Flow cytometric purification of mouse B-cell precursors in three steps. Step 1 (top row): Enrichment of lymphoid cells. Shown is a forward–sideward scatter plot of total femoral bone marrow cells. The boxed area indicates the lymphoid gate. Second step (middlerow): Enrichment of c-kit+B220+ pre-BI cells, CD25 +B220+ pre-BII cells, and sIgM+B220+ immature/mature B cells. Surface marker staining of three aliquots of lymphoid-gated bone marrow cells is shown. Pre-BI and immature/mature B cells were sorted as indicated by the gates displayed as boxes in the top and middle rows. Third step (bottom row): Separation of pre-BII cells according to cell size. Shown are forward–sideward scatter plots of cells gated as in the middle row. Pre-BII cells were separated according to cell size into the large pre-BII cells (right box) and small pre-BII cells (left box). Note that pre-BI cells consist of a small and a large subpopulation, which were not separated. Immature and mature B cells were sorted according to the gates shown in themiddle row, right panel. As both populations consist of homogeneous small cells, only one back-gated forward–sideward scatter plot is shown in the right panel of thebottom row.
