Identification of a neutralizing epitope on an 82-kDa protein encoded by gene 3 of group C rotavirus

A neutralizing monoclonal antibody (1A5) with hemagglutination inhibition activity was produced against a cultivable porcine group C rotavirus strain (strain AmC-1) and used to identify and map the functional topography of the protein involved in viral neutralization. The 1A5 mAb recognized an 82-kDa protein from infected cells as well as an equivalent in vitro-translated protein programmed with gene 3 of the AmC-1 strain. By employing a method called DNA amplification-restricted transcription-translation a series of C-terminal-truncated fragments of the 82-kDa protein was produced. Immunoprecipitation experiments show that 1A5 recognizes an epitope located on vp5, a tentative trypsin cleavage fragment of the 82-kDa protein. The functional and antigenic topography on the 82-kDa protein is discussed in relation to vp4 of group A rotavirus.