Enterovirus 71 (EV71) is a major pathogen that causes hand, foot and mouth disease (HFMD), which is a life threatening disease in certain children. The pathogenesis of EV71-caused HFMD is poorly defined due to the lack of simple and robust animal models with severe phenotypes that recapitulate symptoms observed in humans. Here, we generated the infectious clone of a clinical isolate from a severe HFMD patient. Virus rescued from the cDNA clone was infectious in cell lines. When administrated intraperitoneally to neonatal ICR, BALB/c and C57 immune competent mice at a dosage of1.4 × 104 pfu per mouse, the virus caused weight loss, paralysis and death in the infected mice after 4-5 days of infection. In the infected mice, detectable viral replication was detected in various tissues such as heart, liver, brain, lung, kidney, small intestine, leg skeletal muscle and medulla oblongata. The histology of the infected mice included massive myolysis, glomerular atrophy, villous blunting in small intestine, widened alveolar septum, diminished alveolar spaces and lymphocytes infiltration into the lung. By using the UV-inactivated virus as a control, we elucidated that the virus first amplified in the leg skeletal muscle tissue and the muscle tissue served as a primary viral replication site. In summary, we generated a stable EV71 infectious clone that is capable of infecting neonatal immune competent mice without adaptive mutations and provide a simple, valuable animal model for the studies of EV71pathogenesis and therapy.

中文翻译：

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肠病毒71（EV71）的感染性克隆，能够感染没有适应性突变的新生儿免疫功能小鼠。

肠病毒71（EV71）是导致手足口病（HFMD）的主要病原体，手足口病是某些儿童的致命性疾病。EV71引起的手足口病的发病机制定义不清，原因是缺乏简单且健壮的动物模型，其具有重现人类症状的表型。在这里，我们从一名重度手足口病患者中产生了临床分离株的感染性克隆。从cDNA克隆中拯救出来的病毒在细胞系中具有传染性。当以每只小鼠1.4×104 pfu的剂量腹膜内给新生儿ICR，BALB / c和C57免疫能力强的小鼠给药时，该病毒在感染4-5天后会引起体重减轻，瘫痪和死亡。在受感染的小鼠中，在心脏，肝脏，大脑，肺，肾脏，小肠等各种组织中检测到可检测的病毒复制，腿部骨骼肌和延髓。感染小鼠的组织学包括大量肌溶解，肾小球萎缩，小肠绒毛变钝，肺泡间隔增宽，肺泡间隙减少和淋巴细胞向肺部浸润。通过使用紫外线灭活的病毒作为对照，我们阐明了该病毒首先在腿部骨骼肌组织中扩增，并且该肌肉组织充当了主要的病毒复制位点。总而言之，我们产生了一个稳定的EV71感染性克隆，该克隆能够感染没有适应性突变的新生儿免疫功能小鼠，并为EV71发病机理和治疗研究提供了一种简单而有价值的动物模型。肺泡间隔增宽，肺泡间隙减少和淋巴细胞向肺部浸润。通过使用紫外线灭活的病毒作为对照，我们阐明了该病毒首先在腿部骨骼肌组织中扩增，并且该肌肉组织充当了主要的病毒复制位点。总而言之，我们生成了一个稳定的EV71感染性克隆，该克隆能够感染没有适应性突变的新生儿免疫功能小鼠，并为EV71发病机理和治疗研究提供了一种简单而有价值的动物模型。肺泡间隔增宽，肺泡间隙减少和淋巴细胞向肺部浸润。通过使用紫外线灭活的病毒作为对照，我们阐明了该病毒首先在腿部骨骼肌组织中扩增，并且该肌肉组织充当了主要的病毒复制位点。总而言之，我们生成了一个稳定的EV71感染性克隆，该克隆能够感染没有适应性突变的新生儿免疫功能小鼠，并为EV71发病机理和治疗研究提供了一种简单而有价值的动物模型。