Tamm L K
Department of Biophysical Chemistry, University of Basel, Switzerland.
Biochemistry. 1988 Mar 8;27(5):1450-7. doi: 10.1021/bi00405a009.
Supported phospholipid bilayers prepared by Langmuir-Blodgett techniques were introduced recently as a new model membrane system [Tamm, L.K., & McConnell, H.M. (1985) Biophys. J. 47, 105-113]. Here, supported bilayers are applied to study the lateral diffusion and lateral distribution of membrane-bound monoclonal antibodies. A monoclonal anti-trinitrophenol antibody was found to bind strongly and with high specificity to supported phospholipid bilayers containing the lipid hapten (trinitrophenyl)phosphatidylethanolamine at various mole fractions. The lateral distribution of the membrane-bound antibodies was studied by epifluorescence microscopy. The bound antibodies aggregated into patches on a host lipid bilayer of dimyristoylphosphatidylcholine below the lipid chain melting phase transition and redistributed uniformly on fluid-phase supported bilayers. Lateral diffusion coefficients and mobile fractions of fluorescent phospholipid analogues and fluorescein-labeled antibodies were measured by fluorescence recovery after pattern photobleaching. The lateral diffusion coefficients of the membrane-bound antibodies resembled those of the phospholipids but were reduced by a factor of 2 in the fluid phase. The lipid chain melting phase transition was also reflected in the lateral diffusion coefficient of the bound antibody but occurred at a temperature about 3 deg higher than the phase transition in supported bilayers of pure phospholipids. The antibody lateral diffusion coefficients decreased in titration experiments monotonically with increasing antibody surface concentrations by a factor of 2-3. Correspondingly, a relatively small decrease of the antibody lateral diffusion coefficient was observed with increasing mole fractions of lipid haptens in the supported bilayer.
最近，通过朗缪尔-布洛杰特技术制备的支撑磷脂双层作为一种新的膜模型系统被引入[塔姆，L.K.，& 麦康奈尔，H.M.（1985年）《生物物理杂志》47卷，第105 - 113页]。在此，支撑双层被用于研究膜结合单克隆抗体的横向扩散和横向分布。发现一种抗三硝基苯酚单克隆抗体能强烈且高度特异性地结合到含有不同摩尔分数脂质半抗原（三硝基苯基）磷脂酰乙醇胺的支撑磷脂双层上。通过落射荧光显微镜研究膜结合抗体的横向分布。在低于脂质链熔化相变温度时，结合的抗体在二肉豆蔻酰磷脂酰胆碱的主体脂质双层上聚集成斑块，而在液相支撑双层上均匀重新分布。通过图案光漂白后的荧光恢复测量荧光磷脂类似物和荧光素标记抗体的横向扩散系数和可移动部分。膜结合抗体的横向扩散系数与磷脂的相似，但在液相中降低了2倍。脂质链熔化相变也反映在结合抗体的横向扩散系数中，但发生温度比纯磷脂支撑双层中的相变温度高约3℃。在滴定实验中，抗体横向扩散系数随抗体表面浓度增加而单调降低，降低了2 - 3倍。相应地，随着支撑双层中脂质半抗原摩尔分数增加，观察到抗体横向扩散系数有相对较小的降低。
