HA: haemagglutinin; Met: methionine; +/- indicates whether the residue is
associated with the gain (+) or loss (−) of a potential
glycosylation site.
a S45N creates a potential glycosylation site
(SSS to
NSS), with
glycosylation occurring at N45.
b S124N removes a potential glycosylation site
(NES to
NEN), with
glycosylation occurring at N122 (antigenic site A).
c T128N and T128A remove a potential glycosylation site
(NWT to
NWN or
NWA), with
glycosylation occurring at N126 (antigenic site A).
d N144D removes a potential glycosylation site
(NSS to
DSS), with
glycosylation occurring at N144 (antigenic site A).
All residue changes that exist in HA among the study samples (yellow), vaccine
strains (purple), and clade consensus sequences (white) are provided. All
sequences that match the A/Perth/16/2009 strain (clade 1) are coloured in pink,
while residues that differ from that strain are shown in blue (first residue
difference) or green (second residue difference). Residues associated with the
gain (+) or loss (−) of a potential glycosylation site are
indicated. Antigenic site assignments are derived from several sources
[60-63]. P0 indicates the original clinical swab
specimen, while P2 indicates the second-passage viral stock grown in MDCK
cells.