Cloning and characterization of Treponema hyodysenteriae antigens and protection in a CF-1 mouse model by immunization with a cloned endoflagellar antigen.

We cloned genes that code for Treponema hyodysenteriae antigens into Escherichia coli with the purpose of identifying protective antigens for vaccine development. Three different genomic libraries were screened with various antisera reactive with T. hyodysenteriae antigens. The cloned antigens and corresponding native T. hyodysenteriae antigens were analyzed for molecular size, serum reactivity, solubility in sarcosine, and segregation during phase partitioning with the nonionic detergent Triton X-114. The results from these analyses suggested that the gene products were components of either the cytoplasmic membrane, periplasm, or endoflagella of T. hyodysenteriae. The cloned antigens were tested as vaccine candidates in a CF-1 mouse model of T. hyodysenteriae infection and immunity. Intraperitoneal injection of crude E. coli extracts containing cloned antigens did not protect mice from challenge. However, serum from mice injected with a crude extract of an E. coli clone which expressed an endoflagellar antigen killed T. hyodysenteriae in vitro. Partially purified preparations of this cloned endoflagellar antigen protected mice against oral challenge with both the homologous serotype (B204) and a heterologous serotype (B234) of T. hyodysenteriae. These results suggest that the endoflagellar proteins could be used as an effective subunit vaccine against T. hyodysenteriae.