herbimycin and picric-acid

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-Ak-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-Ak) 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.

Topics: Animals; Antigens; B-Lymphocytes; Benzoquinones; Calcium; Cell Line; Hemocyanins; Lactams, Macrocyclic; Lymphocyte Activation; Mice; Microscopy, Confocal; Picrates; Quinones; Receptors, Antigen, B-Cell; Receptors, Cell Surface; Rifabutin; Signal Transduction; T-Lymphocytes, Helper-Inducer