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Pushpa Pandiyan, Treg dysfunction in aging oral mucosa, The Journal of Immunology, Volume 204, Issue 1_Supplement, May 2020, Page 235.16, https://doi.org/10.4049/jimmunol.204.Supp.235.16
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Abstract
Aging leads to an increased susceptibility to infections, a phenomenon called immunosenescence. An imbalance between proinflammatory and anti-inflammatory mechanisms is also observed during aging. However, mechanisms of mucosal tissue specific infections and inflammation, and the underlying immune cell alterations in these tissues are incompletely understood. Here our objective was to understand oral mucosal immune cells, especially regulatory T cells, a population of CD4+ T cells that are central to immunomodulation. We infected young (2–3 months) and aged (>18–24months) C57BL/6 mice with a sublingual inoculation of 2 × 107Candida albicans (SC5314) blastospores under anesthesia. We reinfected the mice on day 7 and day 16 after primary infection to mimic recurrent/secondary infections, monitored their weight loss and tongue immunopathology. Control mice were sham infected with PBS. We isolated oral draining cervical lymph nodes (CLN) cells and mouse oral intraepithelial and lamina propria cells (MOIL), and determined the frequency, absolute cell numbers and functions of T and inflammatory CD4 T cells ex vivo before and after infection. We found that aged mice continuously lost weight during the course of the recurrent infections, whereas young mice regained their weight after every infection. Immunosenescent phenotype in aged mice was associated with heightened tongue immunopathology, compared to young mice. Increased oral inflammation phenotype was associated with Treg dysfunctions in local oral tissue. Taken together, our study begins to define T cell dysfunctions and inflammatory processes underlying decline of the immune responses in oral mucosa.
