title: Extracellular acidic pH modulates oxygen-dependent cytotoxic responses mediated by polymorphonuclear leucocytes and monocytes.
abstract: In the present study, we compared the ability of human neutrophils and monocytes to display oxygen-dependent cytotoxic responses at pH 7.4 and 6.2. Our results show that cytotoxicity induced by immune complexes (IC), zymosan, N-formyl-methionyl-leucyl-phenylalanine (FMLP) and concanavalin A (Con A) were markedly increased when they were carried out at pH 6.2 instead of pH 7.4. Cytotoxicity induced by phorbol myristate acetate (PMA), on the contrary, was significantly decreased at pH 6.2. It is noteworthy that cytotoxic responses induced by IC, zymosan and Con A were also increased when, 2 h after effector cell stimulation at pH 6.2, cytotoxicity was measured at pH 7.4. Finally, when we examined possible mechanisms involved in the augmentation of cytotoxicity, we observed that the oxidative response of IC-stimulated neutrophils, measured as chemiluminescence emission, was not increased at pH 6.2, on the contrary, it was significantly decreased. The relevance of these results is discussed.
authors.affiliation: Instituto de Investigaciones Hematológicas (IIHEMA), Academia Nacional de Medicina, Buenos Aires, Argentina.
authors.forename: J R
authors.initials: JR
authors.lastname: Geffner
authors.forename: A S
authors.initials: AS
authors.lastname: Trevani
authors.forename: F
authors.initials: F
authors.lastname: Minnucci
authors.forename: M S
authors.initials: MS
authors.lastname: Palermo
authors.forename: N
authors.initials: N
authors.lastname: Maugeri
authors.forename: M A
authors.initials: MA
authors.lastname: Isturiz
mesh_terms: D000936:Antigen-Antibody Complex / Q000276:immunology; D002478:Cells, Cultured; D003602:Cytotoxicity, Immunologic; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008163:Luminescent Measurements; D009000:Monocytes / Q000276:immunology*; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000276:immunology*; D010100:Oxygen / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D000936:Antigen-Antibody Complex; D009240:N-Formylmethionine Leucyl-Phenylalanine; D013755:Tetradecanoylphorbol Acetate; D010100:Oxygen