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CD4+CD25+ T cells regulate airway eosinophilic inflammation by modulating the Th2 cell phenotype
Zeina Jaffar1, Thamayanthi Sivakuru, Kevan Roberts
1Center for Environmental Health Sciences, University of Montana, Missoula, MT 59812, USA. zjaffar@spahs.umt.edu
Journal of Immunology (Baltimore, Md. : 1950)
|March 9, 2004
Summary
Regulatory T cells (Tregs) suppress Th2 airway inflammation by modulating Th2 cell phenotype. Depleting Tregs enhances eosinophilic inflammation, despite reduced Th2 cytokines, highlighting Tregs
Area of Science:
- Immunology
- Respiratory Medicine
- Allergy and Asthma
Background:
- Th2-mediated airway inflammation is a hallmark of allergic asthma.
- The role of CD4+CD25+ regulatory T cells (Tregs) in Th2 responses remains incompletely understood.
Purpose of the Study:
- To investigate the influence of Ag-specific CD4+CD25+ regulatory T cells on Th2-mediated airway inflammation.
- To elucidate the mechanisms by which Tregs modulate Th2 cell differentiation and function.
Main Methods:
- Utilized TCR-transgenic (DO11.10) mice to isolate and study CD4+CD25+ T cells.
- Depletion of CD4+CD25+ T cells prior to Th2 differentiation.
- Adoptive transfer of CD4+CD25- derived Th2 cells and unfractionated CD4+ Th2 cells into BALB/c mice.
- Ovalbumin (OVA) inhalation challenge to induce airway inflammation.
- Quantification of Th2 cytokines (IL-4, IL-5, IL-13), IL-10, IFN-gamma, and eotaxin in bronchoalveolar lavage fluid (BALF).
Main Results:
- Depletion of CD4+CD25+ T cells reduced Th2 cytokine (IL-4, IL-5, IL-13) expression during Th2 differentiation.
- CD4+CD25- derived Th2 cells exhibited reduced IL-10 production but maintained Th2 polarization (no IFN-gamma).
- Adoptive transfer of CD4+CD25- derived Th2 cells induced heightened airway eosinophilic inflammation and elevated eotaxin levels in BALF, associated with reduced IL-10.
- This altered Th2 phenotype persisted in vivo despite repeated OVA exposure.
Conclusions:
- CD4+CD25+ regulatory T cells play a critical role in modulating Th2-mediated pulmonary inflammation.
- Tregs suppress the development of a highly eosinophil-promoting Th2 phenotype, potentially via IL-10 production.
- These findings reveal a novel mechanism by which Tregs regulate allergic airway inflammation.