[CTLA-4 is an inhibitory T-cell surface receptor for B7 ligands on antigen presenting cells. It contains an extracellular V-like domain, a transmembrane region, and a putative cytoplasmic domain. It shares significant homology with CD28. Both bind the same ligands, however CTLA-4 binds to B7 with a greater affinity. B7 antigen-presenting cells regulate T-cell activation by delivering antigen-independent stimulatory signals through CD28 and inhibitory signals through CTLA-4. While CD28 is on the membrane of resting T-cells, CTLA-4 is detectable only on cells activated after antigen presentation. A CTLA-4 splice variant with a deleted transmembrane segment is preferentially expressed in non-activated T-cells. Activation of lymphocytes results in the disappearance of sCTLA-4 followed by its gradual reappearance, whereas CTLA-4 increases after activation. CTLA-4 may play an inhibitory role in regulating lymphocyte expansion. (from OMIM 123890 and NCI) ( NCI )]
UMLS (NCI) C0111208 - Amino Acid, Peptide, or Protein
- Immunologic Factor
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