Oxidative responses in ferret macrophages

Although the basic function of T and B lymphocytes in ferrets has been know n for some time, the function of mononuclear phagocytes has not been descri bed in this species. The present study has characterised basic oxidative re sponses in ferret macrophages, and has investigated the effects of endogeno us and exogenous modulators of macrophage function on oxidative capacity in vitro. Macrophages derived from the blood or lungs of ferrets were shown c apable of generating the reactive oxygen intermediate (ROI) molecules super oxide and hydrogen peroxide, and secreting a lysosomal enzyme (acid phospha tase), in response to appropriate stimuli. A T cell supernatant (derived fr om mitogen-stimulated peripheral blood lymphocytes) was able to activate bo th blood- and lung-derived macrophages for enhanced ROI production, while s pecific ROI inhibitors (superoxide dismutase and catalase) were able to par tially ablate ROI activity. The accumulation of nitrite in culture supernat ants, as an indicator for the production of reactive nitrogen intermediates , could not be demonstrated by ferret macrophages derived from either tissu e source. In contrast to the enhancing effects of TCS on the oxidative func tion of blood-derived macrophages, exposure to bacterial LPS caused marked suppression of ROI and lysosomal enzyme production by these cells. Finally, the generation of superoxide anion, following phagocytosis of live or heat -killed Mycobacterium bovis or zymosan, indicated that ROI production in re sponse to phagocytic stimulation was relatively weak in ferret blood-derive d macrophages. These results are discussed in relation to the study of immu ne function in a novel species, and with particular reference to research i nto tuberculosis (Tb), since ferrets are important wildlife vectors of bovi ne Tb in New Zealand. (C)O 1999 Elsevier Science B.V. All rights reserved.