The present study was supported by the NIH grants HL120947 (P.C.), HL103868 (P.C.), and the American Heart Association Grant-in-Aid (P.C.)

注：总论：执行涉及操纵在无菌条件下的蛋的所有程序，和无菌技术应相应地使用。预清洁所有的设备用70％乙醇后再使用。在一般情况下，流感病毒接种和收获应在BSL-2实验室中进行。但是，如果该协议被用于传播更多的致病性流感病毒（ 例如 ，流感大流行和大流行前的菌株，即危及家禽和牲畜，人感染高致病性禽流感毒株，1918年的H1N1病毒株），更高的生物安全水平，在某些情况下，生物安全防范措施和授权是必需的。当地生物安全委员会应批准涉及流感病毒的所有研究工作。 1.准备鸡蛋的接种<ol><li>从合适的供应商处获得的血清的无病原体（SPF）的新鲜受精禽卵。通常情况下，鸡卵被使用。鸡蛋应该是我们ED抵达后立即。 </li><li>抵达后的地方鸡蛋一个鸡蛋加湿孵化器与自动鸡蛋特纳经常转动鸡蛋。如果自动鸡蛋特纳不可用，手动旋转鸡蛋一天（一定要戴上手套并保留一切无菌地）至少2-3次。 </li><li>孵化卵在37℃和55-60％湿度为10-11天。 </li></ol> 2.鸡蛋烛<ol><li>用一个鸡蛋烛台检查对着明亮光线的鸡蛋在一个黑暗的房间通过后约7或8天的潜伏期烛检查鸡蛋不育。 <ol><li>擦蛋烛台，用70％的乙醇。经常更换手套和用70％乙醇消毒，以减少污染的病原体的风险。 </li><li>从孵化器中取出卵子，并将它们放在空的鸡蛋盒。 </li><li>关灯的房间。 </li><li>保持每个鸡蛋一体的大型月底在对烛台时间。 </li><li>观察蛋determinË如果是肥沃还是贫瘠。 注：细血管导致豆形胚应清晰可见。未受精的卵子会出现一个小血点有明显的蛋黄。 </li></ol></li><li>丢弃卵是受精，并返回可行蛋的孵化器。不要让鸡蛋孵化器外超过30分钟。如果一个鸡蛋的状态不能得到证实，将其标记，后来观察它。 </li></ol> 3.编写病毒的接种<ol><li>稀释的流感病毒原液至约10 3 -在无菌PBS中含有10mM HEPES（pH 7.4）中10 4 PFU / ml的。关键的一步：在使用前稀释病毒的股票，并保持病毒稀释冰上所有的时间。 </li></ol>通过尿囊路线4.流感病毒接种<ol><li>在病毒接种（10天或11）的一天，再次蜡烛鸡蛋和消除任何死胚。区分活胚胎通过找蛋内运动。 </li><li>从培养箱中取出三个鸡蛋，并安排在鸡蛋中与空气囊一个单独的支架。 </li><li>纪念鸡蛋用永久性记号笔的领空。 </li><li>洗蛋壳，用70％的乙醇的空气空间的上方。 </li><li>把鸡蛋与空气的空间在一个鸡蛋纸箱和成生物安全罩（BSL-2）。 </li><li>使用无菌18G针头打一个小孔，在外壳上每个鸡蛋的空气囊。要注意不要插入针过深，以免刺伤胚胎或蛋黄。 </li><li>拟定稀释流感病毒进入无菌1ml注射器，并附加一个22G针头。 </li><li>认真推进针注射器以45°角插入尿囊腔。 </li><li>注入0.2毫升稀释的流感病毒。 </li><li>重复注射与其他两个鸡蛋，然后丢弃的注射器和针头。 </li><li>密封带从胶枪（或熔融石蜡）一滴粘结剂的孔。 BË小心，胶水不漏蛋内。 </li><li>将鸡蛋放回蛋孵化器与空气空间指向向上。 </li><li>重复步骤4.2 - 4.12，直到所有的鸡蛋都已经接种。 </li></ol> 5.孵化时间<ol><li>孵育感染鸡蛋无需转动，在37℃和〜60％的湿度。 </li><li>选择最佳孵育时间取决于流感病毒的类型。孵化甲型流感48小时;孵育流感B和C为72小时。 </li></ol> 6.流感病毒收获<ol><li>经过潜伏期，寒意鸡蛋在4℃最少4小时（或O / N）杀死胚胎和收缩血管，减少污染的血液被感染的尿囊液的风险。这样做是为了防止红血细胞从吸收的病毒，从而降低了产率。可替代地，寒意鸡蛋30分钟在-20℃;然而，这会增加血液污染的风险。 </li><li>之后的鸡蛋被充分冷却，卵转移到生物安全罩。将蛋与气囊朝上牢固夹持。清洁蛋表面用70％的乙醇。 </li><li>用无菌剪刀打开上方的空气囊的蛋壳。周围的空气囊去掉外壳，注意不要破坏绒毛尿囊膜。 </li><li>打开绒毛尿囊膜，用无菌钝钳。轻轻移动胚胎和卵黄囊用小刮刀或汤匙放在一边。小心不要破裂的蛋黄。 </li><li>用1毫升的Eppendorf移液器，仔细收集尿囊液。如果需要的话，倾斜鸡蛋有点一边收集尽可能多的流体越好。 </li><li>组合来自所有鸡蛋尿囊液到50ml的塑料离心管中。保持病毒收获期间冰在任何时候都管。一个鸡蛋产量5 - 10毫升一个淡黄色的液体。 </li><li>旋转含有病毒的尿囊液在1000×g离心，在4 10分钟6℃到沉淀杂物。转移透明流体到一个新的50ml管中保持在冰上。配置鸡蛋放入一个BSL-2的废弃物容器。 </li></ol> 7.储存<ol><li>立即等分澄清尿囊液（ 例如，50，100或500微升等分试样）和单元冷冻在液氮中。传输冻病毒储存至-80℃冰箱长期保存。 </li></ol>

<ol>
	<li>Centers for Disease Control and Prevention (CDC). <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estimates+of+deaths+associated+with+seasonal+influenza+---+United+States,+1976-2007.">Estimates of deaths associated with seasonal influenza --- United States, 1976-2007.</a> MMWR. Morbidity and mortality weekly report. 59 (33), 1057-1062 (2010).</li><li>Neumann, G., Noda, T., Kawaoka, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Emergence+and+pandemic+potential+of+swine-origin+H1N1+influenza+virus.">Emergence and pandemic potential of swine-origin H1N1 influenza virus.</a> Nature. 459 (7249), 931-939 (2009).</li><li>Tumpey, T. M., Garcia-Sastre, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pathogenicity+of+Influenza+Viruses+with+Genes+from+the+1918+Pandemic+Virus:+Functional+Roles+of+Alveolar+Macrophages+and+Neutrophils+in+Limiting+Virus+Replication+and+Mortality+in+Mice.">Pathogenicity of Influenza Viruses with Genes from the 1918 Pandemic Virus: Functional Roles of Alveolar Macrophages and Neutrophils in Limiting Virus Replication and Mortality in Mice.</a> J Virol. 79 (23), 14933-14944 (2005).</li><li>Doherty, P. C., Turner, S. J., Webby, R. G., Thomas, P. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influenza+and+the+challenge+for+immunology.">Influenza and the challenge for immunology.</a> Nat Immu. 7 (5), 449-455 (2006).</li><li>Webster, R. G., Govorkova, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Continuing+challenges+in+influenza.">Continuing challenges in influenza.</a> Ann N Y Acad Sci. 1323 (1), 115-139 (2014).</li><li>Szretter, K. J., Balish, A. L., Katz, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Unit+15G.1+Influenza:+propagation,+quantification,+and+storage.+.">Unit 15G.1 Influenza: propagation, quantification, and storage. .</a> Current protocols in microbiology. , (2006).</li><li>Short, K. R., Kroeze, E. J. B. V., Fouchier, R. A. M., Kuiken, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pathogenesis+of+influenza-induced+acute+respiratory+distress+syndrome.">Pathogenesis of influenza-induced acute respiratory distress syndrome.</a> Lancet Infect Dis. 14 (4), 57-69 (2014).</li><li>Ito, T., Suzuki, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differences+in+sialic+acid-galactose+linkages+in+the+chicken+egg+amnion+and+allantois+influence+human+influenza+virus+receptor+specificity+and+variant+selection.">Differences in sialic acid-galactose linkages in the chicken egg amnion and allantois influence human influenza virus receptor specificity and variant selection.</a> J Virol. 71 (4), 3357-3362 (1997).</li><li>Robertson, J. S., Nicolson, C., Major, D., Robertson, E. W., Wood, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+amniotic+passage+in+the+egg-adaptation+of+human+influenza+virus+is+revealed+by+haemagglutinin+sequence+analyses.">The role of amniotic passage in the egg-adaptation of human influenza virus is revealed by haemagglutinin sequence analyses.</a> J Gen Virol. 74 (Pt 10), 2047-2051 (1993).</li><li>Gaush, C. R., Smith, T. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Replication+and+plaque+assay+of+influenza+virus+in+an+established+line+of+canine+kidney+cells).">Replication and plaque assay of influenza virus in an established line of canine kidney cells).</a> Appl Microbiol. 16 (4), 588-594 (1968).</li></ol>

The authors have nothing to disclose.

流感导致疾病的一个大的全球负担，工作持续到了解肺损伤7的发病机制。以促进研究在这种致命的疾病，各种方法已经被开发来传播的流感病毒6。这里，我们描述了一种技术，以产生流感病毒在鸡卵。这种方法的优点是，它是高度可重复的，并导致大量的高滴度流感病毒的股票，这往往是必需的体外研究。 大多数实验室将能够快速，轻松地开发该协?...

甲型流感仍然是一个重大威胁人类健康。这是一个潜在的破坏性呼吸系统疾病有大型的全球性负担造成了全球每年1 500,000人死亡。流感病毒是在家庭正粘病毒和携带8负义单链RNA在它们的基因组1,2。病毒基因组的高可变性（ 即抗原“漂移”）防止长期免疫力。此外，流感是抗病毒的药物3日益抗性。 2009年甲型H1N1流感大流行强调所有流感病（流感病毒，抗病毒性，推迟疫苗的生产）相关的具有挑战性的问题。该疫苗配方是每年由世界卫生组织为最有可能致病的流感病毒株（分别为H1N1，H3N2和乙型流感）4确定。因为这种方法是基于预测流感病毒株S，致病菌株偶尔错误地标识和疫苗的有效性急剧下降。此外，新型流感病毒株的出现可以绕开造成流行病2这些预防计划。 一个通用流感疫苗的创作一直难以捉摸5。因此，研究必须继续为了解肺损伤的发病机制。到设施的实验室研究，几种方法已经被开发用于病毒分离和传播6。人流感病毒可以在多种哺乳动物细胞基质进行放大。然而，在大批量生成高滴度病毒最好在胚卵实现。以下协议描述的技术为A型流感病毒的传播和存储，从现有的病毒股票。

<table border="0" cellpadding="0" cellspacing="0" width="873">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Name of Reagent/ Equipment</td>
			<td style="width:225px;">Company</td>
			<td style="width:128px;">Catalog Number</td>
			<td style="width:167px;">Comments/Description</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Phosphate buffered saline (PBS)</td>
			<td style="width:225px;">Cellgro&#160;</td>
			<td style="width:128px;">21-040-CV</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">serum pathogen-free (SPF) fertilized chicken eggs&#160;</td>
			<td>VALO BioMedia</td>
			<td style="width:128px;">n/a</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">humidified egg incubator&#160;</td>
			<td>FARM iNNOVATORS</td>
			<td>Model 2100</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">automatic egg turner</td>
			<td>FARM iNNOVATORS</td>
			<td>Model 3200</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">egg candler</td>
			<td>FARM iNNOVATORS</td>
			<td>Model 3300&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">1 ml syringe</td>
			<td style="width:225px;">BD Bioscience</td>
			<td style="width:128px;">309659</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">18G needle</td>
			<td style="width:225px;">BD Bioscience</td>
			<td style="width:128px;">305196</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">20G / 22G needle</td>
			<td style="width:225px;">BD Bioscience</td>
			<td style="width:128px;">305176 / 305156</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">HEPES</td>
			<td style="width:225px;">Sigma-Aldrich</td>
			<td style="width:128px;">H3375</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Ethanol, &#62;99.5%</td>
			<td style="width:225px;">Sigma-Aldrich</td>
			<td style="width:128px;">459844</td>
			<td>diluted to 70% using water</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:353px;">glue gun &#34;Ad tech Hi Temp Project Pro&#34;</td>
			<td style="width:225px;">Ad tech, Adhesive Technologies, Inc.</td>
			<td>Model 1105</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:353px;">glue &#34;Ad tech MINI SIZE, Multi Temp&#34;</td>
			<td style="width:225px;">Ad tech, Adhesive Technologies, Inc.</td>
			<td>220-34ZIP30</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">MDCK cells</td>
			<td style="width:225px;">ATCC</td>
			<td>CRL-2935</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Washed Pooled Turkey Red Blood Cells, 10%</td>
			<td style="width:225px;">Lampire Biological Laboratories</td>
			<td>724908</td>
			<td></td>
		</tr>
	</tbody>
</table>

influenza virus propagation in embryonated chicken eggs

流感与约36000人死亡，每年有超过20万的住院在美国的关联。新的流感病毒株引起的突变，并重新分类连续出现复杂的病毒控制，并有必要的新颖的药物和疫苗的永久发展。流感的实验室为基础的研究中，需要对病毒的传播有可靠和具有成本效益的方法。在这里，一个全面的协议是为A型流感病毒的传播在肥沃的鸡蛋，它始终产生高滴度的病毒股票。简言之，血清的无病原体（SPF）的受精鸡蛋孵育在37℃和55-60％湿度下10 - 11天。在此期间，胚胎发育，可以很容易地用一个鸡蛋烛台监测。病毒接种是通过注射病毒原液的成使用的针的尿囊腔。后在37℃下孵育2天，将蛋冷冻至少4小时，在4℃。上方的空气囊和尿囊膜蛋壳然后小心地打开，并含有病毒的尿囊液收获。流体从碎屑清除通过离心，等分并转移至-80℃长期储存。大量（5-10毫升的病毒含有每蛋流体）和高病毒效价通常与该协议实现作出了鸡蛋的病毒制备我们的有利方法的使用，特别是用于在体外研究需要大量病毒在其中需要同样的病毒股票的高剂量。

多种方法已经发展到滴定流感病毒。当选择适当的方法之一的考虑是，某些确定总颗粒无论活力（ 例如 ，血凝素测定法），而其他人都基于感染性的，这将评估存活的病毒颗粒（ 例如 ，空斑测定）6。此处，尿囊液的病毒滴度从接种小鼠-适应的流感病毒（A / PR / 8/34）鸡卵收集空斑测定（ 图1）和血凝试验（ 图2）进行测定。 流...

Watch this Scientific Journal Video about Influenza Virus Propagation in Embryonated Chicken Eggs at JoVE.com

Influenza Virus Propagation in Embryonated Chicken Eggs

Fertile chicken eggs are widely used to produce large amounts of human influenza A virus as they provide a convenient and cost-effective system to prove high yields of virus.

在鸡胚的流感病毒传播

Influenza infection is associated with about 36,000 deaths and more than 200,000 hospitalizations every year in the United States. The continuous ...

influenza-virus-propagation-in-embryonated-chicken-eggs

Research

JoVE Journal

Immunology and Infection

42.6K 次观看.  Cedars-Sinai Medical Center. Fertile chicken eggs are widely used to produce large amounts of human influenza A virus as they provide a convenient and cost-effective system to prove high yields of virus.

视频: Influenza Virus Propagation in Embryonated Chicken Eggs

Generation of Recombinant Influenza Virus from Plasmid DNA

Efforts by a number of influenza research groups have been pivotal in the development and improvement of influenza A virus reverse genetics. Originally established in 1999 1,2 plasmid-based reverse genetic techniques to generate recombinant viruses have revolutionized the influenza research field because specific questions have been answered by genetically engineered, infectious, recombinant influenza viruses. Such studies include virus replication, function of viral proteins, the contribution of specific mutations in viral proteins in viral replication and/or pathogenesis and, also, viral vectors using recombinant influenza viruses expressing foreign proteins 3.

Rescue of influenza A viruses from plasmid DNA is a basic and essential experimental technique that allows influenza researchers to generate recombinant viruses to study multiple aspects in the biology of influenza virus, and to be used as potential vectors or vaccines.

质粒DNA重组流感病毒的一代

Efforts by a number of influenza research groups have been pivotal in the development and improvement of influenza A virus reverse genetics. Originally ...

科研

免疫与感染

High-throughput Detection Method for Influenza Virus

Influenza virus is a respiratory pathogen that causes a high degree of morbidity and mortality every year in multiple parts of the world. Therefore, precise diagnosis of the infecting strain and rapid high-throughput screening of vast numbers of clinical samples is paramount to control the spread of pandemic infections. Current clinical diagnoses of influenza infections are based on serologic testing, polymerase chain reaction, direct specimen immunofluorescence and cell culture 1,2.
Here, we report the development of a novel diagnostic technique used to detect live influenza viruses. We used the mouse-adapted human A/PR/8/34 (PR8, H1N1) virus 3 to test the efficacy of this technique using MDCK cells 4. MDCK cells (104 or 5 x 103 per well) were cultured in 96- or 384-well plates, infected with PR8 and viral proteins were detected using anti-M2 followed by an IR dye-conjugated secondary antibody. M2 5 and hemagglutinin 1 are two major marker proteins used in many different diagnostic assays. Employing IR-dye-conjugated secondary antibodies minimized the autofluorescence associated with other fluorescent dyes. The use of anti-M2 antibody allowed us to use the antigen-specific fluorescence intensity as a direct metric of viral quantity. To enumerate the fluorescence intensity, we used the LI-COR Odyssey-based IR scanner. This system uses two channel laser-based IR detections to identify fluorophores and differentiate them from background noise. The first channel excites at 680 nm and emits at 700 nm to help quantify the background. The second channel detects fluorophores that excite at 780 nm and emit at 800 nm. Scanning of PR8-infected MDCK cells in the IR scanner indicated a viral titer-dependent bright fluorescence. A positive correlation of fluorescence intensity to virus titer starting from 102-105 PFU could be consistently observed. Minimal but detectable positivity consistently seen with 102-103 PFU PR8 viral titers demonstrated the high sensitivity of the near-IR dyes. The signal-to-noise ratio was determined by comparing the mock-infected or isotype antibody-treated MDCK cells.
Using the fluorescence intensities from 96- or 384-well plate formats, we constructed standard titration curves. In these calculations, the first variable is the viral titer while the second variable is the fluorescence intensity. Therefore, we used the exponential distribution to generate a curve-fit to determine the polynomial relationship between the viral titers and fluorescence intensities. Collectively, we conclude that IR dye-based protein detection system can help diagnose infecting viral strains and precisely enumerate the titer of the infecting pathogens.

This method describes the use of Infrared dye based imaging system for detection of H1N1 in bronchioalveolar lavage (BAL) fluid of infected mice at a high sensitivity. This methodology can be performed in a 96- or 384-well plate, requires &lt;10 &mu;l volume of test material and has the potential for concurrent screening of multiple pathogens.

流感病毒的高通量检测方法

Influenza virus is a respiratory pathogen that causes a high degree of morbidity and mortality every year in multiple parts of the world. Therefore, ...

Affinity Purification of Influenza Virus Ribonucleoprotein Complexes from the Chromatin of Infected Cells

Like all negative-strand RNA viruses, the genome of influenza viruses is packaged in the form of viral ribonucleoprotein complexes (vRNP), in which the single-stranded genome is encapsidated by the nucleoprotein (NP), and associated with the trimeric polymerase complex consisting of the PA, PB1, and PB2 subunits. However, in contrast to most RNA viruses, influenza viruses perform viral RNA synthesis in the nuclei of infected cells. Interestingly, viral mRNA synthesis uses cellular pre-mRNAs as primers, and it has been proposed that this process takes place on chromatin1. Interactions between the viral polymerase and the host RNA polymerase II, as well as between NP and host nucleosomes have also been characterized1,2.
Recently, the generation of recombinant influenza viruses encoding a One-Strep-Tag genetically fused to the C-terminus of the PB2 subunit of the viral polymerase (rWSN-PB2-Strep3) has been described. These recombinant viruses allow the purification of PB2-containing complexes, including vRNPs, from infected cells. To obtain purified vRNPs, cell cultures are infected, and vRNPs are affinity purified from lysates derived from these cells. However, the lysis procedures used to date have been based on one-step detergent lysis, which, despite the presence of a general nuclease, often extract chromatin-bound material only inefficiently. 
Our preliminary work suggested that a large portion of nuclear vRNPs were not extracted during traditional cell lysis, and therefore could not be affinity purified. To increase this extraction efficiency, and to separate chromatin-bound from non-chromatin-bound nuclear vRNPs, we adapted a step-wise subcellular extraction protocol to influenza virus-infected cells. Briefly, this procedure first separates the nuclei from the cell and then extracts soluble nuclear proteins (here termed the "nucleoplasmic" fraction). The remaining insoluble nuclear material is then digested with Benzonase, an unspecific DNA/RNA nuclease, followed by two salt extraction steps: first using 150 mM NaCl (termed "ch150"), then 500 mM NaCl ("ch500") (Fig. 1). These salt extraction steps were chosen based on our observation that 500 mM NaCl was sufficient to solubilize over 85% of nuclear vRNPs yet still allow binding of tagged vRNPs to the affinity matrix.
After subcellular fractionation of infected cells, it is possible to affinity purify PB2-tagged vRNPs from each individual fraction and analyze their protein and RNA components using Western Blot and primer extension, respectively. Recently, we utilized this method to discover that vRNP export complexes form during late points after infection on the chromatin fraction extracted with 500 mM NaCl (ch500)3.

Influenza viruses replicate their RNA genome in association with host-cell chromatin. Here, we present a method to purify intact viral ribonucleoprotein complexes from the chromatin of infected cells. Purified viral complexes can be analyzed by both Western blot and primer extension of protein and RNA content, respectively.

流感病毒从感染细胞的染色质的核糖核蛋白复合物的亲和纯化

Like all negative-strand RNA viruses, the genome of influenza viruses is packaged in the form of viral ribonucleoprotein complexes (vRNP), in which the ...

Propagation of Homalodisca coagulata virus-01 via Homalodisca vitripennis Cell Culture

The glassy-winged sharpshooter (Homalodisca vitripennis) is a highly vagile and polyphagous insect found throughout the southwestern United States. These insects are the predominant vectors of Xylella fastidiosa (X. fastidiosa), a xylem-limited bacterium that is the causal agent of Pierce&#39;s disease (PD) of grapevine. Pierce&#8217;s disease is economically damaging; thus, H. vitripennis have become a target for pathogen management strategies. A dicistrovirus identified as Homalodisca coagulata virus-01 (HoCV-01) has been associated with an increased mortality in H. vitripennis populations. Because a host cell is required for HoCV-01 replication, cell culture provides a uniform environment for targeted replication that is logistically and economically valuable for biopesticide production. In this study, a system for large-scale propagation of H. vitripennis cells via tissue culture was developed, providing a viral replication mechanism. HoCV-01 was extracted from whole body insects and used to inoculate cultured H. vitripennis cells at varying levels. The culture medium was removed every 24 hr for 168 hr, RNA extracted and analyzed with qRT-PCR. Cells were stained with trypan blue and counted to quantify cell survivability using light microscopy. Whole virus particles were extracted up to 96 hr after infection, which was the time point determined to be before total cell culture collapse occurred. Cells were also subjected to fluorescent staining and viewed using confocal microscopy to investigate viral activity on F-actin attachment and nuclei integrity. The conclusion of this study is that H. vitripennis cells are capable of being cultured and used for mass production of HoCV-01 at a suitable level to allow production of a biopesticide.

Propagation of Homalodisca coagulata virus-01 via Homalodisca vitripennis Cell Culture

Here we present a protocol to propagate Homalodisca vitripennis cells and HoCV-1 in vitro. Medium was removed from HoCV-1 positive cultures and RNA extracted every 24 hr for 168 hr. Cell survivability was quantified by trypan blue staining. Whole virus particles were extracted post-infection. Extracted RNA was quantified by qRT-PCR.

传播<em&gt; Homalodisca coagulata病毒01</em&gt;通过<em&gt; Homalodisca vitripennis</em&gt;细胞培养

The glassy-winged sharpshooter (Homalodisca vitripennis) is a highly vagile and polyphagous insect found throughout the southwestern United States. These ...

Co-immunoprecipitation of the Mouse Mx1 Protein with the Influenza A Virus Nucleoprotein

Studying the interaction between proteins is key in understanding their function(s). A very powerful method that is frequently used to study interactions of proteins with other macromolecules in a complex sample is called co-immunoprecipitation. The described co-immunoprecipitation protocol allows to demonstrate and further investigate the interaction between the antiviral myxovirus resistance protein 1 (Mx1) and one of its viral targets, the influenza A virus nucleoprotein (NP). The protocol starts with transfected mammalian cells, but it is also possible to use influenza A virus infected cells as starting material. After cell lysis, the viral NP protein is pulled-down with a specific antibody and the resulting immune-complexes are precipitated with protein G beads. The successful pull-down of NP and the co-immunoprecipitation of the antiviral Mx1 protein are subsequently revealed by western blotting. A prerequisite for successful co-immunoprecipitation of Mx1 with NP is the presence of N-ethylmaleimide (NEM) in the cell lysis buffer. NEM alkylates free thiol groups. Presumably this reaction stabilizes the weak and/or transient NP&#8211;Mx1 interaction by preserving a specific conformation of Mx1, its viral target or an unknown third component. An important limitation of co-immunoprecipitation experiments is the inadvertent pull-down of contaminating proteins, caused by nonspecific binding of proteins to the protein G beads or antibodies. Therefore, it is very important to include control settings to exclude false positive results. The described co-immunoprecipitation protocol can be used to study the interaction of Mx proteins from different vertebrate species with viral proteins, any pair of proteins, or of a protein with other macromolecules. The beneficial role of NEM to stabilize weak and/or transient interactions needs to be tested for each interaction pair individually.

This co-immunoprecipitation protocol allows to study the interaction between the influenza A virus nucleoprotein and the antiviral Mx1 protein in human cells. The protocol emphasizes the importance of N-ethylmaleimide for successful co-immunoprecipitation of Mx1 and influenza A virus nucleoprotein.

免疫共沉淀鼠标MX1蛋白与流感病毒核蛋白

Studying the interaction between proteins is key in understanding their function(s). A very powerful method that is frequently used to study interactions ...

Nasal Wipes for Influenza A Virus Detection and Isolation from Swine

Surveillance for influenza A viruses in swine is critical to human and animal health because influenza A virus rapidly evolves in swine populations and new strains are continually emerging. Swine are able to be infected by diverse lineages of influenza A virus making them important hosts for the emergence and maintenance of novel influenza A virus strains. Sampling pigs in diverse settings such as commercial swine farms, agricultural fairs, and live animal markets is important to provide a comprehensive view of currently circulating IAV strains. The current gold-standard ante-mortem sampling technique (i.e. collection of nasal swabs) is labor intensive because it requires physical restraint of the pigs. Nasal wipes involve rubbing a piece of fabric across the snout of the pig with minimal to no restraint of the animal. The nasal wipe procedure is simple to perform and does not require personnel with professional veterinary or animal handling training. While slightly less sensitive than nasal swabs, virus detection and isolation rates are adequate to make nasal wipes a viable alternative for sampling individual pigs when low stress sampling methods are required. The proceeding protocol outlines the steps needed to collect a viable nasal wipe from an individual pig.

The authors present a protocol to collect swine nasal wipes to detect and isolate influenza A viruses.

鼻湿巾从猪流感病毒检测和​​隔离

Surveillance for influenza A viruses in swine is critical to human and animal health because influenza A virus rapidly evolves in swine populations and ...

Measuring Attachment and Internalization of Influenza A Virus in A549 Cells by Flow Cytometry

Attachment to target cells followed by internalization are the very first steps of the life cycle of influenza A virus (IAV). We provide here a detailed protocol for measuring relative changes in the amount of viral particles that attach to A549 cells, a human lung epithelial cell line, as well as in the amount of particles that are internalized into the cell. We use biotinylated virus which can be easily detected following staining with Cy3-labeled streptavidin (STV-Cy3). We describe the growth, purification and biotinylation of A/WSN/33, a widely used IAV laboratory strain. Cold-bound biotinylated IAV particles on A549 cells are stained with STV-Cy3 and measured using flow cytometry. To investigate uptake of viral particles, cold-bound virus is allowed to internalize at 37 &#176;C. In order to differentiate between external and internalized viral particles, a blocking step is applied: Free binding spots on the biotin of attached virus on the cell surface are bound by unlabeled streptavidin (STV). Subsequent cell permeabilization and staining with STV-Cy3 then enables detection of internalized viral particles. We present a calculation to determine the relative amount of internalized virus. This assay is suitable to measure effects of drug-treatments or other manipulations on attachment or internalization of IAV.

We present a protocol describing a semi-quantitative method for measuring both, the attachment of influenza A virus to A549 cells, as well as the internalization of virus particles into the target cells by flow cytometry.

通过流式细胞仪测量附件和流感的内在病毒在A549细胞

Attachment to target cells followed by internalization are the very first steps of the life cycle of influenza A virus (IAV). We provide here a detailed ...

Neutrophil Isolation and Analysis to Determine their Role in Lymphoma Cell Sensitivity to Therapeutic Agents

Neutrophils are the most abundant (40% to 75%) type of white blood cells and among the first inflammatory cells to migrate towards the site of inflammation. They are key players in the innate immune system and play major roles in cancer biology. Neutrophils have been proposed as key mediators of malignant transformation, tumor progression, angiogenesis and in the modulation of the antitumor immunity; through their release of soluble factors or their interaction with tumor cells. To characterize the specific functions of neutrophils, a fast and reliable method is coveted for in vitro isolation of neutrophils from human blood. Here, a density gradient separation method is demonstrated to isolate neutrophils as well as mononuclear cells from the blood. The procedure consists of layering the density gradient solution such as Ficoll carefully above the diluted blood obtained from patients diagnosed with chronic lymphocytic leukemia (CLL), followed by centrifugation, isolation of mononuclear layer, separation of neutrophils from RBCsby dextran then lysis of residual erythrocytes. This method has been shown to isolate neutrophils &#8805; 90 % pure. To mimic the tumor microenvironment, 3-dimensional (3D) experiments were performed using basement membrane matrix such as Matrigel. Given the short half-life of neutrophils in vitro, 3D experiments with fresh human neutrophils cannot be performed. For this reason promyelocytic HL60 cells are differentiated along the granulocytic pathway using the differentiation inducers dimethyl sulfoxide (DMSO) and retinoic acid (RA). The aim of our experiments is to study the role of neutrophils on the sensitivity of lymphoma cells to anti-lymphoma agents. However these methods can be generalized to study the interactions of neutrophils or neutrophil-like cells with a large range of cell types in different situations.

Neutrophils are the most abundant type of white blood cells. The isolation of neutrophils from human blood by density gradient separation method and the differentiation of human promyelocytic (HL60) cells along the granulocytic pathway are described here; to test their role on sensitivity of lymphoma cells to anti-lymphoma agents.

中性粒细胞分离和分析，以确定他们的淋巴瘤细胞的敏感性对治疗药物的作用

Neutrophils are the most abundant (40% to 75%) type of white blood cells and among the first inflammatory cells to migrate towards the site of ...

In Vitro Disassembly of Influenza A Virus Capsids by Gradient Centrifugation

Acid-triggered molecular processes closely control cell entry of many viruses that enter through the endocytic system. In the case of influenza A virus (IAV), virus fusion with the endosomal membrane as well as the subsequent disassembly of the viral capsid, called uncoating, is governed by the ionic conditions inside endocytic vesicles. The early steps in the virus life cycle are hard to study because endosomes cannot be directly accessed experimentally, creating the need for an in vitro approach. Here, we describe a method based on velocity gradient centrifugation of purified virions through a two-layer glycerol gradient, which enables analysis of the IAV core and its stability. The gradient contains a non-ionic detergent (NP-40) in its lower layer to remove the viral membrane by solubilization as the virus sediments toward the bottom. At neutral pH, viral cores are pelleted as stable structures. The major core components, matrix protein (M1) and the viral ribonucleoproteins (vRNPs), can be clearly identified in the pellet fraction by SDS-PAGE. Decreasing the pH to 6.0 or lower in the bottom layer selectively removes M1 from the pellet followed by release of vRNPs at more acidic conditions. Viral protein bands on Coomassie-stained gels can be subjected to densitometric quantification to monitor intermediate states of IAV disassembly. Besides pH, other factors that influence viral core stability can be assessed, such as salt concentration and putative viral uncoating factors, simply by modifying the detergent-containing glycerol layer accordingly. Taken together, the presented technique allows highly reproducible and quantitative analysis of viral uncoating in vitro. It can be applied to other enveloped viruses that undergo complex uncoating processes.

In Vitro Disassembly of Influenza A Virus Capsids by Gradient Centrifugation

Disassembly of influenza A virus cores during virus entry into host cells is a multistep process. We describe an in vitro method to analyze the early stages of viral uncoating. In this approach, velocity gradient centrifugation is used to biochemically dissect the steps that initiate uncoating under defined conditions.

在甲型流感病毒的衣壳的体外拆卸梯度离心

Acid-triggered molecular processes closely control cell entry of many viruses that enter through the endocytic system. In the case of influenza A virus ...

Influenza A Virus Studies in a Mouse Model of Infection

Influenza viruses cause over 500,000 deaths worldwide1 and are associated with an annual cost of 12 - 14 billion USD in the United States alone considering direct medical and hospitalization expenses and work absenteeism2. Animal models are crucial in Influenza A virus (IAV) studies to evaluate viral pathogenesis, host-pathogen interactions, immune responses, and the efficacy of current and/or novel vaccine approaches as well as antivirals. Mice are an advantageous small animal model because their immune system is evolutionarily similar to that found in humans, they are available from commercial vendors as genetically identical subjects, there are multiple strains that can be exploited to evaluate the genetic basis of infections, and they are relatively inexpensive and easy to manipulate. To recapitulate IAV infection in humans via the airways, mice are first anesthetized prior to intranasal inoculation with infectious IAVs under proper biosafety containment. After infection, the pathogenesis of IAVs is determined by monitoring daily the morbidity (body weight loss) and mortality (survival) rate. In addition, viral pathogenesis can also be evaluated by assessing virus replication in the upper (nasal mucosa) or lower (lungs) respiratory tract of infected mice. Humoral responses upon IAV infection can be rapidly evaluated by non-invasive bleeding and secondary antibody detection assays aimed at detecting the presence of total or neutralizing antibodies. Here, we describe the common methods used to infect mice intranasally (i.n) with IAV and evaluate pathogenesis, humoral immune responses and protection efficacy.

Influenza A viruses (IAVs) are important human respiratory pathogens. To understand the pathogenicity of IAVs and to perform preclinical testing of novel vaccine approaches, animal models mimicking human physiology are required. Here, we describe techniques to evaluate IAV pathogenesis, humoral responses and vaccine efficacy using a mouse model of infection.