CD137 is a member of the tumor necrosis factor (
TNF
Tumor necrosis factor (TNF, cachexin, or cachectin; formerly known as tumor necrosis factor alpha or TNF-α) is an adipokine and a cytokine. TNF is a member of the TNF superfamily, which consists of various transmembrane proteins with a homolog ...
) receptor family. Its alternative names are ''tumor necrosis factor receptor superfamily member 9'' (TNFRSF9), 4-1BB and ''induced by lymphocyte activation'' (ILA). It is of interest to immunologists as a co-stimulatory
immune checkpoint
Immune checkpoints are regulators of the immune system. These pathways are crucial for self-tolerance, which prevents the immune system from attacking cells indiscriminately. However, some cancers can protect themselves from attack by stimula ...
molecule.
Expression
CD137 is expressed by activated
T cells
A T cell is a type of lymphocyte. T cells are one of the important white blood cells of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell re ...
of both the
CD4+ and
CD8+
A cytotoxic T cell (also known as TC, cytotoxic T lymphocyte, CTL, T-killer cell, cytolytic T cell, CD8+ T-cell or killer T cell) is a T lymphocyte (a type of white blood cell) that kills cancer cells, cells that are infected by intracellular pa ...
lineages. Although it is thought to function mainly in co-stimulating those cell types to support their activation by antigen presenting cells expressing its ligand (CD137L), CD137 is also expressed on dendritic cells, B cells, NK cells, neutrophils and macrophages.
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.
Interactions
CD137 has been shown to
interact with
TRAF2
TNF receptor-associated factor 2 is a protein that in humans is encoded by the ''TRAF2'' gene.
Function
The protein encoded by this gene is a member of the TNF receptor associated factor (TRAF) protein family. TRAF proteins associate with, an ...
.
As a drug target
Utomilumab
Utomilumab (PF-05082566) targets this receptor to stimulate a more intense immune system attack on cancers.
[Pfizer cancer drug shows promise in combo with Merck's Keytruda. May 2016]
/ref> It is a fully human IgG2 monoclonal antibody. It is in early clinical trials.[ 5 clinical trials are active.PF-05082566 trials]
/ref>
See also
* 4-1BB ligand
* Urelumab
References
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{{DEFAULTSORT:Cd137
Oncology
Immunology