19.12.2012, 17:15 - HZI-Kolloquium - Scientific
Manfred Lutz "Understanding Myeloid-Derived Suppressor Cell Functions: GM-CSF-Licensing and Mycobacterial Activation"
Myeloid-derived suppressor cells (MDSCs) are a heterogeneous subset of myeloid cells with an immature phenotype and T cell-suppressive functions. Under steady-state conditions they are lacking the suppressive activity and are called immature myeloid cells (IMCs). In the mouse two major subsets have been defined: granulocytic and monocytic MDSCs. However, the difference of the latter subset to monocytes has not been defined yet. Our data suggest that GM-CSF "licensing" of monocytes marks their conversion to IMC in order to respond to further LPS/IFN-γ activation. MDSC activation can also strongly be induced by mycobacteria. Our results indicate new survival and immune escape strategies by Mtb by hiding in caveolae of MDSC but simultaneously expand and activate them for immune suppression of T cell responses.