Antibodies to lilrb1 and lilrb2 and compositions thereof

Abstract

The present disclosure provides antibodies that bind to LILB1 and LILRB2, and methods of using them to enhance immunity in a patient in need thereof and to treat cancer.

Description

ANTIBODIES TO LILRB1 AND LILRB2 AND COMPOSITIONS THEREOFBACKGROUND OF THE INVENTION

[0001] Leukocyte immunoglobulin-like receptors Bl (LILRB1) and B2 (LILRB2) are two of the five members of the leukocyte immunoglobulin-like receptor B family. LILRB receptors are expressed on various immune cells, including monocytes, macrophages, and dendritic cells (LILRB 1 and LILRB2), and NK cells and B and T lymphocytes (LILRB 1). LILRB expression has also been seen in multiple cancer cell types. Binding of LILRB 1 and LILRB2 to MHC class I molecules on antigen-presenting cells results in inhibition of the immune response, decreasing anti-tumor immunity and blocking immune pathways to cancer treatment.

[0002] In view of the role of LILRB 1 and LILRB2 in the immune response, and the repercussions thereof for cancer treatment, there is a need for new and improved immune- enhancing and anti-cancer therapies that target LILRB 1 and LILRB2.SUMMARY OF THE INVENTION

[0003] The present disclosure provides an antibody that specifically binds to LILRB 1 and LILRB2 (“anti-LILRBl / 2 antibody”) or an antigen-binding portion thereof. Also provided are pharmaceutical compositions comprising one or more of these antibodies, and use of the antibodies and pharmaceutical compositions for enhancing the immune response in a patient, e.g., for treatment of cancer. Compared to currently available treatments for cancer, including antibody treatments, it is contemplated that the antibodies and compositions described herein may provide a superior clinical response either alone or in combination with another cancer therapeutic.

[0004] In some embodiments, the present disclosure provides an anti -LILRB 1 / 2 antibody or an antigen-binding portion thereof, wherein the antibody binds to the same epitope of human LILRB 1 and / or human LILRB2 as an antibody comprising: a) a heavy chain (HC) comprising the amino acid sequences of SEQ ID NOs: 3 and 61 and a light chain (LC) comprising the amino acid sequences of SEQ ID NOs: 4 and 62; b) an HC comprising the amino acid sequences of SEQ ID NOs: 13 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 14 and 62; c) an HC comprising the amino acid sequences of SEQ ID NOs: 23 and 61 and anLC comprising the amino acid sequences of SEQ ID NOs: 24 and 62; d) an HC comprising the amino acid sequences of SEQ ID NOs: 33 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 34 and 62; or e) an HC comprising the amino acid sequences of SEQ ID NOs: 43 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 44 and 62.

[0005] In some embodiments, the present disclosure provides an anti -LILRB 1 / 2 antibody or an antigen-binding portion thereof, wherein a) the heavy chain of said anti -LILRB 1 / 2 antibody comprises: i) heavy chain complementarity determining regions (H-CDR)-l-3 comprising the amino acid sequences of SEQ ID NOs: 5-7, respectively; ii) a heavy chain variable domain (VH) comprising an amino acid sequence at least 90% identical to the amino acid sequence of SEQ ID NO: 3; iii) a VH comprising the amino acid sequence of SEQ ID NO: 3; or iv) an HC comprising the amino acid sequences of SEQ ID NOs: 3 and 61; and b) the light chain of said anti -LILRB 1 / 2 antibody comprises: i) light chain complementarity determining regions (L-CDR)-l-3 comprising the amino acid sequences of SEQ ID NOs: 8-10, respectively; ii) a light chain variable domain (VL) comprising an amino acid sequence at least 90% identical to the amino acid sequence of SEQ ID NO: 4; iii) a VL comprising the amino acid sequence of SEQ ID NO: 4; or iv) an LC comprising the amino acid sequences of SEQ ID NOs: 4 and 62.

[0006] In some embodiments, the present disclosure provides an anti -LILRB 1 / 2 antibody or an antigen-binding portion thereof, wherein a) the heavy chain of said anti -LILRB 1 / 2 antibody comprises: i) H-CDR1-3 comprising the amino acid sequences of SEQ ID NOs: 15-17, respectively; ii) a VH comprising an amino acid sequence at least 90% identical to the amino acid sequence of SEQ ID NO: 13; iii) a VH comprising the amino acid sequence of SEQ ID NO: 13; or iv) an HC comprising the amino acid sequences of SEQ ID NOs: 13 and 61; and b) the light chain of said anti -LILRB 1 / 2 antibody comprises: i) L-CDR1-3 comprising the amino acid sequences of SEQ ID NOs: 18-20, respectively; ii) a VL comprising an amino acid sequence at least 90% identical to the amino acid sequence of SEQ ID NO: 14;iii) a VL comprising the amino acid sequence of SEQ ID NO: 14; or iv) an LC comprising the amino acid sequences of SEQ ID NOs: 14 and 62.

[0007] In some embodiments, the present disclosure provides an anti -LILRB 1 / 2 antibody or an antigen-binding portion thereof, wherein a) the heavy chain of said anti -LILRB 1 / 2 antibody comprises: i) H-CDR1-3 comprising the amino acid sequences of SEQ ID NOs: 25-27, respectively; ii) a VH comprising an amino acid sequence at least 90% identical to the amino acid sequence of SEQ ID NO: 23; iii) a VH comprising the amino acid sequence of SEQ ID NO: 23; or iv) HC comprising the amino acid sequences of SEQ ID NOs: 23 and 61; and b) the light chain of said anti -LILRB 1 / 2 antibody comprises: i) LCDR1-3 comprising the amino acid sequences of SEQ ID NOs: 28-30, respectively; ii) a VL comprising an amino acid sequence at least 90% identical to the amino acid sequence of SEQ ID NO: 24; iii) a VL comprising the amino acid sequence of SEQ ID NO: 24; or iv) an LC comprising the amino acid sequences of SEQ ID NOs: 24 and 62.

[0008] In some embodiments, the present disclosure provides an anti -LILRB 1 / 2 antibody or an antigen-binding portion thereof, wherein a) the heavy chain of said anti -LILRB 1 / 2 antibody comprises: i) H-CDR1-3 comprising the amino acid sequences of SEQ ID NOs: 35-37, respectively; ii) a VH comprising an amino acid sequence at least 90% identical to the amino acid sequence of SEQ ID NO: 33; iii) a VH comprising the amino acid sequence of SEQ ID NO: 33; or iv) an HC comprising the amino acid sequences of SEQ ID NOs: 33 and 61; and b) the light chain of said anti -LILRB 1 / 2 antibody comprises: i) L-CDR1-3 comprising the amino acid sequences of SEQ ID NOs: 38-40, respectively; ii) a VL comprising an amino acid sequence at least 90% identical to the amino acid sequence of SEQ ID NO: 34; iii) a VL comprising the amino acid sequence of SEQ ID NO: 34; or iv) an LC comprising the amino acid sequences of SEQ ID NOs: 34 and 62.

[0009] In some embodiments, the present disclosure provides an anti -LILRB 1 / 2 antibody or an antigen-binding portion thereof, whereina) the heavy chain of said anti -LILRB 1 / 2 antibody comprises: i) H-CDR1-3 comprising the amino acid sequences of SEQ ID NOs: 45-47, respectively; ii) a VH comprising an amino acid sequence at least 90% identical to the amino acid sequence of SEQ ID NO: 43; iii) a VH comprising the amino acid sequence of SEQ ID NO: 43; or iv) an HC comprising the amino acid sequences of SEQ ID NOs: 43 and 61; and b) the light chain of said anti -LILRB 1 / 2 antibody comprises: i) L-CDR1-3 comprising the amino acid sequences of SEQ ID NOs: 48-50, respectively; ii) a VL comprising an amino acid sequence at least 90% identical to the amino acid sequence of SEQ ID NO: 44; iii) a VL comprising the amino acid sequence of SEQ ID NO: 44; or iv) an LC comprising the amino acid sequences of SEQ ID NOs: 44 and 62.

[0010] In some embodiments, the present disclosure provides an anti -LILRB 1 / 2 antibody or an antigen-binding portion thereof, wherein said antibody comprises the H-CDR1-3 and L- CDR1-3 amino acid sequences of: a) SEQ ID NOs: 5-10, respectively; b) SEQ ID NOs: 15-20, respectively; c) SEQ ID NOs: 25-30, respectively; d) SEQ ID NOs: 35-40, respectively; or e) SEQ ID NOs: 45-50, respectively.

[0011] In some embodiments, the anti -LILRB 1 / 2 antibody or antigen-binding portion comprises a heavy chain variable domain amino acid sequence and a light chain variable domain amino acid sequence that are at least 90% identical to the amino acid sequences of: a) SEQ ID NOs: 3 and 4, respectively; b) SEQ ID NOs: 13 and 14, respectively; c) SEQ ID NOs: 23 and 24, respectively; d) SEQ ID NOs: 33 and 34, respectively; or e) SEQ ID NOs: 43 and 44, respectively.

[0012] In some embodiments, the anti -LILRB 1 / 2 antibody or antigen-binding portion comprises a heavy chain variable domain and a light chain variable domain comprising the amino acid sequences of: a) SEQ ID NOs: 3 and 4, respectively; b) SEQ ID NOs: 13 and 14, respectively;c) SEQ ID NOs: 23 and 24, respectively; d) SEQ ID NOs: 33 and 34, respectively; or e) SEQ ID NOs: 43 and 44, respectively.

[0013] In some embodiments, the anti -LILRB 1 / 2 antibody is an IgG, e.g., an IgGi. The antibody may comprise at least one mutation in the Fc region. For example, in certain embodiments, the anti -LILRB 1 / 2 antibody is of isotype subclass IgGi and one or both of the amino acid residues at positions 234 and 235 are mutated from Leu to Ala.

[0014] In some embodiments, the anti -LILRB 1 / 2 antibody comprises: a) an HC comprising the amino acid sequences of SEQ ID NOs: 3 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 4 and 62; b) an HC comprising the amino acid sequences of SEQ ID NOs: 13 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 14 and 62; c) an HC comprising the amino acid sequences of SEQ ID NOs: 23 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 24 and 62; d) an HC comprising the amino acid sequences of SEQ ID NOs: 33 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 34 and 62; or e) an HC comprising the amino acid sequences of SEQ ID NOs: 43 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 44 and 62.

[0015] In some embodiments, the present disclosure provides an anti -LILRB 1 / 2 antibody or an antigen-binding portion thereof, wherein said antibody or antigen-binding portion binds to an epitope on human LILRB 1 comprising amino acid residues G19, P21, W46, R49, 150, P51, F60, P63, S64, and H69; or comprising amino acid residues El 1-R25 and optionally further comprising amino acid residues R36-I65 or K41-I65.

[0016] In some embodiments, the anti-LILRBl / 2 antibody or antigen-binding portion of the present disclosure has at least one property selected from: a) binds to human LILRB 1 with a KD of 0.1 nM or less as measured by surface plasmon resonance (SPR); b) binds to human LILRB2 with a KD of 10 nM or less as measured by surface plasmon resonance (SPR); c) binds to human LILRB 1 with an ECso of 0.1 nM or less as measured by ELISA; d) binds to human LILRB2 with an ECso of 0.2 nM or less as measured by ELISA; e) binds to human LILRA1 with a KD of 1 nM or less as measured by surface plasmon resonance (SPR); f) binds to human LILRA2 with a KD of 20 nM or less as measured by surfaceplasmon resonance (SPR); g) binds to human LILRA3 with a KD of 1.1 nM or less as measured by surface plasmon resonance (SPR); h) does not bind to human LILRB3, LILRB4, LILRB5, LILRA4, LILRA5, and LILRA6; i) does not bind to rhesus, marmoset, or cynomolgus LILRB 1 ; j) binds to rhesus LILRA1, LILRA2, and LILRA3, cynomolgus LILRA2 and LILRA3, and marmoset LILRA; k) binds to LILRB 1 polymorphic variants L45P, Il 19T, S132I, L45P / I119T, L45P / I119T / S132I, and A70P / L45P / I119T / S132I; l) binds to domain 1 of human LILRB 1 ; m) binds to a different epitope of human LILRB 1 than anti -LILRB 1 / 2 antibody NGM707 or anti -LILRB 1 antibody BND-22; n) binds to CD20+B cells, CD14+monocytes, CD56+NK cells, and CD8+T cells; o) blocks LILRB 1 binding to HLA-G / B2M and HLA-A2 / B2M; p) blocks LILRB2 binding to HLA-G / B2M and HLA-A2 / B2M; q) enhances cytolytic NK cell activity; r) induces secretion of TNFa and GM-CSF, and / or reduces secretion of IL-10, in a PBMC / LPS assay; s) induces secretion of TNFa, IFNy, and GM-CSF, and / or limits secretion of IL-6, in a PBMC / anti-CD3 assay; t) enhances macrophage phagocytosis of HLA-G-expressing cells; u) increases secretion of TNFa and IFNY in amixed lymphocyte reaction (MLR) assay; v) increases proliferation and activation of CD4+ T cells in an MLR assay; and w) demonstrates full LILRB 1 and LILRB2 receptor occupancy at Q3W and Q4W in a two-compartment pharmacokinetic model with linear elimination kinetics.In certain embodiments, the antibody or antigen-binding portion has all of said properties.

[0017] The present disclosure also provides a pharmaceutical composition comprising an anti -LILRB 1 / 2 antibody or antigen-binding portion as described herein. In some embodiments, the pharmaceutical composition further comprises an immunostimulatory agent, a vaccine, a chemotherapeutic agent, an anti-neoplastic agent, an anti -angiogenic agent, or a tyrosine kinase inhibitor, or any combination thereof.

[0018] The present disclosure also provides isolated nucleic acid molecule(s) comprisinga nucleotide sequence that encodes the heavy chain, or a nucleotide sequence that encodes the light chain, or both, of an anti-LILRB 1 / 2 antibody or antigen-binding portion as described herein. In some embodiments, the nucleic acid molecule(s) comprise the nucleotide sequence of any one of SEQ ID NOs: 1, 2, 11, 12, 21, 22, 31, 32, 41, and 42, or any combination thereof (e.g., SEQ ID NOs: 1 and 2, 11 and 12, 21 and 22, 31 and 32, or 41 and 42).

[0019] The present disclosure also provides vector(s) comprising isolated nucleic acid molecule(s) as described herein, wherein said vector(s) may further comprise an expression control sequence.

[0020] The present disclosure also provides a host cell comprising a nucleotide sequence that encodes the heavy chain, and a nucleotide sequence that encodes the light chain, of an anti-LILRB 1 / 2 antibody or antigen-binding portion as described herein.

[0021] Also provided is a method for producing an anti-LILRB 1 / 2 antibody or an antigen-binding portion thereof, comprising providing a host cell as described above, culturing said host cell under conditions suitable for expression of the antibody or antigenbinding portion, and isolating the resulting antibody or antigen-binding portion.

[0022] The present disclosure also provides a bi-specific binding molecule comprising the antigen-binding domain of an anti-LILRB 1 / 2 antibody as described herein and the antigen-binding domain of another, distinct antibody.

[0023] The present disclosure also provides a method of using an anti-LILRB 1 / 2 antibody or antigen-binding portion as described herein in a diagnostic process, comprising contacting a sample from a patient (e.g., a human patient) with said antibody or antigenbinding portion, and detecting and / or measuring the level of LILRB1 and / or LILRB2.

[0024] The present disclosure also provides a method for enhancing immune activity in a patient (e.g., a human patient) in need thereof, comprising administering to said patient a therapeutically effective amount of an anti-LILRB 1 / 2 antibody or antigen-binding portion, pharmaceutical composition, or bi-specific binding molecule as described herein.

[0025] The present disclosure also provides a method for treating cancer in a patient (e.g., a human patient) in need thereof, comprising administering to said patient a therapeutically effective amount of an anti-LILRB 1 / 2 antibody or antigen-binding portion, pharmaceutical composition, or bi-specific binding molecule as described herein. In some embodiments, the cancer is in or originates from a tissue selected from the group consisting of skin, lung, intestine, colon, ovary, brain, prostate, kidney, soft tissues, the hematopoietic system, head and neck, liver, bone, bladder, breast, stomach, uterus, cervix, and pancreas. In some embodiments, the cancer is selected from ovarian cancer, cutaneous squamous cellcarcinoma, esophageal cancer, breast, head and neck squamous cell carcinoma, non-small cell lung cancer, sarcoma, biliary tract cancer, and gallbladder cancer.

[0026] The present disclosure also provides a method for treating an immune disorder in a patient (e.g., a human patient) in need thereof, comprising administering to said patient a therapeutically effective amount of an anti -LILRB 1 / 2 antibody or antigen-binding portion, pharmaceutical composition, or bi-specific binding molecule as described herein.

[0027] In some embodiments, the above therapeutic methods may further comprise administering to the patient an immunostimulatory agent, a vaccine, a chemotherapeutic agent, an anti -neoplastic agent, an anti -angiogenic agent, a tyrosine kinase inhibitor, or radiation therapy.

[0028] The present disclosure also provides the use of an anti -LILRB 1 / 2 antibody or antigen-binding portion, pharmaceutical composition, or bi-specific binding molecule as described herein for the manufacture of a medicament for: a) enhancing immune activity in a patient; b) treating cancer in a patient; or c) treating an immune disorder in a patient, according to a method described herein. In particular embodiments, the patient is a human patient in need thereof.

[0029] The present disclosure also provides an anti -LILRB 1 / 2 antibody or antigenbinding portion, pharmaceutical composition, or bi-specific binding molecule as described herein for use in: a) enhancing immune activity in a patient; b) treating cancer in a patient; or c) treating an immune disorder in a patient, according to a method described herein. In particular embodiments, the patient is a human patient in need thereof.

[0001] It is understood that the present disclosure also provides an antibody, antigenbinding portion thereof, binding protein, or pharmaceutical composition described herein for use in treating a human in need thereof in a therapeutic method described herein. Also provided are uses of an antibody, antigen-binding portion thereof, binding protein, or pharmaceutical composition described herein for the manufacture of a medicament for treating a human patient in need thereof in a therapeutic method described herein.

[0030] Other features, objectives, and advantages of the invention are apparent in the detailed description that follows. It should be understood, however, that the detaileddescription, while indicating embodiments and aspects of the invention, is given by way of illustration only, not limitation. Various changes and modification within the scope of the invention will become apparent to those skilled in the art from the detailed description.BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG. 1 is a set of line graphs that show binding of anti -LILRB 1 / 2 antibodies28425.30976 and 28425.34436 to CHO-S cells transfected with LILRB1-5 or mock control. Data are shown as mean ± SD of triplicates.

[0032] FIG. 2 is a set of line graphs that show binding of anti -LILRB 1 / 2 antibodies28425.30976 and 28425.34436 to CHO-S cells transfected with LILRA1-6. Data are shown as mean ± SD of triplicates.

[0033] FIG. 3 is a set of line graphs that show binding of anti -LILRB 1 / 2 antibodies28425.30976 and 28425.34436 and reference analogue antibodies to human LILRB 1 or LILRB2 as assessed by ELISA. Data from one representative experiment are shown as mean ± SD of triplicates.

[0034] FIG. 4 is a set of line graphs that show binding of anti -LILRB 1 / 2 antibodies28425.30976 and 28425.34436 and reference analogue antibodies to human CD20+B-cells, CD14+monocytes, CD56+NK cells and CD8+isolated T cells. Data are shown for two representative donors.

[0035] FIG. 5 is a set of line graphs that show binding of anti -LILRB 1 / 2 antibodies28425.30976 and 28425.34436 and reference analogue antibodies to CHO-S cells transfected with rhesus LILRB 1, LILRA1, LILRA2, or LILRA3 or marmoset LILRB 1 or LILRA, or mock control. Data are shown as mean ± SD of triplicates.

[0036] FIG. 6 is a set of line graphs that show binding of anti -LILRB 1 / 2 antibodies28425.30976 and 28425.34436 and reference analogue antibodies to CHO-S cells transfected with cynomolgus LILRB 1, LILRA2 and LILRA3. Data are shown as mean ± SEM of duplicates.

[0037] FIG. 7 is a set of line graphs that show binding of anti -LILRB 1 / 2 antibodies28425.30976 and 28425.34436 or anti-V5 tag antibodies to CHO-S cells transfected with LILRB 1 wild-type (WT) ECD or one of six polymorphic ECD variants of human LILRB 1. Data are shown as mean ± SEM of duplicate wells. All of the LILRB 1 variants are expressed at different levels as suggested by the single well assessment of anti-V5 tag antibody staining in the lower graph.

[0038] FIG. 8A is a cartoon showing the epitope of anti -LILRB 1 / 2 antibodies 28425.30976 and 28425.34436 mapped on the structure of LILRB l :HLA-G:P2m complex (PDB 6AEE) or LILRB2 in complex with HLA-G / p2m (PDB: 2DYP). LILRB 1 and LILRB2 domain 1 and 2 (DI and D2) are colored dark gray and shown as surface representation. HLA-G and P2m are colored grey and shown as ribbon diagram. The linear epitopes are colored light grey and contact residues are colored black.Epitope of 28425.30976 and 28425.34436 mapped on LILRB 1 (left) and LILRB2 (right).

[0039] FIG. 8B is a cartoon showing the epitope of the NGM707 analogue mapped on LILRB 1 (left) and LILRB2 (right). Coloring is as described in FIG. 8A.

[0040] FIG. 8C is a cartoon showing the epitope of the BND-22 analogue mapped on the structure of LILRB 1 :HLA-G:P2m complex (PDB 6AEE). Coloring is as described in FIG.8A.

[0041] FIG. 9 is a set of line graphs that show the ligand blocking curves of different anti-LILRB antibodies to CHO-S cells. Anti-LILRBl / 2 antibodies 28425.30976 and 28425.34436 and reference analogue antibodies have been tested for the ability to block LILRB 1 binding to HLA-G / B2M (top left); LILRB2 binding to HLA-G / B2M (top right); LILRB 1 binding to HLA-A2 / B2M (bottom left); and LILRB2 binding to HLA-A2 / B2M (bottom right). Data are presented as mean ± SEM.

[0042] FIG. 10 is a set of line graphs that show NK cell cytotoxicity of the anti- LILRB 1 / 2 antibodies. Panel A shows the cytotoxicity of anti-LILRB 1 / 2 antibody 28425.30976, which enhanced tumor cell killing compared to isotype control in a dose dependent manner. Panel B compares 28425.30976 and 28425.34436 cytotoxicity to that of reference analogues. Data from one representative experiment are shown as mean ± SD of triplicates.

[0043] FIG. 11 is a bar graph that shows in vitro characterization of selected anti-LILRB monoclonal antibodies in a macrophage phagocytosis assay. Data from one representative experiment are shown as mean ± SD of triplicates.

[0044] FIG. 12A is a set of box and whisker plots that represent TNFa, GM-CSF and IL- 10 (from left to right) release following treatment with 28425.30976, 28425.34436, reference analogue or isotype control antibodies in >10 independent PBMC donors. Data are represented as mean ± SD.

[0045] FIG. 12B is a set of line graphs that show the same data as FIG. 12A represented as a direct comparison between the isotype control treatment and 28425.30976 for each independent donor and for the same cytokines of interest.

[0046] FIG. 13A is a set of box and whisker plots that represent TNFa, IFNy, GM-CSF and IL-6 (from left to right) release following treatment with 28425.30976, 28425.34436, reference analogue or isotype control antibodies in 5 independent PBMC donors. Data are represented as mean ± SD.

[0047] FIG. 13B is a set of line graphs that show the same data as FIG. 13A represented as a direct comparison between the isotype control treatment and 28425.30976 for each independent donor and for the same cytokines of interest.

[0048] FIG. 14 is a set of graphs that demonstrate the effect of anti-LILRB treatment on modulating M2 -macrophage driven CD4 MLR responses. Panel A shows the secretion of TNFa as analyzed by ELISA from assay culture supernatants on day 5 of the MLR culture. Panel B shows the secretion of IFNy by ELISA from supernatants at day 5 of the MLR culture. Panel C shows the secretion of TNFa by ELISA from assay culture supernatants 24 hrs after LPS maturation. For Panels A-C, each symbol represents an independent M2 macrophage donor treated with anti-LILRB antibodies, KEYTRUDA® or isotype control. All data represented as mean ± SD. Panel D shows normalized mean fluorescence intensity levels assessed using flow cytometry for the expression of (from left to right) Ki-67, CD25 and HLA-DR on viable CD4+T cells on day 7 of in vitro culture. Each line represents T cells from an independent T cell donor cultured in the presence of allogeneic CD14+monocyte derived M2 -polarized macrophages treated with 28425.30976 or isotype control. Data are represented as MFI levels normalized to isotype controls of the respective detection antibodies of the selected antigens.

[0049] FIG. 15 is a line graph that shows in vivo pharmacokinetic (PK) profiles (plasma concentration over time) for four doses of antibody 28425.30976 in a single dose PK study in hFcRn mice. Doses of 0.1 mg / kg, 1 mg / kg or 10 mg / kg were administered by intravenous (IV) or intraperitoneal (IP) routes and blood samples were drawn at different timepoints following the administration as marked.

[0050] FIG. 16 is a line graph that shows the PK modeling of the NGM707 analogue (200 mg Q3W) and anti-LILRBl / 2 antibody 28425.30976 at two dose levels: 200 mg Q4W and 200 mg Q3W.

[0051] FIG. 17 is a line graph that shows the percent receptor occupancy modeling of the NGM707 analogue (200 mg Q3W) and anti-LILRBl / 2 antibody 28425.30976 at two dose levels (200 mg Q4W and 200 mg Q3W).DETAILED DESCRIPTION OF THE INVENTION

[0052] The present disclosure provides new antibodies that specifically bind to LILRB1 and LILRB2 (“ anti -LILRB 1 / 2 antibodies”), or antigen-binding portions thereof, that can be used to enhance the immune response in a patient, e.g., for treatment of cancer. Also provided are related binding proteins (e.g., multispecific binding molecules, immunoconjugates, etc.) and pharmaceutical compositions comprising one or more of these antibodies or antigen-binding portions thereof or binding proteins. The antibodies and antigen-binding portions thereof, binding proteins, and compositions described herein may be used in a method for enhancing the immune response or for treating cancer in a patient; may be used for the manufacture of a medicament for enhancing the immune response or for treating cancer in a patient; or may be for use in enhancing the immune response or treating cancer in a patient. The patient may be, e.g., a human patient in need of said enhancement or treatment.

[0053] Unless otherwise stated, “LILRB 1” and “LILRB2” refer to human LILRB 1 and human LILRB2. A human LILRB 1 polypeptide sequence is available under UniProt Accession No. Q8NHL6, as shown below:MTPILTVLICLGLSLGPRTHVQAGHLPKPTLWAEPGSVITQGSPVTLRCQGGQETQEYR LYREKKTALWITRIPQELVKKGQFPIPSITWEHAGRYRCYYGSDTAGRSESSDPLELVV TGAYIKPTLSAQPSPVVNSGGNVILQCDSQVAFDGFSLCKEGEDEHPQCLNSQPHARGS SRAIFSVGPVSPSRRWWYRCYAYDSNSPYEWSLPSDLLELLVLGVSKKPSLSVQPGPIV APEETLTLQCGSDAGYNRFVLYKDGERDFLQLAGAQPQAGLSQANFTLGPVSRSYGGQY RCYGAHNLSSEWSAPSDPLDILIAGQFYDRVSLSVQPGPTVASGENVTLLCQSQGWMQT FLLTKEGAADDPWRLRSTYQSQKYQAEFPMGPVTSAHAGTYRCYGSQSSKPYLLTHPSD PLELVVSGPSGGPSSPTTGPTSTSGPEDQPLTPTGSDPQSGLGRHLGVVIGILVAVILL LLLLLLLFLILRHRRQGKHWTSTQRKADFQHPAGAVGPEPTDRGLQWRSSPAADAQEEN LYAAVKHTQPEDGVEMDTRSPHDEDPQAVTYAEVKHSRPRREMASPPSPLSGEFLDTKD RQAEEDRQMDTEAAASEAPQDVTYAQLHSLTLRREATEPPPSQEGPSPAVPSIYATLAI H ( SEQ ID NO : 63 )

[0054] A human LILRB2 polypeptide sequence is available under UniProt Accession No. Q8N423, as shown below:MTPIVTVLICLGLSLGPRTRVQTGTIPKPTLWAEPDSVITQGSPVTLSCQGSLEAQEYR LYREKKSASWITRIRPELVKNGQFHIPSITWEHTGRYGCQYYSRARWSELSDPLVLVMTGAYPKPTLSAQPSPVVTSGGRVTLQCESQVAFGGFILCKEGEDEHPQCLNSQPHARGSSRAI FSVGPVSPNRRWSHRCYGYDLNSPYVWSSPSDLLELLVPGVSKKPSLSVQPGPVMA PGESLTLQCVSDVGYDRFVLYKEGERDLRQLPGRQPQAGLSQANFTLGPVSRSYGGQYR CYGAHNLSSECSAPSDPLDILITGQIRGTPFISVQPGPTVASGENVTLLCQSWRQFHTF LLTKAGAADAPLRLRSIHEYPKYQAEFPMSPVTSAHAGTYRCYGSLNSDPYLLSHPSEP LELVVSGPSMGSSPPPTGPISTPGPEDQPLTPTGSDPQSGLGRHLGVVIGILVAVVLLL LLLLLLFLILRHRRQGKHWTSTQRKADFQHPAGAVGPEPTDRGLQWRSSPAADAQEENL YAAVKDTQPEDGVEMDTRAAASEAPQDVTYAQLHSLTLRRKATEPPPSQEREPPAEPSI YATLAIH ( SEQ ID NO : 64 )

[0055] The term “antibody” (Ab) or “immunoglobulin” (Ig), as used herein, refers to a tetramer comprising two heavy chains (HCs) (about 50-70 kDa) and two light chains (LCs) (about 25 kDa) inter-connected by disulfide bonds. Each heavy chain is comprised of a heavy chain variable domain (VH) and a heavy chain constant region (CH). Each light chain is composed of a light chain variable domain (VL) and a light chain constant region (CL). The VH and VL domains can be subdivided further into regions of hypervariability, termed “complementarity determining regions” (CDRs), interspersed with regions that are more conserved, termed “framework regions” (FRs). Each VH and VL is composed of three CDRs (H-CDR herein designates a CDR from the heavy chain; and L-CDR herein designates a CDR from the light chain) and four FRs, arranged from amino-terminus to carboxyl-terminus in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4. The assignment of amino acid numbers, and of FR and CDR regions, in the heavy or light chain may be in accordance with IMGT® definitions (Lefranc et al., Dev Comp Immunol. (2003) 27(l):55-77); or the definitions of Kabat, Sequences of Proteins of Immunological Interest (National Institutes of Health, Bethesda, MD (1987 and 1991)); Chothia & Lesk, J Mol Biol (1987) 196:901-17; Chothia et al., Nature (1989) 342:878-83; MacCallum et al., J Mol Biol. (1996) 262:732-45; or Honegger and Pliickthun, J Mol Biol. (2001) 309(3):657-70.

[0056] The term “recombinant antibody” refers to a non-naturally occurring antibody that is expressed from a cell or cell line comprising the nucleotide sequence(s) that encode the antibody, wherein said nucleotide sequence(s) are not naturally associated with the cell.

[0057] The term “isolated protein,” “isolated polypeptide” or “isolated antibody” refers to a protein, polypeptide or antibody that by virtue of its origin or source of derivation (1) is not associated with naturally associated components that accompany it in its native state, (2) is free of other proteins from the same species, (3) is expressed by a cell from a differentspecies, and / or (4) does not occur in nature. Thus, a polypeptide that is chemically synthesized or synthesized in a cellular system different from the cell from which it naturally originates will be “isolated” from its naturally associated components. A protein may also be rendered substantially free of naturally associated components by isolation, using protein purification techniques well known in the art. Such naturally associated components may include, e.g., nucleic acids, proteins, other antibodies or antigen-binding fragments, lipids, carbohydrates, cellular debris, growth medium, etc.

[0058] The term “affinity” refers to a measure of the attraction between an antigen and an antibody. The intrinsic attractiveness of the antibody for the antigen is typically expressed as the binding affinity equilibrium constant (KD) of a particular antibody-antigen interaction. An antibody is said to specifically bind to an antigen when the KD for the binding is < 1 pM, e.g., < 100 nM or < 10 nM. A KD binding affinity constant can be measured, e.g., by surface plasmon resonance (Biacore™) using the Biacore™ T200 system, the IBIS MX96 SPR system from IBIS Technologies, or the Carterra LSA SPR platform, or by bio-layer interferometry, for example using the Octet™ system from ForteBio.

[0059] The term “epitope” as used herein refers to a portion (determinant) of an antigen that is bound by an antigen-binding protein (e.g., an antibody or an antigen-binding portion thereof). For example, an epitope may refer to the portion of an antigen that specifically binds to an antigen-binding site of an antigen-binding protein (e.g., an antibody or antigenbinding portion thereof), wherein the antigen-binding site is known as a paratope. Epitopic determinants generally consist of chemically active surface groupings of molecules such as amino acids or carbohydrate or sugar side chains and generally have specific three- dimensional structural characteristics, as well as specific charge characteristics. An antigen may have more than one epitope.

[0060] An epitope may be “linear” or “conformational.” In a linear epitope, all of the points of interaction between a protein (e.g., an antigen) and an interacting molecule (e.g., an antibody) occur linearly along the primary amino acid sequence of the protein. In a conformational epitope, the points of interaction occur across amino acid residues on the protein that are separated from one another in the primary amino acid sequence. A “functional” epitope refers to residues that directly contribute to the affinity of the antigen / antigen-binding protein interaction. Epitopes may be determined using methods such as, e.g., alanine scanning mutational analysis, peptide blot analysis, peptide cleavage analysis, crystallographic studies, NMR analysis, and hydrogen / deuterium exchange detected by mass spectrometry.

[0061] Once a desired epitope on an antigen is determined, it is possible to generate antibodies to that epitope using techniques well known in the art. For example, an antibody to a linear epitope may be generated, e.g., by immunizing an animal with a peptide having the amino acid residues of the linear epitope. An antibody to a conformational epitope may be generated, e.g., by immunizing an animal with a mini-domain containing the relevant amino acid residues of the conformational epitope. An antibody to a particular epitope can also be generated, e.g., by immunizing an animal with the target molecule of interest (e.g., LILRB1 or LILRB2) or a relevant portion thereof, then screening for binding to the epitope. An antibody to a particular epitope also may be generated using phage display methods.

[0062] One can determine whether an antibody binds to the same epitope as or competes for binding to LILRB1 and / or LILRB2 with an anti -LILRB 1 / 2 antibody of the present disclosure by using methods known in the art, including, without limitation, competition assays, epitope binning, and alanine scanning. In some embodiments, one allows the antibody of the present disclosure to bind to the antigen under saturating conditions, and then measures the ability of the test antibody to bind to that antigen. If the test antibody is able to bind to the antigen at the same time as the reference antibody, then the test antibody binds to a different epitope than the reference antibody. However, if the test antibody is not able to bind to the antigen at the same time, then the test antibody binds to the same epitope, an overlapping epitope, or an epitope that is in close proximity to the epitope bound by the antibody of the present disclosure. To test whether an antibody cross-competes with another antibody, one may use the competition method described above in two directions, i.e., determining if the known antibody blocks the test antibody and vice-versa. Competition or cross-competition experiments can be performed using, e.g., ELISA, RIA, Biacore™, SPR, Bio-Layer Interferometry or flow cytometry. For example, the experiments may be performed, e.g., using a Biacore™ T200, IBIS MX96, or Carterra LSA SPR instrument or the Octet™ system.

[0063] The term “human antibody” refers to an antibody in which the variable domains and constant region sequences are derived from human sequences. The term encompasses antibodies with sequences that are derived from human genes but have been modified, e.g., to decrease immunogenicity, increase affinity, and / or increase stability. Further, the term encompasses antibodies produced recombinantly in nonhuman cells, which may impart glycosylation not typical of human cells. The term also encompasses antibodies produced in transgenic nonhuman organisms with human antibody genes (e.g., OmniRat® rats).

[0064] The term “antigen-binding portion” or “antigen-binding fragment” of an antibody,or simply “antibody portion,” as used herein, refers to one or more portions or fragments of an antibody that retain the ability to specifically bind to an antigen (e.g., human LILRB1 and / or human LILRB2, or portion(s) thereof). It has been shown that certain fragments of a full-length antibody can perform the antigen-binding function of the antibody. Examples of binding fragments encompassed within the term “antigen-binding portion” include (i) a Fab fragment: a monovalent fragment consisting of the VL, VH, CL and CHI domains; (ii) a F(ab’)2 fragment: a bivalent fragment comprising two Fab fragments linked by a disulfide bridge at the hinge region; (iii) an Fd fragment consisting of the VH and CHI domains; (iv) an Fv fragment consisting of the VL and VH domains of a single arm of an antibody, (v) a dAb fragment, which consists of a VH domain; and (vi) an isolated complementarity determining region (CDR) capable of specifically binding to an antigen (e.g., a CDR3 peptide or a FR3-CDR3-FR4 peptide). Further, although the two domains of an Fv fragment, VL and VH, are encoded by separate genes, they can be joined, using recombinant methods, by a synthetic linker that enables them to be made as a single protein chain in which the VL and VH domains pair to form a monovalent molecule (known as single chain Fv (scFv)). Also within the present disclosure are antigen-binding molecules comprising a VH and / or a VL. In the case of a VH, the molecule may also comprise one or more of a CHI, hinge, CH2, or CH3 region. Such single chain antibodies are also intended to be encompassed within the term “antigen-binding portion” of an antibody. Other forms of single chain antibodies, such as diabodies, are also encompassed. Diabodies are bivalent, bispecific antibodies in which VH and VL domains are expressed on a single polypeptide chain, but using a linker that is too short to allow for pairing between the two domains on the same chain, thereby forcing the domains to pair with complementary domains of another chain and creating two antigenbinding sites. Also contemplated are tribodies, tetrabodies, nanobodies (e.g., monovalent or bivalent nanobodies), minibodies, domain-specific antibodies, single domain antibodies, and domain-deleted antibodies.

[0065] Antigen-binding portions, such as Fab and F(ab’)2 fragments, can be prepared from whole antibodies using conventional techniques, such as papain or pepsin digestion of whole antibodies. Moreover, antibodies, antigen-binding portions and immunoadhesin molecules can be obtained using standard recombinant DNA techniques, e.g., as described herein.

[0066] The class (isotype) and subclass of anti -LILRB 1 / 2 antibodies described herein may be determined by any method known in the art. In general, the class and subclass of an antibody may be determined using antibodies that are specific for a particular class andsubclass of antibody. Such antibodies are available commercially. The class and subclass can be determined by ELISA or Western blot as well as other techniques. Alternatively, the class and subclass may be determined by sequencing all or a portion of the constant regions of the heavy and / or light chains of the antibodies, comparing their amino acid sequences to the known amino acid sequences of various classes and subclasses of immunoglobulins, and determining the class and subclass of the antibodies.

[0067] Unless otherwise indicated, the numbering of all antibody amino acid residues in this disclosure is according to the IMGT® numbering scheme.I. Anti-LILRBl / 2 Antibodies and Binding Proteins

[0068] The present disclosure provides anti -LILRB 1 / 2 antibodies and antigen-binding portions thereof, as well as binding proteins comprising said antibodies or antigen-binding portions. In a certain aspect, the antibodies disclosed herein are human antibodies generated from transgenic animals (e.g., rats) that are able to produce antibodies encoded by rearranged human antibody genes. In particular embodiments, the human antibodies may contain certain mutations, e.g., to change primer-derived mutations back to the germline sequence.

[0069] In some embodiments, the anti -LILRB 1 / 2 antibodies of the present disclosure have the “LALA” mutations (L234A / L235A) in the Fc region. These mutations hinder binding of the antibodies to human FcyR (Fc gamma receptors). Such antibodies are advantageous because they have a low level of secondary effector functions and hence do not deplete effector T cells or target other non-malignant cells.

[0070] In some embodiments, the anti -LILRB 1 / 2 antibody or antigen-binding portion competes or cross-competes for binding to human LILRB 1 and / or LILRB2 with, or binds to the same epitope of human LILRB 1 and / or LILRB2 as, an antibody comprising: a) an HC comprising the amino acid sequences of SEQ ID NOs: 3 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 4 and 62; b) an HC comprising the amino acid sequences of SEQ ID NOs: 13 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 14 and 62; c) an HC comprising the amino acid sequences of SEQ ID NOs: 23 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 24 and 62; d) an HC comprising the amino acid sequences of SEQ ID NOs: 33 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 34 and 62; or e) an HC comprising the amino acid sequences of SEQ ID NOs: 43 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 44 and 62.

[0071] In some embodiments, the anti-LILRB 1 / 2 antibody or antigen-binding portion has an H-CDR3 amino acid sequence of SEQ ID NO: 7, 17, 27, 37, or 47.

[0072] In some embodiments, the anti-LILRB 1 / 2 antibody or antigen-binding portion has H-CDR1-3 comprising the amino acid sequences of SEQ ID NOs: 5-7, 15-17, 25-27, 35-37, or 45-47, respectively.

[0073] In some embodiments, the anti-LILRB 1 / 2 antibody or antigen-binding portion has a VH amino acid sequence that is at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to the amino acid sequence of SEQ ID NO: 3, 13, 23, 33, or 43.

[0074] In some embodiments, the anti-LILRB 1 / 2 antibody or antigen-binding portion has a VH comprising the amino acid sequence of SEQ ID NO: 3, 13, 23, 33, or 43.

[0075] In some embodiments, the anti-LILRB 1 / 2 antibody has a VH amino acid sequence that is at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to the amino acid sequence of SEQ ID NO: 3, 13, 23, 33, or 43; and a heavy chain constant region amino acid sequence that is at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to the amino acid sequence of SEQ ID NO: 61.

[0076] In some embodiments, the anti-LILRB 1 / 2 antibody comprises a VH amino acid sequence of SEQ ID NO: 3, 13, 23, 33, or 43, and a heavy chain constant region amino acid sequence of SEQ ID NO: 61.

[0077] In some embodiments, the anti-LILRB 1 / 2 antibody or antigen-binding portion has an L-CDR3 amino acid sequence of SEQ ID NO: 10, 20, 30, 40, or 50.

[0078] In some embodiments, the anti-LILRB 1 / 2 antibody or antigen-binding portion has L-CDR1-3 comprising the amino acid sequences of SEQ ID NOs: 8-10, 18-20, 28-30, 38-40, or 48-50, respectively.

[0079] In some embodiments, the anti-LILRB 1 / 2 antibody or antigen-binding portion has a VL amino acid sequence that is at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to the amino acid sequence of SEQ ID NO: 4, 14, 24, 34, or 44.

[0080] In some embodiments, the anti-LILRB 1 / 2 antibody or antigen-binding portion has a VL comprising the amino acid sequence of SEQ ID NO: 4, 14, 24, 34, or 44.

[0081] In some embodiments, the anti-LILRB 1 / 2 antibody has a VL amino acid sequence that is at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to the amino acid sequence of SEQ ID NO: 4, 14, 24, 34, or 44; and a light chain constant region amino acid sequence that is at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to the amino acid sequence of SEQ ID NO: 62.

[0082] In some embodiments, the anti-LILRB 1 / 2 antibody comprises a VL amino acidsequence of SEQ ID NO: 4, 14, 24, 34, or 44 and a light chain constant region amino acid sequence of SEQ ID NO: 62.

[0083] In certain embodiments, the anti -LILRB 1 / 2 antibody comprises any one of the above-described heavy chains and any one of the above-described light chains.

[0084] In some embodiments, the anti -LILRB 1 / 2 antibody or antigen-binding portion of the present disclosure comprises the H-CDR1-3 and L-CDR1-3 amino acid sequences of: a) SEQ ID NOs: 5-10, respectively; b) SEQ ID NOs: 15-20, respectively; c) SEQ ID NOs: 25-30, respectively; d) SEQ ID NOs: 35-40, respectively; or e) SEQ ID NOs: 45-50, respectively.

[0085] In some embodiments, the anti -LILRB 1 / 2 antibody or antigen-binding portion of the present disclosure comprises a VH and a VL that are 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical (e.g., 90% identical) to the amino acid sequences of: a) SEQ ID NOs: 3 and 4, respectively; b) SEQ ID NOs: 13 and 14, respectively; c) SEQ ID NOs: 23 and 24, respectively; d) SEQ ID NOs: 33 and 34, respectively; or e) SEQ ID NOs: 43 and 44, respectively.

[0086] In some embodiments, the anti -LILRB 1 / 2 antibody or antigen-binding portion of the present disclosure comprises a VH and a VL that comprise the amino acid sequences of: a) SEQ ID NOs: 3 and 4, respectively; b) SEQ ID NOs: 13 and 14, respectively; c) SEQ ID NOs: 23 and 24, respectively; d) SEQ ID NOs: 33 and 34, respectively; or e) SEQ ID NOs: 43 and 44, respectively.

[0087] In some embodiments, the anti -LILRB 1 / 2 antibody of the present disclosure comprises: a) an HC comprising the amino acid sequences of SEQ ID NOs: 3 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 4 and 62; b) an HC comprising the amino acid sequences of SEQ ID NOs: 13 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 14 and 62; c) an HC comprising the amino acid sequences of SEQ ID NOs: 23 and 61 and anLC comprising the amino acid sequences of SEQ ID NOs: 24 and 62; d) an HC comprising the amino acid sequences of SEQ ID NOs: 33 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 34 and 62; or e) an HC comprising the amino acid sequences of SEQ ID NOs: 43 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 44 and 62.

[0088] The present disclosure also provides an anti -LILRB 1 / 2 antibody or an antigenbinding portion thereof that competes or cross-competes for binding to LILRB 1 and / or LILRB2 with, or binds to the same epitope of LILRB 1 and / or LILRB2 as, antibody 28425.30976, 28425.34436, 28425.30983, 27878.30934, or 28107.30969.

[0089] In some embodiments, the anti -LILRB 1 / 2 antibody or antigen-binding portion of the present disclosure comprises the H-CDR1-3 and L-CDR1-3 amino acid sequences of antibody 28425.30976, 28425.34436, 28425.30983, 27878.30934, or 28107.30969.

[0090] In some embodiments, the anti -LILRB 1 / 2 antibody or antigen-binding portion of the present disclosure comprises a VH and a VL that are at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical in amino acid sequence to the VH and VL, respectively, of antibody 28425.30976, 28425.34436, 28425.30983, 27878.30934, or 28107.30969.

[0091] In some embodiments, the anti -LILRB 1 / 2 antibody or antigen-binding portion of the present disclosure comprises a VH and a VL that are the VH and VL, respectively, of antibody 28425.30976, 28425.34436, 28425.30983, 27878.30934, or 28107.30969.

[0092] In some embodiments, the anti -LILRB 1 / 2 antibody of the present disclosure is antibody 28425.30976, 28425.34436, 28425.30983, 27878.30934, or 28107.30969, or an antibody with the same amino acid sequences as said antibody.

[0093] Also contemplated by the present disclosure is an anti-LILRB2 antibody or an antigen-binding portion thereof, wherein said anti-LILRB2 antibody- competes or cross-competes for binding to human LILRB2 with, or binds to the same epitope of human LILRB2 as, an antibody comprising an HC comprising the amino acid sequences of SEQ ID NOs: 53 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 54 and 62;- comprises the H-CDR1-3 and L-CDR1-3 amino acid sequences of SEQ ID NOs: 55-60, respectively;- comprises a VH and a VL that are 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical (e.g., 90% identical) to the amino acid sequences of SEQ ID NOs: 53 and 54, respectively;- comprises a VH and a VL that comprise the amino acid sequences of SEQ ID NOs: 53 and 54, respectively; or- comprises an HC comprising the amino acid sequences of SEQ ID NOs: 53 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 54 and 62.In some embodiments, the anti-LILRB2 antibody- competes or cross-competes for binding to LILRB2 with, or binds to the same epitope of LILRB2 as, antibody 28188.30971;- comprises the H-CDR1-3 and L-CDR1-3 amino acid sequences of antibody 28188.30971;- comprises a VH and a VL that are at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical in amino acid sequence to the VH and VL, respectively, of antibody 28188.30971;- comprises a VH and a VL that are the VH and VL, respectively, of antibody 28188.30971; or- is antibody 28188.30971, or an antibody with the same amino acid sequences as said antibody.In some embodiments, it is contemplated that an embodiment (or combination of embodiments) herein referring to an anti -LILRB 1 / 2 antibody described herein may also apply to an anti-LILRB2 antibody described herein.

[0094] In some embodiments, a “variant” antibody or antigen-binding portion, having amino acid substitutions (which may be conservative or non-conservative) from an antibody or antigen-binding portion exemplified herein, does not have substantially altered biologic activity from the exemplified antibody or antigen-binding portion. For example, the variant antibody or antigen-binding portion may retain at least 50%, 70%, 75%, 80%, 85%, 90%, 95%, or 100% of the binding affinity of the parent antibody or antigen-binding portion, or may exceed the binding affinity of the parent antibody or antigen-binding portion. In some embodiments, a variant antibody or an antigen-binding portion thereof may have mutations, e.g., that increase its half-life, alter its immunogenicity, provide a site for covalent or non- covalent binding to another molecule, etc. In certain embodiments, the variant antibody or antigen-binding portion thereof may have mutations in its FRs (e.g., in one, two, three, four, five, six, seven, or eight of its FRs). In certain embodiments, the variant antibody or antigenbinding portion thereof may have mutations in its CDRs (e.g., in one, two, three, four, five, or six of its CDRs). In certain embodiments, the variant antibody or antigen-binding potion thereof may have mutations in its constant regions.

[0095] The class of an anti -LILRB 1 / 2 antibody described herein may be changed orswitched with another class or subclass. In some embodiments of the present disclosure, a nucleic acid molecule encoding the VL or VH of the antibody is isolated using methods well known in the art such that it does not include nucleic acid sequences encoding CL or CH, respectively. The nucleic acid molecules encoding VL or VH then are operatively linked to a nucleic acid sequence encoding a CL or CH, respectively, from a different class or subclass of immunoglobulin molecule. This may be achieved using a vector or nucleic acid molecule that comprises a CL or CH sequence, as described above. For example, an anti -LILRB 1 / 2 antibody that was originally IgM may be class switched to IgG. Further, the class switching may be used to convert one IgG subclass to another, e.g., from IgGi to IgG?. A K light chain constant region can be changed, e.g., to a light chain constant region, or vice-versa.

[0096] The anti -LILRB 1 / 2 antibody of the present disclosure can be an IgG, an IgM, an IgE, an IgA, or an IgD molecule, but is typically of the IgG isotype, e.g., of IgG subclass IgGi, IgG?aor IgG?b, IgGs or IgG4. In some embodiments, the antibody is of the isotype subclass IgGi.

[0097] In some embodiments, the anti -LILRB 1 / 2 antibody may comprise at least one mutation in the Fc region. A number of different Fc mutations are known, where these mutations alter, e.g., the antibody’s effector functions or half-life. For example, in some embodiments, the anti -LILRB 1 / 2 antibody comprises at least one mutation in the Fc region that reduces effector function.

[0098] In some embodiments, e.g., where the antibody is of the IgGi subclass, one or both of the amino acid residues at positions 234 and 235 may be mutated, for example, from Leu to Ala (L234A / L235A). These mutations reduce effector function of the Fc region of IgGi antibodies. The amino acid positions are numbered according to the Eu numbering scheme.

[0099] In some embodiments, e.g., where the antibody is of the IgG4 subclass, it may comprise the mutation S228P, where the amino acid position is numbered according to the Eu numbering scheme. This mutation is known to reduce undesired Fab arm exchange.

[0100] In some embodiments, the anti -LILRB 1 / 2 antibody or antigen-binding portion of the present disclosure is antagonistic.

[0101] In some embodiments, the anti -LILRB 1 / 2 antibody binds to human LILRB 1 with a KDof 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 1, 2, 3, 4, or 5 nM or less as measured by surface plasmon resonance.

[0102] In some embodiments, the anti -LILRB 1 / 2 antibody or antigen-binding portion binds to human LILRB2 with a KD of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 18, 20, or25 nM or less as measured by surface plasmon resonance.

[0103] In some embodiments, the anti-LILRB 1 / 2 antibody or antigen-binding portion binds to human LILRB1 with an ECso of 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.15, 0.2, 0.3, 0.4, or 0.5 nM or less as measured by ELISA.

[0104] In some embodiments, the anti-LILRB 1 / 2 antibody or antigen-binding portion binds to human LILRB2 with an ECso of 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.15, 0.2, 0.3, 0.4, or 0.5 nM or less as measured by ELISA.

[0105] In some embodiments, the anti-LILRB 1 / 2 antibody or antigen-binding portion binds to other human LILRA1, LILRA2, and / or LILRA3, alone or in any combination. For example, in certain embodiments, the anti-LILRB 1 / 2 antibody or antigen-binding portion may bind to human LILRA1 with a KD of 0.1, 0.2, 0.3 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, or 2 nM or less, bind to human LILRA2 with a KD of 5, 10, 15, 20, 25, or 30 nM or less, and / or bind to human LILRA3 with a KD of 0.5, 0.7, 0.9, 1, 1.1, 1.2, 1.3, 1.4, or 1.5 nM or less, as measured by surface plasmon resonance (SPR).

[0106] In some embodiments, the anti-LILRB 1 / 2 antibody or antigen-binding portion does not bind to any, or any combination, of human LILRB3, LILRB4, LILRB5, LILRA4, LILRA5, and LILRA6.

[0107] In some embodiments, the anti-LILRB 1 / 2 antibody or antigen-binding portion binds to LILRB1, LILRB2, and LILRA1-3, or any combination thereof, expressed on CHO-S cells. In certain embodiments, the anti-LILRB 1 / 2 antibody or antigen-binding portion binds to all or any combination of said antigens with an efficacy (MFI) of at least 50000, 100000, 150000, 200000, 250000, 300000, 350000, 400000, 450000, or 500000. In certain embodiments, the anti-LILRB 1 / 2 antibody or antigen-binding portion binds to all or any combination of said antigens with an ECso of 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, or 0.3 nM or less.

[0108] In some embodiments, the anti-LILRB 1 / 2 antibody or antigen-binding portion does not bind to rhesus, marmoset, or cynomolgus LILRB1 (e.g., expressed on CHO-S cells). In some embodiments, the anti-LILRB 1 / 2 antibody or antigen-binding portion does not bind to marmoset, or cynomolgus LILRB1 (e.g., expressed on CHO-S cells).

[0109] In some embodiments, the anti-LILRB 1 / 2 antibody or antigen-binding portion binds to all, or any combination, of rhesus LILRA1, LILRA2, and LILRA3, cynomolgus LILRA2 and LILRA3, and marmoset LILRA. In some embodiments, the anti-LILRB 1 / 2 antibody or antigen-binding portion binds to all, or any combination, of rhesus LILRA1, LILRA2, and LILRA3, cynomolgus LILRA2, and cynomolgus LILRA3.

[0110] In some embodiments, the anti-LILRBl / 2 antibody or antigen-binding portion binds to all, or any combination, of LILRB1 polymorphic variants L45P, Il 19T, S 1321, L45P / I119T, L45P / I119T / S132I, and A70P / L45P / I119T / S132I (e.g., expressed on CHO-S cells).[OHl] In some embodiments, the anti-LILRBl / 2 antibody or antigen-binding portion binds to an epitope in domain 1 of human LILRB1. In certain embodiments, the epitope does not include amino acids of LILRB1 on its interacting surface with HLA-G1. In some embodiments, the epitope comprises amino acid residues G19, P21, W46, R49, 150, P51, F60, P63, S64, and H69. In some embodiments, the epitope comprises El 1-R25, and optionally further comprises R36-165 or K41-165. In certain embodiments, the epitopes are determined using the methods described in Example 9 below. In certain embodiments, the anti -LILRB 1 / 2 antibody or antigen-binding portion binds to a different epitope of human LILRB1 than anti -LILRB 1 / 2 antibody NGM707 or anti -LILRB 1 antibody BND-22. In certain embodiments, the epitope does not comprise amino acid residues K41, R84, W67, A98, Y99, 1100, and VI 26, or any combination thereof, of LILRB 1.

[0112] In some embodiments, the anti-LILRBl / 2 antibody or antigen-binding portion binds to all, or any combination, of CD20+B cells, CD14+monocytes, and CD56+NK cells (e.g., in human primary PBMC), and CD8+T cells. In some embodiments, the anti- LILRB1 / 2 antibody or antigen-binding portion shows superior binding to one or more, or all, of these cell types, over MK-4830, NGM707, and BND-22, or any combination thereof.

[0113] In some embodiments, the anti-LILRBl / 2 antibody or antigen-binding portion blocks LILRB 1 binding to HLA-G / B2M and / or HLA-A2 / B2M (e.g., expressed on CHO-S cells). In certain embodiments, at a concentration of 100 nM, the anti -LILRB 1 / 2 antibody or antigen-binding portion inhibits LILRB 1 binding to HLA-G / B2M and / or HLA-A2 / B2M by at least 95, 96, 97, 98, or 99%, or by 100%.

[0114] In some embodiments, the anti -LILRB 1 / 2 antibody or antigen-binding portion blocks LILRB2 binding to HLA-G / B2M and HLA-A2 / B2M (e.g., expressed on CHO-S cells). In certain embodiments, at a concentration of 100 nM, the anti -LILRB 1 / 2 antibody or antigen-binding portion inhibits LILRB2 binding to HLA-G / B2M and / or HLA-A2 / B2M by at least 95, 96, 97, 98, or 99%, or by 100%.

[0115] In some embodiments, the anti-LILRBl / 2 antibody or antigen-binding portion enhances cytolytic NK cell activity (e.g., using the methods described in Example 11). In some embodiments, the anti-LILRBl / 2 antibody or antigen-binding portion increases tumor cell killing by NK cells. In certain embodiments, the anti-LILRBl / 2 antibody or antigen-binding portion induces tumor cell killing with superior potency compared to NGM707. In certain embodiments, the anti-LILRBl / 2 antibody or antigen-binding portion induces tumor cell killing with superior potency and efficacy compared to MK-4830. In some embodiments, the anti -LILRB 1 / 2 antibody or antigen-binding portion enhances tumor cell killing at an EC50 of 0.5, 0.7, 0.8, 0.9, 1.0, 1.2, 1.5, 1.7, 1.9, 2, 2.2, 2.5, 2.7, or 3 nM or less. In some embodiments, the anti-LILRBl / 2 antibody or antigen-binding portion enhances tumor cell killing with an efficacy of at least 5, 10, 15, 20, 25, or 30%.

[0116] In some embodiments, the anti-LILRBl / 2 antibody or antigen-binding portion increases secretion of TNFa and GM-CSF (e.g., by 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, or 1000%), and / or reduces secretion of IL-10 (e.g., by 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100%), in a PBMC / LPS assay (e.g., as described in Example 13).

[0117] In some embodiments, the anti-LILRBl / 2 antibody or antigen-binding portion increases secretion of TNFa, IFNy, and GM-CSF (e.g., by 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, or 1000%), and / or reduces secretion of IL-6 (e.g., by 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100%), in a PBMC / anti-CD3 assay (e.g., as described in Example 14).

[0118] In some embodiments, the anti-LILRBl / 2 antibody or antigen-binding portion enhances macrophage phagocytosis of HLA-G-expressing cells. In certain embodiments, the anti-LILRBl / 2 antibody or antigen-binding portion potentiates anti-CD47-mediated antibody-dependent cellular phagocytosis (ADCP).

[0119] In some embodiments, the anti-LILRBl / 2 antibody or antigen-binding portion increases secretion of TNFa and IFNy (e.g., by 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, or 1000%) in a mixed lymphocyte reaction (MLR) assay (e.g., as described in Example 15). In certain embodiments, the anti -LILRB 1 / 2 antibody or antigen-binding portion modulates (e.g., increases) CD4+T lymphocyte activation and cytokine responses initiated by M2 -polarized CD14+monocyte derived macrophages.

[0120] In some embodiments, the anti-LILRBl / 2 antibody or antigen-binding portion increases proliferation and activation of CD4+T cells in an MLR assay (e.g., by 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, or 1000%) (e.g., as described in Example 15). In certain embodiments, the anti -LILRB 1 / 2 antibody or antigen-binding portion upregulates intracellular Ki67 expression levels, CD25 expression levels, HLA-D4 expression levels, or any combination thereof (e.g., by 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, or 1000%). In some embodiments, the anti-LILRBl / 2 antibody or antigen-binding portion disrupts macrophage-mediated suppression of allogeneic T cell effector functions.

[0121] In some embodiments, the anti-LILRBl / 2 antibody or antigen-binding portiondemonstrates full occupancy of LILRB1 and / or LILRB2 (e.g., LILRB1 and LILRB2) at Q3W and Q4W in a two-compartment pharmacokinetic model with linear elimination kinetics (e.g., as described in Example 16). In particular embodiments, the anti -LILRB 1 / 2 antibody or antigen-binding portion thus is suitable for administration at Q3W or Q4W (e.g., at Q4W). Dosing at Q3W, or particularly Q4W, may provide significant advantages for cost, patient compliance, etc. over regimens requiring more frequent dosing.

[0122] In some embodiments, administration of a dose (e.g., 200 mg) of the anti- LILRB 1 / 2 antibody or antigen-binding portion results in higher plasma concentration in a subject than the same dose of NGM707.

[0123] The present disclosure also contemplates an anti -LILRB 1 / 2 or antigen-binding portion thereof with any combination of the above properties.

[0124] In some embodiments, an anti -LILRB 1 / 2 antibody or antigen-binding portion described herein has at least one (e.g., any 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, or 23) of the following properties: a) binds to human LILRB 1 with a KD of 0.1 nM or less as measured by surface plasmon resonance (SPR); b) binds to human LILRB2 with a KD of 10 nM or less as measured by surface plasmon resonance (SPR); c) binds to human LILRB 1 with an ECso of 0.1 nM or less as measured by ELISA; d) binds to human LILRB2 with an ECso of 0.2 nM or less as measured by ELISA; e) binds to human LILRA1 with a KD of 1 nM or less as measured by surface plasmon resonance (SPR); f) binds to human LILRA2 with a KD of 20 nM or less as measured by surface plasmon resonance (SPR); g) binds to human LILRA3 with a KD of 1.1 nM or less as measured by surface plasmon resonance (SPR); h) does not bind to human LILRB3, LILRB4, LILRB5, LILRA4, LILRA5, and LILRA6; i) does not bind to rhesus, marmoset, or cynomolgus LILRB 1 ; j) binds to rhesus LILRA1, LILRA2, and LILRA3, cynomolgus LILRA2 and LILRA3, and marmoset LILRA; k) binds to LILRB 1 polymorphic variants L45P, Il 19T, S132I, L45P / I119T, L45P / I119T / S132I, and A70P / L45P / I119T / S132I; l) binds to domain 1 of human LILRB 1 ;m) binds to a different epitope of human LILRB1 than anti -LILRB 1 / 2 antibody NGM707 or anti -LILRB 1 antibody BND-22; n) binds to CD20+B cells, CD14+monocytes, CD56+NK cells, and CD8+T cells; o) blocks LILRB 1 binding to HLA-G / B2M and HLA-A2 / B2M; p) blocks LILRB2 binding to HLA-G / B2M and HLA-A2 / B2M; q) enhances cytolytic NK cell activity; r) induces secretion of TNFa and GM-CSF, and / or reduces secretion of IL-10, in a PBMC / LPS assay; s) induces secretion of TNFa, IFNy, and GM-CSF, and / or limits secretion of IL-6, in a PBMC / anti-CD3 assay; t) enhances macrophage phagocytosis of HLA-G-expressing cells; u) increases secretion of TNFa and IFNy in a mixed lymphocyte reaction (MLR) assay; v) increases proliferation and activation of CD4+ T cells in an MLR assay; and w) demonstrates full LILRB 1 and LILRB2 receptor occupancy at Q3W and Q4W in a two-compartment pharmacokinetic model with linear elimination kinetics.

[0125] For example, in certain embodiments, an anti-LILRBl / 2 antibody or antigenbinding portion described herein may have properties a)-w) (e.g., antibody 28425.30976) or a)-s) (e.g., antibody 28425.34436).

[0126] In some embodiments, an anti -LILRB 1 / 2 antibody or antigen-binding portion described herein may enhance macrophage, NK cell, and / or T cell activity in a patient.

[0127] In some embodiments, an anti -LILRB 1 / 2 antibody or antigen-binding portion described herein may inhibit tumor growth and / or induce tumor growth regression in vivo. In some embodiments, an anti -LILRB 1 / 2 antibody or antigen-binding portion described herein may slow down or reverse metastasis in a cancer patient. In some embodiments, an anti- LILRB 1 / 2 antibody or antigen-binding portion described herein may prolong survival of a cancer patient. Any combination of the above properties is also contemplated.

[0128] The present disclosure also provides binding proteins that comprise all or an antigen-binding portion of an anti -LILRB 1 / 2 antibody described herein. In some embodiments, the anti -LILRB 1 / 2 antibody or antigen-binding portion is derivatized or linked to another molecule (e.g., another peptide or protein). In general, the antibodies or antigenbinding portions thereof are derivatized or linked such that antigen binding is not affected adversely by the derivatization or linking. Accordingly, the binding proteins of the present disclosure are intended to include both intact and modified forms of the anti -LILRB 1 / 2 antibodies or antigen-binding portions described herein. For example, an antibody or antigenportion of the present disclosure can be functionally linked (by chemical coupling, genetic fusion, noncovalent association or otherwise) to one or more other molecular entities, such as another antibody (e.g., a bispecific antibody), a label (e.g., a radioactively or fluorescently detectable marker), or a therapeutic agent (e.g., a cytotoxin or therapeutically useful radioisotope).

[0129] In some embodiments, the binding protein is a fusion protein, wherein the anti- LILRB 1 / 2 antibody or antigen-binding portion thereof is linked to another polypeptide. In certain embodiments, only the variable domains of the anti-LILRB 1 / 2 antibody are linked to the polypeptide. In certain embodiments, the VH domain of an anti-LILRB 1 / 2 antibody is linked to a first polypeptide, while the VL domain of an anti-LILRB 1 / 2 antibody is linked to a second polypeptide that associates with the first polypeptide in a manner such that the VH and VL domains can interact with each other to form an antigen-binding site. In some embodiments, the VH domain is separated from the VL domain by a linker such that the VH and VL domains can still interact with each other (e.g., single-chain antibodies). The VH- linker-VL antibody (e.g., an scFv) is then linked to the polypeptide of interest. In an scFv, the VH can be N-terminal or C-terminal to the VL, and the linker between them can be a flexible linker such as a Gly / Ser-rich linker. For example, the linker may contain one or more (e.g., 2, 3, 4, or 5) GGGGS (SEQ ID NO: 65) motifs.

[0130] In some embodiments, the binding protein is a multispecific (e.g., bispecific) binding molecule. The multispecific binding molecule has the binding specificity of an anti- LILRB 1 / 2 antibody described herein (e.g., may comprise the six CDRs or the VH and VL of said anti-LILRB 1 / 2 antibody). In some embodiments, the multispecific binding molecule additionally has the binding specificity of a) another, distinct anti-LILRB 1 / 2 antibody, e.g., an antibody that targets different epitope(s) on the same protein(s), or b) another, distinct antibody that targets a different protein, such as another cell surface molecule whose activity mediates the immune response or a disease condition such as cancer. Multispecific binding molecules are known in the art, and examples of different types of multispecific binding molecules (e.g., bispecific binding molecules) are given elsewhere herein.

[0131] In some embodiments, the binding protein is a fusion antibody or an immunoadhesin.

[0132] In some embodiments, the binding protein is an immunoconjugate, wherein the anti-LILRB 1 / 2 antibody or antigen-binding portion thereof is conjugated to another molecule, e.g., a therapeutic moiety. Examples of immunoconjugates include antibody-drug conjugates and antibody-toxin fusion proteins.

[0133] In some embodiments, the binding protein is a small modular immunopharmaceutical (SMIP).

[0134] In some embodiments, the binding protein is a chimeric antigen receptor (CAR). Such a CAR may be used in CAR-T therapy, in which T cells are engineered to express the CAR targeting LILRB1 and LILRB2.II. Nucleic Acid Molecules and Vectors

[0001] The present disclosure also provides nucleic acid molecules and sequences encoding anti -LILRB 1 / 2 antibodies or antigen-binding portions thereof described herein, or binding proteins described herein. In some embodiments, different nucleic acid molecules encode the heavy chain and light chain amino acid sequences of the anti -LILRB 1 / 2 antibody or antigen-binding portion. In other embodiments, the same nucleic acid molecule encodes the heavy chain and light chain amino acid sequences of the anti -LILRB 1 / 2 antibody or antigen-binding portion.

[0002] A reference to a nucleotide sequence encompasses its complement unless otherwise specified. Thus, a reference to a nucleic acid having a particular sequence should be understood to encompass its complementary strand, with its complementary sequence. The term “polynucleotide” as referred to herein means a polymeric form of nucleotides of at least 10 bases in length, either ribonucleotides or deoxynucleotides or a modified form of either type of nucleotide. The term includes single- and double-stranded forms.

[0003] In some embodiments, the present disclosure provides a nucleic acid molecule comprising a nucleotide sequence that encodes the heavy chain sequence, or a nucleotide sequence that encodes the light chain sequence, or both, of an anti -LILRB 1 / 2 antibody or antigen-binding portion thereof described herein. In some embodiments, the present disclosure provides a set (e.g., a pair) of nucleic acid molecules comprising a nucleotide sequence that encodes the heavy chain sequence, and a nucleotide sequence that encodes the light chain sequence, of an anti -LILRB 1 / 2 antibody or antigen-binding portion thereof described herein.

[0004] The present disclosure also provides nucleotide sequences that are at least 70%, 75%, 80%, 85%, 90%, 95%, 97%, 98% or 99% identical to one or more nucleotide sequences recited herein, e.g., to a nucleotide sequence selected from the group consisting of SEQ ID NOs: 1, 2, 11, 12, 21, 22, 31, 32, 41, and 42, or to a nucleotide sequence encoding an amino acid sequence selected from the group consisting of SEQ ID NOs: 3, 4, 13, 14, 23, 24, 33, 34, 43, and 44. The term “percent sequence identity” in the context of nucleic acid sequencesrefers to the residues in two sequences that are the same when aligned for maximum correspondence. The length of sequence identity comparison may be over a stretch of at least about nine nucleotides, usually at least about 18 nucleotides, more usually at least about 24 nucleotides, typically at least about 28 nucleotides, more typically at least about 32 nucleotides, and preferably at least about 36, 48, or more nucleotides. There are a number of different algorithms known in the art which can be used to measure nucleotide sequence identity. For instance, polynucleotide sequences can be compared using FASTA, Gap or Bestfit, which are programs in Wisconsin Package Version 10.0, Genetics Computer Group (GCG), Madison, Wisconsin. FASTA, which includes, e.g., the programs FASTA2 and FASTA3, provides alignments and percent sequence identity of the regions of the best overlap between the query and search sequences (see, e.g., Pearson, Methods Enzymol. (1990) 183:63-98; Pearson, Methods Mol. Biol. (2000) 132: 185-219; Pearson, Methods Enzymol. (1996) 266:227-58 (1996); and Pearson, J. Mol. Biol. (1998) 276:71-84; incorporated herein by reference).

[0005] In some embodiments, the present disclosure provides a nucleic acid molecule comprising a nucleotide sequence selected from the group consisting of SEQ ID NOs: 1, 2, 11, 12, 21, 22, 31, 32, 41, and 42. In certain embodiments, the nucleic acid molecule comprises the nucleotide sequences of SEQ ID NOs: 1 and 2, 11 and 12, 21 and 22, 31 and 32, or 41 and 42.

[0006] In any of the above embodiments, the nucleic acid molecules may be isolated. Nucleic acid molecules referred to herein as “isolated” or “purified” are nucleic acids which (1) have been separated away from the nucleic acids of the genomic DNA or cellular RNA of their source of origin; and / or (2) do not occur in nature.

[0007] In a further aspect, the present disclosure provides a vector suitable for expressing one or both of the chains of an antibody or antigen-binding portion thereof as described herein. The term “vector”, as used herein, means a nucleic acid molecule capable of transporting another nucleic acid to which it has been linked. In some embodiments, the vector is a plasmid, i.e., a circular double stranded piece of DNA into which additional DNA segments may be ligated. Moreover, certain vectors are capable of directing the expression of genes to which they are operatively linked. Such vectors are referred to herein as “recombinant expression vectors” (or simply, “expression vectors”).

[0008] The present disclosure provides vectors comprising nucleic acid molecules that encode the heavy chain sequence, the light chain sequence, or both the heavy and light chain sequences, of an anti-LILRB 1 / 2 antibody or antigen-binding portion thereof as describedherein. In certain embodiments, a vector of the present disclosure comprises a nucleic acid molecule described herein, or a pair or set of nucleic acid molecules described herein. The present disclosure further provides vectors comprising nucleic acid molecules encoding binding proteins, fusion proteins, modified antibodies, etc. as described herein. The vector may further comprise an expression control sequence.

[0009] The term “expression control sequence” as used herein means polynucleotide sequences that are necessary to effect the expression and processing of coding sequences to which they are ligated. Expression control sequences include appropriate transcription initiation, termination, promoter and enhancer sequences; efficient RNA processing signals such as splicing and polyadenylation signals; sequences that stabilize cytoplasmic mRNA; sequences that enhance translation efficiency (i.e., Kozak consensus sequence); sequences that enhance protein stability; and when desired, sequences that enhance protein secretion. The term “control sequences” is intended to include, at a minimum, all components whose presence is essential for expression and processing, and can also include additional components whose presence is advantageous, for example, leader sequences and fusion partner sequences.III. Making of Antibodies and Binding Proteins

[0135] The anti-LILRB 1 / 2 antibodies and antigen-binding portions thereof of the present disclosure, or related binding proteins as described herein, may be produced recombinantly using isolated nucleic acid molecules such as expression constructs. The encoding sequences for each polypeptide chain may be cloned into a single vector or cloned into separate vectors (e.g., a pair or set of vectors).

[0136] The antibodies or antigen-binding portions thereof or binding proteins may be produced in host cells, e.g., mammalian host cells, using appropriate expression constructs. Mammalian cell lines available as hosts for expression include many immortalized cell lines available from the American Type Culture Collection (ATCC). These include, inter alia, Chinese hamster ovary (CHO) cells, NS0 cells, SP2 cells, HEK-293T cells, 293 Freestyle cells (Invitrogen), NIH-3T3 cells, HeLa cells, baby hamster kidney (BHK) cells, African green monkey kidney cells (COS), human hepatocellular carcinoma cells (e.g., Hep G2), A549 cells, and a number of other cell lines. Other cell lines that may be used are insect cell lines, such as Sf9 or Sf21 cells, and yeast cell lines. In certain embodiments, the cell lines are not derived from a human embryo. Cell lines may be selected based on their expression levels. The antibodies, antigen-binding portions, or binding proteins may be isolated andpurified from the host cell culture using well known methods, such as centrifugation, ultracentrifugation, protein A, protein G, protein A / G, or protein L purification, and / or ion exchange chromatography.

[0137] In some embodiments, a host cell described herein comprises nucleic acid molecule(s) comprising a nucleotide sequence that encodes the heavy chain sequence, or a nucleotide sequence that encodes the light chain sequence, or both, of an anti-LILRB 1 / 2 antibody or antigen-binding portion thereof described herein. In some embodiments, the host cell comprises nucleic acid molecule(s) encoding both the heavy and light chain sequences. In some embodiments, the host cell comprises nucleic acid molecule(s) encoding only the heavy or light chain sequence, such chains being useful, e.g., as intermediates for the expression of an antibody or antigen-binding fragment that includes said heavy or light chain.

[0138] Host cells used to produce the antibodies, antigen-binding portions, or binding proteins are also termed “recombinant host cells.” A “recombinant host cell” (or simply “host cell”), as used herein, means a cell into which a recombinant expression construct has been introduced. By definition, a recombinant host cell does not occur in nature. A protein produced from a recombinant host cell is a recombinant protein.IV. Pharmaceutical Compositions

[0139] Another aspect of the present disclosure is a pharmaceutical composition comprising as an active ingredient (or as the sole active ingredient) an antibody or antigenbinding portion thereof or binding protein of the present disclosure. The pharmaceutical composition may additionally comprise a pharmaceutically acceptable excipient. A “pharmaceutically acceptable excipient” may include appropriate solvents, dispersion media, antibacterial and antifungal agents, isotonic agents, and the like. Examples of pharmaceutically acceptable excipients are water and saline (e.g., phosphate-buffered saline).

[0140] The pharmaceutical compositions herein may be used to enhance the immune response in a patient, or to treat cancer, e.g., cancer relating to LILRB1 and / or LILRB2- signaling.

[0141] A “therapeutically effective amount” is an amount of the agent (e.g., anti- LILRB 1 / 2 antibody or antigen-binding portion thereof or related binding protein) or a pharmaceutical composition comprising it that will relieve to some extent one or more of the symptoms of the disease being treated. A therapeutically effective amount of an anti-cancer therapeutic may, for example, result in delayed tumor growth, elimination of cancer cells, tumor shrinkage, increased survival, slowed or decreased metastasis, or other clinicalendpoints desired by healthcare professionals.

[0142] In some embodiments, the antibody or antigen-binding portion thereof or binding protein may be co-administered or formulated with another medication / drug, e.g., for enhancing the immune response or for treatment of cancer. The additional therapeutic treatment may comprise, e.g., an immunostimulatory agent, a vaccine, a chemotherapeutic agent, an anti -neoplastic agent, an anti -angiogenic agent, a corticosteroid, and / or radiation therapy. In some embodiments, the additional therapeutic treatment may comprise a different anti-cancer antibody or a different immune response-stimulating antibody.

[0143] The pharmaceutical compositions herein may be delivered to the patient through parenteral administration. In particular, parenteral administration is contemplated to include, but is not limited to, subcutaneous, intraperitoneal, intramuscular, intrastemal, intraci sternal, intravenous, intraarterial, intrathecal, intraurethral, intracranial, intratumoral, and intrasynovial injection or infusions. Particular embodiments include the intravenous route (e.g., intravenous infusion) and the subcutaneous route (e.g., subcutaneous injection).V. Therapeutic Uses

[0144] In some embodiments, the anti-LILRB 1 / 2 antibodies and antigen-binding portions thereof, compositions, and binding proteins of the present disclosure are used to enhance the immune response in a patient (e.g., a mammal such as a human) in need thereof. In certain embodiments, the patient is immune-suppressed. In certain embodiments, a physician can boost the anti-cancer activity of a patient’s own immune system by administering an anti- LILRB 1 / 2 antibody or antigen-binding portion thereof, composition, or binding protein as described herein. For example, a physician can boost anti -turn or activity in a patient by administering an anti-LILRB 1 / 2 antibody or antigen-binding portion, antibody composition, or binding protein of the present disclosure, alone or in combination with other therapeutic agents.

[0145] In certain embodiments, the antibodies or antigen-binding portions thereof, compositions, or binding proteins of the present disclosure are for use in the treatment of cancer. The cancer may be in one or more tissues such as skin, lung, intestine, colon, ovary, brain, prostate, kidney, soft tissues, the hematopoietic system, head and neck, liver, bone, bladder, breast, stomach, uterus, cervix, and pancreas.

[0146] In some embodiments, cancers treated by the anti-LILRB 1 / 2 antibodies, antigenbinding portions, compositions, and binding proteins of the present disclosure may include, e.g., melanoma, skin basal cell cancer, glioblastoma, glioma, gliosarcoma, astrocytoma,meningioma, neuroblastoma, adrenocortical cancer, head and neck squamous cell cancer, oral cancer, salivary gland cancer, nasopharyngeal cancer, breast cancer (e.g., triple negative breast cancer), lung cancer (e.g., non-small cell lung cancer (NSCLC), small cell lung cancer, and squamous cell lung cancer), esophageal cancer, gastroesophageal junction cancer, gastric cancer, gastrointestinal cancer, primary peritoneal cancer, liver cancer, hepatocellular carcinoma, gallbladder cancer, biliary tract cancer, cholangiocarcinoma, colon cancer, rectal cancer, colorectal carcinoma, ovarian cancer, fallopian tube cancer, bladder cancer, upper urinary tract cancer, urothelial cancer, renal cell carcinoma, kidney cancer, genitourinary cancer, cervical cancer, testicular cancer, prostate cancer, fibrosarcoma, liposarcoma, rhabdomyosarcoma, osteosarcoma, histiocytoma, pancreatic cancer, endometrial cancer, cancer of the appendix, thyroid cancer, advanced Merkel cell cancer, multiple myeloma, sarcomas, choriocarcinoma, leukemia (e.g., erythroleukemia, acute lymphoblastic leukemia, acute monocytic leukemia, acute promyelocytic leukemia, acute myeloid leukemia, chronic myeloid leukemia, chronic lymphocytic leukemia, acute lymphoblastic leukemia, or mast cell leukemia), lymphoma (e.g., small lymphocytic lymphoma, Burkitt’s lymphoma, Hodgkin’s lymphoma, non-Hodgkin’s lymphoma, diffuse large B cell lymphoma, follicular lymphoma, monocytic lymphoma, or HTLV-associated T cell leukemia / lymphoma), mesothelioma, and solid tumors. The cancer may be, e.g., at an early, intermediate, late, locally advanced, or metastatic stage, and may be relapsed or refractory to other therapeutics (e.g., other therapeutics targeting LILRB1 and / or LILRB2, or checkpoint inhibitors) or there may be no standard therapy available.

[0147] In some embodiments, conditions treated by the anti -LILRB 1 / 2 antibodies, antigen-binding portions, compositions, and binding proteins of the present disclosure may include, e.g., ovarian cancer (e.g., platinum-resistant ovarian cancer), squamous cell carcinoma (e.g., cutaneous squamous cell carcinoma), esophageal cancer (e.g., esophageal squamous cell carcinoma), breast cancer (e.g., triple-negative breast cancer), head and neck cancer (e.g., head and neck squamous cell carcinoma), lung cancer (e.g., non-small cell lung cancer), sarcoma (e.g., undifferentiated pleomorphic sarcoma or liposarcoma), biliary tract cancer (e.g., intra- and extra-hepatic biliary duct cancer), and gallbladder cancer.

[0148] In some embodiments, the antibodies or antigen-binding portions thereof, compositions, or binding proteins of the present disclosure are for use in the treatment of an immune disorder, e.g., by enhancing the immune response of a patient in need thereof. For example, the antibody or antigen-binding portion, composition, or binding protein may be used to treat a patient who is, or is at risk of being, immunocompromised (e.g., due tochemotherapeutic or radiation therapy, or after transplantation). In some embodiments, the antibody or antigen-binding portion, composition, or binding protein is for use in treating viral and / or parasitic infections, e.g., where the pathogens inhibit the host immune response.

[0149] Treat,” “treating,” and “treatment” refer to a method of alleviating or abrogating a biological disorder and / or at least one of its attendant symptoms. As used herein, to “alleviate” a disease, disorder or condition means reducing the severity and / or occurrence frequency of the symptoms of the disease, disorder, or condition. Further, references herein to “treatment” include references to curative, palliative and prophylactic treatment.

[0150] “Therapeutically effective amount” refers to the amount of the therapeutic agent being administered that will relieve to some extent one or more of the symptoms of the disorder being treated. A therapeutically effective amount of an anti-cancer therapeutic, for example, may result in delayed tumor growth, tumor shrinkage, increased survival, elimination of cancer cells, slowed or decreased disease progression, reversal of metastasis, or other clinical endpoints desired by healthcare professionals.

[0151] The anti -LILRB 1 / 2 antibodies or antigen-binding portions thereof, antibody compositions, or binding proteins of the present disclosure may be administered without additional therapeutic treatments, i.e., as a stand-alone therapy (monotherapy). Alternatively, treatment with the anti -LILRB 1 / 2 antibodies or antigen-binding portions thereof, antibody compositions, or binding proteins of the present disclosure may include at least one additional therapeutic treatment (combination therapy), e.g., another immunostimulatory agent, an anticancer agent (e.g., a chemotherapeutic agent, an anti -neoplastic agent, an anti -angiogenic agent, or a tyrosine kinase inhibitor), or a vaccine (e.g., a tumor vaccine).

[0152] As used herein, the terms “co-administration,” “co-administered” and “in combination with,” referring to the anti -LILRB 1 / 2 antibodies and antigen-binding portions thereof, antibody compositions, and binding proteins of the present disclosure with one or more other therapeutic agents, is intended to mean, and does refer to and include the following: a) simultaneous administration wherein the components of the combination are formulated together into a single dosage form which releases said components at substantially the same time to said patient, b) substantially simultaneous administration wherein the components of the combination are formulated apart from each other into separate dosage forms which are taken at substantially the same time by said patient, whereupon said components are released at substantially the same time to said patient, where each part may be administered by either thesame or a different route, c) sequential administration wherein the components of the combination are formulated apart from each other into separate dosage forms which are taken at consecutive times with a significant time interval between each administration, whereupon said components are released at substantially different times to said patient, where each part may be administered by either the same or a different route; and d) administration wherein the components of the combination are formulated together into a single dosage form which releases said components in a controlled manner whereupon they are concurrently, consecutively, and / or overlappingly released at the same and / or different times to said patient.

[0153] In some embodiments, the antibody or antigen-binding portion thereof, antibody composition, or binding protein may be used in combination with an agent that targets the PD-1 / PD-L1 signaling axis (e.g., inhibiting signaling ofPD-1 and / or PD-L1). In certain embodiments, the agent may be an anti-PD-1 or anti-PD-Ll antibody or an antigen-binding portion thereof. In some embodiments, the agent may be, e.g., nivolumab, pembrolizumab, cemiplimab, dostarlimab, retifanlimab, toripalimab, vopratelimab, spartalizumab, camrelizumab, sintilimab, tislelizumab, INCMGA00012, AMP -224, AMP0514, acrixolimab, atezolizumab, durvalumab, avelumab, KN035, cosibelimab, AUNP12, CA-170, or BMS- 986189.

[0154] In some embodiments, the antibody or antigen-binding portion thereof, antibody composition, or binding protein may be used in combination with an agent that targets (e.g., inhibits) NKG2A. In certain embodiments, the agent may be an anti-NKG2A antibody or an antigen-binding portion thereof. In some embodiments, the agent may be monalizumab, BMS-986315, or HY-0102.

[0155] It is understood that the antibodies and antigen-binding portions thereof, antibody compositions, and binding proteins of the present disclosure may be used in a method of treatment as described herein, may be for use in a treatment as described herein, and / or may be for use in the manufacture of a medicament for a treatment as described herein.VI. Diagnostic Uses

[0156] The antibodies and antigen-binding portions or binding proteins of the present disclosure also are useful in diagnostic processes (e.g., in vitro or ex vivo). For example, the antibodies, antigen-binding portions, or binding proteins can be used to detect and / or measure the level of LILRB1 and / or LILRB2 in a biological sample from a patient (e.g., a tumorbiopsy, a tissue sample, or a blood sample). Suitable detection and measurement methods include immunological methods such as flow cytometry, enzyme-linked immunosorbent assays (ELISA), chemiluminescence assays, radioimmunoassays, and immunohistochemistry. The present disclosure further encompasses kits (e.g., diagnostic kits) comprising the antibodies, antigen-binding portions, or binding proteins described herein.VII. Articles of Manufacture and Kits

[0157] The present disclosure also provides articles of manufacture, e.g., kits, comprising one or more containers (e.g., single-use or multi-use containers) containing a pharmaceutical composition of an anti -LILRB 1 / 2 antibody or antigen-binding portion thereof or binding protein described herein, optionally an additional therapeutic agent (which may be in the same or a separate pharmaceutical composition), and instructions for use. The antibody or antigen-binding portion or binding protein, and optional additional therapeutic agent, can be packaged separately in suitable packing such as a vial or ampule made from non-reactive glass or plastic. In certain embodiments, the vial or ampule holds a concentrated stock (e.g., 2x, 5x, lOx or more) of the antibody or antigen-binding portion, composition, or binding protein and optionally the additional therapeutic agent. In certain embodiments, the articles of manufacture such as kits include a medical device for administering the antibody or antigen-binding portion, composition, or binding protein and / or additional therapeutic agent (e.g., a syringe and a needle); and / or an appropriate diluent (e.g., sterile water and normal saline). The present disclosure also includes methods for manufacturing said articles.

[0158] Unless otherwise defined herein, scientific and technical terms used in connection with the present disclosure shall have the meanings that are commonly understood by those of ordinary skill in the art. Exemplary methods and materials are described below, although methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present disclosure. In case of conflict, the present specification, including definitions, will control. Further, unless otherwise required by context, singular terms shall include pluralities and plural terms shall include the singular. Throughout this specification and embodiments, the words “have” and “comprise,” or variations such as “has,” “having,” “comprises,” or “comprising,” will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. All publications and other references mentioned herein are incorporated by reference in their entirety, as if each individual reference were specifically and individuallyindicated to be incorporated by reference in its entirety. Although a number of documents are cited herein, this citation does not constitute an admission that any of these documents forms part of the common general knowledge in the art. As used herein, the term “approximately” or “about” as applied to one or more values of interest refers to a value that is similar to a stated reference value. In certain embodiments, the term refers to a range of values that fall within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, or less in either direction (greater than or less than) of the stated reference value unless otherwise stated or otherwise evident from the context.

[0159] According to the present disclosure, back-references in the dependent claims are meant as short-hand writing for a direct and unambiguous disclosure of each and every combination of claims that is indicated by the back-reference. Any compound disclosed herein can be used in any of the treatment method here, wherein the individual to be treated is as defined anywhere herein. Further, headers herein are created for ease of organization and are not intended to limit the scope of the claimed invention in any manner.

[0160] In order that this invention may be better understood, the following examples are set forth. These examples are for purposes of illustration only and are not to be construed as limiting the scope of the invention in any manner.EXAMPLESExample 1: Cloning of anti-LILRBl and LILRB2 antibodies from rat B cells

[0161] Antibodies against human LILRB1 and LILRB2 were isolated from an antibody repertoire derived from OmniRat® rats (Osborn et al., J Immunol. (2013) 190(4): 1481-90), a transgenic rat strain from Ligand Pharmaceuticals Inc. that produces antibodies with fully human idiotypes. Cloning of rat-derived antibody genes from single-cell sorted antibodysecreting B cells (ASCs) was performed by means of Symplex™ antibody discovery technology (Meijer et al., J Mol Biol (2006) 358(3):764-72) and additional antibodies were identified by selection of clonally related antibodies derived from lymph node RNA nextgeneration sequencing (NGS) samples.

[0162] Antibody repertoire constructs encoding fully human immunoglobulins in IgGi- LALA format (see below) were transfected into HEK293 cells. Secreted antibodies from cell supernatants were screened for binding to LILRB1 and LILRB2 expressed on the surface of transfected CHO cells using flow cytometry in a high-throughput format. LILRB1 and LILRB2 reactive clones were analyzed by DNA sequencing and antibody-encoding DNAsequences were extracted. Selected antibody clones were expressed and tested functionally as described below.

[0163] Missense mutations in the amino termini of heavy and light chains that were introduced by the use of degenerate primers in the Symplex™ cloning of the antibody - encoding cDNA fragments were corrected back to germline sequence. Table 1 shows the heavy and light chain variable domain nucleotide sequences of the germlined LILRB1 / 2- specific antibodies designated 28425.30976, 28425.34436, 28425.30983, 27878.30934, 28107.30969 and a LILRB2-specific antibody 28188.30971. The correction process involves amino terminal sequence correction to germline as well as codon usage optimization. The targets for matching to human germline sequences were identified by blast homology searches for the heavy chain and the light chain variable regions.

[0164] Protein sequences of the variable domains, the constant regions and the complementarity determining regions (CDRs) of LILRB1 / 2 specific antibodies 28425.30976, 28425.34436, 28425.30983, 27878.30934, 28107.30969 and the LILRB2-specific antibody 28188.30971 are shown in Table 2, Table 3 and Table 4, respectively.

[0165] Table 1 shows nucleotide sequences encoding the variable domains of antibodies 28425.30976, 28425.34436, 28425.30983, 27878.30934, 28107.30969 and 28188.30971.Table 1: Antibody Variable Domain Nucleotide Sequences

[0166] Table 2 shows the amino acid sequences of the variable domains of antibodies 28425.30976, 28425.34436, 28425.30983, 27878.30934, 28107.30969 and 28188.30971. CDRs are in bold / underlined.Table 2: Antibody Variable Domain Amino Acid Sequences

[0167] Table 3 shows heavy and light chain constant region amino acid sequences (CH and CL, respectively). “IgGi LALA” refers to the presence of “LALA” mutations in the heavy chain (L234A / L235A, numbered according to the Kabat numbering scheme) that are known to reduce effector function of the Fc region of IgGi antibodies (Hezareh et al., J Virol. (2001) 75(24): 12161-68; Hessell et al., Nature (2007) 449(7158): 101-4).Table 3: Antibody Constant Region Amino Acid Sequences

[0168] Table 4 shows heavy and light chain CDR amino acid sequences of antibodies 28425.30976, 28425.34436, 28425.30983, 27878.30934, 28107.30969 and 28188.30971, wherein the CDRs (SEQ ID NOs shown in parentheses below each sequence) are defined according to the IMGT® system.Table 4: Antibody CDR Amino Acid SequencesExample 2: Cloning of anti-LILRBl and / or LILRB2 reference antibody analogues

[0169] The amino acid sequences encoding the heavy and light chain variable domains of the antibody analogues in Table 5 were obtained from the listed patents or patent applications. The protein sequences were reverse-translated and codon-optimized for expression in CHO cells. The corresponding DNA sequences were gene synthesized and cloned into expression vectors containing human heavy or light chain constant regions, resulting in expression of full-length antibody chains. The human antibody isotype selected for expression is listed in the “Antibody Format” column in Table 5. CHO cells were transfected with the generated expression plasmids using a standard protein expression system. The corresponding antibody supernatants were purified using standard protein A chromatography.Table 5: Listing of Gene-Synthesized Antibody AnaloguesExample 3: Binding of anti-LILRBl / 2 antibodies to CHO-S cells transfected with human LILRB1-5 or LILRA1-6 receptors

[0170] Hamster CHO-S cells expressing human LILRB1, LILRB2, LILRB3, LILRB4, LILRB5, LILRA1, LILRA2, LILRA3, LILRA4, LILRA5, LILRA6 or mock control have been encoded using green (Cat. 90355, Sartorius) and violet (Cat. 97056, Sartorius) encoder dyes at different intensities to allow detection of each population seeded in the same well. The anti -LILRB 1 / 2 antibodies were incubated with hamster CHO-S cells transiently expressing human LILRB1, LILRB2, LILRB3, LILRB4, LILRB5, LILRA1, LILRA2, LILRA3, LILRA4, LILRA5 or LILRA6 receptors for 30 minutes at 4°C. The cells were washed twice and subsequently incubated for an additional 20 minutes with AF647-conjugated secondary anti-human IgG (H+L) antibody. After the washing step, antibody binding was detected using the high-throughput flow cytometer iQue3® (Sartorius) measuring the Geometric Mean (GeoMean) of AF647 signal in each well. Antibodies were serially diluted from 200 nM to 3 pM generating a 12-point curve and every concentration was analyzed in triplicate. Efficacy and EC50 values were calculated using GraphPad Prism 10 software.

[0171] Binding of the cross-reactive anti-LILRBl / 2 28425.30976 and 28425.34436 antibodies was investigated in CHO-S cells transiently expressing LILRB1-5 or LILRA1-6 proteins or mock controls. As seen in FIG. 1 and Table 6, the anti -LILRB 1 / 2 antibodies 28425.30976 and 28425.34436 bound to LILRB1 and LILRB2 and no other LILRB family members. Moreover, 28425.30976 and 28425.34436 bound to human LILRA1, LILRA2 and LILRA3 (FIG. 2; Table 6). Notably, differences in efficacy are in part related to different expression levels of the constructs in CHO cells (transfection controls not shown).Table 6: Efficacy and EC50 Values for Binding of Antibodies 28425.30976 and 28425.34436 to CHO-S cells Transfected with LILRB1-5 or LILRA1-6Data are shown as mean ± SD of triplicates.Example 4: Measurement of antibody affinities towards human LILRB1, LILRB2, LILRA1, LILRA2, and LILRA3

[0172] The anti -LILRB 1 / 2 antibodies were tested for binding to the extracellular domain of recombinant human LILRB 1 and LILRB2 and human LILRA1, LILRA2 and LILRA3 (ACRO Biosystems or R&D Systems) by SPR using Carterra LSA. An HC30M (Carterra)chip was functionalized by goat anti -human Ig Fc (Southern Biotech) using amine-coupling. The chip was activated by freshly prepared 0.4 M EDC, 0.1 M sulfo-NHS, and 0.1 M MES, pH 5.5 (1 : 1 : 1 v / v / v) for 5 min, coupled with 75 pg / mL anti-human Ig Fc in 10 mM sodium acetate, pH 4.5, for 10 min, and excess of reactive esters were quenched for 3 min by injection of 1 M ethanolamine, pH 8.5. The instrument was primed in running buffer (PBS pH 7.4, 0.01% Tween-20, 0.5 mg / ml BSA). After priming and washing, the antibodies were captured onto individual spots of the chip for 12 minutes as replicates (n=8). Kinetic analysis was performed by applying kinetic titration series of each LILRB antigen at increasing concentrations. Antigen association was performed for 5 minutes, and antigen dissociation was recorded for 20 minutes. After each cycle of antigen injections, the surface was regenerated by 0.45% H3PO4 for 2x20 s and washed for 5 min in running buffer. Binding responses were processed and analyzed using Carterra’s Kinetics™ software tool. Processed data was fitted to a simple Langmuir 1 : 1 binding model for calculation of the on-rate (konor ka), off-rate (koff or kd) and affinity (KD) constants.

[0173] Binding kinetics of antibodies 28425.30976, 28425.34436 and the BND-22, NGM707, and MK4830 analogues to recombinant human LILRB1, LILRB2, LILRA1, LILRA2 and LILRA3 are shown in Table 7. Antibodies 28425.30976 and 28425.34436 bound LILRB 1 and LILRB2 with high affinity, and cross-reacted with LILRA1, LILRA2 and LILRA3. The BND-22 analogue was confirmed to be specific for LILRB 1 but also showed cross-reactivity to LILRA1, and weak binding to LILRA2 and LILRA3. The NGM707 analogue showed cross-reactivity to all antigens except LILRA2, and the MK4830 analogue was shown to be specific for LILRB2.

[0174] In conclusion, 28425.30976 and 28425.34436 bind LILRB1 with picomolar affinity and LILRB2 with single-digit nanomolar affinity, and show cross-reactivity to LILRA1, LILRA2, and LILRA3 antigens.Table 7: Binding Kinetics of Antibodies to Human LILRB1, LILRB2, LILRA1, LILRA2 and LILRA3 as Measured by SPRData are presented as mean ± SD, n = 8. Values are kon: association constant; koff: dissociation constant; KD: equilibrium dissociation constant. N / A is not binding.Example 5: Measurement of antibody binding to human LILRB1 and LILRB2 using ELISA

[0175] The extracellular domain (ECD) of His-tagged recombinant human LILRB1 or LILRB2 (R&D Systems) was coated overnight on 96 well microtiter plates at 1.3 pg / mL (27 nM) in PBS with 0.05% Tween20 and 1% BSA.

[0176] The plates were then incubated for one hour with serial dilutions of anti-LILRB antibodies at the concentrations shown. Binding of anti-LILRB antibodies was detected with horseradish peroxidase (HRP)-conjugated goat anti-hlgG kappa / light chain polyclonal antibody (BioRad) and tetramethylbenzidine (TMB, KemEnTec) as substrate. A four- parameter nonlinear regression model was applied to the dose-response binding data to calculate the concentration of anti-LILRB antibodies yielding half maximum binding (ECso). The ECso values were used as an endpoint for evaluating the bivalent binding activity.

[0177] Antibodies 28425.30976, 28425.34436, and the NGM707 analogue (comparator) all bound with picomolar binding activity to recombinant human LILRB1 and LILRB2 as shown in FIG. 3 and Table 8. The EC50 values (Table 8) for the LILRB1 and LILRB2binding activity of antibodies 28425.30976 and 28425.34436 were 2-fold lower than that observed for the NGM707 analogue, indicating superior binding activity of antibodies 28425.30976 and 28425.34436. For all three antibodies, the binding activity to LILRB1 was higher than the binding activity to LILRB2.

[0178] Consistent with the binding to LILRB1 or LILRB2 transfected CHO cells (FIG. 1 and Table 6), the BND-22 analogue bound LILRB1 but not LILRB-2 while the MK-4830 analogue bound LILRB2 but not LILRB1 (FIG. 3, bottom panels).

[0179] In conclusion, the data demonstrate that antibodies 28425.30976 and 28425.34436 bound LILRB1 and LILRB2 in the picomolar range and both showed a superior binding to LILRB1 and LILRB2 as compared to the comparator NGM707 analogue.Table 8: LIRB1 / 2 Binding Activity (Mean ECso ±SD from Individual Experiments)n = Number of individual experiments, NB=No bindingExample 6: Binding of anti-LILRB antibodies to primary human immune cells

[0180] CD8+T cells were isolated using the EasySep™ human CD8+T cells isolation kit (STEMCELL Technologies) according to manufacturer instructions, while primary human PBMC from two donors were thawed from -80°C in warm RPMI1640 medium with 10% fetal bovine serum (FBS) and filtered in a 50 pm strainer. After spinning the cells down, the medium was removed and PBS containing 1 pL per million cells of Live / Dead Fixable Aqua (Invitrogen) was added to the cells for 15 minutes on ice, protected from light. Cells were then washed and incubated with TruStain FcX™ (Biolegend) Fc blocker and 2% human serum (Sigma- Aldrich) for 10 minutes on ice protected from light. In the meantime, anti- LILRB 1 / 2 antibodies 28425.30976 and 28425.34436 and reference analogue antibodies were labelled using a Zenon™ kit (Invitrogen) with AF647 and the antibody mix (Invitrogen) used to identify different cell populations was prepared (CD3-AF488, CD14-PE, CD20-BV421,CD 19 APC-Cy7). After a washing step, the antibody mix and labelled anti -LILRB 1 / 2 antibodies were added to the human PBMC and incubated for 30 minutes in ice, protected from light. After a further washing step, cells were filtered once more and acquired using a Symphony™ A3 instrument (BD Biosciences). Compensation was performed incubating an appropriate amount of antibodies with Abe™ compensating beads (Thermo), while Arc™ beads (Thermo) were used for Live / Dead Fixable Aqua. Antibodies were serially diluted from 200 nM to 50 pM generating an 8-point curve. Data were elaborated using FlowJo software, measuring the MFI of the AF647 signal and calculating the percentage of AF647 positive cells for CD20+B cells and CD14+monocytes.

[0181] In a separate experiment, binding of anti-LILRBl / 2 antibodies 28425.30976 and28425.34436 and reference analogue antibodies to CD56+NK cells was evaluated following the above procedure.

[0182] In a third experiment, binding of anti -LILRB 1 / 2 antibodies 28425.30976 and28425.34436 and reference analogue antibodies to isolated CD8+cells was evaluated by directly staining the cells with Zenon™ kit labelled 28425.30976, 28425.34436 and reference analogue antibodies. After a washing step, cells were filtered once more and acquired using a Symphony™ A3 instrument (BD Biosciences).

[0183] Binding of the cross-reactive anti -LILRB 1 / 2 antibodies 28425.30976 and28425.34436 to CD8+T cells, CD20+B-cells, CD56+NK cells and CD14+monocytes was investigated using either isolated CD8+T cells or PBMCs derived from human donors. As seen in FIG. 4, binding of 28425.30976 and 28425.34436 to all investigated immune cell subsets was confirmed. Moreover, 28425.30976 and 28425.34436 bound with superior potency to the different immune cell subsets compared to comparator analogues (Table 9). Notably, due to background staining of isotype controls, the frequency of binding was assessed for all cell populations at 12.5 nM antibody concentration (indicated with dotted line in FIG. 4) and summarized in Table 9.Table 9: Frequency and ECso Values for Binding of Anti-LILRBl / 2 and Reference Analogue Antibodies to Human CD20+B Cells, CD14+Monocytes, CD56+NK Cells, and CD8+Isolated T CellsCD8+ T cells CD20+ B cellsCD14+ Monocytes CD56+ NK cellsfreq. : frequencyExample 7: Binding of anti-LILRB antibodies to CHO-S cells transfected with cynomolgus, rhesus or marmoset LILRB1 receptors

[0184] Hamster CHO-S cells expressing rhesus (Macaca mulatto) LILRB1, LILRA1, LILRA2, or LILRA3 or marmoset (Callithrix jacchus) LILRB 1 or LILRA receptors have been encoded using green (Cat. 90355, Sartorius) and violet (Cat. 97056, Sartorius) encoder dyes at different intensities to allow detection of each population seeded in the same well. The anti-LILRB 1 / 2 antibodies 28425.30976 and 28425.34436 and reference analogue antibodies were incubated with hamster CHO-S cells transiently expressing rhesus LILRB 1, LILRA 1, LILRA2, or LILRA3 or marmoset LILRB 1 or LILRA receptors for 30 minutes at 4°C. The cells were washed twice and subsequently incubated for an additional 20 minutes with AF647-conjugated secondary anti-human IgG (H+L) antibody. After a washing step, the antibody binding was detected using the high-throughput flow cytometer iQue® Screener PLUS (Sartorius) measuring the GeoMean of AF647 signal in each well. The antibodies were serially diluted from 200 nM to 3 pM generating a 12-point curve and every concentration was analyzed in triplicate.

[0185] In a separate experiment, binding of anti-LILRBl / 2 antibodies 28425.30976 and 28425.34436 and reference analogue antibodies to cynomolgus (Macaca fascicularis) LILRB 1, LILRA2 and LILRA3 transiently expressed on CHO-S cells was analyzed. Two versions of cynomolgus LILRB 1 protein have been tested: a version derived from the literature (Storm et al., Front. Immunol., (2021) 12:716289), and another version derived from a United States patent publication (US 2021 / 0355211 Al, SEQ ID NO: 166). The experiment was conducted as described above. The antibody binding was detected using the high-throughput flow cytometer iQue3® (Sartorius) measuring the GeoMean of AF647 signal in each well. Antibodies were serially diluted from 200 nM to 3 pM generating a 12- point curve and every concentration was analyzed in duplicate. Efficacy and ECso values were calculated using GraphPad Prism 10 software.

[0186] Binding of the cross-reactive anti-LILRB 1 / 2 antibodies 28425.30976 and 28425.34436 to different species was assessed by investigating the binding of the antibodies to CHO-S cells transfected with rhesus, marmoset, and cynomolgus LILRB 1, LILRA,LILRA1, LILRA2, LILRA3. As seen in FIG. 5 and FIG. 6, 28425.30976 and 28425.34436 did not bind to rhesus, marmoset or cynomolgus LILRB 1. By contrast, the NGM707 analogue bound to rhesus and marmoset LILRB 1. In addition, binding of NGM707 and BND-22 analogues to cynomolgus LILRB 1 was confirmed.

[0187] Regarding the LILRA family members, binding of 28425.30976 and 28425.34436 antibodies was confirmed to LILRA1 (rhesus), LILRA2 (rhesus and cynomolgus) and LILRA3 (rhesus and cynomolgus) as well as LILRA (marmoset).

[0188] The efficacy and ECso values for binding of 28425.30976, 2845.34436 and reference analogue antibodies to CHO-S cells transfected with cynomolgus LILRB 1, LILRA2, and LILRA3, rhesus LILRB 1, LILRA 1, LILRA2, and LILRA3, and marmoset LILRB 1 and LILRA are shown in Table 10.Table 10: Efficacy and ECso Values for Binding of Anti-LILRBl / 2 and Reference Analogue Antibodies to CHO-S Cells Transfected with Cynomolgus, Rhesus, and Marmoset LILRB and LILRA Family MembersRhesus LILRB1 ecdRhesus LILRA1 ecdRhesus LILRA2 ecdRhesus LILRA3 FL Marmoset LILRB1 ecdMarmoset LILRA ecdCynomolgusLILRB1 ecd (Paper)CynomolgusLILRB1 ecd (Patent) Cynomolgus LILRA2 ecd Cynomolgus LILRA3 ecdData are shown as means ± SD of triplicates for rhesus and marmoset receptors, while data ± SEM of duplicates are shown for cynomolgus proteins.Eff: EfficacyExample 8: Binding of anti-LILRBl antibodies to CHO-S cells transfected with six polymorphic variants of human LILRB1

[0189] Hamster CHO-S cells expressing extracellular domains (ECD) of wild-type (WT) LILRB 1 and six LILRBl polymorphic variants (L45P, I119T, S132I, L45P / I119T, L45P / I119T / S132I, and A70P / L45P / I119T / S132I) have been encoded using green (Cat.90355, Sartorius) and violet (Cat. 97056, Sartorius) encoder dyes at different intensities to allow detection of each population seeded in the same well. The anti -LILRB 1 / 2 antibodies 28425.30976 and 28425.34436 and anti-V5 tag antibodies were incubated with a hamster CHO-S cell line transiently expressing LILRB 1 WT ECD, one of the following polymorphic variant ECDs: L45P, I119T, S132I, L45P / I119T, L45P / I119T / S132I, A70P / L45P / I119T / S132I, or mock control for 30 minutes at 4°C. The cells were washed twice and subsequently incubated for an additional 20 minutes with AF647-conjugated secondary anti-human IgG (H+L) polyclonal antibody (Invitrogen). After a washing step, antibody binding was detected using a high-throughput flow cytometer iQue® Screener PLUS (Sartorius) measuring the GeoMean of AF647 signal in each well. Antibodies were serially diluted from 200 nM to 3 pM generating a 12-point curve. Data were elaborated using GraphPad Prism 10 software.

[0190] Binding of the cross-reactive LILRB1 / 2 antibodies 28425.30976 and 28425.34436 to CHO-S cells transiently expressing LILRB 1 (WT or one of the six variants) was assessed to verify that the antibodies described herein bind to polymorphic variants of LILRB 1. As seen in FIG. 7, 28425.30976 and 28425.34436 bound to all six LILRB1 polymorphic variants in comparison to mock-transfected control. Moreover, antibody binding to the polymorphic variants was comparable to the binding of 28425.30976 and 28425.34436 antibodies to wild-type LILRB 1. Importantly, due to differences in expression levels among the different LILRB 1 polymorphic variants as well as LILRB 1 WT constructs, direct comparison of binding was not possible (FIG. 7, V-5 tag expression control).Example 9: Epitope mapping of anti-LILRBl antibodies by mutagenesis and surface plasmon resonance

[0191] Linear epitopes (also termed continuous epitopes) and conformational epitopes (also termed discontinuous epitopes) were characterized by a mutagenesis approach and surface plasmon resonance (SPR). This example illustrates how the LILRB 1 and LILRB2 epitopes recognized by monoclonal antibodies 28425.30976, 28425.34436, the BND-22 analogue, and the NGM707 analogue are distributed on the LILRB 1 and LILRB2 extracellular domain (ECD).

[0192] LILRB 1 and LILRB2 a transmembrane protein belonging to the immunoglobulin superfamily. The receptors consist of four extracellular immunoglobulin-like domains (domain 1-4), a transmembrane region, and a cytoplasmic tail. LILRB 1 and LILRB2 interact with MHC class I molecules , through the two N-terminal Ig-like domain 1 and 2. The crystalstructure of LILRB1 / HLA-A2 complex reveals two binding sites on HLA-A2, the a3 domain, interacting with domain 1 of LILRB1, and P2m interacting with LILRB1 domain 2. The LILRB2 / HLA-G structure share some binding features with LILRB1 / HLA-A2, but also exhibits differences in its binding interface, favouring a3 domain recognition compared to the P2m interaction (Benjamin E Willcox et al., Crystal structure of HLA-A2 bound to LIR-1, a host and viral major histocompatibility complex receptor, Nat Immunol 4, 2003 and Mitsunori Shiroishi et al., Structural basis for recognition of the nonclassical MHC molecule HLA-G by the leukocyte Ig-like receptor B2 (LILRB2 / LIR2 / ILT4 / CD85d), PNAS, 2006 and Qihui Wang et al., Structures of the four Ig-like domain LILRB2 and the four-domain LILRB1 and HLA-G 1 complex, Cell Mol Immunol., 2020)

[0193] The protein sequences of human LILRB1, LILRB2 and LILRB3 were downloaded from UniProt (Accession Nos. Q8NHL6, Q8N423 and 075022, respectively) and aligned. To map linear epitopes, Fc fusion proteins of domain 1 and 2 of human LILRB1 ECD, as well as domain 1 of human LILRB2 ECD, were generated having 10 amino acids sequentially exchanged by the corresponding LILRB3 sequence in segments overlapping by 5 amino acids. Conformational epitopes were characterized by alanine-scanning mutagenesis of LILRB1 domains 1 and 2 and LILRB2 domain 1.

[0194] The cDNA coding for human LILRB1 and LILRB2 ECD was synthesized and cloned into a vector containing cytomegalovirus (CMV) promoter and human Ig Fc sequence (residues P101-K330), resulting in fusion of Ig Fc to the C-terminus. Wild type (WT) and mutated human LILRB1 and LILRB2 Fc fusion constructs were generated by standard gene synthesis techniques and proteins were expressed transiently in an Expi293™ expression system. After harvesting, supernatants were tested for binding to anti-LILRBl and LILRB 1 / 2 Fabs by SPR using Carterra LSA. An HC200M (Carterra, Inc.) chip was functionalized by goat anti -human Ig Fc (Southern Biotech) using amine-coupling. The chip was activated by freshly prepared 0.4 M EDC, 0.1 M sulfo-NHS, and 0.1 M MES, pH 5.5 (1 : 1 :1 v / v / v) for 5 min, coupled with 75 pg / mL anti -human Ig Fc in 10 mM sodium acetate, pH 4.5, for 10 min, and excess reactive esters were quenched for 3 min by injection of 1 M ethanolamine, pH 8.5. The instrument was primed in running buffer (PBS pH 7.4, 0.01% Tween-20, 0.5 mg / ml BSA). After priming and washing, LILRB1 or LILRB2 fusion proteins in culture supernatants were captured onto individual spots of the chip for 12 minutes as duplicates. Fab analytes were each prepared in running buffer. Kinetic analysis was performed by applying kinetic titration series of monomeric Fabs at increasing concentrations. Fab association was performed for 5 minutes, and antigen dissociation wasrecorded for 5 minutes. After each cycle of Fab injections, the surface was regenerated by 0.45% H3PO4 for 2x20 s and washed for 5 min in running buffer. Binding responses were processed and analyzed using Carterra’s KIT software tool. Processed data was fitted to a simple Langmuir 1 : 1 binding model for calculation of the on-rate (konor ka), off-rate (koff or ka) and affinity (KD) constants. Mutations generating inactive proteins common for all Fab fragments were deselected. To identify amino acids causing a significant loss of binding, a cutoff of at least a 5-fold decrease in binding affinity compared to wild type human LILRB1 or LILRB2 and / or having a z-score above 3 were used to define the epitopes.

[0195] The linear and conformational epitopes of anti-LILRBl / 2 antibodies 28425.30976 and 28425.34436, the BND-22 analogue, and the NGM707 analogue are shown in Table 11 and FIG. 8.Table 11: Linear and Conformational LILRB1 and LILRB2 Epitope of Antibodies 28425.30976, 28425.34436, NGM707 Analogue, and BND-22 Analogue

[0196] The cross-reactive anti-LILRBl / 2 antibodies 28425.30976 and 28425.34436 share a common epitope at domain 1 of LILRB1. The epitope does not include amino acids situated on the interacting surfaces of the receptor and the ligand HLA-G1, suggesting that the antibodies primarily impede ligand interaction via steric hindrance (FIG. 8). Only the epitope bound by 28425.30976 was characterized for LILRB2, showing a highly conservedepitope to that of the LILRB1 antigen. A key difference is at position 51, where LILRB1 has Pro51 and LILRB2 has Arg51. This substitution can affect the affinity, with 28425.30976 showing a KD of 0.08 nM for LILRB1 and 5.5 nM for LILRB2.

[0197] The NGM707 analogue binds domain 1 of LILRB1, overlapping with key HLA- G1 interaction sites, thereby directly blocking the ligand. Its epitope is similar between LILRB1 and LILRB2 but spans a longer sequence in LILRB2. The epitope of the LILRB1 specific BND-22 analogue is predominantly located at domain 2 of LILRB1. Several amino acids of the epitope are important for the interaction with P2m of HLA-G1 : P2m complex, including W67, A98, Y99, 1100, and V126 (Wang et al., Cell Mol Immunol (2020) 17(9):966-75). BND-22 has been reported to interact with LILRB1 at the hinge between DI and D2, the same region that binds specifically to P2m of HLA-G, which agrees with the identified epitope (Mandel et al. J Immunother. Cancer (2022) 10:e004859).

[0198] In conclusion, 28425.30976 binds a highly conserved epitope between LILRB1 and LILRB2, but sequence and structural differences affect binding affinity. The LILRB1 epitope shared by 28425.30976 and 28425.34436 is different from the LILRB1 epitope of the NGM707 analogue but with an overlap of the linear epitope R36-I50. The LILRB1 epitope is distinct from the epitope of the BND-22 analogue, however with a small overlap of the linear epitope P61-A65.Example 10: Blocking of LILRB1 or LILRB2 binding to HLA-G / B2M or HLA- A2 / B2M-transfected CHO-S cells by anti-LILRB antibodies

[0199] Hamster CHO-S cells expressing HLA-G / B2M, HLA / A2 / B2M or mock control have been encoded using violet (Sartorius) encoder dye at different intensities to allow detection of each population seeded in the same well. The anti-LILRB 1 / 2 antibodies were titrated in 96 well plates starting from 200 nM to 3 pM in a 3 -fold serial dilution and subsequently incubated for 30 minutes at 4°C with recombinant human LILRBl-Fc tagged or human LILRB2-Fc tagged proteins, which were AF647-labelled using a Zenon™ kit according to manufacturer instruction (Cat. 25408, Invitrogen). Then, hamster CHO-S cells, transiently co-transfected with human HLA-G and beta-2 -microglobulin (B2M) or HLA-A2 and B2M or mock control, were added to each well and incubated for further 30 minutes at 4°C. After a washing step, antibody binding was detected using a high-throughput flow cytometer iQue3® (Sartorius) measuring the GeoMean of AF647 signal in each well. A 12- point curve was generated for each antibody and every concentration was analyzed in duplicate.

[0200] The cross-reactive anti-LILRBl / 2 antibodies 28425.30976 and 28425.34436 fully blocked the binding of LILRB1 to both HLA-G / B2M and HLA-A2 / B2M expressed on CHO- S cells (FIG. 9, top left and bottom left; Table 12) compared to isotype control or the LILRB2 specific negative control (MK-4830 analogue). Notably, the blocking capacity of 28425.30976 and 28425.34436 was comparable with the blocking capacity mediated by the NGM707 analogue or BND-22 analogue.

[0201] In addition, antibodies 28425.30976 and 28425.34436 fully blocked the binding of LILRB2 to both HLA-G / B2M and HLA-A2 / B2M expressed on CHO-S (FIG. 9, top right and bottom right; Table 12) compared to isotype control or the LILRB1 specific negative control (BND-22 analogue). Notably, the blocking capacity of 28425.30976 and 28425.34436 was comparable with the blocking capacity mediated by the NGM707 analogue or MK-4830 analogue.Table 12: Efficacy and ICso Values for Blocking of LILRB1 or LILRB2 Binding to HLA-G / B2M or HLA-A2 / B2M-Transiently Transfected CHO-S Cells by anti-LILRB 1 / 2 and Reference Analogue AntibodiesData are shown as mean ± SEM of duplicatesEff.: Efficacy inh.: inhibitionExample 11: Effect of anti-LILRB antibodies on cytolytic activity of NK cells

[0202] To assess if anti-LILRB antibody treatment can enhance NK cell activity, an NK cell cytotoxicity assay was performed using the KHYG-1 NK cell line overexpressing either LILRB1 or LILRB2. Briefly, HLA-G transduced K562 tumor cells were loaded with H2A (77-85) peptide (GenScript) at 200 pM to allow optimal HLA-G expression for 16 hrs at 30 °C. The next day, K562HLA'G+tumor cells were labeled with Calcein AM viability dye(Invitrogen / Life technologies) at 20 pM and co-cultured with either KHYG-1LILRB1or KHYG-1LILRB2NK cells in the presence of anti-LILRB antibodies or antibody control at an E:T ratio of 10: 1 (NK cell: tumor cell). Maximum lysis was induced by treatment of target cells with 1% Triton X-100. NK cell mediated cytotoxicity of tumor cells was determined after 4 hrs of co-culture. The level of tumor cell killing was determined by using the following equation: % tumor cell killing = % lysis of sample - % lysis (spontaneous) / % lysis (maximum)- % lysis (spontaneous).

[0203] As seen in FIG. 10, Panels A and B, treatment with the cross-reactive anti- LILRB1 / 2 antibodies 28425.30976 and 28425.34436 enhanced tumor cell killing compared to isotype control in a dose dependent manner. The herein developed NK cell cytotoxicity assay allowed specific assessment of the contribution of LILRB1 or LILRB2 in NK cell- mediated cytotoxicity as the LILRB2 specific MK-4830 analogue had no effect in the LILRB1 specific assay (FIG. 10, Panel A left) and the LILRB1 specific BND-22 analogue did not enhance NK cell cytotoxicity in the LILRB2 specific assay (FIG. 10, Panel A right). The LILRB1 / 2 cross-reactive NGM707 analogue induced comparable levels of tumor cell killing compared to 28425.30976 and 28425.34436 in both the LILRB1 and LILRB2 specific assay (FIG. 10, Panel B (left and middle); Table 13). Importantly, in the LILRB1 specific assay 28425.30976 and 28425.34436 induced tumor cell killing with superior potency compared to the NGM707 analogue (ECso, Table 13). Moreover, 28425.30976 enhanced tumor cell killing with superior potency as well as efficacy compared to the MK-4830 analogue (FIG. 10, Panel B (right); Table 13).

[0204] In conclusion, these results show that anti-LILRB antibodies can block the interaction with HLA-G expressing tumor cells leading to enhancement of cytolytic NK cell activity.Table 13: Efficacy and ECso Values for Anti-LILRBl / 2 and Reference Analogue Antibodies (NK Cell Cytotoxicity Assays)Example 12: Effect of anti-LILRB antibodies on macrophage phagocytosis

[0205] To evaluate if anti-LILRB antibody treatment can potentiate anti-CD47-mediated antibody-dependent cellular phagocytosis (ADCP) a macrophage phagocytosis assay was performed. Briefly, CD14+monocytes were isolated from the peripheral blood compartment of healthy donors and cultured in the presence of M-CSF (50 ng / mL; Peprotech) to differentiate the cells towards the macrophage lineage for 6 or 7 days, in vitro. Differentiated macrophages were harvested and co-cultured with HLA-G-transduced and fluorescently labelled (1 pg pHodo / mL; Essen Bioscience) A375 cells at an E:T of 1 :2 in the presence of anti-CD47 (67 nM, FortySeven analogue) alone or in combination with anti-LILRB antibodies (133 nM). Phagocytosis of target cells by differentiated macrophages was assessed by measuring uptake of tumor cells analyzed over a period of 24 hrs using IncuCyte® technology.

[0206] As shown in FIG. 11, treatment with the cross-reactive antibody 28425.30976 and the LILRB 1 specific BND-22 analogue potentiated antibody-dependent macrophage phagocytosis compared to anti-CD47 treatment alone (dotted line). By contrast, treatment with 28188.30971, an anti-LILRB2 specific antibody, had no effect.

[0207] These findings show that anti-LILRB 1 and anti-LILRB 1 / 2 antibodies can enhance macrophage phagocytosis by blocking the interaction of LILRB 1 expressed by macrophages and HLA-G expressed by tumor cells subsequently leading to enhanced macrophage activation.Example 13: Effect of anti-LILRB antibody treatment on the activation of human leukocytes (PBMCs) following exposure to LPS

[0208] To assess whether anti-LILRB antibodies can modulate LPS-mediated stimulation, a PBMC / LPS assay was performed. Briefly, human PBMCs were isolated from healthy donors and l >< 106cells were seeded in culture medium (RPMI 1640 + 10% FBS + 1% p / s) into 96 round bottom plates and treated with selected anti-LILRB antibodies or isotype control at 167 nM. The next day, the TLR2 / 4 agonist LPS was added at 30 ng / mL to the PBMC culture. Cell culture supernatants were harvested 48 hrs post-LPS exposure and subsequently the levels of released TNFa, GM-CSF and IL-10 cytokines were quantified using Meso Scale Discovery technologies.

[0209] As shown in FIG. 12A, treatment with the cross-reactive anti-LILRB 1 / 2 antibodies 28425.30976 and 28425.34436 induced the secretion of TNFa and GM-CSF anddecreased the secretion of IL-10 compared to isotype control in n>10 PBMC donors. Moreover, treatment efficacy was comparable to MK-4830 analogue as well as NGM707 analogue. FIG. 12B highlights the effect of 28425.30976 on individual PBMC donors compared to isotype control. Importantly, treatment with anti-LILRBl specific antibodies had no effects (data not shown). These findings suggest that the expression of LILRB2 in the PBMC / LPS culture can modulate the secretion of pro- as well as anti-inflammatory cytokines that can be reversed by blocking the LILRB2 / MHC I axis.Example 14: Effect of anti-LILRB antibody treatment on anti-CD3-mediated stimulation of human leukocytes (PBMCs)

[0210] To assess whether anti-LILRB antibody treatment can modulate the activation of anti-CD3 -mediated stimulation, a PBMC / anti-CD3 assay was performed. Briefly, human PBMCs were isolated from healthy donors and 1 x 106cells were seeded in culture medium (RPMI 1640 + 10% FBS + 1% p / s) into 96 round bottom plates and treated with selected anti-LILRB antibodies or isotype control at 167 nM. The following day, the PBMC received anti-CD3 antibody treatment at 10 ng / mL. After four days, cell culture supernatants were harvested and the secretion of TNFa, IFNy, GM-CSF and IL-6 were quantified using Meso Scale Discovery technologies.

[0211] As depicted in FIG. 13A, treatment with the cross-reactive anti-LILRB 1 / 2 antibodies 28425.30976 and 28425.34436 induced elevated secretion of TNFa, IFNy, and GM-CSF whilst limiting the secretion of IL-6 in comparison to isotype control (n>5 PBMC donors). Moreover, treatment efficacies appeared to be comparable to that of MK-4830 and NGM707 analogues. FIG. 13B highlights the effect of 28425.30976 in individual PBMC donors compared to isotype control. Importantly, treatment with anti-LILRBl specific antibodies had no impact on the release of the assessed cytokines (data not shown).

[0212] These findings provide evidence that obstructing the LILRB2 receptor-MHC-I signaling axis can result in enhanced immune function and secretion of inflammatory cytokines (both pro- and anti-) initiated by anti-CD3 stimulation and executed by the various LILRB2 expressing immune cells that populate the PBMC pool.Example 15: Effect of anti-LILRB treatment on modulating M2-macrophage driven CD4 MLR responses

[0213] To assess the effect of anti-LILRB antibody treatment in modulating CD4+T cell responses, isolated lymphocytes were co-cultured with allogeneic CD14+monocyte derivedM2 polarized macrophages. Briefly, CD14+monocytes were isolated from the peripheral blood compartment of healthy donors and cultured, in vitro, in the presence of M-CSF (50 ng / mL; Peprotech) to differentiate the cells towards the macrophage lineage. On day 6 of in vitro culture the cells were exposed to IL-4 (25 ng / mL: Peprotech) to polarize the macrophages towards an anti-inflammatory M2 profile. Differentiated cells were harvested on day 7 of in vitro cell culture, to determine the viability and cell count. Subsequently, the cells were seeded at 0.2 x 106 / mL in culture medium (T-Otimizer™; Life Technologies supplemented with 0.1% penicillin and streptomycin and 2 mM of glutamine) and treated with selected anti-LILRB mAbs, mAb control and anti-PDl (KEYTRUDA®) as positive control at 167 nM. The next day, cells were exposed to the TLR2 / 4 agonist LPS at 30 ng / mL to induce maturation of the cells before initiating MLR responses. Post LPS maturation, supernatants were collected whilst CD4+T cells were isolated from the peripheral blood compartment of independent donors and added to the M2 macrophage culture at a ratio of 1 : 10 (macrophage: T cell) to initiate the MLR. Culture supernatants were harvested at day 5 of the MLR whereas at day 7, the cells were stained for the cell surface expression of CD25, HLA-DR and Ki67 using flow cytometry.

[0214] To assess the effect of anti-LILRB 1 / 2 treatment on MLR responses, both the levels of pro-inflammatory cytokines TNFa or IFNy were determined, and the frequencies of proliferation and activation of responder CD4+T cells. As depicted in FIG. 14, treatment with the cross-reactive antibody 28425.30976 enhanced the secretion of TNFa (FIG. 14, Panel A) and fFNy (FIG. 14, Panel B) in comparison to no antibody treatment or isotype control. Importantly, the levels of released pro-inflammatory cytokines were comparable to those observed with either the MK-4830 analogue or the NGM707 analogue. In contrast, treatment with anti-LILRB 1 specific antibodies showed no effect (data not shown).

[0215] In addition, maturation of the M2 macrophages treated with 28425.30976 or competitor analogue molecules amplified the release of TNFa in comparison to isotype control, indicating a shift of M2 polarized macrophages towards a more pro-inflammatory functional phenotype (FIG. 14, Panel C).

[0216] MLR-induced proliferation and activation of CD4+T-cells were assessed following treatment of LPS-matured M2 macrophages with 28425.30976 or isotype control. As shown in FIG. 14, Panel D (left), upregulation of intracellular Ki67 expression levels was observed in CD4+T cells in 28425.30976-treated groups in comparison to isotype control, indicative of enhanced lymphocyte proliferation responses. The same is observed with CD25(FIG. 14, Panel D, middle) and HLA-DR (FIG. 14, Panel D, right) expression levels, antigens that indicate lymphocyte activation.

[0217] Overall, these findings provide evidence that treatment with anti-LILRB2 and anti -LILRB 1 / 2 antibodies effectively block the interaction of LILRB2 and MHC I molecules on neighboring M2 -polarized macrophages and effectively disrupt macrophage-mediated suppression of allogeneic T cell effector functions during an MLR.Example 16: PK properties of anti-LILRB antibodies in the human FcRn transgenic mouse and PK / PD modelling data

[0218] To generate PK data for antibody 28425.30976, female hFcRn transgenic mice (n=30, Biocytogen, China) received different doses of the antibody (0.1 mg / kg, 1 mg / kg, or 10 mg / kg) via intravenous (IV) or intraperitoneal (IP) routes. Plasma samples were collected at specific time points post-dose and analyzed using an automated affinity flow-through assay on the GyroLab™ xP platform. Biotinylated LILRB 1 (Aero Bioscience) was used to capture antibody 28425.30976 in a calibrator and samples and bound antibody 28425.30976 were detected using Alexa-fluor labeled polyclonal goat anti-human IgG (Jackson Immuno Research).

[0219] The initial antibody / drug level was at an expected level for the different doses. Three mice of the 10 mg / kg IP group had unexpectedly low exposure and were excluded from the non-compartmental analysis (NCA). This low exposure was suspected to be related to incorrect administration, as the elimination rate seemed to be equal in all the IP mice, despite the difference in C max-

[0220] No animals had a PK profile indicating anti-drug antibodies (ADA), and ADA therefore was not assessed.

[0221] The elimination rate seemed equal between the groups. There was an equal halflife between the dose groups (182h, 188h, 168h and 164h) and linearity between the doses (FIG. 15)

[0222] PK / PD modeling and simulations were executed using the software Monolix and Simulx. Data from the humanized FcRn mice study were used to generate a PK model for antibody 28425.30976. This model allowed for simulation of the PK profile of antibody 28425.30976 in a clinical setting. A PK model and a PK / PD model for NGM707 were generated using published PK data and receptor occupancy data from NGMBio (Naing et al., “First-in-Human Study of NGM707, an ILT2 / ILT4 Dual Antagonist Antibody in Advanced or Metastatic Solid Tumors: Preliminary Monotherapy Dose Escalation Data (#174P) ”Poster presented at: 2022 ESMO 1-0 Annual Congress; December 7-9, 2022; Geneva, Switzerland).

[0223] A correction factor was used to calculate the ECso of 28425.30976 based on the difference between the published clinical ECso of NGM707_and the internally generated head-to-head ELISA ECso values.

[0224] For affinity data for 28425.30976 and the NGM707 analogue, head-to-head comparisons between the two antibodies were performed using ELISA and SPR assays.

[0225] The data from the humanized FcRn mice study was used to generate a two- compartment pharmacokinetic model with linear elimination kinetics for antibody 28425.30976. This model was scaled to human and allowed us to simulate the PK profile of antibody 28425.30976 in a clinical setting. The linear part of the PK of NGM707 was described using a two-compartment PK model and the PK / PD of NGM707 was described using a direct sigmoid-Emax response model.

[0226] The PK / PD of antibody 28425.30976 was predicted based on the PK / PD of NGM707 and the correction factor (FIG. 16). The PK simulations show full receptor occupancy at doses of 200mg at Q3W and Q4W for 28425.30976 (FIG. 17).

[0227] In conclusion, antibody 28425.30976 showed favorable PK properties in FcRn mice which, when used in a PK / PD model for clinical setting simulations, supporting a Q4W or longer dosing posology.Table 14: Antibody Sequence Summarynt: nucleotide aa: amino acid

Claims

CLAIMS1. An antibody that specifically binds to human LILRB1 and human LILRB2 (“anti- LILRB1 / 2 antibody”), or an antigen-binding portion thereof, wherein the antibody binds to the same epitope of human LILRB1 and / or human LILRB2 as an antibody comprising: a) a heavy chain (HC) comprising the amino acid sequences of SEQ ID NOs: 3 and 61 and a light chain (LC) comprising the amino acid sequences of SEQ ID NOs: 4 and 62; b) an HC comprising the amino acid sequences of SEQ ID NOs: 13 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 14 and 62; c) an HC comprising the amino acid sequences of SEQ ID NOs: 23 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 24 and 62; d) an HC comprising the amino acid sequences of SEQ ID NOs: 33 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 34 and 62; or e) an HC comprising the amino acid sequences of SEQ ID NOs: 43 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 44 and 62.

2. The anti -LILRB 1 / 2 antibody or antigen-binding portion of claim 1, wherein a) the heavy chain of said anti -LILRB 1 / 2 antibody comprises: i) heavy chain complementarity determining regions (H-CDR)-l-3 comprising the amino acid sequences of SEQ ID NOs: 5-7, respectively; ii) a heavy chain variable domain (VH) comprising an amino acid sequence at least 90% identical to the amino acid sequence of SEQ ID NO: 3; iii) a VH comprising the amino acid sequence of SEQ ID NO: 3; or iv) a heavy chain (HC) comprising the amino acid sequences of SEQ ID NOs: 3 and 61; and b) the light chain of said anti -LILRB 1 / 2 antibody comprises: i) light chain complementarity determining regions (L-CDR)-l-3 comprising the amino acid sequences of SEQ ID NOs: 8-10, respectively; ii) a light chain variable domain (VL) comprising an amino acid sequenceat least 90% identical to the amino acid sequence of SEQ ID NO: 4; iii) a VL comprising the amino acid sequence of SEQ ID NO: 4; or iv) a light chain (LC) comprising the amino acid sequences of SEQ ID NOs: 4 and 62.

3. The anti -LILRB 1 / 2 antibody or antigen-binding portion of claim 1, wherein a) the heavy chain of said anti -LILRB 1 / 2 antibody comprises: i) heavy chain complementarity determining regions (H-CDR)-l-3 comprising the amino acid sequences of SEQ ID NOs: 15-17, respectively; ii) a heavy chain variable domain (VH) comprising an amino acid sequence at least 90% identical to the amino acid sequence of SEQ ID NO: 13; iii) a VH comprising the amino acid sequence of SEQ ID NO: 13; or iv) a heavy chain (HC) comprising the amino acid sequences of SEQ ID NOs: 13 and 61; and b) the light chain of said anti -LILRB 1 / 2 antibody comprises: i) light chain complementarity determining regions (L-CDR)-l-3 comprising the amino acid sequences of SEQ ID NOs: 18-20, respectively; ii) a light chain variable domain (VL) comprising an amino acid sequence at least 90% identical to the amino acid sequence of SEQ ID NO: 14; iii) a VL comprising the amino acid sequence of SEQ ID NO: 14; or iv) a light chain (LC) comprising the amino acid sequences of SEQ ID NOs: 14 and 62.

4. The anti -LILRB 1 / 2 antibody or antigen-binding portion of claim 1, wherein a) the heavy chain of said anti -LILRB 1 / 2 antibody comprises: i) heavy chain complementarity determining regions (H-CDR)-l-3 comprising the amino acid sequences of SEQ ID NOs: 25-27, respectively; ii) a heavy chain variable domain (VH) comprising an amino acid sequence at least 90% identical to the amino acid sequence of SEQ ID NO: 23;iii) a VH comprising the amino acid sequence of SEQ ID NO: 23; or iv) a heavy chain (HC) comprising the amino acid sequences of SEQ ID NOs: 23 and 61; and b) the light chain of said anti -LILRB 1 / 2 antibody comprises: i) light chain complementarity determining regions (L-CDR)-l-3 comprising the amino acid sequences of SEQ ID NOs: 28-30, respectively; ii) a light chain variable domain (VL) comprising an amino acid sequence at least 90% identical to the amino acid sequence of SEQ ID NO: 24; iii) a VL comprising the amino acid sequence of SEQ ID NO: 24; or iv) a light chain (LC) comprising the amino acid sequences of SEQ ID NOs: 24 and 62.

5. The anti -LILRB 1 / 2 antibody or antigen-binding portion of claim 1, wherein a) the heavy chain of said anti -LILRB 1 / 2 antibody comprises: i) heavy chain complementarity determining regions (H-CDR)-l-3 comprising the amino acid sequences of SEQ ID NOs: 35-37, respectively; ii) a heavy chain variable domain (VH) comprising an amino acid sequence at least 90% identical to the amino acid sequence of SEQ ID NO: 33; iii) a VH comprising the amino acid sequence of SEQ ID NO: 33; or iv) a heavy chain (HC) comprising the amino acid sequences of SEQ ID NOs: 33 and 61; and b) the light chain of said anti -LILRB 1 / 2 antibody comprises: i) light chain complementarity determining regions (L-CDR)-l-3 comprising the amino acid sequences of SEQ ID NOs: 38-40, respectively; ii) a light chain variable domain (VL) comprising an amino acid sequence at least 90% identical to the amino acid sequence of SEQ ID NO: 34; iii) a VL comprising the amino acid sequence of SEQ ID NO: 34; or iv) a light chain (LC) comprising the amino acid sequences of SEQ ID NOs: 34 and 62.

6. The anti -LILRB 1 / 2 antibody or antigen-binding portion of claim 1, wherein a) the heavy chain of said anti -LILRB 1 / 2 antibody comprises: i) heavy chain complementarity determining regions (H-CDR)-l-3 comprising the amino acid sequences of SEQ ID NOs: 45-47, respectively; ii) a heavy chain variable domain (VH) comprising an amino acid sequence at least 90% identical to the amino acid sequence of SEQ ID NO: 43; iii) a VH comprising the amino acid sequence of SEQ ID NO: 43; or iv) a heavy chain (HC) comprising the amino acid sequences of SEQ ID NOs: 43 and 61; and b) the light chain of said anti -LILRB 1 / 2 antibody comprises: i) light chain complementarity determining regions (L-CDR)-l-3 comprising the amino acid sequences of SEQ ID NOs: 48-50, respectively; ii) a light chain variable domain (VL) comprising an amino acid sequence at least 90% identical to the amino acid sequence of SEQ ID NO: 44; iii) a VL comprising the amino acid sequence of SEQ ID NO: 44; or iv) a light chain (LC) comprising the amino acid sequences of SEQ ID NOs: 44 and 62.

7. An anti -LILRB 1 / 2 antibody or an antigen-binding portion thereof, wherein said antibody comprises the H-CDR1-3 and L-CDR1-3 amino acid sequences of: a) SEQ ID NOs: 5-10, respectively; b) SEQ ID NOs: 15-20, respectively; c) SEQ ID NOs: 25-30, respectively; d) SEQ ID NOs: 35-40, respectively; or e) SEQ ID NOs: 45-50, respectively.

8. The anti -LILRB 1 / 2 antibody or antigen-binding portion of claim 7, wherein said antibody comprises a heavy chain variable domain amino acid sequence and a light chain variable domain amino acid sequence that are at least 90% identical to the amino acid sequences of: a) SEQ ID NOs: 3 and 4, respectively;b) SEQ ID NOs: 13 and 14, respectively; c) SEQ ID NOs: 23 and 24, respectively; d) SEQ ID NOs: 33 and 34, respectively; or e) SEQ ID NOs: 43 and 44, respectively.

9. The anti -LILRB 1 / 2 antibody or antigen-binding portion of claim 7, wherein said antibody comprises a heavy chain variable domain and a light chain variable domain comprising the amino acid sequences of: a) SEQ ID NOs: 3 and 4, respectively; b) SEQ ID NOs: 13 and 14, respectively; c) SEQ ID NOs: 23 and 24, respectively; d) SEQ ID NOs: 33 and 34, respectively; or e) SEQ ID NOs: 43 and 44, respectively.

10. The anti -LILRB 1 / 2 antibody of any one of claims 1-9, wherein the antibody is an IgG.

11. The anti -LILRB 1 / 2 antibody of claim 10, wherein the antibody is an IgGi.

12. The anti -LILRB 1 / 2 antibody of any one of claims 1-11, wherein the antibody comprises at least one mutation in the Fc region.

13. The anti -LILRB 1 / 2 antibody of claim 12, wherein the antibody is of isotype subclass IgGi and one or both of the amino acid residues at positions 234 and 235 are mutated from Leu to Ala.

14. An anti -LILRB 1 / 2 antib ody that compri se s : a) a heavy chain (HC) comprising the amino acid sequences of SEQ ID NOs: 3 and 61 and a light chain (LC) comprising the amino acid sequences of SEQ ID NOs: 4 and 62; b) an HC comprising the amino acid sequences of SEQ ID NOs: 13 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 14 and 62; c) an HC comprising the amino acid sequences of SEQ ID NOs: 23 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 24 and 62;d) an HC comprising the amino acid sequences of SEQ ID NOs: 33 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 34 and 62; or e) an HC comprising the amino acid sequences of SEQ ID NOs: 43 and 61 and an LC comprising the amino acid sequences of SEQ ID NOs: 44 and 62.

15. An anti -LILRB 1 / 2 antibody or an antigen-binding portion thereof that binds to an epitope on human LILRB 1 comprising amino acid residues G19, P21, W46, R49, 150, P51, F60, P63, S64, and H69.

16. An anti -LILRB 1 / 2 antibody or an antigen-binding portion thereof that binds to an epitope on human LILRB 1 comprising amino acid residues El 1-R25, and optionally further comprising amino acid residues R36-I65 or K41-I65.

17. An anti -LILRB 1 / 2 antibody or an antigen-binding portion thereof that binds to an epitope on human LILRB2 comprising amino acid residues G19, P21, W46, R49, 162, P63, and H69.

18. An anti -LILRB 1 / 2 antibody or an antigen-binding portion thereof that binds to an epitope on human LILRB2 comprising amino acid residues El 1-P20 and optionally further comprising amino acid residues K41-165.

19. An anti -LILRB 1 / 2 antibody or an antigen-binding portion thereof that binds to an epitope on human LILRB 1 comprising amino acid residues G19, P21, W46, R49, 150, P51, F60, P63, S64, and H69 and that binds to an epitope on human LILRB2 comprising amino acid residues G19, P21, W46, R49, 162, P63, and H69.

20. The anti -LILRB 1 / 2 antibody or antigen-binding portion of any one of claims 1-19, wherein the antibody or antigen-binding portion has at least one property selected from: a) binds to human LILRB 1 with a KD of 0.1 nM or less as measured by surface plasmon resonance (SPR); b) binds to human LILRB2 with a KD of 10 nM or less as measured by surface plasmon resonance (SPR); c) binds to human LILRB 1 with an ECso of 0.1 nM or less as measured byELISA; d) binds to human LILRB2 with an EC50 of 0.2 nM or less as measured by ELISA; e) binds to human LILRA1 with a KD of 1 nM or less as measured by surface plasmon resonance (SPR); f) binds to human LILRA2 with a KD of 20 nM or less as measured by surface plasmon resonance (SPR); g) binds to human LILRA3 with a KD of 1.1 nM or less as measured by surface plasmon resonance (SPR); h) does not bind to human LILRB3, LILRB4, LILRB5, LILRA4, LILRA5, and LILRA6; i) does not bind to rhesus, marmoset, or cynomolgus LILRB 1 ; j) binds to rhesus LILRA1, LILRA2, and LILRA3, cynomolgus LILRA2 and LILRA3, and marmoset LILRA; k) binds to LILRB 1 polymorphic variants L45P, Il 19T, S132I, L45P / I119T, L45P / I119T / S132I, and A70P / L45P / I119T / S132I; l) binds to domain 1 of human LILRB 1 ; m) binds to a different epitope of human LILRB 1 than anti -LILRB 1 / 2 antibody NGM707 or anti -LILRB 1 antibody BND-22; n) binds to CD20+B cells, CD14+monocytes, CD56+NK cells, and CD8+T cells; o) blocks LILRB 1 binding to HLA-G / B2M and HLA-A2 / B2M; p) blocks LILRB2 binding to HLA-G / B2M and HLA-A2 / B2M; q) enhances cytolytic NK cell activity; r) induces secretion of TNFa and GM-CSF, and / or reduces secretion of IL-10, in a PBMC / LPS assay; s) induces secretion of TNFa, IFNy, and GM-CSF, and / or limits secretion of IL-6, in a PBMC / anti-CD3 assay; t) enhances macrophage phagocytosis of HLA-G-expressing cells; u) increases secretion of TNFa and IFNY in amixed lymphocyte reaction (MLR) assay; v) increases proliferation and activation of CD4+ T cells in an MLR assay; and w) demonstrates full LILRB 1 and LILRB2 receptor occupancy at Q3W and Q4W in a two-compartment pharmacokinetic model with linear elimination kinetics.

21. The anti -LILRB 1 / 2 antibody or antigen-binding portion of claim 20, wherein the antibody or antigen-binding portion has all of said properties.

22. A pharmaceutical composition comprising the anti-LILRBl / 2 antibody or antigenbinding portion of any one of claims 1-21 and a pharmaceutically acceptable excipient.

23. The pharmaceutical composition of claim 22, further comprising an immunostimulatory agent, a vaccine, a chemotherapeutic agent, an anti -neoplastic agent, an anti -angiogenic agent, or a tyrosine kinase inhibitor.

24. Isolated nucleic acid molecule(s) comprising a nucleotide sequence that encodes the heavy chain, or a nucleotide sequence that encodes the light chain, or both, of the anti- LILRB1 / 2 antibody or antigen-binding portion of any one of claims 1-21.

25. The isolated nucleic acid molecule(s) of claim 24, wherein said nucleic acid molecule(s) comprise the nucleotide sequence of any one of SEQ ID NOs: 1, 2, 11, 12, 21, 22, 31, 32, 41, and 42.

26. Vector(s) comprising the isolated nucleic acid molecule(s) of claim 24 or 25, wherein said vector(s) further comprise an expression control sequence.

27. A host cell comprising a nucleotide sequence that encodes the heavy chain, and a nucleotide sequence that encodes the light chain, of the anti -LILRB 1 / 2 antibody or antigen-binding portion of any one of claims 1-21.

28. A method for producing an anti -LILRB 1 / 2 antibody or an antigen-binding portion thereof, comprising providing a host cell of claim 27, culturing said host cell under conditions suitable for expression of the antibody or antigen-binding portion, and isolating the resulting antibody or antigen-binding portion.

29. A bi-specific binding molecule comprising the antigen-binding domain of an anti- LILRB1 / 2 antibody of any one of claims 1-21 and the antigen-binding domain ofanother, distinct antibody.

30. A method of using the anti -LILRB 1 / 2 antibody or antigen-binding portion of any one of claims 1-21 in a diagnostic process, comprising contacting a sample from a patient with said antibody or antigen-binding portion, and detecting and / or measuring the level of LILRB 1 and / or LILRB2.

31. A method for enhancing immune activity in a patient in need thereof, comprising administering to said patient a therapeutically effective amount of the anti -LILRB 1 / 2 antibody or antigen-binding portion of any one of claims 1-21, the pharmaceutical composition of claim 22 or 23, or the bi-specific binding molecule of claim 29.

32. A method for treating cancer in a patient, comprising administering to said patient a therapeutically effective amount of the anti -LILRB 1 / 2 antibody or antigen-binding portion of any one of claims 1-21, the pharmaceutical composition of claim 22 or 23, or the bi-specific binding molecule of claim 29.

33. The method of claim 32, wherein the cancer is in a tissue selected from the group consisting of skin, lung, intestine, colon, ovary, brain, prostate, kidney, soft tissues, the hematopoietic system, head and neck, liver, bone, bladder, breast, stomach, uterus, cervix, and pancreas.

34. The method of claim 32, wherein the cancer is selected from ovarian cancer, cutaneous squamous cell carcinoma, esophageal cancer, breast, head and neck squamous cell carcinoma, non-small cell lung cancer, sarcoma, biliary tract cancer, and gallbladder cancer.

35. A method for treating an immune disorder in a patient in need thereof, comprising administering to said patient a therapeutically effective amount of the anti -LILRB 1 / 2 antibody or antigen-binding portion of any one of claims 1-21, the pharmaceutical composition of claim 22 or 23, or the bi-specific binding molecule of claim 29.

36. The method of any one of claims 31-35, further comprising administering to the patient an immunostimulatory agent, a vaccine, a chemotherapeutic agent, an anti-neoplastic agent, an anti -angiogenic agent, a tyrosine kinase inhibitor, or radiation therapy.

37. Use of the anti -LILRB 1 / 2 antibody or antigen-binding portion of any one of claims 1- 21, the pharmaceutical composition of claim 22 or 23, or the bi-specific binding molecule of claim 29 for the manufacture of a medicament for: a) enhancing immune activity in a patient; b) treating cancer in a patient; or c) treating an immune disorder in a patient, according to the method of any one of claims 30-36.

38. The anti -LILRB 1 / 2 antibody or antigen-binding portion of any one of claims 1-21, the pharmaceutical composition of claim 22 or 23, or the bi-specific binding molecule of claim 29, for use in: a) enhancing immune activity in a patient; b) treating cancer in a patient; or c) treating an immune disorder in a patient, according to the method of any one of claims 30-36.

39. The method of any one of claims 30-36; the use of claim 37; or the anti -LILRB 1 / 2 antibody or antigen-binding portion, pharmaceutical composition, or bi-specific binding molecule for use of claim 38; wherein the patient is a human.