Ornpreya SuptawiwatChompunuch BoonarkartWarunya ChakritbudsabongMongkol UiprasertkulPilaipan PuthavathanaWitthawat WiriyaratPrasert AuewarakulMahidol University2018-11-092018-11-092014-01-01Archives of Virology. Vol.160, No.2 (2014), 409-415030486082-s2.0-84925486400https://repository.li.mahidol.ac.th/handle/20.500.14594/34006© 2014, Springer-Verlag Wien. N-linked glycosylation of the influenza virus hemagglutinin (HA) protein plays crucial roles in HA structure and function, evasion of neutralizing antibodies, and susceptibility to innate soluble antiviral factors. The N-linked glycosylation site at position 158 of highly pathogenic H5N1 virus was previously shown to affect viral receptor-binding preference. H5N1 viruses show heterogeneity with respect to the presence of this glycosylation site. Clade 1 viruses that caused outbreaks in Southeast Asia in 2004 contained this glycosylation site, while the site is absent in the more recent clade 2 viruses. Here, we show that elimination of this glycosylation site increases viral virulence in mice. The mutant lacking the glycosylation site at position 158 showed unaltered growth kinetics in vitro and a comparable level of sensitivity to a major antiviral protein found in respiratory secretions, surfactant protein D (SP-D).Mahidol UniversityImmunology and MicrobiologyArticleSCOPUS10.1007/s00705-014-2306-x