Receptor-mediated calcium signal playing a nuclear third messenger in the activation of antigen-specific B cells.
We have studied receptor-mediated calcium signals in antigen-specific B cells (trinitrophenol-specific B cell clone, TP67.21) using a confocal fluorescence microscope with an argon ion laser (488 nm) and a He-Cd laser (325 nm). Confocal fluorescence images of fluo-3 loaded B cells, excited by an argon ion laser, became much brighter and more nonhomogeneous than those before antigen stimulation. Time-dependent fluorescence changes in intensities were abrupt and quite similar to the patterns of the intracellular calcium ion concentration [Ca2+]i observed by a conventional fluorescence microscope using fura-2. From the morphological patterns of the calcium images, the parts of the bright fluorescence seemed to belong to the nucleus in B cells. To confirm the above events we measured the confocal fluorescence images of the nucleus. From the fluorescence images of co-loaded Hoechst 33342 (a DNA-specific fluorescent probe), which excited by a He-Cd laser, the brighter parts of the fluo-3 fluorescence intensities were identified to the nucleus in B cells. This suggested the possibility that the increased intranuclear calcium ions may play a nuclear third messenger in B cells.
Faculty of Pharmaceutical Sciences, Nagoya City University, Japan.
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Furuno
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Hamano
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Nakanishi
D000818:Animals; D000941:Antigens; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism*; D055592:Biophysical Phenomena; D001703:Biophysics; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D005456:Fluorescent Dyes; D008213:Lymphocyte Activation; D008856:Microscopy, Fluorescence; D011956:Receptors, Cell Surface / Q000276:immunology / Q000378:metabolism*; D015398:Signal Transduction; D014301:Trinitrobenzenes / Q000276:immunology
D000941:Antigens; D005456:Fluorescent Dyes; D011956:Receptors, Cell Surface; D014301:Trinitrobenzenes; D002118:Calcium