T cells, teeth and tissue destruction - what do T cells do in periodontal disease?

The microbial plaque biofilm resides adjacent to the tissue-destructive inflammatory infiltrate in periodontitis. Although not sufficient, this biofilm is necessary for this inflammatory response. Patients with periodontitis generate antibodies specific for bacteria in the biofilm - although the role of these antibodies is not clear, there is, undoubtedly, an adaptive immune response in periodontitis. T lymphocytes are central to adaptive immunity, and provide help for B cells to generate specific antibodies. T-cell receptor recognition of peptide antigen in the context of major histocompatibility complex can result in T-cell activation. The activation and differentiation of the T-cell can take many forms, and hence numerous types of T cells have been described. The role of adaptive immune responses, and the T-cell component thereof, in periodontitis remains relatively poorly defined. This review aims to broadly summarize findings about T cells and their role in periodontitis, focusing primarily on studies of human disease with a short discussion of some animal studies.