Host Immune Selection of Rumen Bacteria through Salivary Secretory IgA.
Host Immune Selection of Rumen Bacteria through Salivary Secretory IgA.
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DOI：
10.3389/fmicb.2017.00848
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发表时间：
2017
影响因子：
5.2
通讯作者：
Willing BP
中科院分区：
文献类型：
--
作者：
Fouhse JM;Smiegielski L;Tuplin M;Guan LL;Willing BP
瘤胃微生物组对牛的高效生产是不可或缺的，并且表现出很强的宿主特异性，但对于宿主因素影响瘤胃微生物组成知之甚少。分泌性免疫球蛋白A （SIgA）在唾液中大量产生，可以覆盖肠道内的共生微生物和致病微生物，并呈现出一种合理的宿主特异性机制。然而，唾液SIgA在反刍动物共生菌选择中的作用仍然难以捉摸。本研究的主要目的是建立一种免疫亲和台式方法来分离SIgA标记的微生物群，并确定唾液SIgA是否优先结合选定的细菌。我们假设siga标记的细菌与总细菌不同，从而支持共生细菌选择的潜在宿主衍生机制。整个瘤胃（n = 9）和口腔分泌物样本（n = 10）与抗分泌IgA抗体结合的磁珠孵育，以丰富siga标记的微生物群。从口腔分泌物、整个瘤胃、siga标记的口腔分泌物和siga标记的瘤胃中分离微生物DNA，对16S rDNA基因V1-V3区进行扩增子测序。欧几里得距离非参数多维标度图显示，全瘤胃和口腔分泌物细菌组成差异显著（P < 0.05）。瘤胃和口腔分泌物中siga标记的微生物群中拟杆菌门、放线菌门、纤维杆菌门、候选门TM7和Tenericutes的丰度相似，并且紧密聚集。siga标记的口腔分泌物微生物群的组成与整个瘤胃微生物群的组成更相似，这是由于瘤胃细菌（Lachnospiraceae）的富集和口腔分类群（Streptococcus, Rothia, neisseraceae, Lactobacillales）的减少。综上所述，siga标记的口腔分泌物微生物群与整个瘤胃微生物群的相似性增加，表明唾液siga涂层可能是影响共生定植的一种宿主来源机制。进一步的研究，探索不同动物之间抗体亲和力的变化作为微生物组成的驱动因素是必要的。
The rumen microbiome is integral to efficient production in cattle and shows strong host specificity, yet little is known about what host factors shape rumen microbial composition. Secretory immunoglobulin A (SIgA) is produced in large amounts in the saliva, can coat both commensal and pathogenic microbes within the gut, and presents a plausible mechanism of host specificity. However, the role salivary SIgA plays in commensal bacteria selection in ruminants remains elusive. The main objectives of this study were to develop an immuno-affinity benchtop method to isolate SIgA-tagged microbiota and to determine if salivary SIgA preferentially binds selected bacteria. We hypothesized that SIgA-tagged bacteria would differ from total bacteria, thus supporting a potential host-derived mechanism in commensal bacterial selection. Whole rumen (n = 9) and oral secretion samples (n = 10) were incubated with magnetic beads conjugated with anti-secretory IgA antibodies to enrich SIgA-tagged microbiota. Microbial DNA from the oral secretion, whole rumen, SIgA-tagged oral secretion, and SIgA-tagged rumen was isolated for amplicon sequencing of V1–V3 region of 16S rDNA genes. Whole rumen and oral secretion had distinctive (P < 0.05) bacterial compositions indicated by the non-parametric multidimensional scaling plot using Euclidean distance metrics. The SIgA-tagged microbiota from rumen and oral secretion had similar abundance of Bacteroidetes, Actinobacteria, Fibrobacter, candidate phyla TM7, and Tenericutes and are clustered tightly. Composition of SIgA-tagged oral secretion microbiota was more similar to whole rumen microbiota than whole oral secretion due to enrichment of rumen bacteria (Lachnospiraceae) and depletion of oral taxa (Streptococcus, Rothia, Neisseriaceae, and Lactobacillales). In conclusion, SIgA-tagged oral secretion microbiota had an increased resemblance to whole rumen microbiota, suggesting salivary SIgA-coating may be one host-derived mechanism impacting commensal colonization. Further studies, to explore the variations in antibody affinity between different animals as a driver of microbial composition are warranted.