CTLA4 is a member of the immunoglobulin superfamily and is a costimulatory molecule expressed by activated T cells.
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:
- insulin-dependent diabetes mellitus
- Graves hyperthyroidism (MIM.275000)
- Hashimoto thyroiditis (MIM.140300)
- celiac disease
- systemic lupus erythematosus (15138458)
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