Modulation of intracellular Cl- homeostasis by lectin-stimulation in Jurkat T lymphocytes

We investigated changes in intracellular Cl- concentration ([Cl-](i)) during lectin-induced activation and proliferation in human Jurkat T lymphocytes. [Cl-](i) was measured using Cl- fluorescence dye (N-(6-methoyquinolyl) acetoxy-acetyl-ester, MQAE) methods. Lectins, phytohemagglutinin and concanavalin A, dose-dependently increased [Cl-](i) and triggered intracellular Cl- oscillation in human Jurkat T lymphocytes. However, some mitochondria metabolism inhibitors, such as m-chlorocarbonylcyanide phenylhydrazone (CCP) and 2,4-dinitrophenol, increased [Cl-](i) without triggering any Cl- oscillation. Furthermore, both lectins and metabolism inhibitors-induced elevation in [Cl-](i) were blocked by removal of extracellular Cl- from perfusion solution or by application of anthracene-9-carboxylate, a blocker of Cl- channels. Since an extracellular Cl--free condition and application of 9-AC also inhibited PHA-induced proliferation, we suggested that elevation of [Cl-](i) via activation of Cl- channels and increase in incidence of Cl- oscillation would play an important role in modulation of Jurkat T cell activation and proliferation. (C) 2003 Elsevier B.V. All rights reserved.