Published online Apr 15, 2002. doi: 10.3748/wjg.v8.i2.308
Revised: November 1, 2001
Accepted: November 8, 2001
Published online: April 15, 2002
AIM: To construct a recombinant vector which can express Mr26000 outer membrane protein (OMP) from Helicobacter pylori (H. pylori), and to obtain the vaccine protecting against H. pylori infection and a diagnostic reagent kit quickly detecting H. pylori infection.
METHODS: The gene encoding the structural Mr26000 outer membrane protein of H. pylori was amplified from H. pylori chromosomal DNA by PCR, and inserted in the prokaryotic expression vector pET32a(+), which was transformed into the 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 antigenicity of recombinant protein was studied by ELISA or immunoblotting and immunized Balb/c mice.
RESULTS: The gene of Mr26000 OMP was amplified to be 594 base pairs, 1.1% of the cloned genes was mutated and 1.51% of amino acid residues was changed, but there was homogeneity between them. The recombinant fusion protein encoded objective polypeptides of 198 amino acid residues, corresponding to calculated molecular masses of Mr26000. The level of soluble expression products was about 38.96% of the total cell protein. After purification by Ni-NTA agarose resin columniation, the purity of objective protein became about 90%. The ELISA results showed that recombinant fusion protein could be recognized by patient serum infected with H. pylori and rabbit serum immunized with the recombinant protein. Furthermore, Balb/c mice immunized with the recombinant protein were protected against H. pylori infection.
CONCLUSION: Mr26000 OMP may be a candidate vaccine preventing H. pylori infection.