Absolute number of B220+, B220+IgM− and B220+IgM+ B cells in spleen of IRF4+/+, IRF4+/−, IRF4+/+Myc and IRF4+/−Myc mice (×106).

Total number of B220+, B220+IgM− and B220+IgM+ B cells in mice of different genotypes under study. Cell were isolated from spleen of five-week- old IRF4+/+, IRF4+/− IRF4+/+Myc and IRF4+/−Myc mice. The cells were stained with antibodies against B220 and IgM and analyzed by FACS. The numbers are the averages and standard deviations of the results for a total of five mice in each group.**p