Study On The Preparation And Application Of Infectious Bronchitis Virus HI Antigen

Avian Infectious Bronchitis(IB) is an acute and highly infectious respiratory disease, caused by the avian infectious bronchitis virus(IBV). Since the first outbreak in USA in the 1930s, IB has become an important disease of poultry around the world. IBV is a single-stranded RNA virus, the gene of the virus always mutated owing to it’s point-mutation and gene recombination and the pressure of immunity, So the serotype of IBV has many categories. Different serotypes have lower or no protection. Currently, IB has often been found in China,even if in those farms where IB vaccine had been vaccinated, the incidence is still widely, Which result in serious economic losses to the poultry industry.In the test,various conditions that can effect the preparing and storing IBV HI antigen have been researched,the best conditions have been groped and having established hemagglutination test and hemagglutination inhibition test of IBV. The cost of the HI antigen is very cheap,this is the foundation that IBV HI is utilized in the production.In the test,10-day-old specific pathogen free embryos were inoculated via the allantoic cavity with 0.1 mL of a low embryonic passage of the virus (107 to108 EID50/mL).Allantoic fluid was harvested from chilled viable embryos and clarified by centrifugation at 4,000 g for 40 minutes,the pellet was discarded,and virus was concentrated from the supernerantand fluid by centrifugation at 30,000g for 3 hours. The virus pellets was resuspended to 1/100 the original AAF volume in Tris-Hcl-buffer saline, then mixed with R.W.F.C10, the ratio of volume of buffer containing pellets and R.W.F.C10 is 10/4.The mixture was agitated occasionally during incubation.All IBV strains tested demonstrated positive HA activity with chicken red blood cells.The antigen was stored in liquid state at 4℃.The serological survey for avian infectious bronchitis virus in commercial and backyard village chickens in Henan province using hemagglutination inhibition (HI)test was carried out.All the breeding poultry and most of the commeicial chickens were positive for antibodies to IBV.But the seroprevalence in backyard is low.The implications of the survey is that IBV M41 HI antigen prepared by our method can be used in production.