Binding specificity of P[8] VP8* proteins of rotavirus vaccine strains with histo-blood group antigens

RotaTeq® and Rotarix™ are two common human rotavirus (RV) vaccines currently on the market worldwide. Recent studies indicate histo-blood group antigens (HBGAs) may be attachment factors for RVs. The P[8] VP8* proteins of RotaTeq and Rotarix were expressed and purified, and their binding specificities were evaluated. Saliva-based binding assays showed that the VP8* proteins bound to the saliva samples of secretors irrespective of ABO blood types. However, in the oligosaccharide binding assay, the VP8* proteins displayed no specific binding to the HBGAs tested, including Lewis b and H1. The structure of RotaTeq P[8] VP8* was solved at 1.9 Å. Structural comparisons revealed that the putative receptor binding site was different to that of other genotypes and displayed a novel potential binding region. These findings indicate RotaTeq and Rotarix may have better efficiency in areas with a high percentage of secretors.