程序性死亡分子1（programmed death-1，PD-1）及其配体（programmed death-1 ligand，PD-L）是一对新近研究较多的负性共刺激分子。PD-1与其配体结合后，传导的信号能抑制T淋巴细胞增殖，在调节T细胞活化和免疫耐受过程中发挥关键作用，从而对防止自身免疫病的发生、发展具有重要作用。PD-1/PD-L在免疫调节中的作用使其有望成为治疗免疫性疾病新的靶向分子。

Programmed death-1 (PD-1) and its ligands (PD-L) are a pair of co-inhibitory molecules popularly studied recently. The signal transduced via PD-1 after binding its ligands acts on regulation of T-cell activity and maintenance of peripheral tolerance by suppressing T-cell proliferation. Therefore, PD-1 plays an important role in preventing onset and progression of autoimmune diseases. The role of PD-1/PD-L in immune regulation makes them new target molecules in the treatment of autoimmune diseases.