Study of antigens selectively expressed in the infective phenotype of Bordetella pertussis

ALVAREZ HAYES, J; LAMBERTI, Y.; PEREZ VIDACOVIKS, M. L.; RODRIGUEZ, ME

Rosario

Congreso; V Congreso Argentino de Microbiologia General; 2008

The low efficacy in preventing colonization of the pertussis vaccines in use have led to disease re-emergence. Re-emergence of pertussis may be explained by several factors: an increase of asymptomatic adult carriers, expansion of strains with certain antigenic variations among others. The iron limitation is a condition that an infecting microorganism face inside the host. By mean of comparative proteomic and bioinformatics we identified antigens that although present in the infective phenotype are absent in current vaccines. Among them we selected two, supposedly exposed on the surface of the bacteria, to study their potential as vaccine components, namely, a putative iron binding protein, and a putative exported protein with remarkably high expression under physiological conditions. The proteins proved antigenic in mice and the induced antibodies recognized the respective native protein on surface of Bordetella pertussis, with confirmed overexpression in bacteria adapted to the iron limitation.  When tested in vitro both kind of antibodies displayed aggluttinin and opsonic activity, the main biological activities against B. pertussis colonization. We then checked whether the genes are conserved among circulating strains by screening a panel of clinical isolates by PCR. Importantly, we found them present in all the strains tested. Taken together our results point at these antigens as promising new vaccine candidates