This is a program of three distinct but interrelated projects: Project I concern the maintenance of a colony of monkeys which are a relevant model of extrinsic asthma in man. The airway response to various external agents including antigens or other immunologic reactants and pharmacologic agonists or antagonists will be evaluated by several parameters including those obtainable by whole body plethysmography. Some of these studies will also be done in antigen sensitive dogs. Project II investigates the specific mediator releasing cells found in the bronchial lumen of animals and man. Cells obtained by lavage at sensitive animals or patients under diagnosis will be studied with respect to their ultrastructure and its changes during the release reaction. The effect of cromolyn and other inhibitors of this process will be examined. Correlation of the structural and biologic changes will be made. Project III is an investigation of pulmonary function in human asthma and similar diseases. The temporal relationship between pressure-volume changes and symptoms during challenge and recovery will be studied. The contribution of cholinergic mechanisms in bronchospasm of allergic but non-asthmatic patients will be assessed. The effect of immunotherapy on bronchial sensitivity of patients will be evaluated.