title: Amino acid mutations in the env gp90 protein that modify N-linked glycosylation of the Chinese EIAV vaccine strain enhance resistance to neutralizing antibodies.
abstract: The Chinese EIAV vaccine is an attenuated live virus vaccine obtained by serial passage of a virulent horse isolate (EIAVL) in donkeys (EIAVD) and, subsequently, in donkey cells in vitro. In this study, we compare the env gene of the original horse virulent virus (EIAVL) with attenuated strains serially passaged in donkey MDM (EIAVDLV) and donkey dermal cells (EIAVFDDV). Genetic comparisons among parental and attenuated strains found that vaccine strains contained amino acid substitutions/deletions in gp90 that resulted in a loss of three potential N-linked glycosylation sites, designated g5, g9, and g10. To investigate the biological significance of these changes, reverse-mutated viruses were constructed in the backbone of the EIAVFDDVinfectious molecular clone (pLGFD3). The resulting virus stocks were characterized for replication efficiency in donkey dermal cells and donkey MDM, and were tested for sensitivity to neutralization using sera from two ponies experimentally infected with EIAVFDDV. Results clearly show that these mutations generated by site-directed mutagenesis resulted in cloned viruses with enhanced resistance to serum neutralizing antibodies that were also able to recognize parental viruses. This study indicates that these mutations played an important role in the attenuation of the EIAV vaccine strains.
authors: College of Food Science, Northeast Agricultural University, Harbin, 150030, China.
authors: Xiue
authors: X
authors: Han
authors: College of Food Science, Northeast Agricultural University, Harbin, 150030, China.
authors: Ping
authors: P
authors: Zhang
authors: College of Food Science, Northeast Agricultural University, Harbin, 150030, China.
authors: Wei
authors: W
authors: Yu
authors: National Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150030, China.
authors: Wenhua
authors: W
authors: Xiang
authors: College of Food Science, Northeast Agricultural University, Harbin, 150030, China. hrblxd1@126.com.
authors: Xiaodong
authors: X
authors: Li
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D057134:Antibodies, Neutralizing / Q000276:immunology; D000914:Antibodies, Viral / Q000276:immunology; D002460:Cell Line; D002478:Cells, Cultured; D015686:Gene Products, env / Q000737:chemistry / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D016679:Genome, Viral; D006031:Glycosylation; D006736:Horses; D004860:Infectious Anemia Virus, Equine / Q000235:genetics* / Q000276:immunology*; D009154:Mutation; D009500:Neutralization Tests; D014765:Viral Vaccines / Q000235:genetics* / Q000276:immunology*
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D015686:Gene Products, env; D014765:Viral Vaccines
keywords: Glycosylation; Gp90 variation; Neutralization resistance