Expression Of Helicobacter Pylori AlpA Gene In Lactococcus Lactis And Its Immunogenicity Analysis

Helicobacter pylori is a Gram-negative microaerophilic bacillus that infects the stomachs of more than half of the global population. It has been confirmed that H.pylori is the main cause of chronic gastritis and pepticulcer disease, and has a close relation to gastric mucosa-associated lymphoid tissue (MALT) lymphoma and gastric adenocarcinoma. The World Health Organization defined it as a class I carcinogen. Vaccine will be an effective and economic approach to prevent infection diseases of mass population.With in-depth study of H.pylori pathogenicity, it was found H.pylori pathogenic factors, including a number of factors, such as urease, catalase, heat shock proteins, adhesins, etc., but particularly the most critical adhesin. Adhesins alpA encoding 518 amino acids, in vitro adhesion experiments show that the surface of the bacterium and its fusion protein anti-serum can completely prevent the adhesion of Hp on the gastric tissue. Ramom and other scholars, confirmed by guinea pig model alpA, alpB defect on the adhesion of H.pylori colonization is very unfavorable, alpA of immunogenicity in animal models have laboratory evidence.Lactococcus lactis is a Gram-Positive food-grade bacterium and has a long his-tory of widespread use in the food industry for the production of fermented milk products. And it can stimulate a mucosal immune response as a adjuvant in the intes-tinal tract. Lactococcus lactis is approximately the same size as biodegradable mi-croparticles that are known to be taken up by M cells and have been shown to be ca-pable of acting as effective oral vaccine vehicles.In this study, the alpA gene was amplified and clone into the prokaryotic expressive vector pNICE:sec. The recombi-nant vector was transformated into Lactococcus lactis strain NZ9000. The fusion pro-tein was expressed in L.lactis by the induction of the nisin. The quantity of expression accounted for 9.6% of the total bacterial protein. Western bolt analysis confirmed that fusion protein could be recognized specifically by the serum of anti-H.pylori. The re-combinant L.lactis expressing alpA protein was used to vaccinate mice and the speci-fical IgA and IgG was elicited. These results suggest that the recombinant L.lactis can elicit the local mucosal and the systemic immune response delivered through oral route. This may be useful for the precaution and eradication of the infection of H.pylori. So this recombinant L.lactis may be a good vaccine in the future. These results would be helpful for the development of oral vaccine against H.pylori.