AEROSOLIZED ANTIGEN DOSE-RESPONSE STUDIES IN ASTHMATIC MONKEYS

Abstract

Rhesus monkeys which had consistent respiratory responses to a standard (single dose) aerosolized concentration of A [Ascaris antigen] were studied. Beginning at lower concentrations of A which did not produce an airway response, 4-fold increases in concentrations of A were aerosolized until an airway response occurred. Compared with the single-dose SAC [standard Ascaris challenge] after the TAC [threshold Ascaris challenge], some consistently reactive animals did not respond to the SAC, the maximal concentration of A used for testing. The TAC may result in an acute form of airway desensitization. Animals vary in the threshold concentrations of A required to produce an airway response. A repeat challenge with the threshold antigen concentration during the same experiment resulted in a 2nd response generally greater than the initial response at the same concentration. When the SAC system was similarly evaluated by repeat challenges with the same A concentration, the 2nd response was generally less than the 1st. Different methods for evaluation of pharmacologic inhibitors of Ig[immunoglobulin]E-mediated airway responses may be developed from this rhesus model of asthma.