BORDETELLA PARAPERTUSSIS, INFECTIVE PHENOTYPE CHARACTERIZATION AND ITS RELEVANCE IN VACCINE DEVELOPMENT

OVIEDO, J; ALVAREZ HAYES, J; LAMBERTI, Y; SURMANN, K; SCHMIDT, F; VÖLKER, UWE; LABORDE, JM; AYALA, M; MASCHI, F; RODRIGUEZ, ME.

Congreso; LXIV Reunión Anual de la Sociedad Argentina de Inmunología (SAI); 2016

Bordetella parapertussis (Bpp) is one of the causes of whoopingcough 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 threeantigens common to both species FIM, FHA and Prn. Accordingto previous studies aP don?t induce proper immunity against Bpp.Partially because Prn isn?t exposed on the surface of Bpp dueto the shielding properties of the O antigen of this species. Ironstarvation is a critical stress a bacteria has to overcome duringinfection and induces deep changes in bacterial phenotype also atantigen level. In this study we used shotgun proteomics to studythis bacterium and the phenotype induced under iron starvation.We found that Fim expressed by Bpp is different from that expressedby Bp and there is not cross reactivity between them. Onthe other hand, under iron starvation FhaC, a protein necessary for FHA exportation is downregulated determining a decrease insurface-bound FHA as confirmed by western blot. According tothese results under physiological conditions Bpp should be moreeffective in avoiding aP induced immunity than expected. However,we also found that the lack of iron induced a significant decreaseof wbmM expression which eventually introduced changes in theO-antigen molecule as confirmed by electrophoresis analysis. Thischange seemed to induce variations in the shielding property ofthe O antigen since antibodies directed against Prn were foundable to attach to iron starved Bpp more efficiently as determinedby ELISA. Accordingly, in vivo studies showed that aP inducedsignificantly higher protection against the iron starved Bpp thanthat reported for the iron replete phenotype. Since the infectivephenotype is iron starved our results suggest that might be easierthan expected to improve the protective capacity of current whoppingcough vaccines.