The role of macrophage migration inhibitory factor in endotoxin shock

巨噬细胞迁移抑制因子（Macrophage migration inhibitory factor， MIF）是首次在凝集素活化的T淋巴细胞中发现的淋巴因子。它最初是通过其在体外阻止巨噬细胞从毛细血管中迁移的能力而确定的。首先从t淋巴细胞中克隆人MIF cDNA，结果表明该蛋白由114个氨基酸残基组成。长期以来，人们一直认为MIF只在活化的t淋巴细胞中表达；然而，最近的一份报告表明巨噬细胞是MIF的另一个主要来源。MIF的许多新的生物学特性已经被发现。MIF是垂体前叶细胞在响应脂多糖刺激时释放的主要分泌蛋白，被认为在内毒素血症中起核心作用。在MIF研究过程中，我们克隆了大鼠MIF cDNA，并报道了其理化性质。此外，我们成功地结晶了人和大鼠MIF，并在2.2 *分辨率下阐明了大鼠MIF的三级结构。此外，我们还在人类皮肤和角膜中发现了MIF的表达，这表明MIF的表达并不局限于T淋巴细胞和巨噬细胞。

Macrophage migration inhibitory factor (MIF) was the first lymphokine discovered in lectin-activated T lymphocytes. It was originally identified by its ability to prevent the migration of macrophages out of a capillary tube in vitro. Human MIF cDNA was first cloned from T-lymphocytes, which revealed that the protein consists of 114 amino acid residues. MIF has long been considered to be expressed exclusively in activated T-lymphocytes ; however, a recent report indicated that macrophages are another major source of MIF.Various novel biological properties of MIF have been discovered. MIF is the major secretory protein released by anterior pituitary cells in response to lipopolysaccharide stimulation and is considered to play a central role in endotoxemia. During the course of our MIF study, we cloned rat MIF cDNA,and reported its physicochemical properties. We moreover succeeded in the crystallization of both human and rat MIFs, and elucidated the tertiary structure of rat MIF at 2.2 * resolution. Furthermore, we identified the expression of MIF in human skin and cornea, which indicated that expression of MIF was not limited to T lymphocytes and macrophages.