Protective capacity of the humoral response induced by a novel acellular pertussis vaccine candidate.

ZURITA MARÍA EUGENIA; GAILLARD M. EMILIA; BOTTERO DANIELA; MORENO GRISELDA; CARRIQUIRIBORDE FRANCISCO; DAVID SABATER MARTINEZ; ERREA AGUSTINA; CASTUMA CELINA; RUMBO MARTÍN; DANIELA F. HOZBOR,

BUENOS AIRES

Simposio; 11th International Bordetella Symposium; 2016

Background. Based on the current epidemiologic pertussis situation, new generation of vaccines to improve the control of the disease has been proposed. In this context we have developed a vaccine based on Outer Membrane Vesicles (OMVs), derived from Bordetella pertussis. This vaccine candidate elicits protective capacity in mice model conferring long-lasting immunity. Objective. Characterize the humoral immune response induced by OMVs-based vaccine (TdapOMVBp) in comparison with current commercial vaccines. Materials and Methods. To obtain immune sera, groups of 5 mice were i.p. immunized with TdapOMVBp (3ug of protein/dose) or with commercial wP and aP vaccines (1/10 human dose). The levels of specific total IgG and IgG1 and IgG2a isotypes were determined by ELISA. The contribution of humoral immune response was assessed by in vivo passive transfer experiments and by in vitro opsonophagocytosis assays using RAW murine macrophages. Results. Significant amounts of total IgG antibodies were detected in sera from TdapOMVBp immunized mice with a high IgG2a/IgG1 ratio (1.25±0.43); suggesting a mixed Th1/Th2 profile. Interestingly, the transfer of TdapOMVBp-immune sera led to protection against B. pertussis, reducing in approximately 2.5 logs the UFC recovered from lungs of challenged mice in comparison with those recovered from non-immunized mice. In agreement with these results, we observed that bacteria were efficiently opsonized by TdapOMVBp-immune sera. Conclusion. The results presented here show that TdapOMVsBp elicits a humoral immune response which is involved in protection as it is observed for current commercial vaccines.