Shibuya-Fujiwara N, Hirayama F, Ogata Y, Ikeda H, Ikebuchi K
Hokkaido Red Cross Blood Center, Sapporo, Japan.
Life Sci. 2001 Dec 7;70(3):291-300. doi: 10.1016/s0024-3205(01)01392-3.
Liposome-encapsulated hemoglobin (LEH), a candidate for red blood cell substitute, is cleared from circulation primarily by the phagocytic system, most likely after opsonization of the vesicles by immunoproteins, particularly complement components. Although modification of LEH by polyethylene glycol (PEG) derivatives prolongs its half-life by blocking the opsonization, the half-life is still short as compared with that of red blood cell components. Therefore, this study was performed to elucidate the opsonin-independent mechanisms that regulate phagocytosis of Neo Red Cell (NRC), a PEG-modified LEH, in culture. PKH67 was used as a fluorescence marker, allowing the quantitation of the phagocytosis of NRC by peripheral blood monocytes plus macrophages. The phagocytosis of PKH67-labeled NRC was inhibited by the addition of an excess of unlabeled NRC, indicating that the phagocytosis of PKH67-labeled NRC is specific to NRC, but not to PKH67. The phagocytosis of NRC was blocked about 70% by anti-CD14, 60% by anti-CD36 and 30% by anti-CD51/61 (vitronectin receptor, alpha(v)beta3). These results provided evidence of an opsonin-independent pathway for the phagocytosis of PEG-modified LEH.
脂质体包裹的血红蛋白（LEH）作为红细胞替代物的候选者，主要通过吞噬系统从循环中清除，很可能是在免疫蛋白，特别是补体成分对囊泡进行调理作用之后。尽管用聚乙二醇（PEG）衍生物修饰LEH可通过阻断调理作用延长其半衰期，但与红细胞成分相比，其半衰期仍然较短。因此，本研究旨在阐明在培养中调节聚乙二醇修饰的LEH——新型红细胞（NRC）吞噬作用的不依赖调理素的机制。PKH67用作荧光标记物，可对外周血单核细胞加巨噬细胞对NRC的吞噬作用进行定量。加入过量未标记的NRC可抑制PKH67标记的NRC的吞噬作用，这表明PKH67标记的NRC的吞噬作用对NRC具有特异性，而对PKH67没有特异性。抗CD14可使NRC的吞噬作用阻断约70%，抗CD36可阻断60%，抗CD51/61（玻连蛋白受体，α(v)β3）可阻断30%。这些结果为聚乙二醇修饰的LEH的吞噬作用提供了一条不依赖调理素的途径的证据。
