Figure 1.

The peritoneal cavity of allotype chimeras contains B-1 and B-2 cells of differing allotypes. Shown are 5% contour plots of PerC cells from the indicated mouse strains after gating for live, B220⁺, CD4⁻, CD8⁻, F4/80⁻ cells. Cells were stained either for total or allotype-specific IgM and IgD. Frequencies of B-1 cells (IgM^hi, IgD^lo) and B-2 cells (IgM^lo, IgD^hi) were calculated from the indicated gates. These gates were chosen to exclude CD23⁺ CD43⁻ CD5⁻ cells in the B-1 cell gate, and CD11b⁺, CD5⁺ cells in the B-2 cells gate (data not shown). In chimeras all Igh^a-expressing cells are B-1 cells, and the majority of Igh^b-expressing cells are B-2 cells.