Name: preparation of pseudo-typed h5 avian influenza viruses with calcium phosphate transfection method and measurement of antibody neutralizing activity
Uploaded: 2021-11-22T13:30:00
Description: Watch this Scientific Journal Video about Preparation of Pseudo-Typed H5 Avian Influenza Viruses with Calcium Phosphate Transfection Method and Measurement of Antibody Neutralizing Activity at JoVE.co

这项工作得到了江苏省创新能力建设项目（BM2020019）和深圳市科技项目（No.JSGG20200225150702770）、中国科学院战略重点研究计划（XDB29030103）、广东省科技计划（编号：2020B1111340076）和深圳湾实验室开放研究计划（编号：2020B1111340076）。SZBL202002271003）。

所有假病毒相关实验操作均在中国科学院上海巴斯德研究所（IPS，CAS）的ABSL2条件下进行。动物实验是根据机构动物护理和使用委员会批准的IPS，CAS动物方案进行的。
1. 磷酸钙转染假病毒包装
<ol><li>在完整的DMEM培养基中制备HEK293FT细胞的单细胞悬液（每毫升9 x 105）（表1）。将10mL单细胞悬液加入T75烧瓶中，在转染前将细胞在37°C，5%二氧化碳...

<ol>
	<li>Wang, G., 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=DNA+prime+and+virus-like+particle+boost+from+a+single+H5N1+strain+elicits+broadly+neutralizing+antibody+responses+against+head+region+of+h5+hemagglutinin.">DNA prime and virus-like particle boost from a single H5N1 strain elicits broadly neutralizing antibody responses against head region of h5 hemagglutinin.</a> The Journal of Infectious Diseases. 209 (5), 676-685 (2014).</li><li>Wang, G., Yin, R., Zhou, P., Ding, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combination+of+the+immunization+with+the+sequence+close+to+the+consensus+sequence+and+two+DNA+prime+plus+one+VLP+boost+generate+H5+hemagglutinin+specific+broad+neutralizing+antibodies.">Combination of the immunization with the sequence close to the consensus sequence and two DNA prime plus one VLP boost generate H5 hemagglutinin specific broad neutralizing antibodies.</a> Plos One. 12 (5), 0176854 (2017).</li><li>Li, Q., Liu, Q., Huang, W., Li, X., Wang, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Current+status+on+the+development+of+pseudoviruses+for+enveloped+viruses.">Current status on the development of pseudoviruses for enveloped viruses.</a> Reviews in Medical Virology. 28 (1), 1963 (2018).</li><li>Duverg&#233;, A., Negroni, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pseudotyping+lentiviral+vectors:+When+the+clothes+make+the+virus.">Pseudotyping lentiviral vectors: When the clothes make the virus.</a> Viruses. 12 (11), 1311 (2020).</li><li>Carnell, G. W., Ferrara, F., Grehan, K., Thompson, C. P., Temperton, N. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pseudotype-based+neutralization+assays+for+influenza:+A+systematic+analysis.">Pseudotype-based neutralization assays for influenza: A systematic analysis.</a> Frontiers in Immunology. 6 (161), (2015).</li><li>Trombetta, C., Perini, D., Mather, S., Temperton, N., Montomoli, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Overview+of+serological+techniques+for+influenza+vaccine+evaluation:+Past,+present+and+future.">Overview of serological techniques for influenza vaccine evaluation: Past, present and future.</a> Vaccines. 2 (4), 707-734 (2014).</li><li>Wei, C. J., 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=Next-generation+influenza+vaccines:+opportunities+and+challenges.">Next-generation influenza vaccines: opportunities and challenges.</a> Nature Reviews Drug Discovery. 19 (4), 239-252 (2020).</li><li>Krammer, F., 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=Influenza.">Influenza.</a> Nature Reviews Disease Primers. 4 (3), (2018).</li><li>Wei, C. J., 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=Induction+of+broadly+neutralizing+H1N1+influenza+antibodies+by+vaccination.">Induction of broadly neutralizing H1N1 influenza antibodies by vaccination.</a> Science. 27 (329), 1060-1064 (2010).</li><li>Chernov, V. M., Chernova, O. A., Sanchez-Vega, J. T., Kolpakov, A. I., Ilinskaya, O. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mycoplasma+contamination+of+cell+cultures+vesicular+traffic+in+bacteria+and+control+over+infectious+agents.">Mycoplasma contamination of cell cultures vesicular traffic in bacteria and control over infectious agents.</a> Acta Naturae. 6 (3), 41-51 (2014).</li><li>Michael, R. G., Joseph, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Molecular Cloning: A Laboratory Manual (Fourth Edition). , (2012).</li><li>Kumar, P., Nagarajan, A., Uchil, P. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transfection+of+mammalian+cells+with+calcium+phosphate-DNA+coprecipitates.">Transfection of mammalian cells with calcium phosphate-DNA coprecipitates.</a> Cold Spring Harbor Protocols. 2019 (10), (2019).</li><li>Robert, E. K., Chen, C. A., Okayama, H., John, K. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Calcium+phosphate+transfection.">Calcium phosphate transfection.</a> Current Protocols in Molecular Biology. 9, (2003).</li><li>Robert, E. K., Chen, C. A., Okayama, H., John, K. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transfection+of+DNA+into+eukaryotic+cells.">Transfection of DNA into eukaryotic cells.</a> Current Protocols in Molecular Biology. 9, 11-19 (1996).</li><li>Kachkin, D. V., Khorolskaya, J. I., Ivanova, J. S., Rubel, A. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+efficient+method+for+isolation+of+plasmid+DNA+for+transfection+of+mammalian+cell+cultures.">An efficient method for isolation of plasmid DNA for transfection of mammalian cell cultures.</a> Methods and Protocols. 3 (4), 69 (2020).</li><li>. Luciferase assay system Available from: <a target="_blank" href="https://www.promega.com.cn/products/luciferase-assays/reporter-assays/luciferase-assay-system">https://www.promega.com.cn/products/luciferase-assays/reporter-assays/luciferase-assay-system</a> (2021)</li><li>. Corning 96-Well Solid Black or White Polystyrene Microplates Available from: <a target="_blank" href="https://www.fishersci.com/shop/products/costar-96-well-black-white-solid-plates">https://www.fishersci.com/shop/products/costar-96-well-black-white-solid-plates</a> (2021)</li></ol>

HEK293FT细胞通常用作包装细胞以产生假病毒。在细胞培养过程中，定期检测支原体至关重要。支原体污染可大大降低假病毒产量，有时接近于零。与其他污染相比，支原体污染不会导致细胞培养基的pH值变化或浑浊。即使是高浓度的支原体，肉眼或显微镜下也看不到。三种常用的支原体检测方法是支原体培养、荧光 DAPI 或 Hoechst 33258 DNA 染色和聚合酶链反应 （PCR）。PCR扩增培养样品中的支原体DNA广?...

自1996年以来，A/goose/广东/1/96谱系高致病性禽流感（HPAI）H5病毒在家禽和野生鸟类中持续暴发流感，给全球家禽业造成了巨大的社会经济损失。有时，人类也会感染它，面临高死亡率1，2。然而，高致病性禽流感病毒研究往往受到阻碍，因为它不能在生物安全3级实验室之外处理。为了解决这个问题，在H5 HPAI研究的一些实验中，假病毒被采用作为野生型病毒的替代品。假病毒足够安全，可以在生物安全2级实验室进行实践。
H5 HPAI 假病毒属于嵌合病毒，由替代病毒核心、带有流感病毒表面糖蛋白的脂质包膜和报告基因组成。假病毒核心通常来源于慢病毒人类免疫缺陷病毒 （HIV）、逆转录病毒（如鼠白血病病毒 （MLV） 和水疱性口炎病毒 （VSV）3。具体来说，HIV-1包装系统被广泛用于产生流感假病毒，其中提供的主要基因是 gag 和 pol。HIVgag基因表达核心蛋白。pol基因表达整合酶和逆转录酶，这两者都是报告基因在转导细胞中表达所必需的。模仿替代病毒的基因组，报告基因以RNA形式被拥抱到假病毒核心中。报告基因将在宿主细胞中表达蛋白质。报告基因的基因表达水平可用于测量假病毒感染效率3，4。主要报告基因是萤火虫荧光素酶，用于测量转导细胞中的相对发光单位（RLU）或相对荧光素酶活性（RLA）。其他报告基因如lacZ，Gaussia和Renilla荧光素酶也被使用，只是程度较小5。
假病毒是研究针对H5 HAPI病毒的中和抗体的理想工具。为了测量中和抗体的效力，使用假病毒中和（PN）测定6。血凝素（HA）和神经氨酸酶（NA）是甲型流感病毒7，8表面的糖蛋白。HA由用于受体结合的球状头部结构域和用于膜融合的干结构域组成。NA蛋白具有促进病毒释放的唾液酸酶活性7，8。PN 测定可以测量针对 HA 蛋白的中和抗体。针对HA头部和茎区域的中和抗体也可以通过病毒附着和进入测定来检测。与野生型病毒相比，假病毒中和实验具有更灵敏的检测值，可以在2级生物安全实验室中安全处理，并且在实践中通常更容易操作。
该协议详细介绍了H5 HPAI假病毒制备和PN测定的程序和关键步骤。此外，它还讨论了这些测定的故障排除、限制和修改。本研究以H5N1高致病性禽流感病毒的A/Thailand/1（KAN）-1/2004（TH）毒株为例。为了获得测定中使用的免疫血清，该方案选择源自TH菌株的HA蛋白作为免疫原来免疫小鼠。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>1% Chiken Erythrocyte</td>
			<td>Bio-channel</td>
			<td>BC-RBC-C001</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>96-well cell culture plates (flat-bottom)</td>
			<td>Thermo fisher scientific</td>
			<td>167008</td>
			<td>consumable material</td>
		</tr>
		<tr>
			<td>96-well cell culture plates (round-bottom)</td>
			<td>Thermo fisher scientific</td>
			<td>163320</td>
			<td>consumable material</td>
		</tr>
		<tr>
			<td>Allegra X-15R</td>
			<td>Beckman coulter</td>
			<td>--</td>
			<td>Equipment/Centrifuge</td>
		</tr>
		<tr>
			<td>BD Insulin Syringes</td>
			<td>BD</td>
			<td>324910</td>
			<td>consumable material</td>
		</tr>
		<tr>
			<td>Calcium Chloride Anhydrous</td>
			<td>AMRESCO</td>
			<td>1B1110-500G</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>chloroquine diphosphate</td>
			<td>Selleck</td>
			<td>S4157</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Dulbecco&#8217;s Modified Eagle Medium (DMEM)</td>
			<td>Gibco</td>
			<td>12100-046</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum</td>
			<td>Gibco</td>
			<td>16000-044</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>HEK293FT</td>
			<td>Gibco</td>
			<td>R700-07</td>
			<td>Cell line</td>
		</tr>
		<tr>
			<td>HEPES FREE ACID</td>
			<td>AMRESCO</td>
			<td>0511-250G</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>HIV-1 p24 Antigen ELISA</td>
			<td>ZeptoMetrix</td>
			<td>801111</td>
			<td>Reagent kit</td>
		</tr>
		<tr>
			<td>Luciferase Assay System Freezer Pack</td>
			<td>Promega</td>
			<td>E4530</td>
			<td>Reagent kit</td>
		</tr>
		<tr>
			<td>MDCK.1</td>
			<td>ATCC</td>
			<td>CRL-2935</td>
			<td>Cell line</td>
		</tr>
		<tr>
			<td>Microcentrifuge Tubes 1.5 mL</td>
			<td>Thermo fisher scientific</td>
			<td>509-GRD-Q</td>
			<td>consumable material</td>
		</tr>
		<tr>
			<td>Nunc Conical Centrifuge Tubes 15 mL</td>
			<td>Thermo fisher scientific</td>
			<td>339650</td>
			<td>consumable material</td>
		</tr>
		<tr>
			<td>Nunc Conical Centrifuge Tubes 50 mL</td>
			<td>Thermo fisher scientific</td>
			<td>339652</td>
			<td>consumable material</td>
		</tr>
		<tr>
			<td>Nunc EasYFlask 75 cm2</td>
			<td>Thermo fisher scientific</td>
			<td>156499</td>
			<td>consumable material</td>
		</tr>
		<tr>
			<td>Penicillin-Streptomycin</td>
			<td>Gibco</td>
			<td>15140-122</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Pipette Tips (10 &#956;L)</td>
			<td>Thermo fisher scientific</td>
			<td>TF102-10-Q</td>
			<td>consumable material</td>
		</tr>
		<tr>
			<td>Pipette Tips (100 &#956;L)</td>
			<td>Thermo fisher scientific</td>
			<td>TF113-100-Q</td>
			<td>consumable material</td>
		</tr>
		<tr>
			<td>Pipette Tips (1000 &#956;L)</td>
			<td>Thermo fisher scientific</td>
			<td>TF112-1000-Q</td>
			<td>consumable material</td>
		</tr>
		<tr>
			<td>Serological pipets (5 mL)</td>
			<td>Thermo fisher scientific</td>
			<td>170355N</td>
			<td>consumable material</td>
		</tr>
		<tr>
			<td>Serological pipets (10 mL)</td>
			<td>Thermo fisher scientific</td>
			<td>170356N</td>
			<td>consumable material</td>
		</tr>
		<tr>
			<td>Trypsin/EDTA</td>
			<td>Gibco</td>
			<td>25200-072</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Varioskan Flash</td>
			<td>Thermo fisher scientific</td>
			<td>--</td>
			<td>Equipment/Microplate reader</td>
		</tr>
		<tr>
			<td>Water Jacket Incubator</td>
			<td>Thermo fisher scientific</td>
			<td>3111</td>
			<td>Equipment/Cell incubator</td>
		</tr>
		<tr>
			<td>Pentobarbital sodium salt</td>
			<td>Sigma</td>
			<td>57-33-0</td>
			<td>Reagent</td>
		</tr>
	</tbody>
</table>

preparation of pseudo-typed h5 avian influenza viruses with calcium phosphate transfection method and measurement of antibody neutralizing activity

自1996年以来，A/Goose/广东/1/96谱系高致病性禽流感（HPAI）H5病毒一直在家禽和野生鸟类中引起流感疫情。有时，人类也会成为它的受害者，从而导致高死亡率。尽管如此，高致病性禽流感病毒研究往往受到阻碍，因为它必须在生物安全3级实验室内处理。为了解决这个问题，在H5 HPAI研究的一些实验中，假病毒被采用作为野生型病毒的替代品。假病毒被证明是研究针对 H5 HPAI 病毒的中和抗体的理想工具。该协议描述了H5 HPAI假病毒制备和假病毒中和测定的程序和关键步骤。此外，它还讨论了这些测定的故障排除、限制和修改。

流感假病毒的HA、NA和HIV-1 p24蛋白表达 为了确定病毒包装效率，首先通过HA测定检测流感假病毒储液（图2A）。每毫升流感假病毒的HA单位为643（表3）。蛋白质印迹测定和夹心ELISA测定用于测试HA，NA和HIV-1 p24蛋白表达。然后计算假病毒HA单位与gag p24量的比值。蛋白质印迹测定的结果表明有4种蛋白质类型：HA0，HA1，HA2和NA蛋白（补充图2）...

Watch this Scientific Journal Video about Preparation of Pseudo-Typed H5 Avian Influenza Viruses with Calcium Phosphate Transfection Method and Measurement of Antibody Neutralizing Activity at JoVE.co

Preparation of Pseudo-Typed H5 Avian Influenza Viruses with Calcium Phosphate Transfection Method and Measurement of Antibody Neutralizing Activity

在这里，我们描述了假病毒包装和抗体中和活性测量的协议。

磷酸钙转染法制备假型H5禽流感病毒及抗体中和活性测定

Since 1996, A/goose/Guangdong/1/96-lineage highly pathogenic avian influenza (HPAI) H5 viruses have been causing flu outbreaks in poultry and wild birds. ...

该协议描述了H5高病原体禽流感假病毒制剂和伪病毒中和测定的程序和关键步骤。此外，它还讨论了这些测定的故障排除限制和修改。高致病性病原体必须在三级生物安全实验室进行，而假病毒可以在二级生物安全实验室安全处理。首先，在完整的DMEM培养基中制作HEK293 FT细胞的单细胞悬液。将10毫升单细胞悬液加入T75烧瓶中，然后在37摄氏度下孵育。转染前两小时，用10毫升氯喹新鲜完全培养基替换旧培养基。按照手稿中的说明混合试剂和质粒DNA，然后将该混合物转移到细胞上方的培养基中并轻轻摇动。孵育后，用15毫升新鲜的完整DMEM培养基替换培养基。65小时后，通过离心收获上清液。收集上清液并等分。为了检测血凝素蛋白表达，将 50 微升 PBS 添加到 96 孔圆底板的第 2 列至第 12 列中。将100微升假病毒加入第一列的孔中。然后将50微升假病毒从第一列转移到第二列的孔中。进行这种双重稀释，直到第11列，然后轻轻混合。然后丢弃第 50 列中多余的 11 微升。向每个孔中加入50微升0.5%红细胞，然后轻轻混合。在室温下孵育30至60分钟后，观察并记录假病毒的血凝素滴度。对于假病毒滴定，在完整的DMEM培养基中制成每毫升MDCK细胞10至第四个细胞的5倍单细胞悬液。将 1， 250、2， 500、5， 000、10， 000、20， 000 和 40， 000 个细胞添加到平底 96 孔板的不同孔中。孵育后，解冻并涡旋假病毒。向96孔圆底板的每个孔中加入六个假病毒HAU，并用高达120微升的完整DMEM补充每个孔。将100微升混合物转移到96孔板中的细胞中。将培养板孵育 48、60 和 72 小时以感染病毒并进行荧光素酶测定。为了进行荧光素酶测定，通过小心地去除培养基并用200微升PBS冲洗来洗涤细胞。尽可能多地去除PBS，然后向每个孔中加入50毫升裂解缓冲液。第二天，在室温下平衡板两个小时，然后摇动培养板几次，并将所有细胞裂解物转移到不透明的96孔板中。向每个板中加入50微升基材并充分混合。使用光度计记录假病毒的荧光素酶滴度。将100微升MDCK细胞的单细胞悬液加入平底96孔板的每个孔中，并在37摄氏度下孵育20小时。孵育后，解冻并涡旋储存在零下80摄氏度的假病毒和血清。在完全培养基中稀释血清20倍。将 100 微升 DMEM 培养基添加到第 3 列至第 10 列中。将200微升稀释的血清加入第二柱的孔中并进行连续稀释。然后在第11列中加入100微升DMEM培养基作为阴性对照。向每个孔中加入100微升伪病毒并混合。将100微升混合物从96孔圆底板转移到96孔细胞培养板的相应孔中。在37摄氏度下孵育60小时后，进行荧光素酶测定。血凝素测定显示，流感假病毒库存中每毫升流感假病毒存在643个HA单位。HA和Gag P24的比率在正常范围内。蛋白质印迹测定显示存在四种蛋白质类型，包括HA0，HA1，HA2和NA蛋白，表明流感假病毒与野生型病毒相似。假病毒滴定结果表明，相对荧光素酶活性最高的合适条件包括在96孔板的孔中喂养5， 000个细胞，并在病毒感染60小时后检测相对荧光素酶活性读数。DDV组免疫血清对泰国1罐104株假病毒表现出较高的中和滴度，而对照组血清未表现出任何中和活性。与对照血清相比，免疫血清的中和活性有效，表明免疫血清中有许多抗体指向HA头部。在病毒进入评估期间，免疫血清和对照之间的显着差异表明抗体直接指向免疫血清中的HA干区域。执行此过程时，请记住保持转染溶液和培养基的pH值稳定。

Research

JoVE Journal

Immunology and Infection

Rapid Diagnosis of Avian Influenza Virus in Wild Birds: Use of a Portable rRT-PCR and Freeze-dried Reagents in the Field

在野生鸟类禽流感病毒快速诊断：使用便携式的RRT - PCR和在外地的冻干试剂

Wild birds have been implicated in the spread of highly pathogenic avian influenza (HPAI) of the H5N1 subtype, prompting surveillance along migratory ...

科研

免疫与感染

Avian Influenza Surveillance with FTA  Cards: Field Methods, Biosafety, and Transportation Issues Solved

禽流感监测与FTA卡：实地方法，生物安全，和运输问题解决了

Avian Influenza Viruses (AIVs) infect many mammals, including humans1. These AIVs are diverse in their natural hosts, harboring almost all possible viral ...

Determining the Phagocytic Activity of Clinical Antibody Samples

确定临床抗体样品的吞噬活性

Antibody-driven phagocytosis is induced via the engagement of Fc receptors on professional phagocytes, and can contribute to both clearance as well as ...

High-throughput Detection Method for Influenza Virus

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, ...

Measurement of Antibody Effects on Cellular Function of Isolated Cardiomyocytes

测量抗体乳鼠心肌细胞对细胞功能的影响

Dilated cardiomyopathy  (DCM) is one of the main causes for heart failure in younger adults1.  Although genetic disposition and exposition to toxic ...

Intranasal Administration of Recombinant Influenza Vaccines in Chimeric Mouse Models to Study Mucosal Immunity

重组流感疫苗的嵌合体小鼠模型鼻腔给药研究黏膜免疫

Vaccines are one of the greatest achievements of mankind, and have saved millions of lives over the last century. Paradoxically, little is known about the ...

Rapid Molecular Detection and Differentiation of Influenza Viruses A and B

快速分子检测和流感病毒A和B的分化

Influenza is a contagious respiratory illness caused by influenza viruses A and B in humans and causes a significant amount of morbidity and mortality ...

Measuring Influenza Neuraminidase Inhibition Antibody Titers by Enzyme-linked Lectin Assay

通过酶联凝集素测定来测量神经氨酸酶流感抑制抗体滴度

Antibodies to neuraminidase (NA), the second most abundant surface protein on influenza virus, contribute toward protection against influenza. Traditional ...

Measurement of In Vitro Integration Activity of HIV-1 Preintegration Complexes

Measurement of In Vitro Integration Activity of HIV-1 Preintegration Complexes

测量<em&gt;体外</em&gt; HIV-1 Preintegration配合物的整合活动

HIV-1 envelope proteins engage cognate receptors on the target cell surface, which leads to viral-cell membrane fusion followed by the release of the ...

Fluorescence-based Neuraminidase Inhibition Assay to Assess the Susceptibility of Influenza Viruses to The Neuraminidase Inhibitor Class of Antivirals

荧光为基础的神经氨酸酶抑制测定流感病毒的易感性评估抗病毒药的神经氨酸酶抑制剂类

The neuraminidase (NA) inhibitors are the only class of antivirals approved for the treatment and prophylaxis of influenza that are effective against ...