Salmonella Flagellin Enhances Immunity of Inactivated Avian Influenza Vaccine

To test whether Salmonellaflagellin can be as potent adjuvant in preparation of novel avian influenza vaccine,in this study,flagellins of Salmonella gallinarum were prepared and purified by using hydrochloric acid decomposition method.The vaccine developed by the complex of flagellins and inactivated H9N2 subtype avian influenza virus was evaluated by animal experiments.The results showed that this adjuvented vaccine induced significant IgA level from the mucous of the respiratory tract and plasma after being inoculated into chickens via either intranasal or intramuscular route,compared with inactivated avian influenza virusalone,although Salmonellaflagellins didn't improve hemagglutinin inhibition(HI)antibody in vaccinated chickens.The challenge experiments indicated that intranasal immunization with Salmonellaflagellin adjuvanted vaccine induced 53.3%of protection,but no protection(0/15)was achieved from the same inoculation route with inactived AIV alone.However,intramuscular immunization with combination of flagellins and inactivated AIV exhibited 60% of protection,which was greater than that with inactivated AIV alone(30%).It demonstrated that Salmonellaflagellin could enhance protection efficacy of inactivated AI vaccine.