W/W FL cells are not capable of reconstituting thymocytes in RAG-2^−/− recipient mice. Thymocytes from Ly5.2⁺RAG-2^−/− mice (first row), Ly5.2⁺RAG-2^−/− mice reconstituted with day 13 Ly5.1⁺W/W FL cells (second row) and Ly5.2⁺RAG-2^−/− mice reconstituted with day 13 Ly5.1⁺ wildtype FL cells (third row) were analyzed by three-color flow cytometry for the presence of Ly5.2, CD4, and CD8. Total cell counts are shown at the left of each panel. Two parameters are shown at a time: Ly5.2 versus CD4 (left column) and CD4 versus CD8 (right column). The contour plots of CD4 versus C8 of the reconstituted mice (c and e) are gated on donor-derived (Ly5.2⁻) cells only. Numbers given in quadrants and gates indicate percentages.