Analysis of hematopoietic progenitors in Tc1 mice. (A) Two-dimensional contour plots of bone marrow cells showing flow cytometric analysis used to identify hematopoietic progenitors. Numbers indicate percentage of cells falling into the gates. Lineage⁻ cells were separated by expression of cKit and Sca1, and the earliest progenitors were identified as Lineage⁻Sca1⁺cKit⁺ (LSK). Lineage⁻Sca1⁻cKit⁺ cells were further subdivided by expression of FcγR and CD34 into common myeloid progenitors (CMPs, CD34⁺FcγR⁻), the granulocyte-macrophage progenitors (GMPs, CD34⁺FcγR⁺), and the megakaryocyte-erythroid progenitor (MEPs, CD34⁻FcγR⁻). Note that before flow cytometric analysis, Lineage⁺ cells had been depleted, to enrich for Lineage⁻ cells, thus explaining the apparently high percentage of Lineage⁻ cells. (B-D) Graphs showing mean (± SEM) percentage of hematopoietic progenitors in the spleen (B-C) and bone marrow (D-E) of Tc1 and wild-type mice aged 2 months (B,D) and older than 15 months (C,E; 2 months, n = 8 [Wt], n = 13 [Tc1]; > 15 months, n = 7 [Wt], n = 11 [Tc1]).