The FGK4.5 monoclonal antibody reacts with mouse CD40 also known as Bp50. CD40 is a 48 kDa type I transmembrane glycoprotein that belongs to the tumor necrosis factor receptor (TNFR) superfamily. CD40 is expressed broadly on antigen-presenting cells (APCs) such as dendritic cells, B cells, macrophages, and monocytes as well as non-immune endothelial cells, basal epithelial cells, and a range of tumors. Upon binding to its ligand CD154, CD40 acts as a costimulatory molecule for the activation of B cells, dendritic cells, monocytes, and other APCs. CD40 plays roles in B cell activation, differentiation, proliferation and Ig isotype switching as well as dendritic cell maturation. Agonistic CD40 monoclonal antibodies have been shown to activate APCs and promote anti-tumor T cell responses. The FGK4.5 antibody is an agonistic antibody that has been shown to activate CD40 expressing APCs. FGK4.5 can also be used to inhibit CD40/CD154 interaction in vitro and in vivo.

The 16-10A1 monoclonal antibody reacts with mouse CD80 also known as B7-1. CD80 is a 60 kDa Ig superfamily member and is expressed by activated B cells and constitutively by monocytes and dendritic cells. This ligand binds to CD28 to provide a costimulatory signal necessary for T cell activation and survival, and cytokine production. Additionally, CD80 binds to CTLA-4 which inhibits T cells. This antibody has been shown to block CD80 in vivo.

The R17 217.1.3/TIB-219 monoclonal antibody reacts with mouse CD71 also known as transferrin receptor protein 1 (TfR1). CD71 is a 170-180 kDa type II homodimeric transmembrane glycoprotein which is expressed on the surface of proliferating cells, reticulocytes, and erythroid precursors. CD71 plays a role in the control of cellular proliferation and is required for iron import from transferrin into cells by endocytosis. Due to its important role in proliferation and cellular iron intake as well as the fact that many cancerous cells express high levels of CD71 it is being explored as a potential new target in cases of human leukemia & lymphoma. The R17 217.1.3/TIB-219 antibody has been shown to deplete CD71+ erythroid splenocytes.

The 390 monoclonal antibody reacts with mouse CD31, also known as PECAM-1 (platelet endothelial cell adhesion molecule). CD31 is a 130-140 kDa glycoprotein and member of the immunoglobulin superfamily. CD31 is expressed constitutively on the surface of adult and embryonic endothelial cells and is weakly expressed on platelets, granulocytes, monocytes/macrophages, dendritic cells, and T and B cell subsets. CD31 mediates homophilic and heterophilic cell-cell adhesion and is critical for cell-cell interactions. Ligands for CD31 are reported as CD38 and vitronectin receptor (αvβ3 integrin, CD51/CD61). The 390 antibody has been shown to inhibit in vivo functions mediated by CD31.

The AFS98 monoclonal antibody reacts with mouse colony stimulating factor 1 receptor (CSF1R), also known as macrophage colony-stimulating factor receptor (M-CSFR), and CD115. CSF1R is a single-pass type I membrane protein and member of the platelet-derived growth factor receptor family. In mice CSF1R is expressed by monocytes/macrophages, peritoneal exudate cells, plasmacytoid and conventional dendritic cells, and osteoclasts. CSF1R is a receptor for CSF1 and CSF1 signaling through CSF1R regulates the proliferation and differentiation of cells in the monocytic lineage. The AFS98 antibody has been reported to deplete macrophages and block CSFR1 in vivo.

The UC10-4F10-11 monoclonal antibody reacts with mouse CTLA-4 (cytotoxic T lymphocyte antigen-4) also known as CD152. CTLA-4 is a 33 kDa cell surface receptor encoded by the Ctla4 gene that belongs to the CD28 family of the Ig superfamily. CTLA-4 is expressed on activated T and B lymphocytes. CTLA-4 is structurally similar to the T-cell co-stimulatory protein, CD28, and both molecules bind to the B7 family members B7-1 (CD80) and B7-2 (CD86). Upon ligand binding, CTLA-4 negatively regulates cell-mediated immune responses. CTLA-4 plays roles in induction and/or maintenance of immunological tolerance, thymocyte development, and regulation of protective immunity. The critical role of CTLA-4 in immune down-regulation has been demonstrated in CTLA-4 deficient mice, which succumb at 3-5 weeks of age due to the development of a lymphoproliferative disease. CTLA-4 is among a group of inhibitory receptors being explored as cancer treatment targets through immune checkpoint blockade. The UC10-4F10-11 antibody has been shown to promote T cell co-stimulation by blocking CTLA-4 binding to the B7 co-receptors, allowing for CD28 binding.

The PK136 monoclonal antibody reacts with mouse NK1.1 also known as CD161b/CD161c, KLRB1, NKR-P1A and Ly-55. NK1.1 is a type II integral membrane glycoprotein with a C-type lectin domain and is encoded by the Klrb1c/NKR-P1C gene. NK1.1 plays roles in NK cell activation and differentiation, IFN-γ production, cytotoxic granule release, and is thought to be involved in the generation of Th2 cells. NK1.1 is predominantly expressed as a disulfide-linked homodimer on NK cells however, it is also expressed on NK-T cells, a rare population of T lymphocytes. NK 1.1 is only expressed by C57BL/6, FVB/N, and NZB strains of mice and not AKR, BALB/c, CBA/J, C3H, DBA/1, DBA/2, NOD, SJL, and 129 strains.

The 2.43 monoclonal antibody reacts with mouse CD8α. The CD8 antigen is a transmembrane glycoprotein that acts as a co-receptor for the T cell receptor (TCR). Like the TCR, CD8 binds to class I MHC molecules displayed by antigen presenting cells (APC). CD8 is primarily expressed on the surface of cytotoxic T cells, but can also be found on thymocytes, natural killer cells, and some dendritic cell subsets. CD8 most commonly exists as a heterodimer composed of one CD8α and one CD8β chain however, it can also exist as a homodimer composed of two CD8α chains. Both the CD8α and CD8β chains share significant homology to immunoglobulin variable light chains. The molecular weight of each CD8 chain is approximately 34 kDa. The 2.43 antibody exhibits depleting activity when used in vivo.

The 9H10 monoclonal antibody reacts with mouse CTLA-4 (cytotoxic T lymphocyte antigen-4) also known as CD152. CTLA-4 is a 33 kDa cell surface receptor encoded by the Ctla4 gene that belongs to the CD28 family of the Ig superfamily. CTLA-4 is expressed on activated T and B lymphocytes. CTLA-4 is structurally similar to the T-cell co-stimulatory protein, CD28, and both molecules bind to the B7 family members B7-1 (CD80) and B7-2 (CD86). Upon ligand binding, CTLA-4 negatively regulates cell-mediated immune responses. CTLA-4 plays roles in induction and/or maintenance of immunological tolerance, thymocyte development, and regulation of protective immunity. The critical role of CTLA-4 in immune down-regulation has been demonstrated in CTLA-4 deficient mice, which succumb at 3-5 weeks of age due to the development of a lymphoproliferative disease. CTLA-4 is among a group of inhibitory receptors being explored as cancer treatment targets through immune checkpoint blockade. The 9H10 antibody has been shown to promote T cell co-stimulation by blocking CTLA-4 binding to the B7 co-receptors, allowing for CD28 binding.

The MAR1-5A3 monoclonal antibody reacts with mouse IFNAR-1 (IFN alpha/beta receptor subunit 1). IFNAR-1 is coexpressed with IFNAR-2 on nearly all cell types and together these two subunits make up the heterodimeric Type I IFN Receptor complex. Type I IFNs (IFN-α/β) bind to the Type I IFN Receptor complex to induce cellular responses including induction of anti-viral, anti-microbial, anti-tumor, and autoimmune responses as well as to regulate the activation, proliferation, and differentiation of many cell types. The MAR1-5A3 antibody has been shown to inhibit Type I IFN receptor signaling in vitro and in vivo.

The YTS 169.4 monoclonal antibody reacts with mouse CD8α. The CD8 antigen is a transmembrane glycoprotein that acts as a co-receptor for the T cell receptor (TCR). Like the TCR, CD8 binds to class I MHC molecules displayed by antigen presenting cells (APC). CD8 is primarily expressed on the surface of cytotoxic T cells, but can also be found on thymocytes, natural killer cells, and some dendritic cell subsets. CD8 most commonly exists as a heterodimer composed of one CD8α and one CD8β chain however, it can also exist as a homodimer composed of two CD8α chains. Both the CD8α and CD8β chains share significant homology to immunoglobulin variable light chains. The molecular weight of each CD8 chain is approximately 34 kDa. The YTS 169.4 antibody exhibits depleting activity when used in vivo.

The 9D9 monoclonal antibody reacts with mouse CTLA-4 (cytotoxic T lymphocyte antigen-4) also known as CD152. CTLA-4 is a 33 kDa cell surface receptor encoded by the Ctla4 gene that belongs to the CD28 family of the Ig superfamily. CTLA-4 is expressed on activated T and B lymphocytes. CTLA-4 is structurally similar to the T-cell co-stimulatory protein, CD28, and both molecules bind to the B7 family members B7-1 (CD80) and B7-2 (CD86). Upon ligand binding, CTLA-4 negatively regulates cell-mediated immune responses. CTLA-4 plays roles in induction and/or maintenance of immunological tolerance, thymocyte development, and regulation of protective immunity. The critical role of CTLA-4 in immune down-regulation has been demonstrated in CTLA-4 deficient mice, which succumb at 3-5 weeks of age due to the development of a lymphoproliferative disease. CTLA-4 is among a group of inhibitory receptors being explored as cancer treatment targets through immune checkpoint blockade.

The C18.2 monoclonal antibody reacts with mouse interleukin-12 (IL-12) p35. IL-12 is a heterodimeric 70 kDa cytokine consisting of two covalently linked subunits, 40 kDa (p40) and 35 kDa (p35). IL-12 is secreted by activated monocytes, macrophages, and dendritic cells in response to bacterial pathogens or products such as lipopolysaccharides (LPS). IL-12 is a potent regulator of cell-mediated immune responses and plays a key role in the development of Th1 responses, leading to IFNγ and IL-2 production.

The 10F.9G2™ monoclonal antibody reacts with mouse PD-L1 (programmed death ligand 1) also known as B7-H1 or CD274. PD-L1 is a 40 kDa type I transmembrane protein that belongs to the B7 family of the Ig superfamily. PD-L1 is expressed on T lymphocytes, B lymphocytes, NK cells, dendritic cells, as well as IFNγ stimulated monocytes, epithelial cells and endothelial cells. PD-L1 binds to its receptor, PD-1, found on CD4 and CD8 thymocytes as well as activated T and B lymphocytes and myeloid cells. Engagement of PD-L1 with PD-1 leads to inhibition of TCR-mediated T cell proliferation and cytokine production. PD-L1 is thought to play an important role in tumor immune evasion. Induced PD-L1 expression is common in many tumors and results in increased resistance of tumor cells to CD8 T cell mediated lysis. In mouse models of melanoma, tumor growth can be transiently arrested via treatment with antibodies which block the interaction between PD-L1 and PD-1. The 10F.9G2™ antibody has been shown to block the interaction between PD-L1 and PD-1 and between PD-L1 and B7-1 (CD80).

The J43 monoclonal antibody reacts with mouse PD-1 (programmed death-1) also known as CD279. PD-1 is a 50-55 kDa cell surface receptor encoded by the Pdcd1 gene that belongs to the CD28 family of the immunoglobulin superfamily. PD-1 is transiently expressed on CD4 and CD8 thymocytes as well as activated T and B lymphocytes and myeloid cells. PD-1 expression declines after successful elimination of antigen. Additionally, Pdcd1 mRNA is expressed in developing B lymphocytes during the pro-B-cell stage. PD-1’s structure includes a ITIM (immunoreceptor tyrosine-based inhibitory motif) suggesting that PD-1 negatively regulates TCR signals. PD-1 signals via binding its two ligands, PD-L1 and PD-L2 both members of the B7 family. Upon ligand binding, PD-1 signaling inhibits T-cell activation, leading to reduced proliferation, cytokine production, and T-cell death. Additionally, PD-1 is known to play key roles in peripheral tolerance and prevention of autoimmune disease in mice as PD-1 knockout animals show dilated cardiomyopathy, splenomegaly, and loss of peripheral tolerance. Induced PD-L1 expression is common in many tumors including squamous cell carcinoma, colon adenocarcinoma, and breast adenocarcinoma. PD-L1 overexpression results in increased resistance of tumor cells to CD8 T cell mediated lysis. In mouse models of melanoma, tumor growth can be transiently arrested via treatment with antibodies which block the interaction between PD-L1 and its receptor PD-1. For these reasons anti-PD-1 mediated immunotherapies are currently being explored as cancer treatments. The J43 antibody has been shown to block the binding of both mouse PD-L1-Ig and mouse PD-L2-Ig to PD-1.