Key Laboratory of Comprehensive Utilization of Advantage Plants Resources in Hunan South, College of Chemistry and Bioengineering, Hunan University of Science and Engineering, Yongzhou, Hunan, China.
State Key Laboratory of Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Zhejiang, Hangzhou, China.
Microb Ecol. 2020 May;79(4):1021-1033. doi: 10.1007/s00248-019-01441-4. Epub 2019 Nov 14.
Segmented filamentous bacteria (SFB) are well known for their functions in the immunoregulation of hosts including the promotion of Th17 cell differentiation, B cell maturation, and immune system development. However, most analyses of SFB have focused on animal models, and thus, investigation of SFB prevalence in humans and their roles in human immunoregulation and health is needed. Although little is known overall of SFB prevalence in humans, they are characteristically abundant in animals during weaning. In this study, SFB-like bacteria were detected in ileal lavage samples from human children that were aged between 1 to 17 years old by scanning electron microscopy (SEM) analysis, and their insertion into the mucosa was also observed. In addition, the expression of SFB flagellin at the human bacterial interface was observed by immunohistochemistry (IHC) and western blot. Moreover, two pairs of primers specific for SFB, but targeting different genes, were used to detect SFB in human intestinal lavage samples. These analyses indicated that SFB were present in over 50% of patient ileal samples independent of age. High-throughput gene sequencing indicated that different SFB strains were detected among samples. Between nine and 23 SFB flagellin gene operational taxonomic units were identified. In addition to evaluating the prevalence of SFB in human samples, correlations between SFB presence and chief complaints of clinical symptoms were evaluated, as well as the relationship between SFB and patient serum immunoglobulin concentrations. SFB prevalence was significantly higher in hematochezia patients (68%) than in abdominal pain (56.10%) and diarrhea (43.75%) patients. Furthermore, the concentrations of serum IgA, IgM, and IgE, were similar between SFB-positive and SFB-negative patient groups, although IgG concentrations were significantly higher in the SFB-negative group.
分段丝状菌 (SFB) 以其在宿主免疫调节中的功能而闻名，包括促进 Th17 细胞分化、B 细胞成熟和免疫系统发育。然而，大多数对 SFB 的分析都集中在动物模型上，因此需要研究 SFB 在人类中的流行情况及其在人类免疫调节和健康中的作用。尽管总体而言，人们对 SFB 在人类中的流行情况知之甚少，但它们在动物断奶期间特征性地丰富。在这项研究中，通过扫描电子显微镜 (SEM) 分析检测到来自 1 至 17 岁人类儿童回肠灌洗样本中存在 SFB 样细菌，并且还观察到它们插入黏膜。此外，通过免疫组织化学 (IHC) 和 Western blot 观察到 SFB 鞭毛蛋白在人类细菌界面的表达。此外，使用两对针对 SFB 的特异性引物，但针对不同基因，检测人类肠道灌洗样本中的 SFB。这些分析表明，无论年龄大小，SFB 存在于超过 50%的患者回肠样本中。高通量基因测序表明，在样本中检测到不同的 SFB 菌株。鉴定出 9 到 23 个 SFB 鞭毛基因操作分类单位。除了评估 SFB 在人类样本中的流行率外，还评估了 SFB 存在与主要临床症状主诉之间的相关性，以及 SFB 与患者血清免疫球蛋白浓度之间的关系。便血患者 SFB 患病率 (68%)明显高于腹痛 (56.10%)和腹泻 (43.75%)患者。此外，SFB 阳性和 SFB 阴性患者组之间的血清 IgA、IgM 和 IgE 浓度相似，尽管 SFB 阴性组的 IgG 浓度明显更高。
