Enterovirus 71 (EV71) is the predominant pathogen for severe hand, foot, and mouth disease (HFMD) in children younger than 5 years, and currently no effective drugs are available for EV71. Thus, there is an urgent need to develop new drugs for the control of EV71 infection. In this study, LJ04 was extracted from Laminaria japonica using diethylaminoethyl cellulose-52 with 0.4 mol/l NaCl as the eluent, and its virucidal activity was evaluated based on its cytopathic effects on a microplate. LJ04 is composed of fucose, galactose, and mannose and mainly showed good virucidal activity against EV71. The antiviral mechanisms of LJ04 were the direct inactivation of the virus, the blockage of virus binding, disruptions to viral entry, and weak inhibitory activity against the nonstructural protein 3C. The two most important findings from this study were that LJ04 inhibited EV71 proliferation in HM1900 cells, which are a human microglia cell line, and that LJ04 can directly inactivate EV71 within 2 hr at 37°C. This study demonstrates for the first time the ability of a polysaccharide from L. japonica to inhibit viral and 3C activity; importantly, the inhibition of 3C might have a minor effect on the antiviral effect of LJ04. Consequently, our results identify LJ04 as a potential drug candidate for the control of severe EV71 infection in clinical settings.

中文翻译：

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酸性多糖对肠道病毒71的体外杀菌活性和抗病毒机制。

肠病毒71（EV71）是5岁以下儿童严重手足口病（HFMD）的主要病原体，目前尚无有效的药物可用于EV71。因此，迫切需要开发用于控制EV71感染的新药。在这项研究中，LJ04是从日本海带中提取的，使用0.4 mol / l NaCl的二乙基氨基乙基纤维素-52作为洗脱液，并根据其对微孔板的细胞杀伤作用来评估其杀病毒活性。LJ04由岩藻糖，半乳糖和甘露糖组成，主要表现出对EV71的良好杀病毒活性。LJ04的抗病毒机制是病毒的直接灭活，病毒结合的阻断，病毒进入的破坏以及对非结构蛋白3C的弱抑制活性。这项研究的两个最重要的发现是LJ04抑制EV1900在人小胶质细胞系HM1900细胞中的增殖，并且LJ04可以在37°C下2小时内直接灭活EV71。这项研究首次证明了来自日本粳稻的多糖抑制病毒和3C活性的能力。重要的是，抑制3C可能对LJ04的抗病毒作用影响较小。因此，我们的结果确定LJ04是在临床环境中控制严重EV71感染的潜在候选药物。3C的抑制可能对LJ04的抗病毒作用影响较小。因此，我们的结果确定LJ04是在临床环境中控制严重EV71感染的潜在候选药物。3C的抑制可能对LJ04的抗病毒作用影响较小。因此，我们的结果确定LJ04是在临床环境中控制严重EV71感染的潜在候选药物。