母源性抗体抗病毒性疾病研究进展

母源性抗体能够保护新生儿和婴幼儿早期抵御多种病毒的感染,但它也严重抑制婴幼儿疫苗接种后主动免疫应答的建立．母源性抗体降至失去有效保护作用但又足以抑制婴幼儿对疫苗的免疫应答这样一段时期是婴幼儿病毒性疾病的易感期．目前有多种解释试图阐明母源性抗体抑制作用的机理．综述了近年来母源性抗体及其在抗病毒性疾病中的相关研究结果,主要从母源性抗体的传递途径、母源性抗体保护新生儿和婴幼儿早期抗病毒感染、母源性抗体对婴幼儿疫苗接种后主动免疫应答的影响以及母源性抗体抑制婴幼儿主动免疫应答机理假说等方面进行阐述．     

Ebola virus entry requires the host-programmed recognition of an intracellular receptor

Ebola and Marburg filoviruses cause deadly outbreaks of haemorrhagic fever. Despite considerable efforts, no essential cellular receptors for filovirus entry have been identified. We showed previously that Niemann-Pick C1 (NPC1), a lysosomal cholesterol transporter, is required for filovirus entry. Here, we demonstrate that NPC1 is a critical filovirus receptor. Human NPC1 fulfills a cardinal property of viral receptors: it confers susceptibility to filovirus infection when expressed in non-permissive reptilian cells. The second luminal domain of NPC1 binds directly and specifically to the viral glycoprotein, GP, and a synthetic single-pass membrane protein containing this domain has viral receptor activity. Purified NPC1 binds only to a cleaved form of GP that is generated within cells during entry, and only viruses containing cleaved GP can utilize a receptor retargeted to the cell surface. Our findings support a model in which GP cleavage by endosomal cysteine proteases unmasks the binding site for NPC1, and GP-NPC1 engagement within lysosomes promotes a late step in entry proximal to viral escape into the host cytoplasm. NPC1 is the first known viral receptor that recognizes its ligand within an intracellular compartment and not at the plasma membrane.     

The effect of inbreeding on defence against multiple enemies in Datura stramonium

The ability of plants to respond to natural enemies might depend on the availability of genetic variation for the optimal phenotypic expression of defence. Selfing can affect the distribution of genetic variability of plant fitness, resistance and tolerance to herbivores and pathogens. The hypothesis of inbreeding depression influencing plant defence predicts that inbreeding would reduce resistance and tolerance to damage by natural enemies relative to outcrossing. In a field experiment entailing experimentally produced inbred and outcrossed progenies, we assessed the effects of one generation of selfing on Datura stramonium resistance and tolerance to three types of natural enemies, herbivores, weevils and a virus. We also examined the effect of damage on relative growth rate (RGR), flower, fruit, and seed production in inbred and outcrossed plants. Inbreeding significantly reduced plant defence to natural enemies with an increase of 4% in herbivore damage and 8% in viral infection. These results indicate inbreeding depression in total resistance. Herbivory increased 10% inbreeding depression in seed number, but viral damage caused inbred and outcrossed plants to have similar seed production. Inbreeding and outcrossing effects on fitness components were highly variable among families, implying that different types or numbers of recessive deleterious alleles segregate following inbreeding in D. stramonium. Although inbreeding did not equally alter all the interactions, our findings indicate that inbreeding reduced plant defence to herbivores and pathogens in D. stramonium.     

甲型流感病毒合并肺部感染与非病毒性肺部感染的表现及治疗分析

目的:通过与非病毒性肺部感染对比,分析甲型流感病毒合并肺部感染患者的常见临床实验检查及治疗效果,为经验性治疗甲型流感病毒提供一定依据。方法:选择2017年11月至2018年4月期间在我科接受治疗的已确诊存在甲型流病毒合并肺部感染(A组)及非病毒性肺感染(B组)各25例,对于确诊的甲型流感患者给予奥司他韦抗病毒治疗一周外,两组均正常给予常规抗感染治疗,对比两组患者的炎症指标白细胞计数、中性粒细胞比例、C-反应蛋白及治疗天数、住院天数、症状消失时间、不良反应发生率。结果:两组患者的CT检查表现无统计学差异(P0.05),A组患者的白细胞计数水平明显低于B组,差异有统计学意义(P0.05),而两组患者的中性粒细胞比例及C反应蛋白水平差异无统计学意义(P0.05)。两组患者的治疗天数及住院天数差异均无统计学意义(P0.05)。两组患者在体温恢复正常时间、咳嗽消失时间、肺部湿罗音消失时间、气促消失时间等比较差异无统计学意义(P0.05)。A组不良反应发生率为16.00%(4/25),B组不良反应发生率为12.00%(3/25),组间差异无统计学意义(P0.05)。结论:甲型病毒性肺部感染常表现为血常规未见异常,常伴发不同程度炎症反应,除常规抗感染治疗外,口服抗病毒药物奥司他韦可促进疾病转归。     

RNA干扰与抗病毒感染

RNA干扰(RNAi)是由小干扰RNA(siRNA)引发的生物细胞内同源基因的转录后基因沉默(PTGS)现象,是一种古老的生物抵抗外在感染的防御机制。RNAi因其在维持基因组稳定、调控基因表达和保护基因组免受外源核酸侵入等方面发挥的重要作用,已被广泛用于探索基因功能、基因治疗和新药的研发。外源导入siRNA引发的RNAi可以特异性抑制病毒的复制与感染,为抗病毒感染治疗开辟了一条新的途径。     

A reproducible microanalytical method for the detection of specific RNA sequences by dot-blot hybridization

A rapid, microanalytical procedure for the reproducible isolation of RNA from small cultured cell samples and application to dot-blot hybridization is described. The procedure employs guanidine hydrochloride solubilization of whole cells, disruption by syringing, and selective precipitation of RNA with ethanol. The method can be performed in a single tissue culture tube and obviates the need for removal of nuclei or for organic solvent extractions. Recovery of RNA from small cell samples (10(6) cells) is 51%, while 97% of the DNA and 99% of the protein are eliminated by the procedure. Detection of specific RNA by dot-blot hybridization using a labeled probe demonstrates high reproducibility of recovered RNA and lack of "masking" with up to a 10-fold excess of starting cell material. Applicability of the procedure to detection of virus-specific RNA in cells persistently infected with mouse hepatitis virus is described.     

The role of nutrition in viral disease

Malnutrition has been associated with a decrease in immune function. Impairment of immune function may lead to increased susceptibility to infection with viruses. Although there are many studies documenting the effect of host nutritional status on immune functions, fewer studies have examined the effect of host nutritional status on viral pathogenesis. This review examines the relationship between viral infection and the nutritional status of the host, and documents that not only can the nutritional status of the host affect immune function, but can have profound effects on the virus itself. One mechanism by which nutritional status affects the virulence of the viral pathogen involves selection for virulent viral genotypes. Other mechanisms remain to be elucidated.     

战“疫”时期“病毒生物学”课程的教学调整与思考

2020年春天,全球进入对抗新型冠状病毒(Severe Acute Respiratory Syndrome Coronavirus 2,SARS-CoV-2)感染引起的\"新冠\"肺炎(Coronavirus Disease,COVID-19)疫情的斗争中。为了适应全民抗\"疫\"的新形势,引导学生理性地、科学地认识此次病毒疫情,\"病毒生物学\"课程的教学从内容到形式也进行了同步设计与微调。除了将教学模式由线下教学变成线上直播,本课程结合疫情发展情况在学期初进行COVID-19的专题讲座,以及通过\"COVID-19-5 min\"形式每次上课进行疫情周报解读,分析国内外疫情并传授病毒流行病学相关知识。另外,对\"病毒生物学\"的教学计划和教学内容做了适当微调,更多关注病毒性传染疾病发展和相关科学研究的进展。通过对在线教学从教学模式、教学过程和教学内容的设计和调整,强化教学效果的反馈和改善,引导学生不信谣、不传谣,帮助学生加强对新型冠状病毒(SARS-CoV-2)及疫情的科学认识。通过教学内容和教学形式的调整以及病毒疫情相关知识点的强化,激发了生物学专业学生对病毒学、流行病学及公共卫生健康等问题的关注。     

丙型肝炎病毒感染性细胞模型的研究进展

丙型肝炎病毒（HCV）是造成慢性肝炎,肝硬化及肝癌的重要原因之一,目前全球约有1.7亿人感染HCV。然而缺乏有效的HCV感染模型,严重阻碍了对HCV致病机制的认识。最近几年以JFH1株和Huh-7细胞系为基础,通过对不同病毒株基因组的重组和细胞系的优化,进一步提高其感染能力,在HCV感染系统的建立上取得了突破性进展。我们简要综述近几年在HCV感染细胞模型方面取得的进展。     

丙型肝炎病毒（HCV）实验性疫苗的研究进展

丙型肝炎病毒是引起输血相关肝炎及慢性肝炎、肝硬化、肝癌的主要病原,目前尚无有效的治疗与预防手段。本文将综述HCV感染所引起的机体免疫应答及近年来实验性疫苗（主要是DNA疫苗、病毒载体疫苗及联合疫苗）的研究进展。     

Systemic Bacterial Infection and Immune Defense Phenotypes in Drosophila Melanogaster

The fruit fly Drosophila melanogaster is one of the premier model organisms for studying the function and evolution of immune defense. Many aspects of innate immunity are conserved between insects and mammals, and since Drosophila can readily be genetically and experimentally manipulated, they are powerful for studying immune system function and the physiological consequences of disease. The procedure demonstrated here allows infection of flies by introduction of bacteria directly into the body cavity, bypassing epithelial barriers and more passive forms of defense and allowing focus on systemic infection. The procedure includes protocols for the measuring rates of host mortality, systemic pathogen load, and degree of induction of the host immune system. This infection procedure is inexpensive, robust and quantitatively repeatable, and can be used in studies of functional genetics, evolutionary life history, and physiology.     

Spontaneous hepatitis C viral clearance and hepatitis C chronic infection are associated with distinct cytokine profiles in Mexican patients

The mechanisms related to the spontaneous clearance of hepatitis C virus (HCV) havebeen primarily studied in regions where the infection is endemic. Results of priorstudies have been extrapolated to populations with low endemicity, such as Mexico.Herein, we determined the cytokine profiles in serum samples from Mexican patientswho spontaneously cleared HCV and patients chronically infected with HCV genotype 1a.Chronic HCV-infected patients displayed increased interleukin (IL)-8 and regulatedupon activation, normal T-cell expressed and secreted (CCL-5) secretion, whereaspatients who spontaneously cleared HCV showed augmented levels of IL-1 alpha, tumournecrosis factor-alpha, transforming growth factor-beta, monocyte chemoattractantprotein-2 (CCL-8), IL-13 and IL-15. Our study suggeststhat cytokine profiles maypredict disease outcome during HCV infection.