Colocalization of Porphyromonas gingivalis with CD4+ T cells in periodontal disease

Abstract

Porphyromonas gingivalis, an anaerobic, asaccharolytic gram-negative bacterium, is a causative agent in chronic periodontitis. It has many virulence factors that facilitate infection of the gingiva, but little is known about the local immune cells that respond to this bacterium. The aims of this study were to quantify P. gingivalis in gingival biopsies from patients with periodontitis using laser capture microdissection (LCM) plus qRT-PCR and to determine the phenotype of immune cells associated with the bacteria using immunofluorescence. The presence of P. gingivalis was confirmed in periodontitis gingival tissue from 10 patients, and differences in bacterial distribution in the epithelium and connective tissue with or without inflammatory infiltrates were observed. Immune cells found in the biopsy tissues, including CD20+ mature B cells and CD138+ plasma cells, were associated with the Th2-type immune response. Most P. gingivalis was in direct contact with CD4+ T cells. This study revealed for the first time the colocalization of P. gingivalis with immune cells. Use of LCM combined with qRT-PCR enabled quantitative analysis of bacteria in a selected area of a biopsy sample without any tissue degradation. Observation of the immune cells associated with these bacteria was also performed by immunofluorescence.

T‐ and B‐cell subsets in periodontitis

“…Immune cells (such as CD20 + mature B‐cells and CD138 + plasma cells) found in tissue biopsies were associated with the T‐helper 2‐type immune response. Most P. gingivalis was in direct contact with CD4 + T‐cells . Together with the findings that P. gingivalis induces RANKL and prostaglandin E 2 in T‐cells, these results may explain the bone‐resorption mechanisms initiated by P. gingivalis in periodontitis .…”

Expression of peptidylarginine deiminase‐2 and ‐4, citrullinated proteins and anti‐citrullinated protein antibodies in human gingiva

“…While citrullinated proteins were located in the gingival tissues, and PAD‐2 and PAD‐4 (both protein and mRNA) were also detected, it cannot be assumed that no other PADs were involved in the citrullination process. P. gingivalis is strongly associated with periodontitis and may infiltrate the gingival tissues . Thus, PPAD could be present in inflamed periodontal tissues.…”

Gingival Perfusion and Tissue Biomarkers During Early Healing of Postextraction Regenerative Procedures: A Prospective Case Series

“…Despite the advantages of LCM in studying tissue/cell-specific biology, the use of this technique has been limited in clinical periodontal studies. 29, 30 …”