Transfection of CD14 into 70Z/3 cells dramatically enhances the sensitivity to complexes of lipopolysaccharide (LPS) and LPS binding protein.
Transfection of CD14 into 70Z/3 cells dramatically enhances the sensitivity to complexes of lipopolysaccharide (LPS) and LPS binding protein.
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DOI：
10.1084/jem.175.6.1697
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发表时间：
1992-06-01
期刊：
影响因子：
--
通讯作者：
Ulevitch RJ
中科院分区：
文献类型：
--
作者：
Lee JD;Kato K;Tobias PS;Kirkland TN;Ulevitch RJ
细菌内毒素(脂多糖[LPS])可引起人类和实验动物的致命性休克。休克是由内毒素直接刺激单核细胞来源的细胞(单核/巨噬细胞[MO])释放的细胞因子介导的。最近的研究支持这样一个概念，即血浆蛋白--内毒素结合蛋白(LBP)在控制MO对内毒素的反应中起着重要作用。具体地说，已有证据表明，存在于MO中的一种膜蛋白CD14是脂多糖和血浆蛋白脂多糖结合蛋白(LBP)复合体的受体。在这一功能中，CD14介导与LBP调理的含脂多糖颗粒的黏附，并在调节脂多糖与LBP复合体诱导的细胞因子产生中发挥重要作用。CD14-小鼠Pre-B细胞系70z/3通过合成kappa轻链和随后的表面IgM表达来应答内毒素。为了更好地了解CD14在控制细胞对内毒素反应中的作用，我们研究了CD14基因转染70z/3细胞对内毒素应答的影响。本文报道了将人或兔CD14基因导入70z/3细胞，膜上表达糖基-磷脂酰肌醇锚定的CD14。当脂多糖与LBP复合时，携带CD14的70z/3细胞与内毒素的结合量明显高于亲本细胞或单纯载体转染组。值得注意的是，CD14的表达将刺激表面IgM表达所需的脂多糖量降低了10,000倍，比较了携带CD14的亲本细胞和携带CD14的70z/3细胞的脂多糖剂量-反应曲线。相比之下，携带CD14的70z/3细胞和亲本70z/3细胞系(CD14-)对干扰素伽马的反应是无法区分的。脂多糖对亲本细胞和携带CD14的70z/3细胞的刺激可导致核因子-kB的激活。这些数据支持这一观点，即表达CD14的细胞中的内毒素受体可能是一种包含CD14和膜蛋白(S)的多蛋白复合体，这些蛋白是不同类型的内毒素反应细胞所共有的。
Bacterial endotoxin (lipopolysaccharide [LPS]) causes fatal shock in humans and experimental animals. The shock is mediated by cytokines released by direct LPS stimulation of cells of monocytic origin (monocyte/macrophage [MO]). Recent studies have supported the concept that the plasma protein, LPS binding protein (LBP), plays an important role in controlling MO responses to LPS. Specifically, evidence has been presented to suggest that CD14, a membrane protein present in MO, serves as a receptor for complexes of LPS and the plasma protein LPS binding protein (LBP). In this function CD14 mediates attachment of LPS- bearing particles opsonized with LBP and appears to play an important role in regulating cytokine production induced by complexes of LPS and LBP. The CD14-, murine pre-B cell line 70Z/3 responds to LPS by synthesis of kappa light chains and consequent expression of surface IgM. To better understand the role of CD14 in controlling cellular responses to LPS, we investigated the effect of transfection of CD14 into 70Z/3 cells on LPS responsiveness. We report here that transfection of human or rabbit CD14 cDNA into 70Z/3 cells results in membrane expression of a glycosyl-phosphatidylinositol-anchored CD14. When LPS is complexed with LBP, CD14-bearing 70Z/3 cells bind more LPS than do the parental or 70Z/3 cells transfected with vector only. Remarkably, the expression of CD14 lowers the amount of LPS required to stimulate surface IgM expression by up to 10,000-fold when LPS dose- response curves in the CD14-, parental and CD14-bearing, transfected 70Z/3 cells are compared. In contrast, the response of CD14-bearing 70Z/3 cells and the parental 70Z/3 cell line (CD14-) to interferon gamma is indistinguishable. LPS stimulation of the parental and CD14- bearing 70Z/3 cells results in activation of NF-kB. These data provide evidence to support the concept that the LPS receptor in cells that constitutively express CD14 may be a multiprotein complex containing CD14 and membrane protein(s) common to a diverse group of LPS- responsive cells.