Cutting edge: Protective response to pulmonary injury requires gamma deltaT lymphocytes

gamma delta intraepithelial lymphocytes are thought to coordinate responses to pathogens that penetrate the epithelial barrier. To directly test this, mice were inoculated with Nocardia asteroides, At doses that were nonletha l for control mice, gamma delta-deficient mice became severely ill and died within 14 days. Histologic examination of these lungs demonstrated the pre sence of severe tissue damage and unimpeded bacterial growth in the gamma d elta-deficient mice compared with neutrophilic lesions and clearance of the organism in control mice. Interestingly, ozone exposure that targets a com parable lung region also resulted in diffuse epithelial necrosis associated with a similar lack of neutrophil recruitment in gamma delta-deficient mic e. These data demonstrate that gamma delta intraepithelial lymphocytes can protect the host from pathogenic and nonpathogenic insults by targeting the inflammatory response to epithelial necrosis.