PROTECTIVE CAPACITY OF OUTER MEMBRANE V E S I C L E S D E R I V E D F R O M B O R D E T E L L A BRONCHISEPTICA.

BOTTERO D.; GAILLARD M.E.; HOZBOR D.

Simposio; 11th International Bordetella Symposium; 2016

Though vaccines for Bordetella bronchiseptica (Bb) zoonotic pathogen have been in  common use since their development in the late 1970s many questions related to the efficacy and the longevity of vaccine-induced immunity remain unanswered. New vaccines, better characterized, seems to be neededObjective: To design and characterize a new vaccine against Bb based on outer membrane vesicles derived from this pathogen (OMVsBb).Material and Methods: Based on our experience on OMVs isolation from B. pertussis and B. parapertussis, here we obtained OMVsBb from Bb strain 9.73. TEM microscopy and immunoblots were used to examine the quality of our OMVsBb preparations. To test the protective capacity of OMVsBb-based vaccine, the murine respiratory model of infection was used. Results: OMVsBb with a mean size of 80nm were obtained. When these characterized OMVsBb were used in the murine model as vaccine against the infection caused by Bb isolates obtained either from rabbit or human, significant differences between immunized animals and the PBS treated groupwere observed (p < 0.001). Humoral response induced byOMVsBb vaccine appeared to be involved in the protective capacity as it was demonstrated by sera transfer assay. Adequate elimination rates were observed in mice immunized with OMVsBb-sera but not with naïve sera (p <0.001). The contribution of virulence factors in OMVsBbmediated protection was also investigated. Interestingly, we observed that the protective ability of OMVsBb obtained  from a Bb strain, which does not express any of the virulence factors but expresses the avirulent phenotype; was comparable to that of OMVs obtained from virulent Bb phase.Conclusion: Here we demonstrated that OMVsBb are protective in the murine model of infection. Protection conferred by OMVsBb seems to be at least mediated by the humoral immune response. Moreover, the presence of virulence factors on OMVsBb is not essential for the protective capacity conferred by OMVsBb.