Fig 2. Schistosome antigens mainly activate the marginal zone B cell subset of the spleen.

C57BL/6 were treated as in Fig 1, splenic follicular (FO) B cells (CD19⁺CD23⁺CD21^low) and marginal zone (MZ) B cells (CD19⁺CD23^-CD21^hi) FACS sorted, and restimulated for 2 days with SEA (20 μg/ml). (A) Gating scheme for both B cell subsets within the CD19⁺ gated B cell population. (B, C) Cytokine concentration in culture supernatants as determined by ELISA. (D) Intracellular IL-10 expression of B cell subsets after addition of Brefeldin A to the last 4 hours of the culture. (E) Mean fluorescence intensity of CD86 expression of B cell subsets. Summary of 2 experiments with N = 6 (B, C) or 3–5 experiments with N = 13–21 (D, E). Significant differences by Mann-Whitney test are indicated with * p < 0.05, *** p < 0.001. Significant differences between B cell subsets by Wilcoxon paired test are indicated with ^# p < 0.05, ^## p < 0.01, ^### p < 0.001.