The microbiome contributes to the development and maturation of the immune system. In response to commensal bacteria, intestinal CD4 + T lymphocytes differentiate into functional subtypes with regulatory or effector functions. The development of small intestine intraepithelial lymphocytes that coexpress CD4 and CD8αα homodimers (CD4IELs) depends on the microbiota. However, the identity of the microbial antigens recognized by CD4 + T cells that can differentiate into CD4IELs remains unknown. We identified β-hexosaminidase, a conserved enzyme across commensals of the Bacteroidetes phylum, as a driver of CD4IEL differentiation. In a mouse model of colitis, β-hexosaminidase–specific lymphocytes protected against intestinal inflammation. Thus, T cells of a single specificity can recognize a variety of abundant commensals and elicit a regulatory immune response at the intestinal mucosa.

中文翻译：

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保守的拟杆菌抗原诱导抗炎肠道 T 淋巴细胞

微生物组有助于免疫系统的发育和成熟。响应共生细菌，肠道 CD4+T 淋巴细胞分化为具有调节或效应功能的功能亚型。共表达 CD4 和 CD8αα 同二聚体 (CD4IEL) 的小肠上皮内淋巴细胞的发育取决于微生物群。然而，CD4 识别的微生物抗原的身份+能够分化为 CD4IEL 的 T 细胞仍然未知。我们确定了 β-己糖胺酶（拟杆菌门共生体中的一种保守酶）作为 CD4IEL 分化的驱动因素。在结肠炎小鼠模型中，β-己糖胺酶特异性淋巴细胞可防止肠道炎症。因此，单一特异性的T细胞可以识别多种丰富的共生体并在肠粘膜处引发调节性免疫反应。