Membrane vesicles derived from bordetella bronchiseptica: active constituent of a new vaccine against infections caused by this pathogen

BOTTERO, DANIELA; ZURITA, MARÍA EUGENIA; GAILLARD, MARÍA EMILIA; BARTEL, ERIKA; VERCELLINA, C; HOZBOR, DANIELA

APPLIED AND ENVIRONMENTAL MICROBIOLOGY

AMER SOC MICROBIOLOGY

Lugar: Washington; Año: 2017

0099-2240

Bordetella bronchiseptica, a Gram-negative bacterium, causes chronic respiratory-tract infections in a wide variety of mammalian hosts-humans included, albeit rarely. We recently designed B. pertussis and B. parapertussis experimental vaccines based on outer-membrane vesicles derived from each pathogen and obtained protection against the respective infections in mice. Here, we demonstrate that outer-membrane vesicles derived from virulent-phase B. bronchiseptica (OMVBbvir+) protect mice against sublethal infection from different B. bronchiseptica strains, two isolated from farm animals and one from a human. In all infections, we observed that the B. bronchiseptica load was significantly decreased in the lungs of the vaccinated animals: the lung-recovered colony-forming units diminished by at least 4 logs below those detected in the lungs of nonimmunized animals (p<0.001). In the OMVBbvir+-immunized mice, we detected IgG-antibody titers against B. bronchiseptica whole-cell lysates along with an immune serum having bacterial-killing activity that both recognized B. bronchiseptica lipopolysaccharides and polypeptides such as GroEL and OMPc and conferred an essential protective capacity against B. bronchiseptica infection as detected by passive in-vivo-transfer experiments.             Stimulation of cultured splenocytes from immunized mice by OMVBbvir+ resulted in the presence of IL-5, INF-γ, and IL-17 production; indicating that the vesicles induced a mixed Th2, Th1, and Th17 T-cell-immune-response profile. We detected by adoptive transfer assay that spleen cells from OMVBbvir+-immunized mice also contributed to the observed protection against B. bronchiseptica infection. Outer-membrane vesicles from the avirulent-phase B. bronchiseptica and the resulting induced immune sera were also able to protect mice against B. bronchiseptica infection.