Simplified assay for enrichment of primed human Th17 and Tc17 lymphocytes from peripheral blood

Background Interleukin-17A (IL-17A) is a potent pro-inflammatory cytokine that has been implicated in the pathogenesis of various autoimmune diseases. The production of IL-17A is commonly associated with subsets of CD4+ T cells (Th17) and CD8+ T cells (Tc17). Identifying these subsets based on intracellular expression of IL-17 or transcription factor RORC precludes isolation of viable Th17 and Tc17 cells and there by limits studies involving cell-cell interaction or cellular functions. Therefore, identifying surface markers that can help in identifying and enriching these cells is important. Results We used MCAM as a surrogate marker to identify in vivo committed human Th17 and Tc17 subsets. By employing high-speed fluorescence activated cell sorting, we enriched IL-17A-producing subsets from human specimens without the need for in vitro polarization using exogenous cytokines. These subsets can be investigated, following sorting, using a variety of methods such as ELISA, ex vivo functional assays and next generation sequencing to gain insights into the role of human Th17 and Tc17 in health and disease. Conclusion We here demonstrate that both CD4+ T cells (Th17) and CD8+ T cells (Tc17) cell populations can be identified based on the surface expression of melanoma cell adhesion molecule (MCAM or CD146). Keywords: MCAM, CD146, Th17, Tc17, Flow cytometry