Abstract: Actinobacillus actinomycetemcomitans has frequently been implicated in juvenile periodontitis. The present monoclonal antibodies are specific to Actinobacillus actinomycetemcomitans. The present monoclonal antibodies are typically employed as reagents which include an inert carrier, preferably a liquid, such as buffered saline solution and a preservative. The carrier compositions are suitably selected to provide for the proper dispersal of bacteria, and to preserve the integrity of antigens and supplemental structures. The selection of the proper carrier is especially important in the detection in mixtures which include bacteria which produce large amounts of autolyltic enzymes such as B. gingivalis. The monoclonal antibodies of the present invention are useful in clinical testing and differentiating antigens in the gingival or subgingival sera.