Research On The Purification、Screening And Vaccine Production Technology Of AIV Re-4Strain

Avian Influenza (AI), also named True Fowl Plague, Europe Fowl Plague, is a virulent infection caused by Influenza A virus. Since the spread of the disease, huge economic losses has been brought to the poultry industry all over the world, and it has grown to one of the most important diseases threatening poultry industry, which became an A-list disease of OIE and WTO. Avian Influenza virus is a member of Influenza A virus genus, which is a subfamily of Orthomyxoviridae. The genome is composed of8single-stranded, nonsegmented, negative-sense RNA viruses, coding10proteins(HA, NA, NP, M1, M2, PB1, PB2, PA, NS1, and NS2). The nucleocapsid have the similar antigenicity with the nuclear matrix proteins, but can be divided into16subtype H (HI-H16) and10subtype N (H1～H10). The incidence rate is very high once it outbreak. Vaccine inoculation is the principal mean to prevent outbreaks and spread of the disease both in and aboard.In this experiment, plaque purification technology and SPF end-point dilution method were used to purify the RE-4vaccine strain. Plagues formed early, independent, and more were chosen. After being purified for4generations, chicken embryo end-point dilution was applied. Allantoic fluid with the highest dilution rate and hemagglutiantion titer was chosen for further end-point dilution. After being purified for4generations, the stability of the purified strain was improved. Compared with the original strain, the hemagglutination titer the purified strain was101og2compared to 91og2of the original virus, the EID50was10-8.5/0.1mL compared to107.9/0.1mL of the original virus,and the stability of the purified strain were good. Allantoic fluid with the highest dilution rate and hemagglutiantion titer was chosen for further end-point dilution. Inactivated oil emulsion vaccine was made from the vaccine strain and the following immunogenicity test, safety test and the test of immunogenic efficacy indicated that the purified strains were safe, with better immunogenicity and effectiveness which posed no adverse effects to the chickens, fit the Requirements of "State Veterinary Biological Products criterion"...