B And T-Lymphocyte Attenuator (BTLA)

BTLA expression is induced during activation of T cells, and BTLA remains expressed on Th1 cells but not Th2 cells. Like PD1 and CTLA4 , BTLA interacts with a B7 homolog, B7H4. However, unlike PD-1 and CTLA-4, BTLA displays T-Cell inhibition via interaction with tumor necrosis family (TNF) receptors, not just the B7 family of cell surface receptors.

BTLA is a ligand for tumour necrosis factor (ligand) superfamily, member 14 (TNFSF14), also known as herpes virus entry mediator (HVEM). BTLA-HVEM complexes negatively regulate T-cell immune responses.Northern blot analysis revealed expression in lymph node and spleen, as well as in polarized Th1 but not Th2 cells. Flow cytometric analysis demonstrated surface expression of a transmembrane protein.