title: Changes occurring in the epithelium covering the bronchus-associated lymphoid tissue of rats after intratracheal challenge with horseradish peroxidase.
abstract: Changes occurring in the epithelium covering bronchus-associated lymphoid tissue (BALT) in the rat after several intratracheal administrations of horseradish peroxidase (HRP) were studied using morphological and ultrastructural methods. The epithelium is invaded by W3/25-positive (T-helper) lymphocytes, the BALT epithelial cells become Ia-positive and develop microvilli; there is an apparent loss of cilia. The number of non-ciliated cells in stimulated BALT increases. The non-ciliated cells can be subdivided into two cell types, one with electron-dense cytoplasm and cytoplasmic granules and the other without granules. The electron-density of the latter cell type is intermediate between that of the ciliated cells and that of the granule-containing non-ciliated cells. The granule-containing cell types may be responsible for the uptake of antigens, while the other non-ciliated cell may be involved in the production of the secretory component and the passage of secretory IgA.
mesh_terms: D000818:Animals; D000941:Antigens; D001980:Bronchi / Q000166:cytology / Q000276:immunology* / Q000648:ultrastructure; D004847:Epithelial Cells; D004848:Epithelium / Q000276:immunology / Q000648:ultrastructure; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D006735:Horseradish Peroxidase; D007124:Immunoenzyme Techniques; D007070:Immunoglobulin A / Q000032:analysis; D008214:Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D010544:Peroxidases; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D000941:Antigens; D000949:Histocompatibility Antigens Class II; D007070:Immunoglobulin A; D006735:Horseradish Peroxidase; D010544:Peroxidases