Research Unit of Congenital and Perinatal Infections, Academic Department of Pediatrics, Bambino Gesù Children's Hospital-Research Institute, 00165 Rome, Italy.
Department of Systems Medicine, University of Rome Tor Vergata, 00133 Rome, Italy.
J Immunol. 2018 Jan 15;200(2):538-550. doi: 10.4049/jimmunol.1701312. Epub 2017 Dec 13.
Generation of Ag-specific humoral responses requires the orchestrated development and function of highly specialized immune cells in secondary lymphoid organs. We used a multiparametric approach combining flow cytometry, confocal microscopy, and histocytometry to analyze, for the first time to our knowledge in children, tonsils from seasonal influenza-vaccinated children. We used these novel imaging assays to address the mucosal immune dynamics in tonsils investigating the spatial positioning, frequency, and phenotype of immune cells after vaccination. Vaccination was associated with a significantly higher frequency of follicular helper CD4 T cells compared with the unvaccinated control group. The imaging analysis revealed that potential suppressor (FOXP3) CD4 T cells are mainly located in extrafollicular areas. Furthermore, a significantly reduced frequency of both follicular and extrafollicular FOXP3 CD4 T cells was found in the vaccine group compared with the control group. Levels of circulating CXCL13 were higher in those vaccinated compared with controls, mirroring an increased germinal center reactivity in the tonsils. Notably, a strong correlation was found between the frequency of tonsillar T follicular helper cells and tonsillar Ag-specific Ab-secreting cells. These data demonstrate that influenza vaccination promotes the prevalence of relevant immune cells in tonsillar follicles and support the use of tonsils as lymphoid sites for the study of germinal center reactions after vaccination in children.
产生针对抗原的体液免疫应答需要在次级淋巴器官中协调发育和功能的高度专业化免疫细胞。我们使用了一种多参数方法，结合流式细胞术、共聚焦显微镜和组织细胞计量学，首次在季节性流感疫苗接种的儿童扁桃体中进行了分析。我们使用这些新的成像检测方法来研究扁桃体中的黏膜免疫动力学，调查接种疫苗后免疫细胞的空间定位、频率和表型。与未接种疫苗的对照组相比，接种疫苗后滤泡辅助性 CD4 T 细胞的频率明显更高。成像分析显示，潜在的抑制性（FOXP3）CD4 T 细胞主要位于滤泡外区域。此外，与对照组相比，疫苗组的滤泡内和滤泡外 FOXP3 CD4 T 细胞的频率均显著降低。与对照组相比，接种疫苗组的循环 CXCL13 水平更高，反映了扁桃体生发中心反应增强。值得注意的是，扁桃体滤泡辅助性 T 细胞的频率与扁桃体抗原特异性 Ab 分泌细胞之间存在很强的相关性。这些数据表明，流感疫苗接种促进了扁桃体滤泡中相关免疫细胞的流行，并支持将扁桃体作为研究儿童接种疫苗后生发中心反应的淋巴样部位。
