マクロファージのＭＩＦとビタミンＥ

Abstract

Macrophages play a key role in inflammatory reactions and immune reactions through releasing a variety of inflammatory mediators, such as prostanoids, superox-ide anions, and monokines. Macrophage migration inhibitory factor (MIF), one of the monokines, was originally discovered as a T lymphocyte-derived cytokine inhibiting migration of macrophages out of capillary tubes. Recently, Northern blot analysis indicated that the MIF mRNA was expressed in a wide variety of organs, including the brain, kidney, and liver. From the available data on MIF, it is considered that the protein is associated not only with immune responses but also with cell growth and differentiation during wound repair and carcinogenesis. On the other hand, vitamin E is recently noticed to play an important role as an antioxidant and moreover in immune responses, including protection against infections and carcino-gens beyond antioxidant functions. In order to clarify the possible role of vitamin E on the modulation of macrophages, we investigated the effect of vitamin E on MIF production in macrophages as stimulated with various agents. Intraperitoneal injec-tions of vitamin E (5 mg per rat) for 6 successive days resulted in a significant increase of α-tocopherol content in peritoneal macrophages. Vitamin E-treated rats showed 478.3±90.7 ng/l06cells, whereas control rats showed 1.5±0.5 ng/106cells. MIF secretion from control macrophages increased in response to calcium ionophore A23187 and LPS. However, increase of MIF was significantly suppressed in vitamin E-treated macrophages compared with that of control macrophages. From these results, it is suggested that vitamin E plays a pivotal role within the cytokine network in various pathophysiological states.