In vivo induction of OVA-specific CTL by DC. DC isolated from bone marrow (bmDC) or spleens (sDC) and splenic macrophages (sMac) from C57BL/6 mice were pulsed with soluble ovalbumin and 4 × 10⁵ DC were injected intraperitoneally on day 0 and 7 into C57BL/6 mice. Splenocytes from immunized mice were harvested on day 14 and stimulated with syngeneic splenocytes pulsed with 10 μmol/L OVA peptide. The primed CTL were then assayed for their ability to lyse E.G7 cells, transfectants expressing the OVA peptide, or EL-4 tumor cells either pulsed with 1 μmol/L OVA peptide or left unpulsed. Mice injected with saline or unpulsed DC gave no response. (▪) EL-4 + OVA peptide; (•) EL-4; (⋄) EG.7.