Differentiation of naive and memory B cells into polyclonal plasmablastic cells.

CD19⁺ B cells, CD19⁺CD27⁻ naive B cells and CD19⁺CD27⁺ memory B cells were cell-sorted after double-staining with FITC-labeled anti-CD19 and PE-labeled anti-CD27 mAb. The 3 B-cell subsets isolated from the same donor were cultured as described in “Materials and methods,” and the percentage of CD20⁻/CD38⁺⁺ cells was evaluated on day 6. Data shown are from 1 of 2 representative experiments.