Siepert Bianca, Reinhardt Nicole, Kreuzer Susanne, Bondzio Angelika, Twardziok Sven, Brockmann Gudrun, Nöckler Karsten, Szabó Istvan, Janczyk Pawel, Pieper Robert, Tedin Karsten
Institute of Microbiology and Epizootics, Freie Universität Berlin, Robert-von-Ostertag-Str. 7-13, 14163 Berlin, Germany.
Institute of Microbiology and Epizootics, Freie Universität Berlin, Robert-von-Ostertag-Str. 7-13, 14163 Berlin, Germany; Institute of Anatomy, Medical Faculty, Otto-von-Guericke Universität, Leipziger Str. 44, 39120 Magdeburg, Germany.
Vet Immunol Immunopathol. 2014 Jan 15;157(1-2):65-77. doi: 10.1016/j.vetimm.2013.10.013. Epub 2013 Oct 28.
In a Salmonella challenge study of weaned piglets supplemented with the probiotic Enterococcus faecium NCIMB 10415 (SF68), we observed a delayed, post-infection proliferative response of purified blood mononuclear cell fractions towards Salmonella antigens. In order to clarify this observation, we examined the patterns of immune-associated gene expression in long-term feeding trials of both pre- and post-weaning piglets. Piglets supplemented with E. faecium NCIMB 10415 showed a post-weaning dysregulation in the expression patterns of both pro- and anti-inflammatory cytokine expression in intestinal tissues and spleen. Piglets of the supplemented group showed significantly reduced levels of IL-8, IL-10 and the co-stimulatory molecule CD86 mRNA expression in ileal Peyer's patches. The expression of CTLA4, an inhibitor of T-cell activation/proliferation, showed similar levels of expression in all tissues examined, particularly in ileal Peyer's patches post-weaning where IL-8, IL-10 and CD86 transcript levels were significantly reduced relative to control animals. Blood serum cytokine protein levels showed elevated TGFβ in pre-weaning piglets which, together with IL-6, may have suppressed IFNγ production in the probiotic-fed animals. In a second Salmonella challenge study, post-weaning, E. faecium-fed animals showed significantly elevated levels of IL-8 gene expression in mesenteric lymph nodes, but reduced levels in the spleen. At early times post-infection, the probiotic-fed group showed similar levels of IL-10, CD86 and CTLA4 mRNA expression as the control animals in intestinal Peyer's Patches, despite high relative levels of IL-8 expression in mesenteric lymph nodes. The sum of the observations suggests that supplementation of pre-weaning piglets with E. faecium affects intestinal immune-associated gene expression, which is aggravated post-weaning when the animals receive increased levels of the probiotic in feed. We suggest the post-weaning reductions in gene expression may delay the host response to infections, and provide pathogenic bacteria such as Salmonella with a "window of opportunity", leading to the increased bacterial loads and shedding observed in challenge trials. Possible mechanisms explaining these effects of E. faecium NCIMB 10415 are discussed.
在一项对补充了益生菌屎肠球菌NCIMB 10415（SF68）的断奶仔猪进行的沙门氏菌攻毒研究中，我们观察到纯化的血液单核细胞组分对沙门氏菌抗原的感染后增殖反应延迟。为了阐明这一观察结果，我们在断奶前和断奶后仔猪的长期饲养试验中检查了免疫相关基因的表达模式。补充了屎肠球菌NCIMB 10415的仔猪在断奶后肠道组织和脾脏中促炎和抗炎细胞因子表达模式均出现失调。补充组仔猪回肠派伊尔结中IL-8、IL-10和共刺激分子CD86 mRNA表达水平显著降低。T细胞活化/增殖抑制剂CTLA4的表达在所有检测组织中显示出相似的水平，尤其是在断奶后回肠派伊尔结中，相对于对照动物，IL-8、IL-10和CD86转录水平显著降低。血清细胞因子蛋白水平显示断奶前仔猪中TGFβ升高，这与IL-6一起可能抑制了益生菌喂养动物中IFNγ的产生。在第二项沙门氏菌攻毒研究中，断奶后，屎肠球菌喂养的动物肠系膜淋巴结中IL-8基因表达水平显著升高，但脾脏中的水平降低。在感染后的早期，尽管肠系膜淋巴结中IL-8表达相对水平较高，但益生菌喂养组在肠道派伊尔结中的IL-10、CD86和CTLA4 mRNA表达水平与对照动物相似。这些观察结果的总和表明，断奶前仔猪补充屎肠球菌会影响肠道免疫相关基因的表达，当动物在饲料中摄入增加水平的益生菌时，断奶后这种影响会加剧。我们认为断奶后基因表达的降低可能会延迟宿主对感染的反应，并为沙门氏菌等病原菌提供一个“机会窗口”，导致在攻毒试验中观察到的细菌载量增加和排菌。文中讨论了解释屎肠球菌NCIMB 10415这些作用的可能机制。
