US-20260125479-A1 - ANTI-KLRG1 ANTIBODIES

Abstract

The invention relates to antibodies, or antigen-binding fragments thereof, that specifically binds to killer cell lectin-like receptor G1 (KLRG1). Such antibodies, or antigen-binding fragments thereof, are useful for various therapeutic or diagnostic purposes including treatment of cancers and to increase the effectiveness of vaccines.

Inventors

• Stefano V. Gulla
• Kenneth Evan Thompson

Assignees

• THE BRIGHAM AND WOMEN'S HOSPITAL, INC.

Dates

Publication Date

20260507

Application Date

20250610

Claims (8)

1. 1 .- 31 . (canceled)
2. 32 . An isolated nucleic acid sequence comprising a nucleic acid sequence that encodes a heavy chain variable (VH) domain and/or a nucleic acid sequence that encodes a light chain variable (VL) domain of an antibody or antigen binding fragment thereof that binds to the extracellular domain of human killer cell lectin-like receptor subfamily G member 1 (KLRG1), wherein: (a) the VH domain comprises complementarity-determining regions (CDRs) of CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequences of SEQ ID NOs: 13, 14, and 15, respectively; and (b) the VL domain comprises CDR-L2 and CDR-L3 comprising the amino acid sequences of SEQ ID NO: 17 and 18, respectively and a CDR-L1 comprising the amino acid sequence of SEQ ID NO: 16 or the amino acid sequence of SEQ ID NO: 16 wherein NG is substituted with NA, QG, or KG.
3. 33 . The isolated nucleic acid sequence of claim 32 , wherein CDR-L1 (SEQ ID NO: 16) has NG substituted with NA.
4. 34 . The isolated nucleic acid sequence of claim 32 wherein: (i) the VH domain comprises the amino acid sequence of SEQ ID NO: 3 and the VL domain comprises the amino acid sequence of SEQ ID NO: 4 or the amino acid sequence of SEQ ID NO: 4 wherein NG is substituted with NA in the CDR-L1; or (ii) the VH domain comprises the amino acid sequence of SEQ ID NO: 27 and the VL domain comprises the amino acid sequence of SEQ ID NO: 28 or the amino acid sequence of SEQ ID NO: 28 wherein NG is substituted with NA.
5. 35 . An expression vector comprising at least one isolated nucleic acid sequence of claim 32 .
6. 36 . A host cell comprising one or more expression vectors of claim 35 .
7. 37 . The host cell of claim 36 , wherein the host cell is chosen from: an E. coli bacterium, a Chinese hamster ovary cell, a HeLa cell, and a NS0 cell.
8. 38 . A method of making an antibody or antigen binding fragment thereof comprising culturing the host cell of claim 36 under appropriate conditions and isolating and/or purifying the antibody or antigen binding fragment thereof so produced.

Description

TECHNICAL FIELD The technical field relates to inhibition of the lymphocyte co-inhibitory receptor Killer Cell Lectin-Like Receptor Subfamily G Member 1 (KLRG1). BACKGROUND Lymphocyte co-inhibitory receptors modulate the action of the adaptive immune system, for example T cells and NK cells, in response to activating signals such as antigenic peptides in the context of the major histocompatibility complex (MIHC) binding to the T cell receptor (TCR). Co-inhibitory receptors include PD-1, LAG-3, TIM-3, and CTLA4. The action of co-inhibitory receptors is generally carried out by binding of a ligand to the extracellular domain of the co-inhibitory receptor followed by recruitment of intracellular phosphatases by an immunoreceptor tyrosine-based inhibition motif (ITIM) located in the intracellular domain of the co-inhibitory receptor. The action of co-inhibitory receptors is generally to dampen the immune response of TCR engagement. In recent years it has been shown that agents that block the activity of co-inhibitory receptors can be used to as efficacious treatments for cancer and infectious diseases. Killer cell lectin-like receptor G1 (KLRG1) is a type 11 transmembrane protein acting as co-inhibitory receptor by modulating the activity of T and NK cells. Its extracellular portion contains a C-type lectin domain whose known ligands are cadherins and its intracellular portion contains an immunoreceptor tyrosine-based inhibitory motif (ITIM) domain responsible for co-inhibition of T cell receptor (TCR) mediated signaling. KLRG1 ligands can be E-cadherin, N-cadherin, R-cadherin, or a combination thereof. The receptor killer cell lectin-like receptor G1 (KLRG1) is expressed on T and NK cells which binds to ligands on epithelial and mesenchymal cells. The ligand for KLRG1 have been described to be E-cadherin, N-cadherin and R-cadherin. In humans, KLRG1 expression is confined to cells of the immune systems and specifically to CD8 positive T cells, NK cells and to a lesser extent to CD4 positive T cells. KLRG1 expression has been associated with the late differentiated phenotype. As antigen specific T cells differentiate they acquire increased expression of cytotoxic molecules and therefore have increased cytotoxic potential. The biological function of KLRG1 is to inhibit cytotoxicity and proliferation of these T cells. In cancer and infectious disease, it has been shown beneficial to restore T cell activity. In general, a need exists to provide safe and effective therapeutic methods for cancer or infectious diseases. Modulation of the cytotoxic (or CD8+) T and NK cell activation involved in these disorders can be accomplished by manipulation of the KLRG1 pathway. SUMMARY The present disclosure provides characterization of novel antibodies, or antigen binding fragments thereof, that bind the extracellular domain (ECD) of KLRG1 and inhibit its interaction with ligands E-cadherin, N-cadherin and R-cadherin. The antibodies here described have been derived by mouse hybridoma technology and can be humanized by grafting their complementary determining regions (CDRs) into a human framework. The disclosure also provides antibodies or binding fragments that modulate (e.g., activate) CD8+ cytotoxic T and NK cells and do so by modulating (e.g., neutralizing) the interaction between KLRG1 and its ligands. The antibodies here described can be used as effective therapeutic agents for treatment of cancer either as monotherapy, or in combination with other immunotherapy agents (such as anti-PD-1 antibodies, anti-PD-L1 antibodies, or anti-CTLA4 antibodies), or in combination with chemotherapy agents, or cancer vaccines. The antibodies here described can be used as effective treatments for infectious diseases or to enhance the effectiveness of vaccines against infectious diseases. Nonlimiting illustrative embodiments of the antibodies are referred to as ABC_HG1N01, ABC_HG1N02, ABC_HG1N07, ABC_G1N01, ABC_G1N02, ABC_G1N03, ABC_G1N04, ABC_G1N05, ABC_G1N06, ABC_G1N07, or ABC_G1N08. Other embodiments comprise a VH and/or VL domain of the Fv fragment of ABC_HG1N01, ABC_HG1N02, ABC_HG1N07, ABC_G1N01, ABC_G1N02, ABC_G1N03, ABC_G1N04, ABC_G1N05, ABC_G1N06, ABC_G1N07, or ABC_G1N08. Further embodiments comprise one or more CDRs of any of these VH and VL domains. Other embodiments comprise an H3 fragment of the VH domain of ABC_HG1N01, ABC_HG1N02, ABC_HG1N07, ABC_G1N01, ABC_G1N02, ABC_G1N03, ABC_G1N04, ABC_G1N05, ABC_G1N06, ABC_G1N07, and ABC_G1N08. The disclosure also provides compositions comprising KLRG1 antibodies, and their use in methods of modulating immune response, including methods of treating humans or animals. In particular embodiments, anti-KLRG1 antibodies are used to treat or prevent cancer by virtue of activating CD8+ cytotoxic T and NK cells. Disorders susceptible to treatment with compositions of the invention include but are not limited cancer and infectious diseases. Additionally, anti-KLRG1 antibodies may be used diagnostica