Antigen-induced bronchial anaphylaxis in actively sensitized SD rats. Effects of immunization and provocation doses of antigen and of pretreatment with DSCG, theophylline, terbutaline and a new anti-allergic xanthine derivative, D4026.

Bronchial anaphylactic reactions, estimated as increase in intratracheal pressure, were precipitated by intravenous injections of antigen into actively sensitized SD rats. The degree of bronchial reactivity was found to depend on both the challenge dose and the immunization dose of antigen; therefore the course of the capacity to respond was recorded as a function of these variables. The degree of the bronchial anaphylactic response could be reduced by pretreatment with disodium cromoglycate, terbutaline or a new anti-allergic xanthine derivative, D 4026, in some groups of animals. The efficacy of each agent was found to depend on the dose of antigen used for sensitization and for provocation of the bronchial reaction rather than on the strength of the response. Taken together, the data suggest that more than one type of homocytotropic antibody mediates bronchial anaphylactic reactivity in the SD rat.