小柯机器人

美国克利夫兰诊所Thaddeus S. Stappenbeck团队发现，一种宿主适应性的缺乏营养的肠道共生菌诱导黏膜免疫缺陷。2024年9月27日出版的《科学》发表了这项成果。

研究人员展示了对肠道免疫球蛋白A（IgA）水平低的鼠类细菌微生物群的功能筛选；并识别出一种革兰氏阴性菌，命名为Tomasiella immunophila，该菌在小鼠肠道中诱导并降解IgA。携带T. immunophila的小鼠易感染，且黏膜修复不良。

T. immunophila对细菌细胞壁氨基糖N-乙酰葡萄糖胺缺乏合成能力。它通过外膜囊泡输送降解免疫球蛋白的蛋白酶， 偏好地降解含有kappa而非lambda轻链的啮齿动物抗体。这项工作表明了共生菌在免疫缺陷中的作用，可能与人类疾病相关。

研究人员表示，利用微生物组促进人类健康的首要步骤是确定影响特定宿主生理功能的致病微生物的身份和功能。

附：英文原文

Title: A host-adapted auxotrophic gut symbiont induces mucosal immunodeficiency

Author: Qiuhe Lu, Thomas C. A. Hitch, Julie Y. Zhou, Mohammed Dwidar, Naseer Sangwan, Dylan Lawrence, Lila S. Nolan, Scott T. Espenschied, Kevin P. Newhall, Yi Han, Paul E. Karell, Vanessa Salazar, Megan T. Baldridge, Thomas Clavel, Thaddeus S. Stappenbeck

Issue&Volume: 2024-09-27

Abstract: 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.

DOI: adk2536

Source: https://www.science.org/doi/10.1126/science.adk2536