Rotavirus-neutralizing antibodies inhibit virus binding to integrins α2β1 and α4β1

Rotavirus outer capsid proteins VP5*, VP8* and VP7 elicit neutralizing, protective antibodies. The α2β1 integrin is a cellular receptor for rotavirus that is bound by VP5*. Some rotaviruses also recognize the α4β1 integrin. In this study, the effects of antibodies to rotavirus on virus binding to recombinant α2β1 and α4β1 expressed on K562 cells were determined. All neutralizing monoclonal antibodies to VP5* tested (YO-2C2, 2G4, 1A10) and two to VP7 (RV-3:2, RV-4:2) inhibited rotavirus binding to α2β1. Rotavirus binding to α4β1 was reduced by 2G4 and neutralizing antibody F45:2, directed to VP7. However, a neutralizing antibody to VP8* (RV-5:2) and one to VP7 (RV-3:1) did not affect rotavirus binding to these integrins. Virus-cell binding was unaffected by non-neutralizing antibody RVA to the rotavirus inner capsid protein VP6. The attachment of human rotavirus strain Wa to these integrins was inhibited by infection sera with neutralizing activity collected from two children hospitalised with severe rotavirus gastroenteritis. A negative reference serum did not affect rotavirus-cell attachment. As the binding of rotaviruses to α2β1 and α4β1 is inhibited by neutralizing antibodies to VP5* and VP7, and serum from children with rotavirus disease, rotavirus recognition of these integrins may be important for host infection.