Expression of H v 1 proton channels in myeloid-derived suppressor cells (MDSC) and its potential role in T cell regulation.

SignificanceImmunosuppression by myeloid-derived suppressor cells (MDSC), especially near tumor surfaces, involves the extracellular production of reactive oxygen species (ROS). ROS generation in MDSC occurs during the oxidation of NADPH to NADP+, which NOX2 catalyzes. ROS react with the T cell receptor complex, abolishing the antigen presentation, which blocks the immune system elimination of the tumor cells. Extrusion of protons from MDSC by voltage-gated proton channel (Hv 1) sustains ROS production. Here, we demonstrate the expression of Hv 1 in mouse MDSC. In this way, Hv 1 present in MDSC becomes a potential cancer therapeutic target since its inhibition seems to diminish immunosuppression activity in the tumoral microenvironment, allowing cancer cells to be attacked by the immune system.