CD137 is a member of the tumor necrosis factor (TNF

Tumor necrosis factors

Tumor necrosis factors refers to a group of cytokines family that can cause cell death . The first two members of the family to be identified were:...

) receptor family. Its alternative names are tumor necrosis factor receptor superfamily member 9 (TNFRSF9), 4-1BB and induced by lymphocyte activation (ILA).

Expression

CD137 can be expressed by activated T cells, but to a larger extent on CD8

CD8

CD8 is a transmembrane glycoprotein that serves as a co-receptor for the T cell receptor . Like the TCR, CD8 binds to a major histocompatibility complex molecule, but is specific for the class I MHC protein. There are two isoforms of the protein, alpha and beta, each encoded by a different gene...

 than on CD4

CD4

CD4 is a glycoprotein expressed on the surface of T helper cells, monocytes, macrophages, and dendritic cells. It was discovered in the late 1970s and was originally known as leu-3 and T4 before being named CD4 in 1984...

 T cells. In addition, CD137 expression is found on dendritic cells, follicular dendritic cells, natural killer cells, granulocytes and cells of blood vessel walls at sites of inflammation

Inflammation

Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...

.

Specific effects on cells

The best characterized activity of CD137 is its costimulatory activity for activated T cells. Crosslinking of CD137 enhances T cell proliferation, IL-2 secretion survival and cytolytic activity. Further, it can enhance immune activity to eliminate tumors in mice.

Further reading