Figure 6. Impact of castration on vaccine-induced tumour clearance.

(A) Efficacy of E7-induced protection against weakly tumorigenic (50% tumour development) or (D) highly tumorigenic TC-1 cells (100% tumour development). In both experiments, 9-mth old mice were either ShCx (open square) or Cx (closed square) 5 days after TC-1 inoculation and received a suboptimal dose (5 µg) of E7 vaccine 2 days after surgery. Control mice either received adjuvant only (Quil A; open circle) or maximum vaccine dose (50 µg; closed circle). On day 25, number of E7-specific (B, E) IFN-γ-expressing spleen cells and (C, F) cytotoxic activity were determined. Results were obtained from 4–5 mice per control group and 18–19 mice per test group, expressed as mean±SE of 5–10 mice randomly selected per group for ELISPOT. For CTL assay, % specific lysis at 30∶1 effector∶target ratio is shown; mean = 43–52% for 50 µg group, 0% for 0 µg group.