Interleukin 2 (IL-2) production and expression of its membrane- bound receptor (IL-2R) are critical steps in the T-cell activation and clonal expansion that occurs in delayed-type hypersensitivity (DTH) reactions. A classic example of these DTH reactions are pulmonary granulomatous diseases, which are often highly destructive lesions that may require potent anti-inflammatory agents for effective treatment, these agents frequently compromise the patient's immunologic integrity. IL-2 is an important lymphokine in the pathogenesis of DTH reactions. Elucidation of regulatory mechanisms of IL-2 and IL-2R will lead to a better understanding of these diseases, as well as the mechanism, whereby IL-2 regulates DTH responses. Studies will begin with the effects of arachidonic acid metabolites on IL-2 production by the cloned human T-cell line Jurkat and the level of regulation addressed by quantitating IL-2 production and mRNA expression. Further studies will use a well-characterized model of T-cell-mediated synchronous granulomas, induced by embolization of Schistosoma mansoni eggs to the pulmonary vasculature. Changes in IL-2 production and IL-2R expression and their respective mRNA levels by cultured granuloma lymphocytes will be quantitated during the evolution of these lesions. Pharmacologic studies directed at the manipulation of cultured granuloma lymphocytes will assess alterations in normal IL-2 and IL-2R expression. These studies will use both a molecular and cellular approach to find optimal sensitivity and a therapeutic """"""""window"""""""" for effective suppression. Lymphocyte phenotypes, and IL-2R expression within the granuloma will be evaluated by both flow cytometry and immunoperoxidase allowing a precise quantitation of cell number and spatial relationships of lymphocytes. Granuloma development will be determined following treatment with exogenous human recombinant IL-2 and a monoclonal antibody directed against the IL-2R by: a) morphometric analysis of size, b) determination of lymphocyte populations, c) IL-2 production and, d) IL-2R expression. Using the techniques of molecular biology, flow cytometry, immunoperoxidase and quantitative morphometry, the central roles of IL-2 and IL-2R in regulating pulmonary granulomatous inflammation will be carefully dissected.
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