Non-pathogenic bacteria elicit a differential cytokine response by intestinal epithelial cell/leucocyte co-cultures
Non-pathogenic bacteria elicit a differential cytokine response by intestinal epithelial cell/leucocyte co-cultures
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作者：
Haller, D;Bode, C;Blum, S
背景和目的肠上皮细胞（IEC）被认为参与粘膜对细菌的防御和粘膜组织稳态的调节。IEC对细菌信号的反应性可能取决于与免疫活性细胞的相互作用。要解决的问题，是否非致病性细菌修改的免疫反应的肠上皮细胞，我们共同培养的肠上皮细胞样CaCO-2细胞与人血白细胞在不同的隔室transwell cultures. Methods-CaCO-2/PBMC共培养物刺激与非致病性细菌和肠致病性大肠杆菌。肿瘤坏死因子α的表达通过酶联免疫吸附试验研究了TNF-α、白细胞介素（IL）-1 β、IL-8、单核细胞趋化蛋白1（MCP-1）和IL-10的表达情况。结果-用非致病性大肠杆菌和清酒乳杆菌攻击CaCO-2细胞诱导IL-8，MCP-1，IL-1 β和TNF-α mRNA在存在潜在白细胞的情况下。白细胞致敏的CaCO-2细胞产生TNF-α和IL-1 β，而IL-10仅由人外周血单核细胞分泌。单独的CaCO-2细胞对细菌攻击保持低应答。肠道分离物约氏乳杆菌在白细胞致敏的CaCO-2细胞中诱导促炎细胞因子的潜力降低，但转化生长因子β mRNA增加。TNF-α被确定为参与细胞串扰的早期介质之一。在白细胞的存在下，区分激活的CaCO-2细胞之间观察到肠致病性大肠杆菌和非致病性bacteries.Conclusion-The差异识别的非致病性细菌的CaCO-2细胞需要潜在的白细胞的存在。这些结果加强了粘膜表面细菌信号传导依赖于细胞相互作用网络的假设。
Background and aim-Intestinal epithelial cells (IEC) are thought to participate in the mucosal defence against bacteria and in the regulation of mucosal tissue homeostasis. Reactivity of IEC to bacterial signals may depend on interactions with immunocompetent cells. To address the question of whether non-pathogenic bacteria modify the immune response of the intestinal epithelium, we co-cultivated enterocyte-like CaCO-2 cells with human blood leucocytes in separate compartments of transwell cultures.Methods-CaCO-2/PBMC co-cultures were stimulated with non-pathogenic bacteria and enteropathogenic Escherichia coli. Expression of tumour necrosis factor alpha (TNF-alpha), interleukin (IL)-1 beta, IL-8, monocyte chemoattracting protein 1 (MCP-1), and IL-10 was studied by enzyme linked immunosorbent assays (cytokine secretion) and by semiquantitative reverse transcription-polymerase chain reaction.Results-Challenge of CaCO-2 cells with non-pathogenic E coli and Lactobacillus sakei induced expression of IL-8, MCP-1, IL-1 beta, and TNF-alpha mRNA in the presence of underlying leucocytes. Leucocyte sensitised CaCO-2 cells produced TNF-alpha and IL-1 beta whereas IL-10 was exclusively secreted by human peripheral blood mononuclear cells. CaCO-2 cells alone remained hyporesponsive to the bacterial challenge. Lactobacillus johnsonii, an intestinal isolate, showed reduced potential to induce proinflammatory cytokines but increased transforming growth factor beta mRNA in leucocyte sensitised CaCO-2 cells. TNF-alpha was identified as one of the early mediators involved in cellular cross talk. In the presence of leucocytes, discriminative activation of CaCO-2 cells was observed between enteropathogenic E coli and non-pathogenic bacteria.Conclusion-The differential recognition of non-pathogenic bacteria by CaCO-2 cells required the presence of underlying leucocytes. These results strengthen the hypothesis that bacterial signalling at the mucosal surface is dependent on a network of cellular interactions.