TRANSFUSION OF ANTIGENICALLY MODIFIED ERYTHROCYTES

红细胞（RBC）输注是血液透析的重要组成部分。 治疗一些急性和慢性疾病。 在大多数 急性损伤，简单的红细胞分型（ABO/Rh）足以识别 合适的捐助者。 然而，问题经常出现在 接受慢性输血的个体，通常是少数民族（例如， 镰状细胞性贫血和地中海贫血）。事实上，简单的血型鉴定 通常不足以确定适当的匹配， 个体对次要RBC抗原产生输血反应。 这 对次要红细胞抗原的反应性使其几乎不可能 确定合适的献血者。 因此，希望 人工伪装细胞抗原决定簇， 异源供体红细胞存活和防止同种异体致敏 正在发生。 到目前为止，这是不可能的。 但此前的 研究表明聚（乙烯）的共价键 乙二醇）[PEG]与蛋白质的结合， 防止/减少蛋白质抗原性。 同样，关于 脂质体已经证明在脂质体中包含PEG缀合的脂质， 该膜还延长了体内循环。 基于这些 研究结果，这是这个建议的假设，共价键 非免疫原性长链聚合物（例如，PEG或PEG 衍生物）对完整红细胞的作用可以有效地掩盖抗原性 决定簇，降低RBC免疫原性，和 减少/预防由于以下差异引起的输血反应： 供体和受体RBC表型。 因此，具体目标 该建议是为了确定：1）哪些化合物有效地掩蔽RBC 抗原性，并检查分子量和几何形状 PEG/PEG-衍生物的（线性与支化）影响细胞内的 免疫原性; 2）结构、功能和代谢后果 RBC与PEG/PEG衍生物的衍生化;以及3） RBC衍生化对体外和体内存活的影响。 中概述的 该提案，使用该技术的初步研究表明， 衍生的人RBC在形态上是正常的， 显著降低：ABO/次要RBC抗原性，免疫原性， 抗RBC抗体的结合和吞噬作用。此外，委员会认为， 衍生的小鼠RBC表现出正常的体内存活。 总之， 非免疫原性材料与完整RBC的共价连接可能具有 重要的临床应用。 这些包括但不限于 人红细胞的衍生化以允许患者输血 难以匹配，对次要RBC抗原过敏，可能 严重自身免疫性溶血性疾病的患者。

Red blood cell (RBC) transfusions are a crucial component in the treatment of a number of acute and chronic medical problems. In most acute injuries, simple RBC typing (ABO/Rh) is sufficient to identify appropriate donors. However, problems are frequently encountered in individuals, usually minorities, receiving chronic transfusions (e.g., sickle cell anemia and the thalassemias). Indeed, simple blood typing often becomes insufficient in determining a proper match as these individuals develop transfusion reactions to minor RBC antigens. This reactivity to minor RBC antigens can make it nearly impossible to identify appropriate blood donors. Thus, it would be desirable to artificially disguise cellular antigenic determinants to permit the survival of heterologous donor RBC and prevent allosensitization from occurring. To date this has not been possible. However, previous studies have demonstrated that the covalent linkage of poly(ethylene glycol) [PEG] to proteins both prolongs in vivo circulation and also prevents/diminishes protein antigenicity. Similarly, studies on liposomes have demonstrate that inclusion of PEG-conjugated lipids in the membrane also prolonged in vivo circulation. Based on these findings, it is the hypothesis of this proposal that the covalent binding of non-immunogenic, long chain polymers (e.g., PEG or PEG derivatives) to intact RBC can effectively mask the antigenic determinants on donor RBC, reduce RBC immunogenicity, and diminish/prevent transfusion reactions arising from disparity between donor and recipient RBC phenotypes. Therefore, the Specific Aims of this proposal are to determine: 1) which compounds effectively mask RBC antigenicity and examine how molecular weight and geometric shape (linear vs. branched) of PEG/PEG-derivatives affect cellular immunogenicity; 2) the structural, functional and metabolic consequences of RBC derivatization with PEG/PEG-derivatives; and 3) the effects of RBC-derivatization on in vitro and in vivo survival. As outlined within the proposal, preliminary studies using this technology demonstrates that derivatized human RBC are morphologically normal and exhibit significantly decreased: ABO/minor RBC antigenicity, immunogenicity, binding of anti-RBC antibodies and phagocytosis. Furthermore, derivatized mouse RBC exhibit normal in vivo survival. In sum, the covalent attachment of non-immunogenic materials to intact RBC may have significant clinical applications. These include, but are not limited to, derivatization of human RBC to permit transfusions in patients difficult to match, allosensitized to minor RBC antigens, and possibly in individuals with severe autoimmune hemolytic disease.