Investigation of antigenic expression of Bacteroides fragilis by immunogold labelling and immunoblotting with a monoclonal antibody

Abstract Electron microscopy and immunogold labelling with monoclonal antibody (McAb) Bfl identified an antigen expressed on some in vitro and in vivo grown Bacteroides fragilis NCTC9343 cells.
Immunoprecipitation with this McAb was used to enrich for B. fragilis NCTC9343 cells expressing the Bfl antigen. The McAb Bfl bound to an epitope close to the surface of the outer membrane, but the fibrous capsular network radiating from the bacterial surface was not labelled. Analysis by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting identified 3 high- M _r bands which resisted heating and protease digestion but were partially sensitive to sodium periodate treatment.