Injection of PEGylated liposomes in rats elicits PEG-specific IgM, which is responsible for rapid elimination of a second dose of PEGylated liposomes
Injection of PEGylated liposomes in rats elicits PEG-specific IgM, which is responsible for rapid elimination of a second dose of PEGylated liposomes
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DOI：
10.1016/j.jconrel.2006.01.005
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发表时间：
2006-05-01
影响因子：
10.8
通讯作者：
Kiwada, H
中科院分区：
文献类型：
--
作者：
Ishida, T;Ichihara, M;Kiwada, H
通过PEG缀合的脂质对脂质体表面的空间稳定导致单核吞噬细胞系统的细胞对脂质体的识别减少，从而延长其循环时间（在大鼠中t（1/2）约为20 h）。最近，我们报道了“加速血液清除现象”，导致“不可见的”PEG化脂质体在重复注射后从循环中非常迅速地清除。此外，我们报告了在第一剂PEG化脂质体后分泌到血液中的某些血清因子在该现象中起重要作用。本研究的目的是确定主要的血清蛋白（S）负责的现象，并解开他们的行动模式。在与血清孵育期间，与PEG化脂质体结合的蛋白质的量与该现象的程度几乎不相关。如2D-PAGE和SDS-PAGE所示，与5天前用相同脂质体预注射的大鼠血清孵育的PEG化脂质体显示出比与初始血清孵育时更复杂的结合蛋白模式。随后的LC-MS/MS和Western blot分析表明，与PEG化脂质体结合的主要预处理血清蛋白是IgM。半定量分析表明，与常规脂质体相比，更大量的IgM结合到PEG化脂质体。进一步证明，当在来自用PEG化脂质体预注射的大鼠的血清中孵育时，PEG化脂质体可由于IgM结合而激活补体系统，而常规脂质体则不能。这些结果表明，IgM与第二次注射的PEG化脂质体的选择性结合和随后的IgM补体激活导致第二次注射的PEG化脂质体的加速清除和增强的肝脏摄取。基于本文所述的结果，我们提请注意静脉内给予聚乙二醇化脂质体或其他颗粒以及延伸的聚乙二醇化蛋白质和DNA后可能发生的非预期免疫反应。(c)2006 Elsevier B. V.保留所有权利。
Steric stabilization of the surface of liposomes by a PEG conjugated lipid results in reduced recognition of the liposomes by the cells of the mononuclear phagocyte system and consequently extended their circulation times (t(1/2) approximate to 20 h in rat). Recently, we reported on the "accelerated blood clearance phenomenon", causing 'invisible' PEGylated liposomes to be cleared very rapidly from the circulation upon repeated injection. In addition, we reported that certain serum factor(s) secreted into the blood after the first dose of PEGylated liposomes play an essential role in the phenomenon. The aim of the present study was to identify the major serum protein(s) responsible for the phenomenon and to unravel their mode of action. The amount of protein binding to PEGylated liposomes during incubation with serum hardly correlated with the extent of the phenomenon. PEGylated liposomes incubated with serum obtained from rats pre-injected 5 days before with the same liposomes showed a much more complex pattern of bound proteins than when incubated with naive serum, as revealed by 2D-PAGE and SDS-PAGE. Subsequent analysis with LC-MS/MS and Western blot showed that the major pre-treated serum protein binding to PEGylated liposomes was IgM. Semi-quantitative analysis showed that larger amount of IgM bound to PEGylated liposomes compared to conventional liposomes. It was further demonstrated that PEGylated liposomes could activate the complement system due to IgM binding when incubated in serum from rats pre-injected with PEGylated liposomes, while conventional liposomes were not. These findings suggest that the selective binding of IgM to the second injected PEGylated liposomes and the subsequent complement activation by IgM resulted in the accelerated clearance and enhanced hepatic uptake of the second injected PEGylated liposomes. Based on the results described here, we are drawing attention to the potential occurrence of unexpected immune reactions upon intravenous administration of PEGylated liposomes or other particles and, by extension, PEGylated proteins and DNAs. (c) 2006 Elsevier B.V. All rights reserved.