The Effect of Immunosuppressive Drugs on MDSCs in Transplantation

Figure 1

The development, subsets, and phenotypes of MDSCs. MDSCs arise from CMP in the presence of several growth factors and cytokines during emergency myelopoiesis under inflammatory conditions. Growth factors (signal 1) drive the expansion of myeloid cell progenitors. Subsequent activation signal (signal 2) via cytokines endows these progenitors with immunosuppressive function to give rise to e-MDSCs, M-MDSCs, and PMN-MDSCs. Recently, it was found that GMP and MDP yielded distinct monocyte-committed progenitors which differentiated into different monocyte subsets at steady-state, respectively. Which of the two monocyte-committed progenitors can give rise to functional M-MDSCs and further acquiring the ability to differentiate into PMN-MDSCs during emergency myelopoiesis is unclear. The phenotype markers of different MDSC subsets are illustrated here. CMP, common myeloid progenitor; GMP, granulocyte-monocyte progenitor; MDP, monocyte-dendritic cell progenitor; MP, monocyte-committed progenitor; cMoP, common monocyte progenitor; GP, granulocyte-committed progenitor; G-mono, GMP-derived monocyte; M-mono, MDP-derived monocyte.