CD4 and neoplasm: We have elaborated this in vitro culture system from the notion that optimal induction of CD8+ T cells specific for exogenous antigens in vivo requires the combination of DC dependent cross presentation, help by CD4+ T cells and the addition of IL-12 and IL-7, whose presence was shown to be critical for the efficient induction of anti-tumor effector T cells by Montagna et al [15].