IgE antibody suppression following aerosol exposure to antigens

Exposure of mice to aerosolized antigens induced a low level IgG1 response but not detectable IgE antibodies. Subsequent intraperitoneal immunization of these mice demonstrated immunoglobulin class-specific IgE suppression. Low concentrations of nebulized antigen induced IgE suppression which was antigen specific and persisted on subsequent secondary and tertiary injections. Although a single aerosolized antigen exposure significantly decreased the IgE response, maximal suppression was observed when the mice were exposed to nebulized antigen once weekly for at least 6 weeks. The suppression was not observed until 3 weeks following nebulizer exposure. Mice exposed once weekly to nebulized antigen for 6 weeks and then rested for 2 months before intraperitoneal immunization still demonstrated suppression. However, animals first immunized intraperitoneally and then exposed to nebulized antigen produced normal secondary IgE and IgG1 responses. These results suggest that antigen exposure by aerosol may profoundly alter the IgE response.