Myeloid-derived suppressor cells modulate B-cell responses

•Myeloid-derived suppressor cells (MDSCs) are important mediators of the immune cells.•MDSCs impair B-cell proliferation and induce B-cell death.•MDSCs decrease B-cell IgM responses and down regulate the expression of important ctivation surface markers.•MDSCs use of reactive oxygen species (ROS), arginase-1, and nitric oxide (NO) to modulate B-cell immune responses.

Myeloid-derived suppressor cells (MDSCs) are key regulators of adaptive immunity by suppressing T-cell functions. However, their potential action on or interaction with B cells remained poorly understood. Here we demonstrate that human polymorphonuclear MDSCs differentially modulate B-cell function by suppressing B-cell proliferation and antibody production. We further demonstrate that this MDSC-mediated effect is cell contact dependent and involves established mediators such as arginase-1, nitric oxide (NO), reactive oxygen species (ROS) as well as B-cell death. Collectively, our studies provide novel evidence that human MDSCs modulate B cells, which could have future implications for immunotherapy approaches.