OX40 Inhibitor

OX40 belongs to the tumor necrosis factor receptor family. It is mainly expressed on the activated lymphocyte surface. OX40 is an important co-stimulant molecule in the immune response, which can improve the immunosuppressive effect in tumor microenvironment. Enhancing the cytotoxicity of lymphocytes plays an important role in mediating the development of tumor immune response. OX40's value as a drug target primarily lies in the fact that, being transiently expressed after T-cell receptor engagement, it is only upregulated on the most recently antigen-activated T cells within inflammatory lesions. Anti-OX40 monoclonal antibodies have been shown to have clinical utility in advanced cancer.

Molecular Biological Characteristics of OX40

OX40 is also called CD134. OX40L（CD252）is the only ligand of OX40, mainly expressed on the surface of activated antigen presenting cells（APC）as well as natural killer cells and mast cells. In the process of immunomodulation, antigen presenting cells combined with T cells, and antigen peptide -MHC complex was presented to T cells to stimulate T cell activation. At the same time, the OX40L on the surface of APC combined with the costimulatory molecule OX40 on the surface of T cells, which promoted the activation of T cells as the second signal. OX40 has the same effect as CD27, and can promote the proliferation of effector cells and memory cells and regulate the activity of T cells and the production of cytokines.