Introduction of Camrelizumab

Camrelizumab (INCSHR-1210, SHR-1210) is an IgG4κ humanized monoclonal antibody (mAb) being investigated for hepatocellular carcinoma. It targets programmed cell death protein 1 (PD-1), a protein on the surface of cells, also known as CD279 (cluster of differentiation 279).

Mechanism of Action of Camrelizumab

PD-1 is a cell surface receptor that belongs to the immunoglobulin superfamily and is expressed on T cells and pro-B cells. PD-1 binds two ligands, programmed death-ligand 1 (PD-L1) and programmed death-ligand 2 (PD-L2). PD-L1 is also known as cluster of differentiation 274 (CD274) or B7 homolog 1 (B7-H1), and PD-L2 is also known as cluster of differentiation 273 (CD273). PD-1 is an immune checkpoint and has a role in regulating the immune system's response by down-regulating the immune system and promoting self-tolerance by suppressing T cell inflammatory activity. Physiologically, the PD-1/PD-L1 pathway has emerged as a result of the need to control the degree of inflammation at locations expressing the antigen, in order to secure normal tissue from damage. There is a remarkable expression of the PD-1 protein on the surface of all activated T cells. When a T cell recognizes the antigen expressed by the major histocompatibility complex (MHC) on the target cell, inflammatory cytokines are produced, initiating the inflammatory process. These cytokines result in PD-L1 expression in the tissue, activating the PD-1 protein on the T cell leading to immune tolerance, a phenomenon where the immune system lose the control to mount an inflammatory response, even in the presence of actionable antigens. In certain tumors, most remarkably in melanomas, this protective mechanism is perverted through overexpression of PD-L1; as a result, it circumvents the generation of an immune response to the tumor. PD-1/PD-L1 inhibitors, including camrelizumab, pharmacologically prevent the PD-1/PD-L1 interaction, thus facilitating a positive immune response to kill the tumor.

Fig.1 Mechanism of action of camrelizumab

For research use only. Not intended for any clinical use.