In Process Quality Control Factors Affecting Efficacy of Avian Influenza (H5N1) Vaccine

Avian Influenza (AI) is causing heavy economic losses in domestic poultry all over the world. It is caused by a highly pathogenic virus H5N1. The present study was aimed at assessing the quality control parameters during the process of vaccine production. The virus was recovered from lungs, trachea and fecal contents of the infected birds in chicken embryos. Binary ethylenimine (5mM) inactivated the virus with in 16 hours of incubation at 25°C. The AI vaccine without adjuvant induced poor anti-AIV-HA antibody titer (3.5 GMT) in the vaccinated broilers. The vaccine containing aluminum hydroxide gel (AHG) induced the antibody response (36.8 GMT) that reached the peak level on 18 days post priming and declined thereafter. Montanide ISA 70 based AI vaccine induced increasing trend of the antibody titer (90.5 GMT) on 42 days of age. Boosting of the birds primed with AHG-AIV vaccine improved the antibody response (111.4 GMT on 42 days of age), while boosting of birds primed with montanide based AIV showed undetectable effect. The vaccines containing higher biological titer induced higher antibody titer in the vaccinated broilers. Serial passages of the AIV through embryos improved it’s HA and biological titer but tremendously decreased its antigenicity. It is concluded that use of the montanide based AIV vaccine prepared from it’s passage number <4, could be an effective way of the immuno-prophylaxis.