Anti-TREM1 antibodies and methods of use thereof

Abstract

To provide antagonistic antibodies to block the TREM1 function that can be used to treat multiple inflammatory disorders where excessive myeloid cell activation or survival is pathogenic, such as sepsis, rheumatoid arthritis or osteoarthritis, Crohn's disease, inflammatory bowel disease, ulcerative colitis, multiple sclerosis, or others.SOLUTION: The present disclosure generally provides: compositions that include antibodies, e.g., monoclonal, chimeric, and humanized antibodies, antibody fragments, etc., and that specifically bind to a TREM1 protein, e.g., mammalian TREM1 or human TREM1; and use of such compositions in preventing or reducing the risk of, or treating, an individual in need thereof.SELECTED DRAWING: Figure 6D

Description

[Technical Field]

[0001] Cross-reference to related applications This application claims the benefit of U.S. Provisional Patent Application No. 62 / 304,018, filed March 4, 2016, which is incorporated by reference for all purposes. [Background technology]

[0002] The innate immune system consists of a diverse set of cell types, including neutrophils, tissue macrophages, monocytes, dendritic cells, and CNS microglia. These cells are best known for their role as a relatively primitive immune system compared to adaptive immune cells, T and B cells. Innate immune cells, particularly neutrophils, are usually the first to arrive at sites of infection or inflammation. Another important aspect of innate immune cells, such as tissue macrophages, dendritic cells, and CNS microglia, is that they act as sentinels against pathogens and danger and secondarily recruit additional innate immune cells, such as neutrophils, as well as adaptive immune cells. A third critical function of innate immune system cells, particularly dendritic cells, is to regulate the adaptive immune system, in part as professional antigen-presenting cells and in part through mediators, including cytokines and chemokines. Innate immune cells also play an important role through these factors and cell surface signals in dividing tissues toward repair and healing or toward inflammation and destruction. Innate immune cells such as macrophages are often described as polarized toward either an M1-like pro-inflammatory or an M2-like pro-repair phenotype, but it is increasingly recognized that these cells exhibit a greater degree of diversity.

[0003] Innate immune cells express numerous cell surface receptors and intracellular sensory molecules that enable self-recognition of pathogen- or danger-associated molecular patterns (PAMPs or DAMPs) and, if necessary, the initiation of inflammatory and antimicrobial responses. A family of evolutionarily conserved innate immune receptors, the so-called triggering receptors expressed on myeloid cells (TREMs), has been identified and characterized. TREMs belong to the immunoglobulin (Ig) superfamily of receptors and contain both inhibitory and activating receptor family members (Allcock, Barrow, et al., European Journal of Immunology, pp. 567-577; 2003) (Ford and McVicar, Current Opinion in Immunology, pp. 38-46; 2009) (Klesney-Tait, Turnbull, et al., Nat Immunol, pp. 1266-1273; 2006). In contrast to the fairly ubiquitously expressed TLRs and NOD-like receptors, TREM expression appears restricted to cells of the myeloid lineage (Bouchon, Dietrich, et al., J Immunol, pp. 4991-4995; 2000). Furthermore, TREMs appear to act primarily as fine-tuners, rather than initiators, of the inflammatory response, based on their ability to integrate and potently regulate TLR- and NOD-induced signals (Arts, Joosten, et al., Journal of Leukocyte Biology, pp. 209-215; 2012).

[0004] Triggering receptor-1 expressed on myeloid cells (TREM-1, also referred to herein as TREM1) is the first identified and best characterized receptor of the TREM family and has a primarily activating function (Weber, Schuster, et al., PLoS Pathog, e1003900; 2014). TREM-1 consists of an ectodomain composed of a single Ig V-type domain, a transmembrane region, and a short cytoplasmic tail that recruits DNAX-activating protein 12 (DAP12) for signal transduction (Bouchon, Dietrich, et al., J Immunol, pp. 4991-4995; 2000; Bouchon, Facchetti, et al., Nature, pp. 1103-1107; 2001). TREM-1 is constitutively expressed in neutrophils and in subsets of monocytes and macrophages, and TREM-1 expression is further upregulated upon exposure of cells to microbial products (Bouchon, Dietrich, et al., J Immunol, pp. 4991-4995; 2000; Bouchon, Facchetti, et al., Nature, pp. 1103-1107; 2001). Immunol, pp. 4991-4995; 2000). Whereas cross-linking of TREM-1 with agonist antibodies alone induces only modest cellular activation, TREM-1 potently cooperates with its respective TLR ligands to substantially amplify the oxidative burst and generate proinflammatory mediators such as TNF, IL-1β, IL-6, IL-8, MCP-1, and Mip-1α (Bouchon, Dietrich, et al., J Immunol, pp. 4991-4995; 2000) (Bouchon, Facchetti, et al., Nature, pp. 1103-1107; 2001) (Radsak, Salih, et al., The Journal of Immunology, pp. 4956-4963; 2004). Human genetic evidence and disease model studies, as detailed below, specifically link TREM-1 to human disease.

[0005] In vivo, the role of TREM-1 has been largely characterized in experimental models of endotoxin-induced shock or microbial sepsis, in which blockade of TREM-1 signaling conferred considerable protection (Bouchon, Facchetti, et al., Nature, pp. 1103-1107; 2001) (Gibot, Journal of Experimental Medicine, pp. 1419-1426; 2004; Gibot, Annals of Internal Medicine, 9; 2004). Soluble forms of the TREM-1 molecule, a small putative peptide blocker (LP17), or siRNA that inhibits TREM-1 expression have all been used in animal studies to reduce TREM-1 signaling. All three methods applied to study lipopolysaccharide-induced endotoxemia were reported to reduce TREM-1 signaling and systemic cytokine production, resulting in improved animal survival (Wu, Li et al., Cancer Research, pp. 3977-3986; 2012) (Gibot, Journal of Experimental Medicine, pp. 1419-1426; 2004) (Bouchon, Facchetti et al., Nature, pp. 1103-1107; 2001).

[0006] To investigate the role of TREM-1 in inflammation, homeostasis, and disease, Weber et al. (Weber, Schuster, et al., PLoS Pathog, e1003900; 2014) demonstrated TREM-1 deficiency by targeted deletion of exon 2 (TREM1 - / -(2014) mice. Using models of inflammation and infection ranging from experimental colitis to infection with Leishmania major, influenza virus, and Legionella pneumophila, they show that the complete absence of TREM-1 significantly attenuates morbidity and immune-mediated pathology, while microbial control remains intact in the models tested. These findings demonstrate a clear role for TREM-1 in chronic inflammatory disorders and suggest a limited role in infection. However, these findings are refuted by other published studies showing defects in specific forms of microbial control, including through the formation of neutrophil extracellular traps (NETs) (Barletta, Cagnina, et al., American Journal of Respiratory and Critical Care Medicine, pp. 1044–1050; 2012) (Lin, Tseng, et al., Infect Immun, pp. 1335–1342; 2014).

[0007] TREM-1 may also play a role in non-infectious inflammatory conditions. Thus, TREM-1 expression can also be induced by the non-microbial agent, monosodium urate monohydrate crystals (MSU), as seen in gauze or by hypoxic cell culture conditions in vitro (Bosco, Pierobon et al., Blood, pp. 2625-2639; 2010) (Murakami, Akahoshi et al., Arthritis & Rheumatism, pp. 455-462; 2006). Increased TREM-1 levels have been reported in patients with rheumatoid arthritis, acute pancreatitis, chronic obstructive pulmonary disease, and cardiac arrest (Radsak, Taube, et al., Clinical and Developmental Immunology, pp. 1-7; 2007) and Yasuda, 2008, no. 29 (Adib-Conquy, Monchi, et al., Shock, pp. 406-410; 2007; Collins, La, et al., Annals of the Rheumatic Diseases, pp. 1768-1774; 2008). Furthermore, Weber et al. (Weber, Saurer et al., European Journal of Immunology, p773-779; 2011) described the involvement of TREM-1 in human inflammatory bowel disease (IBD) and in animal models of colitis (Schenk, Bouchon et al., Journal of Clinical Investigation, p3097-3106; 2007; Weber, Saurer et al., European Journal of Immunology, p773-779; 2011; Saurer, Rihs et al., Journal of Crohn's and Colitis, p913-923; 2012).

[0008] Studies addressing the influence of TREM-1 in disease have so far mostly relied on the use of TREM-1 / Ig fusion proteins or synthetic peptides mimicking portions of the extracellular domain of TREM-1 as competitive inhibitors of the pathway. These inhibitors have been reported to confer protection from endotoxin-induced shock, microbial sepsis, and experimental colitis in animal models (Schenk, Bouchon, et al., Journal of Clinical Investigation, pp. 3097-3106; 2007) (Bouchon, Facchetti, et al., Nature, pp. 1103-1107; 2001). However, some findings regarding the impact of TREM-1 inhibitors on microbial control appear to be controversial (Klesney-Tait, Keck et al., Journal of Clinical Investigation, pp. 138-149; 2012) (Gibot, Massin et al., European Journal of Immunology, pp. 456-466; 2007) (Gibot, Alauzet et al., The Journal of Infectious Diseases, pp. 975-983; 2006) (Bouchon, Facchetti et al., Nature, pp. 1103-1107; 2001).

[0009] Investigations into the precise physiological function and disease role of TREM-1 have often been limited by the lack of a definitive substrate: putative TREM-1 ligands have been described on the surface of human platelets and mouse granulocytes during experimental peritonitis and endotoxemia (Haselmayer, Grosse-Hovest, et al., Blood, pp. 1029-1035; 2007; Zanzinger, Schellack, et al., Immunology, pp. 185-195; 2009) (Gibot, Alauzet, et al., The Journal of Infectious Diseases, pp. 975-983; 2006). Furthermore, necrotic cell lysates also appear to stimulate a pro-inflammatory response in a TREM-1-dependent manner, which may be associated with association with High Mobility Group Box 1 (HMGB1) protein (El Mezayen, El Gazzar et al., Immunology Letters, p36-44; 2007) (Wu, Li et al., Cancer Res, p3977-3986; 2012).

[0010] Substances released by necrotic cells that are thought to induce inflammatory signaling cascades and cytokine / chemokine production by myeloid cells include potential TREM-1 ligands, such as high-mobility group box 1 (HMGB1) and heat shock protein 70 (HSP70) (El Mezayen, El Gazzar, et al., Immunology Letters, pp. 36-44; 2007). The binding between TREM-1 and HMGB1 molecules was analyzed by SPR (Wu, Li, et al., Cancer Res, pp. 3977-3986; 2012). BIAcore sensograms of the two proteins showed a rapid increase in response units (RU), indicating binding of these proteins to immobilized HMGB1 on a chip, followed by a decrease in RU due to loss of bound molecules upon washing (Wu, Li, et al., Cancer Research, pp. 3977-3986; 2012). The binding of RAGE and TREM-1 to HMGB1 was concentration-dependent. The affinity constants, Kd, ​​were determined by SPR technology and found to be 0.2 mmol / L for RAGE and HMGB1, and 35.4 mmol / L for TREM-1 and HMGB1, respectively (Wu, Li et al., Cancer Research, p3977-3986; 2012). Therefore, binding with this potential ligand appears to be of relatively low affinity.

[0011] Another molecular ligand involved in TREM-1 signaling was described by Read et al. (Read, Kuijper et al., J Immunol, pp. 1417-1421; 2015) based on previous work by Gibot et al. (Gibot, Buonsanti et al., Infect Immun, pp. 2823-2830; 2006), which suggested that endogenous ligands for TREM-1 are present on neutrophils activated by bacteria or TLR ligands (TLRs). The relationship between cancer and inflammation appears to be multifaceted. Thus, inflammation can promote tumor initiation, but it can also promote antitumor checkpoint immune responses against established tumors. While some innate immune myeloid cells are thought to support tumor growth when polarized toward an anti-inflammatory phenotype, such as myeloid-derived suppressor cells, other myeloid cells, such as dendritic cells, play a critical role in presenting tumor antigens to T cells in the context of cytotoxic T lymphocyte (CTL)-mediated antitumor immune responses. Experimental and clinical evidence suggests that chronic inflammation can promote multiple aspects of carcinogenesis, acting as a tumor promoter by establishing a tissue microenvironment favorable for the initial genetic alterations that give rise to tumor cells, allowing tumors to progress and metastasize (Wu, Wu, Li, et al., Cancer Research, pp. 3977-3986; 2012) (Trinchieri, F1000 Med Rep., 2011; Trinchieri, Annual Review of Immunology, pp. 677-706; 2012) (Borrello, Degl'Innocenti, et al., Cancer Letters, pp. 262-270; 2008) (Kuraishy, ​​Karin, et al., Immunity, pp. 467-477; 2011). Deletion of the mouse homolog of TREM1 in mice attenuated hepatocellular carcinogenesis caused by diethylnitrosamine (DEN). A single injection of DEN into 2-week-old wild-type male mice resulted in the induction of alpha-fetoprotein (AFP)-expressing hepatocellular carcinoma (HCC) within 8 months (Wu, Li et al., Cancer Research, p3977-3986; 2012), many of which were large and accompanied by obvious neovascularization.Unlike WT mice, TREM1- / - male mice treated with DEN at the same age were tumor-free at 8 months. At 14 months, only 4% of TREM1- / - mice developed small HCCs, whereas all WT mice developed multiple conventional HCCs at that time (Wu, Li et al., Cancer Research, p3977-3986; 2012). These data indicate that efficient HCC induction in response to DEN requires TREM1.

[0012] TREM-1 was found to be essential for the initiation of DEN-induced liver injury, and TREM1-deficient mice showed less liver damage than WT mice during the early stages of HCC development. Collectively, the data suggest that TREM1 plays a role in the DEN-mediated inflammatory activation of Kupffer cells, which normally leads to tumorigenesis (Wu, Li, et al., Cancer Research, pp. 3977-3986; 2012). Cancer cells can directly upregulate TREM-1 expression in patient macrophages, and TREM-1 expression in tumor-associated macrophages has been shown to be associated with cancer recurrence and poor survival in patients with non-small cell lung cancer (Ho, Liao, et al., Am J Respir Crit Care Med, pp. 763-770; 2008). Yuan et al. (Yuan, Mehta et al., PLoS One, e94241; 2014) describe a TREM1 antibody (U.S. Patent No. 9000127 B2) (Arts, Joosten et al., Eur Cytokine Netw, p11-14; 2011). However, no agonist antibodies that activate TREM1 in solution and / or antibodies that cooperate with TREM1 ligands have been described. Such antibodies could be used to treat cancers where increased myeloid cell promotion of inflammatory polarization is expected to be beneficial, as well as diseases such as frontotemporal dementia and Alzheimer's disease, where insufficient TREM1 and / or DAP12 signaling is associated.

[0013] Furthermore, no antagonist antibodies have been reported that block TREM1 function noncompetitively, independently of ligand blockade, or by binding to multiple sites on TREM1. Such antibodies could be used to treat multiple inflammatory disorders in which excessive myeloid cell activation or survival is pathogenic, such as sepsis, rheumatoid arthritis or osteoarthritis, Crohn's disease, inflammatory bowel disease, ulcerative colitis, multiple sclerosis, and others. Furthermore, neurodegenerative diseases at the inflammatory stage are predicted to paradoxically benefit from reduced TREM-1 signaling, despite the protective role of TREM-1. Finally, in some contexts, such as with TREM-1-expressing tumors or cells infiltrated by myeloid-derived suppressor cells, TREM-1 blockade may be protective by reducing tumor survival and enhancing antitumor immunity.

[0014] All references cited herein, including patent applications and publications, are hereby incorporated by reference in their entirety. Summary of the Invention

[0015] This section provides a summary of certain aspects of the present disclosure. The present invention is not limited to the specific aspects or specific implementations described in this summary.

[0016] The present disclosure is generally directed to compositions comprising antibodies, e.g., monoclonal, chimeric, humanized antibodies, antibody fragments, etc., that specifically bind to a TREM1 protein, e.g., mammalian TREM1 or human TREM1, and methods of using such compositions. Antibodies of the present disclosure may include agonist, antagonist, or inactive antibodies. The methods provided herein find use in preventing, reducing the risk of having, or treating individuals with a disorder or disease described herein. The methods provided herein also find use in inducing or promoting the survival, maturation, functionality, migration, or proliferation of one or more immune cells in an individual in need thereof. The methods provided herein further find use in reducing the activity, functionality, or survival of regulatory T cells, tumor-embedded immune suppressor dendritic cells, tumor-embedded immune suppressor macrophages, neutrophils, natural killer (NK) cells, myeloid-derived suppressor cells, tumor-associated macrophages, NK cells, acute myeloid leukemia (AML) cells, chronic lymphocytic leukemia (CLL) cells, or chronic myeloid leukemia (CML) cells in an individual in need thereof.

[0017] In instances where tumor cells, such as AML cells, express TREM1, the anti-TREM1 antibodies of the present disclosure also find use in treating cancer. In some embodiments, anti-TREM1 antibodies and / or TREM1 antibody-drug conjugates, including antibodies that exhibit antibody-dependent cell-mediated cytotoxicity (ADCC), may be used to target and inhibit cancers such as AML.

[0018] One class of anti-TREM1 antibodies of the present disclosure relates to agonistic antibodies that induce one or more TREM1 activities, for example, on human primary immune cells and TREM1-expressing cell lines. In some embodiments, the anti-TREM1 antibodies of the present disclosure, when combined with one or more TREM1 ligands, enhance one or more TREM1 activities induced by binding of one or more TREM1 ligands to the TREM1 protein. In some embodiments, such agonistic anti-TREM1 antibodies advantageously can enhance ligand-induced TREM1 activities without competing with or otherwise blocking binding of one or more TREM1 ligands to the TREM1 protein. In some embodiments, agonistic antibodies can activate and / or enhance one or more TREM1 activities regardless of whether the antibody is clustered or in solution. In some embodiments, agonistic antibodies can activate TREM1 in solution without the need for clustering by a secondary antibody, an Fc receptor, or binding to a plate. In some embodiments, agonist antibodies can activate TREM1 at therapeutic sites of action in vivo, regardless of the presence or absence of an antibody clustering mechanism. In some embodiments, agonist antibodies can ensure that TREM1-expressing immune cells act primarily in the location where they are needed for therapeutic efficacy, available to interact with their physiological targets. In some embodiments, agonist antibodies do not block TREM1 activity, which leads to an increased risk of disease similar to that observed with genetic mutations that reduce TREM1 activity.

[0019] In certain aspects, the disclosure relates to an isolated antibody that binds to a TREM1 protein, wherein the antibody induces one or more TREM1 activities. In some embodiments, the antibody enhances one or more TREM1 activities induced by binding of one or more TREM1 ligands to a TREM1 protein compared to the one or more TREM1 activities induced by binding of the one or more TREM1 ligands to the TREM1 protein in the absence of the isolated antibody. In some embodiments that may be combined with any of the preceding embodiments, the antibody enhances one or more TREM1 activities without blocking binding of the one or more TREM1 ligands to the TREM1 protein. In some embodiments that may be combined with any of the preceding embodiments, the antibody does not compete with one or more TREM1 ligands for binding to the TREM1 protein. In some embodiments that may be combined with any of the preceding embodiments, the antibody enhances binding of one or more TREM1 ligands to the TREM1 protein.

[0020] In some embodiments that may be combined with any of the preceding embodiments, the antibody competes with one or more TREM1 ligands for binding to the TREM1 protein. In some embodiments that may be combined with any of the preceding embodiments, the antibody induces one or more TREM1 activities as described herein and enhances one or more TREM1 activities induced by binding of one or more TREM1 ligands to the TREM1 protein.

[0021] In some embodiments that may be combined with any of the preceding embodiments, the antibody cooperates with one or more TREM1 ligands to enhance one or more TREM1 activities as described herein. In some embodiments that may be combined with any of the preceding embodiments, the antibody enhances one or more TREM1 activities in the absence of cell surface clustering of TREM1. In some embodiments that may be combined with any of the preceding embodiments, the antibody enhances one or more TREM1 activities by inducing or maintaining cell surface clustering of TREM1. In some embodiments that may be combined with any of the preceding embodiments, the antibody is clustered by Fc-gamma receptors expressed on one or more immune cells. In some embodiments, the antibody has an Fc region as described herein, e.g., with a substitution or modification as described herein. In some embodiments that may be combined with any of the preceding embodiments, the one or more immune cells are B cells or microglial cells. In some embodiments that may be combined with any of the preceding embodiments, the enhancement of one or more TREM1 activities induced by binding of one or more TREM1 ligands to the TREM1 protein is measured in primary cells selected from the group consisting of dendritic cells, bone marrow-derived dendritic cells, monocytes, microglia, macrophages, neutrophils, NK cells, osteoclasts, dermal Langerhans cells, and Kupffer cells, or in a cell line, and the enhancement of one or more TREM1 activities induced by binding of one or more TREM1 ligands to the TREM1 protein is measured using an in vitro cell assay. In some embodiments that may be combined with any of the preceding embodiments, the antibody increases the level of soluble TREM1, increases the half-life of soluble TREM1, or both. In some embodiments that may be combined with any of the preceding embodiments, the level of soluble TREM1 is selected from the group consisting of serum levels of TREM1, cerebrospinal fluid (CSF) levels of TREM1, tissue levels of TREM1, and any combination thereof. In some embodiments that may be combined with any of the preceding embodiments, the antibody reduces the level of TREM1 in one or more cells.In some embodiments that may be combined with any of the preceding embodiments, the antibody reduces cell surface levels of TREM1, reduces intracellular levels of TREM1, reduces total levels of TREM1, or any combination thereof. In some embodiments that may be combined with any of the preceding embodiments, the antibody induces TREM1 degradation, TREM1 cleavage, TREM1 internalization, TREM1 shedding, downregulation of TREM1 expression, or any combination thereof. In some embodiments that may be combined with any of the preceding embodiments, the level of TREM1 in one or more cells is measured in primary cells selected from the group consisting of dendritic cells, bone marrow-derived dendritic cells, monocytes, microglia, macrophages, neutrophils, NK cells, osteoclasts, dermal Langerhans cells, and Kupffer cells, or in a cell line, and the cellular level of TREM1 is measured using an in vitro cell assay.

[0022] A further class of antibodies relates to antagonist antibodies that specifically bind to TREM1, inhibit TREM1, and do not activate TREM1, regardless of their configuration or their ability to form clusters. In some embodiments, anti-TREM1 antagonist antibodies bind to TREM1 and decrease, inhibit, or otherwise reduce one or more TREM1 activities. In some embodiments, antagonist anti-TREM1 antibodies of the present disclosure block or otherwise inhibit ligand binding to TREM1 expressed on the cell surface.

[0023] A further class of antibodies relates to inactive antibodies that specifically bind to TREM1 and do not modulate (eg decrease / inhibit or activate / induce) TREM1 function.

[0024] In some embodiments that may be combined with any of the preceding embodiments, the antibody inhibits one or more TREM1 activities described herein. In some embodiments that may be combined with any of the preceding embodiments, the antibody inhibits the interaction between TREM1 and one or more TREM1 ligands, inhibits TREM1 signaling, or both.

[0025] In some embodiments that may be combined with any of the preceding embodiments, the antibody cannot bind to an Fc-gamma receptor (FcγR). In some embodiments that may be combined with any of the preceding embodiments, the antibody has an IgG1, IgG2, IgG3, or IgG4 isotype. In some embodiments that may be combined with any of the preceding embodiments, (a) the antibody has a human or mouse IgG1 isotype and contains one of the following amino acids: N297A, N297Q, D270A, D265A, L234A, L235A, C226S, C229S, P238S, E233P, L234V, P238A, A327Q, A327G, P329A, K322A, L234F, L235E, P331S, T394D, A330L, M252 (b) the antibody comprises one or more amino acid substitutions in the Fc region at residue positions selected from the group consisting of Y, S254T, T256E, L328E, P238D, S267E, L328F, E233D, G237D, H268D, P271G, A330R, and any combination thereof, wherein residue numbering is according to EU or Kabat numbering, or comprises an amino acid deletion in the Fc region at a position corresponding to glycine 236; or (c) the antibody has the I type and comprises one or more amino acid substitutions in the Fc region at residue positions selected from the group consisting of P238S, V234A, G237A, H268A, H268Q, H268E, V309L, N297A, N297Q, A330S, P331S, C232S, C233S, M252Y, S254T, T256E, and any combination thereof, wherein residue numbering is according to EU or Kabat numbering; or and having the gG4 isotype and comprising one or more amino acid substitutions in the Fc region at residue positions selected from the group consisting of E233P, F234V, L234A / F234A, L235A, G237A, E318A, S228P, L236E, S241P, L248E, T394D, M252Y, S254T, T256E, N297A, N297Q, and any combination thereof, wherein residue numbering is according to EU or Kabat numbering.In some embodiments that may be combined with any of the preceding embodiments, (a) the Fc region further comprises one or more additional amino acid substitutions at a position selected from the group consisting of A330L, L234F, L235E, P331S, and any combination thereof, where the residue numbering is according to EU or Kabat numbering; (b) the Fc region further comprises one or more additional amino acid substitutions at a position selected from the group consisting of M252Y, S254T, T256E, and any combination thereof, where the residue numbering is according to EU or Kabat numbering; or (c) the Fc region further comprises a S228P amino acid substitution according to EU or Kabat numbering.

[0026] Another aspect of the present disclosure, which embodiment may be combined with any of the preceding embodiments, relates to an isolated antibody that binds to a TREM1 protein, wherein the antibody binds to i. amino acid residues 21-205 of SEQ ID NO: 1 or amino acid residues on the TREM1 protein corresponding to amino acid residues 21-205 of SEQ ID NO: 1, ii. amino acid residues 26-134 of SEQ ID NO: 1 or amino acid residues on the TREM1 protein corresponding to amino acid residues 26-134 of SEQ ID NO: 1, iii. amino acid residues 45-54 of SEQ ID NO: 1 or amino acid residues on the TREM1 protein corresponding to amino acid residues 45-54 of SEQ ID NO: 1, iv. amino acid residues 70-79 of SEQ ID NO: 1 or amino acid residues on the TREM1 protein corresponding to amino acid residues 70-79 of SEQ ID NO: 1, v. amino acid residues 89-97 of SEQ ID NO: 1. or amino acid residues on the TREM1 protein corresponding to amino acid residues 89-97 of SEQ ID NO: 1; vi. amino acid residues 119-125 of SEQ ID NO: 1 or amino acid residues on the TREM1 protein corresponding to amino acid residues 119-125 of SEQ ID NO: 1; vii. amino acid residues 83-90 of SEQ ID NO: 1 or amino acid residues on the TREM1 protein corresponding to amino acid residues 83-90 of SEQ ID NO: 1; viii. amino acid residues 191-201 of SEQ ID NO: 1 or amino acid residues on the TREM1 protein corresponding to amino acid residues 191-201 of SEQ ID NO: 1; ix. amino acid residues 116-125 of SEQ ID NO: 1 or amino acid residues on the TREM1 protein corresponding to amino acid residues 116-125 of SEQ ID NO: 1.

[0027] Another aspect of the present disclosure relates to an isolated antibody that binds to a TREM1 protein, wherein the antibody is selected from the group consisting of T1-1-T1-80, or competes with one or more antibodies selected from the group consisting of T1-1-T1-25 or T1-33-T1-80.

[0028] Another aspect of the present disclosure, which embodiments may be combined with any of the above, relates to an isolated antibody that binds to a TREM1 protein, wherein the antibody comprises a light chain variable domain and a heavy chain variable domain, and wherein the light chain variable domain, the heavy chain variable domain, or both, are selected from the group consisting of T1-1-T1-80, or comprise at least one, two, three, four, five, or six HVRs selected from HVR-L1, HVR-L2, HVR-L3, HVR-H1, HVR-H2, and HVR-H3 of a monoclonal antibody selected from the group consisting of T1-1-T1-25 or T1-33-T1-80.

[0029] In some embodiments that may be combined with any of the preceding embodiments, (a) HVR-L1 comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 9-27, (b) HVR-L2 comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 28-40, (c) HVR-L3 comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 41-119, (d) HVR-H1 comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 120-143, (e) HVR-H2 comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 144-172, or (f) HVR-H3 comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 173-247. In some embodiments that may be combined with any of the preceding embodiments, the light chain variable domain comprises: (a) an HVR-L1 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 9-27, or an amino acid sequence having at least about 90% identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 9-27; (b) an HVR-L2 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 28-40, or an amino acid sequence having at least about 90% identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 28-40; and (c) an amino acid sequence selected from the group consisting of SEQ ID NOs: 41-119, or an amino acid sequence having at least about 90% identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 41-119. and HVR-L3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 120-143, or an amino acid sequence having at least about 90% identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 120-143, (b) HVR-H2 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 144-172, or an amino acid sequence having at least about 90% identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 144-172, and (c) HVR-H3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 173-247, or an amino acid sequence having at least about 90% identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 173-247.

[0030] Another aspect of the present disclosure relates to an isolated antibody that binds to a TREM1 protein, wherein the antibody comprises a light chain variable domain comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 316-395 and / or a heavy chain variable domain comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 396-475.

[0031] Another aspect of the present disclosure relates to an isolated antibody that binds to a TREM1 protein, wherein the antibody comprises a light chain variable domain of a monoclonal antibody selected from the group consisting of T1-1-T1-80, or selected from the group consisting of T1-1-T1-25 or T1-33-T1-80, and / or a heavy chain variable domain of a monoclonal antibody selected from the group consisting of T1-1-T1-80, or selected from the group consisting of T1-1-T1-25 or T1-33-T1-80.

[0032] Another aspect of the present disclosure relates to an isolated antibody that binds to a TREM1 protein, wherein the antibody binds to essentially the same TREM1 epitope as a monoclonal antibody selected from the group consisting of T1-1-T1-80, or selected from the group consisting of T1-1-T1-25 or T1-33-T1-80.

[0033] Another aspect of the present disclosure relates to an isolated antibody that binds to a TREM1 protein, the antibody comprising a light chain variable domain and a heavy chain variable domain, wherein the light chain variable domain comprises: (a) an HVR-H1 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 120-143 or an amino acid sequence having at least about 90% identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 120-143; (b) an HVR-H2 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 144-172 or an amino acid sequence having at least about 90% identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 144-172; and (c) an HVR-H3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 173-247 or an amino acid sequence having at least about 90% identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 173-247.

[0034] In some embodiments that may be combined with any of the preceding embodiments, the TREM1 protein is a mammalian protein or a human protein. In some embodiments that may be combined with any of the preceding embodiments, the TREM1 protein is a wild-type protein. In some embodiments that may be combined with any of the preceding embodiments, the TREM1 protein is a naturally occurring mutant. In some embodiments that may be combined with any of the preceding embodiments, the TREM1 protein is a disease mutant. In some embodiments that may be combined with any of the preceding embodiments, the TREM1 protein is expressed in human dendritic cells, human macrophages, human monocytes, human osteoclasts, human dermal Langerhans cells, human Kupffer cells, human microglia, and any combination thereof.

[0035] In some embodiments that may be combined with any of the preceding embodiments, the antibody is an antibody fragment that binds one or more human proteins selected from the group consisting of human TREM1, naturally occurring variants of human TREM1, and disease variants of human TREM1, and optionally the antibody fragment is crosslinked with a second antibody fragment that binds one or more human proteins selected from the group consisting of human TREM1, naturally occurring variants of human TREM1, and disease variants of human TREM1. In some embodiments that may be combined with any of the preceding embodiments, the fragment is a Fab, Fab', Fab'-SH, F(ab')2, Fv, or scFv fragment. In some embodiments that may be combined with any of the preceding embodiments, the antibody is a murine antibody. In some embodiments that may be combined with any of the preceding embodiments, the antibody is a humanized antibody, a bispecific antibody, a multivalent antibody, a conjugated antibody, or a chimeric antibody. In some embodiments that may be combined with any of the preceding embodiments, the antibody is a monoclonal antibody. In some embodiments that may be combined with any of the preceding embodiments, the antibody is a bispecific antibody that recognizes a first antigen and a second antigen. In some embodiments that may be combined with any of the preceding embodiments, the first antigen is human TREM1 or a naturally occurring variant thereof, and the second antigen is (a) an antigen that promotes transport across the blood-brain barrier; (b) an antigen that promotes transport across the blood-brain barrier selected from the group consisting of transferrin receptor (TR), insulin receptor (HIR), insulin-like growth factor receptor (IGFR), low-density lipoprotein receptor-related proteins 1 and 2 (LPR-1 and 2), diphtheria toxin receptor, CRM197, a llama single domain antibody, TMEM30(A), a protein transduction domain, TAT, Syn-B, penetratin, a polyarginine peptide, an angiopeptide, and ANG1005; (c) a disease-causing agent selected from the group consisting of a disease-causing peptide or protein or a disease-causing nucleic acid, wherein the disease-causing nucleic acid is an antisense GGCCCC(G2C4) repeat-expanded RNA and the disease-causing protein is amyloid beta, oligomeric amyloid beta, amyloid beta plaque,Amyloid precursor protein or its fragment, tau, IAPP, α-synuclein, TDP-43, FUS protein, C9orf72 (chromosome 9 open reading frame 72), c9RAN protein, prion protein, PrPSc, huntingtin, calcitonin, superoxide dismutase, ataxin, ataxin 1, ataxin 2, ataxin 3, ataxin 7, ataxin 8, ataxin 10, Lewy bodies, atrial natriuretic factor, islet amyloid polypeptide, insulin, apolipoprotein AI, serum amyloid A, medin, prolactin, transthyretin, lysozyme, β2-microglobulin, gelsolin, keratoepithelin, cystatin, immunoglobulin light chain AL, S-IBM protein, repeat-associated non-ATG (RAN) translation products, dipeptide repeat (DPR) peptide (d) a disease-causing agent selected from the group consisting of CD40, OX40, ICOS, CD28, CD137 / 4-1BB, CD27, GITR, PD-L1, CTLA-4, PD-L2, PD-1, B7-H3, B7-H4, HVEM, BTLA, KIR, GAL9, TIM3, A2AR, LAG, and phosphatidylserine; and (e) a protein, lipid, polysaccharide, or glycolipid expressed on one or more tumor cells. In some embodiments that may be combined with any of the preceding embodiments, the antibody is directed against a disease-causing peptide, a disease-causing protein, amyloid beta, oligomeric amyloid beta, amyloid beta plaques, amyloid precursor protein or fragments thereof, tau, IAPP, alpha synuclein, TDP-43, FUS protein, C9orf72 (chromosome 9 open reading frame 72), prion protein, PrPSc, huntingtin, calcitonin, superoxide dismutase, ataxin, ataxin 1, ataxin 2, ataxin 3, ataxin 7, ataxin 8,Ataxin 10, Lewy bodies, atrial natriuretic factor, islet amyloid polypeptide, insulin, apolipoprotein AI, serum amyloid A, medin, prolactin, transthyretin, lysozyme, β2 microglobulin, gelsolin, keratoepithelin, cystatin, immunoglobulin light chain AL, S-IBM protein, repeat-associated non-ATG (RAN) translation products, dipeptide repeat (DPR) peptides, glycine-alanine (GA) repeat peptides, glycine-proline (GP) repeat peptides, glycine-arginine (GR) repeat peptides, proline-alanine (PA) repeat peptides, ubiquitin, and proline-arginine (PR) repeat peptides, and any combination thereof. or in combination with one or more antibodies that bind an immunomodulatory protein selected from the group consisting of CD40, OX40, ICOS, CD28, CD137 / 4-1BB, CD27, GITR, PD-L1, CTLA-4, PD-L2, PD-1, B7-H3, B7-H4, HVEM, BTLA, KIR, GAL9, TIM3, A2AR, LAG-3, TREM1, TREM1, CD33, Siglec-5, Siglec-9, Siglec-11, phosphatidylserine, a disease-causing nucleic acid, antisense GGCCCC (G2C4) repeat-expanded RNA, and any combination thereof. In some embodiments that may be combined with any of the preceding embodiments, when administered to an individual, the compound increases memory, reduces cognitive deficits, or both. In some embodiments that may be combined with any of the preceding embodiments, the antibody specifically binds to both human TREM1 and mouse TREM1. In some embodiments that may be combined with any of the preceding embodiments, the antibody has a dissociation constant (K,) for human TREM1 and mouse TREM1 in the range of about 12.8 nM to about 1.2 nM or less. D In some embodiments that may be combined with any of the preceding embodiments, the antibody has a dissociation constant (K) for human TREM1 in the range of about 12.8 nM to about 2.9 nM or less. DIn some embodiments that may be combined with any of the preceding embodiments, the antibody has a dissociation constant (K) for mouse TREM1 in the range of about 10.4 nM to about 1.2 nM or less. D )

[0036] Other aspects of the disclosure relate to an isolated nucleic acid comprising a nucleic acid sequence encoding an antibody according to any one of the preceding claims. Other aspects of the disclosure relate to a vector comprising the nucleic acid of any of the preceding embodiments. Other aspects of the disclosure relate to an isolated host cell comprising the vector of any of the preceding embodiments. Other aspects of the disclosure relate to a method for producing an antibody that binds TREM1, the method comprising culturing the host cell of any of the preceding embodiments so that the antibody is produced. In some embodiments, the method further comprises recovering the antibody produced by the cell. Other aspects of the disclosure relate to an isolated antibody that binds TREM1 produced by the method of any of the preceding embodiments. Other aspects of the disclosure relate to a pharmaceutical composition comprising the antibody of any of the preceding embodiments and a pharmaceutically acceptable carrier.

[0037] Other aspects of the present disclosure include the treatment of dementia, frontotemporal dementia, Alzheimer's disease, vascular dementia, mixed dementia, Creutzfeldt-Jakob disease, normal pressure hydrocephalus, amyotrophic lateral sclerosis, Huntington's chorea, tauopathy, Nasu-Hakola disease, stroke, acute trauma, chronic trauma, cognitive deficits, memory loss, lupus, acute and chronic colitis, rheumatoid arthritis, wound healing, Crohn's disease, inflammatory bowel disease, ulcerative colitis, obesity, Malaria, essential tremor, central nervous system lupus, Behçet's disease, Parkinson's disease, dementia with Lewy bodies, multiple system atrophy, Shy-Drager syndrome, progressive supranuclear palsy, corticobasal ganglionic degeneration, acute disseminated encephalomyelitis, granulomatous disorders, sarcoidosis, diseases of aging, stroke, spinal cord injury, traumatic brain injury, age-related macular degeneration, glaucoma, retinitis pigmentosa, retinal degeneration, respiratory tract infections, sepsis, eye infections Diseases, systemic infections, lupus, arthritis, multiple sclerosis, low bone density, osteoporosis, bone formation, osteopetrosis, atherosclerosis, Paget's bone disease, bladder cancer, brain cancer, gliomas such as low-grade gliomas and glioblastomas, cervical cancer, breast cancer, colon cancer, rectal cancer, endometrial cancer, kidney cancer, renal cell carcinoma, renal pelvis cancer, leukemia, lung cancer, such as non-small cell lung cancer, melanoma, non-Hodgkin's lymphoma, pancreatic cancer, prostate cancer, ovarian cancer, fibroids, fibroids, fibroids, fibroids, fibroids, fibroids, fibroids, fibromyalgia ... Fibrosarcoma, acute lymphocytic leukemia (ALL), acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL), chronic myelogenous leukemia (CML), multiple myeloma, polycythemia vera, essential thrombocytosis, primary or idiopathic myelofibrosis, primary or idiopathic myelosclerosis, bone marrow derived tumors, thyroid cancer, infectious diseases, CNS herpes, parasitic infections, trypanosomiasis infections, cruzi infections, Pseudomonas aeruginosa infections, Leishmania donovani infections, group B Streptococcus infections, Campylobacter jejuni infections, Neisseria meningiditis infections, HIV type 1 and Haemophilus influenzae infectionsIn some embodiments, the isolated antibody is an antibody of any of the preceding embodiments.

[0038] Other aspects of the present disclosure include the treatment of dementia, frontotemporal dementia, Alzheimer's disease, vascular dementia, mixed dementia, Creutzfeldt-Jakob disease, normal pressure hydrocephalus, amyotrophic lateral sclerosis, Huntington's chorea, tauopathy, Nasu-Hakola disease, stroke, acute trauma, chronic trauma, cognitive deficits, memory loss, lupus, acute and chronic colitis, rheumatoid arthritis, atherosclerosis, wound healing, Crohn's disease, inflammatory bowel disease, ulcerative colitis, obesity, malaria, essential tremor, central nervous system lupus, Behcet's disease , Parkinson's disease, dementia with Lewy bodies, multiple system atrophy, Shy-Drager syndrome, progressive supranuclear palsy, corticobasal ganglionic degeneration, acute disseminated encephalomyelitis, granulomatous disorders, sarcoidosis, diseases of aging, stroke, spinal cord injury, traumatic brain injury, age-related macular degeneration, glaucoma, retinitis pigmentosa, retinal degeneration, respiratory tract infections, sepsis, eye infections, systemic infections, lupus, arthritis, multiple sclerosis, low bone density, osteoporosis, bone formation, osteopetrosis, Paget's bone disease, bladder cancer, brain cancer, e.g., low-grade myeloma Gliomas such as gliomas or glioblastomas, breast cancer, cervical cancer, colon cancer, rectal cancer, endometrial cancer, kidney cancer, renal cell carcinoma, renal pelvic cancer, leukemia, lung cancer, e.g., non-small cell lung cancer, melanoma, non-Hodgkin's lymphoma, pancreatic cancer, prostate cancer, ovarian cancer, fibrosarcoma, acute lymphocytic leukemia (ALL), acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL), chronic myelogenous leukemia (CML), multiple myeloma, polycythemia vera, essential thrombocytosis, primary or idiopathic myelofibrosis, primary or idiopathic myelosclerosis, bone marrow-derived The present invention relates to an isolated antibody that binds a TREM1 protein as described herein for use in preventing, reducing the risk of, or treating an individual having a disease, disorder, or injury selected from the group consisting of a tumor, thyroid cancer, an infectious disease, CNS herpes, a parasitic infection, a Trypanosoma infection, a Cruzi infection, a Pseudomonas aeruginosa infection, a Leishmania donovani infection, a Group B Streptococcus infection, a Campylobacter jejuni infection, a meningococcal infection, HIV type I, and a Haemophilus influenzae infection. In some embodiments, the isolated antibody is an antibody of any of the preceding embodiments.

[0039] Other aspects of the present disclosure include the treatment of dementia, frontotemporal dementia, Alzheimer's disease, vascular dementia, mixed dementia, Creutzfeldt-Jakob disease, normal pressure hydrocephalus, amyotrophic lateral sclerosis, Huntington's chorea, tauopathy, Nasu-Hakola disease, stroke, acute trauma, chronic trauma, cognitive deficits, memory loss, lupus, acute and chronic colitis, rheumatoid arthritis, wound healing, Crohn's disease, inflammatory bowel disease, ulcerative colitis, obesity, malaria, essential tremor, central nervous system lupus, Behcet's disease, Parkinson's disease, and the like. Lewy body dementia, multiple system atrophy, Shy-Drager syndrome, progressive supranuclear palsy, corticobasal ganglionic degeneration, acute disseminated encephalomyelitis, granulomatous disorders, sarcoidosis, diseases of aging, stroke, spinal cord injury, traumatic brain injury, age-related macular degeneration, glaucoma, retinitis pigmentosa, retinal degeneration, respiratory tract infections, sepsis, eye infections, systemic infections, lupus, arthritis, multiple sclerosis, low bone density, osteoporosis, bone formation, osteopetrosis, Paget's bone disease, bladder cancer, brain cancer, e.g., low-grade neurological Gliomas such as gliomas or glioblastomas, breast cancer, cervical cancer, colon cancer, rectal cancer, endometrial cancer, kidney cancer, renal cell carcinoma, renal pelvis cancer, leukemia, lung cancer, for example non-small cell lung cancer, melanoma, non-Hodgkin's lymphoma, pancreatic cancer, prostate cancer, ovarian cancer, fibrosarcoma, acute lymphocytic leukemia (ALL), acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL), chronic myeloid leukemia (CML), multiple myeloma, polycythemia vera, essential thrombocytosis, primary or idiopathic myelofibrosis, primary or idiopathic myelosclerosis, The present invention relates to the use of an isolated antibody that binds to a TREM1 protein in the manufacture of a medicament for preventing, reducing the risk of, or treating an individual having a disease, disorder, or injury selected from the group consisting of myeloid-derived tumors, thyroid cancer, infectious diseases, CNS herpes, parasitic infections, Trypanosoma infection, Cruzi infection, Pseudomonas aeruginosa infection, Leishmania donovani infection, Group B Streptococcus infection, Campylobacter jejuni infection, Neisseria meningitidis infection, HIV type 1, and Haemophilus influenzae. In some embodiments, the isolated antibody is an antibody of any of the preceding embodiments.

[0040] In some embodiments that may be combined with any of the preceding embodiments, the method further comprises administering to the individual at least one antibody that specifically binds an inhibitory checkpoint molecule and / or another standard or investigational anti-cancer therapy. In some embodiments that may be combined with any of the preceding embodiments, the at least one antibody that specifically binds an inhibitory checkpoint molecule is administered in combination with an isolated antibody. In some embodiments that may be combined with any of the preceding embodiments, the at least one antibody that specifically binds an inhibitory checkpoint molecule is selected from the group consisting of an anti-PD-L1 antibody, an anti-CTLA4 antibody, an anti-PD-L2 antibody, an anti-PD-1 antibody, an anti-B7-H3 antibody, an anti-B7-H4 antibody, and an anti-HVEM antibody, an anti-B- and T-lymphocyte attenuator (BTLA) antibody, an anti-killer inhibitory receptor (KIR) antibody, an anti-GAL9 antibody, an anti-TIM3 antibody, an anti-A2AR antibody, an anti-LAG-3 antibody, an anti-phosphatidylserine antibody, an anti-CD27 antibody, and any combination thereof. In some embodiments that may be combined with any of the preceding embodiments, the standard and investigational anti-cancer therapy is one or more therapies selected from the group consisting of radiation therapy, cytotoxic chemotherapy, targeted therapy, hormone therapy, imatinib (Gleevec®), trastuzumab (Herceptin®), bevacizumab (Avastin®), ofatumumab (Arzerra®), rituximab (Rituxan®, MabThera®, Zytux®), cryotherapy, ablation, radiofrequency ablation, adoptive cell transfer (ACT), chimeric antigen receptor T cell transfer (CAR-T), vaccine therapy, and cytokine therapy. In some embodiments that may be combined with any of the preceding embodiments, the method further comprises administering to the individual at least one antibody that specifically binds an inhibitory cytokine. In some embodiments that may be combined with any of the preceding embodiments, at least one antibody that specifically binds to an inhibitory cytokine is administered in combination with an isolated antibody.In some embodiments that may be combined with any of the preceding embodiments, the at least one antibody that specifically binds an inhibitory cytokine is selected from the group consisting of an anti-CCL2 antibody, an anti-CSF-1 antibody, an anti-IL-2 antibody, and any combination thereof. In some embodiments that may be combined with any of the preceding embodiments, the method further comprises administering to the individual at least one agonist antibody that specifically binds a stimulatory checkpoint protein. In some embodiments that may be combined with any of the preceding embodiments, the at least one agonist antibody that specifically binds a stimulatory checkpoint protein is administered in combination with an isolated antibody. In some embodiments that may be combined with any of the preceding embodiments, the at least one agonist antibody that specifically binds to a stimulatory checkpoint protein is selected from the group consisting of an agonist anti-CD40 antibody, an agonist anti-OX40 antibody, an agonist anti-ICOS antibody, an agonist anti-CD28 antibody, an agonist anti-CD137 / 4-1BB antibody, an agonist anti-CD27 antibody, an agonist anti-glucocorticoid-induced TNFR-related protein GITR antibody, and any combination thereof. In some embodiments that may be combined with any of the preceding embodiments, the method further comprises administering to the individual at least one stimulatory cytokine. In some embodiments that may be combined with any of the preceding embodiments, the at least one stimulatory cytokine is administered in combination with an isolated antibody. In some embodiments that may be combined with any of the preceding embodiments, the at least one stimulatory cytokine is selected from the group consisting of TNF-α, IL-10, IL-6, IL-8, CRP, a TGF-β member of the chemokine protein family, an IL20 family member, IL-33, LIF, OSM, CNTF, TGF-β, IL-11, IL-12, IL-17, IL-8, IL-23, IFN-α, IFN-β, IL-2, IL-18, GM-CSF, G-CSF, and any combination thereof.

[0041] Other aspects of the present disclosure relate to methods for enhancing one or more TREM1 activities induced by binding of one or more TREM1 ligands to a TREM1 protein in an individual in need thereof, the method comprising administering to the individual a therapeutically effective amount of an isolated antibody that binds to a TREM1 protein. Other aspects of the present disclosure relate to an isolated antibody that binds to a TREM1 protein for use in enhancing one or more TREM1 activities induced by binding of one or more TREM1 ligands to a TREM1 protein in an individual in need thereof. Other aspects of the present disclosure relate to the use of an isolated antibody that binds to a TREM1 protein in the manufacture of a medicament for enhancing one or more TREM1 activities induced by binding of one or more TREM1 ligands to a TREM1 protein in an individual in need thereof. In some embodiments, the isolated antibody is the antibody of any of the preceding embodiments.

[0042] Other aspects of the disclosure relate to methods of inducing one or more TREM1 activities in an individual in need thereof, the method comprising administering to the individual a therapeutically effective amount of an isolated antibody that binds to a TREM1 protein. Other aspects of the disclosure relate to an isolated antibody that binds to a TREM1 protein for use in inducing one or more TREM1 activities in an individual in need thereof. Other aspects of the disclosure relate to the use of an isolated antibody that binds to a TREM1 protein in the manufacture of a medicament for inducing one or more TREM1 activities in an individual in need thereof. In some embodiments, the isolated antibody is the antibody of any of the preceding embodiments.

[0043] Other aspects of the present disclosure relate to methods for inducing one or more TREM1 activities and enhancing one or more TREM1 activities induced by binding of one or more TREM1 ligands to a TREM1 protein in an individual in need thereof, the method comprising administering to the individual a therapeutically effective amount of an isolated antibody that binds to a TREM1 protein. Other aspects of the present disclosure relate to an isolated antibody that binds to a TREM1 protein for use in inducing one or more TREM1 activities and enhancing one or more TREM1 activities induced by binding of one or more TREM1 ligands to a TREM1 protein in an individual in need thereof. Other aspects of the present disclosure relate to the use of an isolated antibody that binds to a TREM1 protein in the manufacture of a medicament for inducing one or more TREM1 activities and enhancing one or more TREM1 activities induced by binding of one or more TREM1 ligands to a TREM1 protein in an individual in need thereof. In some embodiments, the isolated antibody is the antibody of any of the preceding embodiments.

[0044] Other aspects of the disclosure relate to methods of reducing the level of TREM1 in one or more cells in an individual in need thereof, comprising administering to the individual a therapeutically effective amount of an isolated antibody that binds to the TREM1 protein. Other aspects of the disclosure relate to an isolated antibody that binds to the TREM1 protein for use in reducing the level of TREM1 in one or more cells in an individual in need thereof. Other aspects of the disclosure relate to the use of an isolated antibody that binds to the TREM1 protein in the manufacture of a medicament for reducing the level of TREM1 in one or more cells in an individual in need thereof. In some embodiments, the isolated antibody is the antibody of any of the preceding embodiments.

[0045] Other aspects of the present disclosure relate to methods of inducing or promoting innate immune cell survival or wound healing in an individual in need thereof, the method comprising administering to the individual a therapeutically effective amount of an isolated agonist antibody that binds to a TREM1 protein. Other aspects of the present disclosure relate to an isolated agonist antibody that binds to a TREM1 protein for use in inducing or promoting innate immune cell survival or wound healing in an individual in need thereof. Other aspects of the present disclosure relate to the use of an isolated agonist antibody that binds to a TREM1 protein in the manufacture of a medicament for inducing or promoting innate immune cell survival or wound healing in an individual in need thereof. In some embodiments, the isolated agonist antibody is the agonist antibody of any of the preceding embodiments.

[0046] Other aspects of the disclosure relate to methods of increasing memory, reducing cognitive deficits, or both, in an individual in need thereof, comprising administering to the individual a therapeutically effective amount of an isolated agonist antibody that binds to a TREM1 protein. Other aspects of the disclosure relate to isolated agonist antibodies that bind to a TREM1 protein for use in increasing memory, reducing cognitive deficits, or both, in an individual in need thereof. Other aspects of the disclosure relate to the use of isolated agonist antibodies that bind to a TREM1 protein in the manufacture of a medicament for increasing memory, reducing cognitive deficits, or both, in an individual in need thereof. In some embodiments, the isolated agonist antibody is the agonist antibody of any of the preceding embodiments. [Brief explanation of the drawings]

[0047] [Figure 1A] FIG. 1 shows an amino acid sequence alignment of the human TREM1 protein (SEQ ID NO: 498) and the human NCTR2 protein (SEQ ID NO: 499), depicting the homology between the two proteins. [Figure 1B]FIG. 1 shows an amino acid sequence alignment of the human TREM1 protein (SEQ ID NO: 500) and the mouse TREM1 protein (SEQ ID NO: 501), depicting the homology between the two proteins. [Figure 2] FIG. 1 shows an amino acid sequence alignment of human TREM1 protein (SEQ ID NO: 502) and human TREM2 protein (SEQ ID NO: 503), depicting the homology between the two proteins. [Figure 3A] FIG. 1 shows FACS histograms of TREM1 antibodies T1-1 to T1-80 binding to a rodent Chinese hamster ovary cell line (CHO) expressing recombinant human TREM1. [Figure 3B] Figure 1 shows FACS histograms of TREM1 antibodies T1-1 to T1-80 binding to CHO cells expressing mouse TREM1. Shaded histograms represent parental TREM1-negative CHO cells. Black histograms represent TREM1-positive cell populations. Antibodies mIgG1, mIgG2A, and ISO88 represent negative isotype controls. Antibodies MAB0170, RDhT1, and RDmT1 represent positive controls. [Figure 4A] Figure 1 shows FACS histograms of TREM1 antibodies T1-1 to T1-80 binding to primary human neutrophils. Antibody ISO88 represents a negative isotype control, and MAB0170 represents a positive control. Shaded histograms represent cells stained with anti-human Fc secondary antibody only. Histograms outlined with a black line represent the TREM1-positive cell population. [Figure 4B] Figure 1 shows FACS histograms of TREM1 antibodies T1-1 to T1-80 binding to primary human monocytes. Shaded histograms show binding of the isotype antibody negative control. Histograms outlined with black lines represent binding of TREM1 antibodies. [Figure 5A-B]Figure 1A shows a structural map of human TREM1 (PDB1Q8M) highlighting the epitopes defined for the indicated anti-TREM1 antibodies. The amino acid region D38-F48 is shown in black as the predicted epitope for MAB0170, a positive control antibody for human TREM1. Figure 1B shows a structural map of human TREM1 (PDB1Q8M) highlighting the epitopes defined for the indicated anti-TREM1 antibodies. The amino acid regions L45-A54, T70-P79, D89-R97, and P119-L125 are shown in black as the predicted epitopes for T1-53 and T1-63. [Figure 5C-D] (C) Structural map of human TREM1 (PDB1Q8M) highlighting the epitopes defined for the indicated anti-TREM1 antibodies. The amino acid regions L45-A54 and Y116-L125 are shown in black as predicted epitopes for T1-10 and T1-61. (D) Structural map of human TREM1 (PDB1Q8M) highlighting the epitopes defined for the indicated anti-TREM1 antibodies. The amino acid region G83-Y90 is shown in black as predicted epitopes for T1-34, -39, -62, -71, and -76. [Figure 6A-B]A shows a FACS histogram of recombinant His-tagged human PGLYRP1 binding to CHO cells expressing human TREM1 (CHO-huTREM1). PGLYRP1 was detected using a PE-conjugated anti-HIS tag secondary antibody. As a negative control (shaded histogram), mouse PGLYRP1 was added to CHO-huTREM1 cells. B shows a contour plot of human PGLYRP1 complexed with peptidoglycan isolated from Bacillus subtilis (PGN-BS) or Staphylococcus aureus (PGN-SA) binding to CHO-huTREM1. Gates indicate the percentage of the huPGLYRP1-high CHO-huTREM1 population that exhibits increased binding activity for receptor binding in the context of the ligand complex with PGN-BS. Ligand complexes with PGN-SA do not increase the percentage of the huPGLYRP1-high CHO-huTREM1 population. [Figure 6C] Contour plots of mouse PGLYRP1 complexed with peptidoglycan isolated from Bacillus subtilis (PGN-BS) or Staphylococcus aureus (PGN-SA) bound to CHO-huTREM1. Gates indicate percentages of the mPGLYRP1-high CHO-huTREM1 population. [Figure 6D] This figure shows the sequestration of soluble TREM1-ligand complexes binding to CHO-huTREM1 cells by anti-TREM1 antibodies T1-40 to T1-80. The TREM1 ligand consisted of 50 nM recombinant His-tagged human PGLYRP1 complexed with 10 μg / mL PGN-BS. TREM1 ligand binding to CHO-huTREM1 cells was detected using an anti-HIS-tagged PE secondary antibody. Antibodies huIgG1 and huIgG4 represent isotype negative controls, and Mab0170 represents a positive control. Results are representative of the full set of available TREM1 antibodies and are depicted as percent ligand binding, calculated by dividing the MFI values ​​of samples treated with the anti-TREM1 antibody by the MFI values ​​of samples treated with the isotype control. [Figure 7] Figure 1 shows human TREM1-dependent GFP reporter induction in a cell-based assay. Cells were treated with decreasing concentrations of either plate-bound full-length human IgG1 isotype control or anti-TREM1 antibodies T1-77, -76, -69, -72, -71, -61, -59, -40, -39, -34, and -22. Results are expressed as fold over background. Background levels are set to 1 on the y-axis. Antibody huIgG1 is the isotype-negative control. [Figure 8A-B] Figure 8A shows human TREM1-dependent GFP reporter induction in a cell-based assay. Cells were treated with either a soluble full-length isotype control or soluble full-length anti-TREM1 antibodies T1-77, -78, -79, -80, -12, -40, -51, -52, -62, -63, -16, -22, and -39. Antibody huIgG1 served as an isotype-negative control. Figure 8B shows human TREM1-dependent GFP reporter induction in a cell-based assay. Cells were treated with either a soluble full-length isotype control or soluble full-length anti-TREM1 antibodies T1-64 to T1-76. Results are representative of the full set of available TREM1 antibodies and are depicted as absolute MFI values. [Figure 8C] FIG. 1 shows dose-response curves of GFP expression induced by increasing concentrations of soluble full-length antibodies T1-62 and T1-76, or isotype control, in a cell-based assay. [Figure 9A]Figure 1 shows human TREM1-dependent GFP reporter induction in a cell-based assay. Cells were treated with either a soluble full-length isotype control or soluble full-length anti-TREM1 antibodies T1-77, -78, -79, -80, -12, -40, -51, -52, -62, -63, -16, -22, and -39 in the presence of a soluble TREM1 ligand complex. The TREM1 ligand consisted of 50 nM human PGLYRP1 (Invivogen) complexed with 10 μg / mL PGN-BS. Antibody huIgG1 served as an isotype negative control. Antibody Mab0170 represented a positive control. Results are representative of the full set of available TREM1 antibodies and are depicted as absolute MFI values. [Figure 9B] This figure shows the ability of agonistic TREM1 antibodies to enhance TREM1 ligand-induced GFP expression in a reporter cell-based assay. Cells were treated with decreasing concentrations of anti-TREM1 antibodies T1-62 or T1-63 in the presence or absence of a soluble TREM1 ligand complex consisting of recombinant human PGLYRP1 and PGN-BS. The "no ligand" sample represents basal GFP expression in cells not stimulated with antibody or ligand. Results are depicted as absolute MFI values. [Figure 9C] This figure shows the ability of agonist and antagonist TREM1 antibodies to either enhance or inhibit GFP expression induced by TREM1 ligand in a reporter cell-based assay. TREM1 ligand was supplied by stimulating primary human neutrophils with 10 μg / mL PGN-BS or PGN-SA, followed by co-culturing BWZ reporter cells in the presence or absence of anti-TREM1 antibodies T1-10, -63, -62, -61, -34, and -40. The "No Ab" sample represents reporter cells not treated with antibody, whereas the "huIgG" sample represents reporter cells treated with a human IgG1 isotype negative control. [Figure 9D](Figure 1 shows the ability of antagonist TREM1 antibodies to inhibit TREM1 ligand-induced GFP expression in a reporter cell-based assay. Primary human neutrophils were stimulated with 10 μg / mL PGN-SA to provide a natural source of TREM1 ligand, which was then co-cultured with BWZ reporter cells along with increasing concentrations of the anti-TREM1 antibodies T1-34, -22, -40, and -39. Results are depicted as absolute MFI values. [Figure 10A] Figure 1 shows TREM1-mediated respiratory burst from primary human monocytes. Cells were stimulated with plate-bound full-length human IgG1 isotype control or anti-TREM1 antibodies T1-8, -10, -12, -18, -19, 21, -33, -34, 40, -43, -62, -63, -71, -75, -76, -77, -78, -79, and -80. Antibody huIgG1 is an isotype-negative control. [Figure 10B] Figure 1 shows TREM1-mediated respiratory burst from primary human monocytes. Cells were left untreated or stimulated with plate-bound Fab fragments of human IgG1 isotype control or Fab fragments of anti-TREM1 antibodies T1-8, -10, -12, -16, -20, 22, -33, -34, -39, -40, -41, -43, -51, -52, -53, -55, -57, -62, -63, -69, -71, -75, -76, and -77. [Figure 10C] This figure shows TREM1-mediated respiratory burst from primary human neutrophils. Cells were stimulated with a soluble full-length human IgG1 isotype control or anti-TREM1 antibodies T1-63, -62, -71, -76, -77, -39, -40, -34, -10, -57, -22, -51, -52, -45, -46, -56, -59, -61, -69, -72, -78, and -79. Antibody huIgG1 serves as an isotype-negative control. In all experiments, reactive oxygen species (ROS) production was monitored by labeling cells with 2 μM of the fluorescent indicator CM-H2DCFDA. [Figure 10D]Figure 1 shows TREM1-mediated release of cell-free extracellular DNA from primary human neutrophils. Cells were stimulated with soluble full-length human IgG1 isotype control or anti-TREM1 antibodies T1-63, -62, -71, -76, -77, -39, -40, -34, -57, -52, -56, and -69. Extracellular DNA was detected by staining the supernatant with 5 μM of the fluorescent indicator Sytox Green. [Figure 11A] Figure 1 shows downregulation of the TREM1 receptor in primary human monocytes in response to antibody stimulation. Cells were treated with either a soluble full-length isotype control or a soluble full-length anti-TREM1 antibody from the Bin1 category, and then stained with a commercially available bin2 anti-TREM1 APC antibody (TREM-26, Biolegend). [Figure 11B] (Figure 1 shows downregulation of the TREM1 receptor in primary neutrophils in response to antibody stimulation. Cells were treated with either a soluble full-length isotype control or the soluble full-length Bin1 anti-TREM1 antibodies T1-2, -12, -33, -34, -56, -57, -71, -75, -76, -77, and -80. Antibody huIgG1 represents an isotype negative control, and Mab0170 represents a positive control. [Figure 11C] (a) Downregulation of TREM1 receptor in primary monocytes treated with Bin2 antibody and subsequently stained with Mab0170, a fluorophore-conjugated Bin1 antibody. Antibodies huIgG1 and huIgG4 represent isotype negative controls. Results are expressed as median absolute fluorescence intensity (MFI) values. [Figure 12A-B]Figure 12A shows the relative viability of primary human monocytes cultured for 20 hours in the absence or presence of TREM1 and Toll-like receptor ligands. Figure 12B shows the relative viability of primary human neutrophils cultured for 20 hours in the absence or presence of TREM1 and Toll-like receptor ligands. Cells were treated with either 500 nM human PGLYRP1, 10 μg / mL PGN-BS, a soluble TREM1 ligand complex (500 nM PGLYRP1 + 10 μg / mL PGN-BS), or 1 μg / mL LPS. Cell viability was determined by ATP quantification using a luciferase-based assay kit (CellTiter-Glo; Promega) according to the manufacturer's instructions. [Figure 12C] This figure shows the ability of anti-TREM1 antibodies to enhance the relative viability of primary human neutrophils cultured for 20 hours with a soluble TREM1-ligand complex. Cells were treated with either a human isotype control (huIgG1) or TREM1 antibodies T1-34, -63, -71, and -76, or left untreated, in the presence of 10 μg / mL PGN-BS or a soluble TREM1-ligand complex (500 nM PGLYRP1 + 10 μg / mL PGN-BS). Cell viability was determined by ATP quantification using a luciferase-based assay kit (CellTiter-Glo; Promega) according to the manufacturer's instructions. [Figure 13] FIG. 1 shows TREM1 expression in the indicated immune cell populations present in the spleen (SPL) or tumor (Tum) of naive or EMT-6 tumor-bearing mice. [Figure 14]1A-C show alignments of the heavy chain sequences of exemplary antagonistic enhancing and mimetic anti-TREM1 antibodies of the present disclosure. (VH3-21*01 = SEQ ID NO: 504); (ADI-19082 = SEQ ID NO: 505); (ADI-19113 = SEQ ID NO: 506); (ADI-19108 = SEQ ID NO: 507); (ADI-19101 = SEQ ID NO: 508); (ADI-19080 = SEQ ID NO: 509); (ADI-19114 = SEQ ID NO: 510); (VH4-0B*01 = SEQ ID NO: 511); (ADI-19139 = SEQ ID NO: 512); (ADI-19135 = SEQ ID NO: 513); (ADI-19136 = SEQ ID NO: 514); (ADI-19137 = SEQ ID NO: 515); (ADI-19154 = SEQ ID NO: 516); (VH4-31*01 = SEQ ID NO: 517); (ADI-19098 = SEQ ID NO: 518; (ADI-19138 = SEQ ID NO: 519); (VH3-09*01 = SEQ ID NO: 520); (ADI-19092 = SEQ ID NO: 521); (ADI-19085 = SEQ ID NO: 522); (ADI-19090 = SEQ ID NO: 523); (ADI-19150 = SEQ ID NO: 524); (ADI-19147 = SEQ ID NO: 525); (ADI-19152 = SEQ ID NO: 526); (ADI-19132 = SEQ ID NO: 527); (ADI-19083 = SEQ ID NO: 528); (ADI-19148 = SEQ ID NO: 529); (ADI-19131 = SEQ ID NO: 530); (ADI-19151 = SEQ ID NO: 531); and (ADI-19149 = SEQ ID NO: 532). [Figure 15]15A-15J show alignments of the heavy chain variable region sequences of various anti-TREM1 antibodies of the present disclosure. Figures 15A-15E show the CDR2 sequences from the heavy chain sequences, and Figures 15F-15J show the FR4 sequences from the remainder of the heavy chain sequences. (VH5-51*01 = SEQ ID NO: 533); (ADI-19144 = SEQ ID NO: 463); (VH1-69*01 = SEQ ID NO: 534); (ADI-19070 = SEQ ID NO: 399); (ADI-19068 = SEQ ID NO: 397); (ADI-19129 = SEQ ID NO: 449); (ADI-19069 = SEQ ID NO: 398); (ADI-19120 = SEQ ID NO: 442); (ADI-19126 = SEQ ID NO: 446); (ADI-19067 = SEQ ID NO: 396); (ADI-19127 = SEQ ID NO: 447); (VH1- 18*01 = SEQ ID NO: 535; (ADI-19145 = SEQ ID NO: 464); (ADI-19143 = SEQ ID NO: 462); (ADI-19146 = SEQ ID NO: 465); (VH1-02*02 = SEQ ID NO: 536); (ADI-19142 = SEQ ID NO: 461); (VH1-46*01 = SEQ ID NO: 537); (ADI-19097 = SEQ ID NO: 421); (ADI-19072 = SEQ ID NO: 401); (ADI-19121 = SEQ ID NO: 443); (ADI-19125 = SEQ ID NO: 445); (ADI-19122 = SEQ ID NO: 444; (ADI-19128 = SEQ ID NO: 448); (ADI-19076 = SEQ ID NO: 404); (ADI-19117 = SEQ ID NO: 438); (ADI-19073 = SEQ ID NO: 402); (ADI-19130 = SEQ ID NO: 450); (ADI-19071 = SEQ ID NO: 400); (ADI-19119 = SEQ ID NO: 439); (ADI-19123 = SEQ ID NO: 440); (ADI-19124 = SEQ ID NO: 441); (ADI-19074 = SEQ ID NO: 403); (ADI-19077 = SEQ ID NO: 405); (VH4-0B*01 = SEQ ID NO: 538); (ADI-19139 = SEQ ID NO: 458); (ADI-19135 = SEQ ID NO: 454); (ADI-19136 = SEQ ID NO: 455); (ADI-19137 = SEQ ID NO: 456); (ADI-19154 = SEQ ID NO: 472); (VH4-59*01 = SEQ ID NO: 539); (ADI-19084 = SEQ ID NO: 412); (ADI-19089 = SEQ ID NO: 417); (VH4-31*01 = SEQ ID NO: 540); (ADI-19098 = SEQ ID NO: 422);(ADI-19138 = SEQ ID NO: 457); (VH4-39*01 = SEQ ID NO: 541); (ADI-19102 = SEQ ID NO: 424); (ADI-19104 = SEQ ID NO: 426); (ADI-19140 = SEQ ID NO: 459); (ADI-19105 = SEQ ID NO: 427); (ADI-19103 = SEQ ID NO: 425); (ADI-19156 = SEQ ID NO: 474); (ADI-19079 = SEQ ID NO: 407); (ADI-19141 = SEQ ID NO: 460); (ADI-19155 = SEQ ID NO: 473); (ADI-19078 = SEQ ID NO: 406); (ADI-19133 = SEQ ID NO: 453; (VH3-72*01 = SEQ ID NO: 542); (ADI-19086 = SEQ ID NO: 414); (VH3-07*01 = SEQ ID NO: 543); (ADI-19087 = SEQ ID NO: 415); (VH3-33*01 = SEQ ID NO: 544); (ADI-19107 = SEQ ID NO: 428); (ADI-19116 = SEQ ID NO: 437); (ADI-19159 = SEQ ID NO: 475); (ADI-19111 = SEQ ID NO: 432); (VH3-30*03 = SEQ ID NO: 545); (ADI-19112 = SEQ ID NO: 433); (ADI-19081 = SEQ ID NO: 409); (ADI-19109 = SEQ ID NO: 430); (ADI-19110 = SEQ ID NO: 431); (VH3-09*01 = SEQ ID NO: 546); (ADI-19092 = SEQ ID NO: 420); (ADI-19085 = SEQ ID NO: 413); (ADI-19090 = SEQ ID NO: 418); (ADI-19150 = SEQ ID NO: 419); (ADI-19147 = SEQ ID NO: 466); (ADI-19152 = SEQ ID NO: 470); (ADI-19132 = SEQ ID NO: 452); (ADI-19083 = SEQ ID NO: 411); (ADI-19148 = SEQ ID NO: 467); (ADI-19131 = SEQ ID NO: 451; (ADI-19151 = SEQ ID NO: 469); (ADI-19149 = SEQ ID NO: 468); (VH3-48*01 = SEQ ID NO: 547); (ADI-19088 = SEQ ID NO: 416); (VH3-21*01 = SEQ ID NO: 548); (ADI-19082 = SEQ ID NO: 410); (ADI-19113 = SEQ ID NO: 434); (ADI-19108 = SEQ ID NO: 429); (ADI-19101 = SEQ ID NO: 423); (ADI-19080 = SEQ ID NO: 408); (ADI-19114 = SEQ ID NO: 435); (VH3-23*01 = SEQ ID NO: 549);(ADI-19115 = SEQ ID NO: 436); and (ADI-19153 = SEQ ID NO: 471); [Figure 16]16A-16H show alignments of the light chain variable region sequences of various anti-TREM1 antibodies of the present disclosure. Figures 16A-16D show the CDR2 sequences from the light chain sequences, and Figures 16E-16H show the FR4 sequences from the remainder of the light chain sequences. (VK2-28*01 = SEQ ID NO: 550); (ADI-19131 = SEQ ID NO: 371); (ADI-19121 = SEQ ID NO: 363); (ADI-19123 = SEQ ID NO: 360); (ADI-19071 = SEQ ID NO: 320); (ADI-19074 = SEQ ID NO: 323); (ADI-19122 = SEQ ID NO: 364); (ADI-19117 = SEQ ID NO: 358); (ADI-19128 = SEQ ID NO: 368); (ADI-19072 = SEQ ID NO: 321); (ADI-19076 = SEQ ID NO: 324); (ADI- 19125 = SEQ ID NO: 365; (ADI-19077 = SEQ ID NO: 325); (ADI-19124 = SEQ ID NO: 361); (ADI-19148 = SEQ ID NO: 387); (ADI-19130 = SEQ ID NO: 370); (ADI-19078 = SEQ ID NO: 326); (ADI-19119 = SEQ ID NO: 359); (VK1-33*01 = SEQ ID NO: 551); (ADI-19068 = SEQ ID NO: 316); (ADI-19084 = SEQ ID NO: 332); (ADI-19104 = SEQ ID NO: 346); (VK1-05*01 = SEQ ID NO: 552; (ADI-19108 = SEQ ID NO: 349); (ADI-19153 = SEQ ID NO: 391); (VK1-05*03 = SEQ ID NO: 553); (ADI-19087 = SEQ ID NO: 335); (ADI-19127 = SEQ ID NO: 367); (ADI-19149 = SEQ ID NO: 388); (ADI-19090 = SEQ ID NO: 338); (ADI-19151 = SEQ ID NO: 389); (ADI-19085 = SEQ ID NO: 333); (ADI-19150 = SEQ ID NO: 339); (ADI-19126 = SEQ ID NO: 366);(VK1-12*03=SEQ ID NO:554);(ADI-19115=SEQ ID NO:356);(ADI-19146=SEQ ID NO:385);(ADI-19113=SEQ ID NO:354);(ADI-19103=SEQ ID NO:345);(ADI-19132=SEQ ID NO:372);(ADI-19107=SEQ ID NO:348);(ADI-19083=SEQ ID NO:331);(ADI-19147=SEQ ID NO:386);(ADI-19096=SEQ ID NO:334);(ADI-19145=SEQ ID NO:384);(VK1-39*01 = SEQ ID NO: 555); (ADI-19088 = SEQ ID NO: 336); (ADI-19139 = SEQ ID NO: 378); (ADI-19105 = SEQ ID NO: 347); (ADI-19097 = SEQ ID NO: 341); (ADI-19098 = SEQ ID NO: 342); (VK4-01*01 = SEQ ID NO: 556); (ADI-19133 = SEQ ID NO: 373); (ADI-19137 = SEQ ID NO: 376); (ADI-19081 = SEQ ID NO: 329); (ADI-19156 = SEQ ID NO: 394); (ADI- 19141 = SEQ ID NO: 380; (ADI-19069 = SEQ ID NO: 318); (ADI-19109 = SEQ ID NO: 350); (ADI-19140 = SEQ ID NO: 379); (ADI-19136 = SEQ ID NO: 375); (ADI-19120 = SEQ ID NO: 362); (ADI-19114 = SEQ ID NO: 355); (ADI-19112 = SEQ ID NO: 353); (ADI-19073 = SEQ ID NO: 322); (ADI-19110 = SEQ ID NO: 351); (ADI-19135 = SEQ ID NO: 374); (ADI-19142 = SEQ ID NO: 381; (ADI-19155 = SEQ ID NO: 393); (VK3-20*01 = SEQ ID NO: 557); (ADI-19138 = SEQ ID NO: 377); (ADI-19068 = SEQ ID NO: 317); (ADI-19089 = SEQ ID NO: 337); (ADI-19082 = SEQ ID NO: 330); (ADI-19080 = SEQ ID NO: 328); (ADI-19143 = SEQ ID NO: 382); (VK3-15*01 = SEQ ID NO: 558); (ADI-19116 = SEQ ID NO: 357); (ADI-19159 = SEQ ID NO: 395); (ADI-19154 = SEQ ID NO: 392); (ADI-19070 = SEQ ID NO: 319); (ADI-19101 = SEQ ID NO: 343); (ADI-19111 = SEQ ID NO: 352); (VK3-11*01 = SEQ ID NO: 559); (ADI-19152 = SEQ ID NO: 390); (ADI-19129 = SEQ ID NO: 369); (ADI-19079 = SEQ ID NO: 327); (ADI-19092 = SEQ ID NO: 340); (ADI-19092 = SEQ ID NO: 344); and (ADI-1944 = SEQ ID NO: 383); [Figure 17]Figure 1 provides data illustrating the identification of tumor types in humans likely to respond to Trem1 antibodies: CESC: cervical squamous cell carcinoma and endocervical adenocarcinoma; LGG: low-grade glioma of the brain; LIHC: hepatocellular carcinoma of the liver; LUSC: lung squamous cell carcinoma. DETAILED DESCRIPTION OF THE INVENTION

[0048] General technology The techniques and procedures described or referenced herein are generally well understood and may be found in, for example, Sambrook et al., Molecular Cloning: A Laboratory Manual, 3rd ed. (2001), Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY; Current Protocols in Molecular Biology (F.M. Ausubel et al., eds., (2003)); the series Methods in Enzymology (Academic Press, Inc.): PCR 2: A Practical Approach (M.J. MacPherson, B.D. Hames, and G.R. Taylor, eds. (1995)), Harlow and Lane, eds. (1988); Antibodies, A Laboratory Manual, and Animal Cell Culture (R.I. Freshney, ed. (1987)); Oligonucleotide Synthesis (M.J. Gait, ed., 1984); Methods in Molecular Biology, Humana Press; Cell Biology: A Laboratory Notebook (J.E. Cellis, ed., 1998) Academic Press; Animal Cell Culture (R.I. Freshney, ed., 1987); Introduction to Cell and Tissue Culture (JP Mather and PE Roberts, 1998) Plenum Press; Cell and Tissue Culture: Laboratory Procedures (A. Doyle, JB Griffiths and DG Newell, eds., 1993-8) J. Wiley & Sons; Handbook of Experimental Immunology (DM Weir and CC Blackwell, eds.); Gene Transfer Vectors for Mammalian Cells (JM Miller and MPCalos, 1987; PCR: The Polymerase Chain Reaction, (Mullis et al., 1994); Current Protocols in Immunology (J.E. Coligan et al., 1991); Short Protocols in Molecular Biology (Wiley and Sons, 1999); Immunobiology (C.A. Janeway and P. Travers, 1997); Antibodies (P. Finch, 1997); Antibodies: A Practical Approach (D. Catty, ed., IRL Press, 1988-1989); Monoclonal Antibodies: A Practical Approach (P. Shepherd and C. Dean, eds., Oxford University Press, 2000); Using Antibodies: A Laboratory Manual (E. Harlow and D. Lane, Cold Spring Harbor Laboratory Press, 1999); The Antibodies (M. Zanetti and J.D. Capra, eds., Harwood Academic Press, 1999) Publishers, 1995); as well as the widely used methodology described in Cancer: Principles and Practice of Oncology (eds. VT DeVita et al., JB Lippincott Company, 1993), are commonly employed by those skilled in the art using conventional methodologies.

[0049] definition As used herein, the term "preventing" includes providing prophylaxis with respect to the occurrence or recurrence of a particular disease, disorder or condition in an individual who may be predisposed to, susceptible to, or at risk of developing a particular disease, disorder or condition, but who has not yet been diagnosed with the disease, disorder or condition.

[0050] As used herein, an individual "at risk" of developing a particular disease, disorder, or condition may or may not have detectable disease or disease symptoms, and may or may not have exhibited detectable disease or disease symptoms prior to the treatments described herein. "At risk" indicates that an individual has one or more risk factors, which are measurable parameters that correlate with the development of a particular disease, disorder, or condition, as known in the art. Individuals with one or more of these risk factors have a higher likelihood of developing a particular disease, disorder, or condition than individuals without one or more of these risk factors.

[0051] As used herein, the term "treatment" refers to a clinical intervention designed to alter the natural course of the individual being treated during the course of clinical pathology. Desirable effects of treatment include slowing the rate of progression, ameliorating or alleviating the pathological state, and remission or improved prognosis of a particular disease, disorder, or condition. An individual is successfully "treated" if one or more symptoms associated with a particular disease, disorder, or condition are reduced or eliminated.

[0052] An "effective amount" refers to at least an amount effective, at dosages and for periods of time necessary, to achieve the desired therapeutic or prophylactic result. An effective amount can be provided in one or more administrations. As used herein, the effective amount can vary according to factors such as the individual's disease state, age, sex, and weight, and the ability of the treatment to elicit a desired response in the individual. An effective amount is also one in which the therapeutic beneficial effects outweigh the toxic or detrimental effects of the treatment. For prophylactic use, beneficial or desired results include results such as eliminating or reducing the risk, reducing the severity, or delaying the onset of the disease, including biochemical, histological, and / or behavioral manifestations of the disease, its complications, and intermediate pathological phenotypic manifestations during disease development. For therapeutic use, beneficial or desired results include clinical results such as reducing one or more symptoms caused by the disease, increasing the quality of life of those suffering from the disease, reducing the dose of other medications required to treat the disease, enhancing the effect of another medication by targeting, etc., delaying disease progression, and / or prolonging survival. An effective amount of a drug, compound, or pharmaceutical composition is an amount sufficient to achieve prophylactic or therapeutic treatment directly or indirectly. As understood in the clinical context, an effective amount of a drug, compound, or pharmaceutical composition may or may not be achieved in conjunction with another drug, compound, or pharmaceutical composition. Thus, an "effective amount" may be considered in the context of administering one or more therapeutic agents; a single agent may be considered to be administered in an effective amount if, together with one or more other agents, a desired result can be or is achieved.

[0053] A "therapeutically effective amount" is at least the minimum concentration required to achieve a measurable improvement in a particular disease, disorder, or condition. As used herein, a therapeutically effective amount may vary according to factors such as the patient's disease state, age, sex, and weight, and the ability of the anti-TREM1 antibody to elicit a desired response in the individual. A therapeutically effective amount is also one in which the therapeutically beneficial effects outweigh any toxic or detrimental effects of the anti-TREM1 antibody.

[0054] As used herein, administration "in combination with" another compound or composition includes simultaneous administration and / or administration at different times. Concomitant administration also encompasses administration as a co-formulation or as separate compositions, including at different dosing frequencies or intervals, using the same or different routes of administration.

[0055] An "individual" for purposes of treatment, risk prevention or reduction refers to any animal classified as a mammal, including domestic and farm animals, as well as zoo, sport or pet animals, such as humans, dogs, horses, rabbits, cows, pigs, hamsters, gerbils, mice, ferrets, rats, cats, etc. Preferably, the individual is a human.

[0056] The term "immunoglobulin" (Ig) is used interchangeably herein with "antibody." As used herein, the term "antibody" is used in the broadest sense to specifically cover monoclonal antibodies, polyclonal antibodies, multispecific antibodies (e.g., bispecific antibodies) formed from at least two intact antibodies, and antibody fragments so long as they exhibit the desired biological activity.

[0057] The basic four-chain antibody unit is a heterotetrameric glycoprotein composed of two identical light (L) chains and two identical heavy (H) chains. H and V L together form a single antigen-binding site. For the structure and properties of different classes of antibodies, see, e.g., Basic and Clinical Immunology, 8th ed., Daniel P. Stites, Abba I. Terr and Tristram G. Parslow (eds.), Appleton & Lange, Norwalk, CT, 1994, p. 71 and Chapter 6.

[0058] Light chains from any vertebrate species can be assigned to one of two clearly distinct types, called kappa ("κ") and lambda ("λ"), based on the amino acid sequence of their constant domains. Depending on the amino acid sequence of the constant domain (CH) of their heavy chains, immunoglobulins can be assigned to various classes or isotypes. There are five classes of immunoglobulins: IgA, IgD, IgE, IgG, and IgM, with heavy chains designated alpha ("α"), delta ("δ"), epsilon ("ε"), gamma ("γ"), and mu ("μ"), respectively. The gamma and alpha classes are further divided into subclasses (isotypes) based on relatively minor differences in CH sequence and function; for example, humans express the following subclasses: IgG1, IgG2, IgG3, IgG4, IgA1, and IgA2. The subunit structures and three-dimensional configurations of different classes of immunoglobulins are well known and are described generally in, for example, Abbas et al., Cellular and Molecular Immunology, 4th ed. (WB Saunders Co., 2000).

[0059] "Native antibodies" are usually heterotetrameric glycoproteins of about 150,000 daltons, composed of two identical light (L) chains and two identical heavy (H) chains. Each light chain is linked to a heavy chain by one covalent disulfide bond, although the number of disulfide linkages varies among the heavy chains of different immunoglobulin isotypes. Each heavy and light chain also has regularly spaced intrachain disulfide bridges. Each heavy chain contains at one end a variable domain (V H ) followed by several constant domains. Each light chain has at one end a variable domain (V L ) at one end and a constant domain at the other end, where the light chain constant domain is aligned with the first constant domain of the heavy chain and the light chain variable domain is aligned with the variable domain of the heavy chain. Particular amino acid residues are believed to form an interface between the light and heavy chain variable domains.

[0060] An "isolated antibody," such as an isolated anti-TREM1 antibody of the present disclosure, is one that has been identified, separated, and / or recovered (e.g., naturally or recombinantly) from components of its production environment. Preferably, an isolated polypeptide is free from association with all other contaminating components from its production environment. Contaminating components from its production environment, such as those resulting from recombinantly transfected cells, are materials that would normally interfere with research, diagnostic, or therapeutic uses of the antibody and may include enzymes, hormones, and other proteinaceous or non-proteinaceous solutes. In preferred embodiments, the polypeptide is purified to (1) greater than 95% by weight, and in some embodiments, greater than 99% by weight, of the antibody, as determined, for example, by the Lowry method; (2) sufficient to obtain at least 15 residues of N-terminal or internal amino acid sequence by use of a spinning cup sequenator; or (3) homogeneity by SDS-PAGE under non-reducing or reducing conditions using Coomassie blue or, preferably, silver staining. Isolated antibody includes the antibody in situ within recombinant T cells since at least one component of the antibody's natural environment will not be present. Ordinarily, however, isolated polypeptide or antibody will be prepared by at least one purification step.

[0061] The "variable region" or "variable domain" of an antibody, such as an anti-TREM1 antibody of the present disclosure, refers to the amino-terminal domains of the heavy or light chain of the antibody. The variable domains of the heavy and light chains, respectively, are referred to as "V H " and "V L These domains are generally the most variable parts of an antibody (relative to other antibodies of the same class) and contain the antigen-binding sites.

[0062] The term "variable" refers to the fact that certain segments of the variable domains vary significantly in sequence among antibodies, such as the anti-TREM1 antibodies of the present disclosure. V domains mediate antigen binding and define the specificity of a particular antibody for its particular antigen. However, variability is not uniformly distributed across the entire span of the variable domains. Instead, it is concentrated in three segments called hypervariable regions (HVRs) in both the light-chain and heavy-chain variable domains. The more highly conserved portions of the variable domains are called framework regions (FRs). Natural heavy-chain and light-chain variable domains each contain four FR regions that largely adopt a beta-sheet configuration, connected by three HVRs that form loops that connect, and in some cases form part of, the beta-sheet structure. The HVRs in each chain are held together in close proximity by the FR regions, and the HVRs of the other chains contribute to the formation of the antigen-binding site of antibodies (see Kabat et al., Sequences of Immunological Interest, 5th ed., National Institutes of Health, Bethesda, MD (1991)). The constant domains are not involved directly in binding an antibody to an antigen, but exhibit various effector functions, such as participation of the antibody in antibody-dependent cellular toxicity.

[0063] The terms "hypervariable region," "HVR," or "HV," as used herein, refer to regions of an antibody variable domain, such as those of the anti-TREM1 antibodies of the present disclosure, that are hypervariable in sequence and / or form structurally defined loops. Generally, antibodies contain six HVRs: three in the VH (H1, H2, and H3) and three in the VL (L1, L2, and L3). In natural antibodies, H3 and L3 are the most diverse of the six HVRs, and H3, in particular, is thought to play a unique role in conferring fine specificity to antibodies. See, e.g., Xu et al., Immunity 13:37-45 (2000); Johnson and Wu in Methods in Molecular Biology 248:1-25 (Lo, ed., Human Press, Totowa, NJ, 2003). In fact, naturally occurring camelid antibodies consisting only of heavy chains are functional and stable in the absence of light chains. See, for example, Hamers-Casterman et al., Nature 363:p446-448 (1993) and Sheriff et al., Nature Struct. Biol. 3:p733-736 (1996).

[0064] Several HVR delineations are in use and are encompassed herein. The Kabat complementarity-determining regions (CDRs) HVRs are based on sequence variability and are the most commonly used (Kabat et al., supra). Chothia instead refers to the location of structural loops (Chothia and Lesk J. Mol. Biol. 196:901-917 (1987)). The AbM HVRs represent a compromise between the Kabat CDRs and the Chothia structural loops and are used by Oxford Molecular's AbM antibody modeling software. The "contact" HVRs are based on an analysis of available complex crystal structures. Residues from each of these HVRs are listed below. TIFF2024119791000002.tif79170

[0065] HVRs may include "extended HVRs" as follows: 24-36 or 24-34 (L1), 46-56 or 50-56 (L2) and 89-97 or 89-96 (L3) in VL and 26-35 (H1), 50-65 or 49-65 (preferred embodiment) (H2) and 93-102, 94-102 or 95-102 (H3) in VH. The variable domain residues are numbered according to Kabat et al., supra, for each of these extended HVR definitions.

[0066] "Framework" or "FR" residues are those variable domain residues other than the HVR residues as herein defined.

[0067] The phrases "variable domain residue numbering as in Kabat" or "amino acid position numbering as in Kabat" and variations thereof refer to the numbering system used for the heavy or light chain variable domains of a compilation of antibodies in Kabat et al., supra. Using this numbering system, the actual linear amino acid sequence may contain fewer or additional amino acids corresponding to a shortening of, or insertion into, the FRs or HVRs of the variable domain. For example, a heavy chain variable domain may contain a single amino acid insertion after residue 52 of H2 (residue 52a according to Kabat) and inserted residues after heavy chain FR residue 82 (e.g., residues 82a, 82b, and 82c, etc., according to Kabat). The Kabat numbering of residues can be determined for a given antibody by alignment with the "standard" Kabat numbered sequence at regions of antibody sequence homology.

[0068] The Kabat numbering system is commonly used when referring to residues in the variable domain (approximately residues 1-107 of the light chain and 1-113 of the heavy chain) (e.g., Kabat et al., Sequences of Immunological Interest. 5th ed. Public Health Service, National Institutes of Health, Bethesda, Md. (1991)). The terms "EU or Kabat numbering system" or "EU index" are commonly used when referring to residues in the immunoglobulin heavy chain constant region (e.g., the EU index reported in Kabat et al., supra). "EU index as in Kabat" refers to the residue numbering of the human IgG1 EU antibody. References to residue numbering in the variable domain of an antibody refer to residue numbering according to the Kabat numbering system. References to residue numbers in the constant domain of an antibody refer to residue numbering according to the EU or Kabat numbering system (see, e.g., U.S. Patent Publication No. 2010-280227).

[0069] An "acceptor human framework," as used herein, is a framework comprising the amino acid sequence of a VL or VH framework derived from a human immunoglobulin framework or a human consensus framework. An acceptor human framework "derived from" a human immunoglobulin framework or a human consensus framework may comprise the identical amino acid sequence or may contain pre-existing amino acid sequence changes. In some embodiments, the number of pre-existing amino acid changes is 10 or less, 9 or less, 8 or less, 7 or less, 6 or less, 5 or less, 4 or less, 3 or less, or 2 or less. When pre-existing amino acid changes are present in the VH, preferably those changes occur at only three, two, or one of positions 71H, 73H, and 78H; for example, the amino acid residues at those positions may be 71A, 73T, and / or 78A. In one embodiment, the VL acceptor human framework is identical in sequence to the VL human immunoglobulin framework sequence or the human consensus framework sequence.

[0070] A "human consensus framework" is a framework that represents the most commonly occurring amino acid residues in a selection of human immunoglobulin VL or VH framework sequences. Generally, the selection of human immunoglobulin VL or VH sequences is from a subgroup of variable domain sequences. Generally, the subgroup of sequences is a subgroup as in Kabat et al., Sequences of Proteins of Immunological Interest, 5th ed., Public Health Service, National Institutes of Health, Bethesda, MD (1991). By way of example, for VL, the subgroup may be subgroup kappa I, kappa II, kappa III, or kappa IV as in Kabat et al., supra. Furthermore, for VH, the subgroup may be subgroup I, subgroup II, or subgroup III as in Kabat et al., supra.

[0071] The term "monoclonal antibody," as used herein, refers to an antibody, such as a monoclonal anti-TREM1 antibody of the present disclosure, obtained from a population of substantially homogeneous antibodies, i.e., the individual antibodies comprising the population are identical except for possible naturally occurring mutations and / or minor post-translational modifications (e.g., isomerization, amidation, etc.). Monoclonal antibodies are highly specific, being directed against a single antigenic site. In contrast to polyclonal antibody preparations, which typically include different antibodies directed against different determinants (epitopes), each monoclonal antibody is directed against a single determinant on the antigen. In addition to their specificity, monoclonal antibodies are advantageous in that they are synthesized by a hybridoma culture, uncontaminated by other immunoglobulins. The modifier "monoclonal" indicates the character of the antibody as being obtained from a substantially homogeneous population of antibodies and should not be construed as requiring production of the antibody by any particular method. For example, monoclonal antibodies to be used in accordance with the present invention can be produced using, for example, hybridoma techniques (e.g., Kohler and Milstein, Nature, 256:495-97 (1975); Hongo et al., Hybridoma, 14(3):253-260 (1995); Harlow et al., Antibodies: A Laboratory Manual, (Cold Spring Harbor Laboratory Press, 2nd ed. 1988); Hammerling et al., in: Monoclonal Antibodies and T-Cell Hybridomas 563-681 (Elsevier, NY, 1981)), recombinant DNA techniques (see, e.g., U.S. Pat. No. 4,816,567), phage display techniques (e.g., Clackson et al., Nature, 352:624-628 (1991); Marks et al., J. Mol. Biol. 222:581-597 (1992); Sidhu et al., J. Mol. Biol. 338(2):299-310(2004); Lee et al., J. Mol. Biol. 340(5):1073-1093(2004); Fellouse, Proc. Nat'l Acad. Sci. USA 101(34):12467-472(2004); and Lee et al., J.Immunol. Methods 284(1-2):119-132 (2004), as well as techniques for producing human or human-like antibodies in animals that have some or all of the human immunoglobulin loci or genes encoding human immunoglobulin sequences (e.g., WO 1998 / 24893; WO 1996 / 34096; WO 1996 / 33735; WO 1991 / 10741; Jakobovits et al., Proc. Nat'l Acad. Sci. USA 90:2551 (1993); Jakobovits et al., Nature 362:255-258 (1993); Bruggemann et al., Year in Immunol. 7:33 (1993); U.S. Patent Nos. 5,545,807; 5,545,806; 5,569,825; 5,625,126; 5,633,425; and 5,661,016; Marks et al., Bio / Technology 10:779-783 (1992); Lonberg et al., Nature 368:856-859 (1994); Morrison, Nature 368:812-813 (1994); Fishwild et al., Nature Biotechnol. 14:845-851 (1996); Neuberger, Nature Biotechnol. 14:826 (1996); and Lonberg and Huszar, Intern. Rev. Immunol. 13:65-93 (1995)).

[0072] The terms "full length antibody," "intact antibody," or "whole antibody" are used interchangeably and refer to an antibody, such as an anti-TREM1 antibody of the present disclosure, in its substantially intact form, as opposed to an antibody fragment. Specifically, whole antibodies include those having heavy and light chains, including an Fc region. The constant domains may be native sequence constant domains (e.g., human native sequence constant domains) or amino acid sequence variants thereof. In some cases, an intact antibody may have one or more effector functions.

[0073] An "antibody fragment" comprises a portion of an intact antibody, preferably the antigen-binding and / or variable region of the intact antibody. Examples of antibody fragments include Fab, Fab', F(ab')2, and Fv fragments, diabodies, linear antibodies (see U.S. Pat. No. 5,641,870, Example 2; Zapata et al., Protein Eng. 8(10):1057-1062 (1995)), single-chain antibody molecules, and multispecific antibodies formed from antibody fragments.

[0074] Papain digestion of an antibody, such as the anti-TREM1 antibody of the present disclosure, results in two identical antigen-binding fragments, called "Fab" fragments, and a residual "Fc" fragment, a name reflecting their ability to readily crystallize. The Fab fragment contains the variable region domain of the heavy chain (V H ) and the first constant domain of one heavy chain (C H Fab fragments consist of an entire L chain together with the Fab fragment (i.e., the Fab fragments have a single antigen-binding site). Each Fab fragment is monovalent with respect to antigen binding, i.e., it has a single antigen-binding site. Pepsin treatment of an antibody yields a single large F(ab')2 fragment which roughly corresponds to two disulfide-linked Fab fragments with different antigen-binding activities and is still capable of cross-linking antigen. The Fab' fragment contains one or more cysteines from the antibody hinge region, C(ab')2. H F(ab')2 antibody fragments differ from Fab fragments by having a few additional residues at the carboxy terminus of one domain. Fab'-SH is the designation herein for Fab' in which the cysteine ​​residue(s) in the constant domains bear a free thiol group. F(ab')2 antibody fragments originally were produced as pairs of Fab' fragments which have hinge cysteines between them. Other chemical couplings of antibody fragments are also known.

[0075] The Fc fragment contains the carboxy-terminal portions of both heavy chains held together by disulfides. The effector functions of an antibody are determined by sequences in the Fc region, the region that is also recognized by Fc receptors (FcRs) found on certain types of cells.

[0076] An "Fv" is the minimum antibody fragment containing a complete antigen-recognition and antigen-binding site. This fragment consists of a dimer of one heavy- and one light-chain variable region domain in tight, non-covalent association. Folding of these two domains results in six HVRs (three loops from each of the H and L chains) that contribute amino acid residues for antigen binding and confer antigen-binding specificity to the antibody. However, even a single variable domain (or half of an Fv containing only three HVRs specific for an antigen) has the ability to recognize and bind antigen, albeit with lower affinity than the entire binding site.

[0077] "Single-chain Fv" is also abbreviated as "sFv" or "scFv" and refers to a VFv fragment connected to a single polypeptide chain. H and V L Preferably, the sFv polypeptide is an antibody fragment containing a V domain that enables the sFv to form the desired structure for antigen binding. H and V L It further comprises a polypeptide linker between the domains. For a review of sFvs, see Pluckthun in The Pharmacology of Monoclonal Antibodies, Vol. 113, Rosenburg and Moore (eds.), Springer-VerLAG-3, New York, pp. 269-315 (1994).

[0078] A "functional fragment" of an antibody, such as the anti-TREM1 antibody of the present disclosure, comprises a portion of an intact antibody, generally comprising the antigen-binding or variable region of the intact antibody or the F region of the antibody that retains or has modified FcR binding ability. Examples of antibody fragments include linear antibodies, single-chain antibody molecules, and multispecific antibodies formed from antibody fragments.

[0079] The term "diabody" refers to a diabody formed by combining V domains such that interchain, but not intrachain, pairing of the V domains is achieved, thereby resulting in a bivalent fragment, i.e., a fragment with two antigen-binding sites. H and V Lrefers to small antibody fragments prepared by constructing sFv fragments (see previous paragraph) with a short linker (about 5-10 residues) between the domains. Bispecific diabodies are small antibody fragments prepared by constructing sFv fragments (see previous paragraph) with a short linker (about 5-10 residues) between the domains. H and V L Diabodies are heterodimers of two "crossover" sFv fragments, whose domains are present on different polypeptide chains. Diabodies are described in more detail in, for example, EP 404,097; WO 93 / 11161; Hollinger et al., Proc. Nat'l Acad. Sci. USA 90:6444-48 (1993).

[0080] As used herein, the term "chimeric antibody" refers to antibodies (immunoglobulins), such as the chimeric anti-TREM1 antibodies of the present disclosure, in which a portion of the heavy and / or light chain is identical to or homologous to corresponding sequences in antibodies derived from a particular species or belonging to a particular antibody class or subclass, and the remainder of the chains (both chains) are identical to or homologous to corresponding sequences in antibodies derived from another species or belonging to another antibody class or subclass, as well as fragments of such antibodies, so long as they exhibit the desired biological activity (U.S. Pat. No. 4,816,567; Morrison et al., Proc. Nat'l Acad. Sci. USA, 81:6851-55 (1984)). Chimeric antibodies of interest herein include, for example, PRIMATIZED® antibodies, in which the antigen-binding region of the antibody is derived from an antibody produced by immunizing macaque monkeys with an antigen of interest. As used herein, the term "humanized antibody" is a subset of the term "chimeric antibody."

[0081] "Humanized" forms of non-human (e.g., murine) antibodies, such as humanized forms of the anti-TREM1 antibodies of the present disclosure, are chimeric antibodies that contain minimal sequence derived from non-human immunoglobulin. In one embodiment, a humanized antibody is a human immunoglobulin (recipient antibody) in which residues from an HVR of the recipient are replaced by residues from an HVR of a non-human species (donor antibody) such as mouse, rat, rabbit, or non-human primate having the desired specificity, affinity, and / or capacity. In some instances, FR residues of the human immunoglobulin are replaced by corresponding non-human residues. Furthermore, humanized antibodies may comprise residues that are not found in the recipient antibody or in the donor antibody. These modifications may be made to further improve antibody performance, such as binding affinity. Generally, a humanized antibody will comprise substantially all of at least one, and usually two, variable domains, in which all or substantially all of the hypervariable loops correspond to those of a non-human immunoglobulin sequence, and all or substantially all of the FR regions are those of a human immunoglobulin sequence, although the FR regions may comprise one or more individual FR residue substitutions which improve antibody performance, such as binding affinity, isomerization, immunogenicity, etc. The number of these amino acid substitutions in the FRs will typically be no more than six in the H chain and no more than three in the L chain. The humanized antibody also optionally comprises at least a portion of an immunoglobulin constant region (Fc), typically that of a human immunoglobulin. For further details, see, e.g., Jones et al., Nature 321:522-525 (1986); Riechmann et al., Nature 332:323-329 (1988); and Presta, Curr. Op. Struct. Biol. 2:593-596 (1992). See also, e.g., Vaswani and Hamilton, Ann. Allergy, Asthma & Immunol. 1:105-115 (1998); Harris, Biochem. Soc. Transactions 23:1035-1038 (1995); Hurle and Gross, Curr. Op. Biotech. 5:428-433 (1994); and U.S. Patent Nos. 6,982,321 and 7,087,409.

[0082] A "human antibody" is one having an amino acid sequence corresponding to that of an antibody, such as the anti-TREM1 antibody of the present disclosure, that has been produced by a human and / or that has been produced using any of the techniques for producing human antibodies as disclosed herein. This definition of human antibody specifically excludes humanized antibodies that contain non-human antigen-binding residues. Human antibodies can be produced using a variety of techniques known in the art, including phage display libraries. Hoogenboom and Winter, J. Mol. Biol., 227:381 (1991); Marks et al., J. Mol. Biol., 222:581 (1991). Also available for preparing human monoclonal antibodies are methods described in Cole et al., Monoclonal Antibodies and Cancer Therapy, Alan R. Liss, p. 77 (1985); Boerner et al., J. Immunol., 147(1):86-95 (1991). See also van Dijk and van de Winkel, Curr. Opin. Pharmacol. 5:368-74 (2001). Human antibodies can be prepared by administering antigen to transgenic animals, e.g., immunized xenomice, which have been modified to produce such antibodies in response to antigen challenge but whose endogenous gene loci have been disabled (see, e.g., U.S. Pat. Nos. 6,075,181 and 6,150,584 regarding XENOMOUSE™ technology). See also, e.g., Li et al., Proc. Nat'l Acad. Sci. USA 103:3557-3562 (2006), regarding human antibodies generated by human B-cell hybridoma technology.

[0083] For example, an "amino acid modification" at a particular position of an anti-TREM1 antibody of the present disclosure refers to a substitution or deletion of the particular residue or an insertion of at least one amino acid residue adjacent to the particular residue. An insertion "adjacent to" a particular residue means an insertion within 1-2 residues thereof. The insertion may be at the N-terminus or C-terminus of the particular residue. A preferred amino acid modification herein is a substitution.

[0084] An "affinity matured" antibody, such as an affinity matured anti-TREM1 antibody of the present disclosure, is one that contains one or more alterations in one or more of its HVRs that result in an improvement in the affinity of the antibody for antigen compared to a parent antibody that does not possess those alteration(s). In one embodiment, the affinity matured antibody has nanomolar or even picomolar affinity for the target antigen. Affinity matured antibodies are produced by procedures known in the art. For example, Marks et al., Bio / Technology 10:779-783 (1992) describes affinity maturation by VH- and VL-domain shuffling. Random mutagenesis of HVR and / or framework residues has been described, for example, by Barbas et al., Proc. Nat. Acad. Sci. USA 91:3809-3813 (1994); Schier et al., Gene 169:147-155 (1995); Yelton et al., J. Immunol. 155:1994-2004 (1995); Jackson et al., J. Immunol. 154(7):3310-9 (1995); and Hawkins et al., J. Mol. Biol. 226:889-896 (1992).

[0085] As used herein, the terms "specifically recognize" or "specifically bind" refer to a measurable, reproducible interaction, such as attraction or binding, between a target and an antibody, such as between an anti-TREM1 antibody and TREM1, that determines the presence of the target in the presence of a heterogeneous population of molecules, including biomolecules. For example, an antibody, such as the anti-TREM1 antibody of the present disclosure, that specifically or preferentially binds to a target or epitope is an antibody that binds to this target or epitope with greater affinity, avidity, more readily, and / or for a longer period of time than it binds to other targets or other epitopes of the target. For example, it is understood by reading this definition that an antibody (or moiety) that specifically or preferentially binds to a first target may or may not specifically or preferentially bind to a second target. Thus, "specific binding" or "preferential binding" does not necessarily require (but can include) exclusive binding. An antibody that specifically binds to a target has at least about 10 3 M -1 or 10 4 M -1 , sometimes about 10 5 M -1 or 10 6 M -1 , in other cases, about 10 6 M -1 or 10 7 M -1 , about 10 8 M -1 -10 9 M -1 or about 10 10 M -1 -10 11 M -1or higher. A variety of immunoassay formats can be used to select antibodies specifically immunoreactive with a particular protein. For example, solid-phase ELISA immunoassays are routinely used to select monoclonal antibodies specifically immunoreactive with a protein. See, e.g., Harlow and Lane (1988) Antibodies, A Laboratory Manual, Cold Spring Harbor Publications, New York, for a description of immunoassay formats and conditions that can be used to determine specific immunoreactivity.

[0086] As used herein, an "interaction" between a TREM1 protein or a DAP12 protein and a second protein includes, but is not limited to, a protein-protein interaction, a physical interaction, a chemical interaction, a bond, a covalent bond, and an ionic bond. As used herein, an antibody "inhibits the interaction" between two proteins if the antibody disrupts, reduces, or completely eliminates the interaction between the two proteins. An antibody or fragment thereof of the present disclosure "inhibits the interaction" between two proteins if the antibody or fragment thereof binds to one of the two proteins.

[0087] An "agonist" or "activating" antibody is an antibody, such as an agonist anti-TREM1 antibody of the present disclosure, that induces (e.g., increases) one or more activities or functions of an antigen after the antibody binds to the antigen.

[0088] An "antagonist" or "blocking" antibody is an antibody, such as an antagonist anti-TREM1 antibody of the present disclosure, that reduces or eliminates (e.g., decreases) antigen binding to one or more ligands and / or reduces or eliminates (e.g., decreases) one or more activities or functions of the antigen after the antibody binds to the antigen. In some embodiments, an antagonist or blocking antibody substantially or completely inhibits antigen binding to one or more ligands and / or one or more activities or functions of the antigen.

[0089] Antibody "effector" functions refer to those biological activities attributable to the Fc region (a native sequence Fc region or amino acid sequence variant Fc region) of an antibody, and vary depending on the antibody isotype.

[0090] As used herein, the term "Fc region" is used to define the C-terminal region of an immunoglobulin heavy chain, including native-sequence Fc regions and variant Fc regions. Although the boundaries of the Fc region of an immunoglobulin heavy chain might vary, the human IgG heavy chain Fc region is usually defined to stretch from position Cys226, or from Pro230, to the carboxyl-terminus. The C-terminal lysine of the Fc region (residue 447 according to the EU or Kabat numbering system) can be removed, for example, during antibody production or purification, or by recombinantly engineering the nucleic acid encoding the antibody heavy chain. Thus, a composition of intact antibodies can include antibody populations in which all K447 residues have been removed, antibody populations in which the K447 residue has not been removed, and antibody populations having a mixture of antibodies with and without the K447 residue. Suitable native-sequence Fc regions for use in the antibodies of the present disclosure include human IgG1, IgG2, IgG3, and IgG4.

[0091] A "native sequence Fc region" comprises an amino acid sequence identical to that of an Fc region found in nature. Native sequence human Fc regions include native sequence human IgG1 Fc regions (non-A and A allotypes), native sequence human IgG2 Fc regions, native sequence human IgG3 Fc regions, and native sequence human IgG4 Fc regions, as well as naturally occurring variants thereof.

[0092] A "variant Fc region" comprises an amino acid sequence that differs from that of a native-sequence Fc region by virtue of at least one amino acid modification, preferably one or more amino acid substitutions. Preferably, the variant Fc region has at least one amino acid substitution, e.g., about one to about ten amino acid substitutions, preferably about one to about five amino acid substitutions, in the native-sequence Fc region or in the Fc region of the parent polypeptide, compared to the native-sequence Fc region or to the Fc region of the parent polypeptide. As used herein, a variant Fc region preferably has at least about 80% identity with the native-sequence Fc region and / or to the Fc region of the parent polypeptide, most preferably at least about 90% identity thereto, and more preferably at least about 95% identity thereto.

[0093] "Fc receptor" or "FcR" describes a receptor that binds to the Fc region of an antibody. A preferred FcR is a native-sequence human FcR. Further, a preferred FcR is one that binds an IgG antibody (a gamma receptor) and includes receptors of the FcγRI, FcγRII, and FcγRIII subclasses (including allelic variants or splice forms of these receptors). FcγRII receptors include FcγRIIA (an "activating receptor") and FcγRIIB (an "inhibiting receptor"), which have similar amino acid sequences that differ primarily in their cytoplasmic domains. Activating receptor FcγRIIA contains an immunoreceptor tyrosine-based activation motif ("ITAM") in its cytoplasmic domain. Inhibiting receptor FcγRIIB contains an immunoreceptor tyrosine-based inhibition motif ("ITIM") in its cytoplasmic domain (see, e.g., M. Daeron, Annu. Rev. Immunol. 15:203-234 (1997)). FcRs are reviewed in Ravetch and Kinet, Annu. Rev. Immunol. 9:457-92 (1991); Capel et al., Immunomethods 4:25-34 (1994); and de Haas et al., J. Lab. Clin. Med. 126:330-41 (1995). Other FcRs, including those identified in the future, are encompassed by the term "FcR" herein. FcRs may also increase the serum half-life of antibodies.

[0094] The in vivo FcRn binding and serum half-life of human FcRn high-affinity-binding polypeptides can be assayed, for example, in transgenic mice or transfected human cell lines expressing human FcRn, or in primates to which polypeptides having mutant Fc regions have been administered. International Publication No. WO 2004 / 42072 (Presta) describes antibody mutants with improved or diminished FcR binding. See also, for example, Shields et al., J. Biol. Chem. 9(2):6591-6604 (2001).

[0095] As used herein, "percent (%) amino acid sequence identity" and "homology" with respect to peptide, polypeptide, or antibody sequences refer to the percentage of amino acid residues in a candidate sequence that are identical to those in a specific peptide or polypeptide sequence, after aligning the sequences and introducing gaps, if necessary, to achieve the maximum percent sequence identity, without considering any conservative substitutions as part of the sequence identity. Alignment for purposes of determining percent amino acid sequence identity can be achieved in a variety of ways that are within the skill of the art, for example, using publicly available computer software such as BLAST, BLAST-2, ALIGN, or MEGALIGN™ (DNASTAR) software. Those skilled in the art can determine appropriate parameters for measuring alignment, including any algorithms known in the art required to achieve maximal alignment over the full length of the sequences being compared. An amino acid residue "corresponds" to another amino acid residue present in a reference sequence when the sequence of interest and the reference sequence are maximally aligned.

[0096] An "isolated" nucleic acid molecule encoding an antibody, such as the anti-TREM1 antibody of the present disclosure, is a nucleic acid molecule that has been identified and separated from at least one contaminant nucleic acid molecule with which it is normally associated in the environment in which it is produced. Preferably, an isolated nucleic acid is free from association with all components associated with the production environment. Isolated nucleic acid molecules encoding the polypeptides and antibodies herein are in a form other than the form or setting in which they are found in nature. Thus, isolated nucleic acid molecules are distinguished from nucleic acids encoding the polypeptides and antibodies herein that naturally occur in a cell.

[0097] The term "vector" as used herein refers to a nucleic acid molecule capable of transporting another nucleic acid to which it has been linked. One type of vector is a "plasmid," which refers to a circular double-stranded DNA into which additional DNA segments can be ligated. Another type of vector is a phage vector. Another type of vector is a viral vector, into which additional DNA segments can be ligated. Certain vectors are capable of autonomous replication in a host cell into which they are introduced (e.g., bacterial vectors having a bacterial origin of replication and episomal mammalian vectors). Other vectors (e.g., non-episomal mammalian vectors) can be integrated into the genome of a host cell upon introduction into the host cell, and thereby are replicated along with the host genome. Moreover, certain vectors are capable of directing the expression of genes to which they are operably linked. Such vectors are referred to herein as "recombinant expression vectors" or simply "expression vectors." In general, expression vectors useful in recombinant DNA techniques are often in the form of plasmids. As used herein, "plasmid" and "vector" can be used interchangeably with plasmid, which is the most commonly used form of vector.

[0098] "Polynucleotide" or "nucleic acid," as used interchangeably herein, refer to a polymer of nucleotides of any length, and include DNA and RNA. The nucleotides can be deoxyribonucleotides, ribonucleotides, modified nucleotides or bases, and / or their analogs, or any substrate that can be incorporated into a polymer by DNA or RNA polymerase or by a synthetic reaction. A polynucleotide can contain modified nucleotides, such as methylated nucleotides and their analogs. If present, modifications to the nucleotide structure can be imparted before or after assembly of the polymer. The sequence of nucleotides can be interrupted by non-nucleotide components. A polynucleotide can include modifications performed after synthesis, such as conjugation with a label. Other types of modifications include, for example, "caps," substitution of one or more naturally occurring nucleotides with analogs, e.g., those with uncharged linkages (e.g., methylphosphonates, phosphotriesters, phosphoamidates, carbamates, etc.) and those with charged linkages (e.g., phosphorothioates, phosphorodithioates, etc.), those containing pendant moieties such as proteins (e.g., nucleases, toxins, antibodies, signal peptides, ply-L-lysine, etc.), those with internucleotide modifications (e.g., acridine, psoralen, etc.), those containing chelators (e.g., metals, radioactive metals, boron, metal oxides, etc.), those containing alkylating agents, those with modified linkages (e.g., alpha-anomeric nucleic acids, etc.), and unmodified forms of polynucleotide(s). Additionally, any of the hydroxyl groups normally present in the sugar can be replaced, for example, by a phosphonate group, a phosphate group, protected by a standard protecting group, or activated to prepare further linkages with additional nucleotides, or conjugated to a solid or semi-solid support. The 5' and 3' terminal OH can be phosphorylated or substituted with amines or organic capping group moieties of 1-20 carbon atoms. Other hydroxyls can also be derivatized to standard protecting groups.Polynucleotides may also contain analogous forms of ribose or deoxyribose sugars commonly known in the art, including, for example, 2'-O-methyl-, 2'-O-allyl-, 2'-fluoro-, or 2'-azido-ribose, carbocyclic sugar analogs, α-anomeric sugars, epimeric sugars such as arabinose, xylose, or lyxose, pyranose sugars, furanose sugars, sedoheptuloses, acyclic analogs, and basic nucleoside analogs such as methyl riboside. One or more phosphodiester linkages may be replaced by alternative linking groups. These alternative linking groups include, but are not limited to, embodiments in which phosphate is replaced by P(O)S ("thioate"), P(S)S ("dithioate"), (O)NR2 ("amidate"), P(O)R, P(O)OR', CO, or CH2 ("formacetal"), where each R or R' is independently H or substituted or unsubstituted alkyl (1-20 C), aryl, alkenyl, cycloalkyl, cycloalkenyl, or araldyl, optionally containing an ether (-O-) linkage. Not all linkages in a polynucleotide need be identical. The foregoing description applies to all polynucleotides referred to herein, including RNA and DNA.

[0099] A "host cell" includes an individual cell or cell culture that can be, or has been, the recipient of a vector(s) for incorporation of a polynucleotide insert. A host cell includes the progeny of a single host cell, which progeny may not necessarily be completely identical (in morphology or in genomic DNA complement) to the original parent cell due to natural, accidental, or deliberate mutation. A host cell includes cells transfected in vivo with a polynucleotide(s) of the invention.

[0100] As used herein, the term "carrier" includes pharmaceutically acceptable carriers, excipients, or stabilizers that are nontoxic to cells or mammals exposed thereto at the dosages and concentrations employed. Physiologically acceptable carriers are often aqueous pH-buffered solutions. Examples of physiologically acceptable carriers include buffers such as phosphate, citrate, and other organic acids; antioxidants, including ascorbic acid; low molecular weight (less than about 10 residues) polypeptides; proteins, such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers, such as polyvinylpyrrolidone; amino acids, such as glycine, glutamine, asparagine, arginine, or lysine; monosaccharides, disaccharides, and other carbohydrates, including glucose, mannose, or dextrins; chelating agents, such as EDTA; sugar alcohols, such as mannitol or sorbitol; salt-forming counterions, such as sodium; and / or nonionic surfactants, such as TWEEN™, polyethylene glycol (PEG), and PLURONICS™.

[0101] The term "about" is used herein to refer to the normal error range for the respective value, which is readily known to one of ordinary skill in the art. Reference herein to "about" a value or parameter includes (and describes) embodiments directed to that value or parameter itself.

[0102] As used herein and in the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. For example, reference to "an antibody" is a reference to one to many antibodies, such as molar amounts, and includes equivalents thereof known to those skilled in the art, and so forth.

[0103] It is understood that the aspects and embodiments of the present disclosure described herein include "comprising," "consisting of," and "consisting essentially of" aspects and embodiments.

[0104] overview The present disclosure relates to anti-TREM1 antibodies having one or more agonist or antagonist activities, methods of making and using such antibodies, pharmaceutical compositions containing such antibodies, nucleic acids encoding such antibodies, and host cells containing nucleic acids encoding such antibodies.

[0105] In some embodiments, the agonist activity of an anti-TREM1 antibody of the present disclosure is due, at least in part, to the ability of the antibody to enhance one or more TREM1 activities induced by the binding of one or more TREM1 ligands to the TREM1 protein without competing with or otherwise blocking the binding of the one or more TREM1 ligands to the TREM1 protein. In some embodiments, the enhancement of one or more TREM1 activities by the anti-TREM1 antibody is compared to one or more TREM1 activities induced by the binding of one or more TREM1 ligands to the TREM1 protein in the absence of the anti-TREM1 antibody. In some embodiments, the enhancement of one or more TREM1 activities can be determined or tested in vitro or in vivo by any of several techniques disclosed herein (see, e.g., Table 1B).

[0106] Accordingly, certain aspects of the present disclosure are based, at least in part, on the identification of anti-TREM1 antibodies that are capable of binding to human TREM1 with high affinity (see, e.g., Table 1A) and that can activate and enhance TREM1 activity (e.g., by cooperating with a TREM1 ligand) (see, e.g., Table 1B).

[0107] Further aspects of the present disclosure are based, at least in part, on the surprising discovery that the anti-TREM1 antibodies of the present disclosure can also induce antagonist activity when the antibodies are produced or otherwise formatted such that they are unable to induce or maintain TREM1 receptor clustering. In some embodiments, the anti-TREM1 antibodies of the present disclosure exhibit one or more antagonist TREM1 activities, including, but not limited to, inhibition of TREM1-dependent gene activation (see, e.g., Table 1B).

[0108] TREM1 protein In one aspect, the present disclosure provides an antibody that binds to a TREM1 protein of the present disclosure and induces and / or enhances one or more TREM1 activities after binding to a TREM1 protein expressed in a cell. TREM1 is a 234-amino acid immunoglobulin-like receptor membrane protein primarily expressed in myeloid lineage cells, including, but not limited to, macrophages, dendritic cells, monocytes, dermal Langerhans cells, Kupffer cells, osteoclasts, neutrophils, and microglia. In some instances, TREM1 forms a receptor signaling complex with DAP12. In some instances, TREM1 can phosphorylate and signal through DAP12 (an ITAM domain adaptor protein). TREM1 signaling can result in downstream activation of PI3K or other intracellular signals. In myeloid cells, Toll-like receptor (TLR) signaling is important for activating TREM1 activity, for example, in the context of an infection response. TLRs, such as those expressed on macrophages and dendritic cells, also play an important role in pathological inflammatory responses.

[0109] TREM1 proteins of the present disclosure include, but are not limited to, mammalian TREM1 proteins, human TREM1 proteins (Uniprot accession number Q9NP99, SEQ ID NO: 1), mouse TREM1 proteins (Uniprot accession number Q9JKE2, SEQ ID NO: 2), rat TREM1 proteins (Uniprot accession number D4ABU7, SEQ ID NO: 3), rhesus monkey TREM1 proteins (Uniprot accession number F6TBB4, SEQ ID NO: 4), bovine TREM1 proteins (Uniprot accession number Q6QUN5, SEQ ID NO: 5), equine TREM1 proteins (Uniprot accession number F6PSF7, SEQ ID NO: 6), porcine TREM1 proteins (Uniprot accession number R4SEY7, SEQ ID NO: 7), chimpanzee TREM1 proteins (Uniprot accession number H2QSZ3, SEQ ID NO: 561), and dog TREM1 proteins (Uniprot accession number E2RP37, SEQ ID NO: 8). As used herein, "TREM1 protein" refers to both the wild-type sequence and naturally occurring mutant sequences.

[0110] An example of a human TREM1 amino acid sequence is shown below as SEQ ID NO: 1: TIFF2024119791000003.tif54170

[0111] Human TREM1 may be in a precursor protein form that includes a signal peptide. In some embodiments, human TREM1 is a mature protein that does not include a signal peptide. In some embodiments, the mature TREM1 protein is expressed in a cell. An exemplary human TREM1 protein (portein) may contain a signal peptide located at amino acid residues 1-25 of human TREM1 (SEQ ID NO: 1), an extracellular immunoglobulin-like variable (IgV) domain located at amino acid residues 26-134 of human TREM1 (SEQ ID NO: 1), an additional extracellular sequence located at amino acid residues 135-205 of human TREM1 (SEQ ID NO: 1), a transmembrane domain located at amino acid residues 227-234 of human TREM1 (SEQ ID NO: 1), and an intracellular domain located at amino acid residues 227-234 of human TREM1 (SEQ ID NO: 1).

[0112] The transmembrane domain of human TREM1 contains a lysine at amino acid residue 217 that can interact with an aspartate in DAP12, a key adaptor protein that transmits signaling from TREM2, TREM1, and other related IgV family members.

[0113] Homologues of human TREM1 include, but are not limited to, the natural killer (NK) cell receptor NK-p44 (NCTR2), polymeric immunoglobulin receptor (pIgR), CD300E, CD300A, CD300C, and TREML1 / TLT1. In some embodiments, NCTR2 shares similarity with TREM1 within the IgV domain.

[0114] DAP12 protein In one aspect, the present disclosure provides anti-TREM1 antibodies that can further modulate one or more DAP12 activities of a DAP12 protein expressed in a cell. In several signaling pathways, an aspartic acid residue in DAP12 interacts with the transmembrane domain of human TREM1, which contains a lysine at amino acid residue 217, to transduce signaling from TREM2, TREM1, and other related IgV family member proteins.

[0115] DAP12 is variously referred to as killer-activating receptor-associated protein, KAR-associated protein (KARAP), PLOSL, PLO-SL, TYRO protein, and tyrosine kinase-associated protein. DAP12 is a single-pass type I membrane-spanning protein. It can associate with the killer cell inhibitory receptor (KIR) family of membrane glycoproteins and act as an activating signal transduction element. In other embodiments, DAP12 protein binds to zeta chain (TCR)-associated protein kinase 70 kDa (ZAP-70) and spleen tyrosine kinase (SYK), and may play a role in signal transduction, bone modeling, brain myelination, and inflammation.

[0116] Human DAP12 is 113 amino acids long. It is a homodimeric, disulfide-bonded protein. DAP12 contains an extracellular domain located at amino acid residues 22-40 in humans, a transmembrane domain located at amino acid residues 41-61 in human DAP12, and an intracellular domain located at amino acid residues 62-113 in human DAP12. The immunoreceptor tyrosine-based activation motif (ITAM) domain is located at amino acid residues 80-113 in human DAP12.

[0117] An example of a human DAP12 amino acid sequence is shown below as SEQ ID NO:560: MGGLEPCSRL LLLPLLLAVS GLRPVQAQAQ SDCSCSTVSP GVLAGIVMGD LVLTVLIALA VYFLGRLVPR GRGAAEAATR KQRITETESP YQELQGQRSD VYSDLNTQRP YYK

[0118] An exemplary human DAP12 may be a precursor protein that includes a signal peptide. In some embodiments, the human DAP12 is a mature protein that does not include a signal peptide. In some embodiments, the mature DAP12 protein is expressed on a cell.

[0119] Mutations in the gene encoding DAP12 have been associated with polycystic lipomembranous bone dysplasia with sclerosing leukoencephalopathy (PLOSL), also known as Nasu-Hakola disease.

[0120] Multiple alternative transcript variants encoding individual isoforms of DAP12 have been identified. DAP12 non-covalently associates with activating receptors of the CD300 family. Cross-linking of the CD300-TYROBP / DAP12 complex results in cell activation, such as integrin-mediated neutrophil activation. In some embodiments, DAP12 interacts with SIRPB1, TREM2, CLECSF5, SIGLEC14, CD300LB, CD300E, and CD300D by homology and via ITAM domains, and with SYK via SH2 domains. In other embodiments, DAP12 activates SYK, which mediates integrin-mediated activation of neutrophils and macrophages. In other embodiments, DAP12 interacts with KLRC2 and KIR2DS3.

[0121] DAP12 proteins include, but are not limited to, mammalian DAP12 proteins, human DAP12 proteins (Uniprot accession number O43914), mouse DAP12 proteins (Uniprot accession number O54885), rat DAP12 proteins (Uniprot accession number Q6X9T7), rhesus monkey DAP12 proteins (Uniprot accession number Q8WNQ8), bovine DAP12 proteins (Uniprot accession number Q95J80), and porcine DAP12 proteins (Uniprot accession number Q9TU45). As used herein, "DAP12 proteins" refers to both wild-type and naturally occurring mutant sequences.

[0122] Anti-TREM1 antibody Certain aspects of the present disclosure relate to antibodies that specifically bind to TREM1. In some embodiments, the antibodies of the present disclosure bind to mature TREM1 protein. In some embodiments, the antibodies of the present disclosure bind to mature TREM1 protein expressed on cells. In some embodiments, the antibodies of the present disclosure bind to TREM1 protein expressed on one or more human cells selected from human dendritic cells, human macrophages, human monocytes, human neutrophils, human osteoclasts, human dermal Langerhans cells, human Kupffer cells, human microglia, and any combination thereof. In some embodiments, the antibodies of the present disclosure are agonistic antibodies. In some embodiments, the antibodies of the present disclosure are inactive antibodies. In some embodiments, the antibodies of the present disclosure are antagonistic antibodies.

[0123] In some embodiments, the anti-TREM1 antibodies of the present disclosure bind to a TREM1 protein without competing, inhibiting, or otherwise blocking the binding of one or more TREM1 ligands to the TREM1 protein. Examples of suitable TREM1 ligands include, but are not limited to, a TREM1 ligand expressed by Escherichia coli cells, apoptotic cells, nucleic acids, anionic lipids, anionic APOE2, anionic APOE3, anionic APOE4, lipidated APOE2, lipidated APOE3, lipidated APOE4, zwitterionic lipids, negatively charged phospholipids, phosphatidylserine, sulfatides, phosphatidylcholine, sphingomyelin, membrane phospholipids, lipidated proteins, proteolipids, lipidated peptides, and lipidated amyloid beta peptide. Thus, in certain embodiments, the one or more TREM1 ligands include E. coli cells, apoptotic cells, nucleic acids, anionic lipids, zwitterionic lipids, negatively charged phospholipids, phosphatidylserine (PS), sulfatides, phosphatidylcholine, sphingomyelin (SM), phospholipids, lipidated proteins, proteolipids, lipidated peptides, and lipidated amyloid beta peptide.

[0124] Agonist anti-TREM1 antibodies One class of anti-TREM1 antibodies of the present invention are agonist antibodies. For example, because the TREM1 receptor is believed to require cell surface clustering to transmit signals, agonist antibodies may have the unique feature of stimulating the TREM1 receptor. For example, agonist anti-TREM1 antibodies may have appropriate epitope specificity compatible with receptor activation and the ability to induce or maintain receptor clustering on the cell surface. Furthermore, agonist anti-TREM1 antibodies of the present disclosure may exhibit the ability to bind to TREM1 without blocking the simultaneous binding of one or more TREM1 ligands. The anti-TREM1 antibodies disclosed herein may further exhibit additive and / or synergistic functional interactions with one or more TREM1 ligands. Thus, in some embodiments, the maximal activity of TREM1, when bound to an anti-TREM1 antibody of the present disclosure in combination with one or more TREM1 ligands of the present disclosure, may be greater (e.g., enhanced) than the maximal activity of TREM1 when exposed to a saturating concentration of the ligand alone or a saturating concentration of the antibody alone. Furthermore, in the presence of the antibody, the activity of TREM1 at a given concentration of TREM1 ligand may be greater (e.g., enhanced). Thus, in some embodiments, the anti-TREM1 antibodies of the present disclosure have an additive effect with one or more TREM1 ligands, enhancing one or more TREM1 activities when bound to the TREM1 protein. In some embodiments, the anti-TREM1 antibodies of the present disclosure cooperate with one or more TREM1 ligands to enhance one or more TREM1 activities. In some embodiments, the anti-TREM1 antibodies of the present disclosure increase the efficacy of one or more TREM1 ligands to induce one or more TREM1 activities compared to the efficacy of the one or more TREM1 ligands to induce one or more TREM1 activities in the absence of the antibody. In some embodiments, the anti-TREM1 antibodies of the present disclosure enhance one or more TREM1 activities in the absence of cell surface clustering of TREM1. In some embodiments, the anti-TREM1 antibodies of the present disclosure enhance one or more TREM1 activities by inducing or maintaining cell surface clustering of TREM1.In some embodiments, the anti-TREM1 antibodies of the present disclosure are clustered by one or more Fc-γ receptors expressed on one or more immune cells, including, but not limited to, B cells and microglial cells. In some embodiments, the enhancement of one or more TREM1 activities induced by binding of one or more TREM1 ligands to the TREM1 protein is measured in primary cells, including, but not limited to, dendritic cells, bone marrow-derived dendritic cells, monocytes, microglia, macrophages, neutrophils, NK cells, osteoclasts, dermal Langerhans cells, and Kupffer cells, or in cell lines, and the enhancement of one or more TREM1 activities induced by binding of one or more TREM1 ligands to the TREM1 protein is measured, for example, using an in vitro cell assay.

[0125] In vivo, anti-TREM1 antibodies of the present disclosure can activate receptors by several possible mechanisms. In some embodiments, agonistic anti-TREM1 antibodies of the present disclosure have the ability to activate TREM1 in solution without the need for clustering with a plate-bound secondary antibody or clustering by an Fcγ receptor due to appropriate epitope specificity. In some embodiments, anti-TREM1 antibodies of the present disclosure have a human antibody isotype, such as IgG2, which, due to its unique structure, has the intrinsic ability to cluster receptors or hold receptors in a clustered configuration, thereby activating receptors such as TREM1 without binding to an Fc receptor (see, e.g., White et al. (2015) Cancer Cell 27, 138-148).

[0126] In some embodiments, the anti-TREM1 antibodies of the present disclosure cluster receptors (e.g., TREM1) by binding to Fcγ receptors on neighboring cells. Binding of the constant IgG Fc portion of an antibody to an Fcγ receptor leads to aggregation of the antibody, which in turn aggregates the receptors to which they bind via their variable regions (Chu et al. (2008) Mol Immunol 45:3926-3933; and Wilson et al. (2011) Cancer Cell 19:101-113). Binding to the inhibitory Fcγ receptor FcγR (FcγRIIB), which does not induce cytokine secretion, oxidative burst, increased phagocytosis, and enhanced antibody-dependent cell-mediated cytotoxicity (ADCC), is often the preferred method of clustering antibodies in vivo because binding to FcγRIIB is not associated with adverse immune effects.

[0127] Other mechanisms can also be used to cluster receptors, including the TREM1 receptor. For example, in some embodiments, antibody fragments (e.g., Fab fragments) cross-linked together can be used to cluster receptors (e.g., TREM1) in a manner similar to antibodies with Fc regions that bind to Fcγ receptors, as described above. In some embodiments, cross-linked antibody fragments (e.g., Fab fragments) can function as agonist antibodies when they induce receptor clustering at the cell surface and bind to the appropriate epitope on a target, such as TREM1.

[0128] In some embodiments, antibodies of the present disclosure that bind to the TREM1 protein may include agonist antibodies that, due to their epitope specificity, bind to TREM1 and activate one or more TREM1 activities. In some embodiments, such antibodies may bind to a ligand-binding site on TREM1 and mimic the action of one or more TREM1 ligands, or may stimulate a target antigen to transduce a signal by binding to one or more domains that are not the ligand-binding site. In some embodiments, the antibody does not compete with or otherwise block ligand binding to TREM1. In some embodiments, the antibody acts additively or synergistically with one or more TREM1 ligands to activate and / or enhance one or more TREM1 activities.

[0129] As used herein, an agonist anti-TREM1 antibody of the present disclosure enhances one or more TREM1 activities induced by the binding of one or more TREM1 ligands to a TREM1 protein if it induces at least a 2-fold, at least a 3-fold, at least a 4-fold, at least a 5-fold, at least a 6-fold, at least a 7-fold, at least a 8-fold, at least a 9-fold, at least a 10-fold, at least a 11-fold, at least a 12-fold, at least a 13-fold, at least a 14-fold, at least a 15-fold, at least a 16-fold, at least a 17-fold, at least a 18-fold, at least a 19-fold, at least a 20-fold or more increase in one or more TREM1 activities compared to the level of one or more TREM1 activities induced by the binding of one or more TREM1 ligands to a TREM1 protein in the absence of the anti-TREM1 antibody. In some embodiments, an increase in one or more TREM1 activities is measured by any suitable in vitro cell-based assay or suitable in vivo model, e.g., see the Examples section or known in the art, for example, by utilizing a luciferase-based reporter assay that measures TREM1-dependent gene expression, by using Western blot analysis that measures increased TREM1-induced phosphorylation of downstream signaling partners such as Syk, or by utilizing flow cytometry such as fluorescence-activated cell sorting (FACS) that measures changes in cell surface levels of markers of TREM1 activation. Any in vitro cell-based assay or suitable in vivo model described herein or known in the art can be used to measure the interaction (e.g., binding) between TREM1 and one or more TREM1 ligands.

[0130] As used herein, an anti-TREM1 antibody of the disclosure is considered not to compete with, inhibit, or otherwise block the interaction (e.g., binding) between one or more TREM1 ligands and TREM1 if it reduces ligand binding to TREM1 by less than 20% at saturating antibody concentrations using any in vitro or cell-based culture assay described herein or known in the art. In some embodiments, an anti-TREM1 antibody of the disclosure inhibits the interaction (e.g., binding) between one or more TREM1 ligands and TREM1 by less than 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, or 1% at saturating antibody concentrations using any in vitro or cell-based culture assay described herein or known in the art.

[0131] In some embodiments, the agonist anti-TREM1 antibodies of the present disclosure induce one or more activities of TREM1 after binding to a TREM1 protein expressed on a cell. In some embodiments, the antibodies induce one or more activities of TREM1 after binding to a soluble TREM1 protein that is not bound to a cell membrane. In certain embodiments, the soluble TREM1 protein (sTREM1) is non-cellular. In certain embodiments, the soluble TREM1 protein (sTREM1) can be found in, but not limited to, the extracellular environment, blood serum, cerebrospinal fluid (CSF), and the interstitial space within tissues. In some embodiments, the anti-TREM1 antibodies of the present disclosure increase the level of soluble TREM1 protein (sTREM1) and / or increase the half-life of the soluble TREM1 (sTREM1) protein.

[0132] TREM1 activities induced or enhanced by an anti-TREM1 agonist antibody of the present disclosure and / or one or more TREM1 ligands of the present disclosure include, but are not limited to, TREM1 binding to DAP12; TREM1 phosphorylation and / or DAP12 phosphorylation; activation of one or more tyrosine kinases, for example, SRC tyrosine kinases such as Syk kinase or ZAP70 kinase, or both; activation of phosphatidylinositol 3-kinase (PI3K); activation of protein kinase B (Akt); recruitment of phospholipase C-γ (PLC-γ) to the cell plasma membrane, activation of PLC-γ, or both; recruitment of the TEC-family kinase dVav to the cell plasma membrane; inhibition of MAPK signaling; phosphorylation of linker for activation of T cells (LAT), linker for activation of B cells (LAB), or both; or activation of IL-2-induced tyrosine kinase (Itk). Further TREM1 activities induced or enhanced by anti-TREM1 agonist antibodies include: (a) modulating the expression and / or activity of one or more anti-inflammatory cytokines, optionally wherein the one or more anti-inflammatory cytokines are selected from IL-4, IL-10 TGF-β, IL-13, IL-35 IL-16, IFN-α, IL-1Rα, VEGF, G-CSF, and soluble receptors for TNF or IL-6; (b) modulating the expression and / or activity of one or more anti-inflammatory cytokines in one or more cells selected from macrophages, e.g., M1 macrophages, activated M1 macrophages and / or M2 macrophages, dendritic cells, bone marrow-derived dendritic cells, monocytes, osteoclasts, dermal Langerhans cells, Kupffer cells, and microglial cells; (c) modulating the expression and / or activity of one or more inflammatory cytokines, optionally wherein the one or more inflammatory cytokines are selected from IFN-β, IL-1α, IL-1β, TNF-α, IL-6, IL-8, CRP, IL-20 family members, IL-33, LIF, IFN-γ, OSM, CNTF, GM-CSF, IL-11, IL-12, IL-17, IL-18, IL-23, CXCL10, and MCP-1; (d) macrophages;(e) activating extracellular signal-regulated kinase (ERK) phosphorylation; (f) activating tyrosine phosphorylation in multiple cellular proteins; (g) regulating the expression and / or activity of one or more inflammatory cytokines in one or more cells selected from M1 macrophages, activated M1 macrophages, M2 macrophages, dendritic cells, bone marrow-derived dendritic cells, monocytes, osteoclasts, dermal Langerhans cells, Kupffer cells, and microglial cells; (g) activating the expression of CC chemokine receptor 7 (CCR7); (h) activating the expression of CCL19 and CCL2 (i) activating microglial cell chemotaxis towards CD4+ T cells expressing CD4+ T cells, CD8+ T cells, and / or regulatory T cells by one or more cells selected from dendritic cells, bone marrow-derived dendritic cells, monocytes, microglia, M1 microglia, activated M1 microglia, M2 microglia, macrophages, M1 macrophages, activated M1 macrophages, and M2 macrophages; (j) activating osteoclast production, increasing the rate of osteoclast formation, or both; (k) enhancing the induction and / or regulatory function of one or more T cells, such as CD8+ T cells, CD4+ T cells, and / or regulatory T cells, by one or more cells selected from dendritic cells, bone marrow-derived dendritic cells, monocytes, microglia, M1 microglia, activated M1 microglia, M2 microglia, macrophages, M1 macrophages, activated M1 macrophages, and M2 macrophages; (j) activating osteoclast production, increasing the rate of osteoclast formation, or both; (l) increasing the survival of one or more cells selected from dendritic cells, bone marrow-derived dendritic cells, macrophages, M1 macrophages, activated M1 macrophages, M2 macrophages, monocytes, osteoclasts, T cells, T helper cells, cytotoxic T cells, granulocytes, neutrophils, microglia, M1 microglia, activated M1 microglia, and M2 microglia; (m) increasing the proliferation of one or more cells selected from dendritic cells, bone marrow-derived dendritic cells, macrophages, M1 macrophages, activated M1 macrophages, M2 macrophages, monocytes, osteoclasts, T cells, T helper cells, cytotoxic T cells, granulocytes, neutrophils, microglia, M1 microglia, activated M1 microglia, and M2 microglia; (n) activating the migration of one or more cells selected from dendritic cells, bone marrow-derived dendritic cells, macrophages,(o) activating one or more functions of one or more cells selected from M1 macrophages, activated M1 macrophages, M2 macrophages, monocytes, osteoclasts, T cells, T helper cells, cytotoxic T cells, granulocytes, neutrophils, microglia, M1 microglia, activated M1 microglia, and M2 microglia; (o) activating one or more functions of one or more cells selected from dendritic cells, bone marrow-derived dendritic cells, macrophages, M1 macrophages, activated M1 macrophages, M2 macrophages, monocytes, osteoclasts, T cells, T helper cells, cytotoxic T cells, granulocytes, neutrophils, microglia, M1 microglia, activated M1 microglia, and M2 microglia; (p) activating one or more types of clearance selected from apoptotic neuron clearance, neural tissue debris clearance, non-neural tissue debris clearance, bacterial clearance, other foreign body clearance, disease-causing protein clearance, disease-causing peptide clearance, and tumor cell clearance, optionally wherein the disease-causing protein is amyloid beta, oligomeric amyloid beta, amyloid beta plaque, amyloid precursor protein or fragments thereof, tau, IAPP, alpha-synuclein, TDP-43, FUS protein, C9orf72 (chromosome 9 open reading frame 72), c9RAN protein, prion protein, PrPSc, huntingtin, calcitonin, superoxide dismutase, ataxin, ataxin 1, ataxin B, amyloid precursor protein ... B, ataxin C, ataxin D, ataxin E, ataxin I, ataxin I, ataxin I, ataxin I, ataxin I, ataxin I, ataxin I, ataxin I, ataxin I, ataxin I, ataxin I, ataxin I, ataxin I, ataxin I, ataxin I, ataxin I, ataxin I, ataxin I, ataxin I, ataxin I, ataxin I, ataxin I, ataxin I, ataxin I, ataxin I, 2, ataxin 3, ataxin 7, ataxin 8, ataxin 10, Lewy bodies, atrial natriuretic factor, islet amyloid polypeptide, insulin, apolipoprotein AI, serum amyloid A, medin, prolactin, transthyretin, lysozyme, β2-microglobulin, gelsolin, keratoepithelin, cystatin, immunoglobulin light chain AL, S-IBM protein, repeat-associated non-ATG (RAN) translation products, dipeptide repeat (DPR) peptides, glycine-alanine (GA) repeat peptides, glycine-proline (GP) repeat peptides, glycine-arginine (GR) repeat peptides, proline-alanine (PA) repeat peptides,(q) activating one or more types of clearance of apoptotic neurons, neural and non-neural tissue debris, bacteria, other foreign bodies, disease-causing proteins, disease-causing peptides, disease-causing nucleic acids, or tumor cells, wherein optionally the disease-causing nucleic acids are selected from antisense oligonucleotides, ... GGCCCC (G2C4) repeat-expanded RNA, and the disease-causing proteins are amyloid beta, oligomeric amyloid beta, amyloid beta plaques, amyloid precursor protein or fragments thereof, tau, IAPP, α-synuclein, TDP-43, FUS protein, C9orf72 (chromosome 9 open reading frame 72), c9RAN protein, prion protein, PrPSc, huntingtin, calcitonin, superoxide dismutase, ataxin, ataxin 1, ataxin 2, ataxin 3, ataxin 7, ataxin 8, ataxin 10, Lewy bodies, atrial natriuretic factor, islet amyloid polypeptide, insulin, apolipoprotein AI, serum amyloid A, medin, prolactin, the tumor cell is selected from bladder cancer, brain cancer, glioma or glioblastoma such as low-grade glioma, breast cancer, cervical cancer, colon cancer, rectal cancer, endometrial cancer, kidney cancer, renal cell carcinoma, renal pelvis cancer, leukemia, lung cancer,For example, inhibiting phagocytosis from a cancer selected from non-small cell lung cancer, melanoma, non-Hodgkin's lymphoma, pancreatic cancer, prostate cancer, ovarian cancer, fibrosarcoma, or thyroid cancer; (r) binding to a TREM1 ligand on tumor cells; (s) binding to a TREM1 ligand on cells selected from neutrophils, dendritic cells, bone marrow-derived dendritic cells, monocytes, microglia, and macrophages; (t) binding to a TREM1 ligand on cells selected from microglia, macrophages, dendritic cells, bone marrow-derived dendritic cells, neutrophils, (u) activating the anti-tumor cell proliferation activity of one or more of microglia, macrophages, dendritic cells, bone marrow-derived dendritic cells, neutrophils, T cells, T helper cells, or cytotoxic T cells; (v) activating the anti-tumor cell metastasis activity of one or more of microglia, macrophages, dendritic cells, bone marrow-derived dendritic cells, neutrophils, T cells, T helper cells, or cytotoxic T cells; (w) activating one or more ITAM motif-containing receptors. (x) activating signaling by one or more pattern recognition receptors (PRRs), optionally wherein the one or more PRRs are selected from receptors that identify pathogen-associated molecular patterns (PAMPs), receptors that identify damage-associated molecular patterns (DAMPs), and any combination thereof; (y) activating one or more ITAM motif-containing receptors, optionally wherein the one or more ITAM motif-containing receptors are selected from TREM1, TREM1, FcγR, DAP10, and DAP12; ... 0-2 YxxL / IX 6-8(z) activating signaling by one or more Toll-like receptors; (aa) activating the JAK-STAT signaling pathway; (bb) activating nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB); (cc) phosphorylating ITAM motif-containing receptors; (dd) modulating expression of one or more inflammatory receptors, optionally wherein the one or more inflammatory receptors comprise CD86, and the one or more inflammatory receptors are expressed by microglia, macrophages, dendritic cells, bone marrow, or the like. (ee) increasing expression of one or more TREM1-dependent genes; (gg) normalizing perturbed TREM1-dependent gene expression; (ff) increasing expression of one or more ITAM-dependent genes, optionally wherein the one or more ITAM-dependent genes are activated by nuclear factor of activated T cells (NFAT) transcription factor; (gg) increasing expression of immune suppressor dendritic cells, immune suppressor macrophages ... (hh) inhibiting the differentiation of one or more of immune suppressor dendritic cells, immune suppressor macrophages, myeloid-derived suppressor cells, tumor-associated macrophages, immune suppressor neutrophils, and regulatory T cells; (ii) inhibiting the functionality of one or more of immune suppressor dendritic cells, immune suppressor macrophages, myeloid-derived suppressor cells, tumor-associated macrophages, immune suppressor neutrophils, and regulatory T cells; (jj) reducing the number of tumor-promoting myeloid / granulocytic immunosuppressive cells in tumors, peripheral blood or other lymphoid organs; (kk) inhibiting the tumor-promoting activity of myeloid-derived suppressor cells; (ll) reducing the expression of tumor-promoting cytokines in tumors or in peripheral blood, optionally wherein the tumor-promoting cytokine is TGF-beta or IL-10; (mm) reducing the tumor infiltration of tumor-promoting FoxP3+ regulatory T lymphocytes;(nn) increasing activation of tumor-specific T lymphocytes with tumor-killing capacity, (oo) decreasing tumor burden, (pp) decreasing tumor growth rate, (qq) increasing the effectiveness of one or more immunotherapies that modulate anti-tumor T cell responses, optionally wherein the one or more immunotherapies are selected from PD1 / PDL1 blockade, CTLA-4 blockade, and cancer vaccines, (rr) inhibiting PLCγ / PKC / calcium mobilization, (uu) inhibiting PI3K / Akt, Ras / MAPK signaling, (ss) increasing phagocytosis by dendritic cells, macrophages, monocytes, and / or microglia, (tt) inducing or maintaining TREM1 clustering on the cell surface, (yy) increasing memory, and (zz) reducing cognitive deficits.

[0133] In some embodiments, antibody cross-linking is necessary for agonist antibody function. Antibody cross-linking can occur in vitro by binding with a secondary antibody or in vivo by binding to an Fc receptor. For example, an antagonist antibody can be converted to an agonist antibody in vitro by biotin / streptavidin cross-linking or secondary antibody binding (see, e.g., Gravestein et al. (1996) J. Exp. Med. 184:675-685; Gravestein et al. (1994) International Immunol. 7:551-557). Agonist antibodies can exert their activity by mimicking the biological activity of receptor ligands or by enhancing receptor aggregation, thereby activating receptor signaling.

[0134] Antibodies that depend on binding to FcγR receptors to activate targeted receptors can lose their activity if genetically engineered to eliminate FcγR binding (see, e.g., Wilson et al., (2011) Cancer Cell 19, 101-113; Armour et al., (2003) Immunology 40 (2003) 585-593; and White et al., (2015) Cancer Cell 27, 138-148). Thus, it is believed that the anti-TREM1 antibodies of the present disclosure with appropriate epitope specificity are agonistic antibodies and can activate target antigens with minimal adverse effects if the antibodies have an Fc domain (CH1 and hinge region) from the human IgG2 isotype or another type of Fc domain that can preferentially bind the inhibitory FcγRIIB receptor or a variant thereof.

[0135] Exemplary agonist antibody Fc isotypes and modifications are provided below in Table A. In some embodiments, the agonist antibody has an Fc isotype listed in Table A below. TIFF2024119791000004.tif234170TIFF2024119791000005.tif247170TIFF2024119791000006.tif106170

[0136] Without being bound by theory, it is believed that antibodies having human IgG1 or IgG3 isotypes and mutants thereof that bind to activating Fcγ receptors I, IIA, IIC, IIIA, and IIIB in humans and / or Fcγ receptors I, III, and IV in mice (e.g., Strohl (2009) Current Opinion in Biotechnology 2009, 20:685-691) in addition to the isotypes listed in Table A may also act as agonist antibodies in vivo but may be associated with adverse effects related to ADCC. However, such Fcγ receptors appear to be less available for antibody binding in vivo compared to the inhibitory Fcγ receptor FcγRIIB (see, e.g., White et al. (2013) Cancer Immunol. Immunother. 62, 941-948; and Li et al. (2011) Science 333(6045):1030-1034).

[0137] In some embodiments, the agonist antibody is of the IgG class, IgM class, or IgA class. In some embodiments, the agonist antibody has an IgG1, IgG2, IgG3, or IgG4 isotype.

[0138] In certain embodiments, the agonist antibody has an IgG2 isotype. In some embodiments, the agonist antibody comprises a human IgG2 constant region. In some embodiments, the human IgG2 constant region comprises an Fc region. In some embodiments, the agonist antibody induces one or more TREM1 activities, DAP12 activities, or both, independently of binding to an Fc receptor. In some embodiments, the agonist antibody binds to an inhibitory Fc receptor. In certain embodiments, the inhibitory Fc receptor is inhibitory Fc-gamma receptor IIB (FcγIIB). In some embodiments, the Fc region contains one or more modifications. For example, in some embodiments, the Fc region contains one or more amino acid substitutions (e.g., relative to a wild-type Fc region of the same isotype). In some embodiments, the one or more amino acid substitutions are selected from the group consisting of V234A (Alegre et al., (1994) Transplantation 57:1537-1543.31; Xu et al., (2000) Cell Immunol, 200:16-26), G237A (Cole et al., (1999) Transplantation, 68:563-571), H268Q, V309L, A330S, P331S (US2007 / 0148167; Armour et al., (1999) Eur J Immunol 29:2613-2624; Armour et al., (2000) The Haematology Journal 1(Suppl. 1):27; Armour et al., (2000) The Haematology Journal 1(Suppl. 1):27), C232S and / or C233S (White et al. (2015) Cancer Cell 27, 138-148), S267E, L328F (Chu et al. (2008) Mol Immunol, 45:3926-3933), M252Y, S254T and / or T256E, where the amino acid positions are according to the EU or Kabat numbering convention.

[0139] In some embodiments, the agonist antibody has an IgG2 isotype with a heavy chain constant domain containing a C127S amino acid substitution, where amino acid positions follow the EU or Kabat numbering convention (White et al., (2015) Cancer Cell 27, 138-148; Lightle et al., (2010) PROTEIN SCIENCE 19:753-762; and WO 2008079246).

[0140] In some embodiments, the agonist antibody has an IgG2 isotype with a kappa light chain constant domain containing a C214S amino acid substitution, where amino acid positions follow the EU or Kabat numbering convention (White et al., (2015) Cancer Cell 27, 138-148; Lightle et al., (2010) PROTEIN SCIENCE 19:753-762; and WO 2008079246).

[0141] In certain embodiments, the agonist antibody has an IgG1 isotype. In some embodiments, the agonist antibody comprises a mouse IgG1 constant region. In some embodiments, the agonist antibody comprises a human IgG1 constant region. In some embodiments, the human IgG1 constant region comprises an Fc region. In some embodiments, the agonist antibody binds to an inhibitory Fc receptor. In certain embodiments, the inhibitory Fc receptor is inhibitory Fc-gamma receptor IIB (FcγIIB). In some embodiments, the Fc region contains one or more modifications. For example, in some embodiments, the Fc region contains one or more amino acid substitutions (e.g., relative to a wild-type Fc region of the same isotype). In some embodiments, the one or more amino acid substitutions are selected from the group consisting of N297A (Bolt S et al. (1993) Eur J Immunol 23:403-411), D265A (Shields et al. (2001) RJ Biol. Chem. 276, 6591-6604), L234A, L235A (Hutchins et al. (1995) Proc Natl Acad Sci USA 92:11980-11984; Alegre et al. (1994) Transplantation 57:1537-1543. 31; Xu et al. (2000) Cell Immunol 200:16-26), G237A (Alegre et al. (1994) Transplantation 57:1537-1543. 31; Xu et al. (2000) Cell Immunol 200:16-26), and / or G237A (Alegre et al. (1994) Transplantation 57:1537-1543. 31; Xu et al. (2000) Cell Immunol 200:16-26). Immunol, 200:16-26), C226S, C229S, E233P, L234V, L234F, L235E (McEarchern et al., (2007) Blood, 109:1185-1192), P331S (Sazinsky et al., (2008) Proc Natl Acad Sci USA 2008, 105:20167-20172), S267E, L328F, A330L, M252Y, S254T and / or T256E, wherein the amino acid positions are according to the EU or Kabat numbering convention.

[0142] In some embodiments, the antibody comprises an IgG2 isotype heavy chain constant domain 1 (CH1) and hinge region (White et al., (2015) Cancer Cell 27, 138-148). In particular embodiments, the IgG2 isotype CH1 and hinge region comprises the amino acid sequence ASTKGPSVFPLAPCSRSTSESTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSNFGTQTYTCNVDHKPSNTKVDKTVERKCCVECPPCP (SEQ ID NO: 476). In some embodiments, the antibody Fc region contains an S267E amino acid substitution, an L328F amino acid substitution, or both, and / or an N297A or N297Q amino acid substitution, where amino acid positions are according to EU or Kabat numbering conventions.

[0143] In certain embodiments, the agonist antibody has an IgG4 isotype. In some embodiments, the agonist antibody comprises a human IgG4 constant region. In some embodiments, the human IgG4 constant region comprises an Fc region. In some embodiments, the agonist antibody binds to an inhibitory Fc receptor. In certain embodiments, the inhibitory Fc receptor is inhibitory Fc-gamma receptor IIB (FcγIIB). In some embodiments, the Fc region contains one or more modifications. For example, in some embodiments, the Fc region contains one or more amino acid substitutions (e.g., relative to a wild-type Fc region of the same isotype). In some embodiments, the one or more amino acid substitutions are selected from L235A, G237A, S228P, L236E (Reddy et al. (2000) J Immunol, 164:1925-1933), S267E, E318A, L328F, M252Y, S254T and / or T256E, where the amino acid positions are according to the EU or Kabat numbering convention.

[0144] In certain embodiments, the agonist antibody has a hybrid IgG2 / 4 isotype. In some embodiments, the agonist antibody comprises an amino acid sequence containing amino acids 118-260 according to EU or Kabat numbering of human IgG2 and amino acids 261-447 according to EU or Kabat numbering of human IgG4 (WO 1997 / 11971, WO 2007 / 106585).

[0145] In certain embodiments, the antibody comprises a murine IgG4 constant region (Bartholomaeus et al. (2014) J. Immunol. 192, 2091-2098).

[0146] In some embodiments, the Fc region further contains one or more additional amino acid substitutions selected from A330L, L234F, L235E, or P331S according to EU or Kabat numbering, and any combination thereof.

[0147] inert antibody Another class of antibodies of the present disclosure includes inactive antibodies. As used herein, an "inactive" antibody refers to an antibody that specifically binds to a target antigen but does not modulate (e.g., reduce / inhibit or activate / induce) antigen function. For example, in the case of TREM1, an inactive antibody does not modulate ligand binding and / or TREM1 activity. Without being bound by theory, it is believed that an antibody that does not have the ability to cluster TREM1 on the cell surface may be an inactive antibody, even if it has an epitope specificity compatible with receptor activation.

[0148] In some embodiments, antibodies that bind to the TREM1 protein can include antibodies that bind to TREM1 but, due to their epitope specificity, do not modulate protein function. Such functionally inactive antibodies can be used to deliver toxins or as cargo to tumor cells, as described for the CD33 antibody gemtuzumab ozogamicin (commercially available as Mylotarg), which has been conjugated to cytotoxic agents from the calicheamicin class and used to target and kill acute myeloid leukemia tumors (Naito et al. (2000) Leukemia 14:1436-1443; Ricart (2011) Clin Cancer Res 17:6417-6436; Hamann et al. (2002) Journal: Bioconjugate Chemistry 13:47-58; and Beitz et al. (2001) Clin Cancer Res 7:1490-6). Thus, in some embodiments, the antibodies of the present disclosure are inactive antibodies that bind to TREM1 but are unable to induce one or more TREM1 activities (eg, the TREM1 activities described herein).

[0149] Exemplary inactivating antibody Fc isotypes and modifications are provided below in Table B. In some embodiments, the inactivating antibody has an Fc isotype listed in Table B below.

[0150] Antagonist anti-TREM1 antibodies Another class of antibodies is antagonist antibodies. In some embodiments, antibodies that bind to a TREM1 protein may include antagonist antibodies that bind to TREM1 and inhibit one or more TREM1 activities by either preventing the interaction between TREM1 and one or more TREM1 ligands, or by preventing the transmission of a signal from the extracellular domain of TREM1 to the cytoplasm of the cell in the presence of a ligand.

[0151] The TREM1 receptor is believed to require clustering on the cell surface to transmit signals. Thus, in some embodiments, an antagonistic antibody may have the unique feature of inhibiting TREM1 receptor clustering on the cell surface. For example, such an antibody may have the appropriate epitope specificity compatible with receptor inhibition and the ability to block or reverse receptor clustering on the cell surface. In some embodiments, an antagonistic antibody of the present disclosure may have the epitope specificity of an agonistic antibody of the present disclosure, but has an Fc domain that is not capable of binding to Fcγ receptors and therefore cannot cluster the TREM1 receptor.

[0152] In some embodiments, the antagonist antibody reduces the activity of one or more TREM1-dependent genes. In some embodiments, the anti-TREM1 antibody reduces the level of TREM1 in one or more cells (e.g., cell surface, intracellular, or total levels). In some embodiments, the anti-TREM1 antibody induces degradation of TREM1. In some embodiments, the anti-TREM1 antibody induces cleavage of TREM1. In some embodiments, the anti-TREM1 antibody induces internalization of TREM1. In some embodiments, the anti-TREM1 antibody induces shedding of TREM1. In some embodiments, the anti-TREM1 antibody induces downregulation of TREM1 expression. In some embodiments, the anti-TREM1 antibody inhibits the interaction (e.g., binding) between TREM1 and one or more TREM1 ligands. In some embodiments, the anti-TREM1 antibody transiently activates and then induces degradation of TREM1. In some embodiments, the anti-TREM1 antibody is transiently activated and then induces cleavage of TREM1. In some embodiments, the anti-TREM1 antibody is transiently activated and then induces internalization of TREM1. In some embodiments, the anti-TREM1 antibody is transiently activated and then induces shedding of TREM1. In some embodiments, the anti-TREM1 antibody is transiently activated and then induces downregulation of TREM1 expression. In some embodiments, the anti-TREM1 antibody is transiently activated and then induces a decrease in TREM1 expression. In certain embodiments, the individual has a TREM1 mutant allele. In some embodiments, the anti-TREM1 antibody acts in solution.

[0153] In some examples, antagonist-TREM1 antibodies of the present disclosure may bind to TREM1 and block the binding of one or more TREM1 ligands. Anti-TREM1 antibodies of the present disclosure may further exhibit inhibitory interactions with one or more TREM1 ligands. Thus, in some embodiments, the maximal activity of TREM1, when bound to an anti-TREM1 antibody as described herein in combination with one or more TREM1 ligands of the present disclosure, may be less (e.g., reduced) than the maximal activity of TREM1 when exposed to a saturating concentration of the ligand. Furthermore, the activity of TREM1 at a given concentration of TREM1 ligand may be less (e.g., reduced) in the presence of the antibody. Thus, in some embodiments, anti-TREM1 antibodies of the present disclosure have a disrupting effect that inhibits one or more TREM1 activities when bound to a TREM1 protein with one or more TREM1 ligands. In some embodiments, the anti-TREM1 antibodies of the present disclosure reduce the ability of one or more TREM1 ligands to induce one or more TREM1 activities compared to the ability of the one or more TREM1 ligands to induce one or more TREM1 activities in the absence of the antibody. In some embodiments, the anti-TREM1 antibodies of the present disclosure inhibit one or more TREM1 activities in the presence of cell surface clustering of TREM1. In some embodiments, the anti-TREM1 antibodies of the present disclosure inhibit one or more TREM1 activities by blocking or reducing cell surface clustering of TREM1. In some embodiments, the anti-TREM1 antibodies of the present disclosure are clustered by one or more Fc-gamma receptors expressed on one or more immune cells, including, but not limited to, B cells and microglial cells.In some embodiments, inhibition of one or more TREM1 activities induced by binding of one or more TREM1 ligands to the TREM1 protein is measured in primary cells, including but not limited to dendritic cells, bone marrow-derived dendritic cells, monocytes, microglia, macrophages, neutrophils, NK cells, osteoclasts, dermal Langerhans cells and Kupffer cells, or in cell lines, and inhibition of one or more TREM1 activities induced by binding of one or more TREM1 ligands to the TREM1 protein is measured, for example, using an in vitro cell assay.

[0154] In some embodiments, the antibody inhibits one or more activities of TREM1 after binding to soluble TREM1 protein that is not bound to a cell membrane. In certain embodiments, soluble TREM1 protein (sTREM1) can be found, without limitation, in the extracellular environment, in blood serum, in cerebrospinal fluid (CSF), and in the interstitial space within tissues. In certain embodiments, the soluble TREM1 protein (sTREM1) is non-cellular. In some embodiments, the anti-TREM1 antibodies of the present disclosure increase the level of soluble TREM1 protein (sTREM1) and / or increase the half-life of soluble TREM1 protein (sTREM1).

[0155] The TREM1 activity inhibited by the anti-TREM1 antibodies of the present disclosure may be (a) modulating the expression of one or more anti-inflammatory cytokines, optionally the one or more anti-inflammatory cytokines being IL-4, IL-10, TGF-β, IL-13, IL-35, or IL-6;(b) modulating the expression of one or more anti-inflammatory cytokines in one or more cells selected from macrophages, dendritic cells, bone marrow-derived dendritic cells, monocytes, osteoclasts, and microglial cells; (c) modulating the expression of one or more pro-inflammatory cytokines, optionally wherein the one or more pro-inflammatory cytokines are IFN-β, IL-1α, IL-1β, TNF-α, IL-1Ra, VEGF, G-CSF, and a soluble receptor for TNF or IL-6; (d) modulating the expression of one or more inflammatory cytokines in one or more cells selected from macrophages, dendritic cells, bone marrow-derived dendritic cells, monocytes, osteoclasts, and microglial cells; (e) activating extracellular signal-regulated kinase (ERK) phosphorylation. (f) activating tyrosine phosphorylation on multiple cellular proteins; (g) regulating the expression of CC chemokine receptor 7 (CCR7); (h) activating microglial cell chemotaxis towards CCL19- and CCL21-expressing cells; (i) activating CD8+ chemotaxis by one or more cells selected from dendritic cells, bone marrow-derived dendritic cells, monocytes, microglia, M1 microglia, activated M1 microglia, M2 microglia, macrophages, M1 macrophages, activated M1 macrophages, and M2 macrophages. (j) increasing the inductive and / or regulatory function of one or more T cells, such as T cells, CD4+ T cells and / or regulatory T cells; (k) activating osteoclast production, increasing the rate of osteoclast formation, or both; (k) increasing the activity of dendritic cells, bone marrow-derived dendritic cells, macrophages, M1 macrophages, activated M1 macrophages, M2 macrophages, monocytes, osteoclasts, T cells, T helper cells, cytotoxic T cells, granulocytes, neutrophils, microglia, M1 microglia, activated M1 microglia, myeloid-derived suppressor cells, Gr-1 + CD11b +(l) increasing the survival of one or more cells selected from myeloid cells and M2 microglia; (l) increasing the survival of one or more cells selected from dendritic cells, bone marrow-derived dendritic cells, macrophages, M1 macrophages, activated M1 macrophages, M2 macrophages, monocytes, osteoclasts, T cells, T helper cells, cytotoxic T cells, granulocytes, neutrophils, myeloid-derived suppressor cells, Gr-1 + CD11b + (m) increasing the proliferation of one or more cells selected from myeloid cells, microglia, M1 microglia, activated M1 microglia, and M2 microglia; (m) activating the migration of one or more cells selected from dendritic cells, bone marrow-derived dendritic cells, macrophages, M1 macrophages, activated M1 macrophages, M2 macrophages, monocytes, osteoclasts, T cells, T helper cells, cytotoxic T cells, granulocytes, neutrophils, microglia, M1 microglia, activated M1 microglia, and M2 microglia; (n) activating the migration of one or more cells selected from dendritic cells, myeloid-derived suppressor cells, Gr-1 + CD11b + (o) activating one or more functions of one or more cells selected from myeloid cells, bone marrow-derived dendritic cells, macrophages, M1 macrophages, activated M1 macrophages, M2 macrophages, monocytes, osteoclasts, T cells, T helper cells, cytotoxic T cells, granulocytes, neutrophils, microglia, M1 microglia, activated M1 microglia, and M2 microglia; (o) activating one or more functions of one or more cells selected from dendritic cells, bone marrow-derived dendritic cells, macrophages, myeloid-derived suppressor cells, Gr-1 + CD11b +(p) activating the maturation of one or more cells selected from myeloid cells, M1 macrophages, activated M1 macrophages, M2 macrophages, monocytes, osteoclasts, T cells, T helper cells, cytotoxic T cells, granulocytes, neutrophils, microglia, M1 microglia, activated M1 microglia, and M2 microglia; (q) binding to a TREM1 ligand on tumor cells; (r) binding to a TREM1 ligand on cells selected from neutrophils, dendritic cells, bone marrow-derived dendritic cells, monocytes, microglia, and macrophages; or activation of a plurality of ITAM motif-containing receptors, optionally wherein one or more ITAM motif-containing receptors are selected from TREM1, TREM1, FcγR, DAP10, and DAP12; (x) activation of signaling by one or more pattern recognition receptors (PRRs), optionally wherein one or more PRRs are selected from receptors that identify pathogen-associated molecular patterns (PAMPs), receptors that identify damage-associated molecular patterns (DAMPs), and any combination thereof; (y) activation of a plurality of ITAM motif-containing receptors, optionally wherein one or more ITAM motif-containing receptors are selected from receptors that identify pathogen-associated molecular patterns (PAMPs), receptors that identify damage-associated molecular patterns (DAMPs), and any combination thereof; 0-2 YxxL / IX 6-8(z) activation of signaling by one or more Toll-like receptors; (aa) activation of the JAK-STAT signaling pathway; (bb) activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB); (cc) phosphorylation of ITAM motif-containing receptors; (dd) modulation of expression of one or more inflammatory receptors, optionally wherein the one or more inflammatory receptors comprise CD86; and the one or more inflammatory receptors are expressed on cells of microglia, macrophages, dendritic cells, bone marrow-derived dendritic cells, neutrophils, (ee) increasing expression of one or more TREM1-dependent genes; (gg) normalizing perturbed TREM1-dependent gene expression; (ff) increasing expression of one or more ITAM-dependent genes, optionally wherein the one or more ITAM-dependent genes are activated by nuclear factor of activated T cells (NFAT) transcription factor; (gg) increasing expression of one or more of immune suppressor dendritic cells, immune suppressor macrophages, myeloid-derived immune cells, or immune suppressor macrophages; (hh) activating the differentiation of one or more of immune suppressor dendritic cells, immune suppressor macrophages, myeloid-derived suppressor cells, tumor-associated macrophages, immune suppressor neutrophils, and regulatory T cells; (ii) activating the functionality of one or more of immune suppressor dendritic cells, immune suppressor macrophages, myeloid-derived suppressor cells, tumor-associated macrophages, immune suppressor neutrophils, and regulatory T cells. (jj) increasing the number of tumor-promoting myeloid / granulocytic immunosuppressive cells in tumors, peripheral blood or other lymphoid organs; (kk) stimulating the tumor-promoting activity of myeloid-derived suppressor cells; (ll) increasing the expression of tumor-promoting cytokines in tumors or in peripheral blood, optionally wherein the tumor-promoting cytokine is TGF-beta or IL-10; (mm) decreasing tumor infiltration of tumor-promoting FoxP3+ regulatory T lymphocytes;(nn) reducing activation of tumor-specific T lymphocytes capable of killing tumors, (oo) increasing tumor burden, (pp) increasing tumor growth rate, (qq) reducing the effectiveness of one or more immunotherapies that modulate anti-tumor T cell responses, optionally wherein the one or more immunotherapies are selected from PD1 / PDL1 blockade, CTLA-4 blockade and cancer vaccines, (rr) inhibiting PLCγ / PKC / calcium mobilization and (uu) inhibiting PI3K / Akt, Ras / MAPK signaling, (ss) inducing or maintaining TREM1 clustering on the cell surface, (xx) TREM1 binding to DAP12, (uu) TRE The effects of these may include one or more of the following: M1 phosphorylation, (vv) DAP12 phosphorylation, (ww) TREM1 phosphorylation, (xx) activation of one or more SRC family tyrosine kinases including Syk kinase, (yy) modulating the expression of one or more proteins selected from the group consisting of C1qa, C1qB, C1qC, C1s, C1R, C4, C2, C3, ITGB2, HMOX1, LAT2.CASP1, CSTA, VSIG4, MS4A4A, C3AR1, GPX1, TyroBP, ALOX5AP, ITGAM, SLC7A7, CD4, ITGAX, PYCARD, and VEGF1; (zz) increasing memory; and (aaa) reducing cognitive deficits.

[0156] In some embodiments, the antagonist antibody reduces survival of macrophages, microglial cells, M1 macrophages, M1 microglial cells, M2 macrophages, M2 microglial cells, osteoclasts, dermal Langerhans cells, Kupffer cells, and / or dendritic cells. In some embodiments, the antagonist antibody inhibits the interaction between TREM1 and one or more TREM1 ligands. In some embodiments, the antagonist antibody inhibits TREM1 signaling. In some embodiments, the antagonist antibody inhibits the interaction between TREM1 and one or more TREM1 ligands and inhibits TREM1 signaling. In some embodiments, the antagonist antibody inhibits TREM1 interaction with DAP12.

[0157] As described above, in some embodiments, the TREM1 antagonist antibody may inhibit the expression of one or more TREM1-dependent genes, including, but not limited to, one or more nuclear factor of activated T cells (NFAT) transcription factors.

[0158] The level of TREM1 (e.g., cellular level) in one or more cells can refer to, but is not limited to, the cell surface level of TREM1, the intracellular level of TREM1, and the total level of TREM1. In some embodiments, a reduction in the cellular level of TREM1 includes a reduction in the cell surface level of TREM1. As used herein, the cell surface level of TREM1 can be measured by any in vitro cell-based assay or suitable in vivo model described herein or known in the art, for example, using flow cytometry, such as fluorescence-activated cell sorting (FACS), to measure the cell surface level of TREM1. In some embodiments, a reduction in the level of TREM1 in a cell includes a reduction in the intracellular level of TREM1. As used herein, the intracellular level of TREM1 can be measured by any in vitro cell-based assay or suitable in vivo model described herein or known in the art, for example, immunostaining, Western blot analysis, co-immunoprecipitation, and cell counting. In some embodiments, a reduction in the cellular level of TREM1 includes a reduction in the total level of TREM1. As used herein, the total level of TREM1 can be measured by any in vitro cell-based assay or suitable in vivo model described herein or known in the art, such as immunostaining, Western blot analysis, co-immunoprecipitation, and cell counting. In some embodiments, the anti-TREM1 antibody induces TREM1 degradation, TREM1 cleavage, TREM1 internalization, TREM1 shedding, and / or downregulation of TREM1 expression. In some embodiments, the level of TREM1 in one or more cells (e.g., cellular level) is measured in primary cells (e.g., dendritic cells, bone marrow-derived dendritic cells, monocytes, microglia, and macrophages) or in cell lines using an in vitro cell assay.In some embodiments, the anti-TREM1 antibodies of the present disclosure reduce cellular levels of TREM1 by at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or more compared to cellular levels of TREM1 in the absence of the anti-TREM1 antibody. Any in vitro cell-based assay or suitable in vivo model described herein or known in the art can be used to measure inhibition of interaction (e.g., binding) between TREM1 and one or more TREM1 ligands. In some embodiments, the anti-TREM1 antibodies of the present disclosure inhibit the interaction (e.g., binding) between TREM1 and one or more TREM1 ligands by at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or more at saturating antibody concentrations using any in vitro or cell-based culture assay described herein or known in the art.

[0159] In some embodiments, the absence of antibody cross-linking is required for antagonist activity. In some embodiments, antibodies act as antagonists when presented as monomers and as agonists when presented as dimers or multimers. Antagonist antibodies may exert their activity by blocking receptor-ligand interactions.

[0160] Exemplary antagonist antibody Fc isotypes and modifications are provided below in Table B. In some embodiments, the antagonist antibody has an Fc isotype listed in Table B below.

[0161] Exemplary Fc Isotypes of Inactive and Antagonist Antibodies In some embodiments, the inactive and / or antagonist anti-TREM antibodies have an Fc isotype listed in Table B below. TIFF2024119791000007.tif232170TIFF2024119791000008.tif129170

[0162] In certain embodiments, the antibody has an IgG1 isotype. In some embodiments, the antibody contains a murine IgG1 constant region. In some embodiments, the antibody contains a human IgG1 constant region. In some embodiments, the human IgG1 constant region comprises an Fc region. In some embodiments, the Fc region contains one or more modifications. For example, in some embodiments, the Fc region contains one or more amino acid substitutions (e.g., relative to a wild-type Fc region of the same isotype). In some embodiments, the one or more amino acid substitutions are selected from the group consisting of N297A, N297Q (Bolt S et al. (1993) Eur J Immunol 23:403-411), D265A, L234A, L235A (McEarchern et al. (2007) Blood 109:1185-1192), C226S, C229S (McEarchern et al. (2007) Blood 109:1185-1192), P238S (Davis et al. (2007) J Rheumatol 34:2204-2210), E233P, L234V (McEarchern et al. (2007) Blood, 109:1185-1192), P238A, A327Q, A327G, P329A (Shields RL. et al., (2001) J Biol Chem. 276(9):6591-604), K322A, L234F, L235E (Hezareh et al., (2001) J Virol 75, 12161-12168; Oganesyan et al. (2008) Acta Crystallographica 64, 700-704), P331S (Oganesyan et al. (2008) Acta Crystallographica 64, 700-704), T394D (Wilkinson et al. (2013) MAbs 5(3): 406-417), A330L, M252Y, S254T, and / or T256E, where amino acid positions are according to the EU or Kabat numbering convention. In certain embodiments, the Fc region further comprises an amino acid deletion at a position corresponding to glycine 236 according to the EU or Kabat numbering convention.

[0163] In some embodiments, the antibody has an IgG1 isotype with a heavy chain constant region containing a C220S amino acid substitution according to the EU or Kabat numbering convention.

[0164] In some embodiments, the Fc region further contains one or more additional amino acid substitutions selected from A330L, L234F, L235E and / or P331S according to the EU or Kabat numbering convention.

[0165] In certain embodiments, the antibody has an IgG2 isotype. In some embodiments, the antibody comprises a human IgG2 constant region. In some embodiments, the human IgG2 constant region comprises an Fc region. In some embodiments, the Fc region contains one or more modifications. For example, in some embodiments, the Fc region contains one or more amino acid substitutions (e.g., relative to a wild-type Fc region of the same isotype). In some embodiments, the one or more amino acid substitutions are selected from V234A, G237A, H268E, V309L, N297A, N297Q, A330S, P331S, C232S, C233S, M252Y, S254T, and / or T256E, where amino acid positions are according to the EU or Kabat numbering convention.

[0166] In certain embodiments, the antibody has an IgG4 isotype. In some embodiments, the antibody comprises a human IgG4 constant region. In some embodiments, the human IgG4 constant region comprises an Fc region. In some embodiments, the Fc region contains one or more modifications. For example, in some embodiments, the Fc region contains one or more amino acid substitutions (e.g., relative to a wild-type Fc region of the same isotype). In some embodiments, the one or more amino acid substitutions are selected from E233P, F234V, L235A, G237A, E318A (Hutchins et al. (1995) Proc Natl Acad Sci USA, 92:11980-11984), S228P, L236E, S241P, L248E (Reddy et al. (2000) J Immunol, 164:1925-1933; Angal et al. (1993) Mol Immunol. 30(1):105-8; US8614299 B2), T394D, M252Y, S254T, T256E and / or N297A, N297Q, wherein the amino acid positions are according to the EU or Kabat numbering convention.

[0167] In some embodiments, the Fc region further contains one or more additional amino acid substitutions selected from M252Y, S254T, and / or T256E, where the amino acid positions are according to the EU or Kabat numbering convention.

[0168] Further IgG mutations In some embodiments, one or more of the IgG1 variants described herein may be combined with the A330L mutation (Lazar et al., (2006) Proc Natl Acad Sci USA, 103:4005-4010) or one or more of the L234F, L235E and / or P331S mutations (Sazinsky et al., (2008) Proc Natl Acad Sci USA, 105:20167-20172) to eliminate complement activation, where amino acid positions are according to EU or Kabat numbering conventions. In some embodiments, the IgG variants described herein may be combined with one or more mutations to enhance antibody half-life in human serum (e.g., M252Y, S254T, T256E mutations according to the EU or Kabat numbering convention) (Dall'Acqua et al., (2006) J Biol Chem, 281:23514-23524; and Strohl et al., (2009) Current Opinion in Biotechnology, 20:685-691).

[0169] In some embodiments, the IgG4 variants of the present disclosure may be combined with the S228P mutation according to the EU or Kabat numbering convention (Angal et al., (1993) Mol Immunol, 30:105-108) and / or with one or more mutations described in Peters et al., (2012) J Biol Chem. 13;287(29):24525-33) to enhance antibody stabilization.

[0170] Exemplary Anti-TREM1 Antibodies Anti-TREM1 antibodies of the present disclosure can be tested to induce or block one or more TREM1 activities as described in the sections above.

[0171] In some embodiments, the anti-TREM1 antibodies of the present disclosure are monoclonal antibodies.

[0172] In some embodiments, an isolated anti-TREM1 antibody of the present disclosure enhances one or more TREM1 activities induced by binding of one or more TREM1 ligands to a TREM1 protein compared to one or more TREM1 activities induced by binding of one or more TREM1 ligands to a TREM1 protein in the absence of the isolated antibody. In some embodiments, the anti-TREM1 antibody enhances one or more TREM1 activities without competing with or otherwise blocking the binding of one or more TREM1 ligands to a TREM1 protein. In some embodiments, the antibody is a human antibody, a humanized antibody, a bispecific antibody, a multivalent antibody, or a chimeric antibody. Exemplary descriptions of such antibodies are found throughout this disclosure. In some embodiments, the antibody is a bispecific antibody that recognizes a first antigen and a second antigen.

[0173] In some embodiments, the anti-TREM1 antibodies of the present disclosure are directed against mammalian TREM1 proteins, including, but not limited to, human TREM1 protein (Uniprot Accession No. Q9NP99, SEQ ID NO: 1), mouse TREM1 protein (Uniprot Accession No. Q9JKE2, SEQ ID NO: 2), rat TREM1 protein (Uniprot Accession No. D4ABU7, SEQ ID NO: 3), rhesus monkey TREM1 protein (Uniprot Accession No. F6TBB4, SEQ ID NO: 4), bovine TREM1 protein (Uniprot Accession No. H6TBB1, SEQ ID NO: 5), rat TREM1 protein (Uniprot Accession No. H6TBB2, SEQ ID NO: 6), rat TREM1 protein (Uniprot Accession No. H6TBB3, SEQ ID NO: 7), rat TREM1 protein (Uniprot Accession No. H6TBB4, SEQ ID NO: 8), rat TREM1 protein (Uniprot Accession No. H6TBB1, SEQ ID NO: 9), rat TREM1 protein (Uniprot Accession No. H6TBB1, SEQ ID NO: 10), rat TREM1 protein (Uniprot Accession No. H6TBB1, SEQ ID NO: 11), rat TREM1 protein (Uniprot Accession No. H6TBB1, SEQ ID NO: 12), rat TREM1 protein (Uniprot Accession No. H6TBB1, SEQ ID NO: 13), rat TREM1 protein (Uniprot Accession No. H6TBB1, SEQ ID NO: 14), rat TREM1 protein (Uniprot Accession No. H6TBB1, SEQ ID NO: 15), rat TREM1 protein (Uniprot Accession No. H6TBB1, SEQ ID NO: 16), rat TREM1 protein (Uniprot Accession No. H6TBB1, SEQ ID NO: 17), rat TREM1 protein (Uni The anti-TREM1 antibodies of the present disclosure bind to human TREM1 or homologs thereof, including the TREM1 protein (Uniprot Accession No. Q6QUN5, SEQ ID NO: 5), the horse TREM1 protein (Uniprot Accession No. F6PSF7, SEQ ID NO: 6), the pig TREM1 protein (Uniprot Accession No. R4SEY7, SEQ ID NO: 7), the chimpanzee TREM1 protein (Uniprot Accession No. H2QSZ3, SEQ ID NO: 561), and the dog TREM1 protein (Uniprot Accession No. E2RP37, SEQ ID NO: 8). In some embodiments, the anti-TREM1 antibodies of the present disclosure specifically bind to human TREM1. In some embodiments, the anti-TREM1 antibodies of the present disclosure specifically bind to mouse TREM1. In some embodiments, the anti-TREM1 antibodies of the present disclosure specifically bind to both human TREM1 and mouse TREM1. In some embodiments, the anti-TREM1 antibodies of the present disclosure modulate (e.g., induce or inhibit) at least one TREM1 activity as described herein.

[0174] In some embodiments, the anti-TREM1 antibodies of the present disclosure bind to membrane-bound or soluble forms and / or naturally occurring variants of the TREM1 proteins of the present disclosure. In certain preferred embodiments, the anti-TREM1 antibodies bind to human TREM1.

[0175] In some embodiments, the anti-TREM1 antibodies of the present disclosure are agonist or antagonist antibodies that bind to a TREM1 protein of the present disclosure expressed on the surface of a cell and modulate (e.g., induce or inhibit) at least one TREM1 activity of the present disclosure after binding to the surface-expressed TREM1 protein. In some embodiments, the anti-TREM1 antibodies of the present disclosure are inactive antibodies.

[0176] Exemplary assays for assessing antibody binding to TREM1 and the effect of anti-TREM1 antibodies on TREM1-mediated activity are provided in the Examples section.

[0177] Anti-TREM1 antibody-binding region Certain aspects of the disclosure provide anti-TREM1 antibodies that bind to one or more amino acids within amino acid residues 21-205 of human TREM1 (SEQ ID NO: 1), or within amino acid residues on a TREM1 homolog or orthologue corresponding to amino acid residues 21-205 of SEQ ID NO: 1. In some embodiments, the anti-TREM1 antibodies bind to one or more amino acids within amino acid residues 26-134 of human TREM1 (SEQ ID NO: 1), or within amino acid residues on a TREM1 homolog or orthologue corresponding to amino acid residues 26-134 of SEQ ID NO: 1. In some embodiments, the anti-TREM1 antibodies bind to one or more amino acids within amino acid residues 45-54 of human TREM1 (SEQ ID NO: 1), or within amino acid residues on a TREM1 homolog or orthologue corresponding to amino acid residues 45-54 of SEQ ID NO: 1. In some embodiments, the anti-TREM1 antibody binds to one or more amino acids within amino acid residues 70-79 of human TREM1 (SEQ ID NO: 1), or within amino acid residues on a TREM1 homolog or orthologue corresponding to amino acid residues 70-79 of SEQ ID NO: 1. In some embodiments, the anti-TREM1 antibody binds to one or more amino acids within amino acid residues 89-97 of human TREM1 (SEQ ID NO: 1), or within amino acid residues on a TREM1 homolog or orthologue corresponding to amino acid residues 89-97 of SEQ ID NO: 1. In some embodiments, the anti-TREM1 antibody binds to one or more amino acids within amino acid residues 119-125 of human TREM1 (SEQ ID NO: 1), or within amino acid residues on a TREM1 homolog or orthologue corresponding to amino acid residues 119-125 of SEQ ID NO: 1. In some embodiments, the anti-TREM1 antibody binds to one or more amino acids within amino acid residues 83-90 of human TREM1 (SEQ ID NO: 1), or within amino acid residues on a TREM1 homolog or orthologue corresponding to amino acid residues 83-90 of SEQ ID NO: 1. In some embodiments, the anti-TREM1 antibody binds to one or more amino acids within amino acid residues 191-201 of human TREM1 (SEQ ID NO: 1), or within amino acid residues on a TREM1 homolog or orthologue corresponding to amino acid residues 191-201 of SEQ ID NO: 1.In some embodiments, the anti-TREM1 antibody binds to one or more amino acids within amino acid residues 116-125 of human TREM1 (SEQ ID NO: 1) or within amino acid residues on a TREM1 homolog or ortholog corresponding to amino acid residues 116-125 of SEQ ID NO: 1.

[0178] In some embodiments, an anti-TREM1 antibody of the disclosure competitively inhibits the binding of at least one antibody selected from any of the antibodies listed in Tables 2-5. In some embodiments, an anti-TREM1 antibody of the disclosure competitively inhibits the binding of at least one antibody selected from T1-1-T1-80 or at least one antibody selected from T1-1-T1-25 and T1-33 and -T1-80.

[0179] In some embodiments, an anti-TREM1 antibody of the present disclosure binds to an epitope on human TREM1 that is identical to or overlaps with a TREM1 epitope bound by at least one antibody selected from any of the antibodies listed in Tables 2-5. In some embodiments, an anti-TREM1 antibody of the present disclosure binds to an epitope on human TREM1 that is identical to or overlaps with a TREM1 epitope bound by at least one antibody selected from T1-1-T1-80 or at least one antibody selected from T1-1-T1-25 and T1-33 and -T1-80.

[0180] In some embodiments, an anti-TREM1 antibody of the present disclosure binds essentially the same TREM1 epitope bound by at least one antibody selected from any of the antibodies listed in Tables 2-5. In some embodiments, an anti-TREM1 antibody of the present disclosure binds essentially the same TREM1 epitope bound by at least one antibody selected from T1-1-T1-80 or at least one antibody selected from T1-1-T1-25 and T1-33 and -T1-80. Detailed exemplary methods for mapping antibody-binding epitopes are provided in Morris (1996) "Epitope Mapping Protocols," in Methods in Molecular Biology, Vol. 66 (Humana Press, Totowa, NJ) and in Example 2 of the present disclosure. In some embodiments, an anti-TREM1 antibody of the present disclosure binds essentially the same epitope as T1-62 or essentially the same epitope as T1-63. In some embodiments, an anti-TREM1 antibody of the disclosure binds essentially the same epitope as T1-34, essentially the same epitope as T1-39, or essentially the same epitope as T1-40. In some embodiments, an anti-TREM1 antibody of the disclosure binds an epitope including amino acids 83-90 and 191-201 of SEQ ID NO: 1. In some embodiments, an anti-TREM1 antibody binds an epitope including amino acids 45-54, 70-79, 89-97, and 119-125 of SEQ ID NO: 1.

[0181] In some embodiments, an anti-TREM1 antibody of the present disclosure competes for binding to TREM1 with one or more antibodies selected from T1-1-T1-80. In some embodiments, an anti-TREM1 antibody of the present disclosure competes for binding to TREM1 with one or more antibodies selected from T1-1-T1-25 and T1-33-T1-80. In some embodiments, an anti-TREM1 antibody of the present disclosure competes for binding to TREM1 with T1-62. In some embodiments, an anti-TREM1 antibody of the present disclosure competes with T1-63 for binding to TREM1. In some embodiments, an anti-TREM1 antibody of the present disclosure competes with T1-34 for binding to TREM1. In some embodiments, an anti-TREM1 antibody of the present disclosure competes with T1-39 for binding to TREM1. In some embodiments, an anti-TREM1 antibody of the present disclosure competes with T1-40 for binding to TREM1.

[0182] In an exemplary competition assay, immobilized TREM1 or cells expressing TREM1 on the cell surface are incubated in a solution containing a first labeled antibody that binds to TREM1 (e.g., human or non-human primate) and a second unlabeled antibody being tested for its ability to compete with the first antibody for binding to TREM1. The second antibody may be present in hybridoma supernatant. As a control, immobilized TREM1 or cells expressing TREM1 are incubated in a solution containing the first labeled antibody but not the second unlabeled antibody. After incubation under permissive conditions for binding of the first antibody to TREM1, excess unbound antibody is removed and the amount of label associated with the immobilized TREM1 or cells expressing TREM1 is measured. If the amount of label associated with the immobilized TREM1 or cells expressing TREM1 is substantially reduced in the test sample compared to the control sample, this indicates that the second antibody competes with the first antibody for binding to TREM1. See Harlow and Lane (1988) Antibodies: A Laboratory Manual, Chapter 14 (Cold Spring Harbor Laboratory, Cold Spring Harbor, NY).

[0183] Anti-TREM1 antibody light and heavy chain variable regions In some embodiments, the anti-TREM1 antibodies of the present disclosure comprise (a) a light chain variable region comprising at least one, two, or three HVRs selected from HVR-L1, HVR-L2, and HVR-L3 of any one of the antibodies listed in Table 2-5, or selected from T1-1-T1-80, or selected from T1-1-T1-25 and T1-33-T1-80, and any combination thereof; and / or (b) a heavy chain variable region comprising at least one, two, or three HVRs selected from HVR-H1, HVR-H2, and HVR-H3 of any one of the antibodies listed in Table 2-5, or selected from T1-1-T1-80, and any combination thereof. In some embodiments, HVR-L1, HVR-L2, HVR-L3, HVR-H1, HVR-H2, and HVR-H3 comprise EU or Kabat HVR, Chothia HVR, or contact HVR sequences derived from an antibody as set forth in Tables 2-5, or selected from T1-1-T1-80, and any combination thereof, or an antibody selected from T1-1-T1-25 and T1-33-T1-80, and any combination thereof.

[0184] In some embodiments, the anti-TREM1 antibodies of the present disclosure comprise: (i) an HVR-L1 comprising the amino acid sequence of any of the HVR-L1 sequences derived from an antibody listed in Table 2-5, or selected from T1-1-T1-80, or selected from T1-1-T1-25 and T1-33-T1-80; (ii) an HVR-L2 comprising the amino acid sequence of any of the HVR-L2 sequences derived from an antibody listed in Table 2-5, or selected from T1-1-T1-80, or selected from T1-1-T1-25 and T1-33-T1-80; (iii) an HVR-L3 comprising the amino acid sequence of any of the HVR-L3 sequences derived from an antibody listed in Table 2-5, or selected from T1-1-T1-80, or selected from T1-1-T1-25 and T1-33-T1-80; and (vi) an HVR-H3 comprising the amino acid sequence of any of the HVR-H3 sequences derived from an antibody listed in Table 2-5 or selected from T1-1-T1-80 or selected from T1-1-T1-25 and T1-33-T1-80.

[0185] In some embodiments, an anti-TREM1 antibody of the disclosure comprises a light chain variable domain and a heavy chain variable domain, wherein the light chain variable domain comprises: (a) HVR-L1 comprising an amino acid sequence selected from SEQ ID NOs: 9-27 or an amino acid sequence having at least about 90% identity to an amino acid sequence selected from SEQ ID NOs: 9-27; (b) HVR-L2 comprising an amino acid sequence selected from SEQ ID NOs: 28-40 or an amino acid sequence having at least about 90% identity to an amino acid sequence selected from SEQ ID NOs: 28-40; and (c) HVR-L3 comprising an amino acid sequence selected from SEQ ID NOs: 41-119 or an amino acid sequence having at least about 90% identity to an amino acid sequence selected from SEQ ID NOs: 41-119. and / or the heavy chain variable domain comprises one or more of: (a) HVR-H1 comprising an amino acid sequence selected from SEQ ID NOs: 120-143 or an amino acid sequence having at least about 90% identity to an amino acid sequence selected from SEQ ID NOs: 120-143; (b) HVR-H2 comprising an amino acid sequence selected from SEQ ID NOs: 144-172 or an amino acid sequence having at least about 90% identity to an amino acid sequence selected from SEQ ID NOs: 144-172; and (c) HVR-H3 comprising an amino acid sequence selected from SEQ ID NOs: 173-247 or an amino acid sequence having at least about 90% identity to an amino acid sequence selected from SEQ ID NOs: 173-247.

[0186] In some embodiments, an anti-TREM1 antibody of the disclosure comprises a light chain variable region of any one of the antibodies listed in Tables 2-5, or selected from T1-1-T1-80, or selected from T1-1-T1-25 and T1-33-T1-80, and / or a heavy chain variable region of any one of the antibodies listed in Tables 2-5, or selected from T1-1-T1-80, or selected from T1-1-T1-25 and T1-33-T1-80. In some embodiments, an anti-TREM1 antibody of the disclosure comprises a light chain variable region comprising an amino acid sequence selected from any of SEQ ID NOs: 316-395 and / or a heavy chain variable domain comprising an amino acid sequence selected from any of SEQ ID NOs: 396-475.

[0187] In some embodiments, an anti-TREM1 antibody of the disclosure that enhances TREM1 activity comprises a heavy chain HVR3 comprising the sequence ARGPSWIDV (SEQ ID NO: 477), a heavy chain HVR1 comprising the consensus sequence SISS-GYYW (SEQ ID NO: 478), and / or a heavy chain HVR2 antigen contact region comprising the consensus sequence WIG(S / Y)IYSGxTYY (SEQ ID NO: 479), where "WIG" is the C-terminal amino acid sequence of heavy chain FR2. In some embodiments, an anti-TREM1 antibody of the disclosure that enhances TREM1 activity comprises a heavy chain HVR3 comprising the sequence ARELYAYSSPMFYGMDV (SEQ ID NO: 480), a heavy chain HVR1 comprising the consensus sequence SISS-GYYW (SEQ ID NO: 478), and / or a heavy chain HVR2 antigen contact region comprising the consensus sequence WIG(S / Y)IYSGxTYY (SEQ ID NO: 479), where "WIG" is the C-terminal amino acid sequence of heavy chain FR2. In some embodiments, an anti-TREM1 antibody of the disclosure that enhances TREM1 activity comprises a light chain HVR3 comprising the sequence QQDVSDFT (SEQ ID NO: 481), a light chain HVR1 comprising the consensus sequence QS(I / V)S (SEQ ID NO: 482), and / or a light chain HVR2 antigen contact region comprising the consensus sequence LLIY(G / A)ASS (SEQ ID NO: 483), wherein "LLIY" (SEQ ID NO: 484) is the C-terminal amino acid sequence of light chain FR2. In some embodiments, an anti-TREM1 antibody of the disclosure that enhances TREM1 activity comprises a light chain HVR3 comprising the sequence QQLYHAPPIT (SEQ ID NO: 485), a light chain HVR1 comprising the consensus sequence QS(I / V)S (SEQ ID NO: 482), and / or a light chain HVR2 antigen contact region comprising the consensus sequence LLIY(G / A)ASS (SEQ ID NO: 483), wherein "LLIY" (SEQ ID NO: 484) is the C-terminal amino acid sequence of light chain FR2.In some embodiments, an antibody that enhances TREM1 activity comprises a heavy chain HVR3 comprising the sequence ARGPSWIDV (SEQ ID NO: 477) or ARELYAYSSPMFYGMDV (SEQ ID NO: 481), a heavy chain HVR1 comprising the consensus sequence SISS-GYYW (SEQ ID NO: 478), a heavy chain HVR2 antigen contact region comprising the consensus sequence WIG(S / Y)IYxSGxTYY (SEQ ID NO: 479), where "WIG" is the C-terminal amino acid sequence of heavy chain FR2, a light chain HVR3 comprising the sequence QQDVSDFT (SEQ ID NO: 481) or QQLYHAPPIT (SEQ ID NO: 485), a light chain HVR1 sequence comprising the consensus sequence QS(I / V)S (SEQ ID NO: 482), and a light chain HVR2 antigen contact region comprising the consensus sequence LLIY(G / A)ASS (SEQ ID NO: 483), and "LLIY" (SEQ ID NO: 484) is the C-terminal amino acid sequence of light chain FR2.

[0188] In some embodiments, an anti-TREM1 antibody that enhances TREM1 activity has six HVRs, T1-62 or T1-63. Thus, in some embodiments, the antibody has a light chain HVR1 comprising SEQ ID NO: 10, a light chain HVR2 comprising SEQ ID NO: 29, a light chain HVR3 comprising SEQ ID NO: 101, a heavy chain HVR1 comprising SEQ ID NO: 130, a heavy chain HVR2 comprising SEQ ID NO: 159, and a heavy chain HVR3 comprising SEQ ID NO: 229. In some embodiments, the antibody has a light chain HVR1 comprising SEQ ID NO: 23, a light chain HVR2 comprising SEQ ID NO: 34, a light chain HVR3 comprising SEQ ID NO: 102, a heavy chain HVR1 comprising SEQ ID NO: 136, a heavy chain HVR2 comprising SEQ ID NO: 168, and a heavy chain HVR3 comprising SEQ ID NO: 230.

[0189] In some embodiments, an anti-TREM1 antibody that antagonizes TREM1 activity comprises a heavy chain HVR3 comprising the sequence ARRPDDRRGLFQH (SEQ ID NO: 486), a heavy chain HVR1 comprising the consensus sequence FTFS(S / T)YSMN (SEQ ID NO: 487), and / or a heavy chain HVR2 antigen contact region comprising the consensus sequence WVSSISSSSxYIYY (SEQ ID NO: 488), where "WV" is the C-terminal amino acid sequence of heavy chain FR2. In some embodiments, an anti-TREM1 antibody that antagonizes TREM1 activity comprises a heavy chain HVR3 comprising the sequence ARRGGSSSTGLLY (SEQ ID NO: 489), a heavy chain HVR1 comprising the consensus sequence FTFS(S / T)YSMN (SEQ ID NO: 487), and / or a heavy chain HVR2 antigen contact region comprising the consensus sequence WVSSISSSSxYIYY (SEQ ID NO: 488), where "WV" is the C-terminal amino acid sequence of heavy chain FR2. In some embodiments, an anti-TREM1 antibody that antagonizes TREM1 activity comprises a heavy chain HVR3 comprising the sequence ARTRIDDSFDI (SEQ ID NO: 490), a heavy chain HVR1 comprising the consensus sequence FTFS(S / T)YSMN (SEQ ID NO: 488), and / or a heavy chain HVR2 antigen contact region comprising the consensus sequence WVSSISSSSxYIYY (SEQ ID NO: 488), where "WV" is the C-terminal amino acid sequence of heavy chain FR2.

[0190] In some embodiments, an anti-TREM1 antibody that antagonizes TREM1 activity comprises a light chain HVR3 comprising QQYGPYPYT (SEQ ID NO: 491), a light chain HVR1 comprising the consensus sequence Q(S / D)ISSWLA (SEQ ID NO: 492), and / or a light chain HVR2 antigen contact region comprising the consensus sequence LLIY(D / A)ASSL(E / Q)S (SEQ ID NO: 493), wherein "LLIY" (SEQ ID NO: 484) is the C-terminal amino acid sequence of light chain FR2. In some embodiments, an anti-TREM1 antibody that antagonizes TREM1 activity comprises a light chain HVR3 comprising QQSLTHPT (SEQ ID NO: 494), a light chain HVR1 comprising the consensus sequence Q(S / D)ISSWLA (SEQ ID NO: 492), and / or a light chain HVR2 antigen contact region comprising the consensus sequence LLIY(D / A)ASSL(E / Q)S (SEQ ID NO: 493), wherein "LLIY" (SEQ ID NO: 484) is the C-terminal amino acid sequence of light chain FR2. In some embodiments, an anti-TREM1 antibody that antagonizes TREM1 activity comprises a light chain HVR3 comprising AAQDLLPYT (SEQ ID NO: 495), a light chain HVR1 comprising the consensus sequence Q(S / D)ISSWLA (SEQ ID NO: 492), and / or a light chain HVR2 antigen contact region comprising the consensus sequence LLIY(D / A)ASSL(E / Q)S (SEQ ID NO: 493), wherein "LLIY" (SEQ ID NO: 484) is the C-terminal amino acid sequence of light chain FR2.

[0191] In some embodiments, an anti-TREM1 antibody that antagonizes TREM1 activity comprises a heavy chain HVR3 comprising the sequence ARRPDDRRGLFQH (SEQ ID NO: 496) or ARRGGSSSTGLLY (SEQ ID NO: 489), a heavy chain HVR1 comprising the consensus sequence FTFS(S / T)YSMN (SEQ ID NO: 487), and a heavy chain HVR2 antigen contact region comprising the consensus sequence WVSSISSSSxYIYY (SEQ ID NO: 488), where "WV" represents the C-terminal amino acid sequence of heavy chain FR2. The light chain HVR3 has the amino acid sequence QQYGPYPYT (SEQ ID NO: 491), QQSLTHPT (SEQ ID NO: 494), or AAQDLLPYT (SEQ ID NO: 495), the light chain HVR1 has the consensus sequence Q(S / D)ISSWLA (SEQ ID NO: 492), and the light chain HVR2 has the consensus sequence LLIY(D / A)ASSL(E / Q)S (SEQ ID NO: 493), and the antigen contact region "LLIY" (SEQ ID NO: 484) is the C-terminal amino acid sequence of light chain FR2.

[0192] In some embodiments, an anti-TREM1 antibody that antagonizes TREM1 activity has six HVRs: T1-34, T1-39, or T1-40. Thus, in some embodiments, the antibody has a light chain HVR1 comprising SEQ ID NO:24, a light chain HVR2 comprising SEQ ID NO:38, a light chain HVR3 comprising SEQ ID NO:73, a heavy chain HVR1 comprising SEQ ID NO:123, a heavy chain HVR2 comprising SEQ ID NO:148, and a heavy chain HVR3 comprising SEQ ID NO:205. In some embodiments, the antibody has a light chain HVR1 comprising SEQ ID NO:25, a light chain HVR2 comprising SEQ ID NO:34, a light chain HVR3 comprising SEQ ID NO:78, a heavy chain HVR1 comprising SEQ ID NO:123, a heavy chain HVR2 comprising SEQ ID NO:148, and a heavy chain HVR3 comprising SEQ ID NO:209. In some embodiments, the antibody has a light chain HVR1 comprising SEQ ID NO: 14, a light chain HVR2 comprising SEQ ID NO: 30, a light chain HVR3 comprising SEQ ID NO: 79, a heavy chain HVR1 comprising SEQ ID NO: 123, a heavy chain HVR2 comprising SEQ ID NO: 50, and a heavy chain HVR3 comprising SEQ ID NO: 210.

[0193] In some embodiments, an anti-TREM1 antibody of the disclosure has a heavy chain CDR1 sequence in which position X in CDR1 is G or A as shown in the heavy chain sequence of the ligand-enhanced antibody in Figure 14. In some embodiments, the antibody has a heavy chain CDR2 sequence in which position X in CDR2 is S or N as shown in the heavy chain sequence of the ligand-enhanced antibody in Figure 14. In some embodiments, the heavy chain variable region comprises the FR1 to FR3 sequence of a ligand-enhanced antibody as shown in Figure 14. In some embodiments, an anti-TREM1 antibody of the disclosure has a heavy chain variable region sequence comprising the FR1 to CDR3 sequence of a ligand-enhanced antibody as shown in Figure 14. In some embodiments, an anti-TREM1 antibody comprises a heavy chain variable region comprising the VH4-0B*01 or VH4-31*01 sequence as shown in Figure 14.

[0194] In some embodiments, an anti-TREM1 antibody of the disclosure has a heavy chain CDR2 sequence in which position X in CDR2 is S or N as shown in the heavy chain sequence of the antagonist antibody in Figure 14. In some embodiments, the heavy chain variable region comprises the FR1 to FR3 sequence of the antagonist antibody as shown in Figure 14. In some embodiments, an anti-TREM1 antibody of the disclosure has a heavy chain variable region sequence comprising the FR1 to CDR3 sequence of the antagonist antibody as shown in Figure 14. In some embodiments, an anti-TREM1 antibody comprises a heavy chain variable region comprising the VH3-21*01 sequence as shown in Figure 14.

[0195] In some embodiments, an anti-TREM1 antibody of the disclosure has a heavy chain CDR2 sequence in which position X of CDR2 is S or T, and position Z of CDR2 is S or D, as shown in the heavy chain sequence of the ligand mimetic antibody in Figure 14. In some embodiments, the heavy chain variable region comprises the FR1 to FR3 sequence of a ligand mimetic antibody as shown in Figure 14. In some embodiments, an anti-TREM1 antibody of the disclosure has a heavy chain variable region sequence comprising the FR1 to CDR3 sequence of a ligand mimetic antibody as shown in Figure 14. In some embodiments, an anti-TREM1 antibody comprises a heavy chain variable region comprising the VH3-09*01 sequence as shown in Figure 14.

[0196] In some embodiments, an anti-TREM1 antibody of the present disclosure has a heavy chain CDR1 sequence in which position X of CDR1 is S or N as shown in the heavy chain sequence in the VH1-69*01 section of Figure 15, and position X of CDR2 is S or N as shown in the heavy chain sequence in the VH1-69*01 section of Figure 15. In some embodiments, an anti-TREM1 antibody of the present disclosure has a heavy chain CDR1 sequence in which position X of CDR1 is S or H as shown in the heavy chain sequence in the VH1-18*01 section of Figure 15. In some embodiments, an anti-TREM1 antibody of the present disclosure has a heavy chain CDR1 sequence in which position X of CDR1 is M or I as shown in the heavy chain sequence in the VH1-02*02 section of Figure 15, and position X of CDR2 is I or V as shown in the heavy chain sequence in the VH1-02*02 section of Figure 15. In some embodiments, an anti-TREM1 antibody of the disclosure has a heavy chain CDR1 sequence in which position X of CDR1 as shown in the heavy chain sequence in the VH4-0B*01 section in Figure 15 is G or A, and position X of CDR2 as shown in the heavy chain sequence in the VH4-0B*01 section in Figure 15 is S or N. In some embodiments, an anti-TREM1 antibody of the disclosure has a heavy chain CDR1 sequence in which position X of CDR1 as shown in the heavy chain sequence in the VH4-39*01 section in Figure 15 is S or D, and position X of CDR2 as shown in the heavy chain sequence in the VH4-39*01 section in Figure 15 is Y or S. In some embodiments, an anti-TREM1 antibody of the present disclosure has a heavy chain CDR1 sequence in which position X of CDR1 as shown in the heavy chain sequence in the section VH3-33*01 in Figure 15 is S or N, position X of CDR2 as shown in the heavy chain sequence in the section VH3-33*01 in Figure 15 is V or L, and position Z of CDR2 as shown in the heavy chain sequence in the section VH3-33*01 in Figure 15 is Y or G.In some embodiments, an anti-TREM1 antibody of the present disclosure has a heavy chain CDR1 sequence in which position X of CDR1 is F or L as shown in the heavy chain sequence in the VH3-30*03 section in Figure 15. In some embodiments, an anti-TREM1 antibody of the present disclosure has a heavy chain CDR2 sequence in which position X of CDR2 is S or T and position Z is S or D as shown in the heavy chain sequence in the VH3-09*01 section in Figure 15. In some embodiments, an anti-TREM1 antibody of the present disclosure has a heavy chain CDR2 sequence in which position X of CDR2 is S or N as shown in the heavy chain sequence in the VH3-21*01 section in Figure 15. In some embodiments, an anti-TREM1 antibody of the present disclosure has a heavy chain CDR1 sequence in which position X of CDR1 is S or T as shown in the heavy chain sequence in the VH3-23*01 section in the figure. In some embodiments, the heavy chain variable region comprises the FR1 to FR3 sequence as shown in Figure 15. In some embodiments, the anti-TREM1 antibodies of the disclosure have a heavy chain variable region sequence comprising the FR1 to CDR3 sequence as shown in Figure 15.

[0197] In some embodiments, an anti-TREM1 antibody of the disclosure has a light chain CDR1 sequence in which position X in CDR1 is S or R as shown in the light chain sequence in the VK2-28*01 section of Figure 16, and position X in CDR2 is N or H as shown in the light chain sequence in the VK2-28*01 section of Figure 16. In some embodiments, an anti-TREM1 antibody of the disclosure has a light chain CDR2 sequence in which position X in CDR2 is E or A as shown in the light chain sequence in the VK1-33*01 section of Figure 16. In some embodiments, an anti-TREM1 antibody of the disclosure has a light chain CDR1 sequence in which position X in CDR1 is S or N as shown in the light chain sequence in the VK1-05*01 section of Figure 16, and position X in CDR2 is Y or S as shown in the light chain sequence in the VK1-05*01 section. In some embodiments, an anti-TREM1 antibody of the disclosure has a light chain CDR1 sequence in which position X of CDR1 is S or G as shown in the light chain sequence in the VK1-05*0 section in Figure 16. In some embodiments, an anti-TREM1 antibody of the disclosure has a light chain CDR1 sequence in which position X of CDR1 is G or D and position z is S or D as shown in the light chain sequence in the VK1-12*01 section in Figure 16, and position X of CDR2 is S or N as shown in the light chain sequence in the VK1-12*01 section in Figure 16. In some embodiments, an anti-TREM1 antibody of the disclosure has a light chain CDR1 sequence in which position X of CDR1 is S or R and position z is Y or F as shown in the light chain sequence in the VK1-39*01 section in Figure 16. In some embodiments, an anti-TREM1 antibody of the disclosure has a light chain CDR1 sequence in which position X in CDR1 is Y or F as shown in the light chain sequence in the VK4-01*01 section in Figure 16. In some embodiments, an anti-TREM1 antibody of the disclosure has a light chain CDR1 sequence in which position X in CDR1 is Y or F as shown in the light chain sequence in the VK3-20*01 section in Figure 16.In some embodiments, an anti-TREM1 antibody of the disclosure has a light chain CDR1 sequence in which position X in CDR1 is S or G as shown in the light chain sequence in the VK3-15*01 section in Figure 16. In some embodiments, an anti-TREM1 antibody of the disclosure has a light chain CDR2 sequence in which position X in CDR2 is A or S as shown in the light chain sequence in the VK3-11*01 section in Figure 16. In some embodiments, the light chain variable region comprises the FR1 to FR3 sequences as shown in Figure 16. In some embodiments, an anti-TREM1 antibody of the disclosure has a light chain variable region sequence comprising the FR1 to CDR3 sequences as shown in Figure 16.

[0198] Any of the antibodies of the present disclosure may be produced by a cell line. In some embodiments, the cell line may be a mammalian cell line. In certain embodiments, the cell line may be a hybridoma cell line. In other embodiments, the cell line may be a yeast cell line. Any cell line known in the art that is suitable for antibody production may be used to produce the antibodies of the present disclosure. Exemplary cell lines for antibody production are described throughout this disclosure.

[0199] In some embodiments, the anti-TREM1 antibody is an anti-TREM1 monoclonal antibody selected from T1-1-T1-80 and humanized variants thereof. In certain embodiments, the anti-TREM1 antibody is an agonist antibody. In certain embodiments, the anti-TREM1 antibody is an inactive antibody. In certain embodiments, the anti-TREM1 antibody is an antagonist antibody.

[0200] In some embodiments, the anti-TREM1 antibody is one or more anti-TREM1 monoclonal antibodies listed in Table 1A, Table 1B, or Tables 2-5. In some embodiments, the anti-TREM1 antibody is an isolated antibody that binds to essentially the same TREM1 epitope as one or more anti-TREM1 monoclonal antibodies listed in Table 1A, Table 1B, or Tables 2-5. In some embodiments, the anti-TREM1 antibody is an isolated antibody comprising the heavy chain variable domain HVR-H1, HVR-H2, and HVR-H3 of monoclonal antibody T1-1-T1-80. In some embodiments, the anti-TREM1 antibody is an isolated antibody comprising the light chain variable domain HVR-L1, HVR-L2, and HVR-L3 of monoclonal antibody T1-1-T1-80. In some embodiments, the anti-TREM1 antibody is an isolated antibody comprising at least one heavy chain variable domain HVR-H1, HVR-H2, and HVR-H3 and light chain variable domain HVR-L1, HVR-L2, and HVR-L3 of monoclonal antibody T1-1-T1-80.

[0201] In some embodiments, the anti-TREM1 antibody is an isolated antibody that binds to essentially the same TREM1 epitope as at least one of monoclonal antibodies T1-1-T1-80.

[0202] In some embodiments, the anti-TREM1 antibodies of the present disclosure do not compete with one or more TREM1 ligands for binding to TREM1. In some embodiments, the anti-TREM1 antibodies of the present disclosure are capable of binding to TREM1 without blocking the simultaneous binding of one or more TREM1 ligands to TREM1. In some embodiments, the anti-TREM1 antibodies of the present disclosure are capable of additive and / or synergistic functional interactions with one or more TREM1 ligands. In some embodiments, the anti-TREM1 antibodies of the present disclosure increase the maximal activity of TREM1 exposed to saturating concentrations of one or more TREM1 ligands. In some embodiments, the anti-TREM1 antibodies of the present disclosure increase the activity of TREM1 obtained with any concentration of one or more TREM1 ligands.

[0203] Anti-TREM1 antibody binding affinity Dissociation constants (K ) of anti-TREM1 antibodies for human TREM1 and mouse TREM1 D) is less than 15nM, less than 14.5nM, less than 14nM, less than 13.5nM, less than 13nM, less than 12.9nM, less than 12.8nM, less than 12.7nM, less than 12.6nM, less than 12.5nM, less than 12.4nM, less than 12.3nM, less than 12.2nM, less than 12.1nM, less than 12nM, less than 11.5nM, less than 11nM, less than 10.9n Less than 10.8nM, Less than 10.7nM, Less than 10.6nM, Less than 10.5nM, Less than 10.4nM, Less than 10.3nM, Less than 10.2nM, Less than 10.1nM, Less than 10nM, Less than 9.5nM, Less than 9nM, Less than 8.5nM, Less than 8nM, Less than 7.5nM, Less than 7nM, Less than 6.9nM, Less than 6.8nM, Less than 6.7nM, Less than 6.6 Less than nM, Less than 6.5 nM, Less than 6.4 nM, Less than 6.3 nM, Less than 6.2 nM, Less than 6.1 nM, Less than 6 nM, Less than 5.5 nM, Less than 5 nM, Less than 4.5 nM, Less than 4 nM, Less than 3.5 nM, Less than 3.4 nM, Less than 3.3 nM, Less than 3.2 nM, Less than 3.1 nM, Less than 3 nM, Less than 2.9 nM, Less than 2.8 nM, Less than 2.7 nM, Less than 2.6 The dissociation constant may be less than 2.5 nM, less than 2.4 nM, less than 2.3 nM, less than 2.2 nM, less than 2.1 nM, less than 2 nM, less than 1.9 nM, less than 1.8 nM, less than 1.7 nM, less than 1.6 nM, less than 1.5 nM, less than 1.4 nM, less than 1.3 nM, less than 1.2 nM, less than 1.1 nM, less than 1 nM, less than 0.95 nM, or less than 0.9 nM. In some embodiments, the dissociation constant is in the range of about 12.8 nM to about 1.2 nM or less than 1.2 nM. In some embodiments, the dissociation constant of the anti-TREM1 antibody for human TREM1 is in the range of about 12.8 nM to about 2.9 nM or less than 2.9 nM. In some embodiments, the dissociation constant of an anti-TREM1 antibody against mouse TREM1 ranges from about 10.4 nM to about 1.2 nM or less. The dissociation constant can be determined by any analytical technique, including any biochemical or biophysical technique, such as ELISA, surface plasmon resonance (SPR), biolayer interferometry (see, e.g., the Octet System by ForteBio), isothermal titration calorimetry (ITC), differential scanning calorimetry (DSC), circular dichroism (CD), stopped-flow analysis, and colorimetric or fluorescent protein melting analysis.

[0204] Additional anti-TREM1 antibodies, for example, antibodies that specifically bind to the TREM1 proteins of the present disclosure, can be identified, screened, and / or characterized for their physical / chemical properties and / or biological activity by various assays known in the art.

[0205] bispecific antibody Certain aspects of the present disclosure relate to bispecific antibodies that bind to a TREM1 protein of the present disclosure and a second antigen. Methods for making bispecific antibodies are well known in the art and described herein. In some embodiments, a bispecific antibody of the present disclosure binds to one or more amino acid residues of human TREM1 (SEQ ID NO: 1) or amino acid residues on the TREM1 protein that correspond to the amino acid residues of SEQ ID NO: 1. In other embodiments, a bispecific antibody of the present disclosure also binds to one or more amino acid residues of human DAP12 (SEQ ID NO: 560) or amino acid residues on the DAP12 protein that correspond to the amino acid residues of SEQ ID NO: 560.

[0206] In some embodiments, the bispecific antibody of the present disclosure recognizes a first antigen and a second antigen. In some embodiments, the first antigen is human TREM1 or a naturally occurring variant thereof or human DAP12 or a naturally occurring variant thereof. In some embodiments, the second antigen is selected from: (a) an antigen that promotes transport across the blood-brain barrier; (b) an antigen that promotes transport across the blood-brain barrier selected from transferrin receptor (TR), insulin receptor (HIR), insulin-like growth factor receptor (IGFR), low-density lipoprotein receptor-related proteins 1 and 2 (LPR-1 and 2), diphtheria toxin receptor, CRM197, llama single domain antibody, TMEM30(A), protein transduction domain, TAT, Syn-B, penetratin, polyarginine peptide, angiopeptide, and ANG1005; or (c) an amyloid. amyloid beta, oligomeric amyloid beta, amyloid beta plaque, amyloid precursor protein or its fragments, tau, IAPP, α-synuclein, TDP-43, FUS protein, C9orf72 (chromosome 9 open reading frame 72), c9RAN protein, prion protein, PrPSc, huntingtin, calcitonin, superoxide dismutase, ataxin, ataxin 1, ataxin 2, ataxin 3, ataxin 7, ataxin 8, ataxin 10, Lewy bodies, atrial natriuretic factor, islet amyloid polypeptide, insulin, apolipoproteinSelected from AI, serum amyloid A, medin, prolactin, transthyretin, lysozyme, β2 microglobulin, gelsolin, keratoepithelin, cystatin, immunoglobulin light chain AL, S-IBM protein, repeat-associated non-ATG (RAN) translation product, dipeptide repeat (DPR) peptide, glycine-alanine (GA) repeat peptide, glycine-proline (GP) repeat peptide, glycine-arginine (GR) repeat peptide, proline-alanine (PA) repeat peptide, ubiquitin, and proline-arginine (PR) repeat peptide. (d) a disease-causing protein selected from the group consisting of CD40, OX40, ICOS, CD28, CD137 / 4-1BB, CD27, GITR, PD-L1, CTLA-4, PD-L2, PD-1, B7-H3, B7-H4, HVEM, BTLA, KIR, GAL9, TIM3, A2AR, LAG-3, and phosphatidylserine; and (e) a protein, lipid, polysaccharide, or glycolipid expressed on one or more tumor cells, and any combination thereof.

[0207] antibody fragment Certain aspects of the present disclosure relate to antibody fragments that bind to one or more of human TREM1, naturally occurring variants of human TREM1, and disease variants of human TREM1. In some embodiments, the antibody fragment is a Fab, Fab', Fab'-SH, F(ab')2, Fv, or scFv fragment. In some embodiments, the antibody fragment is selected from the group consisting of: a) an antigen that promotes transport across the blood-brain barrier; (b) an antigen that promotes transport across the blood-brain barrier selected from transferrin receptor (TR), insulin receptor (HIR), insulin-like growth factor receptor (IGFR), low-density lipoprotein receptor-related proteins 1 and 2 (LPR-1 and 2), diphtheria toxin receptor, CRM197, llama single domain antibody, TMEM30(A), protein transduction domain, TAT, Syn-B, penetratin, polyarginine peptides, angiopeptides, and ANG1005; (c) an antigen that promotes transport across the blood-brain barrier selected from amyloid beta, oligomeric amyloid beta, amyloid beta plaques, amyloid precursor protein or fragments thereof, tau, IAPP, alpha-synuclein, TDP-43, FUS protein, C9orf72 (chromosome 9 open reading frame 72), c9RAN protein, prion protein, PrPSc, huntingtin, calcitonin, superoxide dismutase, ataxin, and atta ataxin-1, ataxin-2, ataxin-3, ataxin-7, ataxin-8, ataxin-10, Lewy bodies, atrial natriuretic factor, islet amyloid polypeptide, insulin, apolipoprotein AI, serum amyloid A, medin, prolactin, transthyretin, lysozyme, β2-microglobulin, gelsolin, keratoepithelin, cystatin, immunoglobulin light chain AL, S-IBM protein, repeat-associated non-ATG (RAN) translation products, dipeptide repeat (DPR) ) peptides, glycine-alanine (GA) repeat peptides, glycine-proline (GP) repeat peptides, glycine-arginine (GR) repeat peptides, proline-alanine (PA) repeat peptides, ubiquitin, and proline-arginine (PR) repeat peptides, and (d) ligands and / or proteins expressed on immune cells, such as CD40, OX40, ICOS, CD28, CD137 / 4-1BB, CD27,and (e) a ligand and / or protein selected from GITR, PD-L1, CTLA-4, PD-L2, PD-1, B7-H3, B7-H4, HVEM, BTLA, KIR, GAL9, TIM3, A2AR, LAG-3, and phosphatidylserine, in combination with one or more antibodies that specifically bind to a disease-causing protein selected from a protein, lipid, polysaccharide, or glycolipid expressed on one or more tumor cells, and any combination thereof.

[0208] Antibody Framework Any of the antibodies described herein further comprise a framework used as a human immunoglobulin framework. For example, in some embodiments, an antibody (e.g., an anti-TREM1 antibody) comprises an HVR as in any of the above embodiments and further comprises an acceptor human framework, e.g., a human immunoglobulin framework or a human consensus framework. The human immunoglobulin framework can be part of a human antibody, or a non-human antibody can be humanized by replacing one or more endogenous framework regions with human framework region(s). Human framework regions that can be used for humanization include, but are not limited to, framework regions selected using the "best fit" method (see, e.g., Sims et al., J. Immunol. 151:2296 (1993)), framework regions derived from the consensus sequence of human antibodies of a particular subgroup of light or heavy chain variable regions (see, e.g., Carter et al., Proc. Natl. Acad. Sci. USA, 89:4285 (1992); and Presta et al., J. Immunol., 151:2623 (1993)), human mature (somatically mutated) framework regions or human germline framework regions (see, e.g., Almagro and Fransson, Front. Biosci. 13:1619-1633 (2008)), and framework regions derived from screening FR libraries (see, e.g., Baca et al., J. Biol. Chem. 272:10678-10684 (1997) and Rosok et al., J. Biol. Chem. 271:22611-22618 (1996).

[0209] In some embodiments, the antibody comprises a light chain variable region comprising HVR-L1, HVR-L2, and HVR-L3 of this disclosure and one, two, three, or four of the light chain framework regions as set out in Table 4. In some embodiments, the antibody comprises a heavy chain variable region comprising HVR-H1, HVR-H2, and HVR-H3 of this disclosure and one, two, three, or four of the heavy chain framework regions as set out in Table 5. In some embodiments, the antibody comprises a light chain variable region comprising HVR-L1, HVR-L2, and HVR-L3 of this disclosure and one, two, three, or four of the light chain framework regions as set out in Table 4, and further comprises a heavy chain variable region comprising HVR-H1, HVR-H2, and HVR-H3 of this disclosure and one, two, three, or four of the heavy chain framework regions as set out in Table 5.

[0210] PI3K activation In some embodiments, the anti-TREM1 antibodies of the present disclosure can induce PI3K activation after binding to TREM1 protein expressed in cells.

[0211] PI3Ks are a family of related intracellular signaling kinases that can phosphorylate the 3-hydroxyl group of the inositol ring of phosphatidylinositol (PtdIns). The PI3K family is divided into three distinct classes (class I, class II, and class III) based on primary structure, regulation, and in vitro lipid substrate specificity.

[0212] Activated PI3K produces various 3-phosphoinositides, including, but not limited to, PtdIns3P, PtdIns(3,4)P2, PtdIns(3,5)P2, and PtdIns(3,4,5)P3. These 3-phosphoinositides function in the recruitment of signaling proteins to various cell membranes. These signaling proteins contain phosphoinositide-binding domains, including, but not limited to, a PX domain, a pleckstrin homology domain (PH domain), and a FYVE domain. Any method known in the art can be used to examine PI3K activation.

[0213] In some embodiments, the anti-TREM1 antibodies of the present disclosure may be useful for preventing, reducing the risk of, or treating conditions and / or diseases associated with reduced levels of PI3K activity.

[0214] Regulation of cytokine expression In some embodiments, the anti-TREM1 antibodies of the present disclosure modulate (e.g., increase or decrease) pro-inflammatory mediators in the brain after binding to TREM1 protein expressed on the cell surface. The anti-TREM1 antibodies of the present disclosure modulate the expression of cytokines (e.g., anti-inflammatory mediators) and / or modulate the expression of pro-inflammatory mediators after binding to TREM1 protein expressed in cells. Once cells die due to lack of TREM1 signaling, they induce a pro-inflammatory response.

[0215] Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, damaged cells, and irritants, such as pathogens. Classical signs of acute inflammation are pain, heat, redness, swelling, and loss of function. Inflammation is a protective attempt by the organism to remove the injurious stimulus and initiate the healing process. Inflammation can be classified as either acute or chronic. Acute inflammation is the body's initial response to harmful stimuli and is accompanied by increased migration of plasma and leukocytes (particularly granulocytes) from the blood to the injured tissue. A cascade of biochemical events propagates and matures the inflammatory response, involving the local vasculature, immune system, and various cells within the injured tissue. Chronic inflammation is prolonged inflammation leading to a progressive shift in cell types present at the site of inflammation and is characterized by the simultaneous destruction and healing of tissue resulting from the inflammatory process.

[0216] As used herein, an anti-inflammatory mediator is a protein that is directly or indirectly (e.g., via an anti-inflammatory signaling pathway) involved in the mechanism of reducing, inhibiting, or inactivating an inflammatory response. Any method known in the art can be used to identify and characterize anti-inflammatory mediators. Examples of anti-inflammatory mediators include, but are not limited to, cytokines such as IL-4, IL-10, TGF-β, IL-13, IL-35, IL-16, IFN-α, IL-1Ra, VEGF, G-CSF, and soluble receptors for TNF or IL-6.

[0217] In some embodiments, the anti-TREM1 antibodies of the present disclosure may modulate the expression of cytokines such as IL-12p70, IL-6, and IL-10. In certain embodiments, the modulation of cytokine expression occurs in macrophages, dendritic cells, monocytes, osteoclasts, dermal Langerhans cells, Kupffer cells, and / or microglial cells. Modulation of expression may include, but is not limited to, modulation of gene expression, modulation of transcriptional expression, or modulation of protein expression. Any method known in the art may be used to determine gene, transcript (e.g., mRNA), and / or protein expression. For example, Northern blot analysis may be used to determine cytokine gene expression levels, RT-PCR may be used to determine cytokine transcription levels, and Western blot analysis may be used to determine cytokine protein levels.

[0218] As used herein, a cytokine may have regulated (e.g., increased or decreased) expression when its expression in one or more cells of a subject treated with an anti-TREM1 antibody of the present disclosure is regulated compared to the expression of the same cytokine expressed in one or more cells of a corresponding subject not treated with an anti-TREM1 antibody. In some embodiments, an anti-TREM1 antibody of the present disclosure may modulate cytokine expression in one or more cells of a subject by, for example, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 100%, at least 110%, at least 115%, at least 120%, at least 125%, at least 130%, at least 135%, at least 140%, at least 145%, at least 150%, at least 160%, at least 170%, at least 180%, at least 190%, or at least 200%, compared to cytokine expression in one or more cells of a corresponding subject not treated with an anti-TREM1 antibody.In other embodiments, the anti-TREM1 antibodies of the present disclosure modulate cytokine expression in one or more cells of a subject, e.g., by at least 1.5-fold, at least 1.6-fold, at least 1.7-fold, at least 1.8-fold, at least 1.9-fold, at least 2.0-fold, at least 2.1-fold, at least 2.15-fold, at least 2.2-fold, at least 2.25-fold, at least 2.3-fold, at least 2.35-fold, at least 2.4-fold, at least 2.45-fold, at least 2.5-fold, at least 2.55-fold, at least 3.0-fold, at least 3.5-fold, at least 4.0-fold, at least 4.5-fold, at least 5.0-fold, at least 5.5-fold, at least 6.0-fold, at least 6.5-fold, at least 7.0-fold, at least 7.5-fold, at least 8.0-fold, at least 8.5-fold, at least 9.0-fold, at least 9.5-fold, or at least 10-fold, compared to cytokine expression in one or more cells of a corresponding subject not treated with the anti-TREM1 antibody.

[0219] In some embodiments, the anti-TREM1 antibodies of the present disclosure may be useful for preventing, reducing the risk of, or treating conditions and / or diseases associated with abnormal levels of one or more anti-inflammatory mediators.

[0220] Regulation of the expression of pro-inflammatory mediators In some embodiments, the anti-TREM1 antibodies of the present disclosure may modulate (eg, increase or decrease) the expression of pro-inflammatory mediators after binding to a TREM1 protein expressed in a cell.

[0221] As used herein, a pro-inflammatory mediator is a protein that is either directly or indirectly (e.g., via an inflammatory signaling pathway) involved in mechanisms that induce, activate, promote, or otherwise augment an inflammatory response. Any method known in the art for identifying and characterizing pro-inflammatory mediators can be used. Examples of pro-inflammatory mediators include, but are not limited to, cytokines such as FN-□, IL-1□, IL-1β, TNF-α, IL-6, IL-8, CRP, IL-20 family members, IL-33, LIF, IFN-γ, OSM, CNTF, GM-CSF, IL-11, IL-12, IL-17, IL-18, IL-23, CXCL10, and MCP-1.

[0222] In some embodiments, anti-TREM1 antibodies of the present disclosure may modulate the functional expression and / or secretion of pro-inflammatory mediators such as IFN-α4, IFN-β, IL-1β, TNF-α, IL-10, IL-6, IL-8, CRP, members of the TGF-β chemokine protein family, IL-20 family members, IL-33, LIF, IFN-γ, OSM, CNTF, GM-CSF, IL-11, IL-12, IL-23, MCP-1, CXCL10, VEGF, IL-17, IL-18, and CRP. In certain embodiments, modulation of pro-inflammatory mediator expression occurs in macrophages, dendritic cells, monocytes, osteoclasts, dermal Langerhans cells, Kupffer cells, and / or microglial cells. Modulation of expression may include, but is not limited to, modulation of gene expression, modulation of transcriptional expression, or modulation of protein expression. Any method known in the art can be used to determine gene, transcript (e.g., mRNA) and / or protein expression. For example, Northern blot analysis can be used to determine pro-inflammatory mediator gene expression levels, RT-PCR can be used to determine pro-inflammatory mediator transcript levels, and Western blot analysis can be used to determine pro-inflammatory mediator protein levels.

[0223] In certain embodiments, pro-inflammatory mediators include inflammatory cytokines. Thus, in certain embodiments, anti-TREM1 antibodies of the present disclosure may modulate the secretion of one or more inflammatory cytokines. Examples of inflammatory cytokines whose secretion may be reduced by anti-TREM1 antibodies of the present disclosure include, but are not limited to, IFN-α4, IFN-β, IL-1β, TNF-α, IL-10, IL-6, IL-8, CRP, TGF-β, members of the chemokine protein family, IL-20 family members, IL-33, LIF, IFN-γ, OSM, CNTF, GM-CSF, IL-11, IL-12, IL-23, MCP-1, CXCL10, VEGF, IL-17, IL-18, CRP, and MCP-1.

[0224] In certain embodiments, pro-inflammatory mediators include inflammatory receptors. Thus, in certain embodiments, anti-TREM1 antibodies of the present disclosure may modulate the expression of one or more inflammatory receptors. Examples of inflammatory receptors whose expression may be reduced by anti-TREM1 antibodies of the present disclosure include, but are not limited to, CD86.

[0225] As used herein, a pro-inflammatory mediator may have regulated expression if its expression in one or more cells of a subject treated with an agonistic anti-TREM1 antibody of the present disclosure is regulated (e.g., increased or decreased) compared to the expression of the same pro-inflammatory mediator expressed in one or more cells of a corresponding subject not treated with an agonistic anti-TREM1 antibody. In some embodiments, an agonist anti-TREM1 antibody of the present disclosure may modulate pro-inflammatory mediator expression in one or more cells of a subject by, for example, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 100%, at least 110%, at least 115%, at least 120%, at least 125%, at least 130%, at least 135%, at least 140%, at least 145%, at least 150%, at least 160%, at least 170%, at least 180%, at least 190%, or at least 200%, compared to pro-inflammatory mediator expression in one or more cells of a corresponding subject not treated with the agonist anti-TREM1 antibody.In other embodiments, the agonist anti-TREM1 antibody increases pro-inflammatory mediator expression in one or more cells of a subject by, for example, at least 1.5-fold, at least 1.6-fold, at least 1.7-fold, at least 1.8-fold, at least 1.9-fold, at least 2.0-fold, at least 2.1-fold, at least 2.15-fold, at least 2.2-fold, at least 2.3-fold, at least 2.4-fold, at least 2.5-fold, at least 2.6-fold, at least 2.7-fold, at least 2.8-fold, at least 2.9-fold, at least 3.0-fold, at least 3.10-fold, at least 3.15-fold, at least 3.25-fold, at least 3.30-fold, at least 3.40-fold, at least 3.50-fold, at least 3.60-fold, at least 3.70-fold, at least 3.80-fold, at least 3.90-fold, at least 3.90-fold, at least 3.15-fold, at least 3.16-fold, at least 3.18-fold, at least 3.19-fold, at least 3.21-fold, at least 3.22-fold, at least 3.23-fold, at least 3.24-fold, at least 3.25-fold, at least 3.26-fold, at least 3.27-fold, at least 3.28-fold, at least 3.29-fold, at least 3.30-fold, at least 3.31-fold, at least 3.32-fold, at least 3.33-fold, at least 3.34-fold, at least 3.35-fold, at least 3.36-fold, at least 3.37-fold, at least The modulation may be at least 0.25-fold, at least 2.3-fold, at least 2.35-fold, at least 2.4-fold, at least 2.45-fold, at least 2.5-fold, at least 2.55-fold, at least 3.0-fold, at least 3.5-fold, at least 4.0-fold, at least 4.5-fold, at least 5.0-fold, at least 5.5-fold, at least 6.0-fold, at least 6.5-fold, at least 7.0-fold, at least 7.5-fold, at least 8.0-fold, at least 8.5-fold, at least 9.0-fold, at least 9.5-fold, or at least 10-fold.

[0226] In some embodiments, the anti-TREM1 antibodies of the present disclosure may be useful for preventing, reducing the risk of, or treating conditions and / or diseases associated with abnormal levels of one or more pro-inflammatory mediators.

[0227] ERK phosphorylation In some embodiments, the anti-TREM1 antibodies of the present disclosure can induce extracellular signal-regulated kinase (ERK) phosphorylation after binding to a TREM1 protein expressed in a cell.

[0228] Extracellular signal-regulated kinase (ERK) is a widely expressed protein kinase intracellular signaling kinase involved in regulating, for example, meiosis, mitosis, and postmitotic functions in differentiated cells. Various stimuli, including growth factors, cytokines, viral infections, ligands of heterotrimeric G protein-coupled receptors, transforming agents, and carcinogens, activate the ERK pathway. Phosphorylation of ERK leads to activation of its kinase activity.

[0229] In some embodiments, the anti-TREM1 antibodies of the present disclosure may be useful in preventing, reducing the risk of, or treating conditions and / or diseases associated with reduced levels of ERK phosphorylation.

[0230] Syk phosphorylation In some embodiments, the anti-TREM1 antibodies of the present disclosure can induce spleen tyrosine kinase (Syk) phosphorylation after binding to a TREM1 protein expressed in a cell.

[0231] Spleen tyrosine kinase (Syk) is an intracellular signaling molecule that functions downstream of TREM1 by phosphorylating several substrates, thereby promoting the formation of signaling complexes that lead to cell activation and inflammatory processes.

[0232] In some embodiments, the anti-TREM1 antibodies of the present disclosure may be useful in preventing, reducing the risk of, or treating conditions and / or diseases associated with reduced levels of Syk phosphorylation.

[0233] TREM1 autophosphorylation In some embodiments, the anti-TREM1 antibodies of the present disclosure can induce TREM1 autophosphorylation after binding to a TREM1 protein expressed in a cell.

[0234] In some embodiments, the anti-TREM1 antibodies of the present disclosure may be useful in preventing, reducing the risk of, or treating conditions and / or diseases associated with reduced levels of TREM1 phosphorylation.

[0235] DAP12 binding and phosphorylation In some embodiments, the anti-TREM1 antibodies of the present disclosure can induce binding of TREM1 to DAP12. In other embodiments, the anti-TREM1 antibodies of the present disclosure can induce DAP12 phosphorylation after binding to a TREM1 protein expressed in a cell. In other embodiments, TREM1-mediated DAP12 phosphorylation is induced by one or more SRC family tyrosine kinases. Examples of Src family tyrosine kinases include, but are not limited to, Src, Syk, Yes, Fyn, Fgr, Lck, Hck, Blk, Lyn, and Frk.

[0236] DAP12 is variously referred to as TYRO protein tyrosine kinase binding protein, TYROBP, KARAP, and PLOSL. DAP12 is a transmembrane signaling protein containing an immunoreceptor tyrosine-based activation motif (ITAM) in its cytoplasmic domain. In certain embodiments, anti-TREM1 and / or anti-DAP12 antibodies can induce DAP12 phosphorylation at its ITAM motif. Any method known in the art can be used to examine protein phosphorylation, such as DAP12 phosphorylation.

[0237] In some embodiments, DAP12 is phosphorylated by SRC family kinases, resulting in the recruitment and activation of Syk kinase, ZAP70 kinase, or both, to the DAP12 / TREM1 complex. Accordingly, in certain embodiments, the anti-TREM1 antibodies of the present disclosure may recruit Syk, ZAP70, or both, to the DAP12 / TREM1 complex. Without being bound by theory, it is believed that the anti-TREM1 antibodies of the present disclosure are useful for preventing, reducing the risk of, or treating conditions and / or diseases associated with decreased levels of DAP12 activity, DAP12 phosphorylation, or recruitment of Syk, ZAP70, or both, to the DAP12 / TREM1 complex.

[0238] Regulation of CC chemokine receptor 7 expression In some embodiments, the anti-TREM1 antibodies of the present disclosure may modulate (e.g., increase or decrease) CC chemokine receptor 7 (CCR7) expression after binding to a TREM1 protein expressed in a cell. Modulation of expression may include, but is not limited to, modulation of gene expression, modulation of transcriptional expression, or modulation of protein expression. Any method known in the art may be used to determine gene, transcript (e.g., mRNA), and / or protein expression. For example, Northern blot analysis may be used to determine anti-inflammatory mediator gene expression levels, RT-PCR may be used to determine anti-inflammatory mediator transcription levels, and Western blot analysis may be used to determine anti-inflammatory mediator protein levels.

[0239] CC chemokine receptor 7 (CCR7) is a member of the G protein-coupled receptor family. CCR7 is expressed in various lymphoid tissues and can activate B cells and T cells. In some embodiments, CCR7 can regulate the migration of memory T cells to secondary lymphoid organs, such as lymph nodes. In other embodiments, CCR7 can stimulate dendritic cell maturation. CCR7 is a receptor protein that can bind to the chemokine (CC motif) ligands CCL19 / ELC and CCL21.

[0240] As used herein, CCR7 may have regulated (e.g., increased or decreased) expression when its expression in one or more cells of a subject treated with an anti-TREM1 antibody of the present disclosure is regulated compared to the expression of CCR7 expressed in one or more cells of a corresponding subject not treated with an anti-TREM1 antibody. In some embodiments, an anti-TREM1 antibody of the present disclosure may modulate CCR7 expression in one or more cells of a subject by, for example, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 100%, at least 110%, at least 115%, at least 120%, at least 125%, at least 130%, at least 135%, at least 140%, at least 145%, at least 150%, at least 160%, at least 170%, at least 180%, at least 190%, or at least 200%, compared to CCR7 expression in one or more cells of a corresponding subject not treated with an anti-TREM1 antibody. In other embodiments, the anti-TREM1 antibodies of the present disclosure modulate CCR7 expression in one or more cells of a subject, e.g., by at least 1.5-fold, at least 1.6-fold, at least 1.7-fold, at least 1.8-fold, at least 1.9-fold, at least 2.0-fold, at least 2.1-fold, at least 2.15-fold, at least 2.2-fold, at least 2.25-fold, at least 2.3-fold, at least 2.35-fold, at least 2.4-fold, at least 2.45-fold, at least 2.5-fold, at least 2.55-fold, at least 3.0-fold, at least 3.5-fold, at least 4.0-fold, at least 4.5-fold, at least 5.0-fold, at least 5.5-fold, at least 6.0-fold, at least 6.5-fold, at least 7.0-fold, at least 7.5-fold, at least 8.0-fold, at least 8.5-fold, at least 9.0-fold, at least 9.5-fold, or at least 10-fold, compared to CCR7 expression in one or more cells of a corresponding subject not treated with the anti-TREM1 antibody.

[0241] In some embodiments, modulation of CCR7 expression occurs in macrophages, dendritic cells, and / or microglial cells. Increased expression of CCR7 can induce microglial cell chemotaxis toward cells expressing the chemokines CCL19 and CCL21. Thus, in certain embodiments, anti-TREM1 antibodies of the present disclosure can induce microglial cell chemotaxis toward CCL19- and CCL21-expressing cells.

[0242] In some embodiments, the anti-TREM1 antibodies of the present disclosure may be useful for preventing, reducing the risk of, or treating conditions and / or diseases associated with abnormal levels of CCR7, including dementia, frontotemporal dementia, Alzheimer's disease, Nasu-Hakola disease, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, and tauopathy.

[0243] Enhancement or normalization of the ability of bone marrow-derived dendritic cells to stimulate antigen-specific T cells or to regulate their function In some embodiments, the anti-TREM1 antibodies of the present disclosure may enhance and / or normalize the ability of bone marrow-derived dendritic cells to stimulate or regulate the function of antigen-specific T cells, including CD8+ T cells, CD4+ T cells and / or regulatory T cells, after binding to TREM1 protein expressed in the cells.

[0244] In some embodiments, the agonistic anti-TREM1 antibodies of the present disclosure improve the ability of bone marrow-derived dendritic cells to prime or modulate the function of one or more antigen-specific T cells in a subject, e.g., by at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, or at least 50% of the total dendritic cells in a subject that has not been treated with an agonistic anti-TREM1 antibody. may be enhanced and / or normalized by at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 100%, at least 110%, at least 115%, at least 120%, at least 125%, at least 130%, at least 135%, at least 140%, at least 145%, at least 150%, at least 160%, at least 170%, at least 180%, at least 190% or at least 200%. In other embodiments, the agonist anti-TREM1 antibody increases the ability of bone marrow-derived dendritic cells to prime or modulate the function of antigen-specific T cells in a subject, e.g., by at least at least 1.5-fold, at least 1.6-fold, at least 1.7-fold, at least 1.8-fold, at least 1.9-fold, at least 2.0-fold, at least 2.1-fold, at least 2.15-fold, ...5-fold, at least The expression level may be enhanced and / or normalized by at least 2.2-fold, at least 2.25-fold, at least 2.3-fold, at least 2.35-fold, at least 2.4-fold, at least 2.45-fold, at least 2.5-fold, at least 2.55-fold, at least 3.0-fold, at least 3.5-fold, at least 4.0-fold, at least 4.5-fold, at least 5.0-fold, at least 5.5-fold, at least 6.0-fold, at least 6.5-fold, at least 7.0-fold, at least 7.5-fold, at least 8.0-fold, at least 8.5-fold, at least 9.0-fold, at least 9.5-fold, or at least 10-fold.

[0245] In some embodiments, the anti-TREM1 antibodies of the present disclosure may be useful for preventing, reducing the risk of, or treating conditions and / or diseases associated with a reduced or dysregulated ability of bone marrow-derived dendritic cells to prime or regulate the function of antigen-specific T cells.

[0246] Osteoclast production In some embodiments, the anti-TREM1 antibodies of the present disclosure may induce osteoclast production and / or increase the rate of osteoclast formation after binding to TREM1 protein expressed in cells.

[0247] As used herein, osteoclasts are a type of bone cell that can remove bone tissue by removing its mineralized matrix and breaking down organic bone (e.g., bone resorption). Osteoclasts can be formed by the fusion of cells of a monocyte-macrophage cell line. In some embodiments, osteoclasts can be characterized by high expression of tartrate-resistant acid phosphatase (TRAP) and cathepsin K.

[0248] As used herein, the rate of osteoclast formation can be increased if the rate of osteoclast formation in a subject treated with an agonistic anti-TREM1 antibody of the present disclosure is greater than the rate of osteoclast formation in a corresponding subject not treated with an agonistic anti-TREM1 antibody. In some embodiments, the agonistic anti-TREM1 antibodies of the present disclosure may increase the rate of osteoclast formation in a subject by, for example, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 100%, at least 110%, at least 115%, at least 120%, at least 125%, at least 130%, at least 135%, at least 140%, at least 145%, at least 150%, at least 160%, at least 170%, at least 180%, at least 190%, or at least 200% compared to the rate of osteoclast formation in a corresponding subject not treated with the agonistic anti-TREM1 antibody. In other embodiments, the agonist anti-TREM1 antibodies of the present disclosure may increase the rate of osteoclast formation in a subject by, for example, at least 1.5-fold, at least 1.6-fold, at least 1.7-fold, at least 1.8-fold, at least 1.9-fold, at least 2.0-fold, at least 2.1-fold, at least 2.15-fold, at least 2.2-fold, at least 2.25-fold, at least 2.3-fold, at least 2.35-fold, at least 2.4-fold, at least 2.45-fold, at least 2.5-fold, at least 2.55-fold, at least 3.0-fold, at least 3.5-fold, at least 4.0-fold, at least 4.5-fold, at least 5.0-fold, at least 5.5-fold, at least 6.0-fold, at least 6.5-fold, at least 7.0-fold, at least 7.5-fold, at least 8.0-fold, at least 8.5-fold, at least 9.0-fold, at least 9.5-fold, or at least 10-fold, compared to the rate of osteoclast formation in a corresponding subject not treated with the agonist anti-TREM1 antibody.

[0249] As used herein, the rate of osteoclast formation can be reduced if the rate of osteoclast formation in a subject treated with an antagonistic anti-TREM1 antibody of the present disclosure is less than the rate of osteoclast formation in a corresponding subject not treated with an antagonistic anti-TREM1 antibody. In some embodiments, the antagonist anti-TREM1 antibodies of the present disclosure may reduce the rate of osteoclast formation in a subject by, for example, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 100%, at least 110%, at least 115%, at least 120%, at least 125%, at least 130%, at least 135%, at least 140%, at least 145%, at least 150%, at least 160%, at least 170%, at least 180%, at least 190%, or at least 200% compared to the rate of osteoclast formation in a corresponding subject not treated with the antagonist anti-TREM1 antibody. In other embodiments, the antagonist anti-TREM1 antibodies of the disclosure increase the rate of osteoclast formation in a subject by, for example, at least 1.5-fold, at least 1.6-fold, at least 1.7-fold, at least 1.8-fold, at least 1.9-fold, at least 2.0-fold, at least 2.1-fold, at least 2.15-fold, at least 2.2-fold, at least 2.25-fold, at least 2.3-fold, at least 2.4-fold, at least 2.5-fold, at least 2.6-fold, at least 2.7-fold, at least 2.8-fold, at least 2.9-fold, at least 3.0-fold, at least 3.10-fold, at least 3.11-fold, at least 3.12-fold, at least 3.13-fold, at least 3.14-fold, at least 3.15-fold, at least 3.16-fold, at least 3.17-fold, at least 3.18-fold, at least 3.19-fold, at least 3.20-fold, at least 3.21-fold, at least 3.22-fold, at least 3.23-fold, at least 3.24-fold, at least 3.25-fold, at least 3.26-fold, at least 3.27-fold, at least 3.28-fold, at least 3.29-fold, at least 3.30-fold, at least 3.31-fold, at least 3.32-fold, at least 3.33-fold, at least 3.34-fold, at least 3.35-fold, at least 3.36-fold, at least 3.37-fold, at least 3.38-fold, at least 3.39-fold, at least 3.40-fold, at least 3.4 The reduction may be at least 0.3 fold, at least 2.35 fold, at least 2.4 fold, at least 2.45 fold, at least 2.5 fold, at least 2.55 fold, at least 3.0 fold, at least 3.5 fold, at least 4.0 fold, at least 4.5 fold, at least 5.0 fold, at least 5.5 fold, at least 6.0 fold, at least 6.5 fold, at least 7.0 fold, at least 7.5 fold, at least 8.0 fold, at least 8.5 fold, at least 9.0 fold, at least 9.5 fold or at least 10 fold.

[0250] In some embodiments, the anti-TREM1 antibodies of the present disclosure may be useful for preventing, reducing the risk of, or treating conditions and / or diseases associated with abnormal bone formation and maintenance, including osteoporosis associated with a pathological decrease in bone density and osteoporotic diseases associated with a pathological increase in bone density.

[0251] Proliferation, survival and functionality of cells expressing TREM1 In some embodiments, the anti-TREM1 antibodies of the present disclosure may increase the proliferation, survival and / or function of dendritic cells, macrophages, monocytes, osteoclasts, dermal Langerhans cells, Kupffer cells and microglial cells (microglia) after binding to TREM1 protein expressed in the cells.

[0252] Microglial cells are a type of glial cell, the resident macrophage of the brain and spinal cord, and therefore act as the first and primary form of active immune defense in the central nervous system (CNS). Microglial cells account for 20% of the total glial cell population in the brain. Microglial cells constantly clear the CNS of plaques, damaged neurons, and infectious pathogens. The brain and spinal cord are considered "immune-privileged" organs in that they are separated from the rest of the body by a series of endothelial cells known as the blood-brain barrier, which prevents most infectious diseases from reaching vulnerable neural tissue. When infectious pathogens are introduced into the brain directly or across the blood-brain barrier, microglial cells must respond rapidly to reduce inflammation and destroy the infectious pathogen before it can damage sensitive neural tissue. Due to the lack of access to antibodies from the rest of the body (a few antibodies are small enough to cross the blood-brain barrier), microglia must be able to recognize foreign substances, engulf them, and act as antigen-presenting cells to activate T cells. Because this process must occur rapidly to prevent potentially fatal damage, microglial cells are extremely sensitive to even fairly small pathological changes in the CNS. They achieve this sensitivity in part by possessing unique potassium channels that respond to fairly small changes in extracellular potassium.

[0253] As used herein, macrophages of the present disclosure include, but are not limited to, M1 macrophages, activated M1 macrophages, and M2 macrophages. As used herein, microglial cells of the present disclosure include, but are not limited to, M1 microglial cells, activated M1 microglial cells, and M2 microglial cells. In some embodiments, anti-TREM1 antibodies of the present disclosure may be useful for reducing the risk of or treating conditions and / or diseases associated with reduced immune cell proliferation or survival.

[0254] In some embodiments, the anti-TREM1 antibodies of the present disclosure may increase the expression of CD83 and / or CD86 on dendritic cells, monocytes and / or macrophages.

[0255] As used herein, the rate of proliferation, survival and / or function of macrophages, dendritic cells, monocytes and / or microglia may include increased expression when the rate of proliferation, survival and / or function of dendritic cells, macrophages, monocytes, osteoclasts, dermal Langerhans cells, Kupffer cells and / or microglia in a subject treated with an anti-TREM1 antibody of the present disclosure is greater than the rate of proliferation, survival and / or function of dendritic cells, macrophages, monocytes, osteoclasts, dermal Langerhans cells, Kupffer cells and / or microglia in a corresponding subject not treated with an anti-TREM1 antibody. In some embodiments, the anti-TREM1 antibodies of the disclosure reduce or eliminate the proliferation, survival, and / or function of dendritic cells, macrophages, monocytes, osteoclasts, dermal Langerhans cells, Kupffer cells, and / or microglia in a subject, e.g., by at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, or even more, compared to the proliferation, survival, and / or function of dendritic cells, macrophages, monocytes, osteoclasts, dermal Langerhans cells, Kupffer cells, and / or microglia in a corresponding subject not treated with an anti-TREM1 antibody. It may increase by at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 100%, at least 110%, at least 115%, at least 120%, at least 125%, at least 130%, at least 135%, at least 140%, at least 145%, at least 150%, at least 160%, at least 170%, at least 180%, at least 190% or at least 200%.In other embodiments, the anti-TREM1 antibodies of the disclosure increase the rate of proliferation, survival and / or function of dendritic cells, macrophages, monocytes, osteoclasts, dermal Langerhans cells, Kupffer cells and / or microglia in a subject, e.g., by at least 1.5-fold, at least 1.6-fold, at least 1.7-fold, at least 1.8-fold, at least 1.9-fold, at least 2-fold, or at least 3-fold increase in proliferation, survival and / or function of dendritic cells, macrophages, monocytes, osteoclasts, dermal Langerhans cells, Kupffer cells and / or microglia in a corresponding subject not treated with an anti-TREM1 antibody. The increase may be at least 2.0-fold, at least 2.1-fold, at least 2.15-fold, at least 2.2-fold, at least 2.25-fold, at least 2.3-fold, at least 2.35-fold, at least 2.4-fold, at least 2.45-fold, at least 2.5-fold, at least 2.55-fold, at least 3.0-fold, at least 3.5-fold, at least 4.0-fold, at least 4.5-fold, at least 5.0-fold, at least 5.5-fold, at least 6.0-fold, at least 6.5-fold, at least 7.0-fold, at least 7.5-fold, at least 8.0-fold, at least 8.5-fold, at least 9.0-fold, at least 9.5-fold or at least 10-fold.

[0256] In some embodiments, the anti-TREM1 antibodies of the present disclosure may be useful for preventing, reducing the risk of, or treating conditions and / or diseases associated with impaired function of dendritic cells, macrophages, monocytes, osteoclasts, dermal Langerhans cells, Kupffer cells, and / or microglia.

[0257] Clearance and phagocytosis In some embodiments, the anti-TREM1 antibodies of the present disclosure, after binding to a TREM1 protein expressed in a cell, may induce clearance and / or phagocytosis of one or more of apoptotic neurons, nervous system neural tissue debris, non-neuronal nervous system tissue debris, bacteria, other foreign bodies, disease-causing proteins, disease-causing peptides, disease-causing nucleic acids, or tumor cells. In certain embodiments, disease-causing proteins include, but are not limited to, amyloid beta or fragments thereof, tau, IAPP, alpha-synuclein, TDP-43, FUS protein, prion protein, PrPSc, huntingtin, calcitonin, superoxide dismutase, ataxin, Lewy bodies, atrial natriuretic factor, islet amyloid polypeptide, insulin, apolipoprotein AI, serum amyloid A, medin, prolactin, transthyretin, lysozyme, beta2-microglobulin, gelsolin, keratoepithelin, cystatin, immunoglobulin light chain AL, S-IBM protein, and repeat-associated non-ATG (RAN) translation products containing dipeptide repeats (DPR peptides) composed of glycine-alanine (GA), glycine-proline (GP), glycine-arginine (GR), proline-alanine (PA), or proline-arginine (PR). In certain embodiments, disease-causing nucleic acids include, but are not limited to, antisense GGCCCC (G2C4) repeat expanded RNA.

[0258] In some embodiments, the anti-TREM1 antibodies of the present disclosure may induce one or more types of clearance, including, but not limited to, apoptotic neuron clearance, neural tissue debris clearance, non-neural tissue debris clearance, bacterial or other foreign body clearance, disease-causing protein clearance, disease-causing peptide clearance, disease-causing nucleic acid clearance, and tumor cell clearance.

[0259] In some embodiments, the anti-TREM1 antibodies of the present disclosure may induce phagocytosis of one or more of apoptotic neurons, neural tissue debris, non-neural tissue debris, bacteria, other foreign bodies, disease-causing proteins, disease-causing peptides, disease-causing nucleic acids, and / or tumor cells.

[0260] In some embodiments, the anti-TREM1 antibodies of the present disclosure may increase phagocytosis by macrophages, dendritic cells, monocytes, and / or microglia under conditions of reduced levels of macrophage colony-stimulating factor (MCSF). Alternatively, in some embodiments, the anti-TREM1 antibodies of the present disclosure may increase phagocytosis by macrophages, dendritic cells, monocytes, and / or microglia in the presence of normal levels of macrophage colony-stimulating factor (MCSF).

[0261] In some embodiments, the anti-TREM1 antibodies of the present disclosure may be useful for preventing, reducing the risk of, or treating conditions and / or diseases associated with the clearance and / or phagocytosis of apoptotic neurons, nervous system neural tissue debris, non-neuronal nervous system tissue debris, bacteria, other foreign bodies, disease-causing proteins, disease-causing peptides, disease-causing nucleic acids, or tumor cells.

[0262] TREM1-dependent gene expression In some embodiments, agonist anti-TREM1 antibodies of the present disclosure may increase the activity and / or expression of TREM1-dependent genes, such as one or more transcription factors of the nuclear factor of activated T cells (NFAT) family of transcription factors. Alternatively, antagonist anti-TREM1 antibodies of the present disclosure may inhibit the activity and / or expression of TREM1-dependent genes, such as one or more transcription factors of the NFAT family of transcription factors.

[0263] In some embodiments, the anti-TREM1 antibodies of the present disclosure may be useful for preventing, reducing the risk of, or treating conditions and / or diseases associated with reduced levels of TREM1-dependent genes.

[0264] In some embodiments, the anti-TREM1 antibodies of the disclosure are used to treat dementia, frontotemporal dementia, Alzheimer's disease, vascular dementia, mixed dementia, Creutzfeldt-Jakob disease, normal pressure hydrocephalus, amyotrophic lateral sclerosis, Huntington's disease, tauopathy, Nasu-Hakola disease, stroke, acute trauma, chronic trauma, cognitive deficits, memory loss, lupus, acute and chronic colitis, rheumatoid arthritis, wound healing, Crohn's disease, inflammatory bowel disease, ulcerative colitis, obesity, malaria, essential tremor, central nervous system disorders, and the like. Systemic lupus, Behçet's disease, Parkinson's disease, dementia with Lewy bodies, multiple system atrophy, Shy-Drager syndrome, progressive supranuclear palsy, corticobasal ganglionic degeneration, acute disseminated encephalomyelitis, granulomatous disorders, sarcoidosis, diseases of aging, stroke, spinal cord injury, traumatic brain injury, age-related macular degeneration, glaucoma, retinitis pigmentosa, retinal degeneration, respiratory tract infections, sepsis, eye infections, systemic infections, lupus, arthritis, multiple sclerosis, low bone density, osteoporosis, bone formation, osteopetrosis , Paget's disease of bone, cancer, bladder cancer, brain cancer, e.g., glioma or glioblastoma, breast cancer, cervical cancer, colon cancer, rectal cancer, endometrial cancer, kidney cancer, renal cell carcinoma, renal pelvis cancer, leukemia, lung cancer, e.g., non-small cell lung cancer, melanoma, non-Hodgkin's lymphoma, pancreatic cancer, prostate cancer, ovarian cancer, fibrosarcoma, acute lymphocytic leukemia (ALL), acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL), chronic myeloid leukemia (CML), multiple myeloma, polycythemia vera, essential thrombocytosis, primary or may be beneficial for preventing, reducing the risk of, or treating conditions and / or diseases including idiopathic myelofibrosis, primary or idiopathic myelosclerosis, bone marrow derived tumors, TREM1 expressing tumors, thyroid cancer, infectious diseases, CNS herpes, parasitic infections, Trypanosoma infections, cruzi infections, Pseudomonas aeruginosa infections, Leishmania donovani infections, group B Streptococcus infections, Campylobacter jejuni infections, Neisseria meningitidis infections, HIV type 1, and Haemophilus influenzae.

[0265] In some embodiments, methods of treating a disease or condition according to the present invention include administering to an individual in need thereof a therapeutically effective amount of an agent that does not inhibit the interaction between TREM1 and one or more TREM1 ligands and / or enhances one or more activities of at least one TREM1 ligand.

[0266] Other aspects of the present disclosure include the use of therapeutic agents for dementia, frontotemporal dementia, Alzheimer's disease, vascular dementia, mixed dementia, Creutzfeldt-Jakob disease, normal pressure hydrocephalus, amyotrophic lateral sclerosis, Huntington's chorea, tauopathy, Nasu-Hakola disease, stroke, acute trauma, chronic trauma, cognitive deficits, memory loss, lupus, acute and chronic colitis, rheumatoid arthritis, wound healing, Crohn's disease, inflammatory bowel disease, ulcerative colitis, obesity, malaria, essential tremor, central nervous system lupus, Behcet's disease, Parkinson's disease , dementia with Lewy bodies, multiple system atrophy, Shy-Drager syndrome, progressive supranuclear palsy, corticobasal ganglionic degeneration, acute disseminated encephalomyelitis, granulomatous disorders, sarcoidosis, diseases of aging, stroke, spinal cord injury, traumatic brain injury, age-related macular degeneration, glaucoma, retinitis pigmentosa, retinal degeneration, respiratory tract infections, sepsis, eye infections, systemic infections, lupus, arthritis, multiple sclerosis, low bone density, osteoporosis, bone formation, osteopetrosis, Paget's bone disease, cancer, bladder cancer, brain cancer, e.g., low-grade glial cell carcinoma tumors such as glioma or glioblastoma, breast cancer, cervical cancer, colon cancer, rectal cancer, endometrial cancer, kidney cancer, renal cell carcinoma, renal pelvis cancer, leukemia, lung cancer, e.g., non-small cell lung cancer, melanoma, non-Hodgkin's lymphoma, pancreatic cancer, prostate cancer, ovarian cancer, fibrosarcoma, acute lymphocytic leukemia (ALL), acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL), chronic myelogenous leukemia (CML), multiple myeloma, polycythemia vera, essential thrombocytosis, primary or idiopathic myelofibrosis, primary or idiopathic myelosclerosis, bone marrow The present invention relates to an agent that does not inhibit the interaction between TREM1 and one or more CD33 ligands for use in preventing, reducing the risk of, or treating a disease, disorder, or injury selected from: a TREM1-derived tumor, a TREM1-expressing tumor, a thyroid cancer, an infectious disease, a CNS herpes, a parasitic infection, a Trypanosoma infection, a cruzi infection, a Pseudomonas aeruginosa infection, a Leishmania donovani infection, a group B Streptococcus infection, a Campylobacter jejuni infection, a meningococcal infection, HIV type 1, and a Haemophilus influenzae infection.

[0267] Antibody preparation Anti-TREM1 antibodies of the present disclosure may include polyclonal antibodies, monoclonal antibodies, humanized and chimeric antibodies, human antibodies, antibody fragments (e.g., Fab, Fab'-SH, Fv, scFv, and F(ab')2), bispecific and multispecific antibodies, multivalent antibodies, library-derived antibodies, antibodies with modified effector functions, fusion proteins containing antibody moieties, and any other modified configuration of immunoglobulin molecules comprising an antigen recognition site, such as an epitope, having amino acid residues of a TREM1 protein of the present disclosure, including glycosylation variants of antibodies, amino acid sequence variants of antibodies, and covalently modified antibodies. Anti-TREM1 antibodies may be human, murine, rat, or of any other origin (including chimeric or humanized antibodies).

[0268] (1) Polyclonal antibodies Polyclonal antibodies, such as anti-TREM1 polyclonal antibodies, are generally raised in animals by multiple subcutaneous (sc) or intraperitoneal (ip) injections of the relevant antigen and an adjuvant. Bifunctional or derivatizing agents, such as maleimidobenzoyl sulfosuccinimide ester (for conjugation through cysteine ​​residues), N-hydroxysuccinimide (for conjugation through lysine residues), glutaraldehyde, succinic anhydride, SOCl2, or R 1 N=C=NR, where R and R 1 It may be useful to conjugate the relevant antigen (e.g., a purified or recombinant TREM1 protein of the present disclosure) to a protein that is immunogenic in the species to be immunized, such as keyhole limpet hemocyanin (KLH), serum albumin, bovine thyroglobulin, or soybean trypsin inhibitor, using an adjuvant such as PEG / PEG-100 (where PEG / PEG-100 and PEG-100 are independently lower alkyl groups). Examples of adjuvants that may be used include Freund's complete adjuvant and MPL-TDM adjuvant (monophosphoryl lipid A, synthetic trehalose dicorynomycolate). The immunization protocol may be selected by one skilled in the art without undue experimentation.

[0269] Animals are immunized against the desired antigen, immunogenic conjugate, or derivative by combining, for example, 100 μg (for rabbits) or 5 μg (for mice) of protein or conjugate with 3 volumes of Freund's complete adjuvant and injecting the solution intradermally at multiple sites. One month later, the animals are boosted with 1 / 5-1 / 10 the original amount of peptide or conjugate in Freund's complete adjuvant by subcutaneous injection at multiple sites. 7-14 days later, the animals are bled and the serum is assayed for antibody titer. Animals are boosted until the titer plateaus. Conjugates can also be produced in recombinant cell culture as protein fusions. Aggregating agents such as alum are also suitable for enhancing the immune response.

[0270] (2) Monoclonal antibodies Monoclonal antibodies, such as anti-TREM1 monoclonal antibodies, are obtained from a population of substantially homogeneous antibodies, i.e., the population of individual antibodies are identical except for possible naturally occurring mutations and / or post-translational modifications (e.g., isomerization, amidation) that may be present in minor amounts. Thus, the modifier "monoclonal" indicates the character of the antibody as not being a mixture of discrete antibodies.

[0271] For example, anti-TREM1 monoclonal antibodies may be made using the hybridoma method first described by Kohler et al., Nature, 256:495 (1975), or may be made by recombinant DNA methods (U.S. Patent No. 4,816,567).

[0272] In the hybridoma method, a mouse or other suitable host animal, such as a hamster, is immunized as described herein above to elicit lymphocytes that produce or are capable of producing antibodies that specifically bind to the protein used for immunization (e.g., a purified or recombinant TREM1 protein of the present disclosure). Alternatively, lymphocytes may be immunized in vitro. The lymphocytes are then fused with myeloma cells using a suitable fusing agent, such as polyethylene glycol, to form hybridoma cells (Goding, Monoclonal Antibodies: Principles and Practice, p59-103 (Academic Press, 1986)).

[0273] The immunizing agent will typically include an antigenic protein (e.g., a purified or recombinant TREM1 protein of the present disclosure) or a fusion variant thereof. Generally, peripheral blood lymphocytes ("PBLs") are used if cells of human origin are desired, or spleen or lymph node cells are used if non-human mammalian sources are desired. The lymphocytes are then fused with an immortalized cell line using a suitable fusing agent, such as polyethylene glycol, to form a hybridoma cell. Goding, Monoclonal Antibodies: Principles and Practice, Academic Press (1986), p59-103.

[0274] Immortalized cell lines are usually transformed mammalian cells, particularly myeloma cells of rodent, bovine, or human origin. Rat or mouse myeloma cell lines are usually used. The prepared hybridoma cells are then seeded and grown in a suitable culture medium, preferably containing one or more substances that inhibit the growth or survival of the unfused, parental myeloma cells. For example, if the parental myeloma cells lack the enzyme hypoxanthine guanine phosphoribosyltransferase (HGPRT or HPRT), the hybridoma culture medium usually contains hypoxanthine, aminopterin, and thymidine (HAT medium), substances that prevent the growth of HGPRT-deficient cells.

[0275] Preferred immortalized myeloma cells are those that fuse efficiently, support stable high-level production of antibody by the selected antibody-producing cells, and are sensitive to a medium such as HAT medium. Among these, mouse myeloma lines such as those derived from MOPC-21 and MPC-11 mouse tumors (available from the Salk Institute Cell Distribution Center, San Diego, California, USA) and SP-2 cells and their derivatives (e.g., X63-Ag8-653) (available from the American Type Culture Collection, Manassas, Virginia, USA) are preferred. Human myeloma and mouse-human heteromyeloma cell lines have also been described for the production of human monoclonal antibodies (Kozbor, J. Immunol., 133:3001 (1984); Brodeur et al., Monoclonal Antibody Production Techniques and Applications, p51-63 (Marcel Dekker, Inc., New York, 1987)).

[0276] The culture medium in which the hybridoma cells are growing is assayed for production of monoclonal antibodies directed against the antigen (e.g., a TREM1 protein of the present disclosure). Preferably, the binding specificity of the monoclonal antibodies produced by the hybridoma cells is determined by immunoprecipitation or by an in vitro binding assay, such as radioimmunoassay (RIA) or enzyme-linked immunosorbent assay (ELISA).

[0277] The culture medium in which the hybridoma cells are cultured can be assayed for the presence of monoclonal antibodies directed against the desired antigen (e.g., a TREM1 protein of the present disclosure). Preferably, the binding affinity and specificity of the monoclonal antibody can be determined by immunoprecipitation or by an in vitro binding assay, such as radioimmunoassay (RIA) or enzyme-linked immunosorbent assay (ELISA). Such techniques and assays are known in the art. For example, binding affinity can be determined by the Scatchard analysis of Munson et al., Anal. Biochem., 107:220 (1980).

[0278] After hybridoma cells that produce antibodies of the desired specificity, affinity, and / or activity are identified, the clones may be subcloned by limiting dilution procedures and grown by standard methods (Goding, supra). Suitable culture media for this purpose include, for example, D-MEM or RPMI-1640 medium. Additionally, hybridoma cells may be grown in vivo as tumors in a mammal.

[0279] The monoclonal antibodies secreted by the subclones are suitably separated from the culture medium, ascites fluid, or serum by conventional immunoglobulin purification procedures such as, for example, protein A-Sepharose chromatography, hydroxylapatite chromatography, gel electrophoresis, dialysis, affinity chromatography, and other methods as described above.

[0280] Anti-TREM1 monoclonal antibodies can also be produced by recombinant DNA methods, such as those disclosed in U.S. Patent No. 4,816,567 and described above. DNA encoding the monoclonal antibodies is readily isolated and sequenced by conventional procedures (e.g., by using oligonucleotide probes that specifically bind to genes encoding the heavy and light chains of murine antibodies). Hybridoma cells serve as a preferred source of such DNA. Once isolated, the DNA is placed into an expression vector and then transfected into host cells that do not otherwise produce immunoglobulin proteins, such as E. coli cells, simian COS cells, Chinese hamster ovary (CHO) cells, or myeloma cells, to synthesize the monoclonal antibody in such recombinant host cells. Reviews of recombinant expression of antibody-encoding DNA in bacteria include Skerra et al., Curr. Opin. Immunol., 5:256-262 (1993) and Pluckthun, Immunol. Rev. 130:151-188 (1992).

[0281] In certain embodiments, anti-TREM1 antibodies can be isolated from antibody phage libraries generated using the techniques described in McCafferty et al., Nature, 348:552-554 (1990). Clackson et al., Nature, 352:624-628 (1991) and Marks et al., J. Mol. Biol., 222:581-597 (1991) described the isolation of murine and human antibodies, respectively, from phage libraries. Subsequent publications have described the generation of high-affinity (nanomolar ("nM") range) human antibodies by strategies for constructing very large phage libraries (Waterhouse et al., Nucl. Acids Res., 21:2265-2266 (1993)), chain shuffling (Marks et al., Bio / Technology, 10:779-783 (1992)), and combinatorial infection and in vivo recombination. These techniques are therefore viable alternatives to traditional monoclonal antibody hybridoma techniques for the isolation of monoclonal antibodies of desired specificity (eg, those that bind to the TREM1 proteins of the present disclosure).

[0282] DNA encoding antibodies or fragments thereof can also be modified, for example, by substituting coding sequences for human heavy and light chain constant domains for the homologous murine sequences, or by covalently joining an immunoglobulin coding sequence to all or part of the coding sequence of a non-immunoglobulin polypeptide (U.S. Pat. No. 4,816,567; Morrison et al., Proc. Natl. Acad. Sci. USA, 81:6851 (1984)). Typically, such non-immunoglobulin polypeptides are substituted for the constant domains of an antibody, or they are substituted for the variable domains of one antigen-binding site of an antibody, to create a chimeric bivalent antibody containing one antigen-binding site with specificity for an antigen and another antigen-binding site with specificity for a different antigen.

[0283] Monoclonal antibodies described herein (e.g., anti-TREM1 antibodies or fragments thereof of the present disclosure) can be monovalent, and their preparation is well known in the art. For example, one method involves recombinant expression of an immunoglobulin light chain and a modified heavy chain. The heavy chain is generally truncated at some point in the Fc region to prevent heavy chain cross-linking. Alternatively, relevant cysteine ​​residues can be substituted with another amino acid residue or deleted to prevent cross-linking. In vitro methods are also suitable for preparing monovalent antibodies. Digestion of antibodies to produce fragments thereof, particularly Fab fragments, can be accomplished using routine techniques known in the art.

[0284] Chimeric or hybrid anti-TREM1 antibodies can also be prepared in vitro using known methods in synthetic protein chemistry, including those involving crosslinking agents. For example, immunotoxins can be constructed using a disulfide exchange reaction or by forming a thioether bond. Examples of suitable reagents for this purpose include iminothiolate and methyl-4-mercaptobutyrimidate.

[0285] (3) Humanized antibodies The anti-TREM1 antibodies or antibody fragments thereof of the present disclosure may further include humanized or human antibodies. Humanized forms of non-human (e.g., murine) antibodies are chimeric immunoglobulins, immunoglobulin chains, or fragments thereof (such as Fab, Fab'-SH, Fv, scFv, F(ab')2, or other antigen-binding subsequences of antibodies) that contain minimal sequence derived from non-human immunoglobulin. Humanized antibodies comprise human immunoglobulins (recipient antibodies) in which residues from a complementarity-determining region (CDR) of the recipient are replaced by residues from a CDR of a non-human species (donor antibody) such as mouse, rat, or rabbit having the desired specificity, affinity, and capacity. In some examples, Fv framework residues of the human immunoglobulin are replaced by corresponding non-human residues. Humanized antibodies may also comprise residues that are found neither in the recipient antibody nor in the imported CDR or framework sequences. Generally, a humanized antibody will comprise substantially all of at least one, and usually two, variable domains, in which all or substantially all of the CDR regions correspond to those of a non-human immunoglobulin and all or substantially all of the FR regions are human immunoglobulin consensus sequences. The humanized antibody optimally also will comprise at least a portion of an immunoglobulin constant region (Fc), typically that of a human immunoglobulin. Jones et al., Nature 321: 522-525 (1986); Riechmann et al., Nature 332: 323-329 (1988); and Presta, Curr. Opin. Struct. Biol. 2: 593-596 (1992).

[0286] Methods for humanizing non-human anti-TREM1 antibodies are well known in the art. Generally, humanized antibodies have one or more amino acid residues introduced into them from a non-human source. These non-human amino acid residues are often referred to as "import" residues, usually taken from an "import" variable domain. Humanization can be performed according to the methods of Winter and coworkers, Jones et al., Nature 321:522-525 (1986); Riechmann et al., Nature 332:323-327 (1988); Verhoeyen et al., Science 239:1534-1536 (1988), or essentially by substituting rodent CDR or CDR sequences for the corresponding sequences of a human antibody. Such "humanized" antibodies are thus chimeric antibodies (U.S. Pat. No. 4,816,567), in which substantially less than an intact human variable domain has been substituted by the corresponding sequence from a non-human species. In practice, humanized antibodies are typically human antibodies in which some CDR residues and possibly some FR residues are substituted by residues from analogous sites in rodent antibodies.

[0287] The selection of human variable domains, both light and heavy, to be used in the production of humanized antibodies is crucial to reducing antigenicity. According to the so-called "best fit" method, the sequence of the variable domain of a rodent antibody is screened against the entire library of known human variable domain sequences. The human sequence that is closest to that of the rodent is then accepted as the human framework (FR) of the humanized antibody. Sims et al., J. Immunol., 151:2296 (1993); Chothia et al., J. Mol. Biol., 196:901 (1987). Another method uses a specific framework derived from the consensus sequence of all human antibodies of a particular light or heavy chain subgroup. The same framework can be used for several different humanized antibodies. Carter et al., Proc. Nat'l Acad. Sci. USA 89:4285 (1992); Presta et al., J. Immunol. 151:2623 (1993).

[0288] It is also important that antibodies be humanized with retention of high affinity for the antigen and other favorable biological properties. To achieve this goal, according to a preferred method, humanized antibodies are prepared by a process of analyzing the parental sequences and various conceptual humanized products using three-dimensional models of the parental and humanized sequences. Three-dimensional immunoglobulin models are commonly available and are familiar to those skilled in the art. Computer programs are available that illustrate and display probable three-dimensional conformational structures of selected candidate immunoglobulin sequences. Inspection of these displays permits analysis of the likely role of the residues in the function of the candidate immunoglobulin sequence, i.e., analysis of residues that influence the ability of the candidate immunoglobulin to bind to its antigen. In this manner, FR residues can be selected and combined from the recipient and import sequences to achieve the desired antibody characteristic, such as increased affinity for the target antigen(s) (e.g., the TREM1 protein of the present disclosure). In general, the CDR residues are directly and most substantially involved in influencing antigen binding.

[0289] Various forms of humanized anti-TREM1 antibodies are contemplated. For example, the humanized anti-TREM1 antibody can be an antibody fragment, such as a Fab, that is optionally conjugated to one or more TREM1 ligands, such as HSP60. Alternatively, the humanized anti-TREM1 antibody can be an intact antibody, such as an intact IgG1 antibody.

[0290] (4) Human antibodies Alternatively, human anti-TREM1 antibodies can be generated. For example, it is now possible to produce transgenic animals (e.g., mice) that are capable, upon immunization, of producing a full repertoire of human antibodies in the absence of endogenous immunoglobulin production. Expression of antibody heavy chain joining regions (J) in chimeric and germ-line mutant mice has been shown to be beneficial. HHomozygous deletion of the .gt; (Ig) gene results in complete inhibition of endogenous antibody production. Transfer of the human germ-line immunoglobulin gene array in such germ-line mutant mice results in the production of human antibodies upon antigen challenge. See, e.g., Jakobovits et al., Proc. Nat'l Acad. Sci. USA 90:2551 (1993); Jakobovits et al., Nature 362:255-258 (1993); Bruggermann et al., Year in Immunol. 7:33 (1993); U.S. Pat. No. 5,591,669 and WO 97 / 17852.

[0291] Alternatively, pha...

Claims

1. a. a VH comprising HVR-H1 comprising the amino acid sequence of SEQ ID NO: 123, HVR-H2 comprising the amino acid sequence of SEQ ID NO: 148, and HVR-H3 comprising the amino acid sequence of SEQ ID NO: 205, and a VL comprising HVR-L1 comprising the amino acid sequence of SEQ ID NO: 24, HVR-L2 comprising the amino acid sequence of SEQ ID NO: 38, and HVR-L3 comprising the amino acid sequence of SEQ ID NO: 73; b. a VH comprising HVR-H1 comprising the amino acid sequence of SEQ ID NO: 123, HVR-H2 comprising the amino acid sequence of SEQ ID NO: 148, and HVR-H3 comprising the amino acid sequence of SEQ ID NO: 209, and a VL comprising HVR-L1 comprising the amino acid sequence of SEQ ID NO: 25, HVR-L2 comprising the amino acid sequence of SEQ ID NO: 34, and HVR-L3 comprising the amino acid sequence of SEQ ID NO: 78; c. a VH comprising HVR-H1 comprising the amino acid sequence of SEQ ID NO: 123, HVR-H2 comprising the amino acid sequence of SEQ ID NO: 150, and HVR-H3 comprising the amino acid sequence of SEQ ID NO: 210, and a VL comprising HVR-L1 comprising the amino acid sequence of SEQ ID NO: 14, HVR-L2 comprising the amino acid sequence of SEQ ID NO: 30, and HVR-L3 comprising the amino acid sequence of SEQ ID NO: 79; d. a VH comprising an HVR-H1 comprising the amino acid sequence of SEQ ID NO: 122, an HVR-H2 comprising the amino acid sequence of SEQ ID NO: 147, and an HVR-H3 comprising the amino acid sequence of SEQ ID NO: 226, and a VL comprising an HVR-L1 comprising the amino acid sequence of SEQ ID NO: 14, an HVR-L2 comprising the amino acid sequence of SEQ ID NO: 30, and an HVR-L3 comprising the amino acid sequence of SEQ ID NO: 97; e. a VH comprising HVR-H1 comprising the amino acid sequence of SEQ ID NO: 135, HVR-H2 comprising the amino acid sequence of SEQ ID NO: 167, and HVR-H3 comprising the amino acid sequence of SEQ ID NO: 227, and a VL comprising HVR-L1 comprising the amino acid sequence of SEQ ID NO: 11, HVR-L2 comprising the amino acid sequence of SEQ ID NO: 30, and HVR-L3 comprising the amino acid sequence of SEQ ID NO: 98; f. a VH comprising an HVR-H1 comprising the amino acid sequence of SEQ ID NO: 135, an HVR-H2 comprising the amino acid sequence of SEQ ID NO: 167, and an HVR-H3 comprising the amino acid sequence of SEQ ID NO: 227, and a VL comprising an HVR-L1 comprising the amino acid sequence of SEQ ID NO: 14, an HVR-L2 comprising the amino acid sequence of SEQ ID NO: 30, and an HVR-L3 comprising the amino acid sequence of SEQ ID NO: 99; g. a VH comprising an HVR-H1 comprising the amino acid sequence of SEQ ID NO: 136, an HVR-H2 comprising the amino acid sequence of SEQ ID NO: 167, and an HVR-H3 comprising the amino acid sequence of SEQ ID NO: 228, and a VL comprising an HVR-L1 comprising the amino acid sequence of SEQ ID NO: 11, an HVR-L2 comprising the amino acid sequence of SEQ ID NO: 30, and an HVR-L3 comprising the amino acid sequence of SEQ ID NO: 100; h. a VH comprising HVR-H1 comprising the amino acid sequence of SEQ ID NO: 120, HVR-H2 comprising the amino acid sequence of SEQ ID NO: 144, and HVR-H3 comprising the amino acid sequence of SEQ ID NO: 175, and a VL comprising HVR-L1 comprising the amino acid sequence of SEQ ID NO: 11, HVR-L2 comprising the amino acid sequence of SEQ ID NO: 30, and HVR-L3 comprising the amino acid sequence of SEQ ID NO: 43; i. a VH comprising HVR-H1 comprising the amino acid sequence of SEQ ID NO: 120, HVR-H2 comprising the amino acid sequence of SEQ ID NO: 144, and HVR-H3 comprising the amino acid sequence of SEQ ID NO: 176, and a VL comprising HVR-L1 comprising the amino acid sequence of SEQ ID NO: 12, HVR-L2 comprising the amino acid sequence of SEQ ID NO: 31, and HVR-L3 comprising the amino acid sequence of SEQ ID NO: 44; j. a VH comprising an HVR-H1 comprising the amino acid sequence of SEQ ID NO: 121, an HVR-H2 comprising the amino acid sequence of SEQ ID NO: 146, and an HVR-H3 comprising the amino acid sequence of SEQ ID NO: 179, and a VL comprising an HVR-L1 comprising the amino acid sequence of SEQ ID NO: 14, an HVR-L2 comprising the amino acid sequence of SEQ ID NO: 30, and an HVR-L3 comprising the amino acid sequence of SEQ ID NO: 47; k. a VH comprising an HVR-H1 comprising the amino acid sequence of SEQ ID NO: 134, an HVR-H2 comprising the amino acid sequence of SEQ ID NO: 144, and an HVR-H3 comprising the amino acid sequence of SEQ ID NO: 215, and a VL comprising an HVR-L1 comprising the amino acid sequence of SEQ ID NO: 14, an HVR-L2 comprising the amino acid sequence of SEQ ID NO: 30, and an HVR-L3 comprising the amino acid sequence of SEQ ID NO: 86; l. a VH comprising HVR-H1 comprising the amino acid sequence of SEQ ID NO: 129, HVR-H2 comprising the amino acid sequence of SEQ ID NO: 146, and HVR-H3 comprising the amino acid sequence of SEQ ID NO: 217, and a VL comprising HVR-L1 comprising the amino acid sequence of SEQ ID NO: 13, HVR-L2 comprising the amino acid sequence of SEQ ID NO: 32, and HVR-L3 comprising the amino acid sequence of SEQ ID NO: 88; m. a VH comprising an HVR-H1 comprising the amino acid sequence of SEQ ID NO: 138, an HVR-H2 comprising the amino acid sequence of SEQ ID NO: 170, and an HVR-H3 comprising the amino acid sequence of SEQ ID NO: 233, and a VL comprising an HVR-L1 comprising the amino acid sequence of SEQ ID NO: 14, an HVR-L2 comprising the amino acid sequence of SEQ ID NO: 30, and an HVR-L3 comprising the amino acid sequence of SEQ ID NO: 105; n. VH comprising HVR-H1 comprising the amino acid sequence of SEQ ID NO: 122, HVR-H2 comprising the amino acid sequence of SEQ ID NO: 147, and HVR-H3 comprising the amino acid sequence of SEQ ID NO: 246, and VL comprising HVR-L1 comprising the amino acid sequence of SEQ ID NO: 11, HVR-L2 comprising the amino acid sequence of SEQ ID NO: 30, and HVR-L3 comprising the amino acid sequence of SEQ ID NO: 118; o. a VH comprising an HVR-H1 comprising the amino acid sequence of SEQ ID NO: 124, an HVR-H2 comprising the amino acid sequence of SEQ ID NO: 161, and an HVR-H3 comprising the amino acid sequence of SEQ ID NO: 247, and a VL comprising an HVR-L1 comprising the amino acid sequence of SEQ ID NO: 22, an HVR-L2 comprising the amino acid sequence of SEQ ID NO: 31, and an HVR-L3 comprising the amino acid sequence of SEQ ID NO: 119; p. a VH comprising an HVR-H1 comprising the amino acid sequence of SEQ ID NO: 124, an HVR-H2 comprising the amino acid sequence of SEQ ID NO: 149, and an HVR-H3 comprising the amino acid sequence of SEQ ID NO: 206, and a VL comprising an HVR-L1 comprising the amino acid sequence of SEQ ID NO: 11, an HVR-L2 comprising the amino acid sequence of SEQ ID NO: 30, and an HVR-L3 comprising the amino acid sequence of SEQ ID NO: 75; or q. A VH comprising an HVR-H1 comprising the amino acid sequence of SEQ ID NO: 132, an HVR-H2 comprising the amino acid sequence of SEQ ID NO: 149, and an HVR-H3 comprising the amino acid sequence of SEQ ID NO: 208, and a VL comprising an HVR-L1 comprising the amino acid sequence of SEQ ID NO: 14, an HVR-L2 comprising the amino acid sequence of SEQ ID NO: 30, and an HVR-L3 comprising the amino acid sequence of SEQ ID NO:

77.

2. An isolated antibody that specifically binds to TREM1, comprising:

2. 2. The isolated antibody of claim 1, comprising a light chain variable domain comprising an amino acid sequence selected from SEQ ID NOs: 318, 319, 322, 349, 351, 333-355, 362, 364, 373-376, 381, 394, and 395; and / or a heavy chain variable domain comprising an amino acid sequence selected from SEQ ID NOs: 398, 399, 402, 429, 431, 433-435, 442, 444, 453-456, 461, 474, and 475.

3. a. a VH comprising the amino acid sequence of SEQ ID NO:429 and a VL comprising the amino acid sequence of SEQ ID NO:349; b. a VH comprising the amino acid sequence of SEQ ID NO:434 and a VL comprising the amino acid sequence of SEQ ID NO:354; c. a VH comprising the amino acid sequence of SEQ ID NO: 435 and a VL comprising the amino acid sequence of SEQ ID NO: 355; d. a VH comprising the amino acid sequence of SEQ ID NO:453 and a VL comprising the amino acid sequence of SEQ ID NO:373; e. a VH comprising the amino acid sequence of SEQ ID NO:454 and a VL comprising the amino acid sequence of SEQ ID NO:374; f. a VH comprising the amino acid sequence of SEQ ID NO:455 and a VL comprising the amino acid sequence of SEQ ID NO:375; g. a VH comprising the amino acid sequence of SEQ ID NO:456 and a VL comprising the amino acid sequence of SEQ ID NO:376; h. a VH comprising the amino acid sequence of SEQ ID NO: 398 and a VL comprising the amino acid sequence of SEQ ID NO: 318; i. a VH comprising the amino acid sequence of SEQ ID NO: 399 and a VL comprising the amino acid sequence of SEQ ID NO: 319; j. a VH comprising the amino acid sequence of SEQ ID NO:402 and a VL comprising the amino acid sequence of SEQ ID NO:322; k. a VH comprising the amino acid sequence of SEQ ID NO:422 and a VL comprising the amino acid sequence of SEQ ID NO:362; l. a VH comprising the amino acid sequence of SEQ ID NO:444 and a VL comprising the amino acid sequence of SEQ ID NO:364; m. a VH comprising the amino acid sequence of SEQ ID NO:461 and a VL comprising the amino acid sequence of SEQ ID NO:381; n. a VH comprising the amino acid sequence of SEQ ID NO: 474 and a VL comprising the amino acid sequence of SEQ ID NO: 394; o. a VH comprising the amino acid sequence of SEQ ID NO: 475 and a VL comprising the amino acid sequence of SEQ ID NO: 395; p. a VH comprising the amino acid sequence of SEQ ID NO: 431 and a VL comprising the amino acid sequence of SEQ ID NO: 351; or q. A VH comprising the amino acid sequence of SEQ ID NO: 433 and a VL comprising the amino acid sequence of SEQ ID NO: 353 2. The isolated antibody of claim 1 , comprising:

4. The isolated antibody of any one of claims 1-3, which blocks ligand binding and inhibits ligand-induced signaling in a soluble state; and induces TREM1-dependent gene expression in a plate-bound state and does not induce TREM1-dependent gene expression in a soluble state.

5. The isolated antibody of any one of claims 1-3, which is of the IgG1, IgG2, IgG3, or IgG4 isotype.

6. The isolated antibody of any one of claims 1-3, which binds to an inhibitory Fc receptor.

7. The isolated antibody of claim 6, wherein the inhibitory Fc receptor is inhibitory Fc-gamma receptor IIB (FcγIIB).

8. the isolated antibody has a human IgG1 isotype and comprises one or more amino acid substitutions in the Fc region at residue positions selected from the group consisting of N297A, D265A, D270A, L234A, L235A, G237A, C226S, C229S, E233P, L234V, L234F, L235E, P331S, S267E, L328F, A330L, M252Y, S254T, T256E, L328E, P238D, S267E, L328F, E233D, G237D, H268D, P271G, A330R, and any combination thereof (residue numbering according to EU or Kabat numbering), or comprises an amino acid deletion in the Fc region at a position corresponding to glycine 236; b. the isolated antibody has an IgG1 isotype and comprises an IgG2 isotype heavy chain constant domain 1 (CH1) and hinge region, optionally wherein the IgG2 isotype CH1 and hinge region comprise the amino acid sequence of ASTKGPSVFP LAPCSRSTSE STAALGCLVK DYFPEPVTVS WNSGALTSGVHTFPAVLQSS GLYSLSSVVT VPSSNFGTQT YTCNVDHKPS NTKVDKTVERKCCVECPPCP (SEQ ID NO: 476), and optionally wherein the antibody Fc region comprises a S267E amino acid substitution, a L328F amino acid substitution, or both, and / or a N297A or N297Q amino acid substitution (wherein residue numbering is according to EU numbering); c. the isolated antibody has an IgG2 isotype and comprises one or more amino acid substitutions in the Fc region at residue positions selected from the group consisting of P238S, V234A, G237A, H268A, H268Q, V309L, A330S, P331S, C214S, C232S, C233S, S267E, L328F, M252Y, S254T, T256E, H268E, N297A, N297Q, A330L, and any combination thereof (residue numbering according to EU or Kabat numbering); d. the isolated antibody has a human IgG4 isotype and comprises one or more amino acid substitutions in the Fc region at residue positions selected from the group consisting of L235A, G237A, S228P, L236E, S267E, E318A, L328F, M252Y, S254T, T256E, E233P, F234V, L234A / F234A, S228P, S241P, L248E, T394D, N297A, N297Q, L235E, and any combination thereof (residue numbering according to EU or Kabat numbering); or e. the isolated antibody has a hybrid IgG2 / 4 isotype, and optionally comprises an amino acid sequence comprising amino acids 118-260 of human IgG2 and amino acids 261-447 of human IgG4, wherein the numbering of residues is according to EU or Kabat numbering; The isolated antibody of any one of claims 1-3.

9. An isolated nucleic acid comprising a nucleic acid sequence encoding the isolated antibody of any one of claims 1-3.

10. A vector comprising the nucleic acid of claim 9.

11. 10. An isolated host cell comprising the nucleic acid of claim 9.

12. A method for producing an antibody that binds to TREM1, comprising culturing the cell of claim 11 so that the antibody is produced.

13. The method of claim 12, further comprising recovering the antibody produced by the cells.

14. A medicament comprising a therapeutically effective amount of the isolated antibody of any one of claims 1-3.

15. The pharmaceutical composition of claim 14, further comprising at least one additional therapeutic agent selected from an antibody that specifically binds to a stimulatory checkpoint molecule, an antibody that specifically binds to an inhibitory cytokine, an agonistic antibody that specifically binds to a stimulatory checkpoint protein, a stimulatory cytokine, and a standard or investigational anti-cancer therapy.

16. a. the antibody that specifically binds to an inhibitory checkpoint molecule is selected from the group consisting of an anti-PD-L1 antibody, an anti-CTLA-4 antibody, an anti-PD-L2 antibody, an anti-PD-1 antibody, an anti-B7-H3 antibody, an anti-B7-H4 antibody, an anti-HVEM antibody, an anti-B- and T-lymphocyte attenuator (BTLA) antibody, an anti-killer inhibitory receptor (KIR) antibody, an anti-GAL9 antibody, an anti-TIM3 antibody, an anti-A2AR antibody, an anti-LAG-3 antibody, an anti-phosphatidylserine antibody, an anti-CD27 antibody, and any combination thereof; b. the antibody that specifically binds to an inhibitory cytokine is selected from the group consisting of an anti-CCL2 antibody, an anti-CSF-1 antibody, an anti-IL-2 antibody, and any combination thereof; c. the agonist antibody that specifically binds to a stimulatory checkpoint protein is selected from the group consisting of an agonist anti-CD40 antibody, an agonist anti-OX40 antibody, an agonist anti-ICOS antibody, an agonist anti-CD28 antibody, an agonist anti-CD137 / 4-1BB antibody, an agonist anti-CD27 antibody, an agonist anti-glucocorticoid-induced TNFR-related protein GITR antibody, and any combination thereof; d. the stimulatory cytokine is selected from the group consisting of TNF-α, IL-10, IL-6, IL-8, CRP, a TGF-β member of the chemokine protein family, an IL20 family member, IL-33, LIF, OSM, CNTF, TGF-β, IL-11, IL-12, IL-17, IL-8, IL-23, IFN-α, IFN-β, IL-2, IL-18, GM-CSF, G-CSF, and any combination thereof; and / or e. the standard or investigational anti-cancer therapy is selected from the group consisting of radiation therapy, cytotoxic chemotherapy, targeted therapy, hormonal therapy, imatinib (Gleevec®), trastuzumab (Herceptin®), bevacizumab (Avastin®), ofatumumab (Arzerra®), rituximab (Rituxan®, MabThera®, Zytux®), cryotherapy, ablation, radiofrequency ablation, adoptive cell transfer (ACT), chimeric antigen receptor T cell transfer (CAR-T), vaccine therapy, and cytokine therapy; The pharmaceutical composition according to claim 15.