A comparison of bovine coronavirus strains using monoclonal antibodies

Eight monoclonal antibodies (MAbs) were raised against a bovine coronavirus (B.C.V.) which had been isolated in Scotland and was designated S2. The MAbs were divided into two groups on the basis of their reactions with S2 virus in indirect immunofluorescence (I.F.), neutralisation and haemagglutination inhibition (H.A.I.) tests. Five of the MAbs were positive by all three tests but failed to bind to proteins in Western immunoblotting experiments. The remaining three MAbs were positive in I.F. tests only, two of which were shown to bind to the 52K nucleocapsid protein by Western immunoblotting. Different patterns of antigen distribution within infected cells were demonstrated when the MAbs were used in the I.F. test. However only minor strain variations were detected by I.F. and H.A.I. tests when the MAbs were tested against each of five cell culture adapted strains of B.C.V. Twenty-nine isolates of B.C.V. have been grown in neonatal calf tracheal organ cultures: attempts are being made to further characterize these isolates.