The mechanisms of bronchospasm in experimental microbial sensitization. I. Immunological stage.

Immune mechanisms of smooth muscle spastic bronchial reactions were reproduced and studied in isolated guinea pig lungs and found to develop type I, III and IV allergic reactions at sensitization to brucella and staphylococcus. Type I reactions were reproduced in animal lungs with immediate hypersensitivity to soluble microbial antigens. Type III reactions were obtained by transfusion of soluble immune complexes containing microbial antigens into isolated lungs Bronchospastic reactions arose only in the presence of the complement. Antibodies responsible for bronchospasm belonged to the IgG class. Type IV reactions were produced in vitro using supernatants obtained by incubation of lymphoid cells isolated from animals with delayed hypersensitivity with homologic microbial antigens. The supernatants possessed bronchospastic action.