Production and characterisation of monoclonal antibodies to the principle sonicate antigens of Porphyromonas gingivalis w50

Protein antigens from whole cell sonicates of Porphyromonas gingivalis W50, previously shown to be discriminatory antigens for patients with adult periodontitis, were purified using SDS‐PAGE. Electroeluted proteins were used to immunize mice for the production of monoclonal antibodies (mAbs). A combination of enzyme‐linked immunosorbent assay (ELISA) and Western blotting were used to screen hybridoma supernatants for mAbs. MAbs were successfully raised against Mr 115 000, Mr 55 000 and Mr 47 000 antigens together with a second Mr 55 000 polypeptide which was a contaminant of the Mr 55 000 antigen. No immunological cross‐reactivity was found between these four proteins. The mAbs were used to examine the distribution of these antigens among fifteen P. gingivalis strains together with related oral bacteria using immunostaining of dot blots and Western blots. The antigens were confined to P. gingivalis with the Mr 115 000 and Mr 47 000 antigens being present in all strains tested . The distribution of the Mr 55 000 antigens were slightly more restricted: one Mr 55 000 (outer membrane location) was present in nine of the fifteen P. gingivalis strains tested, while the other Mr 55 000 (location unknown) was only absent from one strain. Whole cell ELISA demonstrated that the Mr 115 000 and the outer membrane Mr 55 000 antigen possess epitopes which are located on the surface of the bacterium.