SPECIES-SPECIFICITY OF MONOCLONAL-ANTIBODIES RECOGNIZING PREVOTELLA-INTERMEDIA AND PREVOTELLA-NIGRESCENS

Prevotella intermedia and Prevotella nigrescens are not easily disting uished, making it difficult to assess their roles in disease. This stu dy examined the specificity of three monoclonal antibodies (mAbs) for these species. Differentiation between P. intermedia (13 isolates) and P. nigrescens (24 isolates) was by the electrophoretic mobility of th eir malate and glutamate dehydrogenase enzymes or by DNA homology grou ping. All P. intermedia reacted strongly with mAb 40BI3.2.2 whereas P. nigrescens strains did not. Monoclonal antibodies 37BI6.1 and 39BI1.1 .2 recognised all strains of both species but most P. nigrescens react ed weakly with mAb 39BI1.1.2. Monoclonal antibody 40BI3.2.2 therefore recognises an antigen specific for P. intermedia but not P. nigrescens and provides an easy and reliable means of distinguishing between the se species. Three vaginal isolates identified biochemically as P. inte rmedia had enzymes with mobilities corresponding to neither P. interme dia nor P. nigrescens. These isolates were not recognised by mAbs 39BI 1.1.2 or 40BI3.2.2 and may represent an undescribed taxon within this group of organisms.