chapter  5
30 Pages

Interleukin-6

ByCarl D. Richards, Ronald W. Scamurra, Michael P. Murtaugh

Cytokines are a group of intercellular signaling molecules that are released by host cells and act in a nonenzymatic, hormone-like fashion to regulate single or multiple aspects of cell function. Many cytokines act in a variety of tissues, and multiple cell types have been shown to produce a particular cytokine. Interleukin-6 (IL-6) falls into this category of pleiotropic molecules with significant roles in inflammation, hematopoiesis, lymphocyte activation, and differentiation. IL-6 is present in physiologically relevant concentrations in body fluids, and experiments in animal models have shown that exogenously administered IL-6 has significant biological effects. These data have been generated relatively recently over the past few years and confirm the importance of IL-6 in vivo. Intense investigation has resulted in the molecular cloning of the IL-6 cDNA, gene, and receptor complexes, and insight into the molecular mechanisms by which this molecule stimulates cells. Some data have been generated examining in vivo functions in rodent models of inflammation, however less information is available on IL-6 in food animals. Most of the data summarized here will reflect the work completed in human, rodent, and swine systems.154