Bfra-loaded nanoparticles confer protection against paratuberculosis infection.

Paratuberculosis is a chronic wasting disease of granulomatous enteritis in ruminants caused by Mycobacterium avium subsp. paratuberculosis (M. paratuberculosis, MAP) resulting in heavy economic losses to dairy industries worldwide. Currently, commercial vaccines were not effective in preventing pathogen shedding and were reported with serious side effects. To develop a novel and smarter paratuberculosis vaccine, we utilized PLGA nanoparticles encapsulating the Bfra antigen (Bfra-PLGA NPs). We observed that mice vaccinated with Bfra-PLGA NPs exhibited an enhanced secretory IFN-γ, CD4+ T cells response and antibody IgG against MAP infection. In addition, secretions of the inflammatory cytokine TNF-α and IL-10 were increased following treatment with Bfra-PLGA NPs. A significant reduction in bacterial load was observed in the livers and spleens of animals vaccinated with Bfra-PLGA NPs. Furthermore, Bfra-PLGA NPs were effective to alleviate the pathological lesions of livers in mice. Overall, our approach provides a rational basis for employing PLGA nanoparticles to develop improved vaccines that induced protective immunity against paratuberculosis. [ABSTRACT FROM AUTHOR]