Class II MHC molecules and monocytes/macrophages in the respiratory system of conventional, germ-free and interferon-gamma-treated rats.
The localization of I-A-like class II major histocompatibility complex (MHC) molecules and cells of the monocyte/macrophage lineage was studied immunohistologically in the trachea and lungs of conventional, specified pathogen-free (SPF) and germ-free rats. In the three groups of animals I-A-like class II MHC molecules occurred in epithelia of the bronchus-associated lymphatic tissue (BALT), in B lymphocytes, in dendritic-shaped and elongated interstitial cells and in type II pneumocytes. Conventional and SPF rats were distinguished from germ-free animals only by the larger number of class II MHC-positive respiratory epithelial cells in the lower trachea and main bronchi. The distribution of monocytes/macrophages (ED1-positive cells) did not differ between the groups. After systemic treatment of SPF rats with interferon-gamma class II MHC molecules were newly induced in all respiratory epithelia and in the endothelium of large vessels. In addition, interferon-gamma sometimes led to pulmonary infiltration and caused class II-positive activated monocytes to accumulate in medium-sized pulmonary vessels and in alveolar capillaries. It is concluded that the microbial status does not qualitatively alter the distribution of class II MHC molecules and monocytes/macrophages in rat respiratory organs. Interferon-gamma can, however, provoke profound changes.
Steiniger
B
B
Centre of Anatomy, Hannover Medical School, Germany.
Sickel
E
E
D000818:Animals; D000911:Antibodies, Monoclonal; D005856:Germ-Free Life / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D007124:Immunoenzyme Techniques; D007262:Infusions, Intravenous; D007371:Interferon-gamma / Q000008:administration & dosage*; D008168:Lung / Q000187:drug effects / Q000276:immunology*; D008264:Macrophages / Q000166:cytology / Q000276:immunology*; D008297:Male; D009000:Monocytes / Q000166:cytology / Q000276:immunology*; D051381:Rats; D011917:Rats, Inbred Lew; D011994:Recombinant Proteins; D014132:Trachea / Q000187:drug effects / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000949:Histocompatibility Antigens Class II; D011994:Recombinant Proteins; D007371:Interferon-gamma