M Katoh1, S Saito, H Takiguchi, Y Abiko. 1. Department of Biochemistry, Nihon University School of Dentistry at Matsudo, Chiba, Japan.
Abstract
BACKGROUND: We have cloned the gene for a 40-kDa outer membrane protein (40-kDa OMP) from Porphyromonas gingivalis 381. The recombinant (r)40-kDa OMP has become the subject of considerable interest because of its potential role in the development of a vaccine useful for passive immunization. To develop such a vaccine, it is essential to fully understand the functions of anti-r40-kDa OMP antibody in the host defense against P. gingivalis. To that end, we developed a panel of monoclonal antibodies by immunizing mice with purified r40-kDa OMP. The objective of this study was to determine the bactericidal activity on P. gingivalis by the IgG1 monoclonal antibody Pg-ompA2. METHODS: Bacterial growth measurement, a complement-mediated anti-P. gingivalis assay based on [3H]thymidine uptake, and a 14C-release assay were performed to test the bactericidal activity of Pg-ompA2 to P. gingivalis. RESULTS: In the presence of complement, Pg-ompA2 was lethal to P. gingivalis 381 as well as to the more virulent P. gingivalis strains, including ATCC 53977 and W83. Using component-deficient complement, we determined that Pg-ompA2 killed P. gingivalis by activating both the classical and alternative complement pathways. CONCLUSIONS: Pg-ompA2 has an in vitro complement-mediated bactericidal activity to P. gingivalis. Pg-ompA2 may contribute to the development of a local immunotherapy that can be applied in the gingival crevice of a patient with P. gingivalis-related periodontitis, or be a vaccine candidate.
BACKGROUND: We have cloned the gene for a 40-kDa outer membrane protein (40-kDa OMP) from Porphyromonas gingivalis 381. The recombinant (r)40-kDa OMP has become the subject of considerable interest because of its potential role in the development of a vaccine useful for passive immunization. To develop such a vaccine, it is essential to fully understand the functions of anti-r40-kDa OMP antibody in the host defense against P. gingivalis. To that end, we developed a panel of monoclonal antibodies by immunizing mice with purified r40-kDa OMP. The objective of this study was to determine the bactericidal activity on P. gingivalis by the IgG1 monoclonal antibody Pg-ompA2. METHODS: Bacterial growth measurement, a complement-mediated anti-P. gingivalis assay based on [3H]thymidine uptake, and a 14C-release assay were performed to test the bactericidal activity of Pg-ompA2 to P. gingivalis. RESULTS: In the presence of complement, Pg-ompA2 was lethal to P. gingivalis 381 as well as to the more virulent P. gingivalis strains, including ATCC 53977 and W83. Using component-deficient complement, we determined that Pg-ompA2 killed P. gingivalis by activating both the classical and alternative complement pathways. CONCLUSIONS:Pg-ompA2 has an in vitro complement-mediated bactericidal activity to P. gingivalis. Pg-ompA2 may contribute to the development of a local immunotherapy that can be applied in the gingival crevice of a patient with P. gingivalis-related periodontitis, or be a vaccine candidate.
Authors: T Kobayashi; K Yamamoto; N Sugita; A B van Spriel; S Kaneko; J G van de Winkel; H Yoshie Journal: Infect Immun Date: 2001-05 Impact factor: 3.441