CD278
CD278 also known as Inducible T-cell COStimulator (ICOS) is a protein that in humans is encoded by the ICOS gene. ICOS is a member of the CD28 and CTLA-4 cell-surface receptor family. It is an immune checkpoint and stimulates T-cell proliferation and cytokine production.
Structure[edit | edit source]
The ICOS protein is a homodimeric protein that is a member of the immunoglobulin superfamily. It is composed of two identical chains, each containing two extracellular domains: an immunoglobulin variable (IgV) domain and an immunoglobulin constant (IgC) domain.
Function[edit | edit source]
ICOS is expressed on activated T cells and binds to its ligand, B7RP-1, on antigen-presenting cells. This interaction provides a costimulatory signal that is essential for T cell proliferation and production of IL4, IL5, and IL13. It also plays a key role in the development of follicular T helper cells (Tfh), a subset of T cells involved in the production of antibodies by B cells.
Clinical significance[edit | edit source]
Abnormal ICOS function has been associated with a number of autoimmune diseases, including rheumatoid arthritis, systemic lupus erythematosus, and multiple sclerosis. In addition, ICOS is a potential target for immunotherapy in cancer, as blocking its function can enhance the anti-tumor response of T cells.
See also[edit | edit source]
References[edit | edit source]
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