Biochemical and immunochemical characterisation of strains of Treponema hyodysenteriae

The protein composition of 18 clinical isolates of Treponema hyodysenteriae from pigs with swine dysebtery in Australia were compared by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunublot analysis. Coomassie Blue stained SDS-PAGE-profiles of whole cell and outer membrane (OM) proteins demonstrated the same gel pattern among the T. hyodysenteriae isolates, particularly the OM proteins in the molecular mass (M r) range of 30 kDa to 40 kDa. The T. hyodysenteriae isolates were categorised into two distinct groups (A and B) based on the strain-variability in the 37 kDa OM protein. Immunoblotting of whole cell proteins after SDS-PAGE using serum from rabbits and pigs immunised with known T. hyodysenteriae serotypes revealed a number of common immunoreactive bands in all isolates. LPS typing of the T. hyodysenteriae isolates by immunoblotting with the rabbit antiserum revealed one additional serotype emphasising the LPS heterogeneity among the strains isolated from geographic locations in Australia, Great Britain and the U.S.A. Immunoblotting of the OM preparations revealed several common immunoreactive polypeptides corresponding to M r values of 34 kDa to 30 kDa among the T. hyodysenteriae and T. innocens isolates but a distinct 39 kDa found only in the T. hyodysenteriae isolates. Trypsin proteolysis of intact T. hyodysenteriae cells caused selective loss of these and other major abundant proteins identifying the location of the 39 kDa, 36 kDa,and 30 kDa proteins on the cell surface and suggesting a possible role of these proteins in the pathogenesis of swine dysentery.