1. Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892.
2. Institut Gustave Roussy, Centre National de la Recherche Scientifique Unité Associée 1301, 94805 Villejuif Cedex, France.
3. Transgene SA, 67082 Strasbourg, France.