Inhibition by SK&F 96365 of Ca2+ current, IL‐2 production and activation in T lymphocytes

Abstract
1 By use of whole cell patch‐clamp and Indo‐1 fluorescence studies of the Jurkat T leukaemic cell line, we show that the new organic antagonist of receptor‐mediated Ca2+ entry, SK&F 96365, inhibits the T cell Ca2+ current in a dose‐dependent fashion, with an IC50 of 12 μm. 2 SK&F 96365 also inhibits [3H]‐thymidine incorporation and interleukin‐2 (IL‐2) synthesis in peripheral blood lymphocytes. 3 SK&F 96365 has no effect on Ca2+ stores release or K+ channels. 4 This is the first account of an organic inhibitor of the T cell Ca2+ current. The ability of SK&F 96365 to inhibit IL‐2 synthesis and cell proliferation suggests that a new class of related Ca2+ channel blockers can be developed as immunosuppressive agents.