Generation of gingival T cell lines/clones specific with Porphyromonas gingivalis pulsed dendritic cells from periodontitis patients

Objectives and background: It is well documented that in periodontitis lesions, most infiltrated gingival T cells are antigen‐specific memory T cells. These cells play an important role as regulators and effector cells in the pathogenesis of periodontitis. In this study, we used dendritic cells (DCs) as antigen‐presenting cells to generate human gingival T cell lines and clones specific for Porphyromonas gingivalis from periodontitis patients.Methods: Autologous DCs were derived from the patients' adherent monocytes using granulocyte‐macrophage colony‐stimulating factor and interleukin (IL)‐4. Lymphocytes were isolated from gingival biopsies using collagenase enzyme digestion and the number was increased by subsequent culturing in IL‐2‐containing medium. T cells were then negatively sorted using flow cytometry, cocultured with P. gingivalis‐pulsed DCs and subsequently expanded in the culture medium containing IL‐2. T cells were kept viable and active by periodic exposure to antigen‐pulsed DCs. The specificity of the T cell lines was tested against four plaque bacteria: P. gingivalis, Actinobacillus actinomycetemcomitans, Prevotella intermedia and Actinomyces viscosus. The established T cell lines were then cloned. Three P. gingivalis‐specific T cell lines and 12 gingival T cell clones were generated. They all showed good specificity against P. gingivalis but not to other plaque bacteria.Results: All T cell clones were positive for CD4 and the majority of them produced interferon gamma, but a minimal or negligible amount of IL‐5.Conclusions: The data obtained clearly showed that monocyte‐derived DCs could be used as powerful antigen‐presenting cells to generate antigen‐specific T cells from periodontitis tissues.