AVIAN MACROPHAGE METABOLISM

This review considers the role of avian macrophages as a source of imm une effector and immunoregulatory metabolites. Although considerable a ttention has been given to the importance of leukocytic cytokines, par ticularly the monokines such as interleukin-1 (IL-1), interleukin-6 (I L-6), tumor necrosis factor-alpha (TNF-alpha), and transforming growth factor-beta (TGF-beta), metabolites produced by macrophages appear to be of equal importance in determining the progression of immune respo nses. The three metabolite categories that have received the greatest attention are the reactive oxygen species (ROS), the reactive nitrogen intermediates (RNI), and the eicosanoids. Additionally, the xenobioti c metabolites produced via cytochrome P450 activity mediate some immun e-environmental interactions. Each of these four metabolite categories is subject to different requirements for metabolite production, and e ach has distinct effector functions. An understanding of macrophage me tabolite regulation could allow improvements in avian health managemen t and production via the effective control of metabolite production. T he present review considers prior and recent information on the produc tion of the metabolites by avian macrophages. Additionally, the potent ial ramifications of metabolite production and regulation are discusse d.