tetano
Editor, Senior Moderator
Clin Vaccine Immunol. 2012 Jul 18. [Epub ahead of print]
Migration of the Swine Influenza Virus δ-Cluster Hemagglutinin N-linked Glycosylation Site from N142 to N144 Results in Loss of Antibody Cross Reactivity.
Hause BM, Stine DL, Sheng Z, Wang Z, Chakravarty S, Simonson RR, Li F.
Source
Newport Laboratories, Worthington, Minnesota.
Abstract
Routine antigenic characterization of swine influenza virus isolates in a high throughput serum neutralization (HTSN) assay found that approximately 20% of isolates were not neutralized by a panel of reference antisera. Genetic analysis revealed that nearly all of the neutralization-resistant isolates possessed a seasonal human-lineage hemagglutinin (δ-cluster). Subsequent sequencing analysis of full length hemagglutinin (HA) identified a conserved N144 present only in neutralization-resistant strains. N144 lies in a predicted N-linked glycosylation consensus sequence N-X-S/T (where X is any amino acid except proline). Interestingly, neutralization-sensitive viruses all had predicted N-linked glycosylation sites at N137 or N142 with threonine (T) occupying position 144 of HA. Consistent with HTSN assay, hemagglutination inhibition (HI) and serum neutralization (SN) assays demonstrated that migration of the potential N-linked glycosylation from N137 or N142 to N144 resulted in a greater than eight-fold decrease in titers. These results were further confirmed in a reverse genetics system where syngenic viruses varying only with predicted N-glycosylation sites at either N142 or N144 exhibited distinct antigenic characteristics as observed in field isolates. Molecular modeling of the hemagglutinin protein containing N142 or N144 in complex with neutralizing antibody suggests that N144-induced potential glycosylation may sterically hinder access of antibody to the hemagglutinin head domain, which allows viruses to escape neutralization. As N-linked glycosylation at these sites have been implicated in genetic and antigenic evolution of human influenza A viruses, we conclude that the relocation of the hemagglutinin N-linked glycosylation site from N142 to N144 render swine influenza virus δ-cluster viruses resistant to antibody-mediated neutralization.
PMID:
22815146
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/22815146
Migration of the Swine Influenza Virus δ-Cluster Hemagglutinin N-linked Glycosylation Site from N142 to N144 Results in Loss of Antibody Cross Reactivity.
Hause BM, Stine DL, Sheng Z, Wang Z, Chakravarty S, Simonson RR, Li F.
Source
Newport Laboratories, Worthington, Minnesota.
Abstract
Routine antigenic characterization of swine influenza virus isolates in a high throughput serum neutralization (HTSN) assay found that approximately 20% of isolates were not neutralized by a panel of reference antisera. Genetic analysis revealed that nearly all of the neutralization-resistant isolates possessed a seasonal human-lineage hemagglutinin (δ-cluster). Subsequent sequencing analysis of full length hemagglutinin (HA) identified a conserved N144 present only in neutralization-resistant strains. N144 lies in a predicted N-linked glycosylation consensus sequence N-X-S/T (where X is any amino acid except proline). Interestingly, neutralization-sensitive viruses all had predicted N-linked glycosylation sites at N137 or N142 with threonine (T) occupying position 144 of HA. Consistent with HTSN assay, hemagglutination inhibition (HI) and serum neutralization (SN) assays demonstrated that migration of the potential N-linked glycosylation from N137 or N142 to N144 resulted in a greater than eight-fold decrease in titers. These results were further confirmed in a reverse genetics system where syngenic viruses varying only with predicted N-glycosylation sites at either N142 or N144 exhibited distinct antigenic characteristics as observed in field isolates. Molecular modeling of the hemagglutinin protein containing N142 or N144 in complex with neutralizing antibody suggests that N144-induced potential glycosylation may sterically hinder access of antibody to the hemagglutinin head domain, which allows viruses to escape neutralization. As N-linked glycosylation at these sites have been implicated in genetic and antigenic evolution of human influenza A viruses, we conclude that the relocation of the hemagglutinin N-linked glycosylation site from N142 to N144 render swine influenza virus δ-cluster viruses resistant to antibody-mediated neutralization.
PMID:
22815146
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/22815146