C and V proteins of Sendai virus target signaling pathways leading to IRF-3 activation for the negative regulation of interferon-beta production

We here report a molecular basis for downregulation of interferon (IFN)-beta production by V and C proteins of Sendai virus (SeV). The infection of HeLa cells with SeV poorly induced IFN-beta even if the expression of C/C' was disrupted. In contrast, when the expression of C/C'/Y1/Y2 or V/W was disrupted, SeV infection strongly induced IFN-beta production and significantly activated the interferon regulatory factor (IRF)-3 pathway. The independent expression of C or V inhibited the double-stranded (ds) RNA- or Newcastle disease virus (NDV)-induced activation of IRF-3 and NF-kappa B, as well as the IFN-beta promoter. This inhibitory effect was also observed when Y1, Y2, or a C-terminal half fragment (aa 85-204) of C was independently expressed. Phosphorylation and homodimer formation of IRF-3 were suppressed not only in cells infected with SeV capable of expressing both C/C'/Y1/Y2 (or Y1/Y2) and V/W, but also in HeLa cells constitutively expressing Y1. These results suggest that C, Y1, Y2, and V block signaling pathways leading to IRF-3 activation to downregulate IFN-beta production.     

Sendai virus particles carrying target virus glycoproteins for antibody induction

Induction of antibodies targeting viral glycoproteins is a key for the development of a vaccine against enveloped virus infection. Glycoproteins on the virion exhibiting native multimer structure may be a good immunogen to present antibody epitopes, but it is often difficult to prepare immunogenic inactivated virions. Preparation of soluble glycoprotein multimers has been attempted, while virus-like particles carrying target glycoproteins can be a more immunogenic antigen. In the present study, a target glycoprotein-embedded Sendai virus (SeV) particle was developed for induction of anti-virus antibodies. We constructed a chimeric antigen, HIV-1 EnvF, consisting of HIV-1 Env ectodomain and SeV F transmembrane-cytoplasmic domain, which was shown to be efficiently incorporated into the SeV virion. EnvF was recognized by anti-HIV-1 broadly-neutralizing monoclonal antibodies (bnAbs) including 35O22 that targets an Env trimer-dependent epitope. Analysis revealed that HIV-1_AD8 EnvF can mediate viral entry into the cells, which is inhibited by anti-HIV-1 bnAbs and HIV-1 entry inhibitors, suggesting that the EnvF exhibits an HIV-1 Env native-like functional structure to present bnAb epitopes. Immunization of mice with replication-defective SeVs expressing HIV EnvF and non-infectious SeV particles (NVP) carrying HIV EnvF efficiently induced anti-HIV Env antibodies. HTLV-1 EnvF also showed the potential to efficiently induce anti-HTLV-1 Env antibodies. These results indicate that SeV particles carrying EnvF can be a promising vaccine platform for induction of antibodies targeting enveloped virus glycoproteins.     

Recombinant Sendai viruses with L1618V mutation in their L polymerase protein establish persistent infection, but not temperature sensitivity

The Sendai virus pi strain (SeVpi) isolated from cells persistently infected with SeV shows mainly two phenotypes: (1) temperature sensitivity and (2) an ability of establishing persistent infection (steady state). Three amino acid substitutions are found in the Lpi protein and are located at aa 1088, 1618, and 1664. Recombinant SeV(Lpi) (rSeV(Lpi)) having all these substitutions is temperature sensitive and is capable of establishing persistent infection (steady state). rSeVs carrying the fragment containing L1618V show both phenotypes. rSeV(L1618V), in which leucine at aa 1618 is replaced with valine, has the ability of establishing persistent infection, but is not a temperature-sensitive mutant, indicating that the ability of a virus to establish persistent infection can be separated from temperature sensitivity. The amino acid change at 1618(L-->V) coexisting with aa 1169 threonine is required for acquirement of a temperature-sensitive phenotype. Three amino acid substitutions are also found in the Ppi protein, but rSeV(Ppi) does not show these phenotypes.     

Evaluation of the chronotropic property of captopril in hypertensive patients

Captopril was administered (50 mg orally) to 88 untreated hypertensive patients (70 with essential hypertension, eight with renal arterial disease, 10 with renal parenchymal disease) and to 25 hypertensive patients treated with sympatholytic or beta-blocking agent (20 with essential hypertension, five with renal arterial disease). In the former group, captopril caused a decrease in heart rate (HR) in 18 patients and an increase in only two. As a whole, captopril caused significant decreases in blood pressure without increase in HR. Significant negative correlation was observed between change in HR and plasma renin activity obtained before captopril administration (n = 79, r = -0.425, p less than 0.0001). Hypotensive and chronotropic effects of captopril were almost identical in untreated and treated patients. Hypotensive effects caused by captopril and nifedipine (20 mg orally) were almost identical. Nifedipine caused reflex tachycardia, while captopril caused slight bradycardia. Absence of compensatory tachycardia appears to be related to reduction of endogenous angiotensin II by captopril.U     

仙台病毒 Tianjin 株缺陷干扰颗粒体内外诱导大鼠脑胶质瘤细胞凋亡的研究

目的探讨仙台病毒Tianjin株缺损干扰颗粒（ defective interfering particles ,DI颗粒）体内外诱导大鼠脑胶质瘤细胞C6凋亡的作用。方法将不同滴度仙台病毒Tianjin株DI颗粒分别与大鼠脑胶质瘤细胞C6作用不同时间,以培养基作为阴性对照、完整病毒作为阳性对照,通过DNA片段琼脂糖凝胶电泳、TUNEL染色、AnnexinⅤ-FITC/PI标记流式细胞仪分析等检测细胞凋亡情况。建立大鼠皮下胶质瘤模型,通过测量肿瘤大小观察DI颗粒抑瘤作用,病理切片HE染色观察肿瘤组织病理变化,TUNEL法检测肿瘤组织细胞凋亡情况。结果 C6细胞在体外经DI颗粒诱导后, DNA片段琼脂糖凝胶电泳呈阶梯状;流式细胞仪及TUNEL检测显示,DI颗粒组与完整病毒组细胞凋亡率明显增高,且呈时间-剂量依赖型。动物实验结果显示,DI颗粒和完整病毒均可明显抑制肿瘤生长;肿瘤组织病理切片HE染色显示DI颗粒组和完整病毒组瘤结节内瘤细胞较少;TUNEL原位细胞凋亡检测显示DI颗粒组和完整病毒组凋亡细胞明显增加,以上结果与阴性对照组比较差异均有统计学意义（P＜0．01）。结论仙台病毒Tianjin株DI颗粒在体内外均能引起大鼠脑胶质瘤C6细胞凋亡,且呈时间-剂量依赖型,提示DI颗粒有辅助治疗脑胶质瘤的可能性。     

Three unique Sendai virus antigenic peptides screened from nucleocapsid protein by overlapping peptide array

Sendai virus (SeV) is strictly monitored in laboratory rodents. Currently, complete virions have been used as antigens in SeV serological tests. However, the complexity of SeV virion antigen limits the accuracy of the diagnostic method. In the current study, complete SeV virion antigen was separated on SDS-PAGE and analyzed, with nucleocapsid protein (NP) showing predominant antigenicity. A peptide array containing overlapping 14-mer peptides covering the entire NP was developed. The array used SeV positive serum and resulted in four antigenic linear peptides being identified, which were located in the carboxyl-terminus of NP. The four peptides were coated on ELISA plates and tested with SeV positive and SeV negative sera, and the antigenicity of three peptides, NP413–428, NP473–490 and NP507–524, was confirmed. Mixture of the three peptides showed comparable sensitivity and better specificity in clinical rat sera ELISA tests compared with complete SeV virion antigen. In conclusion, the three peptides, NP413–428, NP473–490 and NP507–524, would be good candidates as linear antigens for SeV detection.     

Hepatic steatosis and the elevated plasma insulin level in patients with endogenous hypertriglyceridemia

Among 31 nonobese or obese patients with endogenous hypertriglyceridemia, hepatic steatosis was found by histologic examination of the biopsied specimen in 17 patients, and it was severe in six patients. They had no history of excessive alcohol intake. Chemical analysis revealed that the lipid accumulated in the liver was triglyceride. The hypertriglyceridemic patients, with or without histologic steatosis, showed significantly increased responses of both plasma insulin and blood glucose to oral glucose load compared with control subjects. The responses were more exaggerated in the hypertriglyceridemic patients with steatosis than in the hypertriglyceridemic patients without steatosis. Analysis of correlations between five variables (liver triglyceride, plasma insulin, blood glucose, body weight index, and serum triglyceride) was done on 15 subjects whose liver triglyceride values were quantified, and highly significant correlations were found between liver triglyceride and plasma insulin, blood glucose, or body weight index. A stepwise multiple regression analysis performed on the five variables with liver triglyceride as the dependent variable revealed that the plasma insulin level was the most closely related variable, and the blood glucose level the next. The prediction equation for liver triglyceride as a function of plasma insulin and blood glucose levels (r = 0.91, p < 0.001) accounted for 84% of the total variance of liver triglyceride. It was shown that the decay of intravenously injected insulin in plasma was not delayed in the hypertriglyceridemic patients with steatosis, while the insulin sensitivity examined after intravenous insulin injection significantly decreased in the hypertriglyceridemic patients with or without steatosis, thus suggesting that the hyperinsulinemia in the hypertriglyceridemic patients was due to an increased insulin secretion associated with the decrease in the insulin sensitivity. Therefore, the elevated plasma insulin and blood glucose levels—or the insulin insensitivity by itself—might be the essential abnormalities in patients with endogenous hypertriglyceridemia, which, in extreme cases, might lead to massive triglyceride accumulation in the liver.     

仙台病毒RT-LAMP可视化检测方法的建立

目的: 建立一种快捷、灵敏的检测方法,即反转录-环介导等温扩增方法(RT-LAMP)用于仙台病毒(SeV)的检测。方法: 根据GenBank 公布的SeV序列,在其保守区域设计了多套LAMP引物,利用LAMP Real Time Turbidimeter LA-320C仪监测反应进程并筛选最佳引物、反应条件,建立对SeV核酸进行特异性扩增的RT-LAMP 检测方法,并可通过加入目测荧光检测试剂肉眼判断结果。对所建立的方法进行了敏感性、特异性评估并对92份样品进行了检测。结果: 该方法在63℃恒温下作用60min,SeV RNA获得了高效率的特异性扩增,与其余常见小鼠病毒无交叉反应;其敏感性高,最低检出量为2.1TCID50SeV,比RT-PCR方法高102倍。在反应结束后加入荧光检测试剂肉眼判断结果,与RealTime Turbidimeter LA-320 仪监测结果一致。通过对92份样品的RT-LAMP,RT-PCR和间接ELISA方法的检测比对,三者符合率为100%。 结论: 本研究建立的SV RT- LAMP 检测方法具有快速、特异、灵敏,操作简单的特点,具有良好的应用前景。     

核酸疫苗pVAX1-F的构建及瞬时表达

目的:构建仙台病毒核酸疫苗pVAXl-F,并在COS 7细胞中表达.方法:利用PCR法以仙台病毒cDNA为模板扩增出F基因,与pMD18-T连接,测序正确后用HindⅢ/EcoR Ⅰ双酶切,将F基因引入经同样酶切的pVAX1载体,构建pVAX1-F表达载体,用PCR法和双酶切法鉴定,并将此重组质粒通过脂质体介导转染COS 7细胞,流式细胞术检测抗原蛋白表达、RT-PCR法检测外源基因的表达.结果:经PCR法和酶切鉴定,目的片段大小与预期相符,经测序目的基因序列与GenBank(EF679198)公布结果一致.重组质粒pVAX1-F转染COS 7细胞72 h后,能够表达抗原蛋白,流式细胞术检测达到58.3%,与对照组3.6%比较差异具有显著性(P<0.01),且F基因mRNA明显表达.结论:成功构建pVAX1-F,并能够在COS 7细胞中瞬时表达,为仙台病毒F基因核酸疫苗进行免疫学评价奠定基础.     

Mucociliary dysfunction in experimental otitis media with effusion

To investigate the morphologic changes of the eustachian tube mucociliary transport systems, experimental otitis media with effusion was induced by immune complex injection into the bullae of experimental animals. Horseradish peroxidase was chosen as an antigen because of its high antigenicity and traceability under light and electron microscopy. Seventy-three guinea pigs and 41 chinchillas were divided into three groups: active Arthus group, passive Arthus group, and control group. Animals were killed under general anesthesia from the first to 30th day after the injection. Within 5 days after injection, effusions were observed consistently in all animals, but in only 80 per cent on the 7th day and in only 50 per cent after the 10th day after injection. The most conspicuous findings were that the interciliary space of the mucociliary system was diffusely occupied by an electron-dense mucus, and the upper part of the ciliary shafts were tightly glued together. These features seem to indicate rheologic alterations of the mucus and a disorder of its coupling to the cilia. This study strongly suggests that the mucociliary coupling disorder caused by altered rheologic properties of the mucus causes clearance dysfunction of the eustachian tube, resulting in middle ear effusion. The various inflammatory products contained in the middle ear effusions elicit a persistent vicious cycle of inflammatory reactions in the tubotympanum.