Induction of OVA-specific cytolytic activity by heat-denatured and native OVA protein, E.G7 cells and VSV-OVA viral infection. (A) C57BL/6 mice were immunized with irradiated E.G7 cells, heat-denatured or native OVA or infected with VSV-OVA. One week after the last immunization or after viral infection, spleen cells were stimulated in vitro with ova257-264 for 5 days and the secondary lytic activity against E.G7 was tested by ⁵¹Cr release assay. Lytic activity against EL4 at the E:T ratio shown was <10%. (B) C57BL/6 mice were immunized with irradiated E.G7 cells or infected i.v. with VSV-OVA. One week later, primary lytic activity of spleen cells against E.G7 was measured. Lytic activity against EL4 at the E:T ratio shown was <2%.