Intrinsic B-cell defect in KA/KA BM. (A) Genotype of the tail DNA and BM B220⁺ cell DNA of WT and KA/KA recipient mice analyzed using PCR. (B) Statistical analysis of BM pre-pro-B, pro-B, and pre-B-cell populations of γ-irradiated recipient mice receiving BM from the donor mice as indicated. The data represent means ± SD calculated from 4 independent BM-transfer experiments. (C) Flow cytometric analysis of BM and splenic WT (CD45.1⁺) and KA/KA (CD45.1⁻) B cells in the BM and spleens of irradiated mice receiving mixed WT (CD45.1⁺) and KA/KA (CD45.1⁻) BM cells.