Objective:Tostudythevaccinepotencyofgene-modifiedtumorcells.Methods:TheEL-4lymphomawastransducedwithrecombinantretroviruscontainingthemurineGM-CSFgeneorB7-1gene.Theeffectofgenetransductiononantitumorimmunitywasinvestigated.Results:Flowcytometryanalysisshowedthatexpressionoftheirsurfacemarkerbetweenwild-typeEL-4cellsandgenetransducedtumorcellswasthesameexceptforCD80positiveinB7-1genetransducedcells.GM-CSFgeneorB7-1genetransducedEL-4cellsresultedinremarkablelossoftumorigenicityinsyngeneticmice.ThesystemicprotectiveimmunitywasinducedagainstthechallengewithEL-4/wtcells.TherapeuticvaccinewithEL-4/GM-CSForEL/7-1cellscouldretardthegrowthofestablishedearly-stageEL-4/wttumorsignificantly,butnotretardthegrowthoflate-stageEL-4/wttumor.IrradiatedGM-CSFgenetransducedEL-4cellsshowedstrongvaccineeffectagainstEL-4cellchallenge,butirradiatedB7-1genetransducedEL-4cellsshowedweakvaccineeffect.RemarkablecooperativeantitumoreffectagainstEL-4cellchallengewasobservedwhenbothirradiatedEL-4/GM-CSFandEL-4/B7-1wereinoculatedtogether.Conclusion:GM-CSFgeneorB7-1genetransducedcombinationofthetwokindsofvaccinemayhavepotentialapplicationvalueinhumancancertreatment.
