Fig. 4. Mdm2^+/–Eµ-myc transgenics have drastically reduced numbers of B cells. (A and B) Splenic cells from mice of the indicated genotypes prior to any detectable disease were stained with fluorescent antibodies specific for B cells (IgM, CD19) and T cells (CD3) and subjected to flow cytometry phenotype analysis. The location of the quadrant axes was determined from isotype controls, and the numbers in the quadrants are the percentage of cells in each of those quadrants. Data are representative of five separate experiments.