Lung infiltrating Foxp3+ regulatory T cell cells are quantitatively and qualitatively different during eosinophilic and neutrophilic allergic airway inflammation but essential to control the inflammation

• Published in: The Journal of immunology (1950) 2017-11, Vol.199 (12), p.3943-3951
• Main Authors: Jang, Eunjung, Nguyen, Quang Tam, Kim, Sohee, Kim, Dongkyun, Nga Le, Thi Hong, Keslar, Karen, Dvorina, Nina, Aronica, Mark A., Min, Booki
• Format: Article
• Language: English
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.1700211

Understanding functions of Foxp3 + regulatory T (Treg) cells during allergic airway inflammation remains incomplete. In this study, we report that during cockroach antigen (CA)-induced allergic airway inflammation Foxp3+ Treg cells are rapidly mobilized into the inflamed lung tissues. However, the level of Treg cell accumulation in the lung was different depending on the type of inflammation. During eosinophilic airway inflammation, ~30% of lung infiltrating CD4 T cells express Foxp3, an indicative of Treg cells. On the contrary, only ~10% of infiltrating CD4 T cells express Foxp3 during neutrophilic airway inflammation. Despite the different accumulation, both the lung inflammation and inflammatory T cell responses were aggravated following Treg cell depletion regardless of the type of inflammation, suggesting regulatory roles of Treg cells. Interestingly, however, the extent to which inflammatory responses are aggravated by Treg cell depletion was significantly greater during eosinophilic airway inflammation. Indeed, lung infiltrating Treg cells exhibit phenotypic and functional features associated with potent suppression. Our results demonstrate that Treg cells are essential regulators of inflammation regardless of the type of inflammation, although the mechanisms employed by Treg cells to control inflammation may be shaped by environmental cues available to those Treg cells.