Objective:ToobtainrecombinantTreponemapallidumsubsp,pallidum(TP17KD)lipoproteininlargequantitiesbyamplificationandtofurtherpurifyantigensforlaboratorydiagnosisofsyphilisanddevelopmentofasyphilisvaccine.Method:TheTppl7lipoproteingenewasamplifiedfromtheTP(strainNichols),andthenitwasrecombinatedintoaplasmidpMAL-2candclonedwithinE.coli12-TB1.ThehostbacteriacontainingrecombinantplasmidswereinducedwithIPTG.TheTpp17KDlipoproteingenewasamplifiedbyus-ingPCRandpositivecloneswerescreenedwithdoubledigestionandPCR.RecombinantplasmidsweretransformedintoE.coliandtheE.colicarryingrecombinantplasmidswereinduced.TheexpressionofTP17KDwasdetectedbysodiumdedecylsulfate-polyacrylamidegelelectrophoresis(SDS-PAGE)andimmunoblot.Results:GelstainingwithCoomassieblueG-250showedthattheinducedE.colicarryingrecombinantplasmidcouldproduce60KDfusionproteinathighlevels.Gelscanningshowedthat17KDproteinexpressioninE.coliaccountedfor10%oftotalcellularprotein.Therecombinantproteinantigenreactedwiththeseraofsyphilispatients.Conclusion:Ourstudylaysacornerstonefordevelopingnewtechniquesoflaboratorydiagnosisforsyphilisandnewvaccines.Preliminaryclinicalapplicationshowedthatthefusionproteincouldbeusedforthediagnosisofsyphilis.