CALCIUM SIGNALS IN HELPER T-CELLS AFTER INTERACTION WITH ANTIGEN-SPECIFIC AND ANTIGEN-NONSPECIFIC B-CELLS

By confocal fluorescence microscopy we have studied the rises of the i ntracellular free calcium ion concentration ([Ca2+](i)) in helper T ce lls (KLH-specific, I-A(k)-restricted Th1 cells, 28-4) after interactio n with antigen-specific and antigen-nonspecific B cells (antigen-prese nting tells), Antigen-specific and antigen-nonspecific B cells were pr epared by the preincubation of TNP (trinitrophenol)-specific B cell hy bridomas (TP67.21 I-A(k)) with TNP-conjugated KLH and KLH alone, respe ctively, Calcium signals in Thl cells (28-4) were induced by antigen-s pecific B cells one hundred times more efficiently as those by antigen -nonspecific B cells, Herbimycin A, a tyrosine kinase inhibitor, suppr essed the former signals but not the latter, These results indicated t hat tyrosine phosphorylation was involved td in the antigen processing of antigen-specific B cells but not in the processing of antigen-nons pecific B cells.