Harnessing the microbiome to benefit human health requires an initial step in determining the identity and function of causative microorganisms that affect specific host physiological functions. We show a functional screen of the bacterial microbiota from mice with low intestinal immunoglobulin A (IgA) levels; we identified a Gram-negative bacterium, proposed as Tomasiella immunophila , that induces and degrades IgA in the mouse intestine. Mice harboring T. immunophila are susceptible to infections and show poor mucosal repair. T. immunophila is auxotrophic for the bacterial cell wall amino sugar N-acetylmuramic acid. It delivers immunoglobulin-degrading proteases into outer membrane vesicles that preferentially degrade rodent antibodies with kappa but not lambda light chains. This work indicates a role for symbionts in immunodeficiency, which might be applicable to human disease.

中文翻译：

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宿主适应的营养缺陷型肠道共生体诱导粘膜免疫缺陷


利用微生物组造福人类健康，需要第一步来确定影响特定宿主生理功能的致病微生物的身份和功能。我们展示了肠道免疫球蛋白 A （IgA） 水平低的小鼠细菌微生物群的功能筛选;我们鉴定了一种革兰氏阴性细菌，被提出为 嗜免疫托马西菌 ，它在小鼠肠道中诱导和降解 IgA。携带嗜免疫 T 的小鼠易受感染，并且粘膜修复不良。T. immunophila 对细菌细胞壁氨基糖 N-乙酰胞壁酸具有营养缺陷型。它将免疫球蛋白降解蛋白酶递送到外膜囊泡中，这些囊泡优先降解具有 κ 轻链的啮齿动物抗体，而不是 lambda 轻链。这项工作表明共生体在免疫缺陷中的作用，这可能适用于人类疾病。