The immunological response of Salmonella typhi protein subunits (Outer membrane protein 36 kDa, fimbriae 36 kDa, and flagellin) as a candidate for oral typhoid vaccine

Salmonella typhi infection leads to typhoid fever on a global scale, particularly in developing countries. The currently available vaccine has its drawbacks that sporadically render a concern. Thereby, a new proffered vaccine needs to be proposed, such as a vaccine from bacteria’s protein subunits. Vaccine subunits contain only the antigenic portion of the pathogen needed to elicit a protective immune response. This research aims to assess the immunogenic potential of the protein subunit of Salmonella typhi antigen in enhancing cellular and mucosal immune responses, so it can be applied as a candidate for the typhoid fever vaccine. The Salmonella typhi protein subunits used in this research are outer membrane protein (OMP), fimbriae, and flagellin. The efficacy of the vaccine was confirmed by its production of CD4+ and CD8+ T Cells for cellular immunity response, and its production of SIgA concentration for humoral immunity response. CD4+ and CD8+ T cell examination was performed by flow cytometry analysis, while SIgA confirmation was checked by ELISA method. The result shows that, based on its immunity responses, compared with OMP, fimbriae, and flagellin have more potential to be used as a vaccine candidate against typhoid fever.