Structure of PD1 and its mechanism in the treatment of autoimmune diseases

Abstract PD‐1 and CTLA‐4 can play an important role in addressing the issue of autoimmune diseases. PD‐1 is a transmembrane glycoprotein expressed on T, B, and Dentric cells. This molecule functions as a checkpoint in T cell proliferation. Ligation of PD‐1 with its ligands inhibits the production of IL‐2, IL‐7, IL‐10, and IL‐12 as well as other cytokines by macrophages, natural killer (NK) cells, and T cells, which can suppress cell proliferation and inflammation. Today, scientists attempt to protect against autoimmune diseases by PD‐1 inhibitory signals. In this review, we discuss the structure, expression, and signaling pathway of PD‐1. In addition, we discuss the importance of PD‐1 in regulating several autoimmune diseases, reflecting how manipulating this molecule can be an effective method in the immunotherapy of some autoimmune diseases.