Porphyromonas gingivalis FDC381 multiplies and persists within human oral epithelial cells in vitro.

Porphyromonas gingivalis FDC381 replication and persistence within KB epithelial cells in vitro were studied by means of an antibiotic protection assay and electron microscopy. Intracellular counts decreased during the first 24 h; showed a threefold increase during the second day, indicating intracellular multiplication; and after 8 days declined to levels approximating 40% of the initial invasion. The ability of P. gingivalis to persist and multiply within epithelial cells may constitute a pathogenic mechanism in periodontal disease.