In silico experiment with an-antigen-toll like receptor-5 agonist fusion construct for immunogenic application to Helicobacter pylori
Mohamad Ali Haghighi1, Ashraf Mohabati Mobarez1, Ali Hatef Salmanian2, Mohamad Moazeni3, Mohamad Reza Zali4, Mehdi Sadeghi5, Jafar Amani6
1 Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
2 Department of Plant Biotechnology, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
3 Department of Immunology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
4 Gastroenterology and Liver Disease Research center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
5 Department of Biochemistry National Institute of Genetic Engineering and Biotechnology, Baqiyatallah Medical Science University, Tehran, Iran
6 Applied Microbiology Research Center, Baqiyatallah Medical Science University, Tehran, Iran
Ashraf Mohabati Mobarez
Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran
Source of Support: Tarbiat modares University,, Conflict of Interest: None
Backgrounds: Helicobacter pylori colonize the gastric mucosa of half of the world's population. Although it is classified as a definitive type I carcinogen by World Health Organization, there is no effective vaccine against this bacterium. H. pylori evade the host immune response by avoiding toll-like detection, such as detection via toll-like receptor-5 (TLR-5). Thus, a chimeric construct consisting of selected epitopes from virulence factors that is incorporated into a TLR-5 ligand (Pseudomonas flagellin) could result in more potent innate and adaptive immune responses.
Materials and Methods: Based on the histocompatibility antigens of BALB/c mice, in silico techniques were used to select several fragments from H. pylori virulence factors with a high density of B- and T-cell epitopes.
Results: These segments consist of cytotoxin-associated geneA (residue 162-283), neutrophil activating protein (residue 30-135) and outer inflammatory protein A (residue 155-268). The secondary and tertiary structure of the chimeric constructs and other bioinformatics analyses such as stability, solubility, and antigenicity were performed. The chimeric construct containing antigenic segments of H. pylori proteins was fused with the D3 domain of Pseudomonas flagellin. This recombinant chimeric gene was optimized for expression in Escherichia coli. The in silico results showed that the conserved C- and N-terminal domains of flagellin and the antigenicity of selected fragments were retained.
Discussion: In silico analysis showed that Pseudomonas flagellin is a suitable platform for incorporation of an antigenic construct from H. pylori. This strategy may be an effective tool for the control of H. pylori and other persistent infections.