Production and characterization of monoclonal antibodies against Serpulina hyodysenteriae and S. innocens and their use in serotyping.

Murine monoclonal antibodies (MAbs) directed against serotypes 1, 2, 8, and 9 of Serpulina hyodysenteriae and strain B256 of Serpulina innocens were produced and characterized. A serological classification of 96 field strains of S. hyodysenteriae and 28 field strains of S. innocens isolated from pigs showing clinical signs of swine dysentery was performed by rapid dot enzyme-linked immunosorbent assay (ELISA) with the MAbs. The results indicated that the majority of the field strains of S. hyodysenteriae (69%) belonged to serotypes 8, 1, and 9, whereas only 31% of the S. innocens strains were recognized by MAb 9H7, indicating the presence of antigenic heterogeneity among S. innocens isolates. Rapid dot ELISA with type-specific MAbs was found to be specific, sensitive, and easy to perform and thus to be suitable for routine serotyping of S. hyodysenteriae and S. innocens isolates. This is the first report of MAbs being used for serotyping clinical isolates of S. hyodysenteriae and S. innocens.