Fine regulation of neutrophil function by extracellular pH

ERRA DIAZ F; DANTAS E; MARU A; CABRERA M; MERLOTI A; VARESE A; RUBIONE J; DUETTE G; TREVANI AS; GEFFNER JR

Congreso; II Congreso Franco-Argentino de Inmunología.; 2015

Background: Inflammatory processes are usually characterized by low values of extracellular pH, however, few studies have addressed the influence of extracellular pH on the immune response. We have previously shown that exposure of neutrophils to pH 6.5 results in neutrophil activation (shape change, induction of Ca2+ transients and up-regulation of CD11b expression) and a modest delay in apoptosis. We here compared the neutrophil pattern responses induced by pH 6.5 vs pH 6.0. Methods: Human neutrophils were isolated by conventional methods. We compared the effects induced by pH 6.5 and pH 6.0 on: a) rate of apoptosis (annexin V/propidium iodide staining and flow cytometry), production of IL-8 (ELISA), release of myeloperoxidase (MPO) (ELISA), and production of oxygen reactive intermediates (oxidation of dihidrorodamine and flow cytometry). Results: We found marked differences in all the parameters analyzed, when the responses induced by pH 6.5 and pH 6.0 were compared. The anti-apoptotic effect was markedly higher at pH 6.0 compared with pH 6.5 (p