Purification of an outer capsid glycoprotein of neonatal calf diarrhea virus and preparation of its antisera.

An outer capsid glycoprotein, VP 7, was purified from a bovine rotavirus, neonatal calf diarrhea virus, by isoelectric focusing in glycerol gradients after disruption of the outer capsid. Its isoelectric point was found to be about 4.5. Guinea pigs were immunized with this VP 7 preparation. The antisera possessed both neutralizing and hemagglutination-inhibiting activities as well as complement-fixing activity, suggesting that VP 7 is a protein involved in hemagglutination and initiation of infection. When these antisera were reacted with a simian rotavirus, their antibody titers were low by hemagglutination-inhibiting and complement-fixing assays, but one serum neutralized the simian rotavirus as efficiently as it did homologous neonatal calf diarrhea virus.