Immunoassay with High Sensitivity by Using Immunoliposomes and Membrane Lysis Reaction of the Complement System

免疫分析技术依靠抗原与抗体之间的高亲和力和高灵敏度，广泛应用于微量分析和临床检测。然而，目前的固相免疫测定法需要分离结合抗体和游离抗体，因此耗时且麻烦。本文报道了一种新的免疫脂质体均相免疫分析方法. e.脂质体与抗体（抗原）偶联。在该方法中，这些脂质体被补体系统在形成抗原-抗体复合物时的裂解反应破坏，并且脂质体包封的标记物的释放量用作反应发生的定量指示。主要研究结果如下：1.免疫脂质体在含有明胶的缓冲液中稳定数月，包封标记物无任何损失.偶联兔IgG的免疫脂质体主要通过补体的旁路途径被破坏。加入抗兔IgG抗体后，由于补体经典途径的激活，标记物的释放显著增强。利用免疫脂质体可以在同一系统中检测两条通路的活性.与抗原偶联的免疫脂质体通过加入针对抗原的特异性抗体而被破坏。标记物释放与免疫脂质体表面上形成的抗原-抗体复合物的量成比例。

Immunoassays, which depend on the high affinity and sensitivity between antigen and antibody, are widely used in microanalyses and clinical assays. The present solid-phase immunoassays, however, need separation between bound and free antibodies and so are time-consuming and troublesome. In the present work a new homogeneous immunoassay by using immunoliposomes, i. e. liposomes coupled with antibodies (antigens), was developed. In this method, these liposomes are destroyed by the lysis reaction of the complement system on the formation of antigen-antibody complexes, and the released amount of liposome-encapsulated marker serves as a quantitative indication of the reaction taking place. The results are summarized as follows :1. The immunoliposomes were stable in buffer solutions containing gelatin for several months without any loss of encapsulated marker.2. The immunoliposomes coupled with rabbit IgG were destroyed mainly by the alternative pathway of complement. Addition of anti-rabbit IgG antibody enhanced significantly marker release because of the activation of the classical pathway of complement. The activities of both the pathways can be measured in the same system by using the immunoliposomes.3. The immunoliposomes coupled with an antigen were destroyed by addition of the specific antibody against the antigen. The marker release was proportional to the amount of antigen-antibody complexes formed on the surface of the immunoliposomes.