不同接种途径诱导产生组织定居B细胞的特征、机制及其对疫苗免疫效果的影响

解析组织区域免疫应答对深入认识疫苗作用机制具有重要价值。但是，相较于对TRM的研究，目前对组织定居B细胞认识尚处于起步阶段。我们在前期工作中率先证明了疫苗在接种部位诱导产生的抗体应答会对系统免疫反应产生显著影响，并且发现DNA疫苗能够在注射部位诱导产生具有明显组织定居特征的抗原特异性B细胞。为进一步探讨疫苗诱导产生的组织定居B细胞的特征、机制及其对保护效果的影响，本课题将首先运用多色流式和单细胞测序技术在野生型或联体共生小鼠体内解析不同接种途径诱导产生的组织定居B细胞在组织分布、表型与功能特征方面的差异；随后，运用免疫荧光、免疫组化等原位检测技术在特异性T、B细胞过继小鼠体内观察Th细胞在组织定居B细胞形成与维持过程中的作用；最后，采用流感病毒攻击模型来观察组织定居B细胞对再次抗体应答和疫苗保护效果的影响。本课题的顺利实施既有助于深化对组织定居B细胞的认识，也可为今后的疫苗研发提供新思路。

The analysis of regional immune responses in multiple organs is of great value in understanding the mechanisms of vaccine protection. However, compared with the accumulated knowledge of TRM, the investigation of tissue-resident B cells is just getting started. In our previous work, we demonstrated for the first time that specific antibody responses elicited by a DNA vaccine at the inoculation site significantly influenced systemic immune responses and found that DNA vaccine was able to induce antigen-specific B cells with obvious tissue-resident features at the injection site. To further characterize vaccination induced tissue-resident B cells and clarify their roles in vaccine efficacy, in this study, we will first analyze the distribution, phenotype and function of tissue-resident B cells induced via different inoculation routes in wild type or parabiotic mice by using multi-parameter flowcytometry and single cell sequencing techniques. Next, by employing in-situ detection techniques, such as immunofluorescence and immunohistochemistry, the potential roles of Th cells in the induction and maintenance of tissue-resident B cells will be investigated in antigen-specific T cell and B cell transferred mice. Finally, influenza virus challenging model will be used to observe the influence of tissue-resident B cells on secondary antibody response and vaccine protection. This study will not only shed new light on the understanding of tissue-resident B cells, but also provide novel ideas for vaccine research and development in future.