This mouse monoclonal antibody (clone 4B4-1) reacts with human and monkey CD137, a type I membrane protein and member of the TNF receptor superfamily.

Following activation, it is expressed on multiple immune cells such as natural killer (NK), T, and dendritic cells. CD137 plays a role in cytokine activation, preventing activation-induced cell death and it also plays a role in promoting the activity of cytotoxic T cells. CD137 deficiency in humans has been hypothesized to inhibit differentiation and function of T cells; CD137-deficient mice have been recorded to have impaired T cell cytotoxicity, proliferation, and survival. As an immune stimulator, CD137 can influence the tumor microenvironment by increasing the cytotoxicity of T and NK cells as well as their ability to infiltrate tumors. For these reasons, CD137 represents a strong candidate for cancer immunotherapy. Use this monoclonal antibody in applications requiring detection of CD137, such as flow cytometry (FC).