Characterization and differentiation of a soluble lipopolysaccharide type antigen from Treponema hyodysenteriae.

Abstract

Whole cells of T. hyodysenteriae serotypes 1-7, avirulent T. hyodysenteriae serotypes 1 and 2, and 5 strains of T. innocens were chemically extracted to selectively remove a lipopolysaccharide-like substance (LPSLS). The different LPSLS were analyzed electrophoretically, immunologically, and chemically. SDS-PAGE demonstrated migratory differences that were unique for individual serotypes/strains. Additional differences were observed during attenuation which resulted in reduced mobility of upper molecular weight components. Western blotting with hyper-immunized rabbit serum (HRS) against serotype 1, 2, and 6 whole cell bacterins produced homologous and heterologous reactions with serotype specific LPSLS. Rabbit antisera to serotypes 3, 4, 5, and 7 whole cell bacterins produced only homologous reaction to the LPSLS. Convalescent-phase swine sera (CSS) against serotype 1 disease showed only homologous reaction to the LPSLS. Convalescent-phase swine sera against serotype 2 produced both homologous and heterologous reaction to the LPSLS. Antigenicity was recognized by HRS and CSS to the hydrophobic and hydrophilic components of acid hydrolyzed LPSLS. Thin layer chromatography (TLC) of the hydrophobic portion demonstrated the presence of a spot with an Rf of 0.18 that correlates with nonpathogenicity. Gas chromatography (GC) analysis of the carbohydrate content of the LPSLS revealed the presence of glucose, galactose, N-acetyl neuraminic acid, N-acetyl glucosamine, and N-acetyl galactosamine. 2-keto-3-deoxyoctulonate (KDO) and L-glycero-D-manno-heptose were absent. The LPSLS from T. hyodysenteriae was found to have low anticomplement activity in comparison with LPS. The LPSLS from T. innocens had one half the activity of LPS. T. hyodysenteriae LPSLS demonstrated comparable activity to LPS in inducing Ia expression by macrophages. The LPSLS from T. innocens was unable to stimulate expression of a molecules on macrophages.