Antigen presentation in the lung.

Studies from our laboratory and elsewhere have implicated populations of dendritic cells in lung and airway tissues as key regulators of both qualitative and quantitative aspects of T cell responses to local antigenic challenge. Under steady state conditions, they are specialized for uptake of antigen, and require additional maturation signals for full expression of their T cell-stimulating activity. Their functional phenotype appears to be controlled via a complex series of interactions with both bone marrow-derived, mesenchymal, and possibly neuroendocrine cells; failure(s) in one or more of these regulatory interactions may be important etiologic and/or pathogenic factors in a variety of respiratory immunoinflammatory disease.