The immunization of mice with NDV-infected tumor cells was demonstrated (i) to strongly increase tumor cell immunogenicity, (ii) to augment cooperative interactions between tumor-specific CD4+ Th and CD8+ CTLPs [90,91], and (iii) to increase the frequencies of CD4+ Th and CD8+ CTLPs via the induction of IFN-I [92]. This evidence concerns the gene CD4 and neoplasm.