Enzyme-linked immunosorbent assay for detection of antibody to Treponema hyodysenteriae antigens.

The enzyme-linked immunosorbent assay (ELISA) was evaluated and compared with the microtitration agglutination test for the detection of swine antibody to Treponema hyodysenteriae lipopolysaccharide antigens. Cells of T. hyodysenteriae serotypes 1 and 2 were extracted with hot phenol-water (68 degrees C). The lipopolysaccharide fraction from the aqueous phase was coated on plastic wells at concentrations of 1 micrograms (serotype 1) and 10 micrograms (serotype 2) of carbohydrate per ml. The ELISA was serotype specific when lipopolysaccharide antigens were reacted against sera from convalescent swine. Seroconversion of infected pigs was detectable with the ELISA within 1 to 2 weeks postinoculation and with the microtitration agglutination test 2 to 3 weeks postinoculation. Antibody titers could be detected in convalescent pigs as long as 19 weeks postinoculation by the ELISA and 12 to 13 weeks postinoculation by the microtitration agglutination test. Therefore, the ELISA may be useful for the detection of asymptomatic carriers.