Jeffrey Ebersole

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Follicular helper T cells (Tfh) cells are generally considered critical in secondary lymphoid tissues; however, they are also identified in the circulation and in tertiary lymphoid structures in chronic inflammation. Gingival tissues with periodontitis reflect chronic inflammation so genomic footprints of Tfh cells should occur in these tissues and may differ related to aging effects. Methods: Macaca mulatta monkeys were used in a model of ligature-induced periodontitis [adult group (12-23 years of age); young group (3-7 years)]. Gingival tissue and subgingival microbiome samples were obtained at matched healthy sites, sites during ligature-induced disease, and in samples after clinical resolution. Microarray analysis examined Tfh genes (n=40) and the microbiome samples were examined using 16S MiSeq. Results: An apparent increase in the major transcription factor of Tfh cells, BCL6, was found with disease in both adult and young animals, while the master transcription markers of other T cell subsets were either decreased or showed minimal change. A number of the Tfh related genes, including surface receptors, secreted products and transcription factors were also significantly increased during disease. Unique microbial complexes showed patterns of interactions with Tfh genes that differed in health and disease. Conclusions: An increase in Tfh cell responsiveness occurred later in the progression of periodontitis, affected by age and strongly related to specific microbial complexes. The capacity of gingival Tfh cells to contribute to localized B cell activation and active antibody responses, including affinity maturation may be critical for controlling periodontal lesions and contributing to limiting and/or resolving the lesions.