Figure 1. Myeloid Derived Suppressor Cells (MDSCs) and T-cell suppression.
MDSCs are immature myeloid cells originating in the bone marrow that are recruited to the tumor microenvironment through production of various tumor derived factors (TDFs). These chemokines and cytokines stimulate the production of myeloid precursors in the marrow, and facilitate their recruitment and accumulation within the tumor microenvironment. Once in tumor sites, MDSCs are potent suppressors of T-cells via a wide array of different mechanisms. Moreover, MDSCs in tumor sites can further differentiate into tumor associated macrophages (TAMs) and also into suppressive dendritic cells.