An Analysis On The Diversity Of Antigencity Among Infectious Bursal Disease Virus Strains With Monoclonal Antibody And Its Application

By using hybridoma technique, 144 monoclonal antibodies (McAbs) against infectious bursa disease virus (IBDV) were obtained. Which recognized different antigenic epitopes were determined and selected from them, and 27 McAbs by synergistic ELISA. Western blot analysis indicated that all these McAbs reacted with the same vim peptide VP2.1.Indirect fluorescence antibody (IFA) test with the above McAbs wasconducted to analyse the antigenic relationships of different isolates.2.The results demonstrated that all the tested IBDV strains of differentorigins could be divided into two groups of B and C by using the M57, 1.122and M110. The group B included all the virulent strains and they could furtherfell into 6 subgroups by other with different epitope specificities. Amongthe subgroups, the topological distributions of epitopes recognized by McAbswere quite different from each other. The group C included all the tested mid-or mild-virulent vaccine strains, also it could further divided into 5subgroups with some other McAbs.3.The experiment also indicated that 9 of 27 McAbs were reactive with commonepitopes that shared by all members of sero~type 1 IBDV. Among them, McAbsM110 strain showed the strongest reaction in IFA. In contrast, the McAbs M57strain was specific to virulent strains and the L122 strain was specific toattenuated vaccine strains. The virulent strains could lose its antigenicdeterminant recognized by McAbs M57 strain during the passage in CEF andvaccine strains addapted to chick embryos would lose the epitopes reacted withMcAbs L122.4.A reverse passive hemagglutination test (RPIIA) and reverse passivehemagghtination inhibition test (RPHI) procedure for detecting IBDV antigenand anti-IBDV monoclonal antibodies IB1 was developed by suing sheep red bloodcells (SRBC) which were fixed by methylglyoxaland formaldehyde and linked withneutralizing McAbs IBI against type I of IBDV.5.The sensitivity of RPHA was 256 times than that of agar gel precipitation(AGP) and similar to that of sandwich ELISA.6. The sensitivity of RPHI was 256 times than that of agargel precipitation (AGP) , similar to that of sandwich inhibition ELISA. The coefficient of correlation between RPHI and neutralization in chicken embryo fibroblast cell culture was 0.9808.7. When the RPHI was used for titration of maternal antibodies, the passive immunity titers was 3.65, passive immunity liters was 1.46.8. It was found that the antibody level was the highest at the third day after hatching, then dropped gradually and reached the critical level in the 19th-21th day, and the antibodies disappeared in about the 25th day.9. Using RPHI as detection means, i t was found that no matter where the chicken were inoculated vaccine, there were different IBD antibodies in chichens, the differences were remarkable among different chicken farms. The serum antibody of chicks which had clinical syndrome of IBD were lower the normal immunity level. The chicks that were inoculate inactivated IBD vaccine in age of one week could protect effectively. The chickn that free rose had that phenomena antibody to go up by a wide margin in later stage.10. The young chicken's IBD immunity procedure could be made by using the RPHI to examine antibody level, and remarkably reduces the IBD clinical disease incidence rate.