Establishment of peripheral blood and gingival T lymphocyte clones responsive to Porphyromonas gingivalis

T cells are central to the immune response to infection and studies have indicated a local immunoregulatory imbalance may exist in human periodontal disease. Since Porphyromonas gingivalis is generally recognized as a major periodontopathogen, the aim of this study was to establish T cell lines and clones specific to P. gingivalis from the gingival tissues and peripheral blood of P. gingivalis--infected subjects. Two subjects were selected from two groups of individuals (one from each group) established on the basis of P. gingivalis in their plaque and the presence of serum antibodies which react with P. gingivalis antigens. The two groups differed however in their clinical susceptibility (adult periodontitis) or resistance (gingivitis) to periodontal breakdown. The mean ages +/- standard error of the mean of the two groups were 47.9 +/- 2.2 and 49.6 +/- 3.7, respectively, so that resistance in the gingivitis group was related to the age of the subjects. T cell lines and clones were established from the peripheral blood of one patient from each of the two groups and also from the gingival tissues of the same periodontitis subject. This study has demonstrated the capability of establishing P. gingivalis-specific T cell lines and clones from P. gingivalis-infected subjects and FACS analysis of the T cell receptor variable regions demonstrated that the clones were indeed monoclonal. The CD4:CD8 ratios of the peripheral blood-derived T cell lines were 1.2 and 0.4 for the gingivitis-derived line and the periodontitis-derived line, respectively, thus supporting the clinical differences displayed by the two subjects.