Glycosylation at 11Asn on hemagglutinin of H5N1 influenza virus contributes to its biological characteristics

In this study, site-directed mutagenesis was used to generate single or double mutant rSY- Δ10(10NNAT), rSY-Δ11(10NNSA), and rSY-Δ10/11(10NNAA) of the overlapping glycosylation site (10NNST) on the HA of A/Mallard/Huadong/S/2005(SY). By using Western blot analysis, we show that both rSY-Δ11 and rSY-Δ10/11 mutant viruses had significant delay on HA cleavage and a reduced HA molecular mass compared to the wild-type virus rSY, while the rSY-Δ10 mutant virus exhibited a similar HA molecular mass to that of the wild-type virus rSY. Interestingly, both rSY-Δ11 and rSY-Δ10/11 mutant viruses reverted their glycosylation sites at 11N after passage, indicating that 11N is a true and c ritical glycosylation site. Compared to the wild-type virus rSY, rSY-Δ11 and rSY-Δ10/11 mutant viruses had decreased growth rates, reduced thermo- and pH-stability, decreased pathogenicity, and limited systemic spread. Therefore, our study suggests that the 11N glycosylation site plays a key role in HA cleavage, structural stability and pathogenicity in H5 subtype avian influenza virus.
Source: Veterinary Research - Category: Veterinary Research Source Type: research