Mitogenic and non-mitogenic ligands trigger a calcium-dependent cytosolic acidification in human T lymphocytes.
We have investigated the patterns of cytosolic pH and Ca2+ ([Ca2+]i) changes after exposure of human peripheral blood T cells to different mitogenic and non-mitogenic ligands. Using ligands that have different accessory cell requirements and varying effect on [Ca2+]i or cell proliferation, we observed that intracellular acidification occurred only with agents that increased [Ca2+]i. However, treatment of the cells with the phorbol ester, 12-O-tetradecanoylphorbol-13-acetate, results in significant cytosolic alkalinization without detectable acidification, but did not affect the proliferative responses to mitogenic ligands and was a potent co-mitogen with non-mitogenic ligands. These data indicate that initial acidification or alkalinization responses are not essential for early activation or triggering of DNA synthesis.
Cheung
R K
RK
Division of Immunology and Rheumatology, Hospital for Sick Children, Toronto, Canada.
Grinstein
S
S
Gelfand
E W
EW
D000911:Antibodies, Monoclonal / Q000502:physiology; D002118:Calcium / Q000502:physiology*; D003208:Concanavalin A / Q000494:pharmacology; D003600:Cytosol / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D037102:Lectins / Q000494:pharmacology*; D008213:Lymphocyte Activation / Q000187:drug effects*; D010703:Phorbol Esters / Q000494:pharmacology; D010835:Phytohemagglutinins / Q000494:pharmacology; D013205:Staphylococcal Protein A / Q000494:pharmacology; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D014909:Wheat Germ Agglutinins / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D037102:Lectins; D010703:Phorbol Esters; D010835:Phytohemagglutinins; D013205:Staphylococcal Protein A; D014909:Wheat Germ Agglutinins; D003208:Concanavalin A; D002118:Calcium