CD4 and neoplasm: Considering that ICD-specific CD8+ T cell responses as well as ICD-specific CD4+ T cell responses were higher with BVAC-K1117 vaccination than with BVAC-K684 vaccination, inducing ICD-specific T cell responses would be more important to promote antitumor responses than eliciting tumor antigen-specific antibody secretion at least in our HER2-specific tumor models.