FIGURE 1. Development of IMP CD8⁺ T cells via hematopoietic MHCI selection independent of the thymus.

(A) Representative flow cytometric analysis of IMP CD8⁺ T cells (upper panel, CD44^hiCD122⁺) and P/I induced IFN-γ production (lower panel). Donor TCRβ⁺CD8α⁺ cells from WT→WT (MHCI⁺CD45.2⁺), MHCI^−/−→WT (MHCI⁻CD45.2⁺) and WT→MHCI^−/− (MHCI⁺CD45.2⁻) chimeras are shown. (B&C) The thymus is not required for development of IMP CD8⁺ T cells. (B) Bone marrow chimeras were generated as indicated and donor TCRβ⁺CD8α⁺ cells analyzed by flow cytometry for CD44 and CD122, and IFN-γ producing capacity induced by P/I, compared to those from WT and Nude mice. (C) Percentages of IMP, naïve and P/I induced CD44^hi IFN-γ producing CD8⁺ T cells, along with numbers of total, IMP and naïve CD8⁺ T cells, in “WT→WT” and “WT→Nude” chimeras. n = 4 in each group. *p < 0.05 by Student’s t test.