ABflo® 450 Rabbit anti-Human CD152/CTLA-4 mAb,ABclonal,A26550

Cytotoxic T-lymphocyte protein 4 (CTLA-4, CD152) is a member of the immunoglobulin superfamily that negatively regulates early T-cell activation. This protein is primarily expressed on T cells, including CD8+ cytotoxic T cells, CD4+ helper T cells, and CD4+/FoxP3+ regulatory T cells (Tregs). On the cell surface, CTLA-4 competes with CD28 for binding to the ligands B7.1 (CD80) and B7.2 (CD86), thereby downregulating T-cell activity. The subsequent activation of downstream effectors SHP-2 and PP2A attenuates TCR signaling. Studies have shown that CTLA-4 gene knockout mice develop severe lymphoproliferative disorders and die at an early age, confirming the essential role of CTLA-4 as a negative regulator of T cells. Correspondingly, mutations in the CTLA4 gene are associated with various autoimmune and immune dysregulation syndromes, including insulin-dependent diabetes mellitus, Graves' disease, Hashimoto's thyroiditis, celiac disease, systemic lupus erythematosus, and autoimmune lymphoproliferative syndrome type V. Further research has established that blockade of the CTLA-4 pathway represents an effective strategy in cancer immunotherapy.