Comparison of HPV16 E7-specific CD8+T cell responses induced by CRT/E6E7L2 DNA vaccination. Summary of systemic (A) and tumor infiltrating (B) HPV16 E7-specific CD8+ T cells. Briefly, 5-8 week old female C57BL/6 mice were (5 mice/group) were challenged intravaginally with 2x104 TC-1 Luc cells/mouse. From day 7, mice were either left untreated or immunized with 10 μg/mouse of CRT/E6E7L2 DNA vaccine by intramuscular injection only or followed by electroporation. The mice were boosted twice at 3-day intervals with the same regimen. 8 days after the last vaccination, splenocytes (A) or tumor infiltrating lymphocytes (B) were harvested and surface stained with anti-mouse CD8 and HPV16 E7aa49-57 peptide loaded H2-Db tetramer. The cells were acquired with FACSCalibur.