The cell-surface components of Bacteroides thetaiotaomicron as coating antigens in ELISA test.

Cell-surface antigens were extracted out of three Bacteroides thetaiotaomicron strains of different origin. Lipopolysaccharides, their fractions, L1 preparations and capsular antigen were obtained. All substances were tested as coating antigens in ELISA test against antibacterial rabbit immune sera. The highest absorbances were observed with lipopolysaccharides (LPS), their polysaccharide fractions (PS) and capsular material (CPS). Lipopolysaccharides after nuclease treatment (N-LPS), free from nucleic acids, were more active than crude phenol-water extracts (PW-LPS).