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Clinical and Diagnostic Laboratory Immunology, 01 1997, 70-74, Vol 4, No. 1
L Gergely, L Cook and V Agnello
A method for Ca2+ flux measurement on isolated human peripheral B cells
that uses flow cytometry is described. B cells were isolated by anti- CD19
magnetic bead sorting, and Ca2+ flux was measured with the fluo-3 reagent
on a standard single-laser flow cytometer. The response of B- cell
stimulation by anti-immunoglobulin B (anti-IgM), anti-IgD, protein A,
concanavalin A, and ionomycin was determined. Percentage of responder B
cells, the level of Ca2+, and the time of peak stimulation were measured.
Bound anti-CD19 monoclonal antibody coupled with small paramagnetic
particles did not affect Ca2+ flux. All the isolated B cells responded
maximally at 10s with stimulation by 8 microg of ionomycin. The average
isolated preparation contains 70% IgM+ and 85% IgD+ cells, all of which
showed peak stimulation with 10 microg of anti- IgM and anti-IgD per ml,
respectively, at 30s. Only at high concentrations of 80 microg/ml,
concanavalin A produced a slower response, peaking at 90 s after
stimulation. Stimulation with 20 microg of protein A per ml resulted in
Ca2+ flux in only 40 to 60% of cells that had a rapid response and maximal
stimulation resembling the pattern of activation of ionomycin. B cells from
three patients with mixed cryoglobulinemia with high concentrations of
monoclonal rheumatoid factors showed stimulation with aggregated IgG,
whereas those from healthy control subjects did not, demonstrating the
applicability of the methodology to detection of specific antigen
stimulation of B cells. This methodology may be useful in testing the
functional capacity of B cells in a variety of diseases. The methodology
may also prove useful in studying antigen-specific B-cell responses when
they involve a significant percentage of B cells.
Copyright © 1997 by the American Society for Microbiology. All rights reserved.
A simplified method for Ca2+ flux measurement on isolated human B cells that uses flow cytometry
Department of Laboratory Medicine, Lahey Hitchcock Medical Center, Burlington, Massachusetts 01805, USA.
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