Yamada M, Harashima H, Kiwada H
Faculty of Pharmaceutical Sciences, The University of Tokushima, Japan.
Biol Pharm Bull. 1998 Sep;21(9):964-8. doi: 10.1248/bpb.21.964.
The size of liposomes is considered to be an important factor in determining the liposome-complement interaction. In this study, the release of carboxyfluorescein (CF) from liposomes was measured continuously for three different diameters (800, 400 and 200 nm) by changing the liposome concentration from 1 to 1000 nmol/ml. At a low liposome concentration range (1-10 nmol/ml), small liposomes (200 nm) released CF to a similar extent (approximately 35%) as in the medium (400 nm) and large (800 nm) liposomes. The affinity (Km) and capacity (Lmax) of a complement system to release liposomally encapsulated CF were estimated by kinetic analysis of the liposome-complement interaction. Surprisingly, there was no remarkable size dependency in the Km and Lmax in terms of liposome number, although these parameters depended on the size of liposomes in terms of lipid concentration. These results indicated the possibility that the complement system does not discriminate according to liposome size.
脂质体的大小被认为是决定脂质体与补体相互作用的一个重要因素。在本研究中，通过将脂质体浓度从1纳摩尔/毫升改变至1000纳摩尔/毫升，连续测量了三种不同直径（800纳米、400纳米和200纳米）的脂质体中羧基荧光素（CF）的释放情况。在低脂质体浓度范围（1 - 10纳摩尔/毫升）内，小脂质体（200纳米）释放CF的程度与中等大小（400纳米）和大脂质体（800纳米）相似（约35%）。通过对脂质体 - 补体相互作用的动力学分析，估算了补体系统释放脂质体包裹的CF的亲和力（Km）和容量（Lmax）。令人惊讶的是，就脂质体数量而言，Km和Lmax没有显著的大小依赖性，尽管这些参数在脂质浓度方面取决于脂质体的大小。这些结果表明补体系统可能不会根据脂质体大小进行区分。
