Immunoinformatics Insights into the Internalin A and B Proteins to Design a Multi-Epitope Subunit Vaccine for L. monocytogenes

As an important foodborne pathogen, Listeria monocytogenes is associated with high hospitalization and case-fatality rates. Outbreaks due to foods contaminated with this pathogen continue to occur globally. A suitable vaccine can protect susceptible populations against this infection. In this study, two essential surface proteins (internalins A and B) of L. monocytogenes which are used for the entry of bacteria into different host cells were selected as candidates for the design of a multi-epitope protein vaccine by powerful immunoinformatics servers and soft wares. Epitopes were selected based on scores of antigenic properties, cytokine induction potential and allergenicity. To construct the multi-epitope vaccine, the selected cytotoxic T lymphocytes epitopes were linked together by an AAY linker, whereas GPGPG linkers were used to link the helper T lymphocytes epitopes. Physiochemical characterization, and the secondary and tertiary structures of the protein vaccine were determined. After refinement, validation and energy minimization, the immune simulation was conducted by the C-ImmSim server. The obtained results showed that the designed vaccine is stable and could effectively trigger the immune response. Overall, the results of this study demonstrated that the designed vaccine is specific, antigenic, non-allergenic, and can effectively prevent L. monocytogenes infections. Further clinical trials are required to check the efficacy of this vaccine