in vitro Quality evaluation of avian influenza subtype h9n2 Oil-Emulsion Vaccines

The use of vaccines in poultry to control avian influenza viruses (AIVs), especially mildly pathogenic avian influenza viruses, has been increased in recent years; thus, regarding the characteristic of AIVs, it is important to evaluate the quality of vaccines with an appropriate and rapid method. The aim of the present study was to investigate the quality of three commercially available oil-emulsion AIVs (subgroup H9N2) vaccines via in-vitro assessment. Viral antigens of the vaccines were recovered by aqueous partition method and the amounts of extracted total protein and recovered hemagglutination (HA) activity were determined and compared with the immune system responses of chickens to the vaccines. It has been shown that the amount of recovered total protein and activity of the recovered HA were different among vaccines with the same dose. Meanwhile, chickens showed different immune system responses to the vaccines. We have shown poor quality for two vaccines and high quality for one which can be attributed to their viral protein density.