Filtered Products

Immune checkpoint proteins are a class of key membrane proteins located on the surface of immune cells or tumor cells that regulate the intensity of immune responses. By binding to their corresponding ligands or receptors, they transmit co-stimulatory (activating) or co-inhibitory (suppressing) signals to immune cells, thereby maintaining immune homeostasis and preventing autoimmune reactions. Among them, co-inhibitory checkpoint proteins represented by PD-1, PD-L1, and CTLA-4 normally act as the ""brakes"" of the immune system, ensuring that immune responses do not excessively damage healthy tissues.

However, tumor cells can exploit these immune checkpoint proteins to suppress T cell activity and achieve immune evasion, for instance by overexpressing PD-L1. To counter this mechanism, monoclonal antibody drugs targeting immune checkpoints (such as anti-PD-1, anti-PD-L1, and anti-CTLA-4 inhibitors) can block the transmission of inhibitory signals and reactivate the immune system to attack tumors. Currently, immune checkpoint inhibitors have become a cornerstone of cancer immunotherapy, demonstrating remarkable efficacy in the treatment of various malignancies, including melanoma, non-small cell lung cancer, and renal cell carcinoma. Furthermore, soluble immune checkpoint proteins, as biomarkers in serum, are also used to monitor immunotherapy responses and assess patient prognosis.