Vγ1+ T Cells and Tumor Necrosis Factor-Alpha in Ozone-Induced Airway Hyperresponsiveness

Abstract

gammadelta T cells regulate airway reactivity, but their role in ozone (O3)-induced airway hyperresponsiveness (AHR) is not known. Our objective was to determine the role of gammadelta T cells in O3-induced AHR. Different strains of mice, including those that were genetically manipulated or antibody-depleted to render them deficient in total gammadelta T cells or specific subsets of gammadelta T cells, were exposed to 2.0 ppm of O3 for 3 hours. Airway reactivity to inhaled methacholine, airway inflammation, and epithelial cell damage were monitored. Exposure of C57BL/6 mice to O3 resulted in a transient increase in airway reactivity, neutrophilia, and increased numbers of epithelial cells in the lavage fluid. TCR-delta(-/-) mice did not develop AHR, although they exhibited an increase in neutrophils and epithelial cells in the lavage fluid. Similarly, depletion of gammadelta T cells in wild-type mice suppressed O3-induced AHR without influencing airway inflammation or epithelial damage. Depletion of Vgamma1+, but not of Vgamma4+ T cells, reduced O3-induced AHR, and transfer of total gammadelta T cells or Vgamma1+ T cells to TCR-delta(-/-) mice restored AHR. After transfer of Vgamma1+ cells to TCR-delta(-/-) mice, restoration of AHR after O3 exposure was blocked by anti-TNF-alpha. However, AHR could be restored in TCR-delta(-/-)mice by transfer of gammadelta T cells from TNF-alpha-deficient mice, indicating that another cell type was the source of TNF-alpha. These results demonstrate that TNF-alpha and activation of Vgamma1+ gammadelta T cells are required for the development of AHR after O3 exposure.