Expression of receptor β-chain variable region by T cells in human periodontal disease

Abstract

T cells play a major part in the immune response in periodontal diseases. In order to determine any selective T-cell receptor (TCR) β-chain variable region (Vβ) usage in the infiltrates of healthy/ gingivitis (H/G) and adult periodontitis (AP), cells were extracted from gingival biopsies, the CD4 and CD8 cells stained with antibodies to eight Vβ regions, and two-colour flow cytometry used to analyse the data. The frequencies of CD4 and CD8 cells expressing each of the TCR-Vβ families varied from 0 to 46% between individuals. A high percentage of CD4 and CD8 cells expressed the Vβ 13 family in several AP biopsies, but, in a number of H/G tissues, a high percentage of T cells expressed up to three families including the Vβ 13 region, these varying from individual to individual. The mean results showed a significantly greater percentage of Vβ 5.2–3-positive CD4 cells ( p = 0.003) and Vβ 5.1- and 5.2–3-positive CD8 cells ( p = 0.003 and 0.025, respectively) isolated from H/G than AP tissues. The percentage of Vβ 3.1-positive CD4 cells extracted from H/G tissues was also higher but not quite significant at the 0.05 level ( p = 0.051). Sections of gingival tissue in biopsies from H/G and AP were stained in situ; there were no significant differences in the mean expression of Vβ 3.1-, 5.1- or 5.2–3-positive cells. A second aim was to determine the effect of Porphyromonas gingivalis on the TCR repertoire. There were no differences in the mean percentage of CD4 or CD8 cells expressing the eight TCR-Vβ regions between the two groups after stimulation in vitro with P. gingivalis outer-membrane antigens. There was, however, a trend towards a decrease in the percentage of positive CD4 and CD8 T cells after culture with the antigen. This was significant for CD4 cells from H/G expressing the Vβ 5.1 and 5.3 TCRs ( p = 0.032 and p = 0.038, respectively). This trend was not evident for Vβ 5.2–3-positive CD4 cells or Vβ 5.1-positive CD8 cells isolated from both H/G and AP nor for Vβ 3.1-positive CD8 cells from AP. The results show that there may be restricted Vβ usage in gingival tissues, particularly in H/G tissues. The Vβ 5 and 3.1 families may be selected for in the gingival tissues and may also be involved in P. gingivalis activation.