CD4 and neoplasm: Using a tumorigenic CMS5-VP1 tumor model, the vaccine-induced a potent antitumor efficacy in a dose-dependent manner was evidently demonstrated and mainly mediated by both VP1-specific CD4+ and CD8+ T-cell responses against the growth of CMS5-VP1 tumors in vaccinated BALB/c mice since the depletion of CD4+ and CD8+ T cells reverse the antitumor effects.