Histo-blood group antigens in Crassostrea gigas and binding profiles with GII.4 Norovirus

Noroviruses (NoVs) are the main cause of viral gastroenteritis outbreaks worldwide, and oysters are the most common carriers of NoV contamination and transmission. NoVs bind specifically to oyster tissues through histo-blood group antigens (HBGAs), and this facilitates virus accumulation and increases virus persistence in oysters. To investigate the interaction of HBGAs in Pacific oysters with GII.4 NoV, we examined HBGAs with ELISAs and investigated binding patterns with oligosaccharide-binding assays using P particles as a model of five GII.4 NoV capsids. The HBGAs in the gut and gills exhibited polymorphisms. In the gut, type A was detected (100%), whereas type Leb (91.67%) and type A (61.11%) were both observed in the gills. Moreover, we found that seasonal NoV gastroenteritis outbreaks were not significantly associated with the specific HBGAs detected in the oyster gut and gills. In the gut, we found that strain-2006b and strain-96/96US bound to type A and H1 but only weakly bound to type Leb; in contrast, the Camberwell and Hunter strains exhibited weak binding to types H1 and Ley, and strain-Sakai exhibited no binding to any HBGA type. In the gills, strain-96/96US and strain-2006b bound to type Leb but only weakly bound to type H1; strains Camberwell, Hunter, and Sakai did not bind to oyster HBGAs. Assays for oligosaccharide binding to GII.4 NoV P particles showed that strain-95/96US and strain-2006b strongly bound to type A, B, H1, Leb, and Ley oligosaccharides, while strains Camberwell and Hunter showed weak binding ability to type H1 and Ley oligosaccharides and strain-Sakai showed weak binding ability to type Leb and Ley oligosaccharides. Our study presents new information and enhances understanding about the mechanism for NoV accumulation in oysters. Further studies of multiple NoV-tissue interactions might assist in identifying new or improved strategies for minimizing contamination, including HBGA-based attachment inhibition or depuration.