Richards R L, Habbersett R C, Scher I, Janoff A S, Schieren H P, Mayer L D, Cullis P R, Alving C R
Biochim Biophys Acta. 1986 Feb 27;855(2):223-30. doi: 10.1016/0005-2736(86)90168-9.
Complement-dependent antibody-mediated damage to multilamellar lipid vesicles (MLVs) normally results in a maximum release of 50-60% of trapped aqueous marker. The most widely accepted explanation for this is that only the outermost lamellae of MLVs are attacked by complement. To test this hypothesis, complement damage to two different types of large unilamellar vesicles (LUVs), large unilamellar vesicles prepared by the reverse-phase evaporation procedure (REVs) and large unilamellar vesicles prepared by extrusion techniques (LUVETs), were determined. In the presence of excess antibody and complement the LUVs released a maximum of only approx. 25 to 40% of trapped aqueous marker, instead of close to 100% that would be expected. Since small unilamellar vesicles apparently differ from LUVs in that they can release 100% of trapped aqueous marker it appeared that the size of the vesicles was an important factor. Because of these observations the influence of MLV size on marker release was examined. Three populations of MLVs of different sizes were separated by a fluorescence activated cell sorter. Assays of the separated MLV populations showed that the degree of complement-dependent marker release was inversely related to MLV size. No detectable glucose was taken up by MLVs when glucose was present only outside the liposomes during complement lysis. Our results can all be explained by the closing, or loss, of complement channels. We conclude that complement channels are only transiently open in liposomes, and that loss of channel patency may be due to either channel closing or to loss of channels.
补体依赖性抗体介导的对多层脂质囊泡（MLV）的损伤通常导致所包裹的水性标记物最多释放50% - 60%。对此最广泛接受的解释是MLV只有最外层的脂质双层会受到补体攻击。为了验证这一假设，我们测定了补体对两种不同类型的大单层囊泡（LUV）的损伤情况，即通过反相蒸发法制备的大单层囊泡（REV）和通过挤压技术制备的大单层囊泡（LUVET）。在存在过量抗体和补体的情况下，LUV最多仅释放约25%至40%的所包裹的水性标记物，而不是预期的接近100%。由于小单层囊泡显然与LUV不同，它们可以释放100%的所包裹的水性标记物，所以囊泡大小似乎是一个重要因素。基于这些观察结果，我们研究了MLV大小对标记物释放的影响。通过荧光激活细胞分选仪分离出了三种不同大小的MLV群体。对分离出的MLV群体的检测表明，补体依赖性标记物释放程度与MLV大小呈负相关。在补体裂解过程中，当葡萄糖仅存在于脂质体外部时，MLV未摄取到可检测到的葡萄糖。我们的结果都可以用补体通道的关闭或丧失来解释。我们得出结论，补体通道在脂质体中只是短暂开放，通道通畅性的丧失可能是由于通道关闭或通道丧失。
