Immunoprotection of recombinant antigen LTB-UreB-HpaA in Helicobacter pylori infected mice and immunoenhancement of the inner adjuvant LTB

In order to increase antigenicity of H. pylon-specific antigens and decrease the cost of further industrial production, we used a special PCR with linking primers to construct a fusion gene containing H. pylon ureB and hpaA genes and E. coli ltB gene, and to costract its prokaryotic expression system pET42a-ltB-ureB-hpaA-E. coliBL21DE3. The sequencing result indicated the 100% nucleotide sequence homology of the constructed ltB-ureB-hpaA fusion gene compared to those of the original separated genes. Output of the target recombinant protein rLTB-UreB-HpaA was approximate 15% of the total bacterial proteins measured by SDS-PAGE. The rLTB-UreB-HpaA could induce the immunized rabbits to produce specific antibodies with immunodiffusion titer of 1:8, and could combine to the commercial rabbit antibody against the whole cell of H. pylon as well as rabbit anti-UreB and anti-HpaA sera by using Western bolt assays. Using GM1-ELISA, the ability of rLTB-UreB-HpaA binding to bovine GM1 was confirmed. And rLTB-UreB-HpaA (200 μg per mouse) could prevent 100% of the immunized BaLb/C mice from H. pylon strain SS1 infection. The co-administration with 10 μg rLTB, the rUreB or rHpa could increase its protective rates in the immunized mice from 66.7% to 81.8% and 83.3%, respectively. All these data leads a conclusion that rLTB-UreB-HpaA is a great potential as a practical genetic engineering vaccine to prevent H. pylon infection.