Since the isolation of the cDNA of macrophage migration inhibitory factor (MIF), a number of novel biological properties of this cytokine have been discovered. The primary amino acid sequence of MIF is well conserved among a wide range of species. MIF is constitutively expressed not only in T cells, but also in a variety of other cells, including macrophages and epithelial cells of various organs. With regard to its biological function, MIF plays an important role as a proinflammatory cytokine, initiating production of other inflammatory cytokines, and as an anterior pituitary-derived hormone, potentiating lethal endotoxemia. In particular, it should be emphasized that this protein has the potential to override the glucocorticoid-mediated suppression of inflammatory and immune responses. Judging from an array ofin vivostudies, it is clear that anti-MIF antibodies efficiently suppress endotoxin-and exotoxin-induced inflammation and immune responses as well as tumor growth and angiogenesis. This review presents the latest findings on the roles of MIF in inflammatory and immune responses, as well as in cell growth and differentiation.
