The Humoral and Cellular Immune Response Characteristic of Propolis Flavonoid Used as Adjuvant to Inactivated PPV Vaccine in Sows

The present study was conducted to assess the effects of propolis flavonoid used as adjuvant on the immune response of Landrace-Yorkshire hybrid sows immunized with an inactivated vaccine of porcine parvovirus (PPV). Thirty Landrace-Yorkshire hybrid sows were randomly assigned to one of 3 groups, and the sows in two adjuvant groups were intramuscular injected PPV vaccine with 2.0 mL propolis flavonoid adjuvant (PA) or oilemulsion adjuvant (OA), respectively. After that, serum hemagglutination inhibition antibody titers, specific IgM, IgA and IgG subclasses were measured to estimate the humoral immunity for the adjuvant effects of propolis flavonoid, as well as peripheral lymphopoiesis activity, and lymphocyte factor concentrations of Th1 and Th2 for cellular immune responses. Results indicated in a significant enhancing effect of PA on concentrations of IgM, IgG2, IgG3, IL-2 and IFN-γ comparing to OA. Especially in improving the effect of Th1 cellular immune response, the PA was superior to OA. These findings suggested that PA can significantly enhance the immune responses against PPV vaccine and could be exploited to a new PPV vaccine in sows.