FOXP3+ Regulatory T Cells Require TBET to Regulate Activated CD8+ T Cells During Recovery from Influenza Infection

Area of Science:

• Immunology
• Respiratory Medicine
• Virology

Background:

• FOXP3+ regulatory T (Treg) cells are crucial for resolving lung inflammation and restoring homeostasis after viral infections.
• The precise molecular mechanisms and cellular targets of Treg cells in this context are not fully understood.
• Understanding Treg cell function is vital given ongoing clinical trials for Treg cell transfer therapy in respiratory viral infections.

Purpose of the Study:

• To determine the causal role of Treg cells in regulating CD8+ T cell responses during influenza infection recovery.
• To identify the molecular requirements for Treg cell-mediated regulation of CD8+ T cells.
• To investigate the impact of Treg cells on the generation and programming of lung CD8+ T cells.

Main Methods:

• Causal experiments in mouse models of influenza infection.
• Genetic strategies combined with adoptive transfer techniques.
• Analysis of CD8+ T cell populations, including tissue-resident memory T (Trm) cells.

Main Results:

• Treg cells are essential for controlling the numbers of activated CD8+ T cells during influenza recovery.
• The transcription factor T-bet is required for Treg cells to regulate CD8+ T cells.
• Treg cells are not essential for generating CD8+ lung Trm cells but influence their transcriptional programming.

Conclusions:

• Treg cells play a critical role in modulating the CD8+ T cell response following influenza infection.
• T-bet is a key molecular mediator of Treg cell function in regulating CD8+ T cells.
• These findings clarify Treg cell functions in the adaptive immune response to respiratory viral infections.