Comparison of gingival and peripheral blood T cells among patients with periodontitis suggests skewing of the gingival T cell antigen receptor Vβ repertoire

The present study investigated the expression of different variable regions of T cell receptor β‐chain (Vβ) among functional subsets of T cells, i.e. CD45RO+ (activated/memory), CD4+ and CD8+in gingiva and peripheral blood of patients with periodontitis. Gingival tissue specimens (n= 25) and peripheral blood were procured from 18 patients with periodontitis during periodontal surgery or extraction. Single‐cell suspensions of gingival tissues were made by enzymatic digestion. These cells were immunofluorescently labeled with a panel of monoclonal antibodies specific for 18 TCR Vβ regions, in concert with markers for various T cell subsets. The cells were then analyzed with 3‐color multivariate flow cytometry. Results demonstrated that a significantly higher proportion of T cells in gingiva expressed Vβ5.2 (0.0005), Vβ6 (0.0007) and Vβ9 (0.003) regions compared to those in peripheral blood. Comparison of CD45RO+ (activated/memory) and CD45RO− (naïve) subsets of gingival T cells revealed differences in the expression of TCR Vβ regions. Vβ5.2 expression was significantly higher among CD45RO+ gingival T cells (p= 0.004), whereas Vβ14 expression was elevated among the CD45RO− subset relative to peripheral blood (p= 0.008). Analysis of TCR Vβ region expression among CD4+ and CD8+ subsets did not reveal any statistically significant differences between gingiva and peripheral blood, although some Vβ regions approached significance. Collectively, these results demonstrate that the T cell repertoire in the gingival compartment differs significantly from that in the peripheral blood. Furthermore, since the skewing of TCR Vβ was observed among naive, as well as activated/memory T cells, it is likely that both developmental and environmental factors are influential in shaping the gingival TCR repertoire in patients with periodontitis. Elucidation of the cause of the skewed expression of T cell receptors in gingiva can provide insights into the specificity of T cells in periodontitis.