Reduced early life mucosal integrity decreases thymic cell counts and increases local, but not thymic regulatory, T cell recruitment: Gut mucosal integrity breach and thymic T cells

Hannah Louise Zakariassen*, Katja Maria Bendtsen, Peter Tougaard, Axel Kornerup Hansen

*Corresponding author for this work

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Abstract

Early life immune gut microbiota contact is critical for regulatory T cell–mediated oral tolerance induction. We induced a mucosal integrity breach with low dextran sulfate sodium dose right after weaning in BALB/c mice along with a standard high dose to study the impact of increased gut microbiota lymphatic tissue contact on the thymus. Both doses increased gut permeability, which caused a short-term generalized thymic involution and regulatory T cell induction in the mesenteric lymph nodes, even in the absence of clinically apparent inflammation in the low-dose group. The thymic regulatory T cells resisted thymic involution. In the low-dose group, we found acutely altered gut mobilization patterns characterized by changed gut-homing marker CD103 expression on mesenteric lymph node CD4+ T cells as well as on mature CD8+ T cells and developing CD4−/CD8− thymocytes. Furthermore, CD218a (IL-18-receptor-a) expression was acutely decreased on both mature CD8+ T cells and regulatory T cells, while increased on the mesenteric lymph node CD8+ T cells, indicating a direct link between the thymus and the mesenteric lymph nodes with CD218a in a functional role in thymic involution. Acute and non-persisting regulatory responses in the mesenteric lymph nodes were induced in the form of a relative regulatory T cell increase. We saw no changes in total thymic regulatory T cells and thus the thymus does not seem to play a major role of in the regulatory immunity induced by increased gut microbiota lymphatic tissue contact around weaning, which in our study primarily was located to the gut.
Original languageEnglish
JournalEuropean Journal of Inflammation
Volume17
Pages (from-to)1-16
ISSN1721-727X
DOIs
Publication statusPublished - 2019

Keywords

  • cytotoxic T cells
  • gut microbiota
  • helper T cells
  • regulatory T cells
  • thymocytes

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