流行性出血热病毒对乳鼠致病特点的观察

本文观察了两株从病人体内新分离的流行性出血热(EHF)病毒114株和435株对乳鼠的致病特点,并在感染的乳鼠脑内找到了EHF病毒。免疫荧光检查发现,病毒抗原广泛存在于感染鼠的脑、肺、肝、肾等脏器。脑内和腹腔两条感染途径的比较发现,病毒抗原在上述脏器中的分布基本一致,但前者脑内的病毒感染滴度较后者高一个对数单位。对病毒的动态观察发现,EHF病毒首先在乳鼠腹腔感染6小时后的腹腔巨噬细胞(Mφ)中分离到、并持续阳性;病毒血症出现在感染后2天,随之在脑、肺、肝、肾和脾脏中查到。以上结果表明:EHF病毒对乳鼠具有广泛的嗜性,脑内感染途径能获得较高滴度的感染性病毒。提示EHF病毒在鼠mφ中增殖并携带至全身播散,可能是造成乳鼠全身性弥漫性感染的主要原因。     

乳鼠感染流行性出血热病毒的研究

用获自病人的流行性出血热(EHF)病毒H8205株感染Vero-E6细胞的培养液,感染1日龄小白鼠,自第3代起,感染鼠出现规律发病,潜伏期13～18天,个体瘦小,后肢麻痹,最后死亡。病理检查感染鼠脑有典型病毒性脑炎改变,免疫荧光及酶标抗体染色证实脏器中存在特异性抗原,血内有特异性抗体,感染鼠的血,尿及脏器悬液经Vero-E6细胞培养出病毒。电镜检查脑神经原细胞高尔基氏器内有病毒颗粒。实验结果说明1日龄小白鼠对流行性出血热病毒是敏感的,可以作为该病毒的实验动物模型。     

用流行性出血热单克隆抗体对我国不同地区出血热病毒株的抗原分析

从全国17个省市自治区收集了自病人及各种动物分离到的40株流行性出血热病毒(EHFV),用出血热病毒单克隆抗体(McAb)进行抗原分析,发现大多数省市分离的EHFV株能与MA25-1 McAb起反应,但湖北、湖南分离的EHFV不与之起反应,而该McAb对EHFVA9株抗原的滴度为1/2560。实验还发现,湖北省内长江以北地区分离的EHFV毒株Q25、J173。WP43和从江南地区分离的EHFV毒株A24和HA1018在抗原性上也有明显不同。     

流行性出血热病毒感染NIH裸鼠免疫组织化学研究

流行性出血热病毒（ＥｐｉｄｅｍｉｃＨｅｍｏｒｒｈａｇｉｃＦｅｖｅｒｖｉｒｕｓ,ＥＨＦＶ）感染ＮＩＨ裸鼠后,濒死状态取材,应用免疫组织化学方法（ＡＢＣ）检测各组织中的特异性病毒抗原。结果表明,ＮＩＨ裸鼠对ＥＨＦＶ感染敏感,感染后其脑、肺、肝、肾和心脏组织实质细胞浆内均可检出特异性抗原。     

流行性出血热患者皮肤组织内病毒抗原及免疫复合物检测与意义

应用常规病理、免疫病理及超微病理技术,对３３例流行性出血热（ＥＨＦ）患者皮肤活检标本的病理变化及病毒抗原、免疫复合物进行观察,同时与血清病毒抗原、抗体及循环免疫复合物检出情况进行比较。在２３例ＥＨＦ患者皮肤微血管内皮细胞中检出病毒抗原,部分组织中可同时检出免疫球蛋白及Ｃ３,少数组织仅能检出病毒抗原或免疫球蛋白。配对血清小也可检出ＥＨＦ病毒抗原、抗体及循环免疫复合物。组织及血清免疫复合物形成与血清补体Ｃ３水平下降有关,组织内肥大细胞脱颗粒与血清ＩｇＥ水平升高相关,提示多种变态反应参与了流行性出血热的发病机制。     

流行性出血热病毒血凝素抗原位点分析

用八株不同来源的流行性出血热(EHF)病毒的单克隆抗体(McAb),采用血凝抑制试验、反向间接血凝抑制试验、间接酶联免疫及阻断酶联免疫试验等,对两种方法(TE、SA)制备的血凝素抗原进行分析。根据A35、2A6McA5试验的结果,证实血凝素抗原中的核蛋白上存在有非构象依赖性的血凝结合位点;而另外5株McAb在血凝抑制活性方面,虽具有明显的株间交叉,但在反向间接血凝抑制试验、间接酶联免疫试验时则均为阴性,故认为其血凝结合位点位于病毒的膜蛋白,可能与G_2糖蛋白有关,为构象依赖性位点。有关4G6McAb,在阻断酶联免疫试验时,虽与A35、2A6一样具有较高的阻断率,但在反向间接血凝抑制试验、间接酶联免疫试验时明显有别于后二者,对其属性有待进一步确定。     

流行性出血热病毒核酸的提取

本文报告流行性出血热R22和A9株病毒培养,同位素标记及核酸提取的初步研究,並获得了该病毒核酸的3个片段即L、M、S、分子量分别约为:3.8、1.9和0.86×10~5道尔顿,不论用20～70％蔗糖密度梯度离心提纯的病毒,或用30％蔗糖垫层离心的粗制病毒,均获同样结果,但多数情况下,用蔗糖密度梯度离心时,除病毒峰外,还发现主要由细胞组份(即线粒体和核糖体等)组成的另一峰,并经常影响病毒RNA的提取,对如何获得纯净病毒及其核酸进行了讨论。     

Measurement of virulence of aeromonads using a suckling mouse model of infection

Abstract Virulent and avirulent strains of Aeromonas spp. were identified and virulence quantified using an animal model. Virulence was measured by determining a 50% lethal dose (LD₅₀) 43 h after oral administration of live bacteria. The LD₅₀ of virulent Aeromonas isolates ranged from log₁₀ 7.53 (mean) organisms to log₁₀ 8.88 (mean). Some isolates were avirulent in this model. Detection of cytotoxic activity in culture supernatants correlated with virulence (Fisher exact test, P = 0.0029). There was no correlation between LD₅₀ and the source of the isolate, β-haemolysis or lipopolysaccharide (LPS) banding profile on SDS-PAGE. In this animal model, virulence was multifactorial in that: (i) bacterial multiplication in the gut was associated with fatal infection; (ii) the increase in bacterial numbers in the gut of mice administered a lethal dose of bacteria was accompanied by accumulation of fluid; and (iii) there was evidence of extraintestinal spread of infection. Protection of suckling mice by rabbit antiserum to Aeromonas cell envelopes was observed.     

Dengue virus infection induces autophagy: an in vivo study

Background

We and others have reported that autophagy is induced by dengue viruses (DVs) in various cell lines, and that it plays a supportive role in DV replication. This study intended to clarify whether DV infection could induce autophagy in vivo. Furthermore, the effect of DV induced autophagy on viral replication and DV-related pathogenesis was investigated.

Results and conclusions

The physiopathological parameters were evaluated after DV2 was intracranially injected into 6-day-old ICR suckling mice. Autophagy-related markers were monitored by immunohistochemical/immunofluorescent staining and Western blotting. Double-membrane autophagic vesicles were investigated by transmission-electron-microscopy. DV non-structural-protein-1 (NS1) expression (indicating DV infection) was detected in the cerebrum, medulla and midbrain of the infected mice. In these infected tissues, increased LC3 puncta formation, LC3-II expression, double-membrane autophagosome-like vesicles (autophagosome), amphisome, and decreased p62 accumulation were observed, indicating that DV2 induces the autophagic progression in vivo. Amphisome formation was demonstrated by colocalization of DV2-NS1 protein or LC3 puncta and mannose-6-phosphate receptor (MPR, endosome marker) in DV2-infected brain tissues. We further manipulated DV-induced autophagy by the inducer rapamycin and the inhibitor 3-methyladenine (3MA), which accordingly promoted or suppressed the disease symptoms and virus load in the brain of the infected mice.We demonstrated that DV2 infection of the suckling mice induces autophagy, which plays a promoting role in DV replication and pathogenesis.     

Enterovirus 71-induced autophagy increases viral replication and pathogenesis in a suckling mouse model

Background

We previously reported that Enterovirus 71 (EV71) infection activates autophagy, which promotes viral replication both in vitro and in vivo. In the present study we further investigated whether EV71 infection of neuronal SK-N-SH cells induces an autophagic flux. Furthermore, the effects of autophagy on EV71-related pathogenesis and viral load were evaluated after intracranial inoculation of mouse-adapted EV71 (MP4 strain) into 6-day-old ICR suckling mice.

Results

We demonstrated that in EV71-infected SK-N-SH cells, EV71 structural protein VP1 and nonstructural protein 2C co-localized with LC3 and mannose-6-phosphate receptor (MPR, endosome marker) proteins by immunofluorescence staining, indicating amphisome formation. Together with amphisome formation, EV71 induced an autophagic flux, which could be blocked by NH₄Cl (inhibitor of acidification) and vinblastine (inhibitor of fusion), as demonstrated by Western blotting. Suckling mice intracranially inoculated with EV71 showed EV71 VP1 protein expression (representing EV71 infection) in the cerebellum, medulla, and pons by immunohistochemical staining. Accompanied with these infected brain tissues, increased expression of LC3-II protein as well as formation of LC3 aggregates, autophagosomes and amphisomes were detected. Amphisome formation, which was confirmed by colocalization of EV71-VP1 protein or LC3 puncta and the endosome marker protein MPR. Thus, EV71-infected suckling mice (similar to EV71-infected SK-N-SH cells) also show an autophagic flux. The physiopathological parameters of EV71-MP4 infected mice, including body weight loss, disease symptoms, and mortality were increased compared to those of the uninfected mice. We further blocked EV71-induced autophagy with the inhibitor 3-methyladenine (3-MA), which attenuated the disease symptoms and decreased the viral load in the brain tissues of the infected mice.

Conclusions

In this study, we reveal that EV71 infection of suckling mice induces an amphisome formation accompanied with the autophagic flux in the brain tissues. Autophagy induced by EV71 promotes viral replication and EV71-related pathogenesis.     

(s)-DHPA在小白鼠乳鼠体内对流行性出血热病毒抑制作用的初步观察

本文报道了(s)—9—(2,3-dihydroxypropyl)adenine(简称(s)-DHPA)对流行性出血热(EHF)病毒J_(10)株感染小白鼠乳鼠的影响。实验表明,两个(s)-DHPA治疗组感染乳鼠的发病率(44.44％、55.17％)和感染率(44.44％、55.17％)均较对照组的发病率(83.33％)和感染率(86.96％)明显降低。实验结果提示,(s)-DHPA具有一定的抑制EHF病毒在小白鼠乳鼠体内复制的作用,为临床开发治疗EHF的抗病毒新药提供了实验室依据。     

流行性出血热病毒感染家猪的实验

本实验证明猪为流行性出血热病毒(EHFV)的敏感实验动物。从啮齿动物中分离的动物源株(R_(22))和从EHF患者血中分离的人源株(HB_(55))都可感染猪,并可在其体内许多组织中复制增殖。家猪在接种EHFV后第6—9天有一个短暂的发烧期,表现出病毒血症。于接种后的第7—11天(R_(22))和7～20天(HB_(55))可在组织中、特别是脾和肺中,用直接免疫荧光技术(DFA)很容易地捡出EHFV抗原。亦可在感染EHFV的猪血中检出EHFV抗体。从感染后的荧光阳性猪脾、肺可分离出感染性病毒。但R_(22)病毒株在感染猪后的第15天便完全消失,而HB_(55)株在感染后的第20天仍可查见,似乎动物源株(R_(22))和人源株(HB_(55))有所差异,然而都对家猪有感染性。从而,首次证实了家猪为EHFV的敏感实验动物,可作为EHFV的分离,增殖及疫苗研制等的新动物模型。这一发现,对EHF的研究将起积极作用,也提示猪在EHF流行病学上的意义不可忽视。     

轮状病毒致乳鼠肝脏IFN-γ/IL-10的变化研究

目的建立乳鼠感染的模型,检测轮状病毒（Rotavirus,RV）肠道内、外感染乳鼠肝脏IFN-γ和IL-10水平,比较肝脏IFN-γ和IL-10在轮状病毒肠道内外感染,以及不同时间点变化的差异性,进一步探讨IFN-γ和IL-10免疫自稳失衡与轮状病毒肠道外感染发病的关系,推测以恢复细胞因子平衡为目标的治疗策略可能是治疗轮状病毒肠炎的一种新方法。方法实验动物选用35日龄的清洁级BALB/C乳鼠,将54只乳鼠随机分为3组,每组18只,即实验组,包括肠道外组：通过腹腔注入0.10 mL（1×10-5）TCID50感染性滴度计量的SA-11株病毒;肠道内组：通过口腔灌入0.10 mL相同病毒;对照组无特殊处理。感染后,各组动物隔离饲养。观察乳鼠的活动、饮食、体型、毛色和大便变化情况等,收集大便经胶体金法检测其中RV抗原。在接种后的3、5和8 d处死乳鼠,留取肝脏,免疫组化方法检测IFN-γ和IL-10水平。结果对照组2种细胞因子表达量较少,肠道内组IFN-γ水平在接种RV后的第3天明显增多,第3天至第8天缓慢减少;IL-10水平较正常组增高但整个过程未见明显变化。肠道外组IFN-γ水平与肠道内组比较差异无统计学意义;IL-10水平在感染第3天也明显增多,第3天至第8天有所减少但仍存在且高于正常组。结论 BALB/C乳鼠肠道内外感染RV动物模型建立成功。乳鼠肠道外感染早期及后期肝脏内细胞因子呈现出不同改变。所以在肠道外组,肝脏细胞因子平衡机制失衡,进一步阐明这种失衡可能是RV肠道外播散的重要机制。     

汉滩病毒核蛋白与热休克蛋白GRP94、HSP27的相互作用

为研究汉滩病毒(Hantaan virus,HTNV)感染诱导乳鼠脑组织热休克蛋白GRP94、HSP27与病毒蛋白的相互关系,选出生2—3d的昆明乳鼠实验性感染汉滩病毒,取8d后发病乳鼠脑组织部分制石蜡切片,用免疫组化结合共聚焦显微镜检测组织中病毒抗原及GRP94、HSP27的表达,部分制匀浆液,用ELISA、免疫共沉淀方法分析病毒抗原和GRP94、HSP27的关系。结果示汉滩病毒感染诱导乳鼠脑组织神经细胞高表达GRP94且与细胞内病毒抗原有共定位关系,但未见HSP27诱导高表达;免疫共沉淀显示汉滩病毒核心抗原(HINV—NP)与GRP94、HSP27呈非共价复合物形式存在。该结果为进一步探讨HSPs在病毒感染复制中的作用以及抗病毒感染方面提供了有意义的实验资料。