Heterogeneity among T Cells in Intracellular Free Calcium Responses after Mitogen Stimulation with PHA or Anti-CD3. Simultaneous Use of Indo-1 and Immunofluorescence with Flow Cytometry

摘要

Measurement of intracellular ionized calcium concentrations (Ca(2=)i) has been indispensable in elucidating the central role of Ca(2+)i as a trigger of cellular responses to activating stimuli. Such studies have employed the dye quin2, which has not been readily adapted to analysis of individual small cells. The calcium response of large numbers of single cells can be analyzed with the use of flow cytometry and the recently described dye, indo-1. Such analyses demonstrate for the first time the heterogeneous nature of the Ca(2+)i response to mitogenic stimuli within populations of peripheral blood lymphocytes (PBL). By stimultaneous quantitation of one- or two-color surface immunofluorescence lables, some of this heterogeneity of Ca(2+)i response in PBL is shown to be related to cellular immunophenotype. Almost all T cells responded to anti-CD3 antibody. The response is greater among CD4(+) than CD8(+) cells, and within the CD4(+) population the rate of response to stimulation by antibody to CD3 differed between subpopulations defined by expression of the common leukocyte marker p220. Not all T cells responded to phytohemagglutinin (PHA), even at very high doses. As with anti-CD3, after stimulation with PHA, CD4(+) cells showed a larger proportion of responding cells than did CD8(+) cells.