TWO ANTIGENS IDENTIFIED BY IMMUNOPROTEOMICS PROVED TO BE GOOD CANDIDATES FOR A NEW GENERATION OF PERTUSSIS ACELLULAR VACCINES

ALVAREZ HAYES, JIMENA; ERBEN, ESTEBAN; RODRIGUEZ, MARÍA EUGENIA

Dublin

Congreso; 10th International Bordetella Symposium; 2013

Bordetella pertussis is the etiologic agent of whooping cough, an illness which has persisted worldwide, despite universal vaccination. The highest incidence of the disease among adolescents and adults indicates the need for a universal booster vaccination with acelular vaccines for this population. The existence of circulating strains of B.pertussis not expressing two of the main vaccine antigens highlights the need to find new vaccine candidates. An effective way to improve pertussis control may comprise updating current vaccines by including antigens that are expected to be present in the infective phenotype. Antigenic proteins whose expression is induced under physiological conditions might be a good option. The lack of iron is an environmental stress that human pathogens have to face during infection. Several observations suggest that B. pertussis is iron-starved inside its natural human host and responds by expressing a number of vital iron uptake systems. With the aim of identifying protective antigens, we have focused on proteins that might be necessary for this nutrient acquisition during colonization. By mean of immunoproteomic analysis, we identified two antigenic proteins potentially involved in iron acquisition. We had previously demonstrated that one of them, namely IRP1-3, is protective against pertussis infection in mice. Herein, we showed that the other protein, named AfuA (BP1152), is a highly antigenic protein exposed on the bacterial surface, expressed during infection and conserved among clinical isolates. Immunization of mice with the recombinant AfuA induced opsonophagocytic antibodies and cellular immune response, which could explain the protection against B. pertussis infection conferred by immunization with rAfuA in the murine infection model. Furthermore, the addition of rAfuA and/or rIRP1-3 proteins to the commercial three pertussis component acellular vaccine improved its level of protection, probably because their ability to induced opsonic antibodies. Thus, new acellular pertussis vaccines formulations that included these proteins could be more efficient in protection against infection.