简介：AIM:Toconstructanon-resistantandattenuatedSalmonellatyphimurium(S.typhimurium)strainwhichexpressesconservativeregionofadhesionABofHelicobacterpylori(Hpylon)andevaluateitsimmunogenicity.METHODS:TheABgeneamplifiedbyPCRwasinsertedintotheexpressionvectorpYA248containingasdgeneandthroughtwotransformationsintroducedintothedeltaCya1deltaCrp1deltaAsdattenuatedSalmonellatyphimuriumstrain,constructingbalancedlethalattenuatedSalmonellatyphimuriumstrainsX4072(pYA248-AB).BridgedELISAmethodwasusedtomeasuretheexpressionofABantigeninsonicateandculturesupematant.AccordingtothemethoddescribedbyMeacock,stabilityoftherecombinantwasevaluated.Semi-lethalcapacitytestwasusedtoevaluatethesafetyofrecombinant.Theimmunogenicityofrecombinantwasevaluatedwithanimalexperiments.RESULTS:TheattenuatedS.typhimuriumX4072(pYA248-AB)whichexpressesABwassuccessfullyconstructed.Furthermore,bridgedELISAassayshowedthatthecontentofABinrecombinantX4072(pYA248-AB)culturesupematantwashigherthanthatwasinthalluslyticliquor.AndafterrecombinantX4072(pYA248-AB)wasculturedfor100generationswithoutselectionpressure,bheentirerecombinantbacteriaselectedrandomlycouldgrow,andtheABantigenwasdefectedpositivebyELISA.ThegrowthcurveoftherecombinantbacteriashowedthatthegrowthstatesofX4072(pYA248)andX4072(pYA248-AB)werebasicallyconsistent.ThesurvivalrateofC57BL/6wasstill100%,at30daftermicetakingX4072(pYA248-AB)1.0×l0^10cfuorally.OralimmunizationofmicewithX4072(pYA248-AB)inducedaspecificimmuneresponse.CONCLUSION:Invitrorecombinantplasmidappearstobestableandexperimentsonanimalsshowedthattherecombinantstrainsweresafeandimmunogenicinvitro,whichprovidinganewliveoralvaccinecandidateforprotectionandcareofHpyloriinfection.