MDSC

"Regulatory myeloid immune cells, such as myeloid-derived suppressor cells (MDSCs), populate inflamed or cancerous tissue and block immune cell effector functions. These can be of monocytic (M-MDSCs) or polymorph nuclear origin (PMN-MDSCs)"32327756 ... todo

"the three MDSC subset clusters - granulocytic (G-), monocytic (M-), and early (E-) MDSCs. "...todo 33021571 "Progression from hematopoietic stem cells (HSC) to tumor-infiltrating myeloid cells. The formation of tumor-infiltrating myeloid cells occurs in a step-wise process: In the bone marrow, HSCs give rise to common myeloid progenitors (CMP), which give rise to granulocyte-monocyte progenitors (GMP). GMPs then further specify into myeloblasts (MB) and monocyte-dendritic cell progenitors (MDP). These precursors then differentiate into a range of different cell types with anti-tumorigenic (blue) and pro-tumorigenic (red) capacities. MDPs can give rise to a common dendritic cell progenitor (CDP), further leading to the formation of conventional DCs (cDCs) or plasmacytoid (pDCs). MDPs also form monocytes, giving rise to monocytic DCs (moDCs) or differentiating into tumor-associated macrophages (TAMS) upon instruction by the tumor. Macrophages can display multiple different activation states, ranging from anti-tumorigenic to pro-tumorigenic subsets. MBs give rise to mature neutrophils or polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs), while monocytic MDSCs (M-MDSCs) arise from MDPs upon instruction by inflammatory signals. All of these cell types are characterized by specific surface marker expression, indicated for both human and mouse cells." https://pubmed.ncbi.nlm.nih.gov/31849950/

https://www.frontiersin.org/articles/10.3389/fimmu.2019.02746/full

"granulocytic MDSCs (G-MDSCs), which have a CD11b+Ly6G+Ly6Clow phenotype, whilst monocytic MDSCs (M-MDSCs) have a CD11b+Ly6G−Ly6Chigh phenotype [2]. CD49d was suggested by Haile et al., 2010, to be an alternative marker for Gr-1 to differentiate G-MDSCs (CD11b+ CD49d−) and M-MDSCs (CD11b+ CD49d+). Additionally, M-MDSCs acquired the ability to differentiate into tumor-associated macrophages (TAMs), which produced immunosuppressive cytokines that protected the tumor from the immune system and immunotherapy. Human MDSC was firstly identified in hepatocellular carcinoma and non-Hodgkin’s lymphoma patients with phenotypes CD14+HLA-DRlow/− [9,10]. Other phenotypic markers for human MDSC subsets in the peripheral blood include CD11b+CD14–CD15+ or CD11b+CD14−CD66b+ for G-MDSC, CD11b+CD14+HLA-DR−/lowCD15− for M-MDSC, and Lin−HLA-DR−CD33+ for more immature MDSC progenitors "32443699 .. todo: extract table 1