Differential intrathymic differentiation kinetics of MPPs and CLPs do not depend on differential thymus-seeding capacity. (A-B) Sorted lin⁻CD27⁺CD117^hiSca-1⁺CD135⁺ MPPs and lin⁻CD27⁺CD117^loSca-1^loCD127⁺-CD135⁺ CLPs from B6 CD45.2 mice were intrathymically injected into B6 CD45.1 mice. Donor-derived cells were analyzed by FACS for the expression of CD4 and CD8 after 7, 14, 21, and 28 days. (A) Representative FACS plots of donor-derived (CD45.1⁺) thymocytes. Numbers in quadrants indicate frequency of donor-derived cells. (B) Analysis of donor-derived thymic subsets of at least 3 mice per group (DN: CD4⁻CD8⁻; DP: CD4⁺CD8⁺; SP: CD4⁺CD8⁻ and CD4⁻CD8⁺). (C) Lin⁻ BM cells from B6 CD45.1 mice (test) were depleted of CD117^hi cells, CD127⁺ cells, or both (double), mixed with lin⁻ BM cells from B6 CD45.1/CD45.2 mice (competitor), and transferred intravenously into Il7ra-deficient hosts. Ctl indicates mixture of nondepleted B6 CD45.1 lin⁻ BM cells with B6 CD45.1/CD45.2 lin⁻ BM cells. Five days after transfer thymocytes were harvested, cultured on OP9-DL1 cells for an additional 14 days, and analyzed for the expression of CD45.1 and CD45.2. Numbers indicate frequencies of cells in adjacent gates.