Human BTLA/CD272 protein, ECD (extracellular domain), recombinant

Description :
CD272, also known as BTLA (B- and T-lymphocyte attenuator), is a single pass type I transmembrane glycoprotein that belongs to the CD28/CTLA4 family of the Ig superfamily. Like CD28 and CTLA4, CD272 contains one Ig-like domain in the extracellular region. However, the Ig-like domain is an I­type rather than a V­type domain commonly found in other family members. CD272 also differs from other CD28/CTLA4 family members through the interaction of its Ig-like domain with the TNF superfamily member, HVEM (TNFRSF14) rather than with B7 family ligands. CD272 is an immune co-inhibitory molecule expressed on T cells, B cells and, macrophages, dendritic and NK cells. The HVEM-CD272 ligation relays inhibitory signals to suppress the immune response. Expression of CD272 is low in naïve T cells and increased during antigen­specific induction of anergy. In B cells, BTLA is highest when cells are mature and naïve. BTLA appears to limit T cell numbers, since deletion of BTLA results in overproduction of T cells, especially CD8+ memory T cells in mice. There are two ITIM motifs and three Tyr phosphorylation sites in the cytoplasmic tail of CD272 that mediate inhibitory signaling. Polymorphisms in the CD272 gene have been associated with an increased risk of rheumatoid arthritis.