基于抗原-抗体特异性结合的血清肿瘤标志物CA125和HE4联合检测有助于建立方便、经济、高效的卵巢癌早期诊断方法，提高患者的生存率。但是对CA125和HE4纳米抗体结构与功能的深入研究未见报道，极大限制了卵巢癌早期诊断方法的建立。本项目前期工作已获得具有天然构象的CA125和重组表达的HE4抗原，基于该基础，本研究通过免疫羊驼和噬菌体展示技术获得CA125和HE4的纳米抗体，结合生物学和生物信息技术确定抗原表位，着重从分子水平阐明纳米抗体结合抗原的作用机制，解析纳米抗体结构与其高稳定性的关系。本研究将为其他肿瘤标记物的纳米抗体研究提供参考，为解析纳米抗体结构与功能关系的普遍规律奠定基础。本研究通过定向设计，开发具有更高灵敏度、更高稳定性的新型纳米抗体，为建立方便、经济、高效的卵巢癌早期诊断方法提供理论依据，有助于推动卵巢癌的常规筛查，降低卵巢癌的死亡率，具有重要的理论和现实意义。

Based on the specific binding of antibody to antigen, the joint detection of serum tumor markers including CA125 and HE4 will contribute to the establishment of convenient, economical and efficient method for early diagnosis of ovarian cancer and increase the survivability of patients significantly. However, the research for the function and structure of nanobodies against CA125 and HE4 has not been reported, which tremendously impede the establishment of early diagnostic method of ovarian cancer. In our previous study, we have prepared the CA125 antigen with native conformation and recombinant HE4 antigen. Based on the above basis, we will prepare the nanobodies against CA125 and HE4 antigens through alpacas immunization and phage display technology. This project will focus on clarifying the mechanisms underlying the molecular recognition between antigens and nanobodies at the molecular level and analyzing the relationship between the structure of nanobodies and their high stability. This project will provide reference for the study of nanobodies against other tumor markers, and lay the foundation for analyzing the general rule of the relationship between the structure and function of nanobodies. Novel nanobodies with higher sensitivity and greater stability will be developed by rational design, which will help to provide the theoretical basis for the establishment of convenient, economical and efficient method for early diagnosis of ovarian cancer. It has important theoretical and practical significance for promoting routine screening and reducing the mortality of ovarian cancer.