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


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.
Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki and Microbiology Unit of Helsinki University Central Hospital Laboratory Diagnostics, Helsinki, Finland. riina.rautemaa@helsinki.fi
R
R
Rautemaa
A
A
Järvensivu
K
K
Kari
J
J
Wahlgren
A
A
DeCarlo
M
M
Richardson
T
T
Sorsa
D000911:Antibodies, Monoclonal; D001425:Bacterial Outer Membrane Proteins / Q000032:analysis; D002467:Cell Nucleus / Q000201:enzymology / Q000382:microbiology; D002908:Chronic Disease; D004396:Coloring Agents; D003546:Cysteine Endopeptidases / Q000032:analysis*; D003593:Cytoplasm / Q000201:enzymology / Q000382:microbiology; D004847:Epithelial Cells / Q000201:enzymology / Q000382:microbiology; D005260:Female; D005881:Gingiva / Q000382:microbiology* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D042541:Intracellular Space / Q000201:enzymology / Q000382:microbiology*; D008297:Male; D008875:Middle Aged; D010514:Periodontal Pocket / Q000382:microbiology / Q000473:pathology; D010518:Periodontitis / Q000382:microbiology* / Q000473:pathology; D016133:Polymerase Chain Reaction; D016966:Porphyromonas gingivalis / Q000166:cytology / Q000201:enzymology*
D000911:Antibodies, Monoclonal; D001425:Bacterial Outer Membrane Proteins; D004396:Coloring Agents; D003546:Cysteine Endopeptidases