Figure 6. Flow cytometry analysis to characterize Pan HLA-DR reactive epitope (PADRE)-specific CD4⁺ T cells in mice vaccinated with PADRE peptide or Ii-PADRE DNA.

C57BL/6 mice (five per group) were immunized twice with 100 μg per mouse of PADRE peptide subcutaneously or 2 μg per mouse of Ii-PADRE DNA intradermally, with a 1-week interval. Splenocytes from vaccinated mice were harvested 1 week after the second vaccination and stimulated with PADRE peptide. Splenocytes without peptide stimulation were used as a negative control. The splenocytes were stained for both CD4 and intracellular interferon-γ (IFN-γ). (a) Representative figure of the flow cytometry data. The numbers in the upper right corner represent the number of PADRE-specific CD4⁺ T cells per 3 × 10⁵ splenocytes acquired. (b) Bar graph depicting the number of PADRE-specific CD4⁺ T cells per 3 × 10⁵ splenocytes (means ± SE). The data presented in this figure are from one representative experiment of two performed.