石斑鱼黏膜IgM抗体来源及CCR6介导IgM阳性细胞归巢机制研究

刺激隐核虫病严重危害我国海水鱼养殖业，疫苗接种有望成为防控该病的重要手段。但刺激隐核虫诱导的黏膜获得性免疫应答机制尚未阐明，阻碍了刺激隐核虫疫苗的开发。申请人前期研究发现刺激隐核虫体表免疫与注射免疫产生的抗体应答及免疫保护效果存在差异，推测注射免疫产生的特异性IgM抗体或其阳性细胞无法有效到达黏膜所致。申请人进一步的研究发现趋化因子受体CCR6在刺激隐核虫体表感染后的石斑鱼黏膜部位表达显著上调，那么，CCR6作为鱼类黏膜IgM阳性细胞的重要表面受体之一，是否参与调控鱼类黏膜IgM阳性细胞的归巢？本项目拟利用刺激隐核虫局部感染模型，采用Western blot、Elispot、激光共聚焦、细胞屏蔽等技术研究石斑鱼黏膜IgM抗体来源及CCR6介导黏膜IgM阳性细胞的归巢机制，从而为刺激隐核虫疫苗开发奠定基础，具有重要的理论及应用价值。

Cryptocaryonosis cause heavy economic losses in marine aquaculture. Vaccination is expected to be an important mean for its prevention. However, the mechanism of the acquired immune response induced by Cryptocaryon irritans has not been elucidated, which hinders the development of vaccine. Our study showed that there are differences in the antibody response and immune protective effect between the surface immunity and the injection immunity. It is speculated that the specific IgM antibody produced by the injection immunity or its positive cells can not reach the mucosa effectively. Our further study showed that the expression of chemokine receptor CCR6 were significantly up-regulated in grouper mucosa post C. irritans infection. So, as one of the important surface receptors of IgM positive cells in fish mucosa, is CCR6 involved in regulating the homing of IgM positive cells in fish mucosa? In this project, Western blot, Elispot, laser confocal, cell deletion and other technologies are used to study the source of IgM antibody in grouper mucosa and the homing mechanism of CCR6 regulating IgM positive cells in grouper mucosa, so as to lay a foundation for the development of C. irritans vaccine, which has important theoretical and practical value.