Institution Granting Degree
Iowa State University
Outer membrane proteins (OMP) of Treponema hyodysenterieae were extracted by a number of methods. Extraction with N-lauryl sarcosine, followed by SDS-PAGE allowed for the differentiation of T. hyodysenteriae from T. innocens and showed profiles of T. hyodyseneriae were stable between serotypes or after many in vitro passages. After growth with an iron chelator, desferal mesylate, a new OMP was visible after SDS-PAGE which had a m.w. of 70kDa. OMP profiles of T. innocens were heterogeneous.
Western blot analysis of OMP extracts was used to examine the immune response of swine to infection or immunization with T. hyodysenteriae. Pigs were immunized with sarcosine extracted OMPs and protected from challenge. Immune and convalescent swine serum contained antibody reactive to antigens not recognized by antibodies from non-protected, diseased pigs. Antibody reacts with antigens which migrate to 14 and 19kDa. The 14 and 19kDa antigens may be protective and they may be virulence factors of the organism. These antigens were sensitive to proteinase K and lipase. Protective serum had antibodies to LPS and hemolysin which were isolated from T. hyodysenteriae. Lipopolysaccharide and hemolysin from T. hyodysenteriae migrated in the area of the 14 and 19kDa protective antigens and may be the protective antigens. Colonic antibody and antibody from protective sows milk reacted with several OMP antigens, including the suspected protective antigens.
Finally, monoclonal antibodies (MAB) which react with T. hyodysenteriae were developed. Serotype specific MAB was shown to passively protect mice from subsequent challenge with homologous but not heterologous T. hyodysenteriae. A non-serotype specific MAB did not protect mice. The LPS molecule is the basis for serospecificity. These results indicate that LPS may be an important virulence attribute of T. hyodysenteriae and that serum, colonic, or milk antibody to this antigen may be important in protecting pigs from swine dysentery.