Bordetella parapertussis, infective phenotype characterization and its relevance in vaccine development

ALVAREZ HAYES, JIMENA; SCHMIDT FRANK ; LAMBERTI YANINA; AYALA, MIGUEL; VOLKER UWE; OVIEDO, JUAN MARCOS; FABRICIO MASCHI; SURMANN KRISTIN; ALVAREZ HAYES, JIMENA; LABORDE, JUAN MARTIN; SCHMIDT FRANK ; OVIEDO, JUAN MARCOS; AYALA, MIGUEL; RODRIGUEZ, MARÍA EUGENIA; SURMANN KRISTIN; LABORDE, JUAN MARTIN; RODRIGUEZ, MARÍA EUGENIA; LAMBERTI YANINA; VOLKER UWE; FABRICIO MASCHI

Mar del Plata

Congreso; LXIV REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INMUNOLOGÍA; 2016

Sociedad Argentina de Inmunología

Bordetella parapertussis (Bpp) is one of the causes of whooping cough whose incidence has been rising in the last decade. Opsonic antibodies are necessary to eliminate this pathogen. The only opsonins induced by current acellular pertussis (aP) are those directed against pertactin. aP is composed of three antigens common to both species FIM, FHA and Prn. According to previous studies aP don?t induce proper immunity against Bpp. Partially because Prn isn?t exposed on the surface of Bpp due to the shielding properties of the O antigen of this species. Iron starvation is a critical stress a bacteria has to overcome during infection and induces deep changes in bacterial phenotype also at antigen level. In this study we used shotgun proteomics to study this bacterium and the phenotype induced under iron starvation. We found that Fim expressed by Bpp is different from that expressed by Bp and there is not cross reactivity between them. On the other hand, under iron starvation FhaC, a protein necessary for FHA exportation is downregulated determining a decrease in surface-bound FHA as confirmed by western blot. According to these results under physiological conditions Bpp should be more effective in avoiding aP induced immunity than expected. However, we also found that the lack of iron induced a significant decrease of wbmM expression which eventually introduced changes in the O-antigen molecule as confirmed by electrophoresis analysis. This change seemed to induce variations in the shielding property of the O antigen since antibodies directed against Prn were found able to attach to iron starved Bpp more efficiently as determined by ELISA. Accordingly, in vivo studies showed that aP induced significantly higher protection against the iron starved Bpp than that reported for the iron replete phenotype. Since the infective phenotype is iron starved our results suggest that might be easier than expected to improve the protective capacity of current whopping cough vaccines