Screening Of Monoclonal Antibodies Of Different Tissue Tropism Avian IBV Strains

Infectious bronchitis (IB) is an acute and highly contagious disease by avian infectiousbronchitis virus (IBV).IBV exists as dozens of serotypes,the frequency of variation is high,and the tissue tropism of IBV is also change constantly. At present, The breathing type, kidneytype, egg-drop type,glandular stomach type and intestinal type were recognized by theinternationality. In recent years, the research about the tissue tropism of IBV was reported athome and abroad, but the conclusions are different. This study attempts to compare thedifferences of S1protein of different pathogenic strains of respiratory type and kidney type,and to find a monoclonal antibody which has specific neutralizing activity, in order toinvestigate the difference of the pathogenicity and tissue tropism of different IBV strains.BALB/c mice were immunized with the concentrated IBV H120virus and K136virus.The hybridoma technique was used, and the indirect ELISA detection method was established.By screening and cloning, three strains of hybridoma cell lines secreting monoclonalantibody(McAbs) were obtained, and named3F6G7,1E9A3and4F5E8, which against IBVH120and K136. The McAbs3F6G7was IgG2b subtype with Kappa chain, and the other twowere IgM subtype. The results of ELISA showed that the McAbs3F6G7reacted strongly withH120comparing with K136, but1E9A3and4F5E8showed not the difference. The threeMcAbs could react with other IBV strains, indicating the conservative epitopes and groupspecificity. The results of Western blot showed that the three McAbs reacted with S1proteinof IBV specifically. The neutralizing activity of three McAbs was showed in the results ofvirus neutralization test, this further confirmed that that the three were against S1protein, but3F6G7did not show the difference in the ELISA test.Although this study failed to screen out the discriminating monoclonal antibody, but canprovids reference for the further study about tissue tropism of IBV. In addition, the threestrains of McAbs can be obtained as a candidate tool for the prevention, detection anddiagnosis of IBV and effective materials for the research of epitope of S1protein.It also hasthe value of research and practice.