Shen Erxia, Wang Mengjie, Xie Hairui, Zou Ruqiong, Lin Qiwen, Lai Lili, Li Fujun, Liang Zhimei, Xu Yanran, Zhou Maohua
Department of Pathogenic Biology and Immunology, Sino-French Hoffmann Institute, School of Basic Science, Guangzhou Medical University, Guangzhou, 510182, China.
Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA.
BMC Immunol. 2016 Jun 23;17(1):20. doi: 10.1186/s12865-016-0158-8.
Children are prone to get infections, especially in the respiratory system and the gut mainly because their immune system is immature. T cells significantly contribute to the prevention of infections, and different helper T cell (Th) subsets play different anti-pathogen roles. Interleukin (IL)-22 producing by T-helper 22 cells (Th22) play an important role in host defense against Gram-negative bacterial organisms in gut and lung. T-helper 17 cells (Th17) protect against extracelluar bacteria and fungi especially at the epithelial surface. However, there is no report comparing IL-22 producing T cells and Th17 cells in healthy young children to adults.
Flow cytometry (FCM) was used to observe whether Th22 subset existed in the peripheral blood of healthy young children. Meanwhile, we determined the frequencies of Th subsets including Th17, Th1 and Th2, cytotoxic T (Tc)1 subset, CD4+ and CD8+ memory T cells in the peripheral blood of both young children and adults.
In the present study, we demonstrated that Th22 subset existed in peripheral blood of children, with IL-22 mainly secreted by CD4 + CD45RO+ memory T cells. Moreover, we observed that IL-22 + CD4 + T cells and Th subsets including Th17, Th1, and Th2 frequencies of young children (1-6 years old) were significantly lower than adults. While the Th1 frequency from Group A (1-3 years old) was markedly lower than that from Group B (4-6 years old). No significant differences of Th17 or IL-22 + CD4 + T cells frequencies were observed between these two groups. In addition, Tc1 subset frequencies were also remarkably lower in young children than in adults. Furthermore, lower frequencies of CD45RO+ memory CD4+ and CD8+ T cells in young children than in adults, and significant correlation between CD45RO+ memory CD4 + T cells and IL-22 + CD4 + T cells, Th1, Th17 were observed.
Th22 subset exists in the peripheral blood of young children. Compared with adults, there are lower frequencies of IL-22 + CD4 + T cells, as well as Th1, Th17, Th2 and Tc1 subsets in the peripheral blood of young children.
儿童容易受到感染，尤其是呼吸系统和肠道感染，主要是因为他们的免疫系统不成熟。T细胞对预防感染有重要作用，不同的辅助性T细胞（Th）亚群发挥不同的抗病原体作用。辅助性T22细胞（Th22）产生的白细胞介素（IL）-22在宿主抵抗肠道和肺部革兰氏阴性细菌病原体的防御中起重要作用。辅助性T17细胞（Th17）尤其在上皮表面抵御细胞外细菌和真菌。然而，尚无关于健康幼儿与成人中产生IL-22的T细胞和Th17细胞比较的报道。
采用流式细胞术（FCM）观察健康幼儿外周血中是否存在Th22亚群。同时，我们测定了幼儿和成人外周血中Th亚群的频率，包括Th17、Th1和Th2、细胞毒性T（Tc）1亚群、CD4 +和CD8 +记忆T细胞。
在本研究中，我们证明Th22亚群存在于儿童外周血中，IL-22主要由CD4 + CD45RO +记忆T细胞分泌。此外，我们观察到幼儿（1 - 6岁）的IL-22 + CD4 + T细胞以及Th17、Th1和Th2亚群的频率显著低于成人。而A组（1 - 3岁）的Th1频率明显低于B组（4 - 6岁）。这两组之间Th17或IL-22 + CD4 + T细胞频率未观察到显著差异。此外，幼儿的Tc1亚群频率也明显低于成人。此外，幼儿中CD45RO +记忆CD4 +和CD8 + T细胞的频率低于成人，并且观察到CD45RO +记忆CD4 + T细胞与IL-22 + CD4 + T细胞、Th1、Th17之间存在显著相关性。
Th22亚群存在于幼儿外周血中。与成人相比，幼儿外周血中IL-22 + CD4 + T细胞以及Th1、Th17、Th2和Tc1亚群的频率较低。
