Quantifying GC-derived and GC-independent memory B cells. (A) Representative flow cytometry plots showing the expression of isotype switched (IgG⁺IgA⁺IgE⁺) and unswitched (IgM⁺IgD⁺) Ig on PE-specific WT and Bcl6^−/− memory populations (CD38⁺ GL7⁻) in WT:Bcl6^−/− mixed chimeras at the indicated time points after injection. p.i., post injection. Combined data from five experiments showing the numbers of PE-specific WT and Bcl6^−/− (B) IgM⁺ memory and swIg⁺ (C) memory cells. The mean and SEM (n = 3–5) are shown for all time points.