A Soluble Immune Effector Binds Both Fungi and Bacteria via Separate Functional Domains
A Soluble Immune Effector Binds Both Fungi and Bacteria via Separate Functional Domains
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DOI：
10.3389/fimmu.2019.00369
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发表时间：
2019-03
影响因子：
7.3
通讯作者：
A. Liberti;J. Cannon;G. Litman;Larry J Dishaw
中科院分区：
文献类型：
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作者：
A. Liberti;J. Cannon;G. Litman;Larry J Dishaw
动物的肠道微生物组由多种微生物组成，包括原核生物和真核生物。这些居民之间发生复杂的相互作用，以及与宿主的免疫系统，并深刻影响宿主及其微生物共生体的整体健康。尽管宿主调节其肠道微生物组非常重要，但动物产生具有直接影响多微生物相互作用能力的免疫相关分子的程度仍不清楚。尾索动物，Ciona robusta，是一种模式生物，已适应宿主/微生物组相互作用的实验研究。玻璃海鞘可变区几丁质结合蛋白（VCBPs）是由免疫球蛋白（IG）可变区和几丁质结合结构域（CBD）组成的先天性免疫效应物，在肠道中以高丰度表达。先前显示VCBP-C结合细菌并通过其IG结构域影响颗粒状变形细胞的吞噬作用和生物膜形成。我们在这里表明，CBD的VCBP-C独立地识别几丁质分子存在于细胞壁，孢子囊（孢子形成体），和孢子的一组不同的丝状真菌分离的玻璃海鞘肠道。据我们所知，这是第一次描述的分泌型免疫球蛋白含有免疫分子的能力，直接促进transkingdom相互作用，通过同时结合独立的结构域，并可能在调节肠道微生物组的建立，继承和稳态的广泛影响。
The gut microbiome of animals consists of diverse microorganisms that include both prokaryotes and eukaryotes. Complex interactions occur among these inhabitants, as well as with the immune system of the host, and profoundly influence the overall health of both the host and its microbial symbionts. Despite the enormous importance for the host to regulate its gut microbiome, the extent to which animals generate immune-related molecules with the capacity to directly influence polymicrobial interactions remains unclear. The urochordate, Ciona robusta, is a model organism that has been adapted to experimental studies of host/microbiome interactions. Ciona variable-region containing chitin-binding proteins (VCBPs) are innate immune effectors, composed of immunoglobulin (Ig) variable regions and a chitin-binding domain (CBD) and are expressed in high abundance in the gut. It was previously shown that VCBP-C binds bacteria and influences both phagocytosis by granular amoebocytes and biofilm formation via its Ig domains. We show here that the CBD of VCBP-C independently recognizes chitin molecules present in the cell walls, sporangia (spore-forming bodies), and spores of a diverse set of filamentous fungi isolated from the gut of Ciona. To our knowledge, this is the first description of a secreted Ig-containing immune molecule with the capacity to directly promote transkingdom interactions through simultaneous binding by independent structural domains and could have broad implications in modulating the establishment, succession, and homeostasis of gut microbiomes.