微囊藻毒素抗体的广谱特异性结构基础与定向调控研究

具有广谱识别性能的抗体因可以实现多残留检测而成为当前食品污染物免疫分析的研究热点，深入研究抗体的广谱特异性结构基础，对于实现其分析性能的人工调控具有重要意义。本项目拟在前期已获得可同时识别微囊藻毒素和节球藻毒素的广谱特异性单克隆抗体基础上，酶解单抗获取抗原结合片段（Fab），制备Fab单晶及其与多种藻毒素的复合物晶体，利用X-射线衍射技术解析晶体结构，明确藻毒素抗体广谱特异性的关键位点信息，结合抗体特异性、灵敏度、亲和力等参数以及计算机辅助虚拟筛选、反向PCR等手段，进行关键残基的定点突变，评价分析突变体活性，阐释广谱性识别差异机制，实现藻毒素抗体特异性的定向调控。该研究对于指导半抗原类物质的抗体改造、构效关系、免疫分析方法等研究，具有重要科学意义。

Research on antibodies with broad specificity is a hot area in immunoassay due to its strong simultaneous screening capability to multi-analyte. Thus, it is of great significance to investigate the structure basis of the broad specificity of antibodies for better understanding and the artificial control of the immunoassay performance. Previously, we have obtained three broad specificity monoclonal antibodies with a recognition to both microcystins and nodularin. In this investigation, the fragment of antigen-binding (Fab) would be prepared by enzymatic digestion of monoclonal antibodies. The key site information of the broad specific fragment would be cleared with the X-ray diffraction analysis based on the crystal structure of Fab and its complex. The site-directed mutagenesis is carried out to the key residues and to evaluate the activity of mutants, and then the different recognition mechanism of the broad specificity can be explained. Finally, the antibody broad specificity combined with the antibody specificity, sensitivity, affinity will be regulable, based on computer assisted virtual screening, reverse PCR and so on. This research is of important scientific significance to the antibody modifying, hapten design, structure-activity relationship and immunoassay development.