MDSCs exposed to CSC conditioned media promote immune suppression. Schematic (A) depicting the coculture strategy employed to determine the effect of MDSCs exposed to CSCs and NSTC conditioned media on T cell function. The ratio of CD4+ to CD8+ cells (B) was altered by MDSCs exposed to CSC conditioned media compared with NSTC conditioned media. The activation of T cells as reported by interferon-γ (IFNγ) expression (C) was suppressed when MDSCs were exposed to CSC conditioned media compared with NSTC conditioned media. Values shown are means ±standard deviation, *, p <.05, **, p <.01, and ***, p <.001 by one-way ANOVA. Activated T cells and neutrophils were used as controls. Abbreviations: CSC, cancer stem cell; MDSCs, Myeloid-derived suppressor cells; NSTC, Nonstem tumor cell.