Adaptation of the viral haemorrhagic disease virus of rabbits to the DJRK cell strain.

Liver emulsion of rabbits which had died of viral haemorrhagic disease (VHD) was inoculated onto DJRK cell culture. After two passages, specific cytopathic effect was observed. Immunofluorescence was found in the nucleus at the early stage of infection and later also in the cytoplasm. The virus propagated in cell culture at the fifth, tenth and sixteenth passages was found to cause typical VHD. Electron microscopy showed that there were numerous virions in the infected cells. The cultured virus, inactivated with formaldehyde, could elicit haemagglutination inhibition antibodies in the inoculated rabbits and protect them against the challenge of virulent VHD virus.