2004-2006年吉林省流行性感冒病原学变化特点

目的探讨吉林省流行性感冒的病原学变化特点。方法根据2004—2006年流感监测结果对吉林省流感的流行趋势、病原学变化特点进行综合分析。用细胞培养法分离并鉴定流感病毒，用微量半加敏血凝抑制试验方法检测人群中抗流感病毒抗体水平。结果监测哨点医院2004—2006年临床诊断的流感样病例数基本持平，冬季可见1个波峰；全省发生暴发疫情0起；两个监测年从1350标本中分离病毒71株，其中甲1型39株（54．93％），甲3型7株（9．86％），乙型（yamagata株系）流感病毒24株（33．80％），乙型（victorian株系）流感病毒1株（1．41％），正常人群抗体水平测定以抗A3抗体最高，抗乙型（victorian株系）抗体最低。结论2004—2006年吉林省流感流行以低水平散发为主。提示在今后的监测工作中除了及时发现甲型变异株的出现，还应密切关注乙型（victorian株系）的流行动态。     

血凝素蛋白裂解位点对H5亚型禽流感病毒侵入细胞的影响

目的通过RT—PCR反应获得了H5N1亚型禽流感病毒完整的血凝素基因（HA）并克隆到真核表达载体pcDNA3上，通过转染293T细胞进行了瞬时表达验证。方法采用PCR定点突变技术，将其HA基因裂解位点的氨基酸组成由RKKR↓GLF突变为RSSR↓GLF，使其具有低致病性AIV的分子特征，并构建了表达突变后HA基因的真核表达载体pcDNA—Hm。将pcDNA—H5和pcDNA—Hm分别与MuLV假病毒构建体系的两种质粒pHTT60和pHIT111共转染转化了SV40大T抗原的人胚肾细胞293T后，收集转染细胞上清，通过Western—blot和细胞感染性实验来研究假病毒的特性。用缺乏囊膜蛋白和已经证实可以形成MuLV假病毒的水泡性口炎病毒糖蛋白G作为对照。结果转染后形成假病毒进行裂解后进行Westem—blot证明两种HA蛋白都能够整合到各自的假病毒颗粒表面，野生型的HA可以检测到三条带，分别与HA0、HA1和HA2大小相符，而突变后的HAm则仅能检测到一条带，与HA前体大小相符，说明其失去了裂解活性。通过感染293T、COS-7和NIH3T3三种不同的靶细胞后发现野生型的HA所形成的假病毒MuLV—H5具有感染性和泛嗜性，而突变后的HA所形成的假病毒则失去了感染性。结论可以得出HA蛋白裂解位点的氨基酸组成不仅对H5亚型禽流感病毒的致病性有影响，对禽流感病毒侵入细胞也具有至关重要的作用。     

Construction of eukaryotic expressing plasmids encodingHA andHA 1 of influenza A virus and their transient expression in HEK293 cells

Summary In order to explore the feasibility and protective efficiency of influenza DNA vaccine, we constructed eukaryotic expressing plasmids encodingHA andHA ₁ of influenza A virus (A/PR/8/34) and studied their expression in HEK293 cells.HA andHA ₁ genes were amplified by RT-PCR and cloned into pcDNA3. 1(+) to generate pcDNA3. 1(+)/HA and pcDNA3.1(+)/HA₁, respectively. After verification of the cloning fidelity by restriction endonuclease digestion, PCR, and sequencing, pcDNA3. 1(+)/HA and pcDNA3.1(+)/HA₁ were transfected into HEK293 cells using PolyFect Transfection Reagent. Immunofluorescence assay was used to detect the transient expressing cells. Fluorescence microscopy revealed strong expression of target gene in HEK293 cells transiently transfected with either pcDNA3.1(+)/HA or pcDNA3.1(+)/HA₁. Therefore, the results confirm the successful construction of eukaryotic expressing plasmids capable of driving the eukaryotic expression of influenza virus antigen HA and HA₁, which is likely to provide a basis for both further investigation of the mechanism of influenza viral infection and the development of influenza DNA vaccine. Zhang Weidong, female, born in 1970, M. D., Ph. D. This project was supported by a grant from the National Natural Sciences Foundation of China (No. 39970830).     

知母宁体外抗甲型流感病毒作用研究

目的:考察知母宁体外抗甲型流感病毒作用.方法:以利巴韦林作阳性对照药物,用中性红染色法测定知母宁不同加药方式对甲型人流感病毒H1N1的体外抑制作用及其时效关系.结果:知母宁对甲型人流感病毒具明显的综合抑制作用及抑制病毒吸附后的复制增殖作用,这两种作用的半数有效浓度(EC50)分别为0.70及0.76 mg·ml-1.知母宁对病毒吸附的预防作用弱,无直接杀伤病毒的作用.随药物作用时间延长,知母宁在低浓度抗病毒有效率呈减小趋势,在高浓度时(≥1.4 mg·ml-1)其抗病毒能力基本不变.同时知母宁可明显降低病毒的感染性.结论:知母宁具有明显的体外抗甲型人流感病毒作用.     

生产用流感疫苗候选病毒株复制能力的提高

流感疫苗生产主要采用鸡胚病毒培养的方式,而提高流感病毒在鸡胚中的复制能力将能增加疫苗的产量和可靠性.影响病毒在鸡胚中繁殖的重要因素包括:流感病毒血凝素部分位点的氮基酸变异、血凝素与神经氨酸酶之间的作用平衡、病毒其他蛋白的作用及8个基因节段的重配比例.疫苗株制备方法瓶颈的突破和乙型流感病毒重配株的研究也将帮助疫苗生产商选择合适的候选疫苗株.     

Influenzaimpfung – für Risikogruppen besonders wichtig

Every year influenza infections leads to hospitalizations, deaths and days missed from work and school. However, influenza is a vaccine-preventable disease. Measures to improve vaccination rates among risk groups and healthcare personnel ought to be an important public health goal.     

In the Shadow of Hemagglutinin: A Growing Interest in Influenza Viral Neuraminidase and Its Role as a Vaccine Antigen

Despite the availability of vaccine prophylaxis and antiviral therapeutics, the influenza virus continues to have a significant, annual impact on the morbidity and mortality of human beings, highlighting the continued need for research in the field. Current vaccine strategies predominantly focus on raising a humoral response against hemagglutinin (HA)—the more abundant, immunodominant glycoprotein on the surface of the influenza virus. In fact, anti-HA antibodies are often neutralizing, and are used routinely to assess vaccine immunogenicity. Neuraminidase (NA), the other major glycoprotein on the surface of the influenza virus, has historically served as the target for antiviral drug therapy and is much less studied in the context of humoral immunity. Yet, the quest to discern the exact importance of NA-based protection is decades old. Also, while antibodies against the NA glycoprotein fail to prevent infection of the influenza virus, anti-NA immunity has been shown to lessen the severity of disease, decrease viral lung titers in animal models, and reduce viral shedding. Growing evidence is intimating the possible gains of including the NA antigen in vaccine design, such as expanded strain coverage and increased overall immunogenicity of the vaccine. After giving a tour of general influenza virology, this review aims to discuss the influenza A virus neuraminidase while focusing on both the historical and present literature on the use of NA as a possible vaccine antigen.     

Evaluation of Border Entry Screening for Infectious Diseases in Humans

In response to the severe acute respiratory syndrome (SARS) pandemic of 2003 and the influenza pandemic of 2009, many countries instituted border measures as a means of stopping or slowing the spread of disease. The measures, usually consisting of a combination of border entry/exit screening, quarantine, isolation, and communications, were resource intensive, and modeling and observational studies indicate that border screening is not effective at detecting infectious persons. Moreover, border screening has high opportunity costs, financially and in terms of the use of scarce public health staff resources during a time of high need. We discuss the border-screening experiences with SARS and influenza and propose an approach to decision-making for future pandemics. We conclude that outbreak-associated communications for travelers at border entry points, together with effective communication with clinicians and more effective disease control measures in the community, may be a more effective approach to the international control of communicable diseases.     

Initial HRCT findings of novel influenza A (H1N1) infection

Please cite this paper as: Yuan et al. (2012) Initial HRCT findings of novel influenza A (H1N1) infection. Influenza and Other Respiratory Viruses 6(601), e114–e119. Objectives The aim of our study was to describe the presentation and illustrate the imaging features of chest high‐resolution computed tomography (HRCT) of patients with novel influenza A (H1N1) virus infection. Methods Data were collected from 163 hospitalized patients between November 2009 and March 2011, who fulfilled the clinical criteria for H1N1 influenza infection and underwent HRCT examinations within 24 hours of admission. Results Abnormal findings were observed in 40·5% of the patients. The patients with positive imaging findings were significantly older than patients with normal HRCT findings (P = 0·02). The most common finding was ground‐glass opacity (GGO) (n = 35). Interlobular septal thickening (n = 31) and centrilobular nodules (n = 30) were the second most frequent findings. Other common findings were consolidation, reticulation, and linear shadow. The most common imaging finding for lung involvement was GGO with a patchy pattern. Pulmonary involvement of the disease may be extensive and variable, but the total volume of affected lung was mostly <1 lobe. Conclusion The baseline HRCT may be valuable and suggestive even for non‐severe H1N1 infections. When a severe case or a evolution is suspected, chest CT could be essential both for determining the precise extent of parenchymal damage and for monitoring its evolution.