Wip1KO mice exhibit a reduction of B cells in the periphery immune tissues and bone marrow due to a cell-intrinsic defect. (A) Total number of lymphocytes in the peripheral blood of 6- to 8-week-old WT and Wip1KO mice was determined using a blood cell counter. Data are expressed as means ± SD (n ≥ 25). (B) Representative FACS plots of B cells and CD4⁺ T cells in the peripheral blood of WT and Wip1KO mice. (C) The percentage of B cells in the peripheral blood of WT and Wip1KO mice (n ≥ 25). (D) Representative FACS plots of B cells and CD4⁺ T cells in the spleen, pLNs, and mLNs of 6- to 8-week-old WT and Wip1KO mice. (E) The bar graphs show the percentage and number of B cells in the spleen, pLNs, and mLNs of WT and Wip1KO mice (n = 8). (F) Representative FACS plots of B cells in the bone marrow of 6- to 8-week-old WT and Wip1KO mice. (G) The percentage of B cells in the bone marrow was significantly lower in Wip1KO mice than in WT mice. (H) The number of B cells in the bone marrow was significantly lower in Wip1KO mice than in WT mice (n ≥ 20). (I) The scheme of the experimental design for bone marrow transplantations. (J) The percentage of WT and Wip1KO donor-derived B cells in the peripheral blood of recipient mice 12 weeks after transplantation (n = 3-5). (K) The percentage of WT and Wip1KO donor-derived B cells in the donor-derived cells in the spleens, pLNs, and mLNs of mixed-chimera recipients 12 weeks after transplantation is shown (n = 3-5). (L) The percentage of WT and Wip1KO donor-derived B cells in the bone marrow of mixed-chimera recipients 12 weeks after transplantation is summarized (n = 3-5). Data are expressed as means ± SD. *P < .05, **P < .01, and ***P < .001 compared with WT mice. PBLs, peripheral blood lymphocytes; SPL, spleen.