Bin1b 是一个在雄性动物生殖器官附睾中专一表达的防御素，在进化上高度保守,具有广普的抗菌活性；Bin1b能控制精子对钙离子的摄取从而起动精子的运动；该基因过表达，小鼠能够显著提高转基因动物对大肠杆菌感染的抵抗，对动物的生殖道和精子具有保护作用，同时抑制炎症因子如IL1a和IL1b的表达。以上关于Bin1b的重要研究均在申请者所在实验室完成。我们在研究中还发现，Bin1b的过表达显著的减弱了动物对金黄色葡萄球菌的感染的抵抗能力，这提示防御素在免疫系统中具有多方面的调节作用，不同的防御素可能需要和其他防御素或其他的免疫分子相互平衡才能更有效的保护机体。本研究将通过转基因动物和基因剔除动物，运用分子、细胞、生化及免疫生物学的手段，研究Bin1b影响附睾免疫的具体功能和机制，以及Bin1b对雄性生育的必要性，为今后更好开展防御素的研究奠定基础，也为今后防御素的临床应用提供理论指导。

Bin1b belongs to beta-defensin predominantly expressed in epididymis, and conserved in evolution. It contains powerful antimicrobial activity with role to promote motility of sperm. Overexpression of Bin1b in epididymis enhanced transgenic mice resistance to E.coli infection, increased protection of sperm, at the same time suppressed cytokines expression such as Il1a and IL1b. Above studied was finished in your lab. Recently we found Bin1b transgenic mice susceptible to S.aureus infection. Thus is suggested that beta-defensin play multiple roles in regulation of immune response. It is possible that multiple defensin works together to balance immunity defense. Using Bin1b transgenic and knock out mice model, and with the help of molecular,cell biology ,biochemistry and immunological techniques, our study will focus on study the function and mechanism of Bin1b in protection epididymitis , and the role of Bin1b in male fertility. This study will provide methods and help for further study others beta defensin, and will provide guidance in clinical use of beta defensin.