LAUSR

Background Pertussis is a current contagious bacterial disease caused by Bp. Given the prevalence of pertussis, developmentof new vaccines is important. The goal of this study was to evaluate and compare the expression of main virulence factors from Bp predominant local isolates to that of the same factors in the OMVs from circulating isolates of Bp with predominant profile, as well as to assess its physicochemical properties as a probable vaccine candidate. Methods The physicochemical features of the prepared OMVs were analyzed by electron microscopy and SDS-PAGE. The presence of PTX, PRN, FHA virulence factors was confirmed by Western blotting. BALB/c mice (n =21) immunized with characterized OMVs were challenged intranasally with sublethal doses of Bp, to examine their protective capacity. Results Electron microscopic examination of the OMVs indicated vesicles within the range of 40 to 200 nm. SDS-PAGE and Western blotting demonstrated the expression of all three main protective immunogens (PTX, PRN, FHA), prevalent in the predominant, challenge, and vaccine strains, and OMVs of the predominant IR37 strain and BP134 vaccine strain. Significant differences were also observed between immunized animals and the control group (p < 0.001). Conclusion The results demonstrated that the OMVs obtained from circulating isolates with the predominant profile may constitute a highly promising vaccine quality and be proposed as a potential basic material for the development of new pertussis vaccine candidate.