AIM:To construct a recombinant vector which can expressM,26000 outer membrane protein(OMP)from Helicobacterpylori(Hp),and to obtain the vaccine protecting againstHp infection and a diagnostic reagent kit quickly detectingHp infection.METHODS:The gene encoding the structural M_r 26000 outermembrane protein of Hp was amplified from Hpchromosomal DNA by PCR,and inserted in the prokaryoticexpression vector pET32a(+),which was transformed intothe Top10 E.coli strain.Recombinant vector was selected,identified and transformed into BL-21(DE3)E.coli strain.The recombinant fusion proteins were expressed.Theantigenicity of recombinant protein was studied by ELISA orimmunoblotting and immunized Balb/c mice.RESULTS:The gene of M_r 26 000 OMP was amplified to be594 base pairs,1.1% of the cloned genes was mutated and1.51% of amino acid residues was changed,but there washomogeneity between them.The recombinant fusion proteinencoded objective polypeptides of 198 amino acid residues,corresponding to calculated molecular masses of M_r 26000.The level of soluble expression products was about 38.96 %of the total cell protein.After purification by Ni-NTA agaroseresin columniation,the purity of objective protein becameabout 90 %.The ELISA results showed that recombinantfusion protein could be recognized by patient serum infectedwith Hp and rabbit serum immunized with the recombinantprotein.Furthermore,Balb/ c mice immunized with therecombinant protein were protected against H.pylori infection.CONCLUSION: Mr 26 000 OMP may be a candidate vaccine preventing Hp infection. AIM: To construct a recombinant vector which can express M, 26000 outer membrane protein (OMP) from Helicobacter pylori (Hp), and to obtain the vaccine protecting against HP infection and a diagnostic reagent kit rapid detecting HPV infection. METHODS: The gene encoding the structural M_r 26000 outermembrane protein of Hp was amplified from Hpchromosomal DNA by PCR, and inserted in the prokaryotic expression vector pET32a (+), which was transformed into TOP10 E. coli strain. Recombinant vector was selected, identified and transformed into BL-21 (DE3) E. coli strain.The recombinant fusion proteins were expressed. The antigenic of recombinant protein was studied by ELISA orimmunoblotting and immunized Balb / c mice .RESULTS: The gene of M_r 26 000 OMP was amplified to be594 base pairs, 1.1% of the cloned genes was mutated and1.51% of amino acid residues was changed, but there washomogeneitybetween them. The recombinant fusion proteinencoded objective polypeptides of 198 amino acid residues, corresponding to cal culated molecular masses of M_r 26000. The level of soluble expression products was about 38.96% of the total cell protein. After purification by Ni-NTA agaroseresin columniation, the purity of objective protein became about 90%. ELISA results showed that recombinantfusion protein could be recognized by patient serum infected with Hp and rabbit serum immunized with the recombinant protein. Fultrthermore, Balb / c mice immunized with therecombinant proteins were protected against H. pylori infection. CONCLUSION: Mr 26 000 OMP may be a candidate vaccine preventing Hp infection.