Figure 7. CD27⁺ pro-B cells from FL efficiently gave rise to immature/transitional B cells in vitro.

Differentiation potential of CD27⁺ and CD27⁻ pro-B cells were compared in culture. Sort-purified CD27⁺ or CD27⁻ pro-B cells from 19 wk FL were cultured on an MS5 monolayer [28] in the presence of SCF, IL-7, TSLP, and Flt3 ligand for 10 and 14 days. (A) Flow diagrams of CD19 and CD10 expression on cultured CD45⁺FSC^loSSC^lo FL lymphocytes are shown in the top row. Those CD19⁺CD10⁺ cells were analyzed for surface IgM and IgD expression (middle row), and the IgM⁻IgD⁻ pro-/pre-B cell compartments were further plotted based on CD34 and CD10 expression (bottom row). The number near each gating square indicates the frequency of gated cells within each flow diagram. (B) Absolute cell numbers of input CD19⁺CD10⁺IgM⁻IgD⁻CD34⁺ pro-B, and postcultured CD19⁺CD10⁺IgM⁻IgD⁻CD34⁺ pro-B, CD19⁺CD10⁺IgM⁻IgD⁻CD34⁻ pre-B, and CD19⁺CD10⁺IgM⁺IgD^+/− immature/transitional B cells from CD27⁻ pro-B (○) and CD27⁺ pro-B cells (●) are shown. Representative data are shown from similar results obtained from 2 independent experiments.