ANTIBODY-MEDIATED HEPATOTOXICITY OF ETHANOL

乙醇的主要代谢物乙醛已被证明是 与蛋白质和磷脂上的氨基反应生成二次 N-乙胺加合物。在蛋白质加合物形成的情况下 乙醇的代谢，这些胺已被证明是新的抗原 并产生免疫反应。之前的研究表明， 血清中存在与结合的抗体之间的相关性 这些加合物和酒精相关的肝毒性。我们最近展示了 在兔体内产生的一些多克隆抗体可以对抗 乙醛加合物与人工合成的蛋白质加合物的交叉反应 乙醛-磷脂酰乙醇胺加合物(N-乙基-PE)。如果 N-乙基-PE加合物在体内酒精代谢过程中形成，然后 交叉反应抗体与暴露在细胞表面的这些加合物结合 肝细胞表面可能与酒精相关 肝脏毒性。这项提案的目的是确定是否 乙醛加合物的磷脂出现在表面 酒精暴露的肝细胞及其抗体结合的结果 在肝细胞裂解中作为中性粒细胞激活或 互补性。描述了一系列步骤，这些步骤将确定 在体内形成磷脂的乙醛加合物，测量 抗体与肝细胞的结合 N-乙基磷脂酰乙醇胺在其表面的应用 流式细胞术，并测量免疫介导的细胞毒性 中性粒细胞或补体与抗体结合所致 肝细胞表面。这些研究可能在两个方面具有重要意义：第一， 乙醛-磷脂加合物的外观测量可 在现有的检测中增加一个重要的附加成分，用于标记 酒精暴露。第二，由提供的额外的半抗原表位 肝细胞表面的乙醛-磷脂加合物可能是 中性粒细胞结合的贡献因素或补充结果 在免疫介导的肝毒性中。

The principle metabolite of ethanol, acetaldehyde, has been shown to react with amino groups on proteins and phospholipids to yield secondary N-ethylamine adducts. In the case of protein adducts formed during metabolism of ethanol, these amines have been shown to act as neoantigens and generate an immune response. Previous studies have shown a correlation between the presence in the serum of antibodies that bind to these adducts and alcohol-related hepatotoxicity. We have recently shown that some of the polyclonal IgG antibodies raised in rabbits against protein adducts of acetaldehyde cross-react with synthetic acetaldehyde-phosphatidylethanolamine adducts (N-ethyl-PE). If N-ethyl-PE adducts are formed in vivo during metabolism of alcohol, then binding of cross-reactive antibodies to these adducts exposed on the surface of hepatocytes could contribute to alcohol-related hepatotoxicity. The aims of this proposal are to determine if acetaldehyde adducts of phospholipids appear on the surface of alcohol-exposed hepatocytes and if binding of antibodies to them results in lysis of hepatocytes as a consequence of activation of neutrophils or complement. A sequence of steps is described that will determine whether acetaldehyde adducts of phospholipids are formed in vivo, measure the binding of antibodies to hepatocytes that have N-ethyl-phosphatidylethanolamine incorporated into their surface using flow cytometry, and measure the immune-mediated cytotoxicity that could result from binding of neutrophils or complement to antibodies on the hepatocyte surface. These studies may be significant in two ways: First, measurement of the appearance of acetaldehyde-phospholipid adducts may add an important additional component to existing assays for markers of alcohol exposure. Second, the additional haptenic epitopes provided by acetaldehyde-phospholipid adducts on the hepatocyte surface may be a contributing factor in binding of neutrophils or complement that results in immune-mediated hepatotoxicity.