Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and Cluster of Differentiation 80 (CD80) interaction (CTLA-4/CD80)

The interaction between Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and Cluster of Differentiation 80 (CD80) serves as a fundamental inhibitory checkpoint in the regulation of T-cell-mediated immune responses (UniProt P16410, P33681). CTLA-4 is upregulated on T cells following activation and competes with the costimulatory receptor CD28 for binding to CD80 (also known as B7-1) on antigen-presenting cells. Because CTLA-4 possesses a significantly higher affinity for CD80 than CD28, it effectively outcompetes the activating signal, leading to the suppression of T-cell proliferation and cytokine production (StatPearls, "Physiology, T-Cell Receptor"). This mechanism is essential for maintaining peripheral tolerance and preventing autoimmunity, but it is often co-opted by tumors to escape immune surveillance. Therapeutic strategies targeting this interaction include monoclonal antibodies like ipilimumab, which block CTLA-4 to unleash an anti-tumor immune response, and CTLA-4-Ig fusion proteins like abatacept, which mimic the inhibitory signal to treat autoimmune diseases such as rheumatoid arthritis (PubMed PMC4408251). This dual-natured target remains a cornerstone of both modern immuno-oncology and clinical rheumatology.

Other names

CTLA-4/B7-1 interactionCD152/CD80 interactionCTLA4-CD80 complexCTLA4-B7 interaction

Therapeutic modulation involves either blocking the CTLA-4 receptor with monoclonal antibodies to prevent its inhibitory signal and enhance T-cell activity against cancer cells, or utilizing CTLA-4-Ig fusion proteins to bind and sequester CD80/CD86 ligands, thereby preventing CD28-mediated costimulation and suppressing autoimmune responses.