Intracellular localization of Porphyromonas gingivalis thiol proteinase in periodontal tissues of chronic periodontitis patients

Authors

  • R Rautemaa,

    1. Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki and Microbiology Unit of Helsinki University Central Hospital Laboratory Diagnostics, Helsinki
    2. Department of Oral and Maxillofacial Diseases, Helsinki University Central Hospital, Helsinki
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  • A Järvensivu,

    1. Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki and Microbiology Unit of Helsinki University Central Hospital Laboratory Diagnostics, Helsinki
    2. Institute of Dentistry, University of Helsinki, Helsinki and Orton Research Institute and the Orthopedic Hospital of Invalid Foundation, Helsinki, Finland
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  • K Kari,

    1. Institute of Dentistry, University of Helsinki, Helsinki and Orton Research Institute and the Orthopedic Hospital of Invalid Foundation, Helsinki, Finland
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  • J Wahlgren,

    1. Institute of Dentistry, University of Helsinki, Helsinki and Orton Research Institute and the Orthopedic Hospital of Invalid Foundation, Helsinki, Finland
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  • A DeCarlo,

    1. Departments of Periodontics and Oral Biology, University of Alabama at Birmingham, Birmingham, AL, USA
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  • M Richardson,

    1. Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki and Microbiology Unit of Helsinki University Central Hospital Laboratory Diagnostics, Helsinki
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  • T Sorsa

    1. Department of Oral and Maxillofacial Diseases, Helsinki University Central Hospital, Helsinki
    2. Institute of Dentistry, University of Helsinki, Helsinki and Orton Research Institute and the Orthopedic Hospital of Invalid Foundation, Helsinki, Finland
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Dr Riina Rautemaa, Department of Bacteriology and Immunology, Haartman Institute, PO Box 21 (Haartmaninkatu 3), FIN-00014 University of Helsinki, Helsinki, Finland. Tel.: 358 9 1912 6377, Fax: 358 9 1912 6382, E-mail: riina.rautemaa@helsinki.fi

Abstract

Objectives: Porphyromonas gingivalis is a significant periodontal pathogen that has been shown in vitro to be able to invade gingival epithelial cells and grow intracellularly. The aim of the present study was to detect P. gingivalis in gingival tissues from chronic periodontitis (CP) patients.

Materials and methods:  Monoclonal antibodies specific to a cell membrane-bound thiol proteinase of P. gingivalis were used to detect the microbe in gingival tissues of CP patients (n = 13) by immunohistochemistry. The presence of P. gingivalis was also analysed by polymerase chain reaction (PCR).

Results:  Immunohistochemical analysis of the periodontal tissues revealed positive staining for P. gingivalis thiol proteinase in 11 of the 13 patients. Positive staining was mainly located intracellularly in the perinuclear region of the cytoplasm in the periodontal epithelial cells and it could be detected throughout the whole depth of both pocket and oral epithelium. The sensitivity of immunohistochemistry was found to be comparable with that of PCR.

Conclusions:  Our results provide in vivo evidence of the ability of P. gingivalis to enter human gingival epithelial cells. Intracellular localization of P. gingivalis contributes to its evasion of the host immune surveillance and eventually increases its resistance to conventional treatments of periodontal diseases.

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