Competitive repopulation in vivo. (A) T-cell–depleted BM cells (4 × 10⁵) from induced knock-out or control mice (Ly5.2; n = 7 per genotype) were mixed with 8 × 10⁵ cells from B6SJL mice (Ly5.1) and transplanted to lethally irradiated B6 nude mice. (B) Ly5.2 reconstitution levels in peripheral blood of primary recipients at 2, 6, and 12 weeks after transplantation. (C) Fraction of Ly5.2 cells within subpopulations of the BM from primary recipient mice killed at 12 weeks after transplantation. (D) Ly5.2 reconstitution levels in peripheral blood of secondary recipients at 12 weeks after transplantation. (E) PCR analysis of hematopoietic colonies from BM of secondary recipients killed at 12 weeks after transplantation. Example from a recipient in one of the knock-out groups, the smaller band (350 base pair [bp]) represents the null alleles from the knock-out donor cells, and the larger band (950 bp) represents the wild-type alleles from the competitor cells. Data represent means ± SEM, P > .6 for all parameters.