IL-6Rαβ (CD126 and CD130) and IL-2Rα (CD25) are up-regulated on plasmablasts or CD40-activated B cells, respectively.

Resting memory B cells were cultured as described in Figure 1. Expression of CD25, CD126, and CD130 was determined on resting memory B cells (day −4), CD40L-activated B cells (day 0), plasmablasts (day 4), and plasma cells (day 7). IL-2R and IL-6R expression was determined in simple staining at days −4 and 0 because the whole population was CD20⁺. From day 2, IL-2R and IL-6R expression was determined in double-staining with anti-CD20–FITC and anti-CD25–PE mAbs or anti-CD20–FITC and anti-CD126–PE or anti-CD20–FITC and anti-CD130–PE mAbs, respectively. Overlay histograms represent the immunofluorescence of CD25, CD126, or CD130 (thick line) and the control (thin line). Results show 1 experiment representative out of 4.