The effect of Shh deficiency and Gli2 deficiency on Rag1^−/− FTOC stimulated with anti-CD3. (A) Phenotype of E15.5 Shh^−/−Rag1^−/− and littermate Rag1^−/− thymi. (Shh^−/−Rag1^−/−, n = 5; littermate Rag1^−/−, n = 9). Cells positive for CD45.2⁺ (left dot plot) were analyzed for CD25 and CD44 expression (right dot plot). (B) Propidium iodide staining of thymocytes from Shh^−/−Rag1^−/− and littermate Rag1^−/− thymi as in panel A. The percentage of cells in G2+M/S is given. (C) E15.5 Shh^−/−Rag1^−/− and littermate Rag1^−/− fetal thymus organ cultures (FTOCs) were treated for 3 days with 1 μg/mL anti-CD3 mab. Dot plots show CD4 and CD8 profiles. (Shh^−/−Rag1^−/−, n = 5; littermate Rag1^−/−, n = 9). Histograms show propidium iodide staining on thymocytes from the anti-CD3–treated Shh^−/−Rag1^−/− and littermate Rag1^−/− FTOC. The percentage of cells in G2+M/S is given. (D) E17.5 Gli2^−/−Rag1^−/− and littermate Rag1^−/− FTOCs were treated for 5 days with 0.5 μg/mL anti-CD3 mab. Dot plots show CD4 and CD8 profiles. (Gli2^−/−Rag1^−/−, n = 4; littermate Rag1^−/−, n = 8.)