Analysis of the specificity of IgM in supernatants from human B cells stimulated with OMV.

aAverage values of mean fluorescence intensity±SEM from three independent experiments with separate tonsil donors. Bacteria were incubated with supernatants from B cell cultures as indicated followed by incubation with FITC-conjugated rabbit anti-human IgM and flow cytometry analyses.
bThe negative control consisted of complete culture medium (RPMI 1640) without human serum and was used as a control for unspecific binding of the FITC-conjugated rabbit anti-human IgM.
cComplete culture medium (RPMI 1640) supplemented with a pool of human sera to a final dilution of 1/1,000 was used as a positive control.