Bronchospasm mechanisms in experimental microbial sensitization. II. Pathochemical stage.

The pathochemical mechanisms of bronchospasm have been studied using various type of experimental allergies to microbial antigens. It was established that in guinea pigs with type I allergies isolated lung bronchospasm was mediated by histamine and SRS-A. Bronchial response to immune complexes type III were produced by the activation of complement with subsequent degranulation of mast cells and histamine release. Type IV hypersensitivity (lymphokine-mediated bronchospasm) was manifested without histamine, acetylcholine and mast cell involvement. The response to lymphokine was blocked by atropine. The spasmogenic y lymphokines are large molecular thermolabile substances.