Selective advantage of WASP-expressing cells in WASP^+/− mice. HPCs and hematopoietic lineage cells were defined by surface and intracellular markers, labeled with anti-WASP antibodies, and analyzed by flow cytometry. Percentage of WASP-expressing cells is indicated in (A) the T-cell lineage, (B) the B-cell lineage, and (C) the myeloid lineage. Each color represents data from one mouse. Black bar represents the mean of the group. B indicates B cell; B1/B2, peritoneal B cells; BM, bone marrow; DC, dendritic cell; DN, CD4CD8 double-negative; DP, CD4CD8 double-positive; FO, follicular; Fr, fraction, HPC, hematopoietic progenitor cells; Mo/Ma, monocyte/macrophage; MZ, marginal zone; N, neutrophil; NK, natural killer cell; NKT, NK T cell; nTregs, naturally occurring T cells; PB, peripheral blood; PNA, peanut agglutinin; PPs, Peyer patches; PT, peritoneum; SP, CD4 or CD8 single-positive; SPL, spleen; T1/T2, transitional 1/2 B cell; T2-FO, transitional 2 follicular precursor B cell; T2-MZP, transitional 2 marginal zone precursor B cell; THY, thymus. In vitro cultured Mo/Ma and DCs were obtained by culturing BM cells in vitro for 7 days with M-CSF and GM-CSF, respectively. P values use a t test to compare percentage of WASP-expressing cells in the T-cell, B-cell (right panel), and myeloid lineages to that of HPCs and for the B-cell lineage (left panel) to that of Fr A (pro-B) cells: *P < .05, **P < .01, ***P < .005.