[Bronchoalveolar lavage in the pig--comparison of normal, pathogen-free and pneumonic animals]

The cells found in the BAL fluid of the pig were characterised morphologically and immunocytologically with monoclonal antibodies. The percentage of macrophages was found to be 80%, and that of lymphocytes, 20%. Granulocytes are characteristic when pneumonia is presenting. B-cells are rarely observed in germ-free animals, account for 5-8% in the normal animal, and are elevated in pneumonia. The percentage of T-helper cells is not changed by germ-free breeding or in the presence of pneumonia. In germ-free animals, the percentage of T-suppressor cells is reduced, but remains unchanged in pneumonia.