Ji Xingzhao, Tan Xiaoluo, Hou Xuexin, Si Chenchen, Xu Shuai, Tang Lu, Yuan Xiuqin, Li Zhenjun
State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention Beijing, China.
Office of Emergency Response, Chenzhou Center for Disease Control and PreventionChenzhou, China; School of Public Health, University of South ChinaHengyang, China.
Front Microbiol. 2017 Feb 22;8:281. doi: 10.3389/fmicb.2017.00281. eCollection 2017.
Bacterial mammalian cell entry (Mce) proteins have been implicated in pathogen invasion of mammalian host cells. The aim of this study was to examine the invasion-conferring ability of operon-encoded proteins, expression of Mce1E in cells from infected mice and rabbits, and Mce1E immunogenicity. was cloned into pet30a(+) vectors, expressed in , and purified. Invasion assays, transmission electron microscopy (TEM), immunoblots, and enzyme-linked immunosorbent assay (ELISA) detection of cytokines were conducted. TEM confirmed the invasion of HeLa cells by Mce1E-coated beads. The antigenicity of -expressed recombinant Mce1E was confirmed in immunoblots with sera from -infected mouse and rabbit sera. Co-incubation of Mce1E with splenocytes of -infected mice demonstrated upregulation of interferon (IFN-γ), but not interleukin (IL)-4 or IL-10, in the cultural supernatant. These findings demonstrate that Mce1E may facilitate interactions with and invasion of mammalian cells. Notably, Mce1E are expressed and elicited antibody responses in mice and rabbits during infection. Besides, it may play a role in cell-mediated immune reactions and cause host inflammation responses to infection.
细菌哺乳动物细胞进入（Mce）蛋白与病原体入侵哺乳动物宿主细胞有关。本研究的目的是检测操纵子编码蛋白的侵袭赋予能力、感染小鼠和兔子细胞中Mce1E的表达以及Mce1E的免疫原性。将其克隆到pet30a(+)载体中，在大肠杆菌中表达并纯化。进行了侵袭试验、透射电子显微镜（TEM）、免疫印迹以及细胞因子的酶联免疫吸附测定（ELISA）检测。TEM证实了包被Mce1E的珠子对HeLa细胞的侵袭。用感染小鼠和兔子血清进行的免疫印迹证实了表达的重组Mce1E的抗原性。Mce1E与感染小鼠的脾细胞共同孵育表明，培养上清液中干扰素（IFN-γ）上调，但白细胞介素（IL）-4或IL-10未上调。这些发现表明，Mce1E可能促进与哺乳动物细胞的相互作用和入侵。值得注意的是，Mce1E在感染期间在小鼠和兔子中表达并引发抗体反应。此外，它可能在细胞介导的免疫反应中起作用，并导致宿主对感染的炎症反应。
