动物性食品中兽药多残留免疫分析法的核心是广谱特异性抗体。本项目拟分别合成吩噻嗪类和苯二氮卓类药物的通用半抗原，制备两类兽药各自的广谱单克隆抗体；以杂交瘤中编码抗体轻、重链可变区的基因片断为基础，制备两类兽药各自的广谱ScFv抗体，以ELISA法检测Scfv抗体对同类药物的交叉反应性和灵敏度。通过计算机模拟分别对两种Scfv抗体进行蛋白同源模建，获得抗体的三维构象，以分子对接技术建立抗体-抗原互作模型，研究抗体对兽药的分子识别机制（识别位点、关键氨基酸和结合模式）；分别对编码两种ScFv抗体的基因片断进行定向改造，制备两种新的ScFv抗体，以提高抗体性能，并研究抗体的分子识别机制。将两种Scfv抗体的基因片断连接，制备能同时识别吩噻嗪类和苯二氮卓类药物的广谱双特异ScFv抗体用于动物性食品中这两类药物的残留检测。本研究结果将为研究其他兽药的双/多特异性ScFv抗体及其识别机制奠定基础。

The core reagent during the development of an immunoassay for multi-determination of different classes of veterinary drugs in animal original foods is the broad specific antibody. In this project application, the generic haptens of phenothiazines drugs and benzodiazepines drugs are synthesized respectively, with which to produce the respective generic monoclonal antibody of the two classes of drugs. The gene fractions that encoded the variable region of antibody heavy-chain and light-chain in different hybridoma cells are extracted and used to produce the respective recombinant Scfv antibody of the two classes of drugs. The sensitivity and specificity of the two Scfv antibodies for respective class of drugs are determined by using of competitive ELISA method. Then, the homology modeling for the two Scfv antibodies are performed by using of the computer simulation and the antibody-hapten interactions are simulated by using of Molecular Docking technique to determine the molecular recognition mechanism of the two Scfv antibodies, including recognition positions, key amino acids and binding model. In order to improve the antibody performances, the gene fractions that encoded the two Scfv antibodies are subjected to directional transformation. Based on the obtained optimal gene fractions, the optimized broad specific Scfv antibodies for phenothiazines drugs and benzodiazepines drugs are produced respectively and the molecular recognition mechanisms of the two Scfv antibodies are studied again. Then the recombinant bi-specific Scfv antibody simultaneous recognizing the two classes of drugs is produced based on the obtained optimal gene fractions and used to determine the residues of the two classes of drugs in animal original foods. The results of this study will provide the basis for production of the bi-specific or multi-specific antibodies of other veterinary drugs and help to study their molecular recognition mechanism.