The acidity of the tumor microenvironment is a mechanism of immune escape that can be overcome by proton pump inhibitors

We have recently reported that lowering the pH to values that are frequently detected in tumors causes reversible anergy in both human and mouse CD8(+) T lymphocytes in vitro. The same occurs in vivo, in the tumor microenvironment and the administration of proton pump inhibitors, which buffer tumor acidity, can revert T-cell anergy and increase the efficacy of immunotherapy.