B7-CD28 superfamily receptors (B7-CD28 family)

The B7-CD28 superfamily receptors are a group of cell surface proteins on T cells that play a pivotal role in regulating immune responses through interactions with B7-family ligands on antigen-presenting cells, such as monocytes and dendritic cells (Sharpe & Freeman, 2002). This family includes costimulatory receptors like CD28 and ICOS, which provide essential signals for T cell activation, proliferation, and survival, as well as coinhibitory receptors like CTLA-4 and PD-1, which function as immune checkpoints to maintain self-tolerance and prevent excessive inflammation (UniProt). The balance between these positive and negative signals is critical for immune homeostasis; however, this balance is frequently subverted in diseases (Janeway's Immunobiology). In oncology, many tumors upregulate coinhibitory ligands like PD-L1 to suppress T cell-mediated immunity, while in autoimmune disorders, dysregulated costimulation can lead to tissue destruction (NCI). Therapeutic strategies targeting this superfamily include checkpoint inhibitors (e.g., pembrolizumab, ipilimumab) that block inhibitory signals to treat cancer, and costimulation blockers (e.g., abatacept) that inhibit T cell activation to treat autoimmune diseases and prevent transplant rejection (StatPearls).

Other names

B7-CD28 familyCD28 family receptorsB7-CD28 axisT-cell costimulatory receptorsB7-CD28 superfamilyB7-CD28 pathway

Modulation of T cell activation by either blocking coinhibitory 'checkpoint' receptors (e.g., CTLA-4, PD-1) or their ligands (e.g., PD-L1) to restore and enhance anti-tumor immunity, or by blocking costimulatory ligands (e.g., CD80/86) using decoy receptors (e.g., CTLA-4-Ig) to suppress T cell activation in autoimmune diseases and organ transplantation.