1. Antigenic analysis of highly pathogenic avian influenza virus H5N1 sublineages co-circulating in Egypt.
- Author
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Watanabe Y, Ibrahim MS, Ellakany HF, Kawashita N, Daidoji T, Takagi T, Yasunaga T, Nakaya T, and Ikuta K
- Subjects
- Amino Acid Sequence, Animals, Antibodies immunology, Base Sequence, Cell Line, Chick Embryo, Chickens genetics, Chickens immunology, Chickens virology, Cross Reactions genetics, Cross Reactions immunology, Disease Outbreaks, Dogs, Egypt epidemiology, Evolution, Molecular, Glycosylation, HEK293 Cells, Hemagglutinin Glycoproteins, Influenza Virus genetics, Humans, Influenza Vaccines immunology, Influenza in Birds epidemiology, Influenza in Birds genetics, Influenza in Birds immunology, Molecular Sequence Data, Mutation genetics, Mutation immunology, Phylogeny, Prevalence, Antigens, Viral immunology, Hemagglutinin Glycoproteins, Influenza Virus immunology, Influenza A Virus, H5N1 Subtype genetics, Influenza A Virus, H5N1 Subtype immunology, Influenza in Birds virology
- Abstract
Highly pathogenic avian influenza virus H5N1 has spread across Eurasia and Africa, and outbreaks are now endemic in several countries, including Indonesia, Vietnam and Egypt. Continuous circulation of H5N1 virus in Egypt, from a single infected source, has led to significant genetic diversification with phylogenetically separable sublineages, providing an opportunity to study the impact of genetic evolution on viral phenotypic variation. In this study, we analysed the phylogeny of H5 haemagglutinin (HA) genes in influenza viruses isolated in Egypt from 2006 to 2011 and investigated the effect of conserved amino acid mutations in the HA genes in each of the sublineages on their antigenicity. The analysis showed that viruses in at least four sublineages still persisted in poultry in Egypt as of 2011. Using reverse genetics to generate HA-reassortment viruses with specific HA mutations, we found antigenic drift in the HA in two influenza virus sublineages, compared with the other currently co-circulating influenza virus sublineages in Egypt. Moreover, the two sublineages with significant antigenic drift were antigenically distinguishable. Our findings suggested that phylogenetically divergent H5N1 viruses, which were not antigenically cross-reactive, were co-circulating in Egypt, indicating that there was a problem in using a single influenza virus strain as seed virus to produce influenza virus vaccine in Egypt and providing data for designing more efficacious control strategies in H5N1-endemic areas.
- Published
- 2012
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