条纹斑竹鲨来源纳米抗体的筛选及作为药物载体应用的研究

The cartilaginous fish are the oldest group relative to mammals in which an adaptive immune system founded upon immunoglobulins has been found. IgNAR (Ig new antigen receptor) constitute a major fraction of the functional antibodies in the serum of cartilaginous fish. They are devoid of light chains and maintain the specificity and affinity to antigens. Through genetic engineering techniques, nanobody exhibits certain advantages such as low molecular weight, better stability as well as easy expression. In addition, through overcoming the limitations of low affinity and easy-to-aggregation, nanobody becomes one of the prestigious subtypes in the research and development of therapeutic antibodies. In Our preliminary research the full length of Chiloscyllium plagiosum IgNAR was cloned and the monomeric and multimeric IgNAR in the plasma of Chiloscyllium plagiosum have been identified. It was also demonstrated that an antigen-specific IgNAR response could be triggered in Chiloscyllium plagiosum after four boosts of HSA. Based on the special structure of Chiloscyllium plagiosum IgNAR, We will further carry out the following studies 1) the phage-display library will be used for panning on the nanobody specific to HSA; 2) E.coli will be used for expression and purification on the nanobody specific to HSA and the properties of nanobody specific to HSA will be investigated; 3) the binding kinetics of the anti-HSA nanobody/HSA interaction will be measured by BIAcore;4) the pharmacokinetic properties of biologics fused to an anti-HSA nanobody in mouse will be studied..We believe this project can help to establish an effective immunization route to raise high affinity IgNARs to target HSA.More importantly The Chiloscyllium plagiosum nanobody will become a valuable asset in both drug development and disease diagnosis.

软骨鱼类是拥有获得性免疫抗体最原始的物种，其体内存在一种只有重链组成的重链抗体—IgNAR（Ig new antigen receptor）。通过基因工程方法获得仅有IgNAR可变区，但保留结合能力的新型抗体—纳米抗体（nanobody）。本项目前期工作首次克隆得到了条纹斑竹鲨新颖重链抗体IgNAR，并在其血清中鉴定到了IgNAR。进一步用人血清白蛋白（HSA）对条纹斑竹鲨的免疫反应进行研究。 基于前期研究本项目拟开展以下研究: 1）优化条纹斑竹鲨的免疫方法并筛选条纹斑竹鲨来源抗HSA纳米抗体； 2）表达纯化抗HSA纳米抗体并对其稳定性研究；3)应用BIAcore系统等方法研究HSA与抗HSA纳米抗体的结合特性；4）研究条纹斑竹鲨来源抗HSA纳米抗体作为新型药物载体的可能性。项目的研究将为条纹斑竹鲨来源纳米抗体在新药研发、疾病诊断等方面的应用构建良好的平台，为新型抗体药物研发提供新的可能。

软骨鱼类是拥有获得性免疫抗体最原始的物种，其体内存在一种只有重链组成的重链抗体—IgNAR（Ig new antigen receptor）。通过基因工程获得仅有IgNAR可变区，但保留结合能力的新型抗体—纳米抗体（nanobody）。本项目前期工作首次克隆得到了条纹斑竹鲨来新颖重链抗体IgNAR，并在其血清中鉴定到了IgNAR。进一步用人血清白蛋白（HSA）对条纹斑竹鲨的免疫反应进行研究。本项目开展了以下研究: 1）优化条纹斑竹鲨的免疫方法并筛选条纹斑竹鲨来源抗HSA纳米抗体； 2）表达纯化抗HSA纳米抗体并对其稳定性研究；3)模拟研究HSA与抗HSA纳米抗体的结合位点。项目的研究将为条纹斑竹鲨来源纳米抗体在新药研发、疾病诊断等方面的应用构建良好的平台，为新型抗体药物研发提供新的可能。