Figure 7. Characterization of E7-specific interferon-γ (IFN-γ)-secreting CD8⁺ T cells and Pan HLA-DR reactive epitope (PADRE)-specific CD4⁺ T cells in mice vaccinated with PADRE peptide and CRT-E7.

C57BL/6 mice (five per group) were immunized twice with 2 μg per mouse of CRT-E7 DNA intradermally via gene gun and 100 μg per mouse of PADRE in 200 μl incomplete Freund’s adjuvant by subcutaneous tail-base injection, with a 1-week interval. Mice vaccinated with 2 μg CRT-E7 DNA using a gene gun and 200 μl incomplete Freund’s adjuvant by subcutaneous tail-base injection were used as a negative control. Splenocytes were harvested 1 week after the second vaccination and stimulated with E7 peptide or PADRE peptide. Splenocytes without peptide stimulation were used as a negative control. The splenocytes were stained for both CD8 and intracellular IFN-γ. (a, b) Representative figures of the flow cytometry data. The numbers in the upper right corner represent the numbers of (a) E7-specific IFN-γ-secreting CD8⁺ T cells or (b) PADRE-specific CD4⁺ T cells per 3 × 10⁵ splenocytes acquired. (c, d) Bar graphs depicting the numbers of (c) E7-specific CD8⁺ T cells or (d) PADRE-specific CD4⁺ T cells per 3 × 10⁵ splenocytes (means ± SE).