Abstract
Repeated challenge of high-IgE-responder BN rats with an antigen aerosol in the absence of adjuvant, elicited both specific IgE and IgG responses in serum. Employing the recently developed ELISA plaque assay to detect individual IgE and IgG secreting cells, the lymph nodes draining the lower respiratory tract were pinpointed as the site for initiation of this response, and the sole location of specific IgE-secreting cells. Subsequent analysis of the tissue distribution of total IgE-secreting cells revealed that ≥50% were located in the lymph nodes draining the upper and lower respiratory tracts.