title: [Influence of antibody-mediated immune pressure on neuraminidase gene mutations of avian influenza virus H9N2].
abstract: LG1 strain of avian influenza virus H9N2 was passaged continuously for 40 generations in chicken embryos with anti-LG1 maternal antibodies in 4 parallel experiments, of which 3 experiments had a stable mutation of "G" to "A" at #99 of the neuraminidase gene(NA)from the 20th passage resulting in a change of Met to Ile and 2 had a stable mutation of "A" to "G" at #473 of the NA gene from the 30th passage resulting in a change of Asn to Ser which occurred in the 50th passage of another experiment. Eighty continuous passages in chicken embryos without antibody did not have the same mutation, indicating that the mutations of the 2 positions were associated with selective pressure of antibodies. Analysis of the ratios of nonsynonium (NS) vs synonium (S) mutations of nucleic acids demonstrated that NS/S of 4 parallel experiments with antibodies was 4.6 (32/7) compared with 2.0 (16/8) of the 2 experiments without antibodies and this significant difference implied the selective pressure of antibodies.
authors.affiliation: College of Animal Science and Technology, Shandong Agricultural University, Key Laboratory of Animal Biotechnology and Disease Control and Prevention of Shandong Province, Tai'an 271018, China. duyan11290719@163.com
authors.forename: Yan
authors.initials: Y
authors.lastname: Du
authors.forename: Ben-Hong
authors.initials: BH
authors.lastname: Lou
authors.forename: Zhuan-Chang
authors.initials: ZC
authors.lastname: Wu
authors.forename: Peng
authors.initials: P
authors.lastname: Zhao
authors.forename: Zhi-Zhong
authors.initials: ZZ
authors.lastname: Cui
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology*; D002642:Chick Embryo; D053127:Influenza A Virus, H9N2 Subtype / Q000235:genetics* / Q000276:immunology; D009154:Mutation; D009439:Neuraminidase / Q000235:genetics*
chemical_list: D000914:Antibodies, Viral; D009439:Neuraminidase