Fig. 5.

Pairwise analysis of inter- and intravariant differences indicated that a minimum of 18-amino acid changes in the VP1 sequence are required for significant antigenic differences. (A) Scatterplot analysis that compares the antigenic distance and amino acid differences on the full VP1 sequences for representative GII.4 VLP pairs. Antigenic distance and amino acid difference data were derived from Figs. 3B and 4B, respectively. Virus (represented by VLPs) pairs are color coded to show intervariant (red) and intravariant (blue) pairs. The vertical dotted line indicates the amino acid difference = 18, while the horizontal dotted line indicates where antigenic distance = 4. (B) Statistical analyses of antigenic distances between intra- and intervariant pairings. P < 0.01 in unpaired t test. (C) Statistical analyses of antigenic distances between VLP pairs at <18 or ≥18 amino acid differences, respectively. P < 0.01 in unpaired t test.