title: Identification of a variable epitope on the Newcastle disease virus hemagglutinin-neuraminidase protein.
abstract: Fifteen virulent Newcastle disease viruses (NDVs) were isolated from diseased birds in Eastern China in 2005. To investigate the antigenic variation in the epitopes on NDV hemagglutinin-neuraminidase (HN) protein, these isolates, together with six reference strains, were subjected to the hemagglutination inhibition (HI) tests using five HI-positive monoclonal antibodies (MAbs) against velogenic NDV strain ZJ1. The MAbs 2G5, 3A4, 3B5 and 6B1 recognized 12 of the 15 NDV isolates, and exhibited HI activity towards the six reference strains. However, these MAbs did not react with three local isolates, JS-02/05, JS-06/05 and JS-10/05. HN gene sequence analysis of all NDV strains revealed that these MAb-resistant NDV isolates possessed residue K at position 347 of the HN protein, whereas all remaining strains possessed E or G at the same site. To determine the contribution of the residue at position 347 to antigenic epitope formation, we generated by reverse genetics two recombinant viruses, ZJ1HNK with an E347K mutation on ZJ1 HN, and JSHNE with a K347E mutation on JS-06/05 HN. The HI test demonstrated that ZJ1HNK lost reactivity with MAbs 2G5, 3A4, 3B5 and 6B1, whereas JSHNE did react with these MAbs. Further verification by immunofluorescent assay demonstrated that residue 347 was a critical determinant for formation of the antigenic epitope (residues 345-353) on the HN protein.
authors.affiliation: Animal Infectious Disease Laboratory, School of Veterinary Medicine, Yangzhou University, 48 East Wenhui Road, Yangzhou 225009, China.
authors.forename: Shunlin
authors.initials: S
authors.lastname: Hu
authors.forename: Tongyan
authors.initials: T
authors.lastname: Wang
authors.forename: Yuliang
authors.initials: Y
authors.lastname: Liu
authors.forename: Chun
authors.initials: C
authors.lastname: Meng
authors.forename: Xiaoquan
authors.initials: X
authors.lastname: Wang
authors.forename: Yantao
authors.initials: Y
authors.lastname: Wu
authors.forename: Xiufan
authors.initials: X
authors.lastname: Liu
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000914:Antibodies, Viral / Q000276:immunology; D000940:Antigenic Variation / Q000235:genetics; D002478:Cells, Cultured; D002645:Chickens; D002681:China; D003429:Cross Reactions / Q000235:genetics / Q000276:immunology; D000939:Epitopes / Q000235:genetics / Q000276:immunology; D005777:Geese; D015707:HN Protein / Q000235:genetics / Q000276:immunology; D008969:Molecular Sequence Data; D009154:Mutation; D009521:Newcastle Disease / Q000276:immunology / Q000821:virology*; D009522:Newcastle disease virus / Q000201:enzymology* / Q000235:genetics* / Q000276:immunology; D011201:Poultry Diseases / Q000276:immunology / Q000821:virology; D017421:Sequence Analysis
chemical_list: D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D000939:Epitopes; D015707:HN Protein