Th17-to-Tfh plasticity during periodontitis limits disease pathology

Area of Science:

• Immunology
• Microbiology
• Periodontal disease research

Background:

• Th17 cell plasticity is implicated in autoinflammatory diseases.
• Periodontitis involves Th17 cells, but their plasticity in this context is unknown.

Purpose of the Study:

• To investigate Th17 cell functional plasticity during periodontitis.
• To determine the role of Th17 cell plasticity in periodontitis pathology.

Main Methods:

• Utilized IL-17 fate-mapping in a periodontitis model.
• Analyzed T cell cytokine production and phenotype in gingiva and draining lymph nodes.
• Assessed the impact of Th17-to-Tfh plasticity on periodontal bone loss, IgG levels, and oral microbiota.

Main Results:

• Gingival Th17 cells largely retained IL-17A production during periodontitis.
• IL-17-expressing T cells in draining lymph nodes exhibited plasticity, differentiating into Tfh-like cells.
• This Th17-to-Tfh plasticity, dependent on IL-6, was protective, limiting bone loss and controlling oral commensal bacteria.

Conclusions:

• Th17 cell plasticity occurs in periodontitis, specifically a Th17-to-Tfh cell switch in lymph nodes.
• This plasticity serves a protective role by enhancing oral immunity and limiting periodontal disease.
• A subset of pathogenic Th17 cells can acquire a protective function through plasticity.