Expression and characterization of Helicobacter pylori heat‐shock protein A (HspA) protein in transgenic tobacco (Nicotiana tabacum) plants

Helicobacter pylori infection is prevalent worldwide, especially in developing countries, and is associated with several upper-gastrointestinal-tract diseases. Vaccination is the most effective method to prevent and cure H. pylori infection. By using transgenic plants, plant organs could serve as factories to produce antigens of biotechnological interest. HspA (heat-shock protein A) is an effective antigen and one common to all strains of H. pylori. In the present study, the PCR technique was employed to amplify the gene fragment of the HspA from H. pylori chromosomal DNA. The pGEM-T vector was used for the insertion of the gene fragment of the HspA, and the vector pB1121 was used to construct the plant expression vector. After transformation, the regenerated tobacco plants were identified by PCR and by Northern- and Western-blot analyses. The results verified the integration of this gene into the genome of tobacco (Nicotiana tabacum) and the expression of this gene in transgenic tobacco. Mucosal immunization of mice with transgenic tobacco extracts containing the HspA protein elicited anti-HspA serum antibody that specifically bound to the purified bacterial HspA protein. The present study, using transgenic tobacco plants, provides useful data for the production of an edible plant vaccine.