Oral Administration with Recombinant Attenuated Regulated Delayed Lysis Vaccines Protecting against Kidney Abscess Formation.

Abscess formation is one of the main symptoms of infection. It is very important to inhibit abscess formation for preventing persistent infection. To find a feasible solution, the live oral vaccines delivering antigens, rEsxAB and rHla, were constructed, which were based on the attenuated regulated delayed lysis subspecies Serovar Typhimurium strain χ11802, and the inhibiting effect on abscess formation was evaluated in mice kidneys. As the results showed, after oral administration, humoral immunity was induced via the mucosal route as the antigen-specific IgG in the serum and IgA in the intestinal mucus both showed significant increases. Meanwhile, the production of IFN-γ and IL-17 in the kidney tissue suggested that Th1/Th17-biased cellular immunity played a role in varying degrees. After challenged intravenously (i.v.) with USA300, the χ11802(pYA3681-)-vaccinated group showed obvious inhibition in kidney abscess formation among the vaccinated group, as the kidney abscess incidence rate and the staphylococcal load significantly reduced, and the kidney pathological injury was improved significantly. In conclusion, this study provided experimental data and showed great potential for live oral vaccine development with the attenuated regulated delayed lysis Typhimurium strains against infection.