VP4 protein of porcine rotavirus strain OSU expressed by a baculovirus recombinant induces neutralizing antibodies.

The complete VP4 gene of porcine rotavirus strain OSU has been inserted into a baculovirus expression vector under the control of the polyhedrin promoter. The VP4 outer capsid protein, which is a major neutralization antigen in rotavirus, was expressed in high yield in Spodoptera frugiperda cells. Reactivity with polyclonal and monoclonal antibodies suggested that neutralizing epitopes were functionally unaltered on the expressed VP4. The VP4 produced in this system also induced antibodies in guinea pigs which inhibited hemagglutination of OSU and neutralized its infectivity to high titer. The available evidence suggests that the VP4 expressed in insect cells maintained its antigenic configuration and may prove useful in elucidation of (1) the extent of VP4 polymorphism among human and animal rotaviruses and (2) the distribution of VP4 among these viruses.