Impact of E18 on the CD4+ TCR to SEB in vivo. (A) Analysis of CFSE dye dilution among adoptively transferred CD4⁺Vβ8⁺Foxp3⁺ and Foxp3⁻ cells. The figures represent the mean numbers of cell divisions of Foxp3⁺ cells (top values within each dot plot) and Foxp3⁻ cells (bottom values within each dot plot). (B) Average frequencies of Foxp3⁺ cells among Vβ8⁺CD4⁺ cells on day 3 after the indicated treatments. (C) Mice were depleted of Treg cells by anti-CD25 mAb treatment, and Treg cell frequencies among host Vβ8⁺ CD4 cells were analyzed 3 days after SEB injection (left); the mean number of cell divisions among transferred CD25-depleted CFSE⁺ cells was calculated (right). Bars represent means plus or minus SD of 2 to 5 mice per group.