Immunochemical investigations of antigens isolated from Bacteroides ovatus strain ATCC 8483.

A saline extract (SE) and a phenol/water extract (WL) were prepared from Bacteroides ovatus strain ATCC 8483. A fraction CS was isolated from the culture supernatant. WL was further split by ultracentrifugation into lipopolysaccharide (LPS) and supernatant (L1). Fractions SE, WL, LPS and L1 reacted serologically with homologous antiserum but did not cross-react with antisera against heterologous Bacteroides serotypes. Fraction CS was inactive in haemagglutination, haemagglutination inhibition and immunoelectrophoresis tests. SE, WL, LPS and L1 proved to be serologically heterogeneous. A distinct serological specificity for SE was demonstrated. The serological reactivity in SE and WL was not altered after treatment with proteolytic enzymes yet completely destroyed in WL and partially in SE by sodium metaperiodate. SE, WL, LPS and L1 contained the sugar components rhamnose, fucose, ribose, mannose, galactose, glucose and glucosamine in different molar ratios for each fraction. Galactosamine was found in WL and LPS, uronic acid in WL and L1. Two unidentified aminohexoses were detected in WL, one of which was also detectable in L1 and SE. 2-Keto-3-deoxyaldonic acid was demonstrated in LPS and L1 after strong acid hydrolysis.