RESUMEN
Myeloid-derived suppressor cells (MDSC) are a heterogeneous population of immature myeloid cells that are generated from the blockade differentiation of myeloid cells during pathological conditions. MDSC are regulatory immune cells with a potent immunosuppressive function, and play an important role in the development of various diseases including tumor, autoimmune diseases and trauma. Interestingly, emerging evidence shows that respiratory tract infections by viruses, bacteria and fungi can cause MDSC expansion and activation. MDSC levels are closely related to the symptoms of diseases caused by respiratory pathogens. Further investigation on the role and molecular mechanism of MDSC expansion and activation in respiratory tract infections will contribute to the development of novel strategies for the prevention and treatment of diseases caused by respiratory pathogens. Here, we summarized the role of MDSC in respiratory viral, bacterial and fungal infections and the relevant molecular mechanisms, aiming to provide a reference for further investigating the role of MDSC in respiratory tract infections.