Anti-Human OX40 (IB9) Antibody (ICH5119A-0.1mg)

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Anti-Human OX40 (IB9) is a recombinant human IgG2 kappa monoclonal antibody raised against human OX40 (CD134, TNFRSF4; UniProt P43489). Supplied as a low-endotoxin, bulk-scale (mg-g), research-use-only reagent, it is well suited to functional immunology studies of the OX40/OX40L costimulatory axis in human cell systems, including T-cell activation, proliferation, and cytokine assays. The human IgG2 backbone, which has weak Fc-effector function relative to IgG1, makes the clone useful for interrogating OX40 signaling with limited Fc-gamma-receptor engagement and for building humanized or fully human antibody test articles. Low endotoxin content (research grade <1 EU/mg; ultra-low <0.5 EU/mg) reduces confounding innate stimulation in primary T-cell and PBMC cultures, and bulk availability supports high-throughput screening, cross-linking optimization, and reproducible large-cohort work. As a human-reactive reagent it is appropriate for in-vitro/ex-vivo functional characterization; investigators requiring in-vivo agonism should note that mouse surrogate clones are typically used for immunocompetent rodent models. All work should be internally validated for the intended application. OX40 (CD134, TNFRSF4) is a member of the tumor necrosis factor receptor superfamily expressed predominantly on activated CD4+ and CD8+ T cells, with induction peaking a day or two after antigen encounter; it is also found on regulatory T cells and some other activated lymphocytes. Its ligand, OX40L (CD252, TNFSF4), is expressed on activated antigen-presenting cells including dendritic cells, B cells, and macrophages. OX40 engagement delivers a costimulatory signal that, via TRAF adaptors and downstream NF-kB and PI3K/Akt pathways, promotes T-cell survival, clonal expansion, effector differentiation, and the generation and maintenance of memory T cells. OX40 signaling can also modulate regulatory T-cell function and stability. Because it amplifies effector T-cell responses and can influence Treg activity, OX40 is an actively studied target for agonist immunotherapy in oncology and for blockade in autoimmune and inflammatory settings.