Distribution of cells binding anti-IgE in the trachea and in the thoracic lymph nodes of ovalbumin-sensitized rats.

We investigated in the present study the distribution of anti-IgE binding cells in the trachea and in the thoracic lymph nodes of ovalbumin (OA)-sensitized rats. Sensitization of the airways was induced through a single intratracheal injection of the antigen, and was controlled by recording in vitro the antigen-induced contraction of the tracheal muscle: 12 of 15 (80%) OA-injected rats had a demonstrable status of tracheal sensitization. An immunohistochemical method was used for the localization of the anti-IgE binding cells in cryostat and in Carnoy fixed tissue sections. Virtually no cell was found to bind anti-IgE in the tracheas or in the thoracic lymph nodes from control animals. Conversely, we found in OA-sensitized rats that: 1) numerous IgE plasma cells appeared in the medullary cords of the lymph nodes (not in the trachea); 2) in tracheal sections, IgE concentrated in the cytoplasm of subepithelial mast cells and of nonciliated rounded epithelial cells (possibly the so-called globule leukocytes), but few if any mast cells of the connective tissue bound the anti-IgE conjugates.