B7

The B7 family constitutes a pivotal group of co-signaling molecules in immune regulation, encompassing members such as B7-1 (CD80), B7-2 (CD86), B7-H1 (PD-L1), B7-DC (PD-L2), B7-H3 (CD276), B7-H4 (VTCN1), B7-H5 (HHLA2), B7-H6, and B7-H7. These molecules mediate activation or inhibitory signals by binding to CD28/CTLA-4, PD-1, or undefined receptors, thereby regulating T cell activation, proliferation, and immune tolerance. The B7 family plays a critical role in infection, autoimmunity, and tumor immune evasion, and has emerged as a significant therapeutic target for immune checkpoint inhibitors, CAR-T therapies, and bispecific antibodies.