CONICET | Buscador de Institutos y Recursos Humanos

ADJUVANT PROPERTIES OF OUTER MEMBRANEVESICLES DERIVED FROM BORDETELLA PERTUSSIS.Rudi, E, Gaillard ME, Castuma C, and Hozbor DLaboratorio VacSal. Instituto de Biotecnología y Biología Molecular.Facultad de Ciencias Exactas. Universidad Nacionalde La Plata. CONICETPertussis is a vaccine preventable respiratory disease which is currentlyconsidered a serious health problem. We have designed anovel pertussis vaccine candidate based on outer membrane vesiclesderived from B. pertussis (OMVsBp) that is safe, highly immunogenic,and protective in mouse model. OMVsBp includes awide range of immunogens and PAMPs. Since these PAMPs couldhave adjuvant properties by themselves we wonder which is thecontribution of the OMVs? integrity on their adjuvant properties. Toaddresses this aspect, we perform comparative studies between intactOMVs (OMVi) and mechanically disrupted OMVs (OMVD). BothOMVs were isolated and treated with standardized protocols andformulated with Fim3, a poorly immunogenic protein that is not presentin OMVs. Fim3 was expressed and purified from a recombinantEscherichia coli strain. An immunization scheme was performed inBalb/C mice consisting of two immunizations with 0,75 μg of OMVi orOMVD combined with Fim3 (10 μg). Non immunized mice and OMVi,OMVD, or Fim3 immunized mice were used as control. Postvaccinationserum samples were obtained, and a-Fim3 antibody levels wereevaluated by Immunoblot and ELISA. By performing these experiments,we detected that OMVi+Fim3 induces higher antibody responsea-Fim3 than OMVD+Fim3 (OMVi+Fim3: 3257 ± 264,5 vs OMVD+Fim3: 236,05 ± 56,63). Moreover, OMVi+Fim3 induced higherlevels of a-Fim3 antibodies in comparison with that detected in Fim3immunized mice (Fim3: 53,43 ± 11,97). Consistent with the ELISAresults, serum samples obtained from OMVi+Fim3 immunized miceshown the highest reactivity against Fim3 in Immunoblot. The resultspresented here point out the relevance of OMVsBp integrity forits adjuvant properties.