Bordetella pertussis filamentous hemagglutinin delivered by mucosal routes enhances immunoglobulin levels in serum and mucosal fluids

Free Bordetella pertussis filamentous hemagglutinin (FHA) can act as an adjuvant for mucosally administrated antigens. Here, we show that independently of the adjuvant properties of FHA toward an unrelated antigen, total IgG or IgA concentrations in serum and mucosal fluids are enhanced by the administration of FHA. Oral administration of FHA increases both total IgG concentrations in serum and total immunoglobulin concentrations in intestinal lavages. Nasal administration of FHA increases total IgA concentrations in broncho-alveolar lavages. FHA induces Langerhans cell recruitment and MIP-3α mRNA expression within hours after administration. These observations shed a new light on the potential molecular mechanisms of FHA-induced adjuvanticity.