B7 family member (B7)

The **B7 family** comprises a group of structurally related, cell-surface protein ligands, primarily expressed on antigen-presenting cells, that interact with receptors on lymphocytes to regulate immune responses[1][2][4][5]. B7 molecules deliver essential secondary signals required for T cell activation, functioning as both **co-stimulatory (activating)** and **co-inhibitory (suppressing)** molecules, thereby maintaining immune homeostasis and contributing to immune tolerance and activation[1][2][3][6]. The canonical members include B7-1 (CD80), B7-2 (CD86), B7-H1 (PD-L1), B7-H2 (ICOS ligand), B7-H3, B7-H4, PD-L2 (B7-DC), and B7-H6[5][6][2]. While the **term "B7 family molecules" refers to a group, not a single molecule or direct drug target**, individual members such as PD-L1 or CD80 are highly regarded as therapeutic targets in cancer immunotherapy, contributing crucially to immune checkpoint pathways[5][6][2][4][1]. Therapeutic manipulation of B7 signaling (notably PD-L1 and CD80/CD86) underpins several immunotherapies for cancer, autoimmunity, and transplantation; drugs in this class are associated with immune-related toxicities due to systemic modulation of immune checkpoints[2][6][4]. **Note:** The term "B7 family molecules" is plural and non-specific; it describes a molecular family, not a single actionable target. For structured data or therapeutic purposes, specify individual family members (e.g., "Programmed cell death ligand 1 (PD-L1)" or "CD80") for precise, actionable information.

Other names

B7 family moleculesB7 ligandsB7 superfamilyCo-stimulatory/co-inhibitory moleculesB7-1 (CD80)B7-2 (CD86)B7-H1 (PD-L1 or CD274)B7-H2 (ICOS ligand or CD275)B7-H3 (CD276)B7-H4 (B7x, B7S1)B7-DC (PD-L2 or CD273)B7-H6

Immune checkpoint blockade: Drugs bind to B7 ligands or their receptors (e.g., PD-1, CTLA-4) and block co-inhibitory signaling, promoting T cell activity against tumors and other targets