title: Distribution of Ia antigens and T lymphocyte subpopulations in rat lungs.
abstract: In order to examine the mechanism of specific immunity in the lung, the distribution of Ia antigens and T lymphocyte populations was determined using immunoperoxidase-staining of cryostat sections of lungs from specific pathogen-free rats. BALT was found to be divided into three regions of lymphoid tissue. The central region was primarily composed of B cells, and was surrounded by a peripheral region of T cells (MRC OX-19+) which included both T helper (W3/25+) and T suppressor/cytotoxic (MRC OX-8+) cells. The subepithelial region contained a dense network of W3/25+, non-T cells. A majority of BALT cells, including the lymphoepithelial cells, were Ia+. The alveolar walls were found to contain numerous Ia+ dendritic-shaped cells. Alveolar macrophages found in sections, as well as those collected using bronchoalveolar lavage, were Ia- and W3/25-. Mechanisms for the induction of immunity within both BALT and the alveolar region are proposed.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D001402:B-Lymphocytes / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000032:analysis*; D007124:Immunoenzyme Techniques; D008168:Lung / Q000166:cytology / Q000276:immunology*; D008297:Male; D011650:Pulmonary Alveoli / Q000276:immunology; D051381:Rats; D011916:Rats, Inbred F344; D013601:T-Lymphocytes / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000949:Histocompatibility Antigens Class II