TABLE 3.

Isotype distribution of memory B cells in circulation detected by flow cytometry, compared with isotype distribution of ASCs detected by ELISPOT assay after 3 and 6 days of in vitro stimulation (n = 7)

Cell typeStudy dayNo. of cells per million PBMCs (mean ± SD)Mean % ± SD
IgA+IgG+IgM+
CD19+CD27+ memory B cells prior to stimulation, by FACS analysisa220,000 ± 14,00021 ± 1045 ± 834 ± 14
3019,000 ± 14,00025 ± 941 ± 833 ± 9
ASCs after 3 days of stimulated culture, by ELISPOT assay27,200 ± 5,90032 ± 2046 ± 2223 ± 15
306,500 ± 6,90025 ± 1642 ± 1733 ± 17
ASCs after 6 days of stimulated culture, by ELISPOT assay243,000 ± 37,00018 ± 853 ± 1529 ± 11
3090,000 ± 86,00013 ± 848 ± 1139 ± 15
  • a FACS, fluorescence-activated cell sorter.