Regulatory T cells in mouse periapical lesions

Area of Science:

• Immunology
• Oral Biology
• Pathology

Background:

• Regulatory T (Treg) cells, a CD4+ FOXP3+ subpopulation, are vital for suppressing immune responses and preventing autoimmune diseases.
• The role of Treg cells in periapical lesions, often resulting from dental pulp infections, has not been fully elucidated.

Purpose of the Study:

• To investigate the induction and infiltration of Treg cells into periapical lesions following dental pulp infection.
• To determine the temporal dynamics of Treg cell accumulation in response to pulpal infection.

Main Methods:

• In situ hybridization (ISH) was employed to detect FOXP3+ cells in periapical lesions at day 21 post-infection.
• FOXP3/GFP knock-in transgenic mice were used for flow cytometry to quantify Treg cell infiltration at days 7, 14, and 21.
• Uninfected periodontal ligament served as a control group.

Main Results:

• ISH confirmed the presence of FOXP3+ cells primarily at the periphery of periapical lesions, with none in uninfected controls.
• Flow cytometry revealed a significant increase in FOXP3+ Treg cells starting between days 7-14 and continuing to day 21 post-infection (0.69% to 0.94% of infiltrate).
• Elevated Treg cell numbers were also observed in draining cervical lymph nodes.

Conclusions:

• Pulpal infection triggers the induction and infiltration of Treg cells into periapical lesions.
• The accumulation of Treg cells in these lesions demonstrates a time-dependent pattern following infection.