Interaction of antibodies with liposomes bearing fluorescent haptens.
Interaction of antibodies with liposomes bearing fluorescent haptens.
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抗体与带有荧光半抗原的脂质体的相互作用。
DOI：
10.1016/0005-2736(84)90211-6
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发表时间：
1984
期刊：
影响因子：
--
通讯作者：
Owicki,JC
中科院分区：
文献类型：
--
作者：
Petrossian,A;Owicki,JC
已经研究了抗体识别抗原模型膜的动力学和平衡方面。允许单克隆抗荧光素IgG及其单价Fab片段与掺入磷脂囊泡中的荧光素-脂质半抗原相互作用。通过监测抗体对半抗原荧光的淬灭，在纳摩尔半抗原浓度范围内测定结合。结合的速率和强度取决于囊泡的脂质组成;胆固醇增强两者。对于某些组合物，在高抗体浓度下观察到的双相结合动力学，加上额外的光谱证据，使我们假设半抗原存在于至少两种构象之间的组合物依赖性平衡中：（1）远离膜表面延伸，可用于结合，和（2）隔离在表面处或表面中，不可用于结合。IgG结合的速率和强度总是大于Fab的速率和强度，表明IgG的二价结合。这种结合是囊泡内的，因为没有检测到囊泡的凝集。
Kinetic and equilibrium aspects of the recognition of antigenic model membranes by antibodies have been studied. Monoclonal anti-fluorescein IgG and its monovalent Fab fragment were allowed to interact with a fluorescein-lipid hapten that was incorporated into phospholipid vesicles. The binding was assayed in the nanomolar hapten concentration range by monitoring the quenching of hapten fluorescence by antibody. The rate and strength of the binding depended on the lipid composition of the vesicles; cholesterol enhanced both. The biphasic binding kinetics observed at high antibody concentrations for some compositions, plus additional spectroscopic evidence, led us to hypothesize that the hapten existed in a composition-dependent equilibrium between at least two conformations: (1) extended away from the membrane surface, available for binding, and (2) sequestered at or in the surface, unavailable for binding. The rate and strength of IgG binding were always greater than those of Fab, indicating bivalent binding by the IgG. This binding was intra-vesicular, since no agglutination of the vesicles was detected.