Calcium Signals in Helper T Cells after Interaction with Antigen-Specific and Antigen-Nonspecific B Cells

抄録

By confocal fluorescence microscopy we have studied the rises of the intracellular free calcium ion concentration ([Ca²⁺]_i) in helper T cells (KLH-specific, I-A^k-restricted Th1 cells, 28-4) after interaction with antigen-specific and antigen-nonspecific B cells (antigen-presenting cells). Antigen-specific and antigen-nonspecific B cells were prepared by the preincubation of TNP (trinitrophenol)-specific B cell hybridomas (TP67.21 I-A^k) with TNP-conjugated KLH and KLH alone, respectively. Calcium signals in Th1 cells (28-4) were induced by antigen-specific B cells one hundred times more efficiently as those by antigen-nonspecific B cells. Herbimycin A, a tyrosine kinase inhibitor, suppressed the former signals but not the latter. These results indicated that tyrosine phosphorylation was involved in the antigen processing of antigen-specific B cells but not in the processing of antigen-nonspecific B cells.