Neutralizing antibody level induced and anaphylaxis of influenza A H1N1 virus split vaccine in animals

Objective To evaluate the neutralizing antibody level induced and anaphylaxis of influenza A H1N1 virus split vaccine in animals. Methods Kunming mice were divided randomly into seven groups,10 for each,and injected i.p.with three batches of influenza A H1N1 virus split vaccine at dosages of 15,30 and 45 μg / 0. 5 ml,three batches of seasonal influenza H1N1 virus split vaccine at dosages of 15,30 and 45 μg / 0. 5 ml and 0. 5 ml PBS(negative control)respectively,and boosted 21 d later. Serum samples were collected before immunization,21 d after primary immunization and 14 d after booster immunization respectively,and determined for neutralizing antibody titer by fixed virus-diluted serum method. Guinea pigs were divided randomly into four groups and injected i.p. with three batches of influenza A H1N1 virus split vaccine and PBS(negative control)respectively,0. 5 ml for each,every other day for 3 times,then challenged i.v. with 1. 0 ml of vaccine of the same batches on days 14 and 21 after the first immunization and observed for anaphylaxis. Results The neutralizing antibody titers in sera of mice 21 d after primary immunization with influenza A H1N1 virus split vaccine at dosages of 15,30 and 45 μg were 47. 9,113. 5 and 319. 9 times of those before immunization and those in negative control group,which were dose-dependent. However,the neutralizing antibody titers14 d after booster immunization with influenza A H1N1 virus split vaccine at various dosages were significantly higherthan those 21 d after primary immunization and those after booster immunization with seasonal influenza A virus split vaccine,which were also dose-dependent. No anaphylaxis was observed in guinea pigs immunized with influenza A H1N1 virus split vaccine at any dosages. Conclusion Influenza A H1N1 virus split vaccine induced protective neutralizing antibody, which showed no anaphylaxis in guinea pigs.