AIM:To examine the molecular mass and identify thebioactivity of MG7 scFv for its application as a targetingmediator in gene therapy of gastric cancer.METHODS:Two strongly positive recombinant phage clonesscreened from MG7 recombinant phage antibody library wereseparately transfected into E.coil TG1.Plasmid wasisolated from the transfected E.coil TG1 and digested byEcoR Ⅱ and Hind Ⅲ to examine the length of exogenousscFv gene.Then,the positive recombinant phage cloneswere individually transfected into E.coil HB2151.Thetransfectant was cultured and induced by IPTG.Perplasmicextracts was prepared from the induced transfectant byosmotic shock.ELISA was used to examine the antigen-binding affinity of the soluble MG_7 scFv.Immunodottingassay was adopted to evaluate the yield of soluble MG7 scFvproduced by transfected E.coil HB2151.Western blot wasused to examine the molecular mass of MG7 scFv.Finally,the nucleotide sequence of MG7 scFv was examined by DNAsequencing.RESULTS:Two positive recombinant phage clones werefound to contain the exogenous scFv gene.ELISA showedthat MG_7 scFv had strong antigen-binding affinity.Immuodotting assay showed that transfected E.coil HB2151could successfully produce the soluble MG7 scFv with highyield via induction by IPTG.The molecular mass ofscFv was 30 kDa by western blot.DNA sequencingdemonstrated that the VH and VL genes of MG7 scFv were363bp and 321bp,respectively.CONCLUSION:We have successfully developed the solubleMG7 scFv which possessed strong antigen-binding affinity. AIM:To examine the molecular mass and identify thebioactivity of MG7 scFv for its application as a targetingmediator in gene therapy of gastric cancer.METHODS:Two strongly positive recombinant phage clonesscreened from MG7 recombinant phage antibody library wereseparately transfected into E.coil TG1.Plasmid wasisolated From the transfected E.coil TG1 and digested byEcoR II and Hind III to examine the length of exogenousscFv gene.Then, the positive recombinant phage cloneswere individually transfected into E.coil HB2151.The transfectant was cultured and induced by IPTG.Perplasmicextracts was prepared from the Induced transfectant byosmotic shock.ELISA was used to examine the antigen-binding affinity of the soluble MG_7 scFv.Immunodopingassay was adopted to evaluate the yield of soluble MG7 scFvproduced by transfected E.coil HB2151.Western blot wasused to examine the molecular mass of MG7 scFv .Finally, the nucleotide sequence of MG7 scFv was examined by DNAsequencing.RESULTS:Two positive Recombinant phage clones were found to contain the exogenous scFv gene.ELISA having that MG_7 scFv had strong antigen-binding affinity.Immuodotting assay showed that transfected E.coil HB2151could successfully produces the soluble MG7 scFv with highyield via induction by IPTG.The molecular mass ofscFv was 30 kDa by western blot.DNA sequencingdemonstrated that the VH and VL genes of MG7 scFv were363bp and 321bp,constructively.CONCLUSION:We have successfully successfully developed the solubleMG7 scFv which possessed strong antigen-binding affinity.