chain amino acid sequence set forth in SEQ ID NO: 100, are provided.

[0018] In another aspect, the present invention an isolated anti-CD45 antibody that specifically binds to human CD45 with an epitope located within CD45 fragment 1 (SEQ ID NO: 114), CD45 fragment 2 (SEQ ID NO: 115), CD45 fragment 3 (SEQ ID NO: 116), CD45 fragment 4 (SEQ ID NO: 117), and / or CD45 fragment 5 (SEQ ID NO: 118 ), or an antigen-binding portion thereof, is provided. In some embodiments of the above aspect, the isolated anti-CD45 antibody, or an antigen-binding

[0019] portion thereof, is (a) an epitope of human CD45 located within CD45 fragment 2 and an epitope of human CD45 located within fragment 4 ; (b) an epitope of human CD45 located within CD45 fragment 1 and an epitope of human CD45 located within CD45 fragment 3; or, (c) an epitope of human CD45 located within CD45 fragment 5, specifically binds to.

[0020] In some embodiments, the isolated anti-CD45 antibody, or an antigen-binding portion thereof, (a) one or more residues selected from the group consisting of 405T, 407K, 419Y, 425K, 481R, 505R, and 509H in human CD45 (numbered with reference to SEQ ID NO: 113); or, In some embodiments, the isolated anti-CD45 antibody, or an antigen-binding portion thereof, (b) One or more residues selected from the group consisting of 486R, 493Y, and 502T in human CD45 (numbered with reference to SEQ ID NO: 113), binds specifically to.

[0021] In some embodiments, the isolated anti-CD45 antibody, or antigen-binding portion thereof, of the present disclosure binds specifically to human CD45 and cross-reacts with cynomolgus CD45.

[0022] In some embodiments, the isolated anti-CD45 antibody, or antigen-binding portion thereof, of the present disclosure has a dissociation constant (K -2 from 1x10 -3 to 1x10 -3 to 1x10 -4 to 1x10 -4 to 1x10 -5 to 1x10 -5 to 1x10 -6 to 1x10 -6 to 1x10 -7 to 1x10 -7 to 1x10 -8 D), and binds to human CD45. OFF )

[0023] In some embodiments, the isolated anti-CD45 antibody, or antigen-binding portion thereof, of the present disclosure has a K D of about 100 nM or less, about 90 nM or less, about 80 nM or less, about 70 nM or less, about 60 nM or less, about 50 nM or less, about 40 nM or less, about 30 nM or less, about 20 nM or less, about 10 nM or less, about 10 nM or less, or about 0.1 nM or less, when measured by bio-layer interferometry, and binds to human CD45 .

[0024] In another aspect, the present application provides a pharmaceutical composition comprising an antibody of the present invention, or an antigen-binding portion thereof, and a pharmaceutically acceptable carrier.

[0025] In another aspect, the present application provides an isolated nucleic acid comprising a nucleic acid sequence encoding an antibody of the present invention, or an antigen-binding portion thereof.

[0026] In another aspect, the present application provides a vector comprising the isolated nucleic acid of the present invention.

[0027] In another aspect, the present application provides a host cell comprising the isolated nucleic acid of the present invention, or the vector of the present invention. In some embodiments, the host cell is a Chinese Hamster Ovary (CHO) cell.

[0028] In another aspect, for use in reducing the population of CD45+ cells in a human patient, the present application provides a pharmaceutical composition comprising an antibody, or an antigen-binding portion, of any of the above aspects.

[0029] In another aspect, the present application provides a method for reducing the population of CD45+ cells in a human patient by administering to the human patient an antibody, or an antigen-binding portion thereof, of any of the above aspects. In some embodiments, the CD45+ cells are CD3+, CD19+, CD33+, CD34+, or CD45+ / B2M+. In other embodiments, the CD45+ cells are hematopoietic stem cells (HSCs). In still other embodiments, the CD45+ cells are HSCs, T cells, B cells, and / or myeloid cells.

[0030] In some embodiments of the above aspects, the CD45+ cells are reduced from the bone marrow of the patient and / or the peripheral blood of the patient.

[0031] In some embodiments of the above aspects, the patient requires hematopoietic stem cell transplantation. In some embodiments of the above aspects, the method further comprises administering to the patient a graft comprising hematopoietic stem cells. In certain embodiments, the graft is allogeneic. In alternative embodiments, the graft is autologous.

[0032] In another aspect, the present invention provides an antibody-drug conjugate (ADC) comprising an anti-CD45 antibody conjugated to a cytotoxin via a linker, or an antigen-binding portion thereof, wherein the anti-CD45 antibody, or an antigen-binding portion thereof, is an antibody of any of the above aspects, or an antigen-binding portion thereof.

[0033] In some embodiments of the above aspects, the antibody is conjugated to the cytotoxin via a cysteine residue in the constant domain of the antibody. In certain embodiments, the cysteine residue is introduced by an amino acid substitution in the constant region of the antibody. In specific embodiments, the amino acid substitution is D265C and / or V205C (EU numbering).

[0034] In some embodiments of the above aspects, the ADC has a drug-to-antibody ratio (DAR) of 1, 2, 3, 4, 5, 6, 7, or 8.

[0035] In some embodiments of the above aspects, the cytotoxin is an RNA polymerase inhibitor, a DNA intercalating agent, a DNA alkylating agent, a DNA cross-linking agent, an agent that disrupts protein synthesis, an agent that disrupts microtubule dynamics, or an agent that disrupts the spindle.

[0036] In some embodiments of the above aspects, the cytotoxin is amatoxin, anthracycline, auristatin, calicheamicin, debuganin, diphtheria toxin, duocarmycin, indolinobenzodiazepine (IGN), indolinobenzodiazepine dimer, i ​​Irinotecan, maytansine, maytansinoid, Pseudomonas exotoxin A, pyrrolobenzodiazepine (PBD), pyrrolobenzodiazepine dimer, saporin, and SN-38, selected from the group consisting of. In certain embodiments, the cytotoxin is an RNA polymerase inhibitor thereof. In certain embodiments, the RNA polymerase inhibitor is amatoxin. In some embodiments, the ADC is represented by the formula Ab-Z-L-Am, where Ab is an antibody or an antigen-binding portion thereof, L is a linker, Z is a chemical substructure,

[0037] and Am is amatoxin. In certain embodiments, Am-L-Z is represented by formula (I): Here, R1 is H, OH, OR

Chemical formula

[0038] In some embodiments, L-Z is

Chemical formula

Chemical formula

[0039] In some embodiments, the ADC is represented by one of the following: [Chemical formula] Here, X is -S-, -S(O)-, or -SO2-.

[0040] In some embodiments, the ADC has the following formula [Chemical formula] Here, Ab represents the position of attachment of the anti-CD45 antibody.

[0041] In other embodiments, the ADC has the following formula [Chemical formula] Here, Ab represents the position of attachment of the anti-CD45 antibody.

[0042] In alternative embodiments, the ADC has the following formula [Chemical formula] Here, Ab represents the position of attachment of the anti-CD45 antibody.

[0043] In other embodiments, the ADC has the following formula [Chemical formula] Here, Ab represents the position of attachment of the anti-CD45 antibody.

[0044] In still other embodiments, the ADC has the following formula:

Chemical formula

[0045] In some embodiments of the ADCs disclosed in the present application, the cytotoxin is pyrrolobenzodiazepine (PBD). In certain embodiments, the cytotoxin is a PBD dimer. In specific embodiments, the PBD dimer is represented by:

Chemical formula

[0046] In some embodiments of the ADCs disclosed in the present application, the linker is a peptide, oligosaccharide, -(CH2) -, -(CH2CH2O) p -, -(C=O)(CH2) q -, -(C=O)(CH2CH2O) r -, -(NHCH2CH2) t -, -(NHCH2CH2) u -, -PAB, Val-Cit-PAB, Val-Ala-PAB, Val-Lys(Ac)-PAB, Phe-Lys-PAB, Phe-Lys(Ac)-PAB, D-Val-Leu-Lys, Gly-Gly-Arg, Ala-Ala-Asn-PAB, or Ala-PAB, and includes one or more of them, where each of p, q, r, t, and u is an integer from 1 to 12 and is independently selected in each case.

[0047] ​​​In some embodiments of the ADCs disclosed in this application, the linker has the following structure as follows

Chemical Formula

[0048] In some embodiments of the ADCs disclosed in this application, the linker contains a reactive substituent Z' and has the following structure, combined as L-Z', before conjugating to the anti-CD45 antibody

Chemical Formula

[0049] In certain embodiments, R1 is CH3.

[0050] In some embodiments of the ADCs disclosed in this application, the cytotoxin-linker conjugate is tesirine, which contains a reactive substituent Z' and is combined as Cy-L-Z', before conjugating to the anti-CD45 antibody, and has the following structural formula

Chemical Formula

[0051] In some embodiments, the ADCs disclosed in this application have the structure

Chemical Formula

[0052] In some embodiments of the ADCs disclosed in this application, the cytotoxin is indolinobenz It is zoziazepine (IGN). In certain embodiments, the cytotoxin is an IGN dimer or an IGN pseudodimer.

[0053] In some embodiments, the cytotoxin is an IGN pseudodimer represented by:

Chemical formula

[0054] In some embodiments, the linker includes a dipeptide, a disulfide, a C1-C12 alkyl, a C=O, or a combination thereof.

[0055] In some embodiments, the linker is

Chemical formula

[0056] In some embodiments, the cytotoxin-linker conjugate includes a reactive substituent Z' before conjugating to the anti-CD45 antibody or its antigen-binding portion, and has the following structural formula combined as Cy-L-Z' Together with:

Chemical formula

[0057] In another aspect, the present invention provides a pharmaceutical composition comprising the ADC described above in this application and a pharmaceutically acceptable Carrier.

[0058] In another aspect, this application provides an effective amount of the anti-CD45 ADC described above in this application, A method for reducing the population of CD45+ cells in a human patient by administering to said patient. is provided.

[0059] In some embodiments of the above aspects, said CD45+ cells are CD3+, CD19+, CD33+, CD34+, or CD45+ / B2M+. In certain embodiments, said CD45+ cells are hematopoietic stem cells (HSCs). In other embodiments, said CD45+ cells are HSCs, T cells, B cells, and / or myeloid cells.

[0060] In some embodiments of the above aspects, said CD45+ cells are reduced from the bone marrow of said patient and / or the peripheral blood of said patient.

[0061] In some embodiments of the above aspects, said patient requires a hematopoietic stem cell transplantation.

[0062] In some embodiments of the above aspects, said method further comprises administering to said patient a graft comprising hematopoietic stem cells.

[0063] In another aspect, the present invention provides a method for reducing the population of CD45+ cells in a human patient in need of a hematopoietic stem cell (HSC) transplantation by administering to said patient the ADC described above in the present application prior to said patient receiving a graft comprising hematopoietic stem cells.

[0064] In another aspect, the present invention provides a method comprising: (a) administering to a human patient the ADC described above in the present application in an amount sufficient to reduce the population of CD45+ cells in said patient; and, (b) subsequently, administering to said patient a graft comprising hematopoietic stem cells. is provided.

[0065] In some embodiments, said graft is allogeneic. In other embodiments, said graft is autologous.

[0066] In some embodiments, a graft comprising hematopoietic stem cells is administered to the patient after the concentration of the ADC has been substantially cleared from the patient's blood.

[0067] In some embodiments, the hematopoietic stem cells or their progeny can localize to hematopoietic tissue and / or re-establish hematopoiesis after transplantation of the hematopoietic cells into the patient.

[0068] In some embodiments, when transplanted into the patient, the hematopoietic stem cells result in the restoration of a population of cells selected from the group consisting of megakaryocytes, thrombocytes, platelets, erythrocytes, mast cells, myeloblasts, basophils, neutrophils, eosinophils, microglia, granulocytes, monocytes, osteoclasts, antigen-presenting cells, macrophages, dendritic cells, natural killer cells, T-lymphocytes, and B-lymphocytes.

[0069] In some embodiments, the patient has a blood disorder, a metabolic disorder, cancer, or an autoimmune disorder, or a severe combined immunodeficiency disease (SCID). In certain embodiments, the patient has cancer. In specific embodiments, the cancer is a blood cancer. In specific embodiments, the blood cancer is acute myeloid leukemia, acute lymphoblastic leukemia, chronic myeloid leukemia, chronic lymphocytic leukemia, or multiple myeloma.

[0070] In certain embodiments, the patient has an autoimmune disorder. In specific embodiments, the autoimmune disorder is multiple sclerosis, type 1 diabetes, or scleroderma. In other embodiments the autoimmune disorder is multiple sclerosis, human systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disease, psoriasis treatment, type 1 diabetes, acute disseminated encephalomyelitis, Addison's disease, alopecia universalis Symptoms, ankylosing spondylitis, antiphospholipid antibody syndrome, aplastic anemia, autoimmune hemolytic anemia, autoimmune hepatitis, autoimmune inner ear disease, autoimmune lymphoproliferative syndrome, autoimmune oophoritis, Baló's disease, Behçet's disease, bullous pemphigoid, cardiomyopathy, Chagas disease, chronic fatigue immune dysfunction syndrome, chronic inflammatory demyelinating polyneuropathy, Crohn's disease, cicatricial pemphigoid, coeliac sprue-dermatitis herpetiformis, cold agglutinin disease, CREST syndrome, Degos disease, discoid lupus erythematosus, autonomic neuropathy, endometriosis, essential mixed cryoglobulinemia, fibromyalgia-fibromyositis, Goodpasture syndrome, Gra ves' disease, Guillain-Barré syndrome (GBS), Hashimoto's thyroiditis, hidradenitis suppurativa, idiopathic and / or acute thrombocytopenic purpura, idiopathic pulmonary fibrosis, IgA neuropathy, interstitial cystitis, juvenile arthritis, Kawasaki disease, lichen planus, Lyme disease, Ménière's disease, mixed connective tissue disease, myasthenia gravis, neuromyotonia, opsoclonus-myoclonus syndrome, optic neuritis, Ord's thyroiditis, pemphigus vulgaris, pernicious anemia, polychondritis, polymyositis and dermatomyositis, primary biliary cirrhosis, polyarteritis nodosa, polyendocrine syndrome, polymyalgia rheumatica, primary agammaglobulinemia, Raynaud's phenomenon, Reiter's syndrome, rheumatic fever, sarcoidosis, scleroderma, Sjögren's syndrome, stiff-person syndrome, Takayasu arteritis, temporal arteritis, ulcerative colitis, uveitis, vasculitis, vitiligo, vulvodynia, and Wegener's granulomatosis, selected from the group consisting of.

[0071] Furthermore, the present invention also includes the following embodiments:

[0072] In one embodiment, the present invention includes a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 2, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 3, and a ligand A variable region comprising a CDR3 domain comprising the amino acid sequence set forth in Sequence Number (SEQ ID NO): 4 comprising a heavy chain; and a CDR1 domain comprising the amino acid sequence set forth in Sequence Number (SEQ ID NO): 6 a CDR2 domain comprising the amino acid sequence set forth in Sequence Number (SEQ ID NO): 7, and a CDR3 domain comprising the amino acid sequence set forth in Sequence Number NO): 8, and providing an isolated anti-CD45 antibody, or an antigen-binding portion thereof, comprising a light chain comprising a variable region

[0073] In certain embodiments, the anti-CD45 antibody, or an antigen-binding portion thereof, comprises a heavy chain variable region comprising the amino acid sequence set forth in Sequence Number (SEQ ID NO): 1

[0074] In other embodiments, the anti-CD45 antibody, or an antigen-binding portion thereof, comprises a light chain variable region comprising the amino acid sequence set forth in Sequence Number (SEQ ID NO): 5

[0075] In certain embodiments, the anti-CD45 antibody, or an antigen-binding portion thereof, comprises a heavy chain variable region comprising the amino acid sequence set forth in Sequence Number (SEQ ID NO): 1; and a light chain variable region comprising the amino acid sequence set forth in Sequence Number (SEQ ID NO): 5

[0076] In certain embodiments, the anti-CD45 antibody, or an antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in Sequence Number (SEQ ID NO): 9

[0077] In certain embodiments, the anti-CD45 antibody, or an antigen-binding portion thereof, comprises a light chain comprising the amino acid sequence set forth in Sequence Number (SEQ ID NO): 10

[0078] ​In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 9; and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 10.

[0079] In one embodiment, the invention provides an isolated anti-CD45 antibody, or antigen-binding site thereof, comprising a heavy chain comprising a variable region comprising CDR1 having the amino acid sequence set forth in SEQ ID NO: 12, CDR2 having the amino acid sequence set forth in SEQ ID NO: 13, and CDR3 having the amino acid sequence set forth in SEQ ID NO: 14; and a light chain comprising a variable region comprising CDR1 having the amino acid sequence set forth in SEQ ID NO: 16, CDR2 having the amino acid sequence set forth in SEQ ID NO: 17, and CDR3 having the amino acid sequence set forth in SEQ ID NO: 18. , and provides the same.

[0080] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 11.

[0081] In other embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 15.

[0082] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 11; and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 15.

[0083] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 19.

[0084] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 20.

[0085] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 19; and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 20.

[0086] In one embodiment, the present invention provides an isolated anti-CD45 antibody, or antigen-binding site thereof, comprising a heavy chain comprising a variable region comprising CDR1 having the amino acid sequence set forth in SEQ ID NO: 22, CDR2 having the amino acid sequence set forth in SEQ ID NO: 23, and CDR3 having the amino acid sequence set forth in SEQ ID NO: 24, and a light chain comprising a variable region comprising CDR1 having the amino acid sequence set forth in SEQ ID NO: 26, CDR2 having the amino acid sequence set forth in SEQ ID NO: 27, and CDR3 having the amino acid sequence set forth in SEQ ID NO: 28.

[0087] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 21.

[0088] In other embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 25.

[0089] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 21; and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 25.​​​ a light chain variable region comprising the amino acid sequence set forth above.

[0090] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 29.

[0091] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 30.

[0092] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 29; and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 30. amino acid sequence, comprising.

[0093] In one embodiment, the present invention provides a CDR1 having the amino acid sequence set forth in SEQ ID NO: 32, a CDR2 having the amino acid sequence set forth in SEQ ID NO: 33, a CDR3 having the amino acid sequence set forth in SEQ ID NO: 34, a heavy chain comprising a variable region comprising, and a CDR1 having the amino acid sequence set forth in SEQ ID NO: 36, a CDR2 having the amino acid sequence set forth in SEQ ID NO: 37, a CDR3 having the amino acid sequence set forth in SEQ ID NO: 38, an isolated anti-CD45 antibody, or antigen-binding site thereof, comprising a light chain comprising a variable region comprising. thereof. is provided.

[0094] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 31.

[0095] In other embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 35.

[0096] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 31; and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 35.

[0097] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 39.

[0098] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 40.

[0099] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 39; and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 40.

[0100] In one embodiment, the invention provides an isolated anti-CD45 antibody, or antigen-binding site thereof, comprising a heavy chain comprising a variable region comprising CDR1 having the amino acid sequence set forth in SEQ ID NO: 42, CDR2 having the amino acid sequence set forth in SEQ ID NO: 43, and CDR3 having the amino acid sequence set forth in SEQ ID NO: 44; and a light chain comprising a variable region comprising CDR1 having the amino acid sequence set forth in SEQ ID NO: 46, CDR2 having the amino acid sequence set forth in SEQ ID NO: 47, and CDR3 having the amino acid sequence set forth in SEQ ID NO: 48. ​

[0101] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 41.

[0102] In other embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 45.

[0103] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 41; and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 45.

[0104] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 49.

[0105] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 50.

[0106] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 49; and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 50.

[0107] In one embodiment, the invention has an amino acid sequence set forth in SEQ ID NO: 52. A heavy chain comprising a variable region comprising a CDR1 having the amino acid sequence set forth in SEQ ID NO: 53, a CDR2 having the amino acid sequence set forth in SEQ ID NO: 54, and a CDR3 having the amino acid sequence set forth in SEQ ID NO: 54; and a light chain comprising a variable region comprising a CDR1 having the amino acid sequence set forth in SEQ ID NO: 56, a CDR2 having the amino acid sequence set forth in SEQ ID NO: 57, and a CDR3 having the amino acid sequence set forth in SEQ ID NO: 58, an isolated anti-CD45 antibody, or an antigen-binding site thereof is provided.

[0108] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 51.

[0109] In other embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 55.

[0110] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 51; and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 55.

[0111] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 59.

[0112] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 60.

[0113] ​In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 59; and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 60. It comprises a light chain comprising the amino acid sequence.

[0114] In one embodiment, the invention provides an isolated anti-CD45 antibody, or antigen-binding site thereof, comprising a heavy chain comprising a variable region comprising a CDR1 having the amino acid sequence set forth in SEQ ID NO: 62, a CDR2 having the amino acid sequence set forth in SEQ ID NO: 63, and a CDR3 having the amino acid sequence set forth in SEQ ID NO: 64; and a light chain comprising a variable region comprising a CDR1 having the amino acid sequence set forth in SEQ ID NO: 66, a CDR2 having the amino acid sequence set forth in SEQ ID NO: 67, and a CDR3 having the amino acid sequence set forth in SEQ ID NO: 68. is provided.

[0115] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 61.

[0116] In other embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 65.

[0117] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 61; and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 65. It comprises a light chain variable region comprising the amino acid sequence.

[0118] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 69.​

[0119] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 70.

[0120] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 69; and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 70.

[0121] In one embodiment, the invention provides an isolated anti-CD45 antibody, or antigen-binding site thereof, comprising a heavy chain comprising a variable region comprising CDR1 having the amino acid sequence set forth in SEQ ID NO: 72, CDR2 having the amino acid sequence set forth in SEQ ID NO: 73, and CDR3 having the amino acid sequence set forth in SEQ ID NO: 74, and a light chain comprising a variable region comprising CDR1 having the amino acid sequence set forth in SEQ ID NO: 76, CDR2 having the amino acid sequence set forth in SEQ ID NO: 77, and CDR3 having the amino acid sequence set forth in SEQ ID NO: 78.

[0122] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 71.

[0123] In other embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 75.

[0124] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises SEQ A heavy chain variable region comprising the amino acid sequence set forth in ID NO): 71; and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO): 75. In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO): 79.

[0125] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO): 80.

[0126] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO): 79; and a light chain comprising the amino acid sequence set forth in SEQ ID NO): 80.

[0127] In one embodiment, the invention provides an isolated anti-CD45 antibody, or antigen-binding site thereof, comprising a heavy chain comprising a variable region comprising CDR1 having the amino acid sequence set forth in SEQ ID NO): 82, CDR2 having the amino acid sequence set forth in SEQ ID NO): 83, and CDR3 having the amino acid sequence set forth in SEQ ID NO): 84, and a light chain comprising a variable region comprising CDR1 having the amino acid sequence set forth in SEQ ID NO): 86, CDR2 having the amino acid sequence set forth in SEQ ID NO): 87, and CDR3 having the amino acid sequence set forth in SEQ ID NO): 88. In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO): 81.

[0128]

[0129]

[0130] ​​​​In other embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 85.

[0131] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 81; and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 85.

[0132] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 89.

[0133] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 90.

[0134] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 89; and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 90.

[0135] In one embodiment, the invention provides an isolated anti-CD45 antibody, or antigen-binding site thereof, comprising a heavy chain comprising a variable region comprising CDR1 having the amino acid sequence set forth in SEQ ID NO: 92, CDR2 having the amino acid sequence set forth in SEQ ID NO: 93, and CDR3 having the amino acid sequence set forth in SEQ ID NO: 94, and a light chain comprising a variable region comprising CDR1 having the amino acid sequence set forth in SEQ ID NO: 96, CDR2 having the amino acid sequence set forth in SEQ ID NO: 97, and CDR3 having the amino acid sequence set forth in SEQ ID NO: 98. ​​​​

[0136] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 91. ID NO): 91.

[0137] In other embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 95.

[0138] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 91; and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 95. ID NO): 95.

[0139] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 99.

[0140] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 100.

[0141] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 99; and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 100.

[0142] In one embodiment, the anti-CD45 antibody described in this application is intact.

[0143] In certain embodiments, the anti-CD45 antibody fragment is selected from the group consisting of Fab, F(ab')2, and scFv. ID NO): 100.

[0144] In other embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, is a human antibody, or a binding fragment thereof.

[0145] In other embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises an Fc region comprising at least one amino acid substitution (such as H435 or I235 / H310 / H435 (EU numbering)). In one embodiment, the Fc region comprises an amino acid substitution at H435 (H435A (EU numbering)). In other embodiments, the Fc region comprises amino acid substitutions at I235 / H310 / H435, such as those described as I235A / H310A / H435A (EU numbering).

[0146] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, is an IgG, such as IgG1 or IgG4.

[0147] Antibody-drug conjugates (ADCs) comprising an anti-CD45 antibody (or antigen-binding fragment) are also described herein, wherein the antibody (or CD45-binding fragment) is conjugated to a cytotoxin via a linker.

[0148] In one embodiment, the anti-CD45 ADC comprises an anti-CD45 antibody conjugated to a cytotoxin that is an RNA polymerase inhibitor. In one embodiment, the RNA polymerase inhibitor is an amatoxin.

[0149] In one embodiment, the anti-CD45 ADC comprises a cytotoxin that is an amatoxin represented by formula (IA).

Chemical formula

[0150] In one embodiment, the anti-CD45 ADC has the following formula

Chemical formula

[0151] In one embodiment, the anti-CD45 ADC has the following formula

Chemical formula

[0152] In one embodiment, the anti-CD45 ADC comprises a cytotoxin that is amanitin (e.g., α-amanitin, β-amanitin, γ-amanitin, ε-amanitin, amanin, amanin amide, amanullin, amanullinic acid, and proamanullin).

[0153] In one embodiment, the anti-CD45 ADC is Pseudomonas exotoxin A, debuganin, diphtheria Ricin toxin, saporin, maytansine, maytansinoid, auristatin (e.g., MMAE , or MMAF), anthracycline, calicheamicin, irinotecan, SN-38, duocarmycin, pyrrolobenzodiazepine, pyrrolobenzodiazepine dimer, indolinobenzodiazepine, and indolinobenzodiazepine dimer, and comprises a cytotoxin selected from the group consisting of.

[0154] In one embodiment, the anti-CD45 ADC comprises a cytotoxin comprising a benzodiazepine moiety. In some embodiments, the anti-CD45 ADC comprises pyrrolobenzodiazepine ("PBD"). In some embodiments, the anti-CD45 ADC comprises indolinobenzodiazepine ("IGN").

[0155] In one embodiment, the anti-CD45 ADC comprises an anti-CD45 antibody conjugated to the toxin via a cysteine residue in the Fc domain of the antibody. In one embodiment, the cysteine residue is introduced via an amino acid substitution in the Fc domain of the antibody. In one embodiment, the amino acid substitution is D265C and / or V205C (EU numbering).

[0156] In certain embodiments, the anti-CD45 ADC has a drug to antibody ratio (DAR) of 1, 2, 3, 4, 5, 6, 7, or 8.

[0157] Also included in the present invention are pharmaceutical compositions comprising the anti-CD45 antibody or ADC described in the present application and a pharmaceutically acceptable carrier.

[0158] The anti-CD45 antibodies, fragments, and ADCs described in the present application may be used in a method of treatment in a human patient (e.g., but not limited to, allogeneic or autologous pre-transplant conditioning treatment).

[0159] In one embodiment, the present application discloses a method of reducing a population of hematopoietic stem cells (HSCs) in a human patient. The method comprises administering to the patient an effective amount of an anti-CD45 antibody, fragment, or ADC described in the present application. In certain embodiments, the method further comprises administering to the patient a graft comprising hematopoietic stem cells.

[0160] In other embodiments, the present application provides a method comprising administering to a human patient a graft (allogeneic or autologous) comprising hematopoietic stem cells, wherein the patient has previously been administered an anti-CD45 antibody, fragment, or ADC described in the present application in an amount sufficient to reduce the population of hematopoietic stem cells in the patient. In certain embodiments, the hematopoietic stem cells are CD45+ cells.

[0161] In yet other embodiments, an anti-CD45 antibody, fragment, or ADC described in the present application is used to treat a human patient having a blood disorder, metabolic disorder, cancer, or autoimmune disease, or severe combined immunodeficiency disease (SCID).

[0162] In one embodiment, an anti-CD45 antibody, fragment, or ADC described in the present application is administered to a human patient to treat leukemia in the human patient.

[0163] In other embodiments, the present application provides a method comprising administering to a human patient a graft comprising hematopoietic stem cells, wherein the patient has previously been administered an anti-CD45 antibody, fragment, or ADC described in the present application in an amount sufficient to reduce the population of hematopoietic stem cells in the patient. In one embodiment, the immune cells are CD137+, CD2+, or CD5+ cells. In other embodiments, the immune cells are T cells. BRIEF DESCRIPTION OF THE DRAWINGS ​​

[0164]

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Mode for Carrying Out the Invention

[0165] [Detailed Description] Disclosed herein are novel anti-CD45 antibodies, antigen-binding fragments thereof, and conjugates thereof (e.g., antibody-drug conjugates; ADCs) that are useful (e.g., they are useful because they cross-react between human CD45 and non-human primate CD45). Further, the anti-CD45 antibodies and fragments thereof described herein may be used as therapeutic agents. For example it may be useful to use the anti-CD45 antibodies and fragments thereof described herein as therapeutic agents. For example it may be beneficial to use anti-CD45 antibodies, fragments thereof, and anti-CD45 ADCs to reduce CD45+ cells in patients having conditions (e.g., but not limited to, leukemia and lymphoma) for which it is beneficial to reduce CD45+ cells, as well as in patients having autoimmune diseases such as multiple sclerosis and scleroderma. Also, the anti-hematopoietic cell antibodies (anti-CD45 antibodies) included herein are useful in hematopoietic stem cell therapy. For example, the antibodies or ADCs of the present application are useful in conditioning procedures to prepare a patient for receiving a graft comprising hematopoietic stem cells such procedures promote engraftment of hematopoietic stem cell transplants. According to the methods described herein, an anti-CD45 ADC, antibody, or antigen-binding fragment thereof that can bind to CD45 (e.g., CD45 expressed by hematopoietic cells [e.g., hematopoietic stem cells or mature immune cells (e.g , T cells)]) may be administered to a patient to condition the patient for hematopoietic stem cell transplantation therapy. As described herein, the anti-CD45 antibody may be covalently conjugated to a cytotoxin to form an antibody-drug conjugate (ADC) Administering an ADC that can bind to CD45 to a patient in need of hematopoietic stem cell transplantation therapy may, for example, selectively reduce endogenous hematopoietic stem cells, thereby creating a space to be filled by an exogenous hematopoietic stem cell graft which may promote engraftment of the hematopoietic stem cell graft

[0166] ​​​The following sections provide novel anti-CD45 antibodies and fragments thereof that have unique properties (e.g., cross-reactivity with both human CD45 and non-human primate CD45). The following sections also provide descriptions of anti-CD45 antibodies or conjugates thereof that may be administered to patients such as those suffering from cancer or autoimmune diseases, or patients in need of hematopoietic stem cell transplantation therapy, to facilitate engraftment of hematopoietic stem cell grafts, and methods of administering such therapeutic agents to patients (e.g., prior to hematopoietic stem cell transplantation).

[0167] Definition As used in this application, the term "about" refers to a value that is 5% higher or lower than the recited value. For example, the term "about 100 nM" indicates a range from 95 to 105 nM.

[0168] As used in this application, the term "allogeneic" is used to define a graft (e.g., a cell, tissue, or organ transplant) transplanted from a donor to a recipient in the context of transplantation, where the recipient is a different individual of the same species compared to the donor. to a recipient in the context of transplantation, where the recipient is a different individual of the same species compared to the donor. As used in this application, the term "autologous" refers to a transplant in the context of transplantation where the donor and recipient are the same individual, i.e., the same subject.

[0169] As used in this application, the term "heterologous" refers to a transplant in the context of transplantation where the donor and recipient are of different species. As used in this application, the term "autologous" refers to a transplant in the context of transplantation where the donor and recipient are the same individual, i.e., the same subject.

[0170] As used in this application, the term "heterologous" refers to a transplant in the context of transplantation where the donor and recipient are of different species. As used in this application, the term "heterologous" refers to a transplant in the context of transplantation where the donor and recipient are of different species.

[0171] As used herein, the term "immune cell" is intended to include, without limitation, cells that are of hematopoietic origin and play a role in the immune response. Immune cells include, without limitation, T cells and natural killer (NK) cells. Natural killer cells are well known in the art. In one embodiment, examples of natural killer cells include cell lines such as NK-92 cells. Further examples of NK cell lines include NKG, YT, NK-YS, HANK-1, YTS cells, and NKL cells. Immune cells may be allogeneic or autologous.

[0172] As used herein, the term "antibody" refers to an immunoglobulin molecule that specifically binds to a particular antigen or is immunologically reactive with a particular antigen. Antibodies include, without limitation, monoclonal antibodies, polyclonal antibodies, multispecific antibodies (e.g., bispecific antibodies), and antibody fragments (so long as they exhibit the desired antigen-binding activity).

[0173] Generally, an antibody comprises a heavy chain and a light chain that contain an antigen-binding region. Each heavy chain is composed of a heavy chain variable region (abbreviated as HCVR or VH herein) and a heavy chain constant region. The heavy chain constant region is composed of three domains (CH1, CH2, and CH3). Each light chain is composed of a light chain variable region (abbreviated as LCVR or VL herein) and a light chain constant region. The light chain constant region is composed of one domain (CL). The VH and VL regions can be further subdivided into regions of hypervariability (called complementarity determining regions (CDRs)), interspersed with more conserved regions (called framework regions (FRs)). Each VH and VL is composed of three CDRs and four FRs, with the amino terminus From the amino terminus towards the carboxyl terminus, arrange in the following order: FR1, CDR1, FR2, CDR2, FR3 , CDR3, FR4. The variable regions of the heavy and light chains include a binding domain that interacts with an antigen . The constant region of the antibody may mediate the binding of the immunoglobulin to host tissues or factors (e.g., various cells of the immune system (e.g., effector cells) and the first component of the classical complement system (C1q), etc.) .

[0174] As used in this application, the terms "antigen-binding fragment" or "antigen binding portion" of an antibody refer to one or more portions of the antibody that retain the ability to specifically bind to a target antigen. The antigen-binding function of an antibody can be performed by fragments of the full-length antibody . The antibody fragments can be, for example, Fab , F(ab')2, scFv, diabody, triabody, affibody, nanobody, aptamer -, or domain antibody. Examples of binding fragments included in the term "antigen-binding fragment" of an antibody include, but are not limited to, the following: (i) a monovalent fragment consisting of the Fab fragment, VL, VH, CL, and CH1 domains; (ii) an F(ab')2 fragment, a divalent fragment containing two Fab fragments linked by a disulfide bridge in the hinge region; (iii) an Fd fragment consisting of the VH and CH1 domains; (iv) an Fv fragment consisting of the VL and VH domains of a single arm of the antibody; (v) a dAb containing the VH and VL domains ; (vi) a dAb fragment consisting of the VH domain (see, e.g., Ward et al., Nature 341:544-546, 1989); (vii) a dAb consisting of the VH or VL domain; (viii) an isolated Complementary determining regions (CDRs); and (ix) combinations of two or more (e.g., two, three, four, five, or six) isolated CDRs optionally linked by a synthetic linker. Further, the two domains (VL and VH) of the Fv fragment are encoded by separate genes, but they can be linked by a linker using recombinant methods, resulting in a single protein chain (the VL and VH regions pair to form a monovalent molecule) ( known as a single-chain Fv (scFv); see, for example, Bird et al., Science 242:423-426, 1988 and Huston et al., Proc. Natl. Acad. Sci. USA 85:5879-5883, 1988). These antibody fragments can be obtained using conventional techniques known to those skilled in the art, and the fragments can be screened for utility in the same manner as intact antibodies. Antigen-binding fragments can be produced by recombinant DNA technology, enzymatic or chemical cleavage of intact immunoglobulins, or, in some cases, by chemical peptide synthesis procedures known in the art.

[0175] As used in this application, an "intact" or "full-length" antibody refers to an antibody having two heavy (H) chain polypeptides and two light (L) chain polypeptides interconnected by disulfide bonds. In certain embodiments, a toxin may be conjugated to an intact anti-CD45 antibody having the heavy chain amino acid sequence and / or light chain amino acid sequence described in this application .

[0176] As used herein, the term "monoclonal antibody" refers to an antibody obtained from a single clone, including any eukaryote, prokaryote, or phage clone, by any means available in the art or known, and is not limited to antibodies produced by hybridoma technology. Monoclonal antibodies useful in the present disclosure can be prepared using a variety of techniques known in the art, including using hybridoma, recombinant, and phage display technologies, or combinations thereof.

[0177] As used herein, the terms "Fc region", "Fc domain", and "IgG Fc domain" refer to the crystallizable fragment obtained by papain digestion of an IgG molecule, which is part of an immunoglobulin (e.g., an IgG molecule). The Fc region includes the C-terminal halves of the two heavy chains of the IgG molecule linked by disulfide bonds. This has no antigen-binding activity but includes sugar moieties and binding sites for Fc receptors, including complement and FcRn receptors (see below). For example, the Fc region includes the second constant domain CH2 (residues 231-340 of EU position in IgG1) and the third constant domain CH3 (residues 341-447 of EU position in human IgG1). As used herein, the Fc region includes the "lower hinge region" (residues 233-239 of EU position in IgG1). linked by disulfide bonds, including the C-terminal halves of the two heavy chains of the IgG molecule. This has no antigen-binding activity but includes sugar moieties and binding sites for Fc receptors, including complement and FcRn receptors (see below). For example, the Fc region includes the second constant domain CH2 (residues 231-340 of EU position in IgG1) and the third constant domain CH3 (residues 341-447 of EU position in human IgG1). As used herein, the Fc region includes the "lower hinge region" (residues 233-239 of EU position in IgG1). but includes sugar moieties and binding sites for Fc receptors, including complement and FcRn receptors (see below). For example, the Fc region includes the second constant domain CH2 (residues 231-340 of EU position in IgG1) and the third constant domain CH3 (residues 341-447 of EU position in human IgG1). As used herein, the Fc region includes the "lower hinge region" (residues 233-239 of EU position in IgG1).

[0178] Fc may refer to this isolated region, or this region in the context of an antibody, antibody fragment, or Fc fusion protein. Polymorphisms have been observed at many positions within the Fc domain, including but not limited to EU positions 270, 272, 312, 315, 356, and 358, etc. Thus, there may be slight differences between the sequences presented in this application and those known in the art. Thus, "wild-type IgG Fc domain" or "WT IgG Fc domain" refers to any naturally occurring IgG Fc region (i.e., any allele). The sequences of the heavy chains of human IgG1, IgG2, IgG3, and IgG4 can be found in many sequence databases, for example, in the Uniprot database (www.uniprot.org), with accession numbers P01857 (IGHG1_human), P01859 (IGHG2_human), P01860 (IGHG3_human), and P01861 (IGHG1_human), respectively. and can be found, for example, in the Uniprot database (www.uniprot.org), with accession numbers P01857 (IGHG1_human), P01859 (IGHG2_human), P01860 (IGHG3_human), and P01861 (IGHG1_human), respectively.

[0179] As used in this application, the terms "modified Fc region" or "variant Fc region" refer to an IgG Fc domain that contains one or more amino acid substitutions, deletions, insertions, or modifications introduced at any position within the Fc region. In certain embodiments, the variant IgG Fc domain contains one or more amino acid substitutions such that, compared to the wild-type Fc domain that does not contain said one or more amino acid substitutions, the binding affinity for Fc gamma R and / or C1q is reduced or eliminated. Furthermore, Fc binding interactions are essential for various effector functions and downstream signaling events, including but not limited to antibody dependent cell-mediated cytotoxicity (ADCC) and complement dependent cytotoxicity (CDC), etc. Thus, in certain embodiments, an antibody (e.g., an antibody, fusion protein, or conjugate) containing a variant Fc domain has one or more amino acids ​An amino acid sequence that does not contain substitutions, deletions, insertions, or modifications but is otherwise the same (e.g., an unmodified Fc region containing the amino acid residues that are naturally present at the corresponding positions in the Fc region ), may have an altered binding affinity for at least one or more Fc ligands (e.g., Fc gamma R) compared to the corresponding antibody.

[0180] Variant Fc domains are defined according to the amino acid modifications that compose them. For all amino acid substitutions discussed in this application with respect to the Fc region, the numbering always follows the EU index as in Kabat. Thus, for example, D265C is an Fc variant in which the aspartic acid (D) at EU position 265 is replaced with cysteine (C) in the parental Fc domain. It should be noted that the order in which the substitutions are made is arbitrary. The term "Fc gamma receptor" or "Fc gamma R" as used in this application refers to any member of the family of proteins that bind to the Fc region of IgG antibodies and are encoded by the Fc gamma R genes. In humans, this family includes, but is not limited to, Fc gamma RI (CD64) (e.g., isoforms Fc gamma RIa, Fc gamma RIb, and Fc gamma RIc, etc.); Fc gamma RII (CD32) (e.g., isoforms Fc gamma RIIa [e.g., allotypes H131 and R131], Fc gamma RIIb [e.g., Fc gamma RIIb-1 and Fc gamma RIIb-2], and Fc gamma RIIc, etc.); and Fc gamma RIII (CD16) (e.g., isoforms Fc gamma RIIIa [e.g., allotypes V158 and F158] and Fc gamma RIIIb [e.g., allotypes Fc gamma RIIIb-NA1 and Fc gamma RIIIb-NA2], and any undiscovered human Fc gamma R or isoform or allotype of Fc gamma R. The Fc gamma R can be any

[0181] In the context of this application, the term "Fc gamma receptor" or "Fc gamma R" refers to any member of the family of proteins that bind to the Fc region of IgG antibodies and are encoded by the Fc gamma R genes. In humans, this family includes, but is not limited to, Fc gamma RI (CD64) (e.g., isoforms Fc gamma RIa, Fc gamma RIb, and Fc gamma RIc, etc.); Fc gamma RII (CD32) (e.g., isoforms Fc gamma RIIa [e.g., allotypes H131 and R131], Fc gamma RIIb [e.g., Fc gamma RIIb-1 and Fc gamma RIIb-2], and Fc gamma RIIc, etc.); and Fc gamma RIII (CD16) (e.g., isoforms Fc gamma RIIIa [e.g., allotypes V158 and F158] and Fc gamma RIIIb [e.g., allotypes Fc gamma RIIIb-NA1 and Fc gamma RIIIb-NA2], and any undiscovered human Fc gamma R or isoform or allotype of Fc gamma R. The Fc gamma R can be any species or allotype or isoform of the Fc gamma R family. It may be derived from a living organism (e.g., but not limited to, human, mouse, rat, rabbit, and monkey, etc.). Mouse Fc gamma Rs include, but are not limited to, Fc gamma RI (CD64), Fc gamma RII (CD32), Fc gamma RIII (CD16), and Fc gamma RIII-2 (CD16-2), as well as any undiscovered mouse Fc gamma R or isoform or allotype of Fc gamma R.

[0182] When used in this application, the term "effector function" refers to a biochemical event resulting from the interaction between the Fc domain and the Fc receptor. Effector functions include, but are not limited to, ADCC, ADCP, and CDC. As used in this application, an "effector cell" refers to a cell of the immune system that expresses one or more Fc receptors and mediates one or more effector functions. Effector cells include, but are not limited to, monocytes, macrophages, neutrophils, dendritic cells, eosinophils, mast cells, platelets, B cells, large granular lymphocytes, Langerhans cells, natural killer (NK) cells, and gamma-delta T cells, and are derived from any living organism (e.g., but not limited to, human, mouse, rat, rabbit, and monkey).

[0183] When used in this application, the terms "silent", "silenced", or "silencing" refer to an antibody having a modified Fc region described in this application in which the binding to Fc gamma receptor (FcγR) is reduced compared to the binding to the FcγR of the same antibody containing an unmodified Fc region (e.g., when measured by BLI, e.g., when unmodified ), The decrease in binding to FcγR is at least 70%, at least 80%, at least 90%, at least 95%, at least 98%, at least 99%, or 100%, as compared to the binding of the same antibody containing the Fc region to FcγR. In some embodiments, the Fc-silenced antibody does not exhibit detectable binding to FcγR. The binding of an antibody having a modified Fc region to FcγR can be measured using various techniques known in the art (e.g., without limitation, equilibrium methods [e.g., enzyme-linked immunosorbent assay (ELISA); KinExA, Rathanaswami et al. Analytical Biochemistry, Vol. 373:52-60, 2008; radioimmunoassay (RIA)], or surface plasmon resonance assay or other mechanism-based assays [e.g., BIACORE.RTM analysis or Octet TM analysis (forteBIO)], as well as other methods [e.g., indirect binding assays, competitive binding assays, fluorescence resonance energy transfer (FRET), gel electrophoresis, and chromatography (e.g., gel filtration), etc.]). These and other methods may utilize labels on one or more components to be evaluated and / or may use various detection methods (e.g., without limitation, chromogenic labels, fluorescent labels, luminescent labels, or isotope labels, etc.). Regarding binding affinity and kinetics, it is described in detail in Paul, W. E., ed., Fundamental Immunology, 4th Ed., Lippincott-Raven, Philadelphia (1999) (which focuses on antibody-immunogen interactions). An example of a competitive binding assay is a radioimmunoassay that involves incubating a labeled antigen and an antibody of interest in the presence of increasing amounts of unlabeled antigen and detecting the antibody bound to the labeled antigen. From the data, the affinity and binding off-rate of the antibody of interest for a particular antigen may be determined by Scatchard plot analysis. Competition with a second antibody may also be measured using a radioimmunoassay. In this case, the antigen is incubated in the presence of an antibody of interest conjugated to a labeled compound and increasing amounts of an unlabeled second antibody.

[0184] As used in this application, the term "same antibody comprising an unmodified Fc region" refers to an antibody having the same amino acid sequence as a comparison Fc-modified antibody, but lacking the listed amino acid substitutions (e.g., D265C, H435A).

[0185] The term "antibody dependent cell-mediated cytotoxicity" or "ADCC" refers to a form of cytotoxicity in which a polypeptide peptide (e.g., an antibody) binds to an Fc receptor (FcR) present on certain cytotoxic cells (e.g., primarily NK cells, neutrophils, and macrophages), and these cytotoxic effector cells become specifically bound to "target cells" bearing the antigen, and subsequently damage the target cells with their cytotoxins (Hogarth et al., Nature review Drug Discovery 2012, 11:313). In addition to antibodies and their fragments, other polypeptides comprising an Fc domain that have the ability to specifically bind to antigen-bearing target cells (e.g., Fc fusion proteins and Fc conjugate proteins) are contemplated to effect cell-mediated cytotoxicity.

[0186] For simplicity, in this application, cell-mediated cytotoxicity resulting from the activity of a polypeptide containing an Fc domain is also referred to as ADCC activity. The ability of any particular polypeptide of the present disclosure to mediate lysis of target cells by ADCC can be assayed. To evaluate ADCC activity, a polypeptide of interest (e.g., an antibody) is added to target cells together with immune effector cells, resulting in lysis of said target cells. Cell lysis is generally detected by the release of a label (e.g., a radiolabeled substrate, a fluorescent dye, or a native intracellular protein) from the lysed cells. Effector cells useful in such assays include peripheral blood mononuclear cells (PBMCs) and natural killer (NK) cells. Specific examples of in vitro ADCC assays are described in Bruggemann et al., J. Exp. Med. 166:1351 (1987); Wilkinson et al., J. Immunol. Methods 258:183 (2001); Patel et al., J. Immunol. Methods 184:29 (1995). Alternatively, or additionally, the ADCC activity of an antibody of interest may be evaluated in vivo (e.g., in an animal model such as that disclosed in Clynes et al., Proc. Natl. Acad. Sci. USA 95:652 (1998)). When used in this application, the terms "conditioning" and "conditioned" refer to the process of preparing a patient in anticipation of receiving a graft (e.g., a graft containing hematopoietic stem cells). Such procedures promote engraftment of the hematopoietic stem cell graft (e.g., as inferred from the sustained increase in the amount of viable hematopoietic stem cells in a blood sample isolated from the patient after the conditioning procedure and subsequent hematopoietic stem cell transplantation). According to the methods described in this application, hematopoietic stem cells bind to CD45 expressed on - cells, and effector cells useful in such assays include peripheral blood mononuclear cells (PBMCs) and natural killer (NK) cells. Specific examples of in vitro ADCC assays are described in Bruggemann et al., J. Exp. Med. 166:1351 (1987); Wilkinson et al., J. Immunol. Methods 258:183 (2001); Patel et al., J. Immunol. Methods 184:29 (1995). Alternatively, or additionally, the ADCC activity of an antibody of interest may be evaluated in vivo (e.g., in an animal model such as that disclosed in Clynes et al., Proc. Natl. Acad. Sci. USA 95:652 (1998)). When used in this application, the terms "conditioning" and "conditioned" refer to the process of preparing a patient in anticipation of receiving a graft (e.g., a graft containing hematopoietic stem cells). Such procedures promote engraftment of the hematopoietic stem cell graft (e.g., as inferred from the sustained increase in the amount of viable hematopoietic stem cells in a blood sample isolated from the patient after the conditioning procedure and subsequent hematopoietic stem cell transplantation). According to the methods described in this application, hematopoietic stem cells bind to CD45 expressed on

[0187] When used in this application, the terms "conditioning" and "conditioned" refer to the process of preparing a patient in anticipation of receiving a graft (e.g., a graft containing hematopoietic stem cells). Such procedures promote engraftment of the hematopoietic stem cell graft (e.g., as inferred from the sustained increase in the amount of viable hematopoietic stem cells in a blood sample isolated from the patient after the conditioning procedure and subsequent hematopoietic stem cell transplantation). According to the methods described in this application, hematopoietic stem cells bind to CD45 expressed on - cells, and effector cells useful in such assays include peripheral blood mononuclear cells (PBMCs) and natural killer (NK) cells. Specific examples of in vitro ADCC assays are described in Bruggemann et al., J. Exp. Med. 166:1351 (1987); Wilkinson et al., J. Immunol. Methods 258:183 (2001); Patel et al., J. Immunol. Methods 184:29 (1995). Alternatively, or additionally, the ADCC activity of an antibody of interest may be evaluated in vivo (e.g., in an animal model such as that disclosed in Clynes et al., Proc. Natl. Acad. Sci. USA 95:652 (1998)). By administering an ADC, antibody, or antigen-binding fragment thereof that can bind, to a patient, hematopoiesis The patient may be conditioned in preparation for a hematopoietic stem cell transplantation therapy. As described in this application, the antibody may be conjugated covalently to a cytotoxin so as to form a drug-antibody conjugate. Administering to a patient in need of a hematopoietic stem cell transplantation therapy an antibody, antigen-binding fragment thereof, or ADC that can bind to the above antigen may for example, selectively reduce endogenous hematopoietic stem cells, thereby creating a space to be filled by an exogenous hematopoietic stem cell graft, and thus may promote engraftment of the hematopoietic stem cell graft.

[0188] As used in this application, the term "effective amount" or "therapeutically effective amount" refers to an amount of a therapeutic agent (e.g., anti-CD45 ADC) sufficient to achieve the desired result in the context of treating, preventing, ameliorating, or reducing the symptoms of a disease or disorder in a patient. For example , in some embodiments, a therapeutically effective amount of an anti-CD45 antibody or ADC is an amount sufficient to reduce or deplete the population of CD45+ cells in a patient. In other embodiments, a therapeutically effective amount of an anti-CD45 antibody or ADC is an amount sufficient to condition a patient in preparation for receiving a hematopoietic stem cell transplantation. In such embodiments, the therapeutically effective amount may be, for example, an amount sufficient to selectively reduce endogenous hematopoietic stem cells from the patient and / or an amount sufficient to promote engraftment of a hematopoietic stem cell graft in the patient. In other embodiments, a therapeutically effective amount of an anti-CD45 antibody or ADC is an amount sufficient to have an effect on an autoimmune disease or cancer in a human patient.

[0189] When used in this application, the term "half-life" refers to the time it takes for the plasma concentration of an antibody drug in a subject, e.g., a human subject, to decrease by half or 50% in the body. This 50% decrease in serum concentration reflects the amount of drug circulating.

[0190] When used in this application, the term "substantially cleared from the blood" refers to a point in time after administration of a therapeutic agent (e.g., an anti-CD45 antibody or an antigen-binding fragment thereof) to a patient, at which the concentration of the therapeutic agent in a blood sample isolated from the patient is such that the therapeutic agent cannot be detected by conventional methods (e.g., a point at which the therapeutic agent cannot be detected above the noise threshold of a device or assay used to detect the therapeutic agent), using various techniques known in the art, such as the ELISA-based detection assays described in this application, to detect an antibody, or antibody fragment. Additional assays that may be used to detect an antibody or antibody fragment include, among others, immunoprecipitation techniques and immunoblot assays, which are known in the art. When used in this application, the terms "specific binding" or "specifically binding" refer to the ability of an antibody to recognize and bind to a specific protein structure (epitope) rather than broadly to proteins. When an antibody is specific for epitope "A", in a reaction containing labeled "A" and the antibody, the amount of labeled A that binds to the antibody decreases if a molecule containing epitope A (or free unlabeled A) is present. For example, if the antibody is labeled it may be competitively displaced from the target by a corresponding unlabeled antibody.

[0191] When used in this application, the terms "specific binding" or "specifically binding" refer to the ability of an antibody to recognize and bind to a specific protein structure (epitope) rather than broadly to proteins. When an antibody is specific for epitope "A", in a reaction containing labeled "A" and the antibody, the amount of labeled A that binds to the antibody decreases if a molecule containing epitope A (or free unlabeled A) is present. For example, if the antibody is labeled it may be competitively displaced from the target by a corresponding unlabeled antibody. "binds specifically" to the target. In one embodiment, the anti- body binds to the target (e.g., CD45) with a K -4 D of at least about 10 -5 M, 10 -6 M, 10 -7 M, 10 -8 M, 10 -9 M, 10 -10 M, 10 -11 M, 10 -12 M, or less (less means a value less than 10 -12 , e.g., 10 -13 ), and specifically binds. In one embodiment, the term "specific binding to CD45" or "specifically binds to CD45" as used in this application D refers to an antibody that binds to CD45 and has a dissociation constant (K D) of 1.0×10 M or less when measured by surface plasmon resonance. In one embodiment, K -7 D (M) is measured by standard Bio-Layer Interferometry (BLI). In one embodiment, K D off (1 / s) is measured by standard Bio-Layer Interferometry (BLI). However, it should be understood that the antibody can specifically bind to two or more antigens with related sequences. For example, in one embodiment, the antibody is specific for human CD45 D . In one embodiment, K off off (1 / s) is measured by standard Bio-Layer Interferometry (BLI). It should be understood, however, that the antibody can specifically bind to two or more antigens with related sequences. For example, in one embodiment, the antibody is specific for human CD45 . For example, in one embodiment, the antibody is specific for human CD45 and may specifically bind to both human and non-human (e.g., mouse, cynomolgus monkey or non-human primate) orthologs. Thus, as used in this application, an antibody that "specifically binds to human CD45" binds to human CD45 (and, presumably, CD45 from one or more non-human species [e.g., cynomolgus monkeys, etc.]), but does not substantially bind to non-CD45 proteins is intended to refer to an antibody that does not bind. Preferably, the antibody has a K -7 of 1 x 10 D M or less, a K -8 of 5 x 10 D M or less, a K -8 of 3 x 10 D M or less, a K -8 of 1 x 10 D M or less, or a K -9 of 5 x 10 D M or less and binds to human CD45.

[0192] As used in this application, the term "human antibody" is intended to include antibodies having variable regions derived from human germline immunoglobulin sequences. In embodiments where the human antibody includes a constant region, the constant region may likewise be derived from a human germline immunoglobulin sequence. A human antibody may include amino acid residues not encoded by a human germline immunoglobulin sequence (e.g., mutations introduced by random or site-directed mutagenesis in vitro or mutations introduced by gene rearrangement or somatic mutation in vivo). However, as used in this application, the term "human antibody" is not intended to include antibodies in which CDR sequences derived from the germline of another mammalian species, such as a mouse, are transplanted onto a human framework sequence. Human antibodies may be produced in human cells (e.g., by recombinant expression), or by non-human animals or prokaryotic or eukaryotic cells capable of expressing a functionally rearranged human immunoglobulin (e.g., heavy and / or light chain) gene. A human antibody is In the case of a single-chain antibody, it may contain a linker peptide that is not found in natural human antibodies. For example, an Fv may contain a linker peptide such as from 2 to about 8 glycine or other amino acid residues, and the linker peptide links the variable region of the heavy chain and the variable region of the light chain. Human antibodies may be produced by various methods known in the art, including phage display methods using antibody libraries derived from human immunoglobulin sequences, or yeast display methods. Human antibodies may also be produced using transgenic mice that are unable to express functional endogenous immunoglobulins but can express human immunoglobulin genes (see, for example, PCT Publication Nos. WO 1998 / 24893; WO 1992 / 01047; WO 1996 / 34096; WO 1996 / 33735; U.S. Patent Nos. 5,413,923; 5,625,126; 5,633,425; 5,569,825; 5,661,016; 5,545,806; 5,814,318; 5,885,793; 5,916,771; and 5,939,598). Human antibodies may be made by various methods known in the art, including phage display methods using antibody libraries derived from human immunoglobulin sequences, or yeast display methods. Human antibodies may also be produced using transgenic mice that are unable to express functional endogenous immunoglobulins but can express human immunoglobulin genes (see, for example, PCT Publication Nos. WO 1998 / 24893; WO 1992 / 01047; WO 1996 / 34096; WO 1996 / 33735; U.S. Patent Nos. 5,413,923; 5,625,126; 5,633,425; 5,569,825; 5,661,016; 5,545,806; 5,814,318; 5,885,793; 5,916,771; and 5,939,598).

[0193] The term "chimeric antibody" is intended to refer to an antibody in which the variable region sequence is derived from one species and the constant region sequence is derived from another species (e.g., an antibody in which the variable region sequence is derived from a rat antibody and the constant region sequence is derived from a human antibody). The term "chimeric antibody" is intended to refer to an antibody in which the variable region sequence is derived from one species and the constant region sequence is derived from another species (e.g., an antibody in which the variable region sequence is derived from a rat antibody and the constant region sequence is derived from a human antibody).

[0194] A "humanized" form of a non-human (e.g., mouse or rat) antibody is an immunoglobulin that contains minimal sequences derived from non-human immunoglobulins. Generally, a humanized antibody contains substantially all of at least one, typically two, variable domains, where all or substantially all of the CDR regions correspond to those of the non-human immunoglobulin and all or substantially all of the FR regions are human. All are of human immunoglobulin sequences. A humanized antibody may also comprise all or a portion of an immunoglobulin constant region (Fc), typically a human immunoglobulin consensus sequence. Methods for humanizing antibodies are known in the art. See, e.g., Riechmann et al., 1988, Nature 332:323-7; U.S. Patents 5,530,101; 5,585,089; 5,693,761; 5,693,762; and 6,180,370 to Queen et al.; EP 239400; PCT Publication WO 91 / 09967; U.S. Patent 5,225,539; EP 592106; EP 519596; Padlan, 1991, Mol. Immunol., 28:489-498; Studnicka et al., 1994, Prot. Eng. 7:805-814; Roguska et al., 1994, Proc. Natl. Acad. Sci. 91:969-973; and U.S. Patent 5,565,332.

[0195] "Conservative sequence modifications" of the sequences set forth in the SEQ ID NOs described herein are also provided. Conservative sequence modifications include modifications of the nucleotide and amino acid sequences that do not abolish the binding of the antibody or its antigen-binding site, including the amino acid sequence encoded by the nucleotide sequence, provided against a cognate antigen (e.g., CD45). Such conservative sequence modifications include conservative nucleotide and amino acid substitutions, as well as nucleotide and amino acid additions and deletions. For example, modifications can be made by methods known in the art, such as site-directed mutagenesis and PCR-mediated mutagenesis. Conservative sequence modifications may be introduced into the SEQ ID NOs set forth in this application by routine techniques known in the art. Conservative sequence modifications include conservative amino acid substitutions, in which an amino acid residue is replaced with an amino acid residue having a similar side chain. Families of amino acid residues having similar side chains have been defined in the art. These families include those with basic side chains (e.g., lysine, arginine, histidine), acidic side chains (e.g., aspartic acid, glutamic acid), uncharged polar side chains (e.g., glycine, asparagine, glutamine, serine, threonine, tyrosine ine, cysteine, tryptophan), nonpolar side chains (e.g., alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine), beta-branched side chains (e.g., threonine, valine, isoleucine) and aromatic side chains (e.g., tyrosine, phenylalanine, tryptophan, histidine). Accordingly, predicted non-essential amino acid residues in the anti-CD73 antibody are preferably substituted with another amino acid residue from the same side chain family. Methods for identifying conservative substitutions of nucleotides and amino acids that do not lose antigen binding are well known in the art (e.g., Brummell et al., Biochem. 32:1180-1187 (1993); Kobayashi et al. Protein Eng. 12(10):879-884 (1999); and Burks et al. Proc. Natl. Acad. Sci. USA 94:412-417 (1997)).

[0196] As used in this application, the term "engraftment potential" refers to hematopoietic stem cells and It is used to refer to the ability of hematopoietic stem cells to re-seed into tissues, regardless of whether such cells are naturally circulating or provided by transplantation. The term encompasses all events surrounding or leading to engraftment, such as cell tissue homing and cell colony formation within the tissue of interest. The efficiency or rate of engraftment can be evaluated or quantified using any clinically acceptable parameter known to those skilled in the art, for example, evaluating the competitive repopulating unit (CRU); uptake or expression of markers in the tissue where the stem cells have homed, formed colonies, or engrafted; or evaluating the progression of the subject by disease progression, survival of hematopoietic stem cells and hematopoietic progenitor cells, or life extension of the recipient. Engraftment can also be determined by measuring the number of white blood cells in the peripheral blood during the post-transplant period. Engraftment can also be evaluated by measuring the recovery rate of bone marrow cells by donor cells in a bone marrow aspiration sample.

[0197] As used in this application, the term "hematopoietic stem cell" ("HSC") refers to an immature blood cell having the ability to self-renew and the ability to differentiate into mature blood cells including, but not limited to, granulocytes (e.g., myeloblasts, neutrophils, eosinophils, basophils), erythrocytes (e.g., reticulocytes, erythrocytes), thrombocytes (e.g., megakaryoblasts, platelet-producing megakaryocytes, platelets), monocytes (e.g., monocytes, macrophages), dendritic cells, microglia, osteoclasts, and lymphocytes (e.g., NK cells, B cells, and T cells). Such cells may include CD34 cells. CD34 + cells are immature cells that express the CD34 cell surface marker. In humans, CD34+ cells are thought to include a subpopulation of stem cells having the stem cell characteristics defined above, while in mice, HSCs are CD34-. Furthermore, HSCs + cells are immature cells that express the CD34 cell surface marker. In humans, CD34+ cells are thought to include a subpopulation of stem cells having the stem cell characteristics defined above, while in mice, HSCs are CD34-. Furthermore, HSCs cells are immature cells that express the CD34 cell surface marker. In humans, CD34+ cells are thought to include a subpopulation of stem cells having the stem cell characteristics defined above, while in mice, HSCs are CD34-. Furthermore, HSCs also refers to long-term repopulating HSCs (LT-HSCs) and short-term repopulating HSCs (ST-HSCs). LT-HSCs and ST-HSCs are distinguished based on their functional potential and the expression of cell surface markers. For example, human HSCs are CD34+, CD38-, CD45RA-, CD90+, CD49F+, and lin- (negative for mature lineage markers including CD2, CD3, CD4, CD7, CD8, CD10, CD11B, CD19, CD20, CD56, CD235A, etc.). In mice, bone marrow LT-HSCs are CD34-, Sca-1+, c-Kit+, CD135-, Slamf1 / CD150+, CD48-, and lin- (negative for mature lineage markers including Ter119, CD11b, Gr1, CD3, CD4, CD8, B220, IL7ra, etc.), while ST-HSCs are CD34+, Sca-1+, c-Kit+, CD135-, Slamf1 / CD150+, and lin- (negative for mature lineage markers including Ter119, CD11b, Gr1, CD3, CD4, CD8, B220, IL7ra, etc.). In addition, ST-HSCs are less quiescent and more proliferative than LT-HSCs under homeostatic conditions. However, LT-HSCs have a higher self-renewal capacity (i.e., LT-HSCs can survive throughout adulthood and be continuously transplanted through successive recipients ), while ST-HSCs have a limited self-renewal capacity (i.e., ST-HSCs can only survive for a limited period and cannot be continuously transplanted). Any of these HSCs can be used in the methods described in this application. ST-HSCs are particularly useful because they are highly proliferative and can therefore generate differentiated progeny more rapidly.

[0198] As used in this application, the term "functional potential of hematopoietic stem cells" means 1) multi-potency (which includes, but is not limited to, granulocytes [e.g., myeloblasts, neutrophils, eosinophils , basophils], erythrocytes [e.g., reticulocytes, red blood cells], platelets (thrombocytes) [e.g. then megakaryoblasts, platelet-producing megakaryocytes, platelets, monocytes [e.g., monocytes, macrophages], dendritic cells, microglia, osteoclasts, and lymphocytes [e.g., NK cells, T cells, and B cells], etc., which refers to the ability to differentiate into multiple diverse blood lineages) 2) self-renewal (which refers to the ability of hematopoietic stem cells to give rise to daughter cells with the same potential as the mother cell, and furthermore, this ability can occur repeatedly throughout the individual's lifespan without depletion), and 3) the ability of hematopoietic stem cells or their progeny to home to the hematopoietic stem cell niche and re-establish productive and sustained hematopoiesis when re-introduced into a transplant recipient, refer to the functional characteristics of hematopoietic stem cells. including, for example, monocytes, macrophages, dendritic cells, microglia, osteoclasts, and lymphocytes [e.g., NK cells, T cells, and B cells], etc., which refers to the ability to differentiate into multiple diverse blood lineages), 2) self-renewal (which refers to the ability of hematopoietic stem cells to give rise to daughter cells with the same potential as the mother cell, and furthermore, this ability can occur repeatedly throughout the individual's lifespan without depletion), and 3) the ability of hematopoietic stem cells or their progeny to home to the hematopoietic stem cell niche and re-establish productive and sustained hematopoiesis when re-introduced into a transplant recipient, refer to the functional characteristics of hematopoietic stem cells.

[0199] As used in this application, the terms "subject" and "patient" refer to a living being, such as a human, who is undergoing treatment for a specific disease or condition as described in this application. In some embodiments, the subject or patient referred to in the methods provided by this application is a human subject.

[0200] As used in this application, the term "recipient" refers to a patient who receives a graft, such as a graft containing a population of hematopoietic stem cells. The transplanted cells administered to the recipient may be, for example, autologous, syngeneic, or allogeneic cells. As used in this application, the term "recipient" refers to a patient who receives a graft, such as a graft containing a population of hematopoietic stem cells. The transplanted cells administered to the recipient may be, for example, autologous, syngeneic, or allogeneic cells.

[0201] As used in this application, the term "to treat" or "treatment" with respect to a disease refers to any improvement in any outcome related to the disease (e.g., Refers to a decrease in the incidence of disease and / or side effects that are by-products of alternative treatment modalities; although it is preferred, but not essential for the treatment act, to completely eradicate the disease. For example, treatment may refer to reducing the severity and / or frequency of disease symptoms, eliminating disease symptoms and / or the underlying causes of said symptoms, reducing the frequency or likelihood of disease symptoms and / or their underlying causes, and improving or repairing damage caused directly or indirectly by the disease. Beneficial or desired clinical outcomes include, but are not limited to, promoting the engraftment of exogenous hematopoietic cells in a patient after antibody conditioning therapy as described in this application and subsequent hematopoietic stem cell transplantation therapy. Further beneficial outcomes include an increase in the cell number or relative concentration of hematopoietic stem cells in patients in need of hematopoietic stem cell transplantation after conditioning therapy and subsequent administration of an exogenous hematopoietic stem cell graft to said patient. Beneficial outcomes of the therapy described in this application also include, after conditioning therapy and subsequent hematopoietic stem cell transplantation therapy, one or more of the cells (e.g., megakaryocytes, thrombocytes, platelets, red blood cells, mast cells Increased cell number or relative concentration of myeloblasts, basophils, neutrophils, eosinophils, microglial cells, granulocytes, monocytes, osteoclasts, antigen-presenting cells, macrophages, dendritic cells, natural killer cells, T lymphocytes, or B lymphocytes, etc., may also be included. Further beneficial results may include a decrease in the amount of cell populations that cause disease, such as cancer cells (e.g., CD45+ leukemia cells) or autoimmune cells (e.g., CD45+ autoimmune lymphocytes such as CD45+ T-cells expressing a T-cell receptor that cross-reacts with a self-antigen). As long as the method of the present invention is directed to preventing a disorder, it is understood that the term "prevent" does not require the complete prevention of the disease state. Rather, as used in this application, the term prevent means what a person skilled in the art can do, such as identifying a population susceptible to a disorder and administering the compound of the present invention prior to the onset of the disease. The term does not mean that the disease state is completely avoided.

[0202] As used in this application, a patient "in need of" a hematopoietic stem cell transplant includes patients showing a defect or deficiency in one or more blood cell types, as well as patients having a stem cell disorder, an autoimmune disease, cancer, or other pathological conditions described in this application. Hematopoietic stem cells generally can differentiate into a plurality of various blood lineages including 1) multi-potency, thus, although not limited to, granulocytes (e.g., myeloblasts, neutrophils, eosinophils, basophils), erythrocytes (e.g., reticulocytes, red blood cells), thrombocytes (e.g., megakaryoblasts, platelet-producing megakaryocytes, platelets), monocytes (e.g., monocytes, macrophages ), dendritic cells, microglia, osteoclasts, and lymphocytes (e.g., NK cells, B-cells, and T-cells), etc., 2) self-renewal, thus including, but not limited to, granulocytes (e.g., myeloblasts, neutrophils, eosinophils, which can give rise to daughter cells having the same potential as the mother cell and, 3) when reintroduced into a transplant recipient, home to the hematopoietic stem cell niche and have the ability to re-establish productive and sustained hematopoiesis. Thus, in one or more cell types of the hematopoietic lineage, there are defects or deficiencies in a patient, in vivo, to reconstitute a population of cells that are defective or deficient hematopoietic stem cells may be administered. For example, the patient may be suffering from cancer, and the deficiency may be caused by administering a chemotherapeutic agent that selectively or non-specifically reduces a population of cancerous cells or other agents. Further, or alternatively, the patient may be suffering from an abnormal hemoglobinopathy (e.g., non-malignant abnormal hemoglobinopathy) such as sickle cell anemia, thalassemia, Fanconi anemia, aplastic anemia, and Wiskott-Aldrich syndrome The subject may be suffering from severe combined immunodeficiency (ADA SCID), HIV / AIDS, metachromatic leukodystrophy, Diamond-Blackfan anemia, and Shwachman-Diamond syndrome The subject may be suffering from a genetic blood disorder (e.g., sickle cell anemia) or an autoimmune disease or be affected by it. Further, or alternatively, the subject may have or be affected by a malignant tumor such as neuroblastoma or blood cancer. For example, the subject may have leukemia, lymphoma, or myeloma. In some embodiments, the subject has acute myeloid leukemia, acute lymphoblastic leukemia, chronic myeloid leukemia, chronic lymphocytic leukemia, multiple myeloma, diffuse large B-cell lymphoma, or non-Hodgkin's lymphoma. In some embodiments, the subject has myelodysplastic syndrome. In some embodiments, the subject has an autoimmune disease such as scleroderma, multiple sclerosis, ulcerative colitis, Crohn's disease, type I diabetes, or another autoimmune disease described in the present application or In some embodiments, the subject has an autoimmune condition. In some embodiments, the subject requires chimeric antigen receptor T-cell (CART) therapy. In some embodiments, the subject has or is affected by a metabolic storage disorder. The subject is selected from the group consisting of glycogen storage disease, mucopolysaccharidosis, Gaucher's disease, Hurler's disease, sphingolipidosis, metachromatic leukodystrophy, or any other disease or disorder (but not limited to severe combined immunodeficiency, Wiskott-Aldrich syndrome, hyperimmunoglobulin M syndrome, Chediak-Higashi disease, hereditary lymphohistiocytosis, marble bone disease, osteogenesis imperfecta, storage diseases, thalassemia major, sickle cell disease, systemic sclerosis, systemic lupus erythematosus, multiple sclerosis, juvenile rheumatoid arthritis), and can benefit from the treatments and therapies disclosed in this application. is suffering from, or has been affected by, the diseases or disorders described in "Bone Marrow Transplantation for Non-Malignant disease", ASH Education Book, 1:319-338 (2000) (this disclosure relates to conditions that may be treated by prescribing hematopoietic stem cell transplantation therapy, and the whole of which is incorporated herein by reference). Further or alternatively, a patient who "requires" hematopoietic stem cell transplantation may be a patient with or without one of the aforementioned conditions (nevertheless, a decrease in the level of one or more endogenous cell types within the hematopoietic lineage such as megakaryocytes, thrombocytes, platelets, erythrocytes, mast cells, myeloblasts, basophils, neutrophils, eosinophils, microglia, granulocytes, monocytes, osteoclasts, antigen-presenting cells, macrophages, dendritic cells, natural killer cells, T-lymphocytes, and B-lymphocytes, etc. [e.g., a decrease compared to the level in a subject who is otherwise healthy]). Some of those skilled in the art can determine, for example, by procedures known in the art, particularly by flow cytometry and fluorescence-activated cell sorting (FACS) methods, the level of one or more of the aforementioned cell types or other blood cell types. For a subject who is healthy in other respects, it is possible to readily determine whether it is decreased.

[0203] As used in the present application, the phrase "stem cell disorder" broadly refers to any disease, disorder, or condition that can be treated or cured by conditioning the subject's target tissue and / or by removing the endogenous stem cell population in the target tissue (e.g., by removing the endogenous hematopoietic stem cell population or hematopoietic progenitor cell population from the subject's bone marrow tissue), and / or by engrafting or transplanting stem cells into the subject's target tissue. For example, type I diabetes has been shown to be cured by hematopoietic stem cell transplantation and can benefit from conditioning according to the compositions and methods described in the present application. Further disorders that can be treated using the compositions and methods described in the present application include, but are not limited to, sickle cell anemia, thalassemia, Fanconi anemia, aplastic anemia, Wiskott-Aldrich syndrome, ADA SCID, HIV / AIDS, metachromatic leukodystrophy, Diamond-Blackfan anemia, and Shwachman-Diamond syndrome. Further diseases that can be treated using the patient conditioning and / or hematopoietic stem cell transplantation methods described in the present application include genetic blood diseases (e.g., sickle cell anemia) and autoimmune diseases such as scleroderma, multiple sclerosis, ulcerative colitis, and Crohn's disease. Further diseases that can be treated using the conditioning and / or transplantation methods described in the present application include malignant tumors (e.g., neuroblastoma) or blood cancers (e.g., leukemia, lymphoma, and myeloma). For example, said cancers are acute myeloid population in the target tissue of the subject (for example, by removing the endogenous hematopoietic stem cell population or hematopoietic progenitor cell population from the bone marrow tissue of the subject), and / or by engrafting or transplanting stem cells into the target tissue of the subject. For example, type I diabetes has been shown to be cured by hematopoietic stem cell transplantation and can benefit from conditioning according to the compositions and methods described in this application. Further disorders that can be treated using the compositions and methods described in this application include, but are not limited to, sickle cell anemia, thalassemia, Fanconi anemia, aplastic anemia, Wiskott-Aldrich syndrome, ADA SCID, HIV / AIDS, metachromatic leukodystrophy, Diamond-Blackfan anemia, and Shwachman-Diamond syndrome. Further disorders that can benefit from conditioning according to the compositions and methods described in this application include, but are not limited to, sickle cell anemia, thalassemia, Fanconi anemia, aplastic anemia, Wiskott-Aldrich syndrome, ADA SCID, HIV / AIDS, metachromatic leukodystrophy, Diamond-Blackfan anemia, and Shwachman-Diamond syndrome. Further diseases that can be treated using the patient conditioning and / or hematopoietic stem cell transplantation methods described in this application include genetic blood diseases (e.g., sickle cell anemia) and autoimmune diseases such as scleroderma, multiple sclerosis, ulcerative colitis, and Crohn's disease. Further diseases that can be treated using the conditioning and / or transplantation methods described in this application include malignant tumors (e.g., neuroblastoma) or blood cancers (e.g., leukemia, lymphoma, and myeloma). For example, the cancers include acute myeloid leukemia, lymphoma, and myeloma). For example, the cancer is acute myeloid The tumor may be myeloid leukemia, acute lymphocytic leukemia, chronic myelogenous leukemia, chronic lymphocytic leukemia, multiple myeloma, diffuse large B-cell lymphoma, or non-Hodgkin's lymphoma. Additional diseases that can be treated include myelodysplastic syndromes. In some embodiments, the subject has or is affected by a metabolic storage disorder. For example, the subject has a metabolic disorder selected from the group consisting of glycogen storage disease, mucopolysaccharidosis, Gaucher disease, Hurler disease, sphingolipidosis, metachromatic leukodystrophy, or any other disease or disorder that can benefit from the treatments and therapies disclosed herein, including, but not limited to, severe combined immunodeficiency syndrome, Wiskott-Aldrich syndrome, hyperimmunoglobulinemia, and the like. IgM syndrome, Chediak-Higashi disease, hereditary lymphohistiocytosis, osteopetrosis, bone formation Deficiency, storage diseases, thalassemia major, sickle cell disease, systemic sclerosis, systemic lupus erythematosus, multiple sclerosis, juvenile rheumatoid arthritis, and "Bone Marrow Transplantation for Non-Malignant Disease," ASH Education Book , 1:319-338 (2000) (This disclosure is directed to a method for treating hematopoietic stem cell transplantation therapy. The patient may be suffering from or affected by a disease or disorder described in the National Institute of Infectious Diseases and Neurology (NIH) 2004 / 010092, which is incorporated by reference in its entirety into this application, and which relates to conditions that may be present in the patient.

[0204] As used in this application, the term "vector" refers to a plasmid, a DNA vector, a plasmid This includes nucleic acid vectors, such as RNA vectors, viruses, or other suitable replicons. The expression vectors described in the application may contain polynucleotide sequences and additional sequence elements used, for example, to express proteins and / or to integrate these polynucleotide sequences into the genome of mammalian cells. Certain vectors that can be used to express the antibodies and antibody fragments of the present invention include plasmids containing regulatory sequences such as a promoter region and enhancer that direct gene transcription. Other useful vectors for expressing antibodies and antibody fragments contain polynucleotide sequences that enhance the translation rate of these genes or improve the stability or cytoplasmic translocation of the mRNA resulting from gene transcription. These sequence elements may include, for example, 5' and 3' untranslated regions and polyadenylation signal sites that enable efficient transcription of the gene on the expression vector. The expression vectors described in this application may also contain a polynucleotide encoding a marker for selecting cells containing such vectors. Examples of suitable markers include genes encoding resistance to antibiotics such as ampicillin, chloramphenicol, kanamycin, and nourseothricin.

[0205] As used in this application, the terms "conjugate" or "antibody-drug conjugate" or "ADC" refer to an antibody conjugated to a cytotoxin or toxin and are used interchangeably throughout. In one embodiment, the ADC is formed by the chemical conjugation of a reactive functional group of one molecule, such as an antibody or an antigen-binding fragment thereof, with a suitable reactive functional group of another molecule, such as a cytotoxin described in this application. In some embodiments, non-limiting examples of cytotoxins that may be used in the conjugates provided by this application include small organic molecules (e.g., MW 1500 Da or less), biomolecules (e.g., proteins), drug-loaded nanoparticles, or radionuclides. The conjugate is between two molecules bound to each other (e.g., between the antibody and the cytotoxin It may contain a linker in between. Examples of linkers that can be used for conjugate formation include peptide-containing linkers (e.g., linkers containing natural or non-natural amino acids, such as D-amino acids). The linker may be prepared using various strategies described in this application and known in the art. Depending on the reactive components therein, the linker may be cleaved, for example, by enzymatic hydrolysis, photolysis, hydrolysis under acidic conditions, hydrolysis under basic conditions, oxidation, disulfide reduction, nucleophilic cleavage, or organometallic cleavage (see, for example, Leriche et al., Bioorg. Med. Chem., 20:571-582, 2012).

[0206] The terms "conjugate", "conjugate to", or "conjugate with" mean at least two molecules conjugated together When used, it refers to one molecule (e.g., an antibody) linked or conjugated to a second molecule (e.g., a toxin). Anti-CD45 antibodies and their fragments may be conjugated to other molecules (e.g., toxins, labeling agents [e.g., fluorescein or biotin], drug-loaded nanoparticles). The conjugated molecules may be conjugated via covalent or non-covalent interactions. In certain embodiments, an anti-CD45 antibody or its fragment is conjugated to a protein toxin to form a protein fusion body (e.g., an scFv-toxin chimera). In some embodiments, the conjugated molecules are non-covalently bound via the interaction between a first interaction moiety (e.g., biotin) and a second interaction moiety (e.g., streptavidin) bound to the conjugated molecule

[0207] ​​​As used in this application, "drug-to-antibody ratio" or "DAR" refers to the number of drugs (e.g., amatoxins) bound to the antibody of the conjugate. Depending on the number of conjugation sites on the antibody, higher loading numbers are also conceivable, but the DAR of an ADC can range from 1 to 8. In certain embodiments, the conjugate has a DAR of 1, 2, 3, 4, 5, 6, 7, or 8.

[0208] As used in this application, the term "microtubule-binding agent" refers to a compound that acts by disrupting the microtubule network that is essential for mitosis and interphase cell function in cells. Examples of microtubule-binding agents include, but are not limited to, maytasine, mayta nsinoids, and their derivatives (such as those described in this application or known in the art ), vinca alkaloids such as vinblastine, vinblastine sulfate, vincristine, vincristine sulfate, vindesine, and vinorelbine, taxanes such as docetaxel and paclitaxel, discodermolide, macrolides such as colchicine and epothilone chloride, and their derivatives (such as epothilone B or its derivatives).

[0209] As used in this application, the term "amatoxin" refers to a member of the amatoxin family of peptides produced by Amanita phalloides mushrooms, or a derivative thereof (e.g., a variant or derivative thereof that can inhibit RNA polymerase II activity). Amatoxins useful in combination with the compositions and methods described in this application include the compounds described in this application (e.g., α-amanitin, β-amanitin, γ-amanitin, ε-amanitin, amanine, amanine amide, amanullin, amanullinic acid, or proamanullin, etc.). As described in this application, amatoxins can be, for example, via a linker substructure (L) and may be conjugated to an antibody, or an antigen-binding fragment thereof (thereby forming an ADC). Exemplary methods of conjugating amatoxins and linkers useful in such processes are described below. Exemplary linker-containing amatoxins useful for conjugating to an antibody, or antigen-binding fragment, by the compositions and methods are also described in this application.

[0210] As used herein, the term "acyl" refers to -C(=O)R, where, as defined herein, R is hydrogen ("aldehyde"), C1-C 12 alkyl, C2-C 12 alkenyl, C2-C 12 alkynyl , C3-C7 carbocyclic, C6-C 20 aryl, 5-10 membered heteroaryl, or 5-10 membered heterocy clyl. Non-limiting examples include formyl, acetyl, propanoyl, benzoyl l, and acryloyl.

[0211] As used herein, the term "C1-C 12 alkyl" refers to a straight-chain or branched saturated hydrocarbon having from 1 to 12 carbon atoms. Typical C1-C 12 alkyl groups include, but are not limited to, -methyl, -ethyl, -n-propyl, -n-butyl, -n-pentyl, and -n-hexyl; while branched C1-C 12 alkyl includes, but is not limited to, -isopro pyl, -sec-butyl, -isobutyl, -tert-butyl, -isopentyl, and 2-methylbutyl are included. C1-C 12 alkyl groups may be unsubstituted or may be substituted.

[0212] As used herein, the term "alkenyl" refers to an unsaturated moiety having at least one site, i.e., a carbon-carbon, sp 2C2-C containing normal, secondary, or tertiary carbon atoms having a double bond 12 carbon refers to a hydrocarbon. Examples include, but are not limited to: ethylene or vinyl, -allyl, -1-butenyl, -2-butenyl, -isobutenylenyl, -1-pentenyl, -2-pentenyl, -3-methyl-1-butenyl, -2-methyl-2-butenyl, -2,3-dimethyl-2-butenyl, propenyl, isopropenyl, butenyl, tert-butenylenyl, hexenyl, etc. The alken yl group may be unsubstituted or may be substituted.

[0213] As used in this application, "alkynyl" refers to an unsaturated moiety having at least one site, i.e., a carbon-carbon, sp triple bond, and containing normal, secondary, or tertiary carbon atoms, C2-C 12 refers to a hydrocarbon. Examples include, but are not limited to: acetylene and propargyl, butynyl, pentynyl, hexynyl, etc. The alkynyl group may be unsubstituted or may be substituted.

[0214] As used in this application, "aryl" refers to a C6-C 20 carbon ring aromatic group. Examples of aryl groups include, but are not limited to: phenyl, naphthyl, and anthracenyl. The aryl group may be unsubstituted or may be substituted.

[0215] As used in this application, "arylalkyl" refers to an acyclic a where one of the hydrogen atoms attached to a carbon atom (typically a terminal or sp 3 carbon atom is substituted by an aryl radical Refers to a luquil radical. Typical arylalkyl groups include, but are not limited to, benzyl, 2-phenylethan-1-yl, 2-phenylethen-1-yl, naphthylmethyl, 2-naphthylethan-1-yl, 2-naphthylethen-1-yl, naphthobenzyl, 2-naphthophenylethan-1-yl, etc. The arylalkyl group contains 6 to 20 carbon atoms. For example, the alkyl portion of the arylalkyl group (such as an alkanil, alkenyl or alkynyl group, etc.) has 1 to 6 carbon atoms, and the aryl portion has 5 to 14 carbon atoms. The alkaryl group may be unsubstituted or may be substituted.

[0216] As used in this application, "cycloalkyl" refers to a saturated carbocyclic radical, which may be monocyclic or bicyclic. Examples of cycloalkyl groups include a ring having 3 to 7 carbon atoms as a monocyclic ring, or a ring having 7 to 12 carbon atoms as a bicyclic ring. Examples of monocyclic cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl. The cycloalkyl group may be unsubstituted or may be substituted.

[0217] As used in this application, "cycloalkenyl" refers to an unsaturated carbocyclic radical, which may be monocyclic or bicyclic. Examples of cycloalkenyl groups include a ring having 3 to 6 carbon atoms as a monocyclic ring, or a ring having 7 to 12 carbon atoms as a bicyclic ring. Examples of monocyclic cycloalkenyl groups include 1-cyclopent-1-enyl, 1-cyclopent-2-enyl, 1-cyclopent-3-enyl, 1-cyclohex-1-enyl, 1-cyclohex-2-enyl, and 1-cyclohex-3-enyl. The cycloalkenyl group may be unsubstituted, or may be substituted.

[0218] As used in this application, "heteroaralkyl" refers to a heteroaralkyl group containing a carbon atom (typically a terminal or sp 3 carbon source one of the hydrogen atoms bonded to the heteroaryl group is replaced by a heteroaryl radical, It refers to a cyclic alkyl radical. Typical heteroarylalkyl groups include, but are not limited to, 2-benzimidazolylmethyl, 2-furylethyl, and the like. The heteroarylalkyl group contains 6 to 20 carbon atoms, e.g., the heteroaryl The alkyl portion of the alkyl group (including alkanyl, alkenyl, or alkynyl groups) is 1 to 6 carbon atoms, and the heteroaryl portion is 5 to 14 carbon atoms. and 1 to 3 heteroatoms selected from N, O, P, and S. The heteroaryl portion of the heteroarylalkyl group can be a monocycle having 3 to 7 ring members (2 to 6 carbon atoms) or a bicycle having 7 to 10 ring members (4 to 9 carbon atoms and 1 to 3 heteroatoms selected from N, O, P, and S) (e.g., bicyclic [4,5], [5,5], [5,6], or [6,6] systems).

[0219] As used herein, "heteroaryl" and "heterocycloalkyl" refer to an aromatic or non-aromatic ring system, respectively, in which one or more ring atoms is a heteroatom, such as nitrogen, oxygen, and sulfur. A heteroaryl or heterocycloalkyl radical can be a heterocyclic ring system consisting of two or more heteroatoms. Heteroaryl or heterocycloalkyl may be monocyclic having 3 to 7 ring members (2 to 6 carbon atoms and 1 to 3 heteroatoms selected from N, O, P, and S), or may be bicyclic having 7 to 10 ring members (4 to 9 carbon atoms and 1 to 3 heteroatoms selected from N, O, P, and S) (e.g., bicyclic [4,5], [5,5], [5,6], or [6,6] systems). Heteroaryl and heterocycloalkyl may be unsubstituted or substituted. It may have been replaced.

[0220] Heteroaryl and heterocycloalkyl groups are described in Paquette, Leo A.; "Principles of Modern Heterocyclic Chemistry" (W. A. Benjamin, New York, 1968), particularly Chapters 1, 3, 4, 6, 7, and 9; "The Chemistry of Heterocyclic Compounds, A series of Monographs" (John Wiley & Sons, New York, 1950 to present), particularly Volumes 13, 14, 16, 19, and 28; and J. Am. Chem. Soc. (1960) 82:5566.

[0221] Examples of heteroaryl groups include, for example, but not limited to, pyridyl, thiazolyl, tetrahydrothiophenyl, pyrimidinyl, furanyl, thienyl, pyrrolyl, pyrazolyl, imidazolyl, tetrazolyl, benzofuranyl, thianaphthalenyl, indolyl, indolenyl, quinolinyl, isoquinolinyl, benzimidazolyl, isoxazolyl, pyrazinyl, pyridazinyl, indolizinyl, isoindolyl, 3H-indolyl, 1H-indazolyl, purinyl, 4H-quinolizinyl, phthalazinyl, naphthyridinyl, quinoxalinyl, quinazolinyl, cinnolinyl, pteridinyl, 4aH-carbazolyl, carbazolyl, phenanthridinyl, acridinyl, pyrimidinyl, phenanthrolinyl, phenazinyl, phenothiazinyl, phthalazinyl, phenoxazinyl, isochromanyl, chromanyl, imidazolidinyl, imidazolinyl, pyrazolidinyl, pyrazolinyl, benzotriazolyl, benzisoxazolyl, and isatinoyl.

[0222] ​Examples of heterocycloalkyls include, for example, but not limited to, dihydropyridyl, tetrahydropyridyl (piperidyl), tetrahydrothiophenyl, piperidinyl, 4 - piperidonyl, pyrrolidinyl, 2 - pyrrolidonyl, tetrahydrofuranyl, tetrahydropyranyl, bis - tetrahydrofuranyl, tetrahydroquinolinyl, tetrahydroiso quinolinyl, decahydroquinolinyl, octahydroisoquinolinyl, piperazinyl, quinuclidinyl, and morpholinyl.

[0223] By way of non - limiting example, carbon - bonded heteroaryls and heterocycloalkyls are bonded at the 2, 3, 4, 5, or 6 positions of pyridine, the 3, 4, 5, or 6 positions of pyridazine, the 2, 4, 5, or 6 positions of pyrimidine, the 2, 3, 5, or 6 positions of pyrazine, the 2, 3, 4, or 5 positions of furan, tetrahydrofuran, thiophene, pyrrole or tetrahydropyrrole, the 2, 4, or 5 positions of oxazole, imidazole or thiazole, the 3, 4, or 5 positions of isoxazole, pyrazole, or isothiazole, the 2 or 3 positions of aziridine, the 2, 3 or 4 positions of azetidine, the 2, 3, 4, 5, 6, 7, or 8 positions of quinoline, or the 1, 3, 4, 5, 6, 7, or 8 positions of isoquinoline. More typically carbon - bonded heterocycles include 2 - pyridyl, 3 - pyridyl, 4 - pyridyl, 5 - pyridyl, 6 - pyridyl, 3 - pyridazinyl, 4 - pyridazinyl, 5 - pyridazinyl, 6 - pyridazinyl, 2 - pyrimidinyl, 4 - pyrimidinyl, 5 - pyrimidinyl, 6 - pyrimidinyl, 2 - pyrazinyl, 3 - pyrazinyl, 5 - pyrazinyl, 6 - pyrazinyl, 2 - thiazolyl, 4 - thiazolyl, or 5 - thiazolyl.

[0224] ​By way of example and not limitation, nitrogen-bonded heteroaryls and heterocycloalkyls include aziridine, azetidine, pyrrole, pyrrolidine, 2-pyrroline, 3-pyrroline, imidazole, imidazolidine, 2-imidazoline, 3-imidazoline, pyrazole, pyrazoline, 2-pyrazoline, 3-pyrazoline, piperidine, piperazine, indole, indoline, the 1-position of 1H-indazole, the 2-position of isoindole or isoindoline, the 4-position of morpholine, and the 9-position of carbazole or beta-carboline. More typically, nitrogen-bonded heterocycles include 1-aziridyl, 1-azetedyl, 1-pyrrolyl, 1-imidazolyl, 1-pyrazolyl, and 1-piperidinyl. They are bonded at the 1-position of indazole, the 2-position of isoindole or isoindoline, the 4-position of morpholine, and the 9-position of carbazole or beta-carboline. Further typically, as nitrogen-bonded heterocycles, there are 1-aziridyl, 1-azetedyl, 1-pyrrolyl, 1-imidazolyl, 1-pyrazolyl, and 1-piperidinyl. As used in this application, and as applicable to any of the above alkyl, alkenyl, alkynyl, aryl, arylalkyl, cycloalkyl, heteroaryl, heterocyclyl, etc., "substituted" means that one or more hydrogen atoms are each independently replaced by a substituent.

[0225] Typical substituents include, but are not limited to, -X, -R, -OH, -OR, -SH, -SR, NH2, -NHR, -N(R)2, -N(R)3, -CX3, -CN, -OCN, -SCN, -NCO, -NCS, -NO, -NO2, -N3, -NC(=O)H, -NC(=O)R, -C(=O)H, -C(=O)R, -C(=O)NH2, -C(=O)N(R)2, + -SO3-, -SO3H, -S(=O)2R, -OS(=O)2OR, -S(=O)2NH -S(=O)2N(R)2, -S(=O)R, -OP(=O)(OH) -OP(=O)(OR)2, -P(=O)(OR)2, -PO3, -PO3H2, -C(=O)X, -C(=S)R, -CO2H, -CO2R, -CO2-, -C(=S)OR, -C(=O)SR, -C(=S)SR, -C(=O)NH 2, -S(=O)2N(R)2, -S(=O)R, -OP(=O)(OH) 2, -OP(=O)(OR)2, -P(=O)(OR)2, -PO3, -PO3H2, -C(=O)X, -C(=S)R, -CO2H, -CO2R, -CO2-, -C(=S)OR, -C(=O)SR, -C(=S)SR, -C(=O)NH2, -C(=O)N(R)2, -C(=S)NH 2, -C(=S)N(R)2, -C(=NH)NH 2, and -C(=NR)N(R)2; wherein each X is independently selected in each case from F, Cl, Br, and I; and each R is C1-C 12 alkyl, C6-C 20 aryl, C3-C 14 heterocycloalkyl or heteroaryl, protecting groups and prodrugs is independently selected in each case from moieties. Whenever a group is described as "optionally substituted", that group may be independently substituted in each case with one or more of the above substituents.

[0226] It should be understood that certain radical naming conventions may, depending on the circumstances, include either mono-radicals or di-radicals. For example, when a substituent requires the positions of two bonds to the remainder of the molecule, the substituent is understood to be a di-radical. For example, substituents identified as alkyl that require the positions of two bonds include di-radicals such as -CH2-, -C H2CH2-, -CH2CH(CH3)CH2-, etc. Other radical naming conventions clearly indicate that the radical is a di-radical such as "alkylene", "alkenylene", "arylene", "heterocycloalkylene", etc. Whenever a substituent is shown as a di-radical (i.e., having the positions of two bonds to the remainder of the molecule), it should be understood that the substituent may be attached in any directional arrangement, unless otherwise specified.

[0227] Whenever a substituent is shown as a di-radical (i.e., having the positions of two bonds to the remainder of the molecule) ), it should be understood that the substituent may be attached in any directional arrangement, unless otherwise specified.

[0228] ​"Isomerism" means compounds that have the same molecular formula but differ in the sequence of bonding of their atoms or the spatial arrangement of their atoms. Isomers with different spatial arrangements of their atoms are called "stereoisomers". Stereoisomers that are not mirror images of each other are called "diastereomers", and stereoisomers that are mirror images and cannot be superimposed on each other are called "enantiomers", sometimes also called "optical isomers".

[0229] A carbon atom bonded to four non-identical substituents is called a "chiral center". "Chiral isomers" mean compounds having at least one chiral center. Compounds having one or more chiral centers may exist as individual diastereomers or as a mixture of diastereomers called a "diastereomeric mixture". When there is one chiral center, the stereoisomers can be characterized by the absolute configuration (R or S) of that chiral center. Absolute configuration refers to the spatial arrangement of the substituents bonded to the chiral center. The substituents bonded to the chiral center under consideration are ranked according to the sequence rules of Cahn, Ingold, and Prelog. (Cahn et al., Angew. Chem. Inter. Edit. 1966, 5, 385; errata 511; Cahn et al., Angew. Chem. 1966, 78, 413; Cahn and Ingold, J. Chem. Soc. 1951 (London), 612; Cahn et al., Experientia 1956, 12, 81; Cahn, J. Chem. Educ. 1964, 41, 116). A mixture containing equal amounts of the individual enantiomeric forms with opposite chirality is called a "racemic mixture".

[0230] The compounds disclosed in this specification and the claims may contain one or more asymmetric centers. Certain compounds may exist as different diastereomers and / or enantiomers. In this specification and the claims, the description of any compound, unless otherwise stated, is meant to include all enantiomers, diastereomers, and mixtures thereof. Further, in this specification and the claims, the description of any compound, unless otherwise stated, is meant to include the individual enantiomers, as well as any mixture, racemate, or other thereof of said enantiomers. When the structure of a compound is depicted as a specific enantiomer, it should be understood that the disclosure of this application is not limited to that specific enantiomer. Accordingly, the enantiomers, optical isomers, and diastereomers of each structural formula of the present disclosure are contemplated in this application. In this specification, the structural formula of said compound is, for convenience, in some cases, representative of a specific isomer, but it is understood that the present disclosure includes all isomers such as geometric isomers, optical isomers based on asymmetric carbons, stereoisomers, tautomers, etc., and that not all isomers have the same level of activity. These compounds may exist in different tautomeric forms. The compounds according to the present disclosure, unless otherwise stated, are meant to include all tautomeric forms. When the structure of a compound is depicted as a specific tautomer, it should be understood that the disclosure of this application is not limited to that specific tautomer.

[0231] Any compound of any formula described in this application, where applicable, includes the compound itself, as well as its salts, and solvates thereof. For example, the salt may be formed between an anion and a positively charged group (e.g., amino) on the compound of the present disclosure. Suitable anions include chloride, bromide, iodide, sulfate, bisulfate, sulfamate, nitrate, phosphate, citrate, methanesulfonate, trifluoroacetate , glutamate, glucuronate, glutarate, malate, maleate, succinate, fumarate, tartrate, tosylate, salicylate, lactate, naphthalenesulfonate, and acetate (e.g., trifluoroacetate). The term "pharmaceutically acceptable anion" refers to a suitable anion for forming a pharmaceutically acceptable salt. Similarly, the salt may be formed between a cation and a negatively charged group (e.g., carboxylate) on the compounds of the present disclosure. Suitable cations include sodium ions, potassium ions, magnesium ions, calcium ions, and ammonium cations such as tetramethylammonium ions. Examples of some suitable substituted ammonium ions include those derived from: ethylamine, diethylamine, dicyclohexylamine, triethylamine, butylamine, ethylenediamine, ethanolamine, diethanolamine, piperazine, benzylamine, phenylbenzylamine, choline, meglumine, and tromethamine, amino acids such as lysine and arginine. The compounds of the present disclosure also include salts containing a quaternary nitrogen atom. Examples of suitable inorganic anions include, but are not limited to, those derived from the following inorganic acids: hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, sulfurous acid, nitric acid, nitrous acid, phosphoric and phosphorous. Examples of suitable organic anions include, but are not limited to, the following Those derived from the following organic acids may be mentioned: 2-acetoxybenzoic acid, acetic acid, ascorbic acid, aspartic acid, benzoic acid, camphorsulfonic acid, cinnamic acid, citric acid, edetic acid, ethanedisulfonic acid, ethanesulfonic acid, fumaric acid, gluceptonic acid, gluconic acid, glutamic acid, glycolic acid, hydroxymaleic acid, hydroxynaphthalene-carboxylic acid, isethionic acid, lactic acid, lactobionic acid, lauric acid, maleic acid, malic acid, methanesulfonic acid, mucic acid, oleic acid, oxalic acid, palmitic acid, pamoic acid, pantothenic acid, phenylacetic acid, phenylsulfonic acid, propionic acid, pyruvic acid, salicylic acid, stearic acid, succinic acid, sulfanilic acid, tartaric acid, toluenesulfonic acid, and valeric acid. Examples of suitable polymeric organic anions include, but are not limited to, those derived from the following polymeric acids: tannic acid, carboxymethyl-cellulose.

[0232] Furthermore, the compounds of the present disclosure (e.g., salts of the said compounds) may exist in the form of hydrates or non-hydrates (anhydrous) forms, or as solvates with other solvent molecules. Non-limiting examples of hydrates include monohydrates, dihydrates, etc. Non-limiting examples of solvates include ethanol solvates, acetone solvates, etc. "Solvate" means a form in which a solvent has been added, containing either a stoichiometric or non-stoichiometric amount of the solvent. Some compounds have a tendency to trap solvent molecules in a fixed molar ratio in the crystalline solid phase, thereby forming solvates. And when the said solvent is water, the solvate formed is a hydrate; and when the said solvent is an alcohol, the solvate formed is an alcoholate. Hydrates are formed by the combination of one molecule of a substance and one or more molecules of water, in which the water retains its molecular state as H2O. Hydrates refer to, for example , monohydrates, dihydrates, trihydrates, etc.

[0233] Furthermore, for the compounds or salts thereof represented by the formulas disclosed in the present application, there may exist crystal polymorphs. It should be noted that any crystalline form, a mixture of crystalline forms, or their anhydrides or hydrates are included within the scope of the present disclosure.

[0234] Anti-CD45 antibody which is capable of binding to CD45 and can be used alone as a therapeutic agent or as an antibody-drug conjugate (ADC) to, for example, (i) treat cancer and autoimmune diseases characterized by CD45+ cells, (ii) promote engraftment of transplanted hematopoietic stem cells in patients in need of transplantation therapy is contemplated in the present application. These therapeutic activities may be caused, for example, by binding of an isolated anti-CD45 antibody, its antigen-binding fragment, or ADCs to CD45 expressed on the surface of cells (such as cancer cells, autoimmune cells, or hematopoietic stem cells, etc.), and then induction of cell death. Reduction of endogenous hematopoietic stem cells may provide a niche to which transplanted hematopoietic stem cells can home, and subsequently, productive hematopoiesis may be established. In this way, transplanted hematopoietic stem cells can successfully engraft in a patient (such as a human patient suffering from a stem cell disorder described in the present application). Furthermore, in a patient, when leukocytes are reduced in combination with HSC transplantation ( which the patient requires), the patient's immune system can be reset, thereby, for example, curing a patient with an autoimmune disease. fragment, or ADCs, and then cell death is induced. Reduction of endogenous hematopoietic stem cells may provide a niche to which transplanted hematopoietic stem cells can home, and subsequently, productive hematopoiesis may be established. In this way, transplanted hematopoietic stem cells can successfully engraft in a patient (such as a human patient suffering from a stem cell disorder described in the present application). Furthermore, in a patient, when leukocytes are reduced in combination with HSC transplantation ( which the patient requires), the patient's immune system can be reset, thereby, for example, curing a patient with an autoimmune disease.

[0235] CD45 (also known as leukocyte common antigen and receptor-type tyrosine-protein phosphatase C) is a hematopoietic cell-specific transmembrane protein tyrosine phosphatase that is essential for signal transduction via the T and B cell antigen receptors. CD45 contains a large extracellular domain and a phosphatase containing a cytoplasmic domain. CD45 can act as both a positive and negative regulator depending on the nature of the stimulus and the cell type involved. The CD45 gene has various rearrangements, but only six isoforms have been identified in humans to date. The isoforms are RA, RO, RB, RAB, RBC and RABC (Hermiston et al. 2003 “CD45: a critical regulator of signaling thresholds in immune cells.” Annu Rev Immunol. 2:107-137.). CD45RA is expressed on naive T cells, and CD45RO is expressed on activated and memory T cells, some B cell subsets, activated monocytes / macrophages, and granulocytes. CD45RB is expressed on peripheral B cells, naive T cells, thymocytes, weakly on macrophages, and dendritic cells. The amino acid sequence of CD45RABC is provided in this application as SEQ ID NO: 112. The amino acid sequence of CD45RA is provided in this application as SEQ ID NO: 107. The amino acid sequence of CD45RO is provided in this application as SEQ ID NO: 108. The amino acid sequence of CD45RB is provided in this application as SEQ ID NO: 109. The amino acid sequence of CD45RAB is provided in this application as SEQ ID NO: 110. The amino acid sequence of SEQ ID NO: RBC is provided in this application as SEQ ID NO: 111.

[0236] As described below, in certain embodiments, novel anti-human CD45 (hCD45) antibodies were identified by screening a yeast display library displaying fully human antibodies. In said screening, seven human antibodies (antibody 1 (Ab1), antibody 2 (Ab2), antibody 3 (Ab3), antibody 4 (Ab4), antibody 5 (Ab5), antibody 6 (Ab6), and antibody 7 (Ab7)) were identified . These bind to human CD45 (all isoforms) and cross-react with CD45 from non-human primates ( e.g., cynomolgus CD45 and / or rhesus CD45).

[0237] In other embodiments, humanized and affinity matured antibodies were prepared from three rat anti-CD45 antibodies. In this way, three further antibodies (antibody A (AbA), antibody B (AbB), and antibody C (AbC) so named) were identified. These bind to human CD45 (all isoforms) and cross-react with CD45 from non- human primates (e.g., cynomolgus CD45 and / or rhesus CD45). The identified antibodies have diagnostic and therapeutic properties as described in the present application.[[ID=I3]]

[0238] Accordingly, the present application provides an antibody, or an antigen-binding portion thereof, that specifically binds to human CD45 and cross- reacts with CD45 from non-human primates.

[0239] In one embodiment, the invention provides an antibody, or an antigen-binding portion thereof, that binds to human CD45 (SEQ ID NO: 112) and cynomolgus CD45 (SEQ ID NO: 145) and / or rhesus CD45 (SEQ ID NO: 146). In some embodiments, said antibody, its antigen-binding portion, is by Biolayer Interferometry (BLI) Thus, when measured, the K is about 100 nM or less, for example, about 100 nM or less, about 90 nM or less, about 80 nM or less, about 70 nM or less, about 60 nM or less, about 50 nM or less, about 40 nM or less, about 30 nM or less, about 20 nM or less, about 10 nM or less, about 10 nM or less, or about 0.1 nM or less, and may bind to human CD45. In some embodiments, the antibody, its antigen-binding portion, when measured by Bio-Layer Interferometry (BLI), has a K of about 100 nM or less, for example, about 100 nM or less, about 90 nM or less, about 80 nM or less, about 70 nM or less, about 60 nM or less, about 50 nM or less, about 40 nM or less, about 30 nM or less, about 20 nM or less, about 10 nM or less, about 10 nM or less, or about 0.1 nM or less, and may bind to cynomolgus CD45. In some embodiments, the antibody, its antigen-binding portion, when measured by Bio-Layer Interferometry (BLI), has a K of about 100 nM or less, for example, about 100 nM or less, about 90 nM or less, about 80 nM or less, about 70 nM or less, about 60 nM or less, about 50 nM or less, about 40 nM or less, about 30 nM or less, about 20 nM or less, about 10 nM or less, about 10 nM or less, or about 0.1 nM or less, and may bind to rhesus CD45. In some embodiments, the antibody is a fully human antibody or its antigen-binding portion. In other embodiments, the antibody is a humanized antibody or its antigen-binding portion. In some embodiments, the antibody is a chimeric antibody or its antigen-binding portion. In some embodiments, the antibody is a deimmunized antibody or its antigen-binding portion. D and may bind to human CD45. In some embodiments, the antibody, its antigen-binding portion, when measured by Bio-Layer Interferometry (BLI), has a K of about 100 nM or less, for example, about 100 nM or less, about 90 nM or less, about 80 nM or less, about 70 nM or less, about 60 nM or less, about 50 nM or less, about 40 nM or less, about 30 nM or less, about 20 nM or less, about 10 nM or less, about 10 nM or less, or about 0.1 nM or less, and may bind to cynomolgus CD45. D In some embodiments, the antibody, its antigen-binding portion, when measured by Bio-Layer Interferometry (BLI), has a K of about 100 nM or less, for example, about 100 nM or less, about 90 nM or less, about 80 nM or less, about 70 nM or less, about 60 nM or less, about 50 nM or less, about 40 nM or less, about 30 nM or less, about 20 nM or less, about 10 nM or less, about 10 nM or less, or about 0.1 nM or less, and may bind to rhesus CD45. D and may bind to rhesus CD45. In some embodiments, the antibody is a fully human antibody or its antigen-binding portion. In other embodiments, the antibody is a humanized antibody or its antigen-binding portion. In some embodiments, the antibody is a chimeric antibody or its antigen-binding portion. In some embodiments, the antibody is a deimmunized antibody or its antigen-binding portion.

[0240] The extracellular region of human CD45 contains a mucin-like domain and four fibronectin-like domains (d1, d2, d3, and d4). Without wishing to be bound by any theory, antibodies Ab1, Ab2, Ab3, Ab4, Ab5, Ab6, and Ab7 are thought to interact with residues of human CD45 located within the fibronectin-like domains of d3 and d4. In particular, these antibodies may interact with the fragment of human CD45 set forth in SEQ ID NO: 115, and the fragment of human CD45 set forth in SEQ ID NO: 117. According to the cross-linking assays described in this application, the antibodies are specifically capable of interacting with one or more CD45 amino acid residues that are conserved among human CD45, cynomolgus monkey CD45, and rhesus monkey CD45. These residues include 405T, 407K, 419Y, 425K, and 505R (numbered with reference to the fragment of hCD45 set forth in SEQ ID NO: 113). Additionally, these antibodies may interact with residue 481R and / or 509H in human CD45 (numbered with reference to the fragment of hCD45 set forth in SEQ ID NO: 113). Thus, in some embodiments, this application provides antibodies that bind to human CD45, or antigen-binding portions thereof, at epitopes located within the fibronectin-like domains of d3 and / or d4. In some embodiments, this application provides antibodies that bind to human CD45, or antigen-binding portions thereof, at epitopes of human CD45 located within CD45 fragment 2 (SEQ ID NO: 115) and / or CD45 fragment 4 (SEQ ID NO: 117). In some embodiments, this application provides epitopes of human CD45 located within CD45 fragment 1 (SEQ ID NO: 114) and / or CD45 fragment 3 (SEQ ID NO: 116) It is suggested that it can be done. These residues include 405T, 407K, 419Y, 425K, and 505R (numbered with reference to the fragment of hCD45 set forth in SEQ ID NO: 113). are included. Furthermore, these antibodies may interact with residue 481R and / or 509H in human CD45 (numbered with reference to the fragment of hCD45 set forth in SEQ ID NO: 113). Accordingly, in some embodiments, this application provides antibodies that bind to human CD45, or antigen-binding portions thereof, at epitopes located within CD45 fragment 2 (SEQ ID NO: 115) and / or CD45 fragment 4 (SEQ ID NO: 117) of human CD45. In some embodiments, this application provides antibodies that bind to human CD45, or antigen-binding portions thereof, at epitopes of human CD45 located within CD45 fragment 1 (SEQ ID NO: 114) and / or CD45 fragment 3 (SEQ ID NO: 116). Provided is an antibody that binds to CD45, or an antigen-binding portion thereof. In some embodiments, the present application provides at least 1, at least 2, at least 3, at least 4, or at least 5 amino acid residues conserved among human CD45, cynomolgus CD45, and / or rhesus CD45, and provides an antibody that binds to CD45, or an antigen-binding portion thereof, with an epitope containing the amino acid residues. For example, in some embodiments, the antibody, or an antigen-binding portion thereof, may bind to at least 1, at least 2, at least 3, at least 4, or all 5 of the following amino acid residues in human CD45: 405T, 407K, 419Y, 425K, and 505R ( numbered with reference to the fragment of hCD45 set forth in SEQ ID NO: 113). In some embodiments, the antibody, or an antigen-binding portion thereof, may bind to 1 or more, 2 or more, 3 or more, 4 or more, 5 or more, 6 or more, or 7 of the following amino acid residues in human CD45: 405T, 407K, 419Y, 425K, 481R and 505R, 509H (numbered with reference to the fragment of hCD45 set forth in SEQ ID NO: 113). The present application also provides an antibody, or an antigen-binding portion thereof, that competes with Ab1, Ab2, Ab3, Ab4, Ab5, Ab6, and / or Ab7 for binding to human CD45 (SEQ ID NO: 112). In some embodiments, the antibody, or an antigen-binding portion thereof, may also compete with Ab1, Ab2, Ab3, Ab4, Ab5, Ab6, and / or Ab7 for binding to cynomolgus CD45 (SEQ ID NO: 145) and / or rhesus CD45 (SEQ ID NO: 146). In some embodiments, the antibody is a fully human antibody, or an antigen-binding portion thereof. In other embodiments, The antibody is a humanized antibody or an antigen-binding portion thereof. In some embodiments, the antibody is a chimeric antibody or an antigen-binding portion thereof. In some embodiments, the antibody is a deimmunized antibody or an antigen-binding portion thereof.

[0241] While not wishing to be bound by any theory, the antibody AbA described in the present application also binds to the d4 fibronectin-like domain of CD45, but is thought not to compete with any of Ab1-Ab7 for binding to CD45. According to the epitope mapping experiments described in the present application, AbA binds to the d4 fibronectin-like domain on the opposite face of the CD45 molecule compared to Ab1-Ab7. In particular, this antibody is thought to interact with the fragment of human CD45 described in SEQ ID NO: 118. According to the cross-linking assays described in the present application, AbA can specifically interact with one or more CD45 amino acid residues that are conserved among human CD45, cynomolgus monkey CD45, and rhesus monkey CD45 as shown. These residues include 493Y and 502T (numbered with reference to the fragment of hCD45 described in SEQ ID NO: 113). Furthermore, this antibody may interact with residue 486R in human CD45 (numbered with reference to the fragment of hCD45 described in SEQ ID NO: 113). Thus, in some embodiments, the present application relates to an epitope located within the d4 fibronectin-like domain that binds to human CD45 In some embodiments, the present application provides antibodies, or antigen-binding portions thereof, that bind to CD45 at an epitope of human CD45 located within CD45 fragment 5 (SEQ ID NO: 118). ... an antibody that binds to CD45 with an epitope comprising one or at least two amino acid residues, or For example, in some embodiments, the antibody, or antigen-binding portion thereof, may bind to one or both of the following amino acid residues in human CD45: 493Y and 502T (with reference to the fragment of hCD45 set forth in SEQ ID NO: 113) In some embodiments, the antibody, or antigen-binding portion thereof, may bind to one or more, two or more, or three of the following amino acid residues in human CD45: 486R, 493Y, and 502T (referring to the fragment of hCD45 set forth in SEQ ID NO:113). The present application also provides an antibody, or antigen-binding portion thereof, that competes with AbA for binding to human CD45 (SEQ ID NO: 112). In some embodiments, The antibody, or antigen-binding portion thereof, also competes with AbA for binding to cynomolgus monkey CD45 (SEQ ID NO: 145) and / or rhesus monkey CD45 (SEQ ID NO: 146). In some embodiments, the antibody is a fully human antibody, or an antigen-binding portion thereof. In other embodiments, the antibody is a humanized antibody, or an antigen-binding portion thereof. In some embodiments, the antibody is a chimeric antibody, or an antigen-binding portion thereof. In some embodiments, the antibody is a deimmunized antibody, or an antigen-binding portion thereof.

[0242] In other embodiments, the present application provides an antibody, or an antigen-binding portion thereof, that binds to the same epitope of human CD45 as AbB. In some embodiments, the antibody, or the antigen-binding portion thereof, cross-reacts with cynomolgus CD45 and / or rhesus CD45. The present application also provides an antibody, or an antigen-binding portion thereof, that competes with AbB for binding to human CD45 (SEQ ID NO: 112). In some embodiments, the antibody, or the antigen-binding portion thereof, may also compete with AbB for binding to cynomolgus CD45 (SEQ ID NO: 145) and / or rhesus CD45 (SEQ ID NO: 146). In some embodiments the antibody is a fully human antibody, or an antigen-binding portion thereof. In other embodiments, the antibody is a humanized antibody, or an antigen-binding portion thereof. In some embodiments, the antibody is a chimeric antibody, or an antigen-binding portion thereof. In some embodiments, the antibody is a deimmunized antibody, or an antigen-binding portion thereof.

[0243] In other embodiments, the present application provides an antibody, or an antigen-binding portion thereof, that binds to the same epitope of human CD45 as AbC. In some embodiments, the antibody, or the antigen-binding portion thereof, cross-reacts with cynomolgus CD45 and / or rhesus CD45. The present application also provides an antibody, or an antigen-binding portion thereof, that competes with AbC for binding to human CD45 (SEQ ID NO: 112). In some embodiments, the antibody, or the antigen-binding portion thereof, may also compete with AbC for binding to cynomolgus CD45 (SEQ ID NO: 145) and / or rhesus CD45 (SEQ ID NO: 146). In some embodiments The antibody is a fully human antibody or an antigen-binding portion thereof. In other embodiments, the antibody is a humanized antibody or an antigen-binding portion thereof. In some embodiments, the antibody is a chimeric antibody or an antigen-binding portion thereof. In some embodiments, the antibody is a deimmunized antibody or an antigen-binding portion thereof.

[0244] The various binding regions of anti-CD45 antibodies Ab1, Ab2, Ab3, Ab4, Ab5, Ab6, Ab7, AbA, AbB, and AbC The amino acid sequences are set forth in Table 27. In various aspects, the present invention provides an antibody comprising a heavy chain and / or light chain CDR sequence of an antibody set forth in Table 27. In some aspects, the present invention provides an antibody comprising a heavy chain variable region and / or a light chain variable region of an antibody set forth in Table 27. In some aspects, the present invention provides an antibody comprising a heavy chain and / or a light chain of an antibody set forth in Table 27. Additional features of the antibodies and antigen-binding portions thereof provided by this application are described below.

[0245] Ab1 Antibody 1 (Ab1) can cross-react with human CD45, cynomolgus monkey CD45, and rhesus monkey CD45 and can bind to various isoforms of human CD45.

[0246] The amino acid sequences of the various binding regions of anti-CD45 Ab1 are set forth in Table 27. For example, anti-CD45 antibodies based on Ab1 that contain the CDRs set forth in Table 27 are included in the present invention. are included in the present invention.

[0247] In one embodiment, the present invention provides an anti-CD45 antibody, or an antigen-binding fragment thereof, comprising an antigen-binding region corresponding to the antigen-binding region of Ab1, such as a CDR and / or variable region. The amino acid sequence of the heavy chain variable region (VH) of Ab1 is set forth in SEQ ID NO: 1 (see Table 27) The amino acid sequences of the VH CDR domains of Ab1 are set forth in SEQ ID NO: 2 (VH CDR1), SEQ ID NO: 3 (VH CDR2), and SEQ ID NO: 4 (VH CDR3). The chain variable region (VL) amino acid sequence is set forth in SEQ ID NO: 5 (see Table 27). The VL CDR domain amino acid sequences of Ab1 are set forth in SEQ ID NO: 6 (VL CDR1), SEQ ID NO: 7 (VL CDR2), and SEQ ID NO: 8 (VL CDR3).

[0248] Thus, in some embodiments, the present application provides the amino acid sequence set forth in SEQ ID NO:2. a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 3; a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 3; a main fragment containing a CDR3 domain having the amino acid sequence set forth in SEQ ID NO: 4; and / or a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:6. In certain embodiments, the present invention provides an anti-CD45 antibody, or antigen-binding portion thereof, comprising: a light chain variable region comprising: a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 7; and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 8. In certain embodiments, the anti-CD45 antibody comprises the CDRs described in this application (SEQ ID Nos: 2-4 and 6-8), wherein the CDRs comprise a conservative 1 amino acid substitution (or 2, 3, 4, or 5 amino acid substitutions) while retaining the CD45 specificity of the antibody (i.e., specificity similar to Ab1).

[0249] In some embodiments, the present application provides a method for the preparation of a nucleic acid sequence comprising the amino acid sequence set forth in SEQ ID NO:1. and / or a light chain comprising the amino acid sequence set forth in SEQ ID NO:5. Provided is an anti-CD45 antibody, or an antigen-binding portion thereof, that includes a variable region. In certain embodiments the antibody may include a modified heavy chain (HC) variable region that includes an HC variable domain that includes SEQ ID NO:1, or a variant of SEQ ID NO:1, where the variant differs from SEQ ID NO:1 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids; and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85% , 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:1, where in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and where the modified heavy chain variable region retains the CD45 specificity of the antibody (i.e., specificity similar to Ab1) or has enhanced biological activity as compared to the biological activity of another Ab1 heavy chain variable region. In certain embodiments, the antibody includes a modified light chain (LC) variable region that includes an LC variable domain that includes SEQ ID NO:5, or a variant of SEQ ID NO:5, where the variant differs from SEQ ID NO:5 in (i) a substitution, addition or deletion of 1, 2 , 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids ; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids ; and (iv) an amino acid sequence that is at least about 75%, 80%, 85% in substitution, addition or deletion, an amino acid sequence that is different from SEQ ID NO:5 and / or (iv) is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:5, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein the modified light chain variable region retains the CD45 specificity of the antibody (i.e., the specificity similar to Ab1), or has enhanced biological activity compared to the biological activity of another Ab1 light chain variable region has.

[0250] Antibodies comprising the CDR and / or variable region sequences of Ab1 may be in the form of full-length antibodies, bispecific antibodies, dual variable domain antibodies, multi-chain or single-chain antibodies, and / or binding fragments that specifically bind to human CD45, for example, but not limited to, Fab, Fab', (Fab')2, Fv, scFv (single-chain Fv), camelid antibody (including constructs of surrogate light chains), single domain antibodies, llama antibodies, etc. They may also be of any isotype (e.g., IgA (e.g., IgA1 or IgA2), IgD, IgE, IgG (e.g., IgG1, IgG2, IgG3 or IgG4), or IgM, etc.), or may be derived therefrom. In some embodiments, the anti-CD45 antibody is IgG (e.g., IgG1, IgG2, IgG3 or IgG4). constructs), single domain antibodies, llama antibodies, etc. They may also be of any isotype (e.g., IgA (e.g., IgA1 or IgA2), IgD, IgE, IgG (e.g., IgG1, IgG2, IgG3 or IgG4), or IgM, etc.), or may be derived therefrom. In some embodiments, the anti-CD45 antibody is IgG (e.g., IgG1, IgG2, IgG3 or IgG4). IgG1, IgG2, IgG3 or IgG4), or IgM, etc.), or may be derived therefrom. In some embodiments, the anti-CD45 antibody is IgG (e.g., IgG1, IgG2, IgG3 or IgG4).

[0251] ​​In some embodiments, an antibody comprising the CDR and / or variable region sequence of Ab1 may further comprise a heavy chain constant region and / or a light chain constant region. In some embodiments, the constant region is a human IgG1 constant region, a human IgG2 constant region, a human IgG3 constant region, or a human IgG4 constant region. In some embodiments, the heavy chain constant region may be a modified constant region. Exemplary constant region substitutions and / or modifications include substitutions at one or more of the following positions: 234, 235 , 265, and 435 (EU index according to Kabat). In some embodiments, an antibody comprising the CDR and / or variable region sequence of Ab1 may further comprise an IgG1 heavy chain constant region comprising one or more of the following substitutions: L234A, L235A, D265C, and H435A (EU index according to Kabat). In some embodiments, an antibody comprising the CDR and / or variable region sequence of Ab1 may further comprise a heavy chain constant region as set forth in SEQ ID NO: 102, SEQ ID NO: 103, SEQ ID NO: 104, SEQ ID NO: 105 or SEQ ID NO: 106. In some embodiments, the antibody comprises a light chain constant region as set forth in SEQ ID NO: 101 .

[0252] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 9. In certain embodiments, the antibody may comprise a modified heavy chain (HC) region comprising an HC domain comprising SEQ ID NO: 9, or a variant of SEQ ID NO: 9, wherein the variant is (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids, in SEQ (i) having a substitution, addition or deletion of at most 10, 9, 8, 7, 6, 5, 4, 3, 2 or 1 amino acid that is different from SEQ ID NO: 9; (ii) having a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acid that is different from SEQ ID NO: 9; (iii) having a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids that is different from SEQ ID NO: 9, and / or (iv) comprising an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 9, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and herein, the modified heavy chain region retains the CD45 specificity of the antibody (i.e., the specificity similar to Ab1) or has enhanced biological activity as compared to the biological activity of another Ab1 heavy chain region.

[0253] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 10. In certain embodiments, the antibody may comprise a modified light chain (LC) region comprising an LC domain comprising SEQ ID NO: 10, or a variant of SEQ ID NO: 10, wherein the variant (i) has a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids that is different from SEQ ID NO: 10; (ii) has a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acid that is different from SEQ ID NO: 10; (iii) has a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids that is different from SEQ ID NO: 10; and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 10, wherein in any of (i)-(iv), the amino acid substitution is either a conservative amino acid substitution or a non-conservative amino acid substitution good; and wherein said modified light chain region retains the CD45 specificity of said antibody (i.e., the specificity similar to Ab1), or has enhanced biological activity as compared to the biological activity of another Ab1 light chain region.

[0254] In some embodiments, an antibody comprising the CDR region and / or variable region of Ab1 may be incorporated into an antibody-drug conjugate as described in this application. Further, an antibody comprising the CDR region and / or variable region of Ab1 may be used, for example, for the reduction of CD45+ cells in a subject in the methods described in this application.

[0255] Ab2 Antibody 2 (Ab2) can cross-react with human CD45, cynomolgus monkey CD45 and rhesus monkey CD45, and can bind to various isoforms of human CD45.

[0256] The amino acid sequences of the various binding regions of anti-CD45 Ab2 are set forth in Table 27. For example, anti-CD45 antibodies based on Ab2 that contain the CDRs set forth in Table 27 are included in the present invention. are included in the present invention.

[0257] In one embodiment, the present invention provides an anti-CD45 antibody, or an antigen-binding fragment thereof, comprising an antigen-binding region corresponding to the antigen-binding region of Ab2, such as a CDR and / or variable region. The heavy chain variable region (VH) amino acid sequence of Ab2 is set forth in SEQ ID NO: 11 (see Table 27). The VH CDR domain amino acid sequence of Ab2 is set forth in SEQ ID NO: 12 (VH CDR1); SEQ The number (SEQ ID NO): 13 (VH CDR2) and the sequence number (SEQ ID NO): 14 (VH CDR3) are described in Ab2. The light chain variable region (VL) amino acid sequence of is described in the sequence number (SEQ ID NO): 15 (see Table 27). The VL CDR domain amino acid sequence of Ab2 is described in the sequence number (SEQ ID NO): 16 (VL CDR1); the sequence number (SEQ ID NO): 17 (VL CDR2) and the sequence number (SEQ ID NO): 18 (VL CDR3).

[0258] Accordingly, in some embodiments, the present application provides a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 12, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 13, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 14; and / or a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 16, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 17; and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 18. An anti-CD45 antibody, or an antigen-binding portion thereof, is provided. In certain embodiments, the anti-CD45 antibody comprises the CDRs (SEQ ID Nos: 12 to 14 and 16 to 18) described in the present application, wherein the CDRs contain conservative 1 amino acid substitutions (or 2, 3, 4, or 5 amino acid substitutions) while retaining the CD45 specificity of the antibody (i.e., a specificity similar to Ab2).

[0259] In some embodiments, the present application provides an anti-CD45 antibody, or an antigen-binding portion thereof, comprising a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 11, and / or a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 15. In certain embodiments In one form, the antibody may comprise a modified heavy chain (HC) variable region comprising an HC variable domain comprising SEQ ID NO: 11, or a variant of SEQ ID NO: 11, wherein said variant differs from SEQ ID NO: 11 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acid and differs from SEQ ID NO: 11; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids and differs from SEQ ID NO: 11, and / or (iv) comprises an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 11, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified heavy chain variable region retains the CD45 specificity of said antibody (i.e., a specificity similar to Ab2) or has enhanced biological activity compared to the biological activity of another Ab2 heavy chain variable region. In certain embodiments, the antibody comprises a modified light chain (LC) variable region comprising an LC variable domain comprising SEQ ID NO: 15, or a variant of SEQ ID NO: 15, wherein said variant differs from SEQ ID NO: 15 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acid and differs from SEQ ID NO: 15; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids and differs from SEQ ID NO: 15 and, and / or (iv) comprises an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 15, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified light chain variable region retains the CD45 specificity of said antibody (i.e., a specificity similar to Ab2) or has enhanced biological activity compared to the biological activity of another Ab2 light chain variable region. In certain embodiments, the antibody comprises a modified light chain (LC) variable region comprising an LC variable domain comprising SEQ ID NO: 15, or a variant of SEQ ID NO: 15, wherein said variant differs from SEQ ID NO: 15 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acid and differs from SEQ ID NO: 15; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids and differs from SEQ ID NO: 15, and / or (iv) comprises an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 15, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified light chain variable region retains the CD45 specificity of said antibody (i.e., a specificity similar to Ab2) or has enhanced biological activity compared to the biological activity of another Ab2 light chain variable region. In certain embodiments, the antibody comprises a modified light chain (LC) variable region comprising an LC variable domain comprising SEQ ID NO: 15, or a variant of SEQ ID NO: 15, wherein said variant differs from SEQ ID NO: 15 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acid wherein it differs from SEQ ID NO: 15; (iii) differs from SEQ ID NO: 15 in a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids, and / or (iv) comprises an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 15, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein the modified light chain variable region retains the CD45 specificity of the antibody (i.e., a specificity similar to Ab2) or has enhanced biological activity as compared to the biological activity of another Ab2 light chain variable region.

[0260] Antibodies comprising the CDR and / or variable region sequences of Ab2 may be in the form of a full-length antibody, a bispecific antibody, a dual variable domain antibody, a multi-chain or single-chain antibody, and / or a binding fragment that specifically binds to human CD45, for example, but not limited to, Fab, Fab', (Fab')2, Fv, scFv (single-chain Fv), a sarobody (including constructs of surrogate light chains ), a single domain antibody, a camelized antibody, etc. They may also be of any isotype (e.g., IgA (e.g., IgA1 or IgA2), IgD, IgE, IgG (e.g. , IgG1, IgG2, IgG3 or IgG4), or IgM, etc.), or may be derived therefrom. In some embodiments, the anti-CD45 antibody is IgG (e.g., IgG1, IgG2, IgG3 or IgG4).

[0261] In some embodiments, an antibody comprising the CDR and / or variable region sequences of Ab2 may further comprise a heavy chain constant region and / or a light chain constant region. In some embodiments, the constant region is a human IgG1 constant region, a human IgG2 constant region, a human IgG3 constant region, or a human IgG4 constant region. In some embodiments, the heavy chain constant region may be a modified constant region. Exemplary constant region substitutions and / or modifications include substitutions at one or more of the following positions: 234, 235 , 265, and 435 (EU index according to Kabat). In some embodiments, an antibody comprising the CDR and / or variable region sequences of Ab2 may further comprise an IgG1 heavy chain constant region comprising one or more of the following substitutions: L234A, L235A, D265C, and H435A (EU index according to Kabat). In some embodiments, an antibody comprising the CDR and / or variable region sequences of Ab2 may further comprise a heavy chain constant region as set forth in SEQ ID NO: 102, SEQ ID NO: 103, SEQ ID NO: 104, SEQ ID NO: 105 or SEQ ID NO: 106. In some embodiments, the antibody comprises a light chain constant region as set forth in SEQ ID NO: 101 .

[0262] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 19. In certain embodiments, the antibody may include a modified heavy chain (HC) region comprising an HC domain comprising SEQ ID NO: 19, or a variant of SEQ ID NO: 19, wherein said variant differs from SEQ ID NO: 19 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids; and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 19, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified heavy chain region retains the CD45 specificity of said antibody (i.e., specificity similar to Ab2) or has enhanced biological activity compared to the biological activity of another Ab2 heavy chain region. or a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids; and (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 19, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution. In certain embodiments, said anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 20. In certain embodiments, the antibody may include a modified light chain (LC) region comprising an LC domain comprising SEQ ID NO: 20, or a variant of SEQ ID NO: 20, wherein said variant differs from SEQ ID NO: 20 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids;

[0263] In certain embodiments, said anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 20. In certain embodiments, the antibody may include a modified light chain (LC) region comprising an LC domain comprising SEQ ID NO: 20, or a variant of SEQ ID NO: 20, wherein said variant differs from SEQ ID NO: 20 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; in a deletion, different from SEQ ID NO: 20; (iii) in a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids, different from SEQ ID NO: 20, and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 20, wherein in any of (i)-(iv), the amino acid substitution is either a conservative amino acid substitution or a non-conservative amino acid substitution, is acceptable; and wherein the modified light chain region retains the CD45 specificity of the antibody (i.e., a specificity similar to Ab2) or has enhanced biological activity compared to the biological activity of another Ab2 light chain region.

[0264] In some embodiments, an antibody comprising the CDR region and / or variable region of Ab2 may be incorporated into an antibody-drug conjugate as described in this application. Further, an antibody comprising the CDR region and / or variable region of Ab2 may be used, for example, in the methods described in this application for the reduction of CD45+ cells in a subject.

[0265] Ab3 Antibody 3 (Ab3) can cross-react with human CD45, cynomolgus monkey CD45 and rhesus monkey CD45 and can bind to various isoforms of human CD45.

[0266] The amino acid sequences of various binding regions of anti-CD45 Ab3 are set forth in Table 27. For example, anti-CD45 antibodies based on Ab3 that contain the CDRs set forth in Table 27 are included in the present invention.

[0267] In one embodiment, the present invention provides an anti-CD45 antibody, or an antigen-binding fragment thereof, comprising an antigen-binding region corresponding to the antigen-binding region of Ab3, such as a CDR and / or variable region. The amino acid sequence of the heavy chain variable region (VH) of Ab3 is set forth in SEQ ID NO:21 (see Table 27). The amino acid sequences of the VH CDR domain of Ab3 are set forth in SEQ ID NO:22 (VH CDR1); SEQ ID NO:23 (VH CDR2) and SEQ ID NO:24 (VH CDR3). The amino acid sequence of the light chain variable region (VL) of Ab3 is set forth in SEQ ID NO:25 (see Table 27). The amino acid sequences of the VL CDR domain of Ab3 are set forth in SEQ ID NO:26 (VL CDR1); SEQ ID NO:27 (VL CDR2) and SEQ ID NO:28 (VL CDR3). Accordingly, in some embodiments, the present application provides a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:22, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:23, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO:24; and / or a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO:26, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO:27; and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO:28,

[0268] comprising an anti-CD45 antibody, or an antigen-binding portion thereof. In certain embodiments, the anti-CD45 antibody comprises the CDRs described in the present application (SEQ ID Nos: 22 to 24 and 26 to 28), wherein the CDRs comprise conservative 1 amino acid substitutions (or 2, 3, 4, or 5 amino acid substitutions) while retaining the CD45 specificity of the antibody (i.e., a specificity similar to Ab3). In certain embodiments, the anti-CD45 antibody comprises the CDRs described in the present application (SEQ ID Nos: 22 to 24 and 26 to 28), wherein the CDRs comprise conservative 1 amino acid substitutions (or 2, 3, 4, or 5 amino acid substitutions) while retaining the CD45 specificity of the antibody (i.e., a specificity similar to Ab3).

[0269] In some embodiments, the present application provides an anti-CD45 antibody, or an antigen-binding portion thereof, comprising a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 21, and / or a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 25. In certain embodiments the antibody may comprise a modified heavy chain (HC) variable region comprising an HC variable domain comprising SEQ ID NO: 21, or a variant of SEQ ID NO: 21, wherein said variant differs from SEQ ID NO: 21 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids that differs from SEQ ID NO: 21; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids that differs from SEQ ID ID NO: 21, and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 21, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified heavy chain variable region retains the CD45 specificity of said antibody (i.e., a specificity similar to Ab3), or has enhanced biological activity as compared to the biological activity of another Ab3 heavy chain variable region. In certain embodiments, the antibody comprises a modified light chain (LC) variable region comprising an LC variable domain comprising SEQ ID NO: 25, or a variant of SEQ ID NO: 25, wherein said variant differs from SEQ ID NO: 25 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acid substitutions, additions or deletions that differ from SEQ ID NO: 25; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids that differs from SEQ ID NO: 25, and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 25, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified light chain variable region retains the CD45 specificity of said antibody (i.e., a specificity similar to Ab3), or has enhanced biological activity as compared to the biological activity of another Ab3 light chain variable region. In certain embodiments, the antibody comprises a modified light chain (LC) variable region comprising an LC variable domain comprising SEQ ID NO: 25, or a variant of SEQ ID NO: 25, wherein said variant differs from SEQ ID NO: 25 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acid wherein it differs from SEQ ID NO: 25; (iii) differs from SEQ ID NO: 25 in a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids, and / or (iv) comprises an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 25, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein the modified light chain variable region retains the CD45 specificity of the antibody (i.e., a specificity similar to Ab3), or has enhanced biological activity as compared to the biological activity of another Ab3 light chain variable region.

[0270] Antibodies comprising the CDR and / or variable region sequences of Ab3 may be in the form of full-length antibodies, bispecific antibodies, dual variable domain antibodies, multi-chain or single-chain antibodies, and / or binding fragments that specifically bind to human CD45, for example, but not limited to, Fab, Fab', (Fab')2, Fv, scFv (single-chain Fv), diabody (including constructs of surrogate light chains ), single domain antibodies, camelized antibodies, and the like. They may also be of any isotype (e.g., IgA (e.g., IgA1 or IgA2), IgD, IgE, IgG (e.g., , IgG1, IgG2, IgG3 or IgG4), or IgM, etc.), or may be derived therefrom. In some embodiments, the anti-CD45 antibody is IgG (e.g., IgG1, IgG2, IgG3 or IgG4).

[0271] In some embodiments, an antibody comprising the CDR and / or variable region sequence of Ab3 may further comprise a heavy chain constant region and / or a light chain constant region. In some embodiments, the constant region is a human IgG1 constant region, a human IgG2 constant region, a human IgG3 constant region, or a human IgG4 constant region. In some embodiments, the heavy chain constant region may be a modified constant region. Exemplary constant region substitutions and / or modifications include substitutions at one or more of the following positions: 234, 235 , 265, and 435 (EU index according to Kabat). In some embodiments, an antibody comprising the CDR and / or variable region sequence of Ab3 may further comprise an IgG1 heavy chain constant region comprising one or more of the following substitutions : L234A, L235A, D265C, and H435A (EU index according to Kabat). In some embodiments, an antibody comprising the CDR and / or variable region sequence of Ab3 may further comprise a heavy chain constant region as set forth in SEQ ID NO: 102, SEQ ID NO: 103, SEQ ID NO: 104, SEQ ID NO: 105 or SEQ ID NO: 106. In some embodiments, the antibody comprises a light chain constant region as set forth in SEQ ID NO: 101 .

[0272] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 29. In certain embodiments, the antibody It may include a modified heavy chain (HC) region that includes an HC domain containing SEQ ID NO: 29, or a variant of SEQ ID NO: 29, wherein said variant differs from SEQ ID NO: 29 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids; and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 29, where in any of (i)-(iv), the amino acid substitution can be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified heavy chain region retains the CD45 specificity of said antibody (i.e., a specificity similar to Ab3) or has enhanced biological activity compared to the biological activity of another Ab3 heavy chain region. or a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids; and (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 29, where in any of (i)-(iv), the amino acid substitution can be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified heavy chain region retains the CD45 specificity of said antibody (i.e., a specificity similar to Ab3) or has enhanced biological activity compared to the biological activity of another Ab3 heavy chain region. and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%,90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 29, where in any of (i)-(iv), the amino acid substitution can be a conservative amino acid substitution or a non-conservative amino acid substitution; and where said modified heavy chain region retains the CD45 specificity of said antibody (i.e., a specificity similar to Ab3) or has enhanced biological activity compared to the biological activity of another Ab3 heavy chain region. In certain embodiments, said anti-CD45 antibody, or antigen-binding portion thereof, includes a light chain that includes the amino acid sequence set forth in SEQ ID NO: 30. In certain embodiments, the antibody may include a modified light chain (LC) region that includes an LC domain containing SEQ ID NO: 30, or a variant of SEQ ID NO: 30, wherein said variant differs from SEQ ID NO: 30 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids;

[0273] In certain embodiments, said anti-CD45 antibody, or antigen-binding portion thereof, includes a light chain that includes the amino acid sequence set forth in SEQ ID NO: 30. In certain embodiments, the antibody may include a modified light chain (LC) region that includes an LC domain containing SEQ ID NO: 30, or a variant of SEQ ID NO: 30, wherein said variant differs from SEQ ID NO: 30 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; or a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or in the case of deletion, different from SEQ ID NO: 30; (iii) different from SEQ ID NO: 30 in substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids, and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 30, wherein in any of (i)-(iv), the amino acid substitution is a conservative amino acid substitution or a non-conservative amino acid substitution is fine; and wherein the modified light chain region retains the CD45 specificity of the antibody (i.e., the specificity similar to Ab3) or has enhanced biological activity compared to the biological activity of another Ab3 light chain region.

[0274] In some embodiments, antibodies comprising the CDR region and / or variable region of Ab3 may be incorporated into antibody-drug conjugates as described in this application. Further, antibodies comprising the CDR region and / or variable region of Ab3 may be used, for example, for the reduction of CD45 + cells in a subject, in the methods described in this application.

[0275] Ab4 Antibody 4 (Ab4) can cross-react with human CD45, cynomolgus monkey CD45 and rhesus monkey CD45 and can bind to various isoforms of human CD45.

[0276] The amino acid sequences of the various binding regions of anti-CD45 Ab4 are set forth in Table 27. For example, anti-CD45 antibodies based on Ab4 that include the CDRs set forth in Table 27 are included in the present invention.

[0277] ​​In one embodiment, the present invention provides an anti-CD45 antibody, or an antigen-binding fragment thereof, comprising an antigen-binding region corresponding to the antigen-binding region of Ab4, such as a CDR and / or variable region. The heavy chain variable region (VH) amino acid sequence of Ab4 is set forth in SEQ ID NO: 31 (see Table 27). The VH CDR domain amino acid sequences of Ab4 are set forth in SEQ ID NO: 32 (VH CDR1); SEQ ID NO: 33 (VH CDR2) and SEQ ID NO: 34 (VH CDR3). The light chain variable region (VL) amino acid sequence of Ab4 is set forth in SEQ ID NO: 35 (see Table 27). The VL CDR domain amino acid sequences of Ab4 are set forth in SEQ ID NO: 36 (VL CDR1); SEQ ID NO: 37 (VL CDR2) and SEQ ID NO: 38 (VL CDR3).

[0278] Accordingly, in some embodiments, the present application provides a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 32, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 33, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 34; and / or a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 36, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 37; and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 38, an anti-CD45 antibody, or an antigen-binding portion thereof. In certain embodiments, the anti-CD45 antibody comprises the CDRs described in the present application (SEQ ID Nos: 32 to 34 and 36 to 38), wherein the CDRs comprise conservative 1 amino acid substitutions (or 2, 3, 4, or 5 amino acid substitutions) while retaining the CD45 specificity of the antibody (i.e., a specificity similar to Ab4).

[0279] ​ In some embodiments, the present application provides an anti-CD45 antibody, or an antigen-binding portion thereof, comprising a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 31, and / or a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 35. In certain embodiments the antibody may comprise a modified heavy chain (HC) variable region comprising an HC variable domain comprising SEQ ID NO: 31, or a variant of SEQ ID NO: 31 wherein said variant differs from SEQ ID NO: 31 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids differing from SEQ ID NO: 31; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids differing from SEQ ID NO: 31, and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 31, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified heavy chain variable region retains the CD45 specificity of said antibody (i.e., a specificity similar to Ab4), or has enhanced biological activity compared to the biological activity of another Ab4 heavy chain variable region. In certain embodiments, the antibody comprises a modified light chain (LC) variable region comprising an LC variable domain comprising SEQ ID NO: 35, or a variant of SEQ ID NO: 35, wherein said variant differs from SEQ ID NO: 35 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acid substitutions, additions or deletions; wherein it differs from SEQ ID NO: 35; (iii) in a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids, it differs from SEQ ID NO: 35, and / or (iv) it comprises an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 35, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein the modified light chain variable region retains the CD45 specificity of the antibody (i.e., the specificity similar to Ab4), or has enhanced biological activity as compared to the biological activity of another Ab4 light chain variable region.

[0280] Antibodies comprising the CDR and / or variable region sequences of Ab4 may be in the form of full-length antibodies, bispecific antibodies, dual variable domain antibodies, multi-chain or single-chain antibodies, and / or binding fragments that specifically bind to human CD45, for example, but not limited to, Fab, Fab', (Fab')2, Fv, scFv (single-chain Fv), salobody (including constructs of surrogate light chains ), single domain antibodies, camelized antibodies, etc. They may also be of any isotype (e.g., IgA (e.g., IgA1 or IgA2), IgD, IgE, IgG (e.g., , IgG1, IgG2, IgG3 or IgG4), or IgM, etc.), or may be derived therefrom. In some embodiments, the anti-CD45 antibody is IgG (e.g., IgG1, IgG2, IgG3 or IgG4).

[0281] In some embodiments, an antibody comprising the CDR and / or variable region sequence of Ab4 may further comprise a heavy chain constant region and / or a light chain constant region. In some embodiments, the constant region is a human IgG1 constant region, a human IgG2 constant region, a human IgG3 constant region, or a human IgG4 constant region. In some embodiments, the heavy chain constant region may be a modified constant region. Exemplary constant region substitutions and / or modifications include substitutions at one or more of the following positions: 234, 235 , 265, and 435 (EU index according to Kabat). In some embodiments, an antibody comprising the CDR and / or variable region sequence of Ab4 may further comprise an IgG1 heavy chain constant region comprising one or more of the following substitutions: L234A, L235A, D265C, and H435A (EU index according to Kabat). In some embodiments, an antibody comprising the CDR and / or variable region sequence of Ab4 may further comprise a heavy chain constant region as set forth in SEQ ID NO: 102, SEQ ID NO: 103, SEQ ID NO: 104, SEQ ID NO: 105 or SEQ ID NO: 106. In some embodiments, the antibody comprises a light chain constant region as set forth in SEQ ID NO: 101. In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ

[0282] ID NO: 39. In certain embodiments, the antibody comprises a heavy chain comprising the amino acid sequence set forth in SEQ It may include a modified heavy chain (HC) region containing an HC domain that includes SEQ ID NO: 39, or a variant of SEQ ID NO: 39. This variant (i) differs from SEQ ID NO: 39 in 1, 2, 3, 4, or 5 amino acid substitutions, additions, or deletions; (ii) differs from SEQ ID NO: 39 in at most 5, 4, 3, 2, or 1 amino acid substitutions, additions, or deletions; (iii) differs from SEQ ID NO: 39 in 1-5, 1-3, 1-2, 2-5, or 3-5 amino acid substitutions, additions, or deletions; and / or (iv) includes an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to SEQ ID NO: 39. Here, in any of (i)-(iv), the amino acid substitution can be a conservative amino acid substitution or a non-conservative amino acid substitution. And here, the modified heavy chain region retains the CD45 specificity of the antibody (i.e., a specificity similar to Ab4), or has enhanced biological activity compared to the biological activity of another Ab4 heavy chain region.

[0283] In certain embodiments, the anti-CD45 antibody, or an antigen-binding portion thereof, includes a light chain that includes the amino acid sequence set forth in SEQ ID NO: 40. In certain embodiments, the antibody may include a modified light chain (LC) region containing an LC domain that includes SEQ ID NO: 40, or a variant of SEQ ID NO: 40. This variant (i) differs from SEQ ID NO: 40 in 1, 2, 3, 4, or 5 amino acid substitutions, additions, or deletions; (ii) differs from SEQ ID NO: 40 in at most 5, 4, 3, 2, or 1 amino acid substitutions, additions, or in a deletion, different from SEQ ID NO: 40; (iii) in a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids, different from SEQ ID NO: 40, and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 40, wherein in any of (i)-(iv), the amino acid substitution is a conservative amino acid substitution or a non-conservative amino acid substitution, is good; and wherein the modified light chain region retains the CD45 specificity of the antibody (i.e., a specificity similar to Ab4) or has enhanced biological activity compared to the biological activity of another Ab4 light chain region.

[0284] In some embodiments, an antibody comprising the CDR region and / or variable region of Ab4 may be incorporated into an antibody-drug conjugate as described in this application. Further, an antibody comprising the CDR region and / or variable region of Ab4 may be used, for example, for the reduction of CD45+ cells in a subject, in the methods described in this application.

[0285] Ab5 Antibody 5 (Ab5) can cross-react with human CD45, cynomolgus monkey CD45 and rhesus monkey CD45 and can bind to various isoforms of human CD45.

[0286] The amino acid sequences of the various binding regions of anti-CD45 Ab5 are set forth in Table 27. For example, anti-CD45 antibodies based on Ab5 that contain the CDRs set forth in Table 27 are included in the present invention. are included in the present invention.

[0287] In one embodiment, the present invention provides an anti-CD45 antibody, or an antigen-binding fragment thereof, comprising an antigen-binding region corresponding to the antigen-binding region of Ab5, such as a CDR and / or variable region. The heavy chain variable region (VH) amino acid sequence of Ab5 is set forth in SEQ ID NO: 41 (see Table 27). The VH CDR domain amino acid sequences of Ab5 are set forth in SEQ ID NO: 42 (VH CDR1); SEQ ID NO: 43 (VH CDR2) and SEQ ID NO: 44 (VH CDR3). The light chain variable region (VL) amino acid sequence of Ab5 is set forth in SEQ ID NO: 45 (see Table 27). The VL CDR domain amino acid sequences of Ab5 are set forth in SEQ ID NO: 46 (VL CDR1); SEQ ID NO: 47 (VL CDR2) and SEQ ID NO: 48 (VL CDR3).

[0288] Accordingly, in some embodiments, the present application provides a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 42, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 43, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 44; and / or a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 46, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 47; and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 48, comprising an anti-CD45 antibody, or an antigen-binding portion thereof. In certain embodiments, the anti-CD45 antibody comprises the CDRs described in the present application (SEQ ID Nos: 42 to 44 and 46 to 48), wherein the CDRs contain conservative 1 amino acid substitution (or 2, 3, 4, or 5 amino acid substitutions) while retaining the CD45 specificity of the antibody (i.e., specificity similar to Ab5).

[0289] ​​ In some embodiments, the present application provides an anti-CD45 antibody, or an antigen-binding portion thereof, comprising a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 41 and / or a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 45. In certain embodiments the antibody may comprise a modified heavy chain (HC) variable region comprising an HC variable domain comprising SEQ ID NO: 41, or a variant of SEQ ID NO: 41, wherein said variant differs from SEQ ID NO: 41 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids; and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 41, where in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified heavy chain variable region retains the CD45 specificity of the antibody (i.e., a specificity similar to Ab5) or has enhanced biological activity as compared to the biological activity of another Ab5 heavy chain variable region. In certain embodiments, the antibody comprises a modified light chain (LC) variable region comprising an LC variable domain comprising SEQ ID NO: 45, or a variant of SEQ ID NO: 45, wherein said variant differs from SEQ ID NO: 45 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acid; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids; and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 45, where in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified light chain variable region retains the CD45 specificity of the antibody (i.e., a specificity similar to Ab5) or has enhanced biological activity as compared to the biological activity of another Ab5 light chain variable region. In certain embodiments, the antibody comprises a modified light chain (LC) variable region comprising an LC variable domain comprising SEQ ID NO: 45, or a variant of SEQ ID NO: 45, wherein said variant differs from SEQ ID NO: 45 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids; and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 45, where in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified light chain variable region retains the CD45 specificity of the antibody (i.e., a specificity similar to Ab5) or has enhanced biological activity as compared to the biological activity of another Ab5 light chain variable region. In certain embodiments, the antibody comprises a modified light chain (LC) variable region comprising an LC variable domain comprising SEQ ID NO: 45, or a variant of SEQ ID NO: 45, wherein said variant differs from SEQ ID NO: 45 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids; and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 45, where in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified light chain variable region retains the CD45 specificity of the antibody (i.e., a specificity similar to Ab5) or has enhanced biological activity as compared to the biological activity of another Ab5 light chain variable region. wherein it differs from SEQ ID NO: 45; (iii) in a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids, it differs from SEQ ID NO: 45, and / or (iv) it comprises an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 45, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein the modified light chain variable region retains the CD45 specificity of the antibody (i.e., a specificity similar to Ab5), or has enhanced biological activity as compared to the biological activity of another Ab5 light chain variable region.

[0290] Antibodies comprising the CDR and / or variable region sequence of Ab5 may be in the form of a full-length antibody, a bispecific antibody, a dual variable domain antibody, a multi-chain or single-chain antibody, and / or a binding fragment that specifically binds to human CD45, for example, but not limited to, Fab, Fab', (Fab')2, Fv, scFv (single-chain Fv), a sarobody (comprising a surrogate light chain construct), a single domain antibody, a camelized antibody, etc. They may also be of any isotype (e.g., IgA (e.g., IgA1 or IgA2), IgD, IgE, IgG (e.g., , IgG1, IgG2, IgG3 or IgG4), or IgM, etc.), or may be derived therefrom. In some embodiments, the anti-CD45 antibody is IgG (e.g., IgG1, IgG2, IgG3 or IgG4).

[0291] In some embodiments, the antibody comprising the CDR and / or variable region sequence of Ab5 further comprises a heavy chain It may include a constant region and / or a light chain constant region. In some embodiments, the constant region is a human IgG1 constant region, a human IgG2 constant region, a human IgG3 constant region, or a human IgG4 constant region. In some embodiments, the heavy chain constant region may be a modified constant region. Exemplary constant region substitutions and / or modifications include substitutions at one or more of the following positions as described in this application and are not limited to: 234, 235 , 265, and 435 (EU index according to Kabat). In some embodiments, an antibody comprising the CDR of Ab5 and / or variable region sequence may further comprise an IgG1 heavy chain constant region comprising one or more of the following substitutions: L234A, L235A, D265C, and H435A (EU index according to Kabat). In some embodiments, an antibody comprising the CDR of Ab5 and / or variable region sequence may further comprise a heavy chain constant region as set forth in SEQ ID NO: 102, SEQ ID NO: 103, SEQ ID NO: 104, SEQ ID ID NO: 105 or SEQ ID NO: 106. In some embodiments, the antibody comprises a light chain constant region as set forth in SEQ ID NO: 101 . In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 49. In certain embodiments, the antibody may comprise a modified heavy chain (HC) region comprising an HC domain comprising SEQ ID NO: 49, or a variant of SEQ ID NO: 49, wherein the variant is (i) different from SEQ ID NO: 49 in 1, 2, 3, 4 or 5 amino acid substitutions, additions or deletions; (ii) at most 5, 4, 3, 2 or 1 amino acid substitutions, additions or

[0292] deletions; In certain embodiments, the antibody may comprise a modified heavy chain (HC) region comprising an HC domain comprising SEQ ID NO: 49, or a variant of SEQ ID NO: 49, wherein the variant is (i) different from SEQ ID NO: 49 in 1, 2, 3, 4 or 5 amino acid substitutions, additions or deletions; (ii) at most 5, 4, 3, 2 or 1 amino acid substitutions, additions or deletions; in a deletion, different from SEQ ID NO: 49; (iii) in a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids, different from SEQ ID NO: 49, and / or (iv) comprising an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 49, wherein in any of (i)-(iv), the amino acid substitution is a conservative amino acid substitution or a non-conservative amino acid substitution, is good; and wherein the modified heavy chain region retains the CD45 specificity of the antibody (i.e., a specificity similar to Ab5) or has enhanced biological activity compared to the biological activity of another Ab5 heavy chain region.

[0293] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 50. In certain embodiments, the antibody may comprise a modified light chain (LC) region comprising an LC domain comprising SEQ ID NO: 50 or a variant of SEQ ID NO: 50, wherein the variant is (i) different from SEQ ID NO: 50 in a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) different from SEQ ID NO: 50 in a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; (iii) in a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids, different from SEQ ID NO: 50, and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:50, wherein in any of (i)-(iv), the amino acid substitution is either a conservative amino acid substitution or a non-conservative amino acid substitution Good; and wherein said modified light chain region retains the CD45 specificity of said antibody (i.e., a specificity similar to Ab5) or has enhanced biological activity as compared to the biological activity of another Ab5 light chain region.

[0294] In some embodiments, an antibody comprising the CDR region and / or variable region of Ab5 may be incorporated into an antibody-drug conjugate as described in this application. Further, an antibody comprising the CDR region and / or variable region of Ab5 may be used, for example, for the reduction of CD45+ cells in a subject in the methods described in this application.

[0295] Ab6 Antibody 6 (Ab6) can cross-react with human CD45, cynomolgus monkey CD45 and rhesus monkey CD45 and can bind to various isoforms of human CD45.

[0296] The amino acid sequences of the various binding regions of anti-CD45 Ab6 are set forth in Table 27. For example, an anti-CD45 antibody based on Ab6 that includes the CDRs set forth in Table 27 is included in the present invention. In one embodiment, the present invention provides an anti-CD45 antibody, or an antigen-binding fragment thereof, comprising an antigen-binding region corresponding to the antigen-binding region of Ab6, such as the CDR and / or variable region. The amino acid sequence of the heavy chain variable region (VH) of Ab6 is set forth in SEQ ID NO:51 (see Table 27). The amino acid sequence of the VH CDR domain of Ab6 is set forth in SEQ ID NO:52 (VH CDR1); SEQ

[0297] ​The numbers (SEQ ID NO): 53 (VH CDR2) and sequence number (SEQ ID NO): 54 (VH CDR3), are described in Ab6. The light chain variable region (VL) amino acid sequence of is described in sequence number (SEQ ID NO): 55 (see Table 27). The VL CDR domain amino acid sequences of Ab6 are described in sequence number (SEQ ID NO): 56 (VL CDR1); sequence number (SEQ ID NO): 57 (VL CDR2) and sequence number (SEQ ID NO): 58 (VL CDR3).

[0298] Accordingly, in some embodiments, the present application provides a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in sequence number (SEQ ID NO): 52, a CDR2 domain comprising the amino acid sequence set forth in sequence number (SEQ ID NO): 53, and a CDR3 domain comprising the amino acid sequence set forth in sequence number (SEQ ID NO): 54; and / or a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in sequence number (SEQ ID NO): 56, a CDR2 domain comprising the amino acid sequence set forth in sequence number (SEQ ID NO): 57; and a CDR3 domain comprising the amino acid sequence set forth in sequence number (SEQ ID NO): 58. An anti-CD45 antibody, or an antigen-binding portion thereof, is provided. In certain embodiments, the anti-CD45 antibody comprises the CDRs described in the present application (sequence numbers (SEQ ID Nos): 52 to 54 and 56 to 58), wherein the CDRs comprise conservative 1 amino acid substitution (or 2, 3, 4, or 5 amino acid substitutions) while retaining the CD45 specificity of the antibody (i.e., specificity similar to Ab6).

[0299] In some embodiments, the present application provides an anti-CD45 antibody, or an antigen-binding portion thereof, comprising a heavy chain variable region comprising the amino acid sequence set forth in sequence number (SEQ ID NO): 51, and / or a light chain variable region comprising the amino acid sequence set forth in sequence number (SEQ ID NO): 55. In certain embodiments In one form, the antibody may comprise a modified heavy chain (HC) variable region comprising an HC variable domain comprising SEQ ID NO: 51, or a variant of SEQ ID NO: 51, wherein said variant (i) differs from SEQ ID NO: 51 in a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) differs from SEQ ID NO: 51 in a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acid; (iii) differs from SEQ ID NO: 51 in a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids, and / or (iv) comprises an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 51, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified heavy chain variable region retains the CD45 specificity of said antibody (i.e., a specificity similar to Ab6) or has enhanced biological activity compared to the biological activity of another Ab6 heavy chain variable region. In certain embodiments, the antibody comprises a modified light chain (LC) variable region comprising an LC variable domain comprising SEQ ID NO: 55, or a variant of SEQ ID NO: 55, wherein said variant (i) differs from SEQ ID NO: 55 in a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) differs from SEQ ID NO: 55 in a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acid acid; (iii) differs from SEQ ID NO: 55 in a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids, and / or (iv) comprises an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 55, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified light chain variable region retains the CD45 specificity of said antibody (i.e., a specificity similar to Ab6) or has enhanced biological activity compared to the biological activity of another Ab6 light chain variable region. In certain embodiments, the antibody comprises a modified light chain (LC) variable region comprising an LC variable domain comprising SEQ ID NO: 55, or a variant of SEQ ID NO: 55, wherein said variant (i) differs from SEQ ID NO: 55 in a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) differs from SEQ ID NO: 55 in a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acid acid; (iii) differs from SEQ ID NO: 55 in a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids, and / or (iv) comprises an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 55, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified light chain variable region retains the CD45 specificity of said antibody (i.e., a specificity similar to Ab6) or has enhanced biological activity compared to the biological activity of another Ab6 light chain variable region. In certain embodiments, the antibody comprises a modified light chain (LC) variable region comprising an LC variable domain comprising SEQ ID NO: 55, or a variant of SEQ ID NO: 55, wherein said variant (i) differs from SEQ ID NO: 55 in a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) differs from SEQ ID NO: 55 in a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acid acid; (iii) differs from SEQ ID NO: 55 in a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids, and / or (iv) comprises an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 55, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified light chain variable region retains the CD45 specificity of said antibody (i.e., a specificity similar to Ab6) or has enhanced biological activity compared to the biological activity of another Ab6 light chain variable region. In certain embodiments, the antibody comprises a modified light chain (LC) variable region comprising an LC variable domain comprising SEQ ID NO: 55, or a variant of SEQ ID NO: 55, wherein said variant (i) differs from SEQ ID NO: 55 in a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) differs from SEQ ID NO: 55 in a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acid wherein it differs from SEQ ID NO: 55; (iii) differs from SEQ ID NO: 55 in a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids, and / or (iv) comprises an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 55, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein the modified light chain variable region retains the CD45 specificity of the antibody (i.e., the specificity similar to Ab6), or has enhanced biological activity as compared to the biological activity of another Ab6 light chain variable region.

[0300] Antibodies comprising the CDR and / or variable region sequences of Ab6 may be in the form of full-length antibodies, bispecific antibodies, dual variable domain antibodies, multi-chain or single-chain antibodies, and / or binding fragments that specifically bind to human CD45, for example, but not limited to, Fab, Fab', (Fab')2, Fv, scFv (single-chain Fv), diabody (comprising a surrogate light chain construct), single domain antibody, camelized antibody, etc. They may also be of any isotype (e.g., IgA (e.g., IgA1 or IgA2), IgD, IgE, IgG (e.g. , IgG1, IgG2, IgG3 or IgG4), or IgM, etc.), or may be derived therefrom. In some embodiments, the anti-CD45 antibody is IgG (e.g., IgG1, IgG2, IgG3 or IgG4).

[0301] In some embodiments, an antibody comprising the CDR and / or variable region sequence of Ab6 may further comprise a heavy chain constant region and / or a light chain constant region. In some embodiments, the constant region is a human IgG1 constant region, a human IgG2 constant region, a human IgG3 constant region, or a human IgG4 constant region. In some embodiments, the heavy chain constant region may be a modified constant region. Exemplary constant region substitutions and / or modifications include substitutions at one or more of the following positions: 234, 235 , 265, and 435 (EU index according to Kabat). In some embodiments, an antibody comprising the CDR and / or variable region sequence of Ab6 may further comprise an IgG1 heavy chain constant region comprising one or more of the following substitutions: L234A, L235A, D265C, and H435A (EU index according to Kabat). In some embodiments, an antibody comprising the CDR and / or variable region sequence of Ab6 may further comprise a heavy chain constant region as set forth in SEQ ID NO: 102, SEQ ID NO: 103, SEQ ID NO: 104, SEQ ID NO: 105 or SEQ ID NO: 106. In some embodiments, the antibody comprises a light chain constant region as set forth in SEQ ID NO: 101 .

[0302] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 59. In certain embodiments, the antibody may include a modified heavy chain (HC) region that includes an HC domain comprising SEQ ID NO: 59, or a variant of SEQ ID NO: 59, wherein said variant differs from SEQ ID NO: 59 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids; and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 59, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified heavy chain region retains the CD45 specificity of said antibody (i.e., a specificity similar to Ab6) or has enhanced biological activity as compared to the biological activity of another Ab6 heavy chain region. or a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids; and (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 59, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution. In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, includes a light chain comprising the amino acid sequence set forth in SEQ ID NO: 60. In certain embodiments, the antibody may include a modified light chain (LC) region that includes an LC domain comprising SEQ ID NO: 60, or a variant of SEQ ID NO: 60, wherein said variant differs from SEQ ID NO: 60 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids;

[0303] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, includes a light chain comprising the amino acid sequence set forth in SEQ ID NO: 60. In certain embodiments, the antibody may include a modified light chain (LC) region that includes an LC domain comprising SEQ ID NO: 60, or a variant of SEQ ID NO: 60, wherein said variant differs from SEQ ID NO: 60 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or in the case of deletion, different from SEQ ID NO: 60; (iii) different from SEQ ID NO: 60 in 1 - 5, 1 - 3, 1 - 2, 2 - 5 or 3 - 5 amino acid substitutions, additions or deletions; and / or (iv) comprising an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 60, wherein in any of (i) - (iv), the amino acid substitution may be a conservative amino acid substitution or a non - conservative amino acid substitution is good; and wherein the modified light chain region retains the CD45 specificity of the antibody (i.e., the specificity similar to Ab6) or has enhanced biological activity compared to the biological activity of another Ab6 light chain region.

[0304] In some embodiments, an antibody comprising the CDR region and / or variable region of Ab6 may be incorporated into an antibody - drug conjugate as described in this application. Further, an antibody comprising the CDR region and / or variable region of Ab6 may be used, for example, for the reduction of CD45 + cells in a subject, in the methods described in this application.

[0305] Ab7 Antibody 7 (Ab7) can cross - react with human CD45, cynomolgus monkey CD45 and rhesus monkey CD45 and can bind to various isoforms of human CD45.

[0306] The amino acid sequences of various binding regions of anti - CD45 Ab7 are listed in Table 27. For example, an anti - CD45 antibody based on Ab7 containing the CDRs listed in Table 27 is included in the present invention. is included in the present invention.

[0307] In one embodiment, the present invention provides an anti-CD45 antibody, or an antigen-binding fragment thereof, comprising an antigen-binding region corresponding to the antigen-binding region of Ab7, such as a CDR and / or variable region. The heavy chain variable region (VH) amino acid sequence of Ab7 is set forth in SEQ ID NO: 61 (see Table 27). The VH CDR domain amino acid sequences of Ab7 are set forth in SEQ ID NO: 62 (VH CDR1); SEQ ID NO: 63 (VH CDR2) and SEQ ID NO: 64 (VH CDR3). The light chain variable region (VL) amino acid sequence of Ab7 is set forth in SEQ ID NO: 65 (see Table 27). The VL CDR domain amino acid sequences of Ab7 are set forth in SEQ ID NO: 66 (VL CDR1); SEQ ID NO: 67 (VL CDR2) and SEQ ID NO: 68 (VL CDR3). Accordingly, in some embodiments, the present application provides a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 62, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 63, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 64; and / or a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 66, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 67; and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 68,

[0308] comprising an anti-CD45 antibody, or an antigen-binding portion thereof. In certain embodiments, the anti-CD45 antibody comprises the CDRs described in the present application (SEQ ID Nos: 62 to 64 and 66 to 68), wherein the CDRs contain conservative 1 amino acid substitutions (or 2, 3, 4, or 5 amino acid substitutions) while retaining the CD45 specificity of the antibody (i.e., a specificity similar to Ab7). In certain embodiments, the anti-CD45 antibody comprises the CDRs described in the present application (SEQ ID Nos: 62 to 64 and 66 to 68), wherein the CDRs contain conservative 1 amino acid substitutions (or 2, 3, 4, or 5 amino acid substitutions) while retaining the CD45 specificity of the antibody (i.e., a specificity similar to Ab7).

[0309] In some embodiments, the present application provides an anti-CD45 antibody, or antigen-binding portion thereof, comprising a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 61 and / or a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 65. In some embodiments, the antibody may comprise a modified heavy chain (HC) variable region comprising an HC variable domain comprising SEQ ID NO:61, or a variant of SEQ ID NO:61, wherein the variant (i) differs from SEQ ID NO:61 in the substitution, addition, or deletion of 1, 2, 3, 4, or 5 amino acids; (ii) differs from SEQ ID NO:61 in the substitution, addition, or deletion of at most 5, 4, 3, 2, or 1 amino acids; (iii) differs from SEQ ID NO:61 in 1-5, 1-3, 1-2, 2-5, or 3-5 amino acid substitutions, additions, or deletions; and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to SEQ ID NO: 61, wherein in any of (i)-(iv), the amino acid substitutions may be conservative amino acid substitutions or non-conservative amino acid substitutions. and wherein the modified heavy chain variable region retains the CD45 specificity of the antibody (i.e., Ab7-like specificity) or has enhanced biological activity compared to the biological activity of another Ab7 heavy chain variable region. In certain embodiments, the antibody comprises a modified light chain (LC) variable region comprising an LC variable domain comprising SEQ ID NO:65, or a variant of SEQ ID NO:65, where the variant differs from SEQ ID NO:65 by (i) 1, 2, 3, 4, or 5 amino acid substitutions, additions, or deletions; or (ii) at most 5, 4, 3, 2, or 1 amino acid substitutions, additions, or deletions. wherein it differs from SEQ ID NO: 65; (iii) differs from SEQ ID NO: 65 in a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids, and / or (iv) comprises an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 65, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein the modified light chain variable region retains the CD45 specificity of the antibody (i.e., the specificity similar to Ab7), or has enhanced biological activity as compared to the biological activity of another Ab7 light chain variable region.

[0310] Antibodies comprising the CDR and / or variable region sequences of Ab7 may be in the form of full-length antibodies, bispecific antibodies, dual variable domain antibodies, multi-chain or single-chain antibodies, and / or binding fragments that specifically bind to human CD45, for example, but not limited to, Fab, Fab', (Fab')2, Fv, scFv (single-chain Fv), diabody (including constructs of surrogate light chains ), single domain antibodies, camelized antibodies, and the like. They may also be of any isotype (e.g., IgA (e.g., IgA1 or IgA2), IgD, IgE, IgG (e.g. , IgG1, IgG2, IgG3 or IgG4), or IgM, etc.), or may be derived therefrom. In some embodiments, the anti-CD45 antibody is IgG (e.g., IgG1, IgG2, IgG3 or IgG4).

[0311] In some embodiments, an antibody comprising the CDR and / or variable region sequence of Ab7 may further comprise a heavy chain constant region and / or a light chain constant region. In some embodiments, the constant region is a human IgG1 constant region, a human IgG2 constant region, a human IgG3 constant region, or a human IgG4 constant region. In some embodiments, the heavy chain constant region may be a modified constant region. Exemplary constant region substitutions and / or modifications include substitutions at one or more of the following positions: 234, 235 , 265, and 435 (EU index according to Kabat). In some embodiments, an antibody comprising the CDR and / or variable region sequence of Ab7 may further comprise an IgG1 heavy chain constant region comprising one or more of the following substitutions: L234A, L235A, D265C, and H435A (EU index according to Kabat). In some embodiments, an antibody comprising the CDR and / or variable region sequence of Ab7 may further comprise a heavy chain constant region as set forth in SEQ ID NO: 102, SEQ ID NO: 103, SEQ ID NO: 104, SEQ ID NO: 105, or SEQ ID NO: 106. In some embodiments, the antibody comprises a light chain constant region as set forth in SEQ ID NO: 101 .

[0312] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 69. In certain embodiments, the antibody may include a modified heavy chain (HC) region that includes an HC domain that includes SEQ ID NO: 69, or a variant of SEQ ID NO: 69, wherein said variant differs from SEQ ID NO: 69 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids; and / or (iv) includes an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 69, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified heavy chain region retains the CD45 specificity of said antibody (i.e., a specificity similar to Ab7) or has enhanced biological activity compared to the biological activity of another Ab7 heavy chain region. or a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids; and (iv) includes an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 69, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution. In certain embodiments, said anti-CD45 antibody, or antigen-binding portion thereof, includes a light chain that includes the amino acid sequence set forth in SEQ ID NO: 70. In certain embodiments, the antibody may include a modified light chain (LC) region that includes an LC domain that includes SEQ ID NO: 70, or a variant of SEQ ID NO: 70, wherein said variant differs from SEQ ID NO: 70 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids;

[0313] In certain embodiments, the antibody or antigen-binding portion thereof includes a light chain that includes the amino acid sequence set forth in SEQ ID NO: 70. In certain embodiments, the antibody may include a modified light chain (LC) region that includes an LC domain that includes SEQ ID NO: 70, or a variant of SEQ ID NO: 70, wherein said variant differs from SEQ ID NO: 70 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; in a deletion, different from SEQ ID NO: 70; (iii) in a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids, different from SEQ ID NO: 70, and / or (iv) comprising an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 70, wherein in any of (i)-(iv), the amino acid substitution can be a conservative amino acid substitution or a non-conservative amino acid substitution, is good; and wherein the modified light chain region retains the CD45 specificity of the antibody (i.e., a specificity similar to Ab7) or has enhanced biological activity compared to the biological activity of another Ab7 light chain region.

[0314] In some embodiments, an antibody comprising the CDR region and / or variable region of Ab7 may be incorporated into an antibody-drug conjugate as described in this application. Further, an antibody comprising the CDR region and / or variable region of Ab7 may be used, for example, for the reduction of CD45+ cells in a subject, in the methods described in this application.

[0315] AbA Antibody A (AbA) can cross-react with human CD45, cynomolgus monkey CD45 and rhesus monkey CD45 and can bind to various isoforms of human CD45.

[0316] The amino acid sequences of various binding regions of anti-CD45 AbA are set forth in Table 27. For example, anti-CD45 antibodies based on AbA that contain the CDRs set forth in Table 27 are included in the present invention. are included in the present invention.

[0317] In one embodiment, the present invention provides an anti-CD45 antibody, or an antigen-binding fragment thereof, comprising an antigen-binding region corresponding to the antigen-binding region of AbA, such as a CDR and / or variable region. The amino acid sequence of the heavy chain variable region (VH) of AbA is set forth in SEQ ID NO: 71 (see Table 27). The amino acid sequences of the VH CDR domain of AbA are set forth in SEQ ID NO: 72 (VH CDR1); SEQ ID NO: 73 (VH CDR2) and SEQ ID NO: 74 (VH CDR3). The amino acid sequence of the light chain variable region (VL) of AbA is set forth in SEQ ID NO: 75 (see Table 27). The amino acid sequences of the VL CDR domain of AbA are set forth in SEQ ID NO: 76 (VL CDR1); SEQ ID NO: 77 (VL CDR2) and SEQ ID NO: 78 (VL CDR3).

[0318] Accordingly, in some embodiments, the present application provides a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 72, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 73, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 74; and / or a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 76, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 77; and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 78, of a light chain variable region, comprising an anti-CD45 antibody, or an antigen-binding portion thereof. In certain embodiments, the anti-CD45 antibody comprises the CDRs described in the present application (SEQ ID Nos: 72 to 74 and 76 to 78), wherein the CDRs comprise conservative 1 amino acid substitution (or 2, 3, 4, or 5 amino acid substitutions) while retaining the CD45 specificity of the antibody (i.e., specificity similar to AbA). ​​

[0319] In some embodiments, the present application provides an anti-CD45 antibody, or antigen-binding portion thereof, comprising a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 71 and / or a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 75. In some embodiments, the antibody may comprise a modified heavy chain (HC) variable region comprising an HC variable domain comprising SEQ ID NO:71, or a variant of SEQ ID NO:71, wherein the variant (i) differs from SEQ ID NO:71 in the substitution, addition, or deletion of 1, 2, 3, 4, or 5 amino acids; (ii) differs from SEQ ID NO:71 in the substitution, addition, or deletion of at most 5, 4, 3, 2, or 1 amino acids; (iii) differs from SEQ ID NO: 71 in 1-5, 1-3, 1-2, 2-5, or 3-5 amino acid substitutions, additions, or deletions; and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to SEQ ID NO: 71, wherein in any of (i)-(iv), the amino acid substitutions may be conservative amino acid substitutions or non-conservative amino acid substitutions. and wherein the modified heavy chain variable region retains the CD45 specificity of the antibody (i.e., specificity similar to AbA) or has enhanced biological activity compared to the biological activity of another AbA heavy chain variable region. In certain embodiments, the antibody comprises a modified light chain (LC) variable region comprising an LC variable domain comprising SEQ ID NO:75, or a variant of SEQ ID NO:75, where the variant differs from SEQ ID NO:75 by (i) 1, 2, 3, 4, or 5 amino acid substitutions, additions, or deletions; or (ii) at most 5, 4, 3, 2, or 1 amino acid substitutions, additions, or deletions. wherein (i) is different from SEQ ID NO: 75; (iii) is different from SEQ ID NO: 75 in substitutions, additions or deletions of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids, and / or (iv) comprises an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 75, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein the modified light chain variable region retains the CD45 specificity of the antibody (i.e., the specificity similar to AbA), or has enhanced biological activity as compared to the biological activity of another AbA light chain variable region.

[0320] Antibodies comprising the CDR and / or variable region sequences of AbA may be in the form of full-length antibodies, bispecific antibodies, dual variable domain antibodies, multi-chain or single-chain antibodies, and / or binding fragments that specifically bind to human CD45, for example, but not limited to, Fab, Fab', (Fab')2, Fv, scFv (single-chain Fv), sarobody (including constructs of surrogate light chains ), single domain antibodies, camelized antibodies, and the like. They may also be of any isotype (e.g., IgA (e.g., IgA1 or IgA2), IgD, IgE, IgG (e.g., , IgG1, IgG2, IgG3 or IgG4), or IgM, etc.), or may be derived from. In some embodiments, the anti-CD45 antibody is IgG (e.g., IgG1, IgG2, IgG3 or IgG4).

[0321] In some embodiments, an antibody comprising the CDR and / or variable region sequence of AbA may further comprise a heavy chain constant region and / or a light chain constant region. In some embodiments, the constant region is a human IgG1 constant region, a human IgG2 constant region, a human IgG3 constant region, or a human IgG4 constant region. In some embodiments, the heavy chain constant region may be a modified constant region. Exemplary constant region substitutions and / or modifications include substitutions at one or more of the following positions: 234, 235 , 265, and 435 (EU index according to Kabat). In some embodiments, an antibody comprising the CDR and / or variable region sequence of AbA may further comprise an IgG1 heavy chain constant region comprising one or more of the following substitutions: L234A, L235A, D265C, and H435A (EU index according to Kabat). In some embodiments, an antibody comprising the CDR and / or variable region sequence of AbA may further comprise a heavy chain constant region described in SEQ ID NO: 102, SEQ ID NO: 103, SEQ ID NO: 104, SEQ ID NO: 105 or SEQ ID NO: 106. In some embodiments, the antibody comprises a light chain constant region described in SEQ ID NO: 101. In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence described in SEQ ID NO: 79. In certain embodiments, the antibody

[0322] ​It may include a modified heavy chain (HC) region that includes an HC domain comprising SEQ ID NO: 79, or a variant of SEQ ID NO: 79, wherein said variant (i) differs from SEQ ID NO: 79 in a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) differs from SEQ ID NO: 79 in at most 5, 4, 3, 2 or 1 amino acid substitutions, additions or deletions; (iii) differs from SEQ ID NO: 79 in a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids; and / or (iv) comprises an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 79, wherein in any of (i)-(iv), the amino acid substitution can be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified heavy chain region retains the CD45 specificity of said antibody (i.e., specificity similar to AbA) or has enhanced biological activity compared to the biological activity of another AbA heavy chain region. In certain embodiments, said anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 80. In certain embodiments, the antibody may include a modified light chain (LC) region that includes an LC domain comprising SEQ ID NO: 80, or a variant of SEQ ID NO: 80, wherein said variant (i) differs from SEQ ID NO: 80 in a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) differs from SEQ ID NO: 80 in at most 5, 4, 3, 2 or 1 amino acid substitutions, additions or

[0323] In certain embodiments, the antibody may include a modified light chain (LC) region that includes an LC domain comprising SEQ ID NO: 80, or a variant of SEQ ID NO: 80, wherein said variant (i) differs from SEQ ID NO: 80 in a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) differs from SEQ ID NO: 80 in at most 5, 4, 3, 2 or 1 amino acid substitutions, additions or in the case of deletion, different from SEQ ID NO: 80; (iii) in substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids, different from SEQ ID NO: 80, and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 80, wherein in any of (i)-(iv), the amino acid substitution is a conservative amino acid substitution or a non-conservative amino acid substitution, is good; and wherein the modified light chain region retains the CD45 specificity of the antibody (i.e., the specificity similar to AbA) or has enhanced biological activity compared to the biological activity of another AbA light chain region.

[0324] In some embodiments, an antibody comprising the CDR region and / or variable region of AbA may be incorporated into an antibody-drug conjugate as described in this application. Further, an antibody comprising the CDR region and / or variable region of AbA may be used, for example, for the reduction of CD45+ cells in a subject, in the methods described in this application.

[0325] AbB Antibody B (AbB) can cross-react with human CD45, cynomolgus monkey CD45 and rhesus monkey CD45 and can bind to various isoforms of human CD45.

[0326] The amino acid sequences of various binding regions of anti-CD45 AbB are described in Table 27. For example, anti-CD45 antibodies based on AbB containing the CDRs described in Table 27 are included in the present invention. are included in the present invention.

[0327] In one embodiment, the present invention provides an anti-CD45 antibody, or an antigen-binding fragment thereof, comprising an antigen-binding region corresponding to the antigen-binding region of AbB, such as a CDR and / or variable region. The amino acid sequence of the heavy chain variable region (VH) of AbB is set forth in SEQ ID NO: 81 (see Table 27). The amino acid sequences of the VH CDR domain of AbB are set forth in SEQ ID NO: 82 (VH CDR1); SEQ ID NO: 83 (VH CDR2) and SEQ ID NO: 84 (VH CDR3). The amino acid sequence of the light chain variable region (VL) of AbB is set forth in SEQ ID NO: 85 (see Table 27). The amino acid sequences of the VL CDR domain of AbB are set forth in SEQ ID NO: 86 (VL CDR1); SEQ ID NO: 87 (VL CDR2) and SEQ ID NO: 88 (VL CDR3).

[0328] Accordingly, in some embodiments, the present application provides a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 82, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 83, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 84; and / or a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 86, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 87; and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 88, comprising an anti-CD45 antibody, or an antigen-binding portion thereof. In certain embodiments, the anti-CD45 antibody comprises the CDRs described in the present application (SEQ ID Nos: 82 to 84 and 86 to 88), wherein the CDRs comprise conservative 1 amino acid substitutions (or 2, 3, 4, or 5 amino acid substitutions) while retaining the CD45 specificity of the antibody (i.e., specificity similar to AbB).

[0329] ​ In some embodiments, the present application provides an anti-CD45 antibody, or an antigen-binding portion thereof, comprising a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 81, and / or a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 85. In certain embodiments the antibody may comprise a modified heavy chain (HC) variable region comprising an HC variable domain comprising SEQ ID NO: 81, or a variant of SEQ ID NO: 81, wherein said variant differs from SEQ ID NO: 81 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids that differs from SEQ ID NO: 81; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids that differs from SEQ ID ID NO: 81, and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 81, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified heavy chain variable region retains the CD45 specificity of the antibody (i.e., a specificity similar to AbB) or has enhanced biological activity compared to the biological activity of another AbB heavy chain variable region. In certain embodiments, the antibody comprises a modified light chain (LC) variable region comprising an LC variable domain comprising SEQ ID NO: 85, or a variant of SEQ ID NO: 85, wherein said variant differs from SEQ ID NO: 85 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acid substitutions, additions or deletions that differ from SEQ ID NO: 85; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids that differs from SEQ ID NO: 85; and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 85, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified light chain variable region retains the CD45 specificity of the antibody (i.e., a specificity similar to AbB) or has enhanced biological activity compared to the biological activity of another AbB light chain variable region wherein (i) is different from SEQ ID NO: 85; (iii) is different from SEQ ID NO: 85 in substitutions, additions or deletions of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids, and / or (iv) comprises an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 85, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein the modified light chain variable region retains the CD45 specificity of the antibody (i.e., the specificity similar to AbB), or has enhanced biological activity as compared to the biological activity of another AbB light chain variable region.

[0330] Antibodies comprising the CDR and / or variable region sequences of AbB may be in the form of full-length antibodies, bispecific antibodies, dual variable domain antibodies, multi-chain or single-chain antibodies, and / or binding fragments that specifically bind to human CD45, for example, but not limited to, Fab, Fab', (Fab')2, Fv, scFv (single-chain Fv), diabody (including constructs of surrogate light chains) , single domain antibodies, camelized antibodies, and the like. They may also be of any isotype (e.g., IgA (e.g., IgA1 or IgA2), IgD, IgE, IgG (e.g., , IgG1, IgG2, IgG3 or IgG4), or IgM, etc.), or may be derived therefrom. In some embodiments, the anti-CD45 antibody is IgG (e.g., IgG1, IgG2, IgG3 or IgG4).

[0331] In some embodiments, an antibody comprising the CDR and / or variable region sequences of AbB may further comprise a heavy chain constant region and / or a light chain constant region. In some embodiments, the constant region is a human IgG1 constant region, a human IgG2 constant region, a human IgG3 constant region, or a human IgG4 constant region. In some embodiments, the heavy chain constant region may be a modified constant region. Exemplary constant region substitutions and / or modifications include substitutions at one or more of the following positions: 234, 235 , 265, and 435 (EU index according to Kabat). In some embodiments, an antibody comprising the CDR and / or variable region sequences of AbB may further comprise an IgG1 heavy chain constant region comprising one or more of the following substitutions: L234A, L235A, D265C, and H435A (EU index according to Kabat). In some embodiments, an antibody comprising the CDR and / or variable region sequences of AbB may further comprise a heavy chain constant region as set forth in SEQ ID NO: 102, SEQ ID NO: 103, SEQ ID NO: 104, SEQ ID NO: 105, or SEQ ID NO: 106. In some embodiments, the antibody comprises a light chain constant region as set forth in SEQ ID NO: 101.

[0332] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 89. In certain embodiments, the antibody ​may include a modified heavy chain (HC) region comprising an HC domain comprising SEQ ID NO: 89, or a variant of SEQ ID NO: 89, wherein said variant differs from SEQ ID NO: 89 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids; and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 89, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified heavy chain region retains the CD45 specificity of said antibody (i.e., specificity similar to AbB) or has enhanced biological activity compared to the biological activity of another AbB heavy chain region. differs from SEQ ID NO: 89 in (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids; and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 89, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution. In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 90. In certain embodiments, the antibody may include a modified light chain (LC) region comprising an LC domain comprising SEQ ID NO: 90, or a variant of SEQ ID NO: 90, wherein said variant differs from SEQ ID NO: 90 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or

[0333] In certain embodiments, the anti-CD45 antibody, or antigen-binding portion thereof, comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 90. In certain embodiments, the antibody may include a modified light chain (LC) region comprising an LC domain comprising SEQ ID NO: 90, or a variant of SEQ ID NO: 90, wherein said variant differs from SEQ ID NO: 90 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or in a deletion, different from SEQ ID NO: 90; (iii) in a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids, different from SEQ ID NO: 90, and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 90, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein the modified light chain region retains the CD45 specificity of the antibody (i.e., the specificity similar to AbB) or has enhanced biological activity compared to the biological activity of another AbB light chain region. In some embodiments, an antibody comprising the CDR region and / or variable region of AbB may be incorporated into an antibody-drug conjugate as described in this application. Further, an antibody comprising the CDR region and / or variable region of AbB may be used, for example, for the reduction of CD45+ cells in a subject, in the methods described in this application.

[0334] In some embodiments, an antibody comprising the CDR region and / or variable region of AbB may be incorporated into an antibody-drug conjugate as described in this application. Further, an antibody comprising the CDR region and / or variable region of AbB may be used, for example, for the reduction of CD45+ cells in a subject, in the methods described in this application. In some embodiments, an antibody comprising the CDR region and / or variable region of AbB may be incorporated into an antibody-drug conjugate as described in this application. Further, an antibody comprising the CDR region and / or variable region of AbB may be used, for example, for the reduction of CD45+ cells in a subject,

[0335] AbC Antibody C (AbC) can cross-react with human CD45, cynomolgus monkey CD45 and rhesus monkey CD45 and can bind to various isoforms of human CD45.

[0336] The amino acid sequences of various binding regions of anti-CD45 AbC are set forth in Table 27. For example, anti-CD45 antibodies based on AbC comprising the CDRs set forth in Table 27 are included in the present invention. Included in the invention are anti-CD45 antibodies based on AbC that include the CDRs set forth in Table 27.

[0337] In one embodiment, the present invention provides an anti-CD45 antibody, or an antigen-binding fragment thereof, comprising an antigen-binding region corresponding to the antigen-binding region of AbC, such as a CDR and / or variable region. The amino acid sequence of the heavy chain variable region (VH) of AbC is set forth in SEQ ID NO: 91 (see Table 27). The amino acid sequences of the VH CDR domain of AbC are set forth in SEQ ID NO: 92 (VH CDR1); SEQ ID NO: 93 (VH CDR2) and SEQ ID NO: 94 (VH CDR3). The amino acid sequence of the light chain variable region (VL) of AbC is set forth in SEQ ID NO: 95 (see Table 27). The amino acid sequences of the VL CDR domain of AbC are set forth in SEQ ID NO: 96 (VL CDR1); SEQ ID NO: 97 (VL CDR2) and SEQ ID NO: 98 (VL CDR3).

[0338] Accordingly, in some embodiments, the present application provides a heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 92, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 93, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 94; and / or a light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 96, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 97; and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 98, comprising an anti-CD45 antibody, or an antigen-binding portion thereof. In certain embodiments, the anti-CD45 antibody comprises the CDRs described in the present application (SEQ ID Nos: 92 to 94 and 96 to 98), wherein the CDRs comprise conservative 1 amino acid substitutions (or 2, 3, 4, or 5 amino acid substitutions) while retaining the CD45 specificity of the antibody (i.e., a specificity similar to AbC).

[0339] ​ In some embodiments, the present application provides an anti-CD45 antibody, or an antigen-binding portion thereof, comprising a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 91, and / or a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 95. In certain embodiments the antibody may comprise a modified heavy chain (HC) variable region comprising an HC variable domain comprising SEQ ID NO: 91, or a variant of SEQ ID NO: 91, wherein said variant differs from SEQ ID NO: 91 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids; and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 91, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified heavy chain variable region retains the CD 45 specificity of the antibody (i.e., a specificity similar to AbC) or has enhanced biological activity compared to the biological activity of another AbC heavy chain variable region. In certain embodiments, the antibody comprises a modified light chain (LC) variable region comprising an LC variable domain comprising SEQ ID NO: 95, or a variant of SEQ ID NO: 95, wherein said variant differs from SEQ ID NO: 95 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acid; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids; and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 95, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified light chain variable region retains the CD 45 specificity of the antibody (i.e., a specificity similar to AbC) or has enhanced biological activity compared to the biological activity of another AbC light chain variable region. In certain embodiments, the antibody comprises a modified light chain (LC) variable region comprising an LC variable domain comprising SEQ ID NO: 95, or a variant of SEQ ID NO: 95, wherein said variant differs from SEQ ID NO: 95 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids; and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 95, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified light chain variable region retains the CD 45 specificity of the antibody (i.e., a specificity similar to AbC) or has enhanced biological activity compared to the biological activity of another AbC light chain variable region. In certain embodiments, the antibody comprises a modified light chain (LC) variable region comprising an LC variable domain comprising SEQ ID NO: 95, or a variant of SEQ ID NO: 95, wherein said variant differs from SEQ ID NO: 95 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids; and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 95, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified light chain variable region retains the CD 45 specificity of the antibody (i.e., a specificity similar to AbC) or has enhanced biological activity compared to the biological activity of another AbC light chain variable region. In certain embodiments, the antibody comprises a modified light chain (LC) variable region comprising an LC variable domain comprising SEQ ID NO: 95, or a variant of SEQ ID NO: 95, wherein said variant differs from SEQ ID NO: 95 in (i) a substitution, addition or deletion of 1, 2, 3, 4 or 5 amino acids; (ii) a substitution, addition or deletion of at most 5, 4, 3, 2 or 1 amino acids; (iii) a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids; and / or (iv) an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 95, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid substitution; and wherein said modified light chain variable region retains the CD wherein it differs from SEQ ID NO: 95; (iii) differs from SEQ ID NO: 95 in a substitution, addition or deletion of 1-5, 1-3, 1-2, 2-5 or 3-5 amino acids, and / or (iv) comprises an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 95, wherein in any of (i)-(iv), the amino acid substitution may be a conservative amino acid substitution or a non-conservative amino acid ...

Claims

**Claim 1** An isolated anti-CD45 antibody or antigen-binding portion thereof, comprising: A heavy chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 42, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 43, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 44; and A light chain variable region comprising a CDR1 domain comprising the amino acid sequence set forth in SEQ ID NO: 46, a CDR2 domain comprising the amino acid sequence set forth in SEQ ID NO: 47, and a CDR3 domain comprising the amino acid sequence set forth in SEQ ID NO: 48, wherein the isolated anti-CD45 antibody is IgG- **Claim 2** The isolated anti-CD45 antibody or antigen-binding portion thereof according to Claim 1, wherein the heavy chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 41, and wherein the light chain variable region comprises the amino acid sequence set forth in SEQ ID NO:

45. **Claim 3** The isolated anti-CD45 antibody or antigen-binding portion thereof according to Claim 1, wherein the antibody or antigen-binding portion thereof comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 49 and a light chain comprising the amino acid sequence set forth in SEQ ID NO:

50. **Claim 4** The isolated anti-CD45 antibody or antigen-binding portion thereof according to Claim 1, wherein the antibody or antigen-binding portion thereof comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 106 and a light chain comprising the amino acid sequence set forth in SEQ ID NO:

101. **Claim 5** An antibody-drug conjugate (ADC) comprising the isolated anti-CD45 antibody or antigen-binding portion thereof according to Claim 1 conjugated to a cytotoxin via a linker. **Claim 6** The ADC according to Claim 5, wherein the heavy chain variable region comprises the amino acid sequence set forth in SEQ ID NO: 41, and wherein the light chain variable region comprises the amino acid sequence set forth in SEQ ID NO:

45. **Claim 7** The ADC according to Claim 5, Here, the antibody or its antigen-binding portion comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 49, and a light chain comprising the amino acid sequence set forth in SEQ ID NO:

50.

8. The ADC according to claim 5, wherein the cytotoxin is an indolinobenzodiazepine or an indolinobenzodiazepine pseudodimer.

9. The ADC according to claim 5, wherein the cytotoxin has a structure represented by: 【Chemical 1】 、 Here, the wavy line indicates the position of attachment of the ADC to the linker.

10. The ADC according to claim 5, wherein the anti-CD45 antibody or its antigen-binding portion conjugates to the cytotoxin via a cysteine residue at position D265 (numbering according to the EU index).

11. An antibody-drug conjugate (ADC) comprising an anti-CD45 antibody or its antigen-binding portion conjugated to a cytotoxin via a linker, wherein the anti-CD45 antibody or its antigen-binding portion comprises a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 41, and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 45, wherein the antibody is IgG1, and wherein the antibody conjugates to the linker via amino acid D265C (EU index).

12. The ADC according to claim 11, wherein the cytotoxin is an indolinobenzodiazepine or an indolinobenzodiazepine pseudodimer.

13. The ADC according to claim 11, wherein the cytotoxin has a structure represented by: 【Chemical Formula 2】 、 Here, the wavy line indicates the position of attachment of the ADC to the linker.

14. An antibody-drug conjugate (ADC) comprising an anti-CD45 antibody or its antigen-binding portion conjugated to a cytotoxin via a linker, wherein the anti-CD45 antibody or its antigen-binding portion comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 49, and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 50, wherein the antibody is IgG1, and Here, the antibody conjugates to the linker via amino acid D265C (EU index). **Claim 15** The ADC according to claim 14, wherein the cytotoxin is an indolinobenzodiazepine or an indolinobenzodiazepine pseudodimer. **Claim 16** The ADC according to claim 14, wherein the cytotoxin has a structure represented by: 【Chemical Formula 3】 、 Here, the wavy line indicates the position of the attachment of the ADC to the linker. **Claim 17** A pharmaceutical composition comprising an antibody or an antigen-binding portion thereof according to any one of claims 1 to 4, or an ADC according to any one of claims 5 to 16, and a pharmaceutically acceptable carrier. **Claim 18** A pharmaceutical composition for reducing the population of CD45+ cells in a human patient, wherein the human patient is in need thereof, wherein the pharmaceutical composition comprises an antibody or an antigen-binding portion thereof according to any one of claims 1 to 4, or an ADC according to any one of claims 5 to 16. **Claim 19** The pharmaceutical composition according to claim 18, wherein (a) the CD45+ cells are CD3+, CD19+, CD33+, CD34+, or CD45+ / B2M+; (b) the CD45+ cells are hematopoietic stem cells (HSC), T cells, B cells, and / or myeloid cells; and / or, (c) the CD45+ cells are reduced from the bone marrow of the patient and / or the peripheral blood of the patient. **Claim 20** The pharmaceutical composition according to claim 18, wherein the patient has: (a) a blood disorder; (b) a metabolic disorder; (c) cancer; (d) an autoimmune disorder; or, (e) a severe combined immunodeficiency disease (SCID). **Claim 21** The pharmaceutical composition according to claim 20, wherein the cancer is a blood cancer. **Claim 22** The pharmaceutical composition according to claim 21, wherein the blood cancer is acute myeloid leukemia, acute lymphoblastic leukemia, chronic myeloid leukemia, chronic lymphocytic leukemia, or multiple myeloma. **Claim 23** The pharmaceutical composition according to claim 20, wherein: (i) the autoimmune disorder is multiple sclerosis, type 1 diabetes, or scleroderma; or, (ii) The autoimmune disorder is selected from the group consisting of multiple sclerosis, human systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disease, psoriasis treatment, type 1 diabetes, acute disseminated encephalomyelitis, Addison's disease, alopecia universalis, ankylosing spondylitis, antiphospholipid antibody syndrome, aplastic anemia, autoimmune hemolytic anemia, autoimmune hepatitis, autoimmune inner ear disease, autoimmune lymphoproliferative syndrome, autoimmune oophoritis, Barlow's disease, Behçet's disease, bullous pemphigoid, cardiomyopathy, Chagas disease, chronic fatigue immune deficiency syndrome, chronic inflammatory demyelinating polyneuropathy, Crohn's disease, cicatricial pemphigoid, coeliac sprue-dermatitis herpetiformis, cold agglutinin disease, CREST syndrome, Degos disease, discoid lupus erythematosus, autonomic neuropathy, endometriosis, essential mixed cryoglobulinemia, fibromyalgia-fibromyositis, Goodpasture syndrome, Graves' disease, Guillain-Barré syndrome (GBS), Hashimoto's thyroiditis, hidradenitis suppurativa, idiopathic and / or acute thrombocytopenic purpura, idiopathic pulmonary fibrosis, IgA neuropathy, interstitial cystitis, juvenile arthritis, Kawasaki disease, lichen planus, Lyme disease, Menière's disease, mixed connective tissue disease, myasthenia gravis, neuromyotonia, opsoclonus-myoclonus syndrome, optic neuritis, Ord's thyroiditis, pemphigus vulgaris, pernicious anemia, polychondritis, polymyositis and dermatomyositis, primary biliary cirrhosis, polyarteritis nodosa, polyendocrine syndrome, rheumatoid polymyalgia, primary agammaglobulinemia, Raynaud's phenomenon, Reiter's syndrome, rheumatic fever, sarcoidosis, scleroderma, Sjögren's syndrome, stiff person syndrome, Takayasu arteritis, temporal arteritis, ulcerative colitis, uveitis, vasculitis, vitiligo, vulvodynia, and Wegener's granulomatosis.

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