Immune Responses To Avian Influenza Virus Inactivated Vaccine And Protection Of It In Diabetic Mice

Avian influenza (AI) is a highly contiguous acute disease caused by influenza A virus in birds. The avian influenza virus , a member of Orthomyxoviridae family, is responsible for AI. Nowadays , AIV have already spread worldwide. Every disastrous outbreak event of AI has made great economic loss.In the late 1990s, H5N1 and H9N2 avian influenza viruses transmitted from birds to humans .Since then, there were continuous reports about H5N1 influenza outbreaks in many countries and the isolations of H9N2 from humans which provided evidence that AIV have the ability to infect human. Diabetes is a metabolic disease that may cause abnormality of immunologic function which result in the increased risk of viral and bacterial infections. Thus, they may become the first victims and the mixing vessel for generation of new viruses. Vaccination is an important preventive strategy for viral infectious diseases among persons with diabetes. We should pay attention to the development of avian influenza vaccines and provide well protection for diabetic.In our experiment, H9N2 avian influenza virus was adapted to BALB/c mice by lung-to-lung passage. We have prepared wholevirus inactivated vaccine and established a stable and persist model of type I diabetes by a single injection of STZ at a high dose in male mice. BALB/c mice both diabetic and healthy, were immunized once or twice with H9N2 virus inactivated vaccine. Four weeks later, the mice were challenged with a lethal dose(20×LD₅₀) of H9N2 AIV. The protective effect of vaccine was evaluated by induction of serum antibody response, body weight loss, survival rate and lung virus titers. The result showed that the antibody responses in diabetic mice were inhibited. In diabetic mice , immunization once with high dose or twice with low dose of vaccine provided effective protection, and immunization twice with high dose provided a full protection against lethal avian influenza virus challenge .However, in healthy mice, immunization only once with low dose provided a full protection.