Lymphocyte egress from LNs. (A) A mixture of WT and DKO T cells were transferred into C57BL/6 mice, and 12 hours later Mel-14 was injected into the mice to stop further entry into LNs. Graph shows mean ± SEM ratio of DKO to WT CD4⁺ or CD8⁺ T cells in LNs as a function of time after Mel-14 injection. The ratio was normalized to the ratio of DKO to WT T cells in the cells injected into the mice. (B) Graph shows percentage (mean ± SEM) CD4⁺ or CD8⁺ T cells remaining as a function of time after Mel-14 injection, normalized to the number of cells at 0 hours, which was set to 100%. Data in panels A and B are from 2 independent experiments. (C) Graph shows mean ± SEM percentage migration of WT or DKO EYFP⁺ T cells (CD4⁺ or CD8⁺) in a Transwell assay in response to S1P at the indicated concentrations, or in the absence of chemokine (N). Data are from 1 representative experiment of 2 independent experiments. *P < .01; ***P < .001.