Isolation of Human Circulating Myeloid-Derived Suppressor Cells and Analysis of Their Immunosuppressive Activity

Myeloid-derived suppressor cells (MDSC) are a heterogeneous population of myeloid cells with potent immunosuppressive activity and characterized by a pathological state of activation. The T cell suppression assay is the most common method to evaluate the suppressive capacity of MDSC. Identifying the suppressive potential of different MDSC subsets within individual donors is key for understanding the biology of MDSC and their clinical relevance. Here we describe assays to ascertain and quantify the suppression of autologous T cells by human MDSC. These include the dye dilution proliferation assay for flow cytometry and the detection of IFNγ production by T cells using flow cytometry and sandwich ELISA.