Rapid Publication Human Eosinophil Major Basic Protein Induces Airway Constriction and Airway Hyperresponsiveness in Primates

We have examined the effects of direct intratracheal instilla-tion of purified eosinophil granule proteins on pulmonary func-tion and airway responsiveness in primates. The results of this study show for the first time that installation of major basic protein (MBP) directly into the trachea of primates results in a significant and dose-related increase in airway responsiveness to inhaled methacholine. Furthermore, MBP and eosinophil peroxidase (EPO) induce a transient bronchoconstriction imme-diately after instillation that resolves by 1 h postinstillation. In constrast, instillation of other eosinophil granule proteins had no effect on airway responsiveness or pulmonary function. These data indicate a direct role of the eosinophil in the patho-genesis of airway hyperresponsiveness. We suggest that the MBP of human eosinophils has an effector role in the pathogenesis ofairway hyperresponsiveness which may involve active interaction with resident airway tissue cells. MBP may also mediate altered lung function in various inflammatory lung diseases associated with pulmonary eosino-philia. (J. Clin. Invest. 1991. 87:1470-1473.) Key words: eo-sinophil granule proteins * airway hyperreactivity- bronchocon-striction * monkeys * asthm