MODEL OF ALLERGIC BRONCHOCONSTRICTION IN THE GUINEA-PIG .2. RECURRENT REACTIONS IN INDIVIDUAL ANIMALS

Recurrent allergic bronchoconstriction was produced in passively sensitized guinea pigs utilizing either a 3-day or a 5-day weekly cycle of reactions over a 4-week period. This was accomplished by administering a different homologous antiserum on as many days per week as responses were to be elicited with aerosolized antigen in the subsequent week. Following each challenge the guinea pigs were reinjected with another dose of the same antiserum and accordingly were primed to react again on the same day of the next week. The frequency of a positive challenge was higher in the 3-day compared with the 5-day weekly cycle. There was a systematic decrease in reactivity over the course of each week and from week to week. This could not be explained by a change in responsiveness due to an effect of age, by a decrease in the potency of the antigens or antisera, by a depletion of lung histamine stores, by a reduced capacity of the lung tissue to undergo passive sensitization or by a cross-reactivity between antigen-antibody systems resulting in desensitization. Nevertheless, recurrent reactions were successfully elicited in a substantial proportion of the animals tested in the 3-day weekly cycle. © 1979.