Immunogenicity and protection against Haemophilus parasuis infection after vaccination with recombinant virulence associated trimeric autotransporters (VtaA)

Abstract: Haemophilus parasuis is the etiological agent of Glässer''s disease in swine, characterized by fibrinous polyserositis, polyarthritis and meningitis. The lack of a vaccine against a broad spectrum of strains has limited the control of the disease. Recently, virulence associated trimeric autotransporters (VtaA) were described as antigenic proteins of H. parasuis. In this study 6 VtaA were produced as recombinant proteins and used to immunize snatch-farrowed, colostrum-deprived piglets. Immunized animals developed specific systemic and mucosal antibodies. The protective capacity of the anti-VtaA antibodies was evaluated by the inoculation of 3×108 or 6×106 colony forming units (CFU) of the highly virulent strain Nagasaki. Vaccinated animals had a delayed course of disease and 33 or 57%, respectively, of the animals survived the lethal challenge. The partial protection achieved with the recombinant VtaA supports their potential as candidates to be included in future vaccine formulations against H. parasuis. [Copyright &y& Elsevier]