In vivo testing of novel vaccine prototypes against Actinobacillus pleuropneumoniae

摘要: Actinobacillus pleuropneumoniae (A. pleuropneumoniae) is a Gram-negative bacterium that represents the main cause of porcine pleuropneumonia in pigs, causing significant economic losses to livestock industry worldwide. A. pleuropneumoniae, as majority bacteria, excrete vesicles from its outer membrane (OM), accordingly defined (OMVs). Thanks their antigenic similarity OM, OMVs have emerged promising tool vaccinology. In this study we describe vivo testing several vaccine prototypes for prevention infection by all known serotypes. Previously identified candidates, recombinant proteins ApfA and VacJ, administered individually or various combinations with OMVs, were employed vaccination strategies. Our data show addition formulations significantly increased specific IgG titer against both VacJ immunized animals, confirming previously postulated potential adjuvant. Unfortunately, antibody response raised did not translate into an effective protection infection, none groups following challenge showed lower degree lesions than controls. Interestingly, quite opposite was true, animals highest titers also ones bearing most extensive lungs. These results shed new light on pathogenicity, suggesting antibody-mediated cytotoxicity host immune may play central role development typically associated infections.