Glaser R W, Hausdorf G
Department of Medical Immunology, Humboldt University Berlin, Medical School (Charité), Germany.
J Immunol Methods. 1996 Jan 16;189(1):1-14. doi: 10.1016/0022-1759(95)00221-9.
The interaction between HIV core protein p24 and the murine monoclonal antibody CB-4/1 or its Fab fragment showed unusual kinetics. Recombinant p24 was immobilised in a hydrophilic carboxymethyldextran matrix. At high concentration of CB-4/1 Fab the association of the antigen-antibody complex proceeds in two phases, while dissociation is mono-exponential. The antigen has a 'memory', i.e. shortly after dissociation of Fab-antigen complex the fast association phase is enhanced. Biphasic association was also found in solution. Experiments suggest a reversible change of binding properties in the epitope region with an overall time constant of about 100 s at room temperature. Intermediate steps with faster time constants must be involved. Slow conformational changes of p24 seem to be the most probable explanation. A simple model that provides a quantitative description of this process could not be found. Real-time analysis of antibody binding by surface plasmon resonance is a powerful method for studying such changes in the time domain of a few seconds to a few minutes.
HIV核心蛋白p24与鼠单克隆抗体CB-4/1或其Fab片段之间的相互作用呈现出不同寻常的动力学特征。重组p24固定在亲水性羧甲基葡聚糖基质中。在高浓度的CB-4/1 Fab存在时，抗原-抗体复合物的结合过程分两个阶段进行，而解离过程是单指数形式的。抗原具有“记忆”功能，即Fab-抗原复合物解离后不久，快速结合阶段会增强。在溶液中也发现了双相结合现象。实验表明，在室温下，表位区域的结合特性发生了可逆变化，其总体时间常数约为100秒。必然涉及到具有更快时间常数的中间步骤。p24的缓慢构象变化似乎是最有可能的解释。尚未找到能对这一过程进行定量描述的简单模型。通过表面等离子体共振对抗体结合进行实时分析是研究在几秒到几分钟时域内此类变化的有力方法。
