Antigenic and Glycan-Binding Characteristics of Norovirus GII.20 Capsid
Protein VP1
Abstract
Norovirus (NoV) is the major pathogen causing acute gastroenteritis
globally. The capsid protein VP1 of GII.20 NoV is closely related to
that of the prevalent GII.4 genotype. In this study, we explored the
antigenic and glycan binding characteristics of GII.20 VP1. GII.20 VP1
was obtained and presented virus-like particles (VLPs) with a diameter
of approximately 38 nm. Polyclonal sera against GII.20 VLPs showed good
binding activity even at a dilution of 1:819200 and presented certain
binding to GII.4 VLP. In addition, polyclonal sera against GII.4 VLPs
showed binding to GII.20 VLP. Polyclonal sera exhibited neutralization
effects on GII.20 and GII.4 VLPs in the blocking assay. Furthermore,
GII.20 VLP bound to A/B/O type saliva. Sequence analyses revealed that
the amino acids in the presumed glycan binding region of GII.20 was
similar to that of GII.4. The structure model of the GII.20 P protein
showed the greatest structural similarity with those of GII.17 and GII.4
P proteins. In summary, GII.20 VP1 exhibited cross-antigenicity and
similar saliva-binding characteristics to that of the prevalent GII.4,
which may help explain the low prevalence of GII.20. Considering the
high impact of GII.4 NoVs, further surveillance is necessary to monitor
the evolution and variation of GII.20 NoV.