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CTLA4

MIM.123890 2q33

Wednesday 14 April 2004

CD152, cytotoxic T lymphocyte-associated 4; CTLA-4

WKPD

Definition: CTLA4 is a member of the immunoglobulin superfamily and is a costimulatory molecule expressed by activated T cells.

CTLA4 or CTLA-4 (cytotoxic T-lymphocyte-associated protein 4), also known as CD152 (cluster of differentiation 152), is a protein receptor that, functioning as an immune checkpoint, downregulates immune responses.

CTLA4 is constitutively expressed in Treg cells but only upregulated in conventional T cells after activation. It acts as an "off" switch when bound to CD80 or CD86 on the surface of antigen-presenting cells.

The CTLA-4 protein is encoded by the Ctla4 gene in mice[6] and the CTLA4 gene in humans.[7]

Functions

- CTLA4 is similar to the T-cell costimulatory CD28, and both molecules bind to CD80 (MIM.112203) and CD86 (MIM.601020) on antigen-presenting cells.

- CTLA4 transmits an inhibitory signal to T cells, whereas CD28 transmits a stimulatory signal.

Pathology

- cytotoxic T lymphocyte antigen-4 (CTLA-4) gene is an important susceptibility locus for autoimmune endocrinopathies and other autoimmune disorders:

Targeted therapy

- anti-CTLA4s / CTLA-4 blockade

  • ipilimumab
  • tremelimumab

References

- Grohmann U, Puccetti P. CTLA-4, T helper lymphocytes and dendritic cells: an internal perspective of T-cell homeostasis. Trends Mol Med. 2003 Apr;9(4):133-5. PMID: 12727137

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