Methods for reversing immune suppression induced by TREML1

Abstract

Soluble TREML1 is involved in many inflammatory diseases and plays an important role in immunosuppression. Soluble TREML1 can bind to the I-domain of CD11b and induce an immunosuppressive phenotype. Therefore, soluble TREML1 can be an excellent target for treating inflammatory diseases. The present invention relates to antibodies that can reduce soluble TREML1 binding to CD11b+ immune cells and their use to reverse the immunosuppression induced by TREML14. Anti-TREML1 antibodies provide a novel potential treatment for these disease states, such as cancer.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 279,670, filed November 15, 2021, the entirety of which is incorporated herein by reference.

[0002] Sequence Listing Information The sequence listing accompanying this application is provided in XML format in lieu of hard copy and is hereby incorporated by reference herein. The name of the XML file containing the sequence listing is A263-1005PCT.xml. The XML file is 51,147 bytes, was created on October 20, 2022, and has been submitted electronically via the PatentCenter (USA).

[0003] The present disclosure describes antibodies, compositions comprising the antibodies, and methods of using the antibodies to inhibit or reverse immunosuppression. [Background technology]

[0004] TREM-like transcript-1 (TREML1; TLT-1) is a member of the TREM family. TREML1 consists of a single V-set immunoglobulin (Ig) domain, a stalk region containing charged residues, a transmembrane domain, and a cytoplasmic tail. TREML1 is found exclusively in platelets in human peripheral blood. Upon activation, TREML1 is rapidly exposed to the platelet membrane, followed by cleavage of the extracellular domain of TREML1 (TREML1 ECD), resulting in the release of soluble TREML1. Studies have shown that patients with sepsis have high levels of soluble TREML1 in plasma, in contrast to healthy individuals. Patients who died from sepsis had sustained high levels of soluble TREML1 in plasma, whereas patients who survived showed a decline in soluble TREML1 during this same period. Indicators of immunosuppression observed in patients with sepsis include lymphocyte abnormalities, monocyte activation abrogated by reduced human leukocyte antigen-DR (HLA-DR) surface expression, and low TNF-α production under ex vivo stimulation. Sustained reduction in monocyte HLA-DR expression indicates a high risk of hospital-acquired infection and death in patients with sepsis. Recently, elevated programmed death ligand-1 (PD-L1) expression has been observed in monocytes of patients with septic shock and has been associated with increased secondary hospital-acquired infection and mortality. Previously, soluble TREML1 was reported to directly bind to immune cells and induce the cells to express an immunosuppressive phenotype, such as downregulation of HLA-DR and upregulation of PD-L1 (WO2016197975A1). High soluble TREML1 plasma concentrations have also been associated with negative outcomes in other diseases, such as acute respiratory distress syndrome, acute coronary syndrome, and coronary artery disease. These results suggest that soluble TREML1 plays an important role in inflammation-related diseases, and therefore may serve as a biomarker and therapeutic target for inflammation-related diseases.

[0005] Macrophage-1 antigen (Mac-1, integrin αMb2, CD11b / CD18) is expressed primarily on the surface of innate immune cells (including monocytes, neutrophils, NK cells, etc.) and a subpopulation of B cells (Proc. Natl. Acad. Sci. USA 2008 Apr. 1;105(13):5195-200) and T cells (J. Immunol. 2001 Jan. 15;166(2):900-7). Mac-1 is a heterodimeric glycoprotein that contains the non-covalently linked integrin αM (CD11b, CR3A, ITGAM) and integrin β2 (CD18, ITGB2). CD11b is a transmembrane protein with a large extracellular domain and a short cytoplasmic tail. The extracellular domain contains the I-domain, β-propeller domain, thigh domain, calf-1 domain, and calf-2 domain. The I-domain of CD11b has approximately 179 amino acids inserted into the β-propeller domain, which is responsible for binding to promiscuous ligands (e.g., iC3b, fibrinogen, ICAM-1, CD40L, etc.), participates in cell adhesion, migration, chemotaxis and phagocytosis, and regulates the inflammatory response of immune cells. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] WO2016197975A1 [Non-patent literature]

[0007] [Non-Patent Document 1] Proc. Natl. Acad. Sci. USA April 1, 2008;105(13):5195~200 [Non-Patent Document 2] J. Immunol. January 15, 2001;166(2):900~7 [Non-Patent Document 3] J. Goding, Monoclonal Antibodies: Principles and Practice, pp. 98-118 (NY Academic Press 1983) [Non-Patent Document 4] Kabat et al., 1992, Sequences of Proteins of Immunological Interest, 5th ed., Public Health Service, NIH, Washington DC [Non-Patent Document 5] Chothia et al., 1989, Nature 342:877-883 [Non-Patent Document 6] Lefranc, M.-P. et al., 1999, Nucleic Acids Res. 27:209~212 [Non-Patent Document 7] MacCallum et al., 1996, J. Mol. Biol. 262:732~745 Summary of the Invention [Problem to be solved by the invention]

[0008] There is a need to develop and use new targets to treat inflammation-related diseases. [Means for solving the problem]

[0009] This Summary is provided to introduce selected concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify all key features or essential features of the claimed subject matter, nor is it intended to be used solely as an aid in determining the scope of the claimed subject matter.

[0010] The present disclosure is based on the surprising discovery that TREML1 ECD can bind to the I-domain of CD11b. As a result of TREML1 ECD binding to CD11b+ immune cells, TREML1 ECD can induce immune suppression. Anti-CD11b antibodies can reverse the immune suppression induced by TREML1 ECD. Anti-TREML1 antibody treatment also reduces TREML1 ECD binding to CD11b+ immune cells. Thus, anti-TREML1 antibodies can be used to treat immunosuppressive disorders, such as cancer.

[0011] The present disclosure describes agents comprising antibodies that bind to TREML1. These antibodies can inhibit tumor growth by preventing binding of TREML1 ECD to CD11b+ immune cells. The present disclosure also describes compositions and pharmaceutical compositions comprising the agents described herein, including antibodies that bind to TREML1. In embodiments, the antibody binds to TREML1 ECD.

[0012] Additionally, the present disclosure describes methods of reversing immune suppression using agents including the antibodies described herein.

[0013] Additionally, the present disclosure describes methods of using agents such as the antibodies described herein to treat various diseases and conditions associated with immunosuppression, including cancer.

[0014] Additionally, the present disclosure describes methods for diagnosing cancer or detecting the presence of a malignancy in a subject and / or for determining whether a subject may be responsive to various cancer treatments, including immunotherapy and other forms of cancer treatment. [Brief description of the drawings]

[0015] [Figure 1]FIG. 1 shows that TREML1 ECD can bind to CD11b on human monocytes and neutrophils, and that CD11b-specific antibodies can compete with TREML1 ECD binding to CD11b+ immune cells (monocytes and neutrophils). White blood cells (WBCs) were incubated with 10 μg / ml human TREML1 ECD and 10 μg / ml anti-CD11b antibody (ICRF44). After treatment, cells were washed with staining buffer and stained with Alexa Fluor 488-conjugated anti-human TREML1 antibody (FAB2394G, R&D systems). Monocytes and neutrophils were analyzed by flow cytometry. MFI is mean fluorescence intensity. [Diagram 2] FIG. 2 shows that TREML1 ECD binds to the I-domain of CD11b in a concentration-dependent manner. [Diagram 3] Figure 3 shows that anti-CD11b antibodies can reverse immune suppression induced by TREML1. Monocytes were incubated with human TREML1 ECD (10 μg / ml) in the presence of either isotype control IgG (MOPC21) 10 μg / ml or anti-CD11b antibody (ICRF44) 10 μg / ml for 3 days. At the indicated time points, cells were harvested and analyzed by flow cytometry. HLA-DR and PD-L1 expression of isotype control IgG or anti-CD11b antibody treated monocytes is shown compared to that of mock (control) treated monocytes at the same time points. [Figure 4] FIG. 4 shows that anti-TREML1 antibodies bind to TREML1 ECD in a concentration-dependent manner. [Diagram 5]Figure 5 shows that anti-TREML1 antibodies can bind to HEK293 cells expressing human or mouse TREML1 on the cell surface. HEK293 / human TREML1 or HEK293 / mouse TREML1 were treated with 10 μg / ml of anti-TREML1 antibody or isotype control IgG (MOPC21). The cells were then incubated at 37°C for 30 minutes. The cells were then treated with APC-conjugated anti-mouse IgG antibody and analyzed by flow cytometry. [Figure 6A] Figure 6A shows that anti-TREML1 antibodies can block TREML1 ECD binding to CD11b+ immune cells (monocytes and neutrophils). WBCs were incubated with various concentrations of human TREML1 ECD and 10 μg / ml of anti-TREML1 antibody (26A6). After treatment, cells were washed with staining buffer and stained with Alexa Fluor 488-conjugated anti-human TREML1 antibody (FAB2394G, R&D systems). Monocytes and neutrophils were analyzed by flow cytometry. [Figure 6B] FIG. 6B shows that anti-TREML1 antibodies can block TREML1 ECD binding to CD11b+ immune cells (monocytes and neutrophils). WBCs were incubated with human TREML1 ECD 10 μg / ml and anti-TREML1 antibodies (18D8, 23F10, 27D3, 28A9 and 29F4) 10 μg / ml. After treatment, cells were washed with staining buffer and stained with Alexa Fluor 488-conjugated anti-human TREML1 antibody (FAB2394G, R&D systems). Monocytes and neutrophils were analyzed by flow cytometry. [Figure 7]Figure 7 shows that anti-TREML1 antibodies can reverse TREML1-induced immune suppression. Monocytes were incubated with human TREML1 ECD (1, 5, 10 μg / ml) in the presence of either isotype control IgG (MOPC21) at 10 μg / ml or anti-TREML1 antibody (26A6) at 10 μg / ml for 24 hours (hrs). Cells were harvested and analyzed for PD-L1 expression by flow cytometry. [Figure 8A] Figure 8A shows that platelet-derived TREML1 is enriched in tumors. TREML1 expression in human tissues was examined by immunostaining in formalin-fixed paraffin-embedded tissues, and the intensity of TREML1 expression in the majority of human tumors was significantly higher than that in normal tissues. The percentage of TREML-1-binding macrophages was quantified, and the fold change was calculated by dividing the percentage of TREML1 / CD68 double-positive cells in tumor tissues by that in tumor-adjacent normal tissues (NAT). Since a percentage of 0 of TREML1 / CD68 double-positive cells was found in some normal tissues, including nose, breast, uterus, prostate, ovary, kidney, skin, esophagus, and stomach (indicated by an asterisk in Figure 8A), a percentage of 1 instead of 0 was used to calculate the fold change. [Figure 8B] (B) Platelet-derived TREML1 is enriched in tumors. TREML1 (brown) can be found colocalized with macrophages (green) and distributed around the tumor stromal region. Representative photographs of human gastric cancer tissue show sites of TREML1 and macrophage colocalization (indicated by arrows), and representative photographs of colon cancer show TREML1 in the tumor (indicated by asterisks). [Figure 9]Figure 9 shows that TREML1 is highly enriched in the tumor microenvironment. In vivo monitoring of TREML1 in MC38 tumors. IVIS images of MC38 tumor-bearing mice after receiving isotype control IgG (MOPC21) or anti-TREML1 antibody (26A6) conjugated with VivoTag680XL. IVIS images of mice treated with anti-TREML1 antibody show positive bioluminescence signal (white arrow) in the MC38 tumor area. [Figure 10] 10 shows the anti-cancer effect of anti-TREML1 antibodies (26A6 and 23F10) in the MC38 colon cancer model. MC38 tumor-bearing mice were intraperitoneally treated twice weekly with 10 mg / kg anti-TREML1 antibody or isotype control IgG (MOPC21) antibody. Mice were monitored and scored for the formation of palpable tumors twice weekly. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The immune system can be divided into two categories or subsystems: the innate immune system and the adaptive immune system. Innate immunity refers to non-specific defense mechanisms that respond immediately or within hours of the presence of an antigen in a subject. These defense mechanisms include immune cells that attack physical barriers such as the skin, chemicals in the blood, and foreign cells in the body. Innate immune responses are activated by the chemical properties of antigens. In contrast, adaptive immunity refers to an antigen-specific immune response and requires the recognition of specific "non-self" antigens during the antigen presentation process. The adaptive immune response provides an adapted response to each stimulus by learning to recognize molecules it has previously encountered. Adaptive immunity also includes memory cells that maintain an adapted response to a particular antigen, so that responses to future challenges with the same antigen are more efficient.

[0017] Triggering receptors expressed by myeloid cells (TREM) belong to a family of MHC-linked receptors that contain activating and inhibitory isoforms encoded by gene clusters. TREM1 activates myeloid cells by signaling through the adaptor protein DAP12. TREM1 induces the secretion of proinflammatory chemokines and cytokines by phagocytes, amplifying bacterial and fungal-induced inflammation.

[0018] The present disclosure is based on the unexpected discovery that TREML1 ECD (soluble TREML1, soluble TLT1) binds to the I-domain of CD11b and induces immunosuppression, and that anti-CD11b antibodies can reverse TREML1 ECD-induced immunosuppression. The antibodies described herein inhibit or reduce TREML1 ECD binding to CD11b+ immune cells and reverse TREML1 ECD-induced immunosuppression. The present disclosure also describes the use of the anti-TREML1 antibodies described herein to treat various immunosuppressive disorders, including cancer, sepsis, infection, autoimmune disease, chronic disease, immune exhaustion, or immunosenescence in aging.

[0019] CD11b is constitutively expressed on the surface of leukocytes, including macrophages, monocytes, neutrophils, dendritic cells, natural killer cells, and granulocytes, which are major players in the innate immune response cellular network, and CD11b is conditionally expressed on a subset of T cells (J. Immunol. 2001 Jan. 15;166(2):900-7) and B cells (Proc. Natl. Acad. Sci. USA 2008 Apr. 1;105(13):5195-200). Thus, binding of TREML1 to the I-domain of CD11b is associated with the innate immune response. In contrast, binding of TREML1 to CD3+ and CD8+ T cells is associated with the adaptive immune response.

[0020] definition The terms "a," "an," "the," and similar referents, as used in the context of describing claimed subject matter (particularly in the context of the claims that follow), should be construed to encompass both the singular and the plural, unless otherwise indicated in the specification or clearly contradicted by context.

[0021] Amino acid residues are abbreviated as follows: alanine (Ala, A), asparagine (Asn, N), aspartic acid (Asp, D), arginine (Arg, R), cysteine ​​(Cys, C), glutamic acid (Glu, E), glutamine (Gln, Q), glycine (Gly, G), histidine (His, H), isoleucine (Ile, I), leucine (Leu, L), lysine (Lys, K), methionine (Met, M), phenylalanine (Phe, F), proline (Pro, P), serine (Ser, S), threonine (Thr, T), tryptophan (Trp, W), tyrosine (Tyr, Y) and valine (Val, V).

[0022] As will be understood by one of ordinary skill in the art, each embodiment disclosed herein can comprise, consist essentially of, or consist of its particular recited elements, steps, ingredients, or components. Thus, the term "include" or "including" should be interpreted as reciting "comprise, consist of, or consist essentially of." The transitional term "comprises" includes, but is not limited to, and permits the inclusion of unspecified elements, steps, ingredients, or components, even in large amounts. The transitional phrase "consisting of" excludes any unspecified elements, steps, ingredients, or components. The transitional phrase "consisting essentially of" limits the scope of the embodiment to the specified elements, steps, ingredients, or components and to those elements, steps, ingredients, or components that do not materially affect the embodiment. In embodiments, those elements or steps that do not affect the embodiment are elements or steps that do not alter in a statistically significant manner the ability of the embodiment to perform its in vitro or in vivo function, such as killing cancer cells in vitro or in vivo.

[0023] The term "affinity" refers to the strength of the total non-covalent interactions between a single binding site of a molecule (e.g., an antibody) and its binding partner (e.g., an antigen). Unless otherwise indicated, as used herein, "binding affinity" refers to the inherent binding affinity that reflects a 1:1 interaction between members of a binding pair (e.g., an antibody and an antigen). The affinity of a molecule X for its partner Y can generally be represented by the dissociation constant (Kd). Affinity can be measured by routine methods known in the art, including those described herein.

[0024] As used herein, the term "antibody" is used in the broadest sense and specifically encompasses monoclonal antibodies (including full-length monoclonal antibodies), polyclonal antibodies, multispecific antibodies (e.g., bispecific antibodies), monovalent antibodies, multivalent antibodies, and antibody fragments (e.g., Fabs and / or single-arm antibodies), so long as the antibody fragment exhibits the desired biological activity.

[0025] The term "antibody fragment" refers to an antibody fragment that contains a portion of an intact antibody. An antibody fragment can retain its binding to the antigen to which the intact antibody binds. Examples of such antibody fragments include Fv, Fab, Fab', Fab'-SH, F(ab')2, diabodies, linear antibodies, single chain antibodies (scFv), and multispecific antibodies formed from antibody fragments.

[0026] The term "antigen-binding fragment" or "antigen-binding portion" of an antibody refers to one or more portions of an antibody that retain the ability to specifically bind to an antigen. It has been shown that the antigen-binding function of an antibody can be performed by fragments of a full-length antibody. Examples of binding fragments encompassed by the term "antigen-binding fragment" of an antibody include (i) a Fab fragment, which is a monovalent fragment consisting of the VL, VH, CL and CH1 domains; (ii) a F(ab')2 fragment, which is a bivalent fragment containing two Fab fragments linked by a disulfide bridge at the hinge region; (iii) an Fd fragment consisting of the VH and CH1 domains; (iv) an Fv fragment consisting of the VL and VH domains of a single arm of an antibody; (v) a dAb fragment consisting of the VH domain; and (vi) an isolated complementarity determining region (CDR). These antibody fragments are obtained using conventional techniques, such as the proteolytic fragmentation techniques described in J. Goding, Monoclonal Antibodies: Principles and Practice, pp. 98-118 (NY Academic Press 1983). The fragments are screened for utility in the same manner as are intact antibodies.

[0027] As used herein, the term "complementarity determining region" (CDR) refers to the region in an antibody where these proteins complement the shape of an antigen. The acronym CDR is used herein to mean "complementarity determining region". Since a single antibody has two antigen receptors, it has 12 CDRs. There are three CDR loops per variable region in an antibody.

[0028] The "variable region" of an antibody refers to the variable region of an antibody light chain or the variable region of an antibody heavy chain, either alone or in combination. The variable regions of the heavy and light chains each consist of four framework regions (FRs) connected by three CDRs, also known as hypervariable regions. The CDRs of each chain are closely bound by the FRs and contribute, together with the CDRs of the other chain, to the formation of the antigen-binding site of the antibody. Exemplary conventional methods that can be used to identify the boundaries of CDRs include, for example, the Kabat definition and the Chothia definition. The Kabat definition is based on sequence variability (see Kabat et al., 1992, Sequences of Proteins of Immunological Interest, 5th ed., Public Health Service, NIH, Washington DC), and the Chothia definition is based on the location of structural loop regions (Chothia et al., 1989, Nature 342:877-883). Other approaches to CDR identification include the "IMGT definition" (Lefranc, M.-P. et al., 1999, Nucleic Acids Res. 27:209-212), and the "AbM definition," a compromise between Kabat and Chothia, obtained using Oxford Molecular's AbM antibody modeling software, or the "contact definition" of CDRs based on observed antigen contacts, as set forth in MacCallum et al., 1996, J. Mol. Biol. 262:732-745. As used herein, CDR may refer to CDRs defined by the Kabat numbering system.

[0029] The term "humanized antibody" or "humanized antibody fragment" refers to a specific type of chimeric antibody that comprises an immunoglobulin amino acid sequence variant or fragment thereof that is capable of binding to a given antigen and that comprises one or more framework (FR) regions having substantially the amino acid sequence of a human immunoglobulin and one or more complementarity determining regions (CDRs) having substantially the amino acid sequence of a non-human immunoglobulin. This non-human amino acid sequence, often referred to as an "import" sequence, is typically taken from an "import" antibody domain, particularly the variable region. Generally, a humanized antibody comprises at least the CDRs or hypervariable regions (HVLs) of a non-human antibody inserted between the FRs of a human heavy or light chain variable region.

[0030] The term "human antibody" refers to an antibody possessing an amino acid sequence which corresponds to that of an antibody produced by a human or human cell, or derived from a non-human source that utilizes the human antibody repertoire or other human antibody-encoding sequences. Human antibodies specifically exclude humanized antibodies which contain non-human antigen-binding residues.

[0031] The term "chimeric antibody" refers to an antibody that contains one or more regions from one antibody and one or more regions from one or more other antibodies.

[0032] As used herein, the term "heavy chain" includes full-length heavy chains and fragments thereof having sufficient variable region sequence to confer epitope specificity. A full-length heavy chain contains a variable region, VH or VH, and three constant region domains, CH1, CH2, and CH3. The VH domain is at the amino-terminus of the polypeptide, and the CH3 domain is at the carboxyl-terminus.

[0033] The term "light chain" includes full-length light chains and fragments thereof having sufficient variable region sequence to confer epitope specificity. A full-length light chain contains a variable region, VL or VL, and a constant region domain, CL. Like the heavy chain, the variable region of the light chain is at the amino-terminus of the polypeptide.

[0034] The term "CD11b" refers to integrin alpha M (ITGAM, CR3A), one subunit of the heterodimeric integrin αMβ2. The second subunit of integrin αMβ2 is the common integrin β2 subunit known as CD18. Integrin αMβ2, also called macrophage-1 antigen (Mac-1) or complement receptor 3 (CR3), is constitutively expressed on the surface of white blood cells, including monocytes, neutrophils, granulocytes, macrophages, dendritic cells, and natural killer cells, and conditionally expressed on a subset of T cells (J. Immunol. 2001 Jan. 15; 166(2):900-7) and B cells (Proc. Natl. Acad. Sci. USA 2008 Apr. 1; 105(13):5195-200).

[0035] The term "PD-L1" refers to programmed death-ligand 1 (PD-L1), cluster of differentiation 274 (CD274), or B7 homolog 1 (B7-H1). PD-L1 is a transmembrane protein that plays a major role in suppressing the immune system.

[0036] The term "PD-1" refers to programmed death protein 1, also known as CD279. It is a protein on the surface of T and B cells that downregulates the immune system. PD-1 plays an important role in inhibiting immune responses and promoting self-tolerance by modulating the activity of T cells. PD-1 and its ligand, PD-L1, inhibit T cell activation, proliferation, survival and cytotoxic secretion in cancer cells. PD-1 and PD-L1 have been reported to be involved in suppressing the immune system in autoimmune diseases, cancer, rheumatoid arthritis, neurodegenerative diseases, sepsis and other infectious diseases such as tuberculosis, cytomegalovirus and hepatitis.

[0037] The term "monocyte", also called mononuclear leukocyte, belongs to a recognized type of white blood cell involved in first line defense mechanisms and capable of differentiating into dendritic cells or macrophage precursors. Monocytes normally migrate within the blood system. In response to external stimulatory signals, monocytes secrete a number of immunomodulatory cytokines, migrate to sites of infection in tissues, and differentiate into macrophages.

[0038] The term "modulating" includes "increasing," "inducing," "promoting," or "stimulating," as well as "decreasing," "reducing," or "inhibiting" in a statistically significant or physiologically significant amount compared to a control.

[0039] The terms "inhibiting" and "reversing" are used interchangeably in the context of immunosuppression to mean alleviating or reducing the suppression of an immune response.

[0040] The term "pharmaceutically acceptable carrier" refers to an ingredient in a pharmaceutical formulation, other than an active ingredient, that is non-toxic to a subject. Pharmaceutically acceptable carriers include buffers, excipients, stabilizers, or preservatives.

[0041] The term "effective amount" refers to an amount sufficient to effect a beneficial or desired clinical result. An effective amount can be administered in one or more administrations.

[0042] The term "therapeutic" refers to treatment and / or prophylaxis. A therapeutic effect is achieved by preventing, mitigating or eradicating a disease state, or alleviating the symptoms of a disease state.

[0043] The term "therapeutically effective amount" refers to an amount of a composition or agent that elicits a biological or medical response in a tissue, system, or subject as desired by a researcher, veterinarian, physician, or another clinician. The term "therapeutically effective amount" includes an amount of a compound that, when administered, is sufficient to prevent or alleviate to some extent one or more of the signs or symptoms of the disease or condition being treated. The therapeutically effective amount varies depending on the agent, the disease and its severity, and the age, weight, etc., of the subject being treated. A therapeutically effective amount is an amount that is sufficient to diagnose, alleviate, ameliorate, stabilize, reverse, inhibit, slow or delay the progression of a disease state or cellular process.

[0044] The terms "treatment", "treating" or "treating" and the like generally refer to obtaining a desired pharmacological and / or physiological effect. The effect may be prophylactic, in that a disease or its symptoms are completely or partially prevented, and / or may be therapeutic, in that a disease and / or deleterious effects resulting from the disease are partially or completely stabilised or cured. Treatment includes any treatment of disease in a mammal, particularly a human: (a) inhibiting one or more disease symptoms in a subject, i.e., preventing their development from occurring; or (b) relieving, ameliorating or alleviating one or more disease symptoms in a subject, i.e., causing regression of the disease or symptoms.

[0045] The term "prevent" or "prevention" refers to a preventative or prophylactic measure that prevents the onset, recurrence, or spread of a disease state or condition, or one or more symptoms of a disease state or condition, from occurring in a subject. This term includes administration of a composition or agent described herein to a subject at risk of developing a disease state or condition prior to the onset of symptoms. This term includes the inhibition or reduction of one or more symptoms associated with a disease state or condition. The term "prevention" may be used interchangeably with the term "prophylactic treatment."

[0046] The term "immune checkpoint blockade (ICB) therapy" refers to cancer immunotherapy using immune checkpoint inhibitors, such as anti-PD-L1, anti-CTLA-4 and anti-PD-1 antibodies. Anti-PD-1, anti-CTLA-4 and anti-PD-L1 monoclonal antibodies have been reported to provide durable responses in patients with various cancers.

[0047] The term "responsive to a treatment that may be administered as a form of cancer treatment" or "responsive to a cancer treatment" refers to a subject diagnosed with cancer or malignant tumor growth and responds to or benefits from one or more treatments that may be administered to treat the cancer. The subject is not resistant to the one or more treatments and responds to or benefits from the treatment, such as inhibiting the growth of cancer cells or tumors or reducing the size of cancer cells or tumors. An example of a cancer treatment is immunotherapy, including ICB therapy.

[0048] The terms "all treatments" or "treatments" may be used interchangeably and may include one or more cancer therapies and / or a variety of cancer therapies that may be administered as a form of cancer treatment.

[0049] The term "subject" includes humans or non-human animals. Non-human animals include mammals, such as mice, rats, dogs, pigs, monkeys and apes, and non-mammals, such as birds, reptiles, fish and amphibians. Subjects in need or in need of treatment include subjects having a disease or condition in need of treatment. Subjects in need also include subjects in need of treatment or prevention of a disease or condition. In an embodiment, the disease or condition is an immunosuppressive disease, including cancer.

[0050] The term "sequence identity" refers to the relationship between two or more polypeptide or polynucleotide sequences, as determined by comparing their sequences. The term "sequence identity" also refers to the degree of sequence relatedness between polypeptide or polypeptide sequences, as determined by the match between strings of polypeptide sequences. Sequence identity can be readily calculated by known bioinformatics methods. As an example, the "percent identity" of two polynucleotide or two polypeptide sequences is determined by comparing the sequences using the GAP computer program (part of the GCG Wisconsin Package, version 10.3 (Accelrys, San Diego, Calif.)) using its default parameters.

[0051] The recitation of ranges of values ​​herein is intended merely to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated herein as if it were individually recited herein. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the present disclosure. Thus, the description of a range should be considered to have all possible subranges and individual numerical values ​​specifically disclosed within that range. For example, the description of a range such as 1-6 should be considered to have specifically disclosed subranges such as 1-3, 1-4, 1-5, 2-4, 2-6, 3-6, etc., as well as individual numerical values ​​within that range, such as 1, 2, 2.5, 2.7, 3, 4, 5, 5.1, 5.3, 5.8, and 6. This applies regardless of the breadth of the range. Furthermore, any range cited herein includes the upper and lower limits of the range.

[0052] Where further clarity is needed, the term "about," when used in conjunction with a stated numerical value or range, has the meaning that a person of ordinary skill in the art would reasonably ascribe to it, i.e., some more or some less than the stated value or range, ±20% of the stated value; ±15% of the stated value; ±10% of the stated value; ±5% of the stated value; ±4% of the stated value; ±3% of the stated value; ±2% of the stated value; ±1% of the stated value; or within any percentage range between ±1% and 20% of the stated value.

[0053] Agents that bind to TREML1 and compositions thereof The present disclosure describes agents that bind to TREML1 and reverse immune suppression induced by TREML1 binding to CD11b. Agents that bind to TREML1 include any compound or molecule that can bind to TREML1 ECD and reverse immune suppression induced by TREML1 binding to CD11b. In embodiments, agents described herein include antibodies that bind to TREML1 ECD.

[0054] The antibodies described herein include monoclonal antibodies, polyclonal antibodies, chimeric antibodies, bispecific antibodies, humanized antibodies, and antigen-binding fragments thereof. These antibodies bind to TREML1 and reverse the immune suppression induced by TREML1 binding to CD11b. In embodiments, these antibodies bind to TREML1 ECD. The antibodies described herein can be obtained by any known method, including phage display technology, recombinant technology, computer technology, hybridoma technology, or immunizing animals. As an example, the antibodies described herein can be obtained by immunizing mice with human TREML1 antigen, followed by screening and isolating hybridomas that have specific antibody genes that can recognize TREML1 ECD.

[0055] Exemplary antibodies that bind to TREML1 are shown below in Tables 1 to 3. As indicated by the consensus or conserved sequences in Tables 1, the present disclosure describes antibodies that bind to TREML1, comprising a VH region comprising amino acid sequence SEQ ID NO:20 (CDR-H1), SEQ ID NO:29 (CDR-H2) and SEQ ID NO:30 (CDR-H3), and a VL region comprising amino acid sequence SEQ ID NO:31 (CDR-L1), SEQ ID NO:24 (CDR-L2) and SEQ ID NO:25 (CDR-L3). As shown by the consensus or conserved sequences in Tables 2 (Tables 3 and 4), the present disclosure describes an antibody that binds to TREML1, comprising a VH region comprising amino acid sequence SEQ ID NO: 49 (CDR-H1), SEQ ID NO: 50 (CDR-H2) and SEQ ID NO: 51 (CDR-H3), and a VL region comprising SEQ ID NO: 52 (CDR-L1), SEQ ID NO: 53 (CDR-L2) and SEQ ID NO: 54 (CDR-L3). In embodiments, the amino acid "X" in the amino acid sequences of the CDRs can be any amino acid.

[0056] Amino acids differ from each other in terms of their side chains (or R groups). For example, their side chains may differ in structure, charge and polarity. There are three types of polar amino acids: neutral amino acids, positively charged amino acids and negatively charged amino acids. Polar amino acids with uncharged side chains include serine (S), threonine (T), cysteine ​​(C), proline (P), asparagine (N) and glutamine (Q). Polar amino acids with positively charged side chains include lysine (K), arginine (R) and histidine (H), and polar amino acids with negatively charged side chains include aspartic acid (D) and glutamic acid (E). Nonpolar amino acids with aliphatic or hydrophobic side chains include alanine (A), isoleucine (I), leucine (L), methionine (M), glycine (G), and valine (V), and nonpolar amino acids with aromatic side chains include phenylalanine (F), tryptophan (W), and tyrosine (Y).

[0057] In embodiments, based on the sequences shown in Table 1 (Tables 1 and 2) and Table 2 (Tables 3 and 4), the amino acid "X" can be a specific amino acid as shown in the following examples. In SEQ ID NO: 29, the first amino acid X can comprise a polar amino acid with an uncharged or positively charged side chain, e.g., S or R, and the second amino acid X can comprise a nonpolar amino acid with an aliphatic side chain, e.g., V or I. In SEQ ID NO: 30, the first amino acid X can comprise a polar amino acid with an uncharged or negatively charged side chain, e.g., D or N, and the second amino acid X can comprise a nonpolar amino acid with an aliphatic side chain, e.g., I or M. In SEQ ID NO: 31, the amino acid X can comprise a polar amino acid with an uncharged side chain, e.g., N or S. In SEQ ID NO: 49, the first amino acid X can comprise a polar amino acid with a negative or uncharged side chain, e.g., D, E, or N, and the second amino acid X can comprise a nonpolar amino acid with an aliphatic side chain, e.g., I or M.In SEQ ID NO:50, the first amino acid X may comprise a non-polar amino acid with an aliphatic or aromatic side chain, e.g., I, M, or F; the second amino acid X may comprise a polar amino acid with an uncharged side chain, e.g., T or N; the third amino acid X may comprise a polar amino acid with a negatively charged side chain, e.g., D, or a non-polar amino acid with an aliphatic side chain, e.g., G; the fourth amino acid X may comprise a non-polar amino acid with an aliphatic side chain, e.g., G, or a polar amino acid with a positively charged side chain, e.g., H; the fifth amino acid X may comprise a polar amino acid with an uncharged side chain, e.g., P or S, or a non-polar amino acid with an aliphatic side chain, e.g., A; the sixth amino acid X may comprise a non-polar amino acid with an aromatic side chain, e.g., H, or a non-polar amino acid with an aromatic side chain. The seventh amino acid X may comprise a polar amino acid with an uncharged side chain, such as S or N; the eighth amino acid X may comprise a polar amino acid with a negatively charged side chain, such as D or E; the ninth amino acid X may comprise a polar amino acid with a positively charged or uncharged side chain, such as K or T; the tenth amino acid X may comprise a nonpolar amino acid with an aliphatic or aromatic side chain, such as I, A or F; the eleventh amino acid X may comprise a polar amino acid with a positively charged or uncharged side chain, such as K, R or T; the twelfth amino acid X may comprise a polar amino acid with a negatively charged side chain, such as D, or a nonpolar amino acid with an aliphatic side chain, such as G. In SEQ ID NO:51, the amino acid X may comprise a nonpolar amino acid with an aromatic side chain, such as F or Y. In SEQ ID NO:52, the first amino acid X may comprise a polar amino acid with a positively charged side chain, e.g., R or K; the second amino acid X may comprise a polar amino acid with an uncharged side chain, e.g., S or T; the third amino acid X may comprise a nonpolar amino acid with an aliphatic side chain, e.g., L, V or I; and the fourth amino acid X may comprise a nonpolar amino acid with an aliphatic side chain, e.g., L or V. In SEQ ID NO:53, the amino acid X may comprise a polar amino acid with a positively charged or uncharged side chain, e.g., K or Q.In SEQ ID NO:54, the first amino acid X may comprise a polar amino acid with an uncharged side chain, e.g., T or S; the second amino acid X may comprise a polar amino acid with a positively charged side chain, e.g., H, or a nonpolar amino acid with an aromatic side chain, e.g., Y; and the third amino acid X may comprise a nonpolar amino acid with an aliphatic side chain, e.g., I or V. The "X" amino acids in each sequence set forth above are numbered consecutively with the first X amino acid closest to the amino terminus of the peptide.

[0058] Table 1: CDRs of exemplary antibodies [Table 1] [Table 2]

[0059] Table 2: CDRs of exemplary antibodies [Table 3] [Table 4]

[0060] In an embodiment, the anti-TREML1 antibody comprises a V H and V L The exemplary antibody described herein includes various clones containing the amino acid sequence SEQ ID NO:4 (V H ) and SEQ ID NO:5(V L ) containing clone 17E6; SEQ ID NO:6 (V H ) and SEQ ID NO: 7 (V L ) containing clone 25C6; SEQ ID NO: 8 (V H ) and SEQ ID NO: 9 (V L ) containing clone 26A6; SEQ ID NO: 10 (V H ) and SEQ ID NO: 11 (V L ) containing clone 18D8; SEQ ID NO: 12 (VH ) and SEQ ID NO: 13 (V L ) containing clone 23F10; SEQ ID NO: 14 (V H ) and SEQ ID NO: 15 (V L ) containing clone 27D3; SEQ ID NO: 16 (V H ) and SEQ ID NO: 17 (V L ), clone 28A9 containing SEQ ID NO: 18 (V H ) and SEQ ID NO: 19 (V L ) containing clone 29F4.

[0061] Table 3: Exemplary anti-TREML1 antibodies The CDR sequences of each antibody are underlined. [Table 5] [Table 6] [Table 7] [Table 8] [Table 9] [Table 10] [Table 11] [Table 12]

[0062] The present disclosure also describes compositions comprising one or more agents that bind to TREML1 and reverse immune suppression induced by TREML1 binding to CD11b, including antibodies that bind to TREML1 ECD as described herein. The compositions may also include a carrier. In an embodiment, the composition is a pharmaceutical composition. The pharmaceutical composition may include a pharma- ceutically acceptable carrier.

[0063] The term "carrier" includes diluents, adjuvants, or excipients that can be added to a composition and do not affect the active ingredients, particularly the antibodies described herein. Examples of adjuvants include complete and incomplete Freund's adjuvant used in animals, particularly laboratory animals. Pharmaceutically acceptable carriers include sterile liquids, such as water, and oils, including those from petroleum, animal, vegetable, or synthetic origin, such as peanut oil, soybean oil, mineral oil, sesame oil, and the like. Water is a preferred excipient when the pharmaceutical composition is administered intravenously. Physiological saline and aqueous dextrose and glycerol solutions can also be used as liquid excipients, particularly for injectable solutions. Suitable pharmaceutical excipients include starch, glucose, lactose, sucrose, gelatin, malt, rice, wheat, chalk, silica gel, sodium stearate, glycerol monostearate, talc, sodium chloride, nonfat dry milk, glycerol, propylene, glycol, water, ethanol, and the like.

[0064] The compositions or pharmaceutical compositions described herein may also contain small amounts of wetting or emulsifying agents, or pH buffering agents. These compositions may take the form of solutions, suspensions, emulsions, tablets, pills, capsules, powders, sustained release formulations, and the like. Pharmaceutical compositions may be prepared as formulations. Oral formulations may contain standard carriers, such as pharmaceutical grades of mannitol, lactose, starch, magnesium stearate, sodium saccharin, cellulose, magnesium carbonate, and the like. Such formulations contain a therapeutically effective amount of the antibodies described herein in purified form, together with a suitable amount of carrier to provide the form for proper administration to the subject. The formulation should suit the mode of administration.

[0065] The administration of the pharmaceutical compositions described herein can be carried out in any conventional manner, including by aerosol inhalation, injection, ingestion, injection, implantation or implantation. The compositions described herein can also be administered to a subject orally, topically, intranasally, enterally, rectally, bucally, vaginally, sublingually, subcutaneously, intradermally, intratumorally, intranodal, intramedullary, intramuscularly, intravenously, intracranially, intraperitoneally, or combinations thereof. The administration of the pharmaceutical composition can be in any manner that is effective to deliver a therapeutically and / or prophylactically effective amount of the conjugates described herein to a subject in need thereof.

[0066] The terms "immunologically effective amount", "anti-tumor effective amount", "tumor inhibiting effective amount", "therapeutic amount" or "effective amount" refer to the precise amount of active ingredient, e.g., an antibody described herein, to be administered, which can be determined by a physician taking into account individual differences in age, weight, tumor size, extent of infection or metastasis and condition of the subject.

[0067] The dosage for administering the pharmaceutical compositions described herein to a subject varies depending on the exact nature of the condition being treated and the recipient of the treatment. Setting the dosage for human administration can be performed by a physician according to accepted practices in the art, depending on various factors described herein. The optimal dosage and treatment regime for a particular subject can be easily determined by a physician, taking into account parameters such as physical, physiological and psychological factors, including the target, body weight, stage of the disease and route of administration.

[0068] Exemplary doses of pharmaceutical compositions including agents such as antibodies described herein can include 0.0001 mg / kg to 200 mg / kg of subject's body weight. A total daily dose can be 0.1 mg / kg to 50.0 mg / kg administered to a subject 1 to 3 times per day. Additional useful doses can often range from 0.1 μg / kg to 5 μg / kg, 5 μg / kg to 100 μg / kg, 50 μg / kg to 500 μg / kg, 450 μg / kg to 1 mg / kg, 1 mg / kg to 10 mg / kg, 5 mg / kg to 50 mg / kg, 25 mg / kg to 75 mg / kg, 50 mg / kg to 100 mg / kg, 75 mg / kg to 125 mg / kg, 100 mg / kg to 150 mg / kg, 125 mg / kg to 175 mg / kg, or 150 mg / kg to 200 mg / kg. The exemplary doses given are based on the subject's body weight.

[0069] Uses of the agents described herein Embodiments relate to agents described herein that can reduce soluble TREML1 binding to CD11b+ immune cells and their use to reverse TREML1-induced immune suppression. Anti-TREML1 antibodies provide novel potential treatments for diseases and conditions associated with immune suppression.

[0070] Agents described herein include anti-TREML1 antibodies that bind to TREML1 on HEK293 / TREML1 cells and CD11b+ immune cells. As a result of the anti-TREML1 antibodies binding innate immune cells and competing with the TREML1 ECD for binding to innate immune cells, the anti-TREML1 antibodies can be used to treat cancer.

[0071] The present disclosure describes a method comprising administering one or more agents, including the antibodies described herein, and pharmaceutical compositions described herein, to a subject in need thereof to treat or alleviate one or more symptoms of a disease or condition associated with or characterized by immunosuppression. In an embodiment, reversing immunosuppression comprises inhibiting an inflammatory response, such as a monocyte-mediated, macrophage-mediated, and / or neutrophil-mediated inflammatory response. In an embodiment, the disease or condition comprises malignant tumor growth, tumor angiogenesis, cancer, chronic infection, sepsis, immune exhaustion, or immunosenescence in aging.

[0072] Examples of cancers and malignant tumors include melanoma, lung cancer, squamous cell carcinoma of the lung, head and neck cancer, breast cancer, ovarian cancer, uterine cancer, prostate cancer, stomach cancer, cervical cancer, esophageal cancer, bladder cancer, kidney cancer, brain cancer, liver cancer, colon cancer, bone cancer, pancreatic cancer, skin cancer, cutaneous or intraocular malignant melanoma, ovarian cancer, rectal cancer, cancer of the anal region, stomach cancer, testicular cancer, cancer of the fallopian tubes, cancer of the endometrium, cancer of the cervix, cancer of the vagina, cancer of the vulva, Hodgkin's disease, non-small cell lung cancer, and ovarian cancer. Hodgkin's lymphoma, esophageal cancer, small intestine cancer, endocrine system cancer, thyroid cancer, parathyroid cancer, adrenal cancer, sarcoma of soft tissue, urethral cancer, penile cancer, chronic or acute leukemia, solid tumors of childhood, lymphocytic lymphoma, renal pelvis cancer, central nervous system (CNS) neoplasm, primary CNS lymphoma, spinal axis tumor, brain stem glioma, pituitary adenoma, Kaposi's sarcoma, epidermoid carcinoma, squamous cell carcinoma, T-cell lymphoma and gastrointestinal cancer. Examples of chronic or acute leukemia include acute myeloid leukemia, chronic myelogenous leukemia, acute lymphoblastic leukemia and chronic lymphocytic leukemia. In an embodiment, the cancer or malignant tumor is colon cancer.

[0073] The present disclosure also describes methods of using one or more agents, including the antibodies described herein, or the pharmaceutical compositions described herein, to inhibit binding of TREML1 to CD11b.

[0074] Additionally, the present disclosure describes methods of using one or more agents, including the antibodies described herein, or the pharmaceutical compositions described herein, to reverse immune suppression in a cell.

[0075] Additionally, the present disclosure describes methods of using one or more agents, including the antibodies described herein, or the pharmaceutical compositions described herein, to inhibit the growth of cancer cells or malignant tumors.

[0076] In addition, the disclosure describes methods of using one or more agents comprising an antibody described herein, or a pharmaceutical composition described herein, to inhibit PD-L1 expression on a cell, the method comprising administering an agent comprising an antibody described herein, or a pharmaceutical composition described herein, to a cell induced to express PD-L1 by TREML1-binding CD11b.

[0077] Furthermore, the present disclosure describes a method of using one or more anti-CD11b antibodies to block the interaction between TREML1 and CD11b and reverse immune suppression induced by TREML1. The I-domain of CD11b is a receptor for TREML1. Anti-CD11b antibodies can normalize the level of HLA-DR expression and reduce the level of PD-L1 expression associated with immune suppression.

[0078] In embodiments, the methods described herein include administering one or more agents, including an antibody described herein, or a pharmaceutical composition described herein, to a cell in vitro, ex vivo, or in vivo, e.g., in a subject. The cell includes an immune cell. In embodiments, the cell includes one or more cells of the immune response system. Examples of such cells include macrophages, neutrophils, monocytes, dendritic cells, natural killer cells, granulocytes, subsets of T cells (J. Immunol. 2001 Jan. 15; 166(2):900-7), and subsets of B cells (Proc. Natl. Acad. Sci. USA 2008 Apr. 1; 105(13):5195-200).

[0079] In embodiments, the methods described herein reverse cellular immunosuppression and / or treat a disease or condition associated with immunosuppression.

[0080] In an embodiment, the method described herein comprises administering one or more agents, including an antibody described herein, or a pharmaceutical composition described herein, to an immune cell. The immune cell may be a cell of the innate immune response system. Examples of cells of the innate immune response system include macrophages, monocytes, dendritic cells, natural killer cells, neutrophils, and granulocytes. In an embodiment, the cell is present in a subject. In an embodiment, the subject is a mammal.

[0081] In embodiments, the methods described herein reverse cellular immunosuppression and / or treat a disease or condition associated with immunosuppression.The methods described herein inhibit inflammation.

[0082] The present disclosure also describes TREML1 as a marker useful for diagnosing cancer and identifying subjects for various forms of cancer treatment. Accordingly, the present disclosure also describes a method for diagnosing cancer or detecting the presence of malignancy in a subject and / or for determining whether the subject may be responsive to one or more treatments that may be administered as a form of cancer treatment. Such a method comprises obtaining a biological sample from a subject and detecting the presence of TREML1 in the sample, thereby detecting cancer or malignancy in the subject and / or identifying the subject for one or more cancer treatments. In an embodiment, the method described herein further comprises quantifying the expression of TREML1 in the sample. The method may further comprise comparing the expression of TREML1 in the subject with the expression of TREML1 in a control. The control may be a healthy subject or a reference value associated with the expression of TREML1 in a healthy subject or normal control. If expression of TREML1 in the subject is higher than the control, it indicates that the subject has cancer or a malignant tumor and / or is a candidate for one or more therapies that may be administered as a form of cancer treatment.

[0083] In embodiments, detecting the presence of TREML1 may include performing an immunological assay, a histological assay, a cytological assay, an enzyme-linked immunosorbent assay (ELISA), a bead-based detection assay, a DNA or RNA expression assay, or an aptamer-based assay. In embodiments, the method is performed using one or more agents, including the antibodies described herein, or the pharmaceutical compositions described herein.

[0084] In embodiments, the biological samples described herein include bodily fluids, cells or tissues, optionally where the bodily fluids include blood, urine, saliva, bile, bone marrow aspirate, breast milk, cerebrospinal fluid (CSF), plasma, serum, stool, vaginal fluid or synovial fluid; optionally where the cells include blood cells, epithelial cells, fibroblasts, liver cells, immune cells (e.g. T cells, B cells, NK cells, monocytes, macrophages, dendritic cells, etc.), stem cells, peripheral blood cells or stem cells; optionally where the tissue is tissue from a biopsy or resected tumor.

[0085] Examples of cancers and malignant tumors are described herein. In embodiments, the cancer or malignant tumor comprises a cancer of the gastrointestinal tract, such as colon cancer.

[0086] In an embodiment, a subject diagnosed with cancer or malignant tumor or identified for cancer treatment may be treated with one or more cancer therapies, such as chemotherapy, radiation therapy, immunotherapy, and stem cell or bone marrow transplantation therapy. As an example, a subject diagnosed with or identified with cancer is a candidate for immunotherapy, including ICB therapy, where immune checkpoint blockade or immune checkpoint inhibitors may be used to treat the subject.

[0087] In an embodiment, the method further comprises treating the subject with ICB therapy. ICB therapy includes checkpoint inhibitors and monoclonal antibody-based therapy that block the interaction of inhibitory receptors (immune checkpoints) expressed on the surface of immune cells with their ligands. As an example, expression of PD-1 and PD-L1 is increased in certain cancer patients in response to PD-1 blockade. ICB therapy involving blocking PD-L1 includes administering atezolizumab (Tecentriq®), avelumab (Fotivda®) or durvalumab (Imfinzi®). Atezolizumab is an FDA-approved immunotherapy that has been shown to be effective in treating non-small cell lung cancer (NSCLC), small cell lung cancer, hepatocellular carcinoma, triple-negative breast cancer, and urothelial cancer, including bladder cancer. Avelumab is an FDA-approved drug for treating skin cancers, including Merkel cell carcinoma and urothelial carcinoma. Durvalumab is an FDA-approved immunotherapy for treating NSCLC.

[0088] ICB therapy using PD-1 inhibitors includes pembrolizumab (Keytruda®), nivolumab (Opdivo®) and cemiplimab (Libtayo®). Pembrolizumab was approved for medical use in the United States in 2014 and is used to treat melanoma, lung cancer, head and neck cancer, Hodgkin's lymphoma, gastric cancer, cervical cancer and certain types of breast cancer. Nivolumab has been approved for medical use since 2014 and is used to treat melanoma, lung cancer, malignant pleural mesothelioma, renal cell carcinoma, Hodgkin's lymphoma, head and neck cancer, urothelial carcinoma, colon cancer, esophageal squamous cell carcinoma, liver cancer, gastric cancer, and esophageal or gastroesophageal junction cancer. Cemiplimab is used to treat squamous cell carcinoma. In 2018, cemiplimab was approved for the treatment of patients with metastatic squamous cell carcinoma (CSCC) or locally advanced CSCC who are not candidates for curative surgery or therapeutic radiation.

[0089] Another example of a checkpoint inhibitor is a CTLA-4 inhibitor. CTLA-4 is a checkpoint protein on T cells that acts as a kind of "off switch" that helps suppress the immune system. CTLA-4 downregulates the immune system. ICB therapy using CTLA-4 inhibitors includes ipilimumab (Yervoy®). Ipilimumab turns off the inhibitory mechanisms of cytotoxic T lymphocytes (CTLs) and enhances the body's immune response to cancer cells. Ipilimumab has been approved for the treatment of skin cancer since 2011. It is in clinical trials for the treatment of other cancers, including NSCLC, SCLC, bladder cancer, and metastatic hormone-refractory prostate cancer.

[0090] In embodiments, a subject diagnosed with cancer or a malignant tumor and / or identified as being responsive to cancer treatment may be treated with one or more agents, including the antibodies described herein, or the pharmaceutical compositions described herein.

[0091] In an embodiment, the subject may be treated with any treatment that may be administered as a form of cancer treatment, including immunotherapy such as ICB therapy, targeted therapy, chemotherapy, radiation therapy, surgery, and other cancer treatments. In an embodiment, the subject may be treated with a combination of treatments described herein. In an embodiment, the subject may be treated with a treatment that may be administered as a form of cancer treatment, and one or more agents including the antibodies described herein, or the pharmaceutical compositions described herein.

[0092] The present disclosure also describes a kit for diagnosing cancer, detecting malignancies, and / or identifying a subject for treatments that may be administered as a form of cancer treatment. In an embodiment, the kit contains one or more agents, including the antibodies described herein, for detecting expression of TREML1 in a biological sample from a subject. The kit may also include a container or device for collecting a biological sample from a subject, and a container or device for mixing an agent with the biological sample, for detecting cancer or malignant tumor growth and / or determining whether the subject is a candidate for various treatments that may be administered as a form of cancer treatment. Additionally, the kit may include a reference standard or control for comparison. Additionally, the kit may include instructions for using one or more agents.

[0093] In addition, the present disclosure describes a kit for treating a subject diagnosed with cancer. In an embodiment, the kit includes one or more agents, including one or more antibodies described herein, or a pharmaceutical composition described herein. In an embodiment, the kit includes all therapies that can be administered as a form of cancer treatment, and one or more agents, such as one or more antibodies described herein, or a pharmaceutical composition described herein. The kit may include means for administering one or more cancer treatments, including immunotherapy such as ICB, including administering a checkpoint inhibitor or antibody as a form of cancer treatment. The kit may also include means, such as a device or apparatus, for administering one or more agents and / or one or more cancer treatments described herein to a subject. Furthermore, the kit may include instructions for using one or more agents described herein, or one or more agents described herein in combination with one or more cancer treatments to treat a subject.

[0094] The following exemplary embodiments and examples illustrate the exemplary methods provided herein. These exemplary embodiments and examples are not intended to limit the scope of the present disclosure, and they should not be interpreted as limiting the scope of the present disclosure. It is clear that the method may be performed differently from the method specifically described herein. In light of the teachings herein, many modifications and variations are possible, and therefore, are within the scope of the present disclosure.

[0095] Exemplary embodiments The following are exemplary embodiments: 1. An agent that inhibits the binding of triggering receptor expressed by myeloid cells (TREM)-like transcript-1 (TREML1) to CD11b, optionally where TREML1 is present in a soluble form. 2. The agent of embodiment 1, wherein CD11b is expressed on immune cells, optionally wherein CD11b is constitutively expressed on one or more leukocytes including macrophages, monocytes, neutrophils, dendritic cells, natural killer cells and granulocytes, and optionally wherein CD11b is conditionally expressed on a subset of T cells and B cells. 3. The agent of embodiment 1 or 2, comprising an anti-TREML1 antibody or an antigen-binding fragment thereof. 4. i) a heavy chain variable (VH) region, comprising: heavy chain complementarity determining region 1 (CDR-H1) comprising DYGMA (SEQ ID NO: 20); CDR-H2 comprising FISNLAYX1X2YYADTVTG (SEQ ID NO: 29); and CDR-H3 comprising EDYGX3NGAX4DY (SEQ ID NO: 30); and a light chain variable (VL) region, comprising: a light chain complementarity region 1 (CDR-L1) comprising RSSQX5IVHSNGNTYLE (SEQ ID NO: 31); a CDR-L2 comprising KVSNRFS (SEQ ID NO: 24); and a CDR-L3 comprising FQGSHVPPT (SEQ ID NO: 25); or ii) the heavy chain variable (VH) region, comprising: X6YVX7H (SEQ ID NO: 49); 10 X 11 X 12KX 13 X 14 X 15 X 16 X 17 X 18 X 19 (SEQ ID NO: 50); and CDR-H2 comprising DFNYYVGAMDX 20 A VH region comprising a CDR-H3 comprising (SEQ ID NO:51); and A light chain variable (VL) region, 21 SX 22 QSLX 23 HSNGNTYX 24 CDR-L1 comprising H (SEQ ID NO: 52); 25 CDR-L2 containing VSNRFS (SEQ ID NO:53); and SQSX 26 X 27 X 28 VL region including CDR-L3 containing WT (SEQ ID NO: 54) Includes; X1~X 28 , optionally including any amino acid; X1 comprises a polar amino acid with an uncharged or positively charged side chain; X2 comprises a nonpolar amino acid with an aliphatic side chain; X3 comprises a polar amino acid with an uncharged or negatively charged side chain; X4 comprises a nonpolar amino acid with an aliphatic side chain; X5 comprises a polar amino acid with an uncharged side chain; X6 comprises a polar amino acid with a negative or uncharged side chain; X7 comprises a nonpolar amino acid with an aliphatic side chain; X8 comprises a nonpolar amino acid with an aliphatic or aromatic side chain; X9 comprises a polar amino acid with an uncharged side chain; 10 comprises a polar amino acid having a negatively charged side chain or a non-polar amino acid having an aliphatic side chain; 11 contains a non-polar amino acid having an aliphatic side chain or a polar amino acid having a positively charged side chain; 12 comprises a polar amino acid having an uncharged side chain or a non-polar amino acid having an aliphatic side chain; 13 contains a non-polar amino acid having an aromatic side chain; X 14 contains a polar amino acid having an uncharged side chain; X 15 contains a polar amino acid having a negatively charged side chain; X 16contains polar amino acids having positively charged or uncharged side chains; X 17 contains a non-polar amino acid having an aliphatic or aromatic side chain; X 18 contains polar amino acids having positively charged or uncharged side chains; X 19 comprises a polar amino acid having a negatively charged side chain or a non-polar amino acid having an aliphatic side chain; 20 contains a non-polar amino acid having an aromatic side chain; X 21 contains a polar amino acid having a positively charged side chain; X 22 contains a polar amino acid having an uncharged side chain; X 23 contains a non-polar amino acid having an aliphatic side chain; X 24 contains a non-polar amino acid having an aliphatic side chain; X 25 contains polar amino acids having positively charged or uncharged side chains; X 26 contains a polar amino acid having an uncharged side chain; X 27 contains a polar amino acid having a positively charged side chain or a non-polar amino acid having an aromatic side chain; 28 contains non-polar amino acids having aliphatic side chains, The agent according to any one of embodiments 1 to 3, comprising an anti-TREML antibody or an antigen-binding fragment thereof. 5. X1 is S or R; X2 is V or I; X3 is D or N; X4 is I or M; X5 is N or S; X6 is D, E or N; X7 is I or M; X8 is I, M or F; X9 is T or N; 10 is D or G; X 11 is G or H; X 12 is P, S or A; X 13 is Y or F; X 14 is S or N; X 15 is D or E; X 16 is K or T; X 17 is I, A or F; X 18 is K, R or T; X 19 is D or G; X 20 is F or Y; X 21 is R or K; X 22is S or T; X 23 is L, V or I; X 24 is L or V; X 25 is K or Q; X 26 is T or S; X 27 is H or Y; X 28 is I or V. 6. (i) a heavy chain variable (VH) region, comprising: a heavy chain complementarity determining region 1 (CDR-H1) comprising DYGMA (SEQ ID NO: 20); a CDR-H2 comprising FISNLAYSVYYADTVTG (SEQ ID NO: 21); and a CDR-H3 comprising EDYGDNGAIDY (SEQ ID NO: 22); and a light chain variable (VL) region, comprising: a light chain complementarity region 1 (CDR-L1) comprising RSSQNIVHSNGNTYLE (SEQ ID NO: 23); a CDR-L2 comprising KVSNRFS (SEQ ID NO: 24); and a CDR-L3 comprising FQGSHVPPT (SEQ ID NO: 25); (ii) a heavy chain variable (VH) region, comprising: a heavy chain complementarity determining region 1 (CDR-H1) comprising DYGMA (SEQ ID NO: 20); a CDR-H2 comprising FISNLAYSVYYADTVTG (SEQ ID NO: 21); and a CDR-H3 comprising EDYGDNGAIDY (SEQ ID NO: 22); and a light chain variable (VL) region, comprising: a light chain complementarity region 1 (CDR-L1) comprising RSSQSIVHSNGNTYLE (SEQ ID NO: 26); a CDR-L2 comprising KVSNRFS (SEQ ID NO: 24); and a CDR-L3 comprising FQGSHVPPT (SEQ ID NO: 25); (iii) a heavy chain variable (VH) region, comprising: a heavy chain complementarity determining region 1 (CDR-H1) comprising DYGMA (SEQ ID NO: 20); a CDR-H2 comprising FISNLAYRIYYADTVTG (SEQ ID NO: 27); and a CDR-H3 comprising EDYGNNGAMDY (SEQ ID NO: 28); and a light chain variable (VL) region, comprising: a light chain complementarity region 1 (CDR-L1) comprising RSSQSIVHSNGNTYLE (SEQ ID NO: 26); a CDR-L2 comprising KVSNRFS (SEQ ID NO: 24); and a CDR-L3 comprising FQGSHVPPT (SEQ ID NO: 25); (iv) a heavy chain variable (VH) region, comprising: CDR-H1 comprising DYVIH (SEQ ID NO: 32); CDR-H2 comprising YMNPYTDGPKYSDKIKD (SEQ ID NO: 33); and CDR-H3 comprising DFNYYVGAMDF (SEQ ID NO: 34); and a light chain variable (VL) region, comprising: CDR-L1 comprising RSSQSLLHSNGNTYLH (SEQ ID NO: 35); CDR-L2 comprising KVSNRFS (SEQ ID NO: 24); and CDR-L3 comprising SQSTHIWT (SEQ ID NO: 36); (v) a heavy chain variable (VH) region, comprising: CDR-H1 comprising DYVIH (SEQ ID NO: 32); CDR-H2 comprising YINPYTGGPKYSETARG (SEQ ID NO: 37); and CDR-H3 comprising DFNYYVGAMDF (SEQ ID NO: 34); and a light chain variable (VL) region, comprising: CDR-L1 comprising RSTQSLVHSNGNTYVH (SEQ ID NO: 38); CDR-L2 comprising KVSNRFS (SEQ ID NO: 24); and CDR-L3 comprising SQSTYVWT (SEQ ID NO: 56); (vi) a heavy chain variable (VH) region, comprising: CDR-H1 comprising EYVIH (SEQ ID NO: 39); CDR-H2 comprising YFNPYTGGSKFNEKFKD (SEQ ID NO: 40); and CDR-H3 comprising DFNYYVGAMDY (SEQ ID NO: 55); and a light chain variable (VL) region, comprising: CDR-L1 comprising RSSQSLVHSNGNTYLH (SEQ ID NO: 41); CDR-L2 comprising KVSNRFS (SEQ ID NO: 24); and CDR-L3 comprising SQSSHIWT (SEQ ID NO: 42); (vii) a heavy chain variable (VH) region, comprising: CDR-H1 comprising NYVMH (SEQ ID NO: 43); CDR-H2 comprising YFNPYNGHAKYSEKFTG (SEQ ID NO: 44); and CDR-H3 comprising DFNYYVGAMDY (SEQ ID NO: 55); and a light chain variable (VL) region, comprising: CDR-L1 comprising RSSQSLIHSNGNTYLH (SEQ ID NO: 45); CDR-L2 comprising QVSKRFS (SEQ ID NO: 46); and CDR-L3 comprising SQSTHIWT (SEQ ID NO: 36); or (viii) a heavy chain variable (VH) region, comprising: CDR-H1 comprising DYVIH (SEQ ID NO: 32); CDR-H2 comprising YINPYTGGPKYSETAKG (SEQ ID NO: 47); and CDR-H3 comprising DFNYYVGAMDF (SEQ ID NO: 34); and A light chain variable (VL) region comprising: CDR-L1 comprising KSTQSLVHSNGNTYVH (SEQ ID NO: 48); CDR-L2 comprising KVSNRFS (SEQ ID NO: 24); and CDR-L3 comprising SQSTYVWT (SEQ ID NO: 56). 6. The agent of any one of embodiments 1 to 5, comprising an anti-TREML antibody or an antigen-binding fragment thereof comprising: 7. (i) a VH region comprising SEQ ID NO:4, and a VL region comprising SEQ ID NO:5; (ii) a VH region comprising SEQ ID NO:6, and a VL region comprising SEQ ID NO:7; (iii) a VH region comprising SEQ ID NO:8, and a VL region comprising SEQ ID NO:9; (iv) a VH region comprising SEQ ID NO:10, and a VL region comprising SEQ ID NO:11; (v) a VH region comprising SEQ ID NO:12, and a VL region comprising SEQ ID NO:13; (vi) a VH region comprising SEQ ID NO:14, and a VL region comprising SEQ ID NO:15; (vii) a VH region comprising SEQ ID NO: 16, and a VL region comprising SEQ ID NO: 17; (viii) a VH region comprising SEQ ID NO: 18 and a VL region comprising SEQ ID NO: 19 7. The agent according to any one of embodiments 1 to 6, comprising: 8. A method for treating or alleviating one or more symptoms of a disease or condition associated with or characterized by immunosuppression in a subject in need thereof, comprising administering to the subject one or more agents described in any one of embodiments 1 to 7, and reversing the immunosuppression in the subject, thereby treating or alleviating one or more symptoms of the disease or condition. 9. The method of embodiment 8, wherein the step of reversing immunosuppression comprises inhibiting an inflammatory response, including inhibiting release of a cytokine such as IL-10 or inducing release of a cytokine such as TNF-α, or wherein the immunosuppression comprises inhibiting inflammation. 10. The method of embodiment 8 or 9, wherein the inflammatory response can be a monocyte-mediated, macrophage-mediated and / or neutrophil-mediated inflammatory response. 11. The method of any one of embodiments 8 to 10, wherein the disease or condition comprises malignant tumor growth, tumor angiogenesis, cancer, chronic infection, sepsis, immune exhaustion, or immunosenescence in aging. 12. Cancer is melanoma, lung cancer, squamous cell carcinoma of the lung, head and neck cancer, breast cancer, ovarian cancer, uterine cancer, prostate cancer, stomach cancer, cervical cancer, esophageal cancer, bladder cancer, kidney cancer, brain cancer, liver cancer, colon cancer, bone cancer, pancreatic cancer, skin cancer, cutaneous or intraocular malignant melanoma, ovarian cancer, rectal cancer, cancer of the anal region, stomach cancer, testicular cancer, cancer of the fallopian tubes, cancer of the endometrium, cancer of the cervix, cancer of the vagina, cancer of the vulva, Hodgkin's disease, non-Hodgkin's lymphoma, esophageal cancer, small intestine cancer, endocrine system cancer The method of any one of embodiments 8 to 11, comprising cancer, thyroid cancer, parathyroid cancer, adrenal cancer, sarcoma of soft tissue, urethral cancer, penile cancer, chronic or acute leukemia, solid tumors of childhood, lymphocytic lymphoma, cancer of the renal pelvis, neoplasms of the central nervous system (CNS), primary CNS lymphoma, spinal axis tumor, brain stem glioma, pituitary adenoma, Kaposi's sarcoma, epidermoid carcinoma, squamous cell carcinoma, T-cell lymphoma, and gastrointestinal cancer, optionally wherein the cancer comprises colon cancer. 13. The method of embodiment 12, wherein the chronic or acute leukemia is acute myeloid leukemia, chronic myelogenous leukemia, acute lymphoblastic leukemia, or chronic lymphocytic leukemia. 14. The method of any one of embodiments 8 to 12, wherein the method inhibits the proliferation of malignant tumor or cancer cells. 15. A method for inhibiting the binding of TREML1 to CD11b, comprising administering one or more agents described in any one of embodiments 1 to 7 to cells expressing CD11b and in the presence of TREML1, thereby inhibiting the binding of TREML1 to CD11b. 16. A method for reversing immunosuppression in a cell, comprising administering one or more agents described in any one of embodiments 1 to 7 to a cell that has been induced to become immunosuppressive by the I-domain of CD11b bound by TREML1. 17. A method for inhibiting PD-L1 expression on a cell, comprising administering one or more agents described in any one of embodiments 1 to 7 to a cell that has been induced to express PD-L1 by the I-domain of CD11b bound by TREML1. 18. The method of any one of embodiments 15 to 17, wherein the cells comprise immune cells. 19. The method of any one of embodiments 15 to 18, wherein the cell comprises a cell of the innate immune response system. 20. The method of any one of embodiments 15 to 19, wherein the cells comprise macrophages, neutrophils, monocytes, dendritic cells, natural killer cells, granulocytes, or a combination thereof. 21. The method of any one of embodiments 15 to 20, wherein the cell is present in a subject, and optionally the subject is a mammal. 22. A method according to any one of embodiments 15 to 21, for reversing cellular immunosuppression and / or treating a disease or condition associated with immunosuppression. 23. A method for diagnosing cancer or detecting the presence of a malignant tumor in a subject, comprising obtaining a biological sample from the subject and detecting TREML1 in the sample, thereby detecting cancer or tumor in the subject. 24. A method for determining whether a subject may be responsive to all treatments that may be administered as a form of cancer treatment, comprising the steps of obtaining a biological sample from the subject and detecting the presence of TREML1 in the sample, thereby determining whether the subject may be responsive to all treatments that may be administered as a form of cancer treatment. 25. The method of embodiment 23 or 24, further comprising quantifying the expression of TREML1 in the sample, and optionally further comprising comparing the expression of TREML1 in the subject with the expression of TREML1 in a control. In an embodiment, the control is a healthy subject. In an embodiment, the control is a reference value associated with the expression of TREML1 in healthy subjects. 26. The method of any one of embodiments 23 to 25, wherein the biological sample comprises a bodily fluid, cell or tissue, and optionally the bodily fluid comprises blood, urine, saliva, bile, bone marrow aspirate, breast milk, cerebrospinal fluid (CSF), plasma, serum, stool, vaginal fluid or synovial fluid; optionally the cell comprises a blood cell, an epithelial cell, a fibroblast, a liver cell, an immune cell (e.g., a T cell, a B cell, a NK cell, a monocyte, a macrophage, a dendritic cell, etc.), a stem cell, a peripheral blood cell or a stem cell; and optionally the tissue is tissue from a biopsied or resected tumor. 27. The method of any one of embodiments 23 to 26, wherein the step of detecting the presence of TREML1 comprises performing an immunological assay, a histological assay, a cytological assay, an enzyme-linked immunosorbent assay (ELISA), a bead-based detection assay, a DNA or RNA expression assay, or an aptamer-based assay. 28. The method of any one of embodiments 23 to 27, wherein the step of detecting the presence of TREML1 comprises using an agent of any one of embodiments 1 to 7 to detect the presence of TREML1. 29. The method of any one of embodiments 23 to 28, wherein the cancer or malignant tumor comprises a cancer as defined in embodiment 12 or 13. 30. The method of any one of embodiments 23 to 29, further comprising treating the subject with ICB therapy, optionally wherein the ICB therapy comprises administering atezolizumab, avelumab, or durvalumab to the subject. 31. The method of any one of embodiments 23 to 30, further comprising treating the subject by administering one or more agents of any one of embodiments 1 to 7. 32. A composition comprising one or more agents according to any one of embodiments 1 to 7, optionally further comprising a carrier. 33. The composition of embodiment 32, which is a pharmaceutical composition, optionally wherein the carrier is a pharma- ceutically acceptable carrier. 34. A kit comprising one or more agents according to any one of embodiments 1 to 7, or a pharmaceutical composition according to embodiment 33, for diagnosing cancer, detecting the presence of a malignant tumor, and / or determining whether a subject may be responsive to any treatment that may be administered as a form of cancer treatment. 35. A kit comprising one or more agents according to any one of embodiments 1 to 7, or a pharmaceutical composition according to embodiment 33, for treating a subject, optionally comprising a device for administering the agents to the subject. 36. The kit of embodiment 35, further comprising one or more treatments that can be administered as a form of cancer treatment, and optionally comprising means for administering to a subject one or more treatments that can be administered as a form of cancer treatment. EXAMPLES

[0096] Materials and Methods Cell culture and stable transfection Stable transfection of human or mouse TREML1 in HEK293 cells (BCRC) was performed using the jetPRIME (PolyPlus) transfection protocol. Briefly, HEK293 cells were cultured at 37°C in Dulbecco's Modified Eagle Medium (DMEM, Corning) supplemented with 10% heat-inactivated fetal bovine serum (Gibco) and 50 IU / mL penicillin and streptomycin (Corning). Cells were plated at 8x10 cells / well on 6-well plates (Coster). 5 The next day, a mixture of jetPRIME reagent and 2 μg of pcDNA 3.1 / human TREML1 (GenScript) or pcDNA 3.1 / mouse TREML1 (GenScript) expression plasmid with a neomycin resistance gene was added to the cells, and the cells were cultured for 24 hours. Then, the selection antibiotic G418 (InVivoGen) was added at a concentration of 1 mg / ml, and half of the culture medium containing the antibiotic was replaced every 2 to 3 days. After 3 weeks, human or mouse TREML1 expressing cells were collected using a Cell Sorter (SH800Z, SONY) to obtain human or mouse TREML1 highly expressing cells, which were seeded on 24-well plates (Coster) and 6-well plates at single cell / well and 5000 cells / well. The cells were maintained in DMEM medium containing 10% heat-inactivated fetal bovine serum, 50 IU / mL penicillin and streptomycin, and 1 mg / mL G418 at 37°C. After enrichment of the cells, human or mouse TREML1 expression was analyzed by flow cytometry with anti-human TREML1 / TLT-1 (MAB2394, R&D systems) or anti-mouse TREML1 / TLT-1 (MAB24241, R&D systems) antibodies. Finally, HEK293 / human TREML1 and HEK293 / mouse TREML1 stable clones were obtained.

[0097] Flow cytometry HEK293 / human TREML1 or HEK293 / mouse TREML1 were counted and washed twice with staining buffer (PBS containing 1% FBS and 0.1% sodium azide). Cells were cultured at 1x10 cells in staining buffer. 5 The cells were adjusted to a concentration of 100 μg / ml and treated with anti-TREML1 antibody or isotype control (MOPC21) at 10 μg / ml. The cells were then incubated at 37° C. for 30 minutes. After washing with staining buffer, the cells were treated with APC-conjugated anti-mouse IgG antibody for 15 minutes. After washing with staining buffer, the cells were analyzed by flow cytometry.

[0098] Solid-phase binding assay To investigate the TREML1 / CD11b I-domain interaction, recombinant CD11b I-domain (SEQ ID NO: 1) 5 μg / ml and BSA (negative control) proteins were coated separately on a 96-well plate and incubated overnight at 4°C. To avoid non-specific binding, blocking buffer (2% BSA in PBS) was added to the plate for 2 hours (hrs) at room temperature. Serially diluted TREML1 ECD was added and incubated for 2 hours at room temperature. Anti-TREML1 antibody (MAB2394, R&D systems) 1 μg / ml was added for 1 hour. Next, HRP-labeled secondary antibody, anti-rat IgG-HRP, was added to the plate and incubated for 30 minutes at room temperature. The plate was washed three times with 0.05% tween 20 PBS buffer (PBST) between each step. Finally, TMB substrate was added and incubated for 10-15 minutes to detect the HRP-labeled antibody. Afterwards, a stop solution of 1N HCL was added to stop the reaction. The absorbance at OD450 / 540 nm was measured by a microplate reader. To measure the half-maximal saturation binding of anti-TREML1 antibodies to TREML1, 5 μg / ml of human TREML1 ECD (SEQ ID NO: 2) or mouse TREML1 ECD (SEQ ID NO: 3) was coated on a 96-well plate and incubated overnight at 4°C. To avoid non-specific binding, blocking buffer (2% BSA in PBS) was added to the plate for 2 hours at room temperature. Serially diluted anti-TREML1 antibodies were added and incubated for 2 hours at room temperature. Then, HRP-labeled secondary antibody, anti-mouse IgG-HRP, was added to the plate and incubated for 30 minutes at room temperature. The plate was washed three times with 0.05% tween 20 PBS buffer (PBST) between each step. Finally, TMB substrate was added and incubated for 10-15 minutes to detect the HRP-labeled antibodies. Then, a stop solution of 1N HCL was added to stop the reaction. The absorbance at OD450 / 540 nm was measured by a microplate reader.

[0099] Preparation of human white blood cells (WBC) and human monocytes Peripheral blood samples were collected from healthy volunteer donors by venipuncture and collection into ACD tubes. Human white blood cells (WBCs) were isolated from peripheral blood using hypotonic red blood cell lysis in ammonium chloride containing ACK solution. Human monocytes were isolated from human peripheral blood mononuclear cells separated from white blood cells through Ficoll-Paque density gradient centrifugation. Selection was performed with a positive CD14 isolation kit (Miltenyi Biotec).

[0100] TREML1 Immunostaining Protocol and Scoring Human tumor tissue arrays were stained with anti-TREML1 antibody (26A6) at a concentration of 1 mg / ml (1:100, 60 min at room temperature), mouse probe DAB Brown (30 min at room temperature) and double stained CD68 macrophage marker (labeled in green) by Mouse / Rabbit Double Stain Kit (with DAB Brown / HRP Green) (BioTnA, TADS03) detection kit technology. Signal visualization was performed by diaminobenzidine (DAB) staining, and sections were counterstained with hematoxylin. TREML1 expression was scored by the positive percentage of the total area, and H-score indicated TREML1 intensity by calculating the sum of the percentages in all positive staining intensities.

[0101] TREML1 detection in vivo Anti-TREML1 (26A6) or isotype control (MOPC21) antibodies were labeled with VivoTag 680XL (PerkinElmer) according to the manufacturer's instructions. C57BL / 6 mice were subcutaneously injected with MC38 colon cancer cells. Tumor volumes of 300 mm 3 After 48 h incubation, 10 μg of VivoTag 680XL-conjugated anti-TREML1 antibody (26A6) and isotype control (MOPC21) were injected subcutaneously and imaged at various time points using IVIS Spectrum and FMT instruments. Images shown are 24 hours after injection of antibody conjugates.

[0102] Protocols for Cancer Treatment C57BL / 6 mice were inoculated with 3x10 MC38 cells. 5 Treatment was initiated 11 days after tumor inoculation. Tumor-bearing mice were treated intraperitoneally with anti-TREML1 antibody at 10 mg / kg twice a week. Mice were monitored and scored twice a week for the formation of palpable tumors, and tumors were scored when tumors reached 2,000 mm 3 Mice were killed if they exceeded a certain size. Tumor volumes were measured by calipers and calculated by the following formula: A×B×B×0.52 (A is the maximum diameter and B is the minimum diameter).

[0103] Example 1 The I-domain of CD11b is a receptor for TREML1, and blocking the interaction of TREML1 with CD11b can reverse TREML1-induced immune suppression. Soluble TREML1 was previously reported to directly bind to innate immune cells and induce the cells to express an immunosuppressive phenotype (WO2016197975A1). To screen for potential immunosuppressive receptors of TREML1 on monocyte membranes, recombinant histidine-tagged TREML1 ECD bound to a Ni-column was used. Monocyte lysates were then incubated with the TREML1 ECD-bound column. TREML1 ECD-bound complexes were eluted and then separated by SDS-PAGE. After trypsin digestion of the TREML1 ECD-bound complexes, the digested peptides were determined in LC-MS / MS. Interpretation of the MS / MS spectra was performed by the MASCOT database. According to the MASCOT likelihood analysis, some immunosuppressive receptors (e.g., CD11b, CD18, CD33 (Siglec-3), CD329 (Siglec-9) and HSP90b) have higher scores than other protein candidates. CD11b was selected for further study as a representative immunosuppressive receptor.

[0104] To examine whether soluble TREML1 binds to CD11b+ immune cells, the binding of TREML1 ECD to human monocytes and neutrophils in the presence of anti-CD11b antibody (ICRF44) was determined by flow cytometry. As shown in Figure 1, CD11b-specific antibodies can compete with TREML1 ECD for binding to monocytes and neutrophils expressing CD11b+ on the cell surface. Solid-phase binding studies showed that TREML1 ECD binds to the I-domain of CD11b in a concentration-dependent manner (Figure 2). Treatment with anti-CD11b antibody (ICRF44) normalized the level of HLA-DR expression. It reduced the level of PD-L1 expression on TREML1 ECD-treated monocytes (Figure 3). These results indicated that CD11b participates in immune suppression induced by TREML1. Blocking the interaction of CD11b with TREML1 can reverse the immune response induced by TREML1.

[0105] Example 2 The anti-TREML1 antibody specifically binds to the TREML1 ECD and blocks TREML1 ECD binding to CD11b+ immune cells. Several anti-TREML1 antibodies capable of binding to human and mouse TREML1 ECD were generated. As shown in FIG. 4, the anti-TREML1 antibodies bind to human and mouse TREML1 ECD in a concentration-dependent manner in solid-phase binding assays. The half-maximal saturation binding of the anti-TREML1 antibodies to human TREML1 ECD and mouse TREML1 ECD is shown in Table 4. The VH and VL regions of these TREML1 antibodies are listed in Table 3. These TREML1-binding antibodies (17E6, 25C6, and 26A6) exhibit high levels of paratope residue conservation across all CDR regions (Table 1). In contrast, CDR-H1, CDR-H3, CDR-L1 and CDR-L2 of (18D8, 23F10, 27D3, 28A9 and 29F4) appear to retain a greater level of germline conservation than CDR-H2 and CDR-L3 (Table 2). To examine whether these anti-TREML1 antibodies can bind to TREML1 on the cell surface, HEK293 cells that do not express endogenous TREML1 were transfected with pcDNA3.1 / human TREML1 and pcDNA3.1 / mouse TREML1 plasmids using liposome transfection. After G418 selection, several single cell clones stably expressing human and mouse TREML1 on the cell surface were obtained. Compared with the isotype control antibody (MOPC21), the anti-TREML1 antibodies (26A6, 23F10, 28A9 and 29F4) can bind to human TREML1 on HEK293 / human TREML1 (Figure 5, top). In addition, clones 26A6, 23F10 and 29F4 can further cross-react with mouse TREML1 on HEK293 / mouse TREML1 (Figure 5, bottom). To examine whether anti-TREML1 antibodies can block TREML1 ECD binding to CD11b+ immune cells, the binding of TREML1 ECD to human monocytes and neutrophils in the presence of anti-TREML1 antibodies was determined by flow cytometry. As shown in Figure 6, using TREML1-specific antibodies can reduce TREML1 ECD binding to neutrophils and monocytes expressing CD11b+ on the cell surface.

[0106] [Table 13]

[0107] Example 3 Treatment with anti-TREML1 antibodies could significantly reduce PD-L1 expression induced by TREML1 ECD. To examine whether anti-TREML1 antibodies could reverse TREML1 ECD-mediated cell suppression, human WBCs were treated with or without anti-TREML1 antibody (26A6) at 10 μg / ml in the presence of human TREML1 ECD at 1, 5, 10 μg / ml for 24 hours, and PD-L1 expression was analyzed by flow cytometry. As shown in Figure 7, PD-L1 expression in human monocytes was increased after 24 hours of incubation with TREML1 ECD at 1, 5, and 10 μg / ml, and was reduced in the presence of anti-TREML1 antibodies.

[0108] Example 4 TREML1 is enriched in the tumor microenvironment. To examine whether platelet-derived TREML1 is enriched in tumors, anti-TREML1 antibody (26A6) was used to detect TREML1 accumulation in human cancer biopsies. TREML1 expression in human tissues was examined by immunostaining in formalin-fixed paraffin-embedded tissues, and the intensity of TREML1 expression in the majority of human tumors was significantly higher than that in normal tissues (Figure 8A). The percentage of TREML-1-binding macrophages was quantified, and the fold change was calculated by dividing the percentage of TREML1 / CD68 double-positive cells in tumor tissues by the percentage in tumor-adjacent normal tissues (NAT). Since a percentage of 0 of TREML1 / CD68 double-positive cells was found in some normal tissues, including nose, breast, uterus, prostate, ovary, kidney, skin, esophagus, and stomach (indicated by an asterisk in Figure 8A), a percentage of 1 instead of 0 was used to calculate the fold change.

[0109] Since soluble TREML1 can be secreted by activated platelets and bind to immune cells, TREML1 (brown) can be found to colocalize with macrophages (green) and distribute around the tumor stromal area (Figure 8B). In Figure 8B, TREML1 (brown) can be found to colocalize with macrophages (green) and distribute around the tumor stromal area. Representative photographs of human gastric cancer tissue show sites of TREML1 and macrophage colocalization (indicated by arrows), and representative photographs of colon cancer show TREML1 in the tumor (indicated by asterisks).

[0110] To examine whether TREML1 was present in the tumor microenvironment of mice, mice were subcutaneously injected with MC38 colon cancer. VivoTag 680XL (PerkinElmer) conjugated with anti-TREML1 antibody (26A6) was used to detect TREML1 accumulation in vivo. Using IVIS images, TREML1 was observed to be highly enriched in MC38 colon cancer (Figure 9). Taken together, these data suggest that TREML1 is highly increased in the tumor microenvironment. TREML1 may serve as a prognostic marker and a potential target for cancer therapy.

[0111] Example 5 Treatment with anti-TREML1 antibodies can significantly reduce tumor growth. To examine the effect of TREML1 blockade on antitumor immunity, anti-TREML1 antibodies were tested as monotherapy in the MC38 colon cancer model. Mice were injected subcutaneously with MC38 colon cancer cells on day 0. Tumor volumes were approximately 30–100 mm. 3When tumors reached 60 days, mice were injected intraperitoneally (ip) with either control IgG (MOPC21; 10 mg / kg), anti-TREML1 (26A6; 10 mg / kg), or anti-TREML1 (23F10; 10 mg / kg) antibodies. Injections were repeated every 3-4 days. Efficacy was determined by monitoring tumor volume for each group. As shown in Figure 10, TREML1 blockade with anti-TREML1 antibodies potently delayed the subcutaneous growth of MC38 tumors.

[0112] Example 6 Identifying cancer patients for cancer treatment A biopsy is obtained from a patient diagnosed with cancer. Immunohistochemical staining is performed on the biopsy sample using an anti-TREML1 antibody. The intensity and percentage of staining is quantified and compared to staining in corresponding control (normal or healthy) tissue. Patients with elevated levels of TREML1 compared to controls are identified as candidates for cancer treatment.

[0113] The subject matter described above is provided for illustrative purposes only and should not be construed as limiting. Various modifications and variations can be made to the subject matter described herein without departing from the true spirit and scope of the present disclosure as set forth in the following claims, other than in accordance with the illustrated and described embodiments and examples of application.

[0114] All publications, patents, and patent applications cited in this specification are incorporated herein by reference in their entirety to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. While the above describes various embodiments, those skilled in the art will understand that various modifications, substitutions, omissions, and changes can be made without departing from the spirit thereof.

Claims

1. An agent that inhibits the binding of triggering receptor expressed by myeloid cells (TREM)-like transcript-1 (TREML1) to CD11b, wherein the agent is an antibody or an antigen-binding fragment thereof.

2. said CD11b is expressed on immune cells; or The agent according to claim 1, which is a polyclonal antibody, a monoclonal antibody, a humanized antibody, a chimeric antibody, a bispecific antibody, or an antigen-binding fragment thereof.

3. i) a heavy chain variable (VH) region, the heavy chain complementarity determining region 1 (CDR-H1) comprising DYGMA (SEQ ID NO: 20); FISNLAYX 1 X 2 CDR-H2 containing YYADTVTG (SEQ ID NO: 29); and EDYGX 3 NGAX 4 a VH region comprising a CDR-H3 comprising DY (SEQ ID NO: 30); and A light chain variable (VL) region comprising RSSQX 5 a VL region comprising: a light chain complementarity region 1 (CDR-L1) comprising IVHSNGNTYLE (SEQ ID NO: 31); a CDR-L2 comprising KVSNRFS (SEQ ID NO: 24); and a CDR-L3 comprising FQGSHVPPT (SEQ ID NO: 25); or ii) a heavy chain variable (VH) region comprising: X 6 YVX 7 CDR-H1 containing H (SEQ ID NO: 49);YX 8 NPYX 9 X 10 X 11 X 12 KX 13 X 14 X 15 X 16 X 17 X 18 X 19 CDR-H2 comprising (SEQ ID NO: 50); and DFNYYVGAMDX 20 a VH region comprising a CDR-H3 comprising (SEQ ID NO: 51); and A light chain variable (VL) region comprising: X 21 SX 22 QSLX 23 HSNGNTYX 24 CDR-L1 containing H (SEQ ID NO: 52);X 25 CDR-L2 containing VSNRFS (SEQ ID NO: 53); and SQSX 26 X 27 X 28 VL region containing CDR-L3 containing WT (SEQ ID NO: 54) Includes; X 1 ~X 28 is any amino acid; optionally, X 1 is a polar amino acid having an uncharged or positively charged side chain; X 2 is a nonpolar amino acid having an aliphatic side chain; X 3 is a polar amino acid having an uncharged or negatively charged side chain; X 4 is a nonpolar amino acid having an aliphatic side chain; X 5 is a polar amino acid with an uncharged side chain; X 6 is a polar amino acid having a negatively charged or uncharged side chain; X 7 is a nonpolar amino acid having an aliphatic side chain; X 8 is a nonpolar amino acid having an aliphatic or aromatic side chain; X 9 is a polar amino acid with an uncharged side chain; X 10 is a polar amino acid having a negatively charged side chain or a nonpolar amino acid having an aliphatic side chain; X 11 is a nonpolar amino acid having an aliphatic side chain or a polar amino acid having a positively charged side chain; X 12 is a polar amino acid with an uncharged side chain or a nonpolar amino acid with an aliphatic side chain; X 13 is a nonpolar amino acid having an aromatic side chain; X 14 is a polar amino acid with an uncharged side chain; X 15 is a polar amino acid with a negatively charged side chain; X 16 is a polar amino acid having a positively charged or uncharged side chain; X 17 is a nonpolar amino acid having an aliphatic or aromatic side chain; X 18 is a polar amino acid having a positively charged or uncharged side chain; X 19 is a polar amino acid having a negatively charged side chain or a nonpolar amino acid having an aliphatic side chain; X 20 is a nonpolar amino acid having an aromatic side chain; X 21 is a polar amino acid with a positively charged side chain; X 22 is a polar amino acid with an uncharged side chain; X 23 is a nonpolar amino acid having an aliphatic side chain; X 24 is a nonpolar amino acid having an aliphatic side chain; X 25 is a polar amino acid having a positively charged or uncharged side chain; X 26 is a polar amino acid with an uncharged side chain; X 27 is a polar amino acid with a positively charged side chain or a nonpolar amino acid with an aromatic side chain; X 28 is a nonpolar amino acid having an aliphatic side chain; and optionally X 1 is S or R; X 2 is V or I; X 3 is D or N; X 4 is I or M; X 5 is N or S; X 6 is D, E or N; X 7 is I or M; X 8 is I, M or F; X 9 is T or N; X 10 is D or G; X 11 is G or H; X 12 is P, S or A; X 13 is Y or F; X 14 is S or N; X 15 is D or E; X 16 is K or T; X 17 is I, A, or F; X 18 is K, R or T; X 19 is D or G; X 20 is F or Y; X 21 is R or K; X 22 is S or T; X 23 is L, V or I; X 24 is L or V; X 25 is K or Q; X 26 is T or S; X 27 is H or Y; X 28 The drug according to claim 1, wherein is I or V.

4. (i) a heavy chain variable (VH) region, the VH region comprising: a heavy chain complementarity determining region 1 (CDR-H1) comprising DYGMA (SEQ ID NO: 20); a CDR-H2 comprising FISNLAYRIYYADTVTG (SEQ ID NO: 27); and a CDR-H3 comprising EDYGNNGAMDY (SEQ ID NO: 28); and a light chain variable (VL) region, comprising: a light chain complementarity region 1 (CDR-L1) comprising RSSQSIVHSNGNTYLE (SEQ ID NO: 26); a CDR-L2 comprising KVSNRFS (SEQ ID NO: 24); and a CDR-L3 comprising FQGSHVPPT (SEQ ID NO: 25); (ii) a heavy chain variable (VH) region, comprising: a heavy chain complementarity-determining region 1 (CDR-H1) comprising DYGMA (SEQ ID NO: 20); a CDR-H2 comprising FISNLAYSVYYADTVTG (SEQ ID NO: 21); and a CDR-H3 comprising EDYGDNGAIDY (SEQ ID NO: 22); and a light chain variable (VL) region, comprising: a light chain complementarity region 1 (CDR-L1) comprising RSSQNIVHSNGNTYLE (SEQ ID NO: 23); a CDR-L2 comprising KVSNRFS (SEQ ID NO: 24); and a CDR-L3 comprising FQGSHVPPT (SEQ ID NO: 25); (iii) a heavy chain variable (VH) region, comprising: a heavy chain complementarity-determining region 1 (CDR-H1) comprising DYGMA (SEQ ID NO: 20); a CDR-H2 comprising FISNLAYSVYYADTVTG (SEQ ID NO: 21); and a CDR-H3 comprising EDYGDNGAIDY (SEQ ID NO: 22); and a light chain variable (VL) region, comprising: a light chain complementarity region 1 (CDR-L1) comprising RSSQSIVHSNGNTYLE (SEQ ID NO: 26); a CDR-L2 comprising KVSNRFS (SEQ ID NO: 24); and a CDR-L3 comprising FQGSHVPPT (SEQ ID NO: 25); (iv) a heavy chain variable (VH) region, comprising: CDR-H1 comprising DYVIH (SEQ ID NO: 32); CDR-H2 comprising YMNPYTDGPKYSDKIKD (SEQ ID NO: 33); and CDR-H3 comprising DFNYYVGAMDF (SEQ ID NO: 34); and a light chain variable (VL) region, comprising: CDR-L1 comprising RSSQSLLHSNGNTYLH (SEQ ID NO: 35); CDR-L2 comprising KVSNRFS (SEQ ID NO: 24); and CDR-L3 comprising SQSTHIWT (SEQ ID NO: 36); (v) a heavy chain variable (VH) region, comprising: CDR-H1 comprising DYVIH (SEQ ID NO: 32); CDR-H2 comprising YINPYTGGPKYSETARG (SEQ ID NO: 37); and CDR-H3 comprising DFNYYVGAMDF (SEQ ID NO: 34); and a light chain variable (VL) region, comprising: CDR-L1 comprising RSTQSLVHSNGNTYVH (SEQ ID NO: 38); CDR-L2 comprising KVSNRFS (SEQ ID NO: 24); and CDR-L3 comprising SQSTYVWT (SEQ ID NO: 56); (vi) a heavy chain variable (VH) region, comprising: CDR-H1 comprising EYVIH (SEQ ID NO: 39); CDR-H2 comprising YFNPYTGGSKFNEKFKD (SEQ ID NO: 40); and CDR-H3 comprising DFNYYVGAMDY (SEQ ID NO: 55); and a light chain variable (VL) region, comprising: CDR-L1 comprising RSSQSLVHSNGNTYLH (SEQ ID NO: 41); CDR-L2 comprising KVSNRFS (SEQ ID NO: 24); and CDR-L3 comprising SQSSHIWT (SEQ ID NO: 42); (vii) a heavy chain variable (VH) region, comprising: CDR-H1 comprising NYVMH (SEQ ID NO: 43); CDR-H2 comprising YFNPYNGHAKYSEKFTG (SEQ ID NO: 44); and CDR-H3 comprising DFNYYVGAMDY (SEQ ID NO: 55); and a light chain variable (VL) region, comprising: CDR-L1 comprising RSSQSLIHSNGNTYLH (SEQ ID NO: 45); CDR-L2 comprising QVSKRFS (SEQ ID NO: 46); and CDR-L3 comprising SQSTHIWT (SEQ ID NO: 36); or (viii) a heavy chain variable (VH) region, comprising: CDR-H1 comprising DYVIH (SEQ ID NO: 32); CDR-H2 comprising YINPYTGGPKYSETAKG (SEQ ID NO: 47); and CDR-H3 comprising DFNYYVGAMDF (SEQ ID NO: 34); and a light chain variable (VL) region comprising: CDR-L1 comprising KSTQSLVHSNGNTYVH (SEQ ID NO: 48); CDR-L2 comprising KVSNRFS (SEQ ID NO: 24); and CDR-L3 comprising SQSTYVWT (SEQ ID NO: 56). The agent of claim 1, comprising an anti-TREML antibody or an antigen-binding fragment thereof comprising:

5. (i) a VH region comprising SEQ ID NO: 8 and a VL region comprising SEQ ID NO: 9; (ii) a VH region comprising SEQ ID NO: 6 and a VL region comprising SEQ ID NO: 7; (iii) a VH region comprising SEQ ID NO: 4 and a VL region comprising SEQ ID NO: 5; (iv) a VH region comprising SEQ ID NO: 10 and a VL region comprising SEQ ID NO: 11; (v) a VH region comprising SEQ ID NO: 12 and a VL region comprising SEQ ID NO: 13; (vi) a VH region comprising SEQ ID NO: 14 and a VL region comprising SEQ ID NO: 15; (vii) a VH region comprising SEQ ID NO: 16 and a VL region comprising SEQ ID NO: 17; or (viii) a VH region comprising SEQ ID NO: 18 and a VL region comprising SEQ ID NO: 19 The drug of claim 1, comprising:

6. The agent of claim 1 for use as a medicine.

7. A drug as described in claim 1 for use in treating or alleviating one or more symptoms of a disease or condition associated with or characterized by immunosuppression in a subject, and reversing immunosuppression in said subject, thereby treating or alleviating one or more symptoms of said disease or condition.

8. reversing immunosuppression includes inhibiting inflammation; or the inflammatory response comprises a monocyte-mediated, macrophage-mediated and / or neutrophil-mediated inflammatory response; or The disease or condition comprises malignant tumor growth, tumor angiogenesis, cancer, chronic infection, sepsis, immune exhaustion, or immunosenescence in aging, and optionally The cancer is selected from the group consisting of melanoma, lung cancer, squamous cell carcinoma of the lung, head and neck cancer, breast cancer, ovarian cancer, uterine cancer, prostate cancer, stomach cancer, cervical cancer, esophageal cancer, bladder cancer, kidney cancer, brain cancer, liver cancer, colon cancer, bone cancer, pancreatic cancer, skin cancer, cutaneous or intraocular malignant melanoma, ovarian cancer, rectal cancer, cancer of the anal region, stomach cancer, testicular cancer, cancer of the fallopian tubes, cancer of the endometrium, cancer of the cervix, cancer of the vagina, cancer of the vulva, Hodgkin's disease, non-Hodgkin's disease cancer of the esophagus, cancer of the small intestine, cancer of the endocrine system, cancer of the thyroid gland, cancer of the parathyroid gland, cancer of the adrenal gland, sarcoma of soft tissue, cancer of the urethra, cancer of the penis, chronic or acute leukemia, solid tumors of childhood, lymphocytic lymphoma, cancer of the renal pelvis, neoplasms of the central nervous system (CNS), primary CNS lymphoma, tumors of the spinal axis, brainstem glioma, pituitary adenoma, Kaposi's sarcoma, epidermoid carcinoma, squamous cell carcinoma, T-cell lymphoma, and cancer of the gastrointestinal tract, and in some cases The drug of claim 1, wherein the chronic or acute leukemia is acute myeloid leukemia, chronic myelogenous leukemia, acute lymphoblastic leukemia, or chronic lymphocytic leukemia.

9. A drug described in claim 1 for use in a method for inhibiting the binding of TREML1 to CD11b, the method comprising a step of administering the drug described in claim 1 to cells that express CD11b and are in the presence of TREML1, thereby inhibiting the binding of TREML1 to CD11b.

10. A drug described in claim 1 for use in a method for reversing immunosuppression in cells, the method comprising a step of administering the drug described in claim 1 to cells that have been induced to become immunosuppressive by the I-domain of CD11b bound by TREML1.

11. 10. The agent of claim 1 for use in a method for inhibiting PD-L1 expression on a cell, the method comprising administering the agent of claim 1 to a cell that has been induced to express PD-L1 by the I-domain of CD11b bound by TREML1.

12. 12. The agent according to any one of claims 9 to 11, wherein the cells comprise immune cells, and optionally The cells include cells of the innate immune response system, and optionally The agent wherein said cells include macrophages, neutrophils, monocytes, dendritic cells, natural killer cells and granulocytes.

13. 10. The agent of claim 1 for use in a method for diagnosing cancer or detecting the presence of a malignant tumor in a subject and / or determining whether the subject may be responsive to one or more cancer treatments, the method comprising obtaining a biological sample from the subject and detecting TREML1 in the sample, thereby detecting cancer or a tumor in the subject.

14. The drug described in claim 13, wherein the method further comprises a step of quantifying the expression of TREML1 in the sample, and optionally a step of comparing the expression of TREML1 in the subject with the expression of TREML1 in a control.

15. the biological sample comprises a bodily fluid, cell or tissue, optionally wherein the bodily fluid comprises blood, urine, saliva, bile, bone marrow aspirate, breast milk, cerebrospinal fluid (CSF), plasma, serum, stool, vaginal fluid or synovial fluid; optionally wherein the cell comprises a blood cell, epithelial cell, fibroblast, hepatocyte, immune cell, stem cell, peripheral blood cell or stem cell; optionally wherein the tissue is tissue from a biopsied or resected tumor; or the step of detecting the presence of TREML1 comprises performing an immunological assay, a histological assay, a cytological assay, an enzyme-linked immunosorbent assay (ELISA), a bead-based detection assay, a DNA or RNA expression assay, or an aptamer-based assay; or Detecting the presence of TREML1 comprises using one or more agents of claim 1 to detect the presence of TREML1, and optionally The cancer is melanoma, lung cancer, squamous cell carcinoma of the lung, head and neck cancer, breast cancer, ovarian cancer, uterine cancer, prostate cancer, stomach cancer, cervical cancer, esophageal cancer, bladder cancer, kidney cancer, brain cancer, liver cancer, colon cancer, bone cancer, pancreatic cancer, skin cancer, cutaneous or intraocular malignant melanoma, ovarian cancer, rectal cancer, cancer of the anal region, stomach cancer, testicular cancer, cancer of the fallopian tubes, cancer of the endometrium, cancer of the cervix, cancer of the vagina, cancer of the vulva, Hodgkin's disease, non-Hodgkin's lymphoma, esophageal cancer, small intestine cancer, endometrial cancer, 15. The method of claim 13 or 14, comprising cancers of the endocrine system, thyroid cancer, parathyroid cancer, adrenal cancer, sarcoma of soft tissue, urethral cancer, penile cancer, chronic or acute leukemia, solid tumors of childhood, lymphocytic lymphoma, cancer of the renal pelvis, neoplasms of the central nervous system (CNS), primary CNS lymphoma, spinal axis tumor, brainstem glioma, pituitary adenoma, Kaposi's sarcoma, epidermoid carcinoma, squamous cell carcinoma, T-cell lymphoma, and gastrointestinal cancer, optionally wherein the cancer comprises colon cancer.

16. A pharmaceutical composition comprising the agent of any one of claims 1 to 6.

17. An in vitro method for inhibiting the binding of TREML1 to CD11b, comprising the step of administering the agent described in claim 1 to cells that express CD11b and are in the presence of TREML1, thereby inhibiting the binding of TREML1 to CD11b.

18. An in vitro method for reversing immunosuppression in cells, comprising the step of administering the agent described in claim 1 to cells that have been induced to become immunosuppressive by the I-domain of CD11b bound to TREML1.

19. An in vitro method for inhibiting PD-L1 expression on cells, comprising administering the agent of claim 1 to cells that have been induced to express PD-L1 by the I-domain of CD11b bound by TREML1.

20. 20. The in vitro method according to any one of claims 17 to 19, wherein the cells comprise immune cells, optionally comprising The cells include cells of the innate immune response system, and optionally The in vitro method, wherein the cells include macrophages, neutrophils, monocytes, dendritic cells, natural killer cells and granulocytes.

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