MACROPHAGE FUNCTION IN DEER

Macrophage inflammatory and immune functions were characterised in red deer (Cervus elaphus), for use as a model for natural infection with bovine tuberculosis. Highly enriched populations of deer macrophages w ere obtained from 14 day cultures of plastic-adherent peripheral blood mononuclear cells. Cervine macrophages produced superoxide anion in r esponse to respiratory burst stimuli (serum-opsonised zymosan and phor bol myristic acetate), but nitric oxide production could not be detect ed under the conditions tested. The lysosomal enzymes acid phosphatase and lysozyme were detected at the intracellular and extracellular lev el. Stimulation with bacterial lipopolysaccharide extract (Escherichia coli LPS) enhanced the production of superoxide and acid phosphatase, with a peak increase in activity observed after 2 h. Production of in terleukin 1 (IL-1) and tumour necrosis factor (TNF), determined using cytokine-sensitive cell lines and mRNA analysis (Northern blotting), i ndicated maximal secretion of both cytokines after 24 h stimulation wi th LPS, preceded by a peak in message accumulation at 2-6 h post-stimu lation. Cervine macrophages stimulated proliferative responses in T ce ll-enriched lymphocyte populations derived from the peripheral blood o f autologous animals that had been primed to mycobacterial antigens (M ycobacterium bovis Bacille Calmette-Guerin, BCG). Macrophages were abl e to stimulate responses after pulsing with particulate (BCG) or solub le (purified protein derivative) mycobacterial antigens. These results indicate that macrophage inflammatory and immune responses in red dee r are similar to those in other mammalian species, and that macrophage s may play an important role in resistance to mycobacterial infection.