Early kinetics of the PE-specific B cell response. (A) Representative flow cytometry analysis of PE-specific B cells found in various lymphoid organs 29 d after s.c. injection of animals with 15 µg PE emulsified in CFA (PE/CFA) in the base of the tail and in the absence of injection. Each sample was analyzed directly ex vivo (top) or after ex vivo enrichment of PE-binding cells using anti-PE magnetic microbeads (bottom). The dots plots show B cells identified by flow cytometry in pooled spleen and LN samples as cells that stained with anti-B220 but not anti-Thy1.2, CD11c, Gr-1, or F4/80. Ing, inguinal LN; Peri LN, periaortic LN; Ax, axillary LN; Br, brachial LN; Cerv, cervical LN; Mes LN, mesenteric LN. Shown is a representative of two similar experiments. (B) Representative flow cytometry analysis of CD38 and GL7 expression by PE⁺ B cells 29 d after injection of PE/CFA, along with the total number of donor PE-specific memory (CD38⁺ GL7⁻) and GC (CD38⁻ GL7⁺) B cells in the specified lymphoid organs. Each point represents an individual mouse and the bars represent the means (n = 3). Shown is a representative of two similar experiments.