Vβ gene segment usage by naive and HEL12–27-responsive CD4 T cells from Tssp−/− and WT control mice. CD4 T cells isolated from HEL-primed WT or Tssp−/− mice were CFSE labeled and stimulated with HEL12–27 peptide in the presence of irradiated WT splenocytes. After 5–6 d of culture, dividing CD4 T cells were FACS sorted before RT-coupled real-time PCR analysis. Alternatively, LN CD4 T cells were isolated from 9–13-wk-old naive mice. Box and whiskers graph shows the Vβ gene usage for naive or HEL-specific CD4 T cells isolated from WT or Tssp−/− (KO) mice (n = number of mice). Horizontal bars show the median values, boxes show the 25th and 75th percentile, and bars show the minimal and maximal values. In WT mice, Vβ6 usage was significantly higher than that of all other Vβ genes, except Vβ7 (P < 0.05). The p-value of those Vβ with an increased representation in CD4 T cells from primed mice as compared with that of naive mice is shown (*, P < 0.05; **, P < 0.01).