Antibodies against fimbrial subunits included in acellular vaccines do not have biological activity against Bordetella parapertussis

GORGOJO, JUAN PABLO; OVIEDO, JUAN MARCOS; 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

Resurgence of whopping cough is partially due to an increase in the incidence of B. parapertussis (Bpp) infections whose start concurs with the replacement of whole cell vaccines by acellular vaccines (AV). AV are formulated with B. pertussis (Bp) antigens some of which are homologous to those produced by Bpp. Previous studies, however, showed that most antibodies induced by AV fail to protect against Bpp due to the presence of the O antigen (AgO) on the Bpp surface that impairs antibody access to shared antigens. However, controversial results have been reported regarding the role of AV induced anti-fimbria antibodies against Bpp. Fimbriae are proteins exposed on the surface of Bpp and due to its length it is very unlikely shielded by the AgO. Antibodies against these antigens have shown to be protective against Bp but little is known about the cross protection induced by Bp fimbrial subunits 2 and 3 (Fim2/3) against Bpp. In this study we examined the potential of Fim2/3 as vaccine antigens against Bpp infections. To this end, the biological activity of antibodies induced by a vaccine formulated by Bp Fim2/3 was evaluated against Bpp. Whole cell ELISA showed that anti-Fim2/3 antibodies poorly recognize Bpp. Functional assays showed that these antibodies do not agglutinate Bpp and fail to inhibit Bpp attachment to epithelial cells. The AgO was found not involved in the absence of antibody recognition, agglutination activity or inhibition of Bpp attachment to epithelial cells, as determined by the use of an AgO mutant. Proteomic studies showed that Bpp do not express Fim2/3 and bioinformatics analysis suggested that the lack of biological activity of anti-Fim2/3 antibodies against Bpp might be due to a low degree of homology with Bpp fimbriae. Together with previous results this study demonstrates that none of the components of current acellular vaccines protect against Bpp stressing the need for a new generation of preventive strategies to control whooping cough.