Characteristics of Prevotella intermedia-specific CD4+ T cell clones from peripheral blood of a chronic adult periodontitis patient.

Periodontitis is a chronic destructive inflammatory disease associated with periodontopathic bacteria. In addition, autoantigens such as collagen and heat shock proteins (hsp) have been suggested to play a role. Established periodontal lesions are characterized by dense infiltrations of immune cells such as cytokine-producing CD4+ and CD8+ T cells. CD4+ T cells specific for Prevotella intermedia can be isolated from lesional gingiva, suggesting an active role for CD4+ T cells in the response to this bacterium. We therefore investigated the characteristics of a panel of 13 P. intermedia-specific CD4+ T cells generated from the peripheral blood of a patient with chronic adult periodontitis. All 13 P. intermedia-specific CD4+ T cells recognized the antigens in the context of HLA-DR. The T cell clones were mainly classified as Th0, producing comparable amounts of interferon-gamma (IFN-gamma) and IL-4, and Th2, producing high amounts of IL-4 and almost no IFN-gamma. None of the P. intermedia-specific T cell clones recognized antigens of the periodontopathic bacteria Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis and of the autoantigens collagen and hsp. The reactivity profile of the T cell clones to size-fractionated cell envelope antigens of P. intermedia indicated that P. intermedia-specific CD4+ T cell clones recognize probably five different antigen specificities in the context of the MHC class II molecules, DR7 or DR15. These results suggest that a broad panel of cell-associated protein antigens play a role in the induction of P. intermedia-specific CD4+ T cell response.