Characterization of the G serotype and genogroup of New Delhi newborn rotavirus strain 116E.

We recently reported that the culture-adapted neonatal rotavirus strain 116E represented the first P type 11 human rotavirus, based on the close relationship of its VP4 protein to that of the bovine serotype G10P11 strain B223. In this study, we demonstrated by sequence analysis and cross-neutralization studies that the VP7 protein of 116E is closely related to those of the human serotype G9 strains, F45 and WI61, but distinct from B223 and other rotaviruses. Low-level cross-neutralization was also observed between strains 116E and B223, probably because of the antigenic similarity of their VP4 proteins. We have demonstrated by RNA-RNA hybridization that strain 116E is a reassortant between strains from the Wa and bovine (KK3-like) genogroups, deriving at least seven genes from the former and at least one gene from the latter. Together with the recent identification of serotype G10P11 newborn rotavirus strains in Bangalore, India (M. Das et al., Virology, 194, 374-379, 1993), these results are consistent with the hypothesis that reassortment may be an important mechanism for generation of rotavirus strains of newborns.