Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a foodborne pathogen which causes illness in humans. Ruminants are the main reservoirs and EHEC predominantly colonizes the epithelium of the recto-anal junction of cattle. Immunosuppression by EHEC promotes re-infection of cattle. However, bovine lactoferrin (bLF) apparently can overrule the immunosuppression by inducing EHEC-specific IgA responses at the mucosal site. The IgA responses are significantly correlated with reduced EHEC shedding and the absence of colonization at the rectal mucosa following re-infection. Therefore, to examine the interaction between bLF and bovine rectal epithelial cells, we first developed a method to establish a primary cell culture of epithelial cells of the rectum of cattle. Furthermore, we used LC-MS/MS to demonstrate the presence of secreted lactoferrin in bovine milk and the absence of a "delta" isoform which is known to translocate to the nucleus of cells. Nevertheless, lactoferrin derived from bovine milk was internalized by rectal epithelial cells and translocated to the nuclei. Moreover, nuclear translocation of bLF was significantly enhanced when the epithelial cells were inoculated with EHEC, as demonstrated by confocal fluorescence microscopy and confirmed by Raman microscopy and 3D imaging.

中文翻译：

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乳铁蛋白在大肠杆菌O157：H7存在下易位至牛直肠上皮细胞核。

肠出血性大肠杆菌（EHEC）O157：H7是一种食源性病原体，可导致人类疾病。反刍动物是主要的水库，EHEC主要定居在牛的直肠-肛门交界处的上皮细胞上。EHEC的免疫抑制作用可促进牛的再感染。但是，牛乳铁蛋白（bLF）显然可以通过在粘膜部位诱导EHEC特异性IgA反应来推翻免疫抑制作用。IgA反应与EHEC脱落减少和再感染后直肠黏膜上无定植显着相关。因此，为了检查bLF与牛直肠上皮细胞之间的相互作用，我们首先开发了一种建立牛直肠上皮细胞原代细胞培养的方法。此外，我们使用LC-MS / MS证明了牛乳中分泌的乳铁蛋白的存在，以及不存在已知易位至细胞核的“δ”同种型。然而，源自牛乳的乳铁蛋白被直肠上皮细胞内化并转移至细胞核。此外，如通过共聚焦荧光显微镜证实并通过拉曼显微镜和3D成像证实，当用EHEC接种上皮细胞时，bLF的核转位显着增强。