Erythrocyte rosette forming activity of macrophage

Erythrocyte rosette forming activities of the rat lung macrophage, peritoneal macrophage, Kupffer cells and expressed splenic cells were studied. The erythrocytes employed were fresh human red blood cell (RBC), fresh sheep RBC (SRBC), and tanned SRBC coated with bovine albumin or with bovine gamma-globulin. The macrophages were mixed with RBC at a ratio of 1 to 100 or 200 in gelatin veronal buffer or phosphate buffered saline. The experiments were carried out at 4 degrees C. No autologous serum nor anti-RBC serum was added to the experimental system. 10 to 20 per cent of the lung macrophages formed rosette and their entire surfaces were covered with RBC. The peritoneal macrophage and Kupffer cells were also capable of forming rosette with fresh SRBC as well as with SRBC coated with bovine albumin or with bovine gamma-globulin. Examinations for cell surface immunoglobulin of alveolar macrophage, peritoneal macrophage, Kupffer cells and splenic cells revealed that alveolar and peritoneal macrophages apparently possessed surface gamma-globulin and that almost all of these macrophages possessed surface immuno-globulin. In order to examine the effect of different natures of SRBC on in vivo phagocytosis, rats were immunized with SRBC by injecting various SRBC into the femoral or the portal vein and the hemagglutinin titer was studied. The maximum hemagglutinin titer was observed in the rat injected with fresh SRBC into the femoral vein and the minimum hemagglutinin titer was observed in the splenectomized rat injected with fresh SRBC and in the rat injected with SRBC coated with albumin or gamma-globulin into the femoral or portal vein. Immunological role of Kupffer cells was discussed.