The Role of Influenza A Virus Hemagglutinin Residues 226 and 228 in Receptor Specificity and Host Range Restriction

Abstract

Influenza A viruses can be isolated from a variety of animals, but their range of hosts is restricted. For example, human influenza viruses do not replicate in duck intestine, the major replication site of avian viruses in ducks. Although amino acids at positions 226 and 228 of hemagglutinin (HA) of the H3 subtype are known to be important for this host range restriction, the contributions of specific amino acids at these positions to restriction were not known. Here, we address this issue by generating HAs with site-specific mutations of a human virus that contain different amino acid residues at these positions. We also let ducks select replication-competent viruses from a replication-incompetent virus containing a human virus HA by inoculating animals with 1010.5 50% egg infectious dose of the latter virus and identified a mutation in the HA. Our results showed that the Ser-to-Gly mutation at position 228, in addition to the Leu-to-Gln mutation at position 226 of the HA of the H3 subtype, is critical for human virus HA to support virus replication in duck intestine.

The Murine Coronavirus Hemagglutinin-esterase Receptor-binding Site: A Major Shift in Ligand Specificity through Modest Changes in Architecture

“…Viruses have evolved to selectively use particular Sia variants and their attachment proteins are high-specificity sialolectins, the binding of which might depend on the identity of the penultimate residue in the sugar chain, the type of glycosidic linkage and/or the presence or absence of substitutions [5][6][7][8][9]. Ultimately, this preference in Sia receptor usage affects host-, organ-, and cell-tropism [10][11][12][13][14], the course and outcome of infection [15][16][17][18] as well as the efficacy of intra-and cross-species transmission [14,19], all to extents not yet fully appreciated.…”

Avian Influenza Virus Glycoproteins Restrict Virus Replication and Spread through Human Airway Epithelium at Temperatures of the Proximal Airways

“…To test whether HA and/or NA contributed to the restricted phenotype of avian influenza viruses at 32uC, we used reverse genetics to generate mutant viruses genetically altered to confer avian virus-like glycoprotein specificities on the A/Victoria/3/75 background. First, mutations in HA previously shown to switch sialic acid usage from a2,6 to a2,3 linkages (L226Q, S228G) [40] were introduced to generate the Vic-226-228HA virus. Second, we generated a reassortant virus in which the Victoria NA was replaced by that of the avian virus A/ Chick/Italy/1347/99 to generate Vic+Chick N1.…”

“…Recombinant viruses, including wild-type A/Victoria/3/75 (H3N2) and mutants in either the A/Victoria/3/75 (H3N2) or A/PR/8/24 (H1N1) background, were generated from cloned cDNA in 293T and MDCK cell co-cultures as previously described [52,53]. Mutant viruses were generated in either the A/Victoria/3/75 (H3N2) or A/PR/8/34 (H1N1) genetic background as follows: 1) Vic 627PB2; A/Victoria/3/75 containing a lysine to glutamic acid amino acid substitution at position 627; 2) Vic-226-228HA; A/ Victoria/3/75 containing two amino acid substitutions in the HA gene (L226Q, S228G) that confer an avian-like receptor binding preference [6,40]; 3) Vic+Chick N1; A/Victoria/3/75 in which segment 6 containing the endogenous N2 NA gene was exchanged for the N1 NA gene from avian isolate A/Chick/Italy/1347/99; 4) Vic-226-228HA+Chick N1; A/Victoria/3/75 containing both L226Q and S228G mutations and the avian N1; 5) PR8+Vic HA/ NA; A/PR/8/34 in which the endogenous H1 and N1 were replaced with the H3 and N2 from A/Victoria/3/75 and 6) PR8+Chick HA/NA (RD3); A/PR/8/34 in which the endogenous H1 and N1 were replaced with the H7 and N1 from A/ Chick/Italy/1347/99. (RD3 was previously described as a candidate vaccine strain [41].)…”

Host range, host specificity and hypothesized host shift events among viruses of lower vertebrates

“…Influenza haemagglutinin binds to sialic acid linked to galactose on the surface of the targeted cell, and the differing nature of the sialic acid-galactose linkages in birds and humans provides an important barrier to host shift events. In this sense, a number of amino acid substitutions have been produced in influenza haemagglutinin to adjust to the different receptors [10][11][12][13][14]. Neuraminidase, the protein responsible for cleaving the haemagglutinin from the receptor surface, also seems to be adapted to the particular sialic acid linkages [15].…”