FACS analysis of the purified memory population. Whole tonsillar
lymphocytes were depleted of IgD+ naive B cells and CD3+ T cells by
MACS. The depletions were 99% efficient. The resulting population was
stained for CD10 and IgD expression, and the memory B cells (IgD−,
CD10−) were separated from the germinal center B cells (IgD−, CD10+)
by FACS. (A) Unfractionated tonsil cells stained with
FITC anti-CD20 (a pan-B cell marker) and PE-coupled anti-IgD.
(B) FACS reanalysis of the purified populations with
FITC anti-CD10 and PE-coupled anti-IgD (Left) or FITC
anti-CD20 and PE-coupled anti-CD10 (Right). Note that the
purified population is 95% pure B cells, based on restaining for CD20,
and contains only 0.1% IgD+ (naive) and 0.5–0.8% CD10+ (germinal
center) B cells.