A serological comparison of bovine coronavirus strains

Two bovine coronavirus (BCV) strains from diarrheic calf faeces were adapted to grow in HRT 18 cells and compared in immunofluorescence (IF), haemagglutination inhibition (HAI) and neutralisation (NT) tests with three other strains of BCV and a human coronavirus (HCV) strain obtained from other laboratories. Polyclonal antisera against these 6 viruses were raised in rabbits. No significant differences between viruses were detected by IF. In the HAI test the HCV strain was distinguishable from the 5 BCV strains and serological variation between the BCV strains was shown. HCV could be distinguished by NT test, but all BCV isolates were similar. Two monoclonal antibodies prepared against one of the BCV strains distinguished HCV in all three assays, and detected varying relationships between BCV strains.