Antigenic characterization
Antigenic analysis of three Egyptian NDVs AR2178-14, R1973-11-cl4 and R1954-11-cl6 as well as of another five reference strains was performed by hemagglutination inhibition (HI) assay, as described (CEC, 1992). In addition to a panel of four polyclonal sera (see previous section) and five HN-specific monoclonal antibodies were used (mAb 617/161, mAb U85, mAb 7D4 were a generous gift from AVLA-Weybridge and mAb 39-2, mAb 10 were a gift from Bernd Köllner, FLI)