Mitogenic and non-mitogenic ligands trigger a calcium-dependent cytosolic acidification in human T lymphocytes |
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Authors: | R K Cheung S Grinstein E W Gelfand |
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Affiliation: | Division of Immunology and Rheumatology, Hospital for Sick Children, Toronto, Canada. |
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Abstract: | 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. |
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