Differential proliferative response of naive T cells in Rag1^−/− or TCRβ^−/− lymphopenic recipients. (A) CFSE profiles of adoptively transferred Ly5.1 naive T cells. Cells were collected 7 days after transfer from the indicated lymphoid tissues. Shown are the CFSE profiles of Ly5.1⁺ gated donor T cells. (B) Absolute numbers of donor cells were calculated. Each symbol represents individual recipient mice. Mean cell recovery (×10⁶) ± SD of CD4 T cells and CD8 T cells in spleen of Rag1^−/− mice: 0.56 ± 0.46 and 0.3 ± 0.08, respectively (P = .18). Mean cell recovery (×10⁶) ± SD of CD4 T cells and CD8 T cells in spleen of TCRβ^−/− mice: 4.73 ± 1.04 and 0.59 ± 0.22, respectively (P < .001). Mean cell recovery (×10⁶) ± SD of CD4 T cells and CD8 T cells in LN of Rag1^−/− mice: 0.47 ± 0.18 and 0.28 ± 0.06, respectively (P = .02). Mean cell recovery (×10⁶) ± SD of CD4 T cells and CD8 T cells in LN of TCRβ^−/− mice: 0.33 ± 0.1 and 0.09 ± 0.05, respectively (P < .001). Mean cell recovery (×10⁶) ± SD of CD4 T cells and CD8 T cells in mesenteric LN of Rag1^−/− mice: 2.81 ± 0.71 and 1.1 ± 0.43, respectively (P < .001). Mean cell recovery (×10⁶) ± SD of CD4 T cells and CD8 T cells in mesenteric LN of TCRβ^−/− mice: 3.84 ± 1.1 and 0.3 ± 0.16, respectively (P < .001). (C) The ratio of adoptively transferred donor CD4 and CD8 T cells in the spleen, the LN and the mesenteric LN was calculated. Shown are the mean ± SD of individually tested mice (n = 6-11).