Description: Inhibitory receptor acting as a major negative regulator of T-cell responses. The affinity of CTLA4 for its natural B7 family ligands, CD80 and CD86, is considerably stronger than the affinity of their cognate stimulatory coreceptor CD28. (www.uniprot.org) Produced in insect cells as a homodimeric, glycosylated, polypeptide chain.