The index influenza A virus subtype H5N1 isolated from a human in 1997 differs in its receptor-binding properties from a virulent avian influenza virus.
Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Corporation, Saitama 332-0012, Japan.
Division of Virology, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan.
Laboratory of Veterinary Microbiology, Division of Veterinary Science, Graduate School of Agriculture and Biological Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531, Japan.
Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706, USA.
To gain insight into the events that occur when avian influenza viruses are transmitted to humans, the receptor-binding properties of the index H5N1 influenza virus isolated from a human in 1997 and the A/turkey/Ontario/7732/66 (H5N9) virus were compared, by using a haemadsorption assay. Cells expressing the haemagglutinin (HA) of the human isolate were adsorbed by both chicken red blood cells (RBCs) and human RBCs; those expressing the avian virus HA were only adsorbed by chicken RBCs. These results indicate that human and avian influenza virus H5 HAs differ in their recognition of sialyloligosaccharides on the RBCs of different animal species. Mutational analyses indicated that differences in both the oligosaccharide chains and in the amino acid sequences around the HA receptor-binding site were responsible for this difference in receptor binding. These data further support the concept that alteration in receptor recognition is important for replication of avian viruses in humans.
Influenza A Virus, H5N1 SubtypeAnimalsChickensHemagglutinins, ViralHumansIn Vitro TechniquesInfluenza A virusModels, MolecularMutagenesis, Site-DirectedProtein ConformationReceptors, VirusVirulenceVirus Replication
Structured evidence records
Evidence records
4 total
Receptor Usage2 records
Receptor UsageExtraction confidence 1.00
Key finding
The human H5N1 hemagglutinin binds both human and chicken red blood cells, while the avian H5 hemagglutinin binds only chicken cells, indicating differing recognition of sialyloligosaccharide receptors.
Cells expressing the haemagglutinin (HA) of the human isolate were adsorbed by both chicken red blood cells (RBCs) and human RBCs; those expressing the avian virus HA were only adsorbed by chicken RBCs. These results indicate that human and avian influenza virus H5 HAs differ in their recognition of sialyloligosaccharides on the RBCs of different animal species.
Method
haemadsorption assay; mutational analysis
Receptors
sialyloligosaccharides
Receptor UsageExtraction confidence 1.00
Key finding
Amino acid and glycan differences around the hemagglutinin receptor-binding site determine the variation in receptor recognition between human and avian H5 viruses.
Mutational analyses indicated that differences in both the oligosaccharide chains and in the amino acid sequences around the HA receptor-binding site were responsible for this difference in receptor binding.
Method
mutational analysis
Receptors
HA receptor-binding site
Molecular Adaptation1 records
Molecular AdaptationExtraction confidence 0.95
Key finding
A human H5N1 isolate from 1997 acquired amino acid changes in its HA receptor-binding site that altered sialyloligosaccharide recognition, enabling binding to both avian and human red blood cells.
Cells expressing the haemagglutinin (HA) of the human isolate were adsorbed by both chicken red blood cells and human red blood cells; those expressing the avian virus HA were only adsorbed by chicken red blood cells. Mutational analyses indicated that differences in amino acid sequences around the HA receptor-binding site were responsible for this difference in receptor binding.
The index influenza A virus subtype H5N1 isolated from a human in 1997 differs in its receptor-binding properties from a virulent avian influenza virus.
