FIGURE 1.

BAFF induces plasmablasts from memory B cells, but not from naive B cells. CD27⁻ naive B cells (A and C) and CD27⁺ memory B cells (B and D) were isolated from human PBMCs, left untreated, or cultured with indicated stimuli for 5 d. (A and B) Representative dot plots in indicated conditions. Total CD19⁺ B cells [(A) naive and (B) memory] were gated and analyzed for differentiation by expression of CD20 and CD38; the number in the plot is the percent of plasmablast among CD19⁺ B cells. (C and D) Graphs show the percent of plasmablast among CD19⁺ B cells in the indicated conditions (mean ± SEM). Dot plots are representative of multiple donors. Statistical comparisons were made with one-way ANOVA followed by Dunnett’s multiple-comparison test. Naive B cells: n = 12; memory B cells: n = 6. *p < 0.05, **p < 0.005, ***p < 0.001, ****p < 0.0001.