A developmental mechanism in which certain cells die, usually by apoptosis, as a programmed morphogenetic shaping mechanism, e.g. separating digits of the developing hand and foot. Programmed death-1 (PD-1, 288 aa) is an inhibitory receptor of the B7 family on T cells that causes immune dysfunction when it is up-regulated, as happens in HIV infection. A polymorphism in a regulatory region is associated with susceptibility to systemic lupus erythematosus. The ligands are themselves membrane proteins, homologues of B7, (B7H1, 290 aa; PDL2, 182 aa) and members of the immunoglobulin superfamily, but do not bind to CTLA4 or CD28. Programmed cell death 10 (PCD10, 212 aa) is defective in cerebral cavernous malformations type 3 and seems to be involved in vascular morphogenesis.
Subjects: Medicine and Health.