Suppression of Anaphylactic Reactions in Guinea Pigs by Previous Treatment with Ragweed Aerosol

Abstract

Guinea pigs subjected to intranasal dusting with ragweed (RW) pollen or intranasal instillation of RW extract (RWE) showed anaphylactic reactions when subjected to RW extract aerosol (RWEA). These animals, however, did not respond to an aerosol of RW whole pollen. Animals which received the RWEA treatment prior to nasal dusting with RW pollen showed no subsequent anaphylactic reactions when exposed to RWEA. Both the aerosol-sensitive and the aerosol-nonresponsive animals exhibited high titers of homocytotropic antibodies to RWE. In addition, the aerosol-nonresponsive animals also had precipitating antibodies of IgG type. The state of nonresponsiveness did not appear to be due to the precipitating antibodies, since this condition could not be passively transferred by sera and blocking antibody activity was not demonstrable.

Physiological and Immunological Effects of Chronic Antigen Exposure in Immunized Guinea Pigs

“…Possible immunologic expla nations for this phenomenon include a decrease in homocytotropic antibody levels, the presence of a blocking antibody, decreased antibody receptors on mast cells, or suppressor cells or factors acting to pre vent mast cell mediator release. Many other investiga tors have attempted to correlate PCA titers with the level of anaphylactic responsiveness [4,6,7,19,20]. In general, these studies have failed to show a tight correlation between antibody levels and degree of re sponsiveness, similar to our present study in which the animals that developed tolerance to the antigen did not show a decrease in PCA titers.…”

“…Similar observations have been made when sensitization was attained by various methods including i.p. injection of antigen [7,8,18], oral ad ministration of antigen [4], passive sensitization [5], and chronic aerosol challenge [6,8]. Depending on the schedule of antigen exposures followed, the gui nea pigs began to show signs of diminished response as early as the 2nd week [5,8] or as late as the 4th week [3] of antigen exposure.…”

Enhancement of IgE Antibody Production by Ovalbumin Aerosol in Mice

“…[13] and Blanchard el al. [ 14], The duration and frequency of exposure to aeroso lized antigensbytheseauthorsweredifferent from what wasusedbyus. Incontrasttosingleshort-term preexpo sure, repeated long-term preexposures might exert a suppression of IgE antibody formation.…”

Repeated Antigen Inhalation-Induced Reproducible Early and Late Asthma in Guinea Pigs.

“…By repeating sensitization /challenge, no decrease in the level of either r1 or IgE antibody was recognized. (18)(19)(20)(21)(22)(23). If such a model with experimental asthma with chronicity could be made, it would contribute much to asthma research.…”

“…On the other hand, it is worthwhile to establish a semichronic or chronic experimental model of allergic bronchial asthma for detailed analysis of the disease and the evaluation of the drugs that have been used as a remedy. However, this model has been little studied because repeated antigen challenge causes the pulmonary organ of guinea pigs to become unresponsive (18)(19)(20)(21)(22)(23).…”