CD4 and neoplasm: The presence of spatially attracted CD4 + T cells and DCs on the outskirts of CD8 + T cells boosts local CD8 + T-cell differentiation into effector T cells and increases CD8 + T-cell cytotoxicity.228–231 Antigen-induced antitumor responses require both CD4 + and CD8 + T cells that have been primed with tumor antigens.