Figure Legends
Figure 1 Antigenic cartography of EA H1N1 SIVs. Filled squares
and circles represent the positions of antisera and viruses,
respectively. The spacing of one gridline corresponds to an HI
measurement, which equals a 2-fold difference in the HI assay. All the
three axes represent antigenic distance. Strains belonging to the same
antigenic cluster are encircled in a circle. Details of the HI assay
data have been reported previously(Yang et
al., 2016).
Figure 2 (A) Amino acid differences in HA1 protein between
GX/18 and GD/104 viruses are shown as single letters at the indicated
positions. Each amino acid of GX/18 is shown before the number of the
position, and that of GD/104 is shown after the number of the position.
(B) 3D structure of the HA protein with 9 different amino acids. The 3D
structure of GX/18-HA protein is predicted by SWISS-MODEL and analyzed
with PyMOL software. Different amino acids in HA1 protein are marked
with different color. Residues located in antigenic site Sa are labeled
as blue, site Sb as yellow, and site Ca2 as red. *, since the amino acid
at position 175 is buried internally, the effect of E175R mutation on
antigenicity was not evaluated.
Figure 3 The reactivity of rGX/18 viruses bearing different
amino acid mutations in HA with mAb102-95. The reactivity was tested by
using the HI assay and the dashed line indicates the limit of detection.
Figure 4 Structural analysis of amino acid mutation G158E. The
structural change from 158G to 158E is analyzed by use of PyMOL
software, and the figure only shows the difference of R group.
TABLE 1 Primers used for pBD cDNA construction and for
introducing mutations into the HA gene of the reassortant and mutant
viruses.