Concanavalin A induces Ca2+ mobilization, but only minimal inositol phospholipid breakdown in mouse B cells.
Concanavalin A (Con A) induces DNA synthesis in bulk cultures of murine T cells. In contrast, the lectin has been shown to stimulate purified B cells to leave G0, but not to proliferate. We demonstrate here that Con A induces comparable increases in intracellular Ca2+ levels in the two cell types. In B cells this appears to be due to Ca2+ influx. As expected, the lectin also provokes significant degradation of inositol phospholipids in T cells. However, it causes only minimal release of inositol phosphates in B cells. We therefore postulate that Con A may stimulate B cells by causing influx of Ca2+. In line with this, activation of B cells by the lectin is inhibited by cyclosporine, which preferentially affects stimulation of lymphocytes by Ca2+ mobilizing agents.
D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000502:physiology; D001402:B-Lymphocytes / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D003208:Concanavalin A / Q000494:pharmacology*; D007295:Inositol Phosphates / Q000378:metabolism; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D010716:Phosphatidylinositols / Q000378:metabolism*; D013601:T-Lymphocytes / Q000378:metabolism
D000888:Antibodies, Anti-Idiotypic; D007295:Inositol Phosphates; D010716:Phosphatidylinositols; D003208:Concanavalin A; D002118:Calcium