Novel iron regulated antigen protects against both causative agents of whooping cough.

OVIEDO, JUAN MARCOS; ALVARES HAYES, JIMENA; VALDEZ, HUGO; LABORDE, JUAN; MASCHI, FABRICIO; AYALA, MIGUEL; RODRIGUEZ, MARIA EUGENIA

Buenos Aires

Congreso; Reunión conjunta de sociedades de biociencias. LXIV Reunión Anual de la Sociedad Argentina de Inmunología (SAI).; 2017

Sociedad Argentina de Inmunología

Whooping cough is a highly contagious infectious disease caused by Bordetella pertussis (Bp) and Bordetella parapertussis (Bpp).According to previous studies current acellular pertussis vaccine induces not only low protection against Bp. but also no protection against Bpp. New protective antigens are needed to improve the efficacy of this vaccine against both species. Through the study of proteins induced under physiological conditions, such as iron starvationour group has identified and cloned two novel antigens protective against B. pertussis. Interestingly, the sequence of these antigens are highly conserved among both previously mentioned Bordetella species, and even more than the sequence of pertactin and FhaB, antigens included in acellular vaccines. In the present work, we studied one of this antigens (Bp1605, AfuA) as a protective immunogen against Bpp. Using western blot and ELISA tests we confirmed that Bordetella parapertussis expresses a homolog of AfuA and that, as found for B. pertussis, it is an iron regulated, surface exposed protein, expressed during infection. This study also showed that antibodies induced by immunization with the recombinant AfuA cloned from Bp (rAfuA) were able to opsonize B. parapertussis and promote bacterial uptake by neutrophils. The inefficacy of current acellular vaccines against Bpp has been attributed to the effect of the O-antigen, absent in Bp. The O-antigenhas been described as a shield that protects Bpp from antibody recognition on the bacterial surface. We here found that the O-antigen has no influence on the recognition of the antibodies raised against AfuA. Accordingly, we found that rAfuA confers protection against B. parapertussis infection in a mouse intranasal challenge model. Taken together, these results point at AfuA as an excellent vaccine candidate for a new generation of acellular vaccines protective against both whooping cough causative agents.