THE STUDY ON THE STIMULATION OF THE IMMUNE SYSTEM IN THE INFUSED BALB/c MICE BY PCDNA3.1(-)-FLAA RECOMBINANT VECTOR AGAINST Helicobacter pylori INFECTION USING MOLECULAR TECHNIQUES

Helicobacter pylori, a Gram-negative flagellated microaerophilic bacterium, is associated with inflammation of the stomach, duodenal and gastric ulcer disease, and gastric cancer. This bacterium infects almost half of the world's population stomachs. One of this pathogen's immunogenic genes is the flaA gene that can stimulate the host immune system. In our previous study, the immune response in pCDNA3 1(-)-flaA infused BALB/c mice against H. pylori infection was investigated using quantitative real-time PCR (q-RT-PCR). After preparation of pCDNA3 1(-)-flaA recombinant plasmid at largescale, the mice were infused in the hip muscle by a recombinant vector with or without chitosan nanoparticles. The pcDNA3 1(-) was used as the negative control. The blood and tissue specimens of each mouse were collected at different times. The expression levels of cytokine genes (including IL-2, IFN gamma, IL4) and the internal control gene were evaluated in peripheral blood cells using a q-RT-PCR method. Also, the flaA gene expression in mice muscle was measured at 15, 30, and 45 days after the last injection. In infused mice by pcDNA3 1(-) flaA, the IL-2 and IFN gamma genes were increased statistically (p <0.001) and IL4 was significantly decreased (p <0.001). Moreover, the expression of flaA gene in mice muscles was decreased by passing the time. Furthermore, the infused mice by pcDNA3 1(-)-flaA + nanoparticles showed a better immune response because of alteration in IL4 expression. Our findings in infused mice by pcDNA3 1(-)-flaA suggested that the expression level of IL-2 and IFN gamma were increased compared to the IL-4 via simulation of Th1. Also, the expression of the flaA gene in tissue samples was decreased 45 days after the last injection. Therefore, it can be concluded that the pcDNA3.1(-)-flaA recombinant vector together with chitosan nanoparticles has the ability to stimulate the immune system and it can be investigated as a cost-effective method to control the H. pylori disease in a human in further studies.