Submitted to: Journal of Food Protection
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/17/2007
Publication Date: 10/1/2007
Citation: Tian, P., Engelbrektson, A.L., Jiang, X., Zhong, W., Mandrell, R.E. 2007. Norovirus recognizes histo-blood group antigens on the gastrointestinal cells of clams, mussels and oysters: a possible mechanism of bio-accumulation. Journal of Food Protection. 70(9):2140-2147. Interpretive Summary: Outbreaks of norovirus (NOR) gastroenteritis are often associated with the consumption of contaminated bivalves, such as oysters, clams and mussels. The mechanism of viral accumulation in bivalves could include mechanical entrapment, chemical, Van der Waal, or ionic bonding, and/or interactions between viruses and specific ligands. Histo-blood group antigens (HBGA) on human gastrointestinal (GI) cells have been shown previously to be receptors for NOR, and type A-like HBGA in Virginica oysters co-localize with the location of binding of genotype I (GGI) recombinant Norwalk viral like particles (rNVLP). It is not known, however, if other bivalves also have HBGA and can bind other strains of NOR, in particular genotype II (GGII) NOR. We found that all three oyster species expressed type A-like and type O-like HBGA in their GI tissue as measured by ELISA. All mussels and clams also expressed type A-like HBGA, and some contained also type-O-like HBGA. Additionally, recombinant norovirus viral like particles (rNOR) bound to ELISA wells coated with oyster, mussel or clam GI homogenates. This binding was inhibited by rNORs pre-incubated with the corresponding HBGA-specific MAbs or with samples of human saliva from type A or type O individuals. Co-localization of rNORs and HBGA on GI epithelial cells of oysters, mussels, and clams was observed by immunofluorescent histochemical staining under two-channel confocal scanning laser microscopy. Also, the binding of rNOR to HBGA on homogenates of oyster GI tissue was inhibited by HBGA in washing solutions. This is the first report of the presence of multiple HBGA in oyster, mussel and clam GI tissues and their role in specific binding of rNOR to HBGA of bivalves. These results indicate that human NORs concentrate in the GI cells of bivalves by specific binding to HBGA, rather than by a non-specific entrapment within the tissues. The results also indicate that the binding of rNOR, and potentially intact NOR, could be reversed by a depuration process including HBGA like compounds in the washing procedure.
Technical Abstract: In this study, a set of HBGA-specific monoclonal antibodies (MAbs) was used to detect the expression of HBGA in three oyster species consumed commonly (pacific, virginica, and kumamato), and manila clams, and blue mussels. rNVLPs were applied to plate coated with oyster, mussel or clam GI homogenates, and measured by ELISA assay using polyclonal antibodies against NV. Co-localization of HBGA and rNVLP binding on epithelial cells of bivalve gastro-intestine tissue were determined by immuno-staining and analyzed in three-channel confocal microscopy.