的承认通过国防部的资助，国会导演医学研究计划（＃W81XWH-10-1-0445），美国国立卫生研究院（NIH R21 HL110056），和美国心脏协会（＃11SDG4890030）。

1。缓冲器和测试代理的制备和消毒<ol><li> 150mM NaCl的缓冲液：溶解在500毫升水nanopure4.383克NaCl的晶体。 </li><li> pH缓冲液：准备在pH为5.6，6.2，6.8和7.4的磷酸盐缓冲液混合适量的一元和二元磷酸钠。如果样品是在较低的pH值（ 即pH &lt;5.6），然后一个更合适的缓冲液，如柠檬酸盐缓冲液进行测试，应该被使用。缓冲液配方都是现成的，这里提供了一个例子参考。 </li><li>消毒瓶顶真空过滤装置，并重新检查缓冲液通过上面提到的所有缓冲区。 </li><li> 20％的Triton X-100（阳性对照）：混合20毫升纯的Triton X-100在80毫升水nanopure。涡大力超声溶解。发布在使用前在室温下过夜。 </li></ol> 2。红细胞制备<ol><li>获得25毫升的血液FROM一个匿名的人的捐助，直接绘制到K-EDTA涂层Vacutainer管，以防血液凝结。 </li></ol> 注意：所有程序必须事先批准的适当的机构审查委员会（IRB），静脉穿刺采血必须由经过培训的抽血以捐赠者的风险降到最低。标准放血程序已在其他地方发表。 <ol start="2"><li>离心血在500×g离心5分钟，和标记的血细胞比容水平（红色，下层）和血浆（微黄，上层）上管。 </li><li> 通过微量移液器轻轻吸出血浆，添加漂白剂，生物危险性废物丢弃到。 </li><li>用150mM NaCl溶液填充的血细胞比容管，标记线（原件的血浆水平）。盖上盖子，颠倒几次，轻轻拌匀。 500×g离心5分钟离心。 </li><li>重复步骤2.3-2.4再次洗血细胞。然后吸超自然蚂蚁和更换PBS在pH值7.4。反相，混合。 </li><li>斯普利特血液均匀地进入四根管，对应于将被测试的每个pH。标签的管，根据每个以进行测试（5.6，6.2，6.8，7.4）的pH值。 </li><li>在500×g离心5分钟，离心血液试管。马克的水平上管，然后吸出上清液。 </li><li>填充适当的缓冲液的pH值（2.6）每管标线。 </li><li>出版商四个50毫升锥形管（每一个pH值至测试），以及移液管49毫升PBS适当的pH值到每个锥形管。 </li><li>成相应的管中加入1毫升的红细胞（相同的pH值）为1:50的稀释。目视检查稀释血液，应浑浊，解决不受干扰。如果没有颗粒的形式，细胞裂解。 </li></ol> 3。裂解含量96孔板安装和定量分析<ol><li>储备液的配制所有的实验给药制剂，在20倍所需的最终浓度（含量进行测试将10μl的药物输送剂+ 190μl稀释的红血细胞，导致原来的药物输送剂的1/20稀释到最终测试混合物中）。建议为20，100，和800微克/毫升的股票，从而导致在最终测试浓度的1，5，和40微克/毫升，分别。 </li><li>移液管将10μl成V形底96孔板的每个原液。为了达到最佳效果，加载每个样品一式三份或四份。 </li></ol> 注意：为便于，建议为每个pH值来进行测试，用每个样品（在每一浓度）加载在n = 3-4每板一个单独的96孔板中，应制备。 <ol start="3"><li>阳性对照孔，加10微升20％的Triton X-100。 </li><li>对于阴性对照孔，加入10μl磷酸缓冲液。使用相同的pH值的缓冲液，以进行测试。 </li><li>吸取190μL稀释的红细胞（2.10），每孔，确保细胞原液保持同质传输过程中。提示：使用多道移液器简化这一任务。 </li><li>在37℃下温育平板一小时（可选：使用轨道摇床或摇臂）。 </li><li>离心5分钟的板在500 XG颗粒完好红细胞的。注意：当从离心机除去板输送到下一步骤时，小心处理，某些不破坏细胞沉淀。 </li><li>使用多通道移液管，从每个孔中加入100μl的上清液转移到一个清晰的，平底96孔板中。注：如果将细胞沉淀的任何样品（）被意外干扰，一个可以重新离心板，然后继续进行，上清液转移。 </li><li>用酶标仪测量上清液的吸光度。需要注意的是，可以使用一定范围的波长（400 - 541纳米）。 </li></ol> 注意：不同的板块读者可能有不同的饱和点和敏感，因此在选择的波长为我asurements取决于是否从实验样品的溶血数据可以可靠地对最大溶血归洗涤剂处理所诱导的。这就要求精确测量的阳性对照样品的吸光率值。 <ol start="10"><li>使用Microsoft Excel或类似的数据分析软件，找到从每个pH值（步骤3.4）的阴性对照样品的背景吸光度读数的平均值。这样的背景下吸光度值减去所有其它样品进行测量，pH值。 </li><li>背景减法之后，发现阳性对照的平均吸光度，洗涤剂处理的样品（步骤3.3）。然后正常化所有的实验数据点，这意味着吸光度值，它应该代表100％溶血。最后，乘以每口井的100％计算％溶血发生在每一个人的洗涤剂控制。 </li></ol>

<ol>
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IRB的批准程序已经批准了涉及人类受试者的范德比尔特大学机构审查委员会（IRB议定书＃111251）。没有利益冲突的声明。

的pH响应性聚合物或其他代理设计用于endosomolytic功能可以迅速和有效地筛选的基础上裂解过程中遇到的内体，在pH值的红血细胞（ 图1，pH为6.8 -早 ​​期内体，pH值6.2 -晚期内含体，pH为5.6 -溶酶体）14-17 pH依赖性溶血已用于筛选进行调解内体释放的生物大分子的治疗药物（ 例如肽，的siRNA，反义寡核苷酸，蛋白质）的载流子的能力，并且该测定的结果，可以预测的性能?...

虽然有许多潜在的高影响力的治疗靶点在细胞内，细胞内输送的代理商带来了显着的挑战。通常，药物，尤其是生物制剂，被细胞内化，贩卖到囊泡，要么导致它们的内容通过内溶酶体途径降解，或穿梭出细胞通过胞吐作用。1在后者的方法中，内部的pH值囊泡酸化至约5-6，这是活性的酶的最佳pH值，在此室的功能，如溶菌酶2 最近，一些材料经过特别设计，以充分利用酸化胞浆内吞体，以方便他们的货物交付。这种方法的一个示例中使用合成的聚合物胶束的纳米粒子，其核心是在生理pH值（ 即 7.4），两性离子和电荷中性。然而，在pH 6.0- 6.5，聚合物成为质子化并购入的净正电荷，破坏了胶束的核心，和暴露的聚合物链段相互作用和破坏核内体膜。这项活动已经表明，以促进核内体逃逸的多肽和核酸为基础的疗法，让他们来访问他们的胞浆目标。3,4调解胞内逃生，破坏黏膜屏障的方法的例子包括“膜融合肽或介导膜融合或瞬态孔形成的蛋白质，可以在磷脂双分子层中。5均聚物的阴离子的烷基丙烯酸，如聚（丙基丙烯酸酸）是另一种被充分研究的方法，并且在这些聚合物中，羧酸侧基的质子化状态的决定过渡为疏水性，膜中断状态内溶酶体的pH值范围6,7。 一个有用的模型系统，为筛选endosomolytic行为是电子x体内pH-依赖的溶血试验。8在该模型系统中，红细胞膜的脂双层膜的替代品，包围内溶酶体囊泡作为。此一般化模型已被用于别人，到评估的endosomolytic的行为的细胞穿透肽和其它聚合物的基因传递系统。8-11在本实验中，在模仿在定义的pH值的缓冲液共孵育的人的红血细胞和试验材料胞外（7.4），早期内体（6.8），和晚期内溶酶体（&lt;6.8）的环境中。潜伏期过程中释放的血红蛋白的量进行定量的红血细胞溶解，其被归一化到在阳性对照样品用洗涤剂裂解释放血红蛋白量作为衡量。 从一个小型图书馆的潜在的endosomolytic测试材料筛选，可以推断出，不产生溶血的样品，在pH值7.4，但显着升高下摆olysis在pH &lt;6.5时，将是最有效的和细胞相容性的候选人胞浆药物递送。预计将保持惰性的，而不是不分青红皂白地破坏脂质双分子层膜（ 即可能导致细胞毒性），直到被暴露后的pH值下降到溶酶体内舱的内符合这些条件的材料。 在这个协议中，红细胞从人供体中分离，并在pH为5.6，6.2，6.8或7.4与实验endosomolytic药物输送剂共同孵育。完整的红细胞沉淀，上清液（含血红蛋白释放溶解红细胞） 经由板读数器（ 图1）为特征的血红蛋白的吸光度分析。

<table border="1"><tr><td> 的试剂的名称 </td><td> 公司 </td><td> 目录编号 </td><td> 评论（可选） </td></tr><tr><td> BD真空采血管 - K2EDTA Vacutainer管</td><td> Fisher Scientific则</td><td> 22-253-145 </td><td>对于血液采集</td></tr><tr><td> BD真空采血管采血针，20.5号</td><td> Fisher Scientific则</td><td> 02-665-31 </td><td>对于血液采集</td></tr><tr><td> BD真空管座/针适配器</td><td> Fisher Scientific则</td><td> 22-289-953 </td><td>对于血液采集</td></tr><tr><td> BD品牌异丙基酒精棉签</td><td> Fisher Scientific则</td><td> 13-680-63 </td><td>对于血液采集</td></tr><tr><td> BD真空采无乳胶止血带</td><td> Fisher Scientific则</td><td> 02-657-6 </td><td>对于血液采集</TD&gt; </tr><tr><td>盐酸（浓） </td><td> Fisher Scientific则</td><td> A144-500 </td><td>为了调整pH值的D-PBS。 </td></tr><tr><td>的Triton X-100的</td><td> Sigma-Aldrich公司</td><td> T8787 </td><td>阳性对照</td></tr><tr><td>的Dulbecco PBS </td><td> Invitrogen公司</td><td> 14190 </td><td></td></tr><tr><td> NALGENE MF75一次性使用无菌瓶顶过滤单元与SFCA膜</td><td> Fisher Scientific则</td><td> 09-740-44A </td><td></td></tr><tr><td> BD 96孔板，平底，组织培养处理的聚苯乙烯</td><td> Fisher Scientific则</td><td> 08-772-2C </td><td>对于板读取的测定结束时。 </td></tr><tr><td> BD 96孔板，圆底，组织培养处理的聚苯乙烯</td><td> Fisher Scientific则</td><td> 08-772-17 </td><td>孵化的红血细胞与实验药物。 </td></tr></表&gt;

ex vivo red blood cell hemolysis assay for the evaluation of ph-responsive endosomolytic agents for cytosolic delivery of biomacromolecular drugs

内溶酶体膜泡的磷脂双分子层构成，可以构成一道屏障，细胞内的目标提供生物药物。为了克服这个障碍，已设计了一些合成的药物载体积极破坏核内体膜，并提供货物进入细胞质。这里，我们描述的溶血测定，这可以用作快速，高通量筛选的细胞相容性和endosomolytic活性的细胞内的药物输送系统。 溶血试验，人的红血细胞和试验材料共同模仿细胞外的，早期内体，和晚期溶酶体内环境的定义的pH值的缓冲液中温育。颗粒完整的红血细胞的离心步骤之后，释放到培养基中的血红蛋白量的分光光度测定（405nm的为最佳的动态范围）。 ％的红血细胞破碎，然后相对于阳性对照SAMP量化LES用洗涤剂溶解。在该模型系统中，在红细胞膜的脂双层膜的替代品，包围内溶酶体囊泡作为。期望的结果是可以忽略不计的在生理pH（7.4）和pH约为5-6.8的溶酶体内pH值范围从鲁棒溶血溶血。

<html>通常情况下，表现出理想的pH-依赖的溶血行为的代理具有胞质交付药物，核酸，或其它生物活性分子的最高电位。描绘在图2中，在pH = 7.4，显示出最小的溶血，这是举例说明由Agent＃1，但在核内体内的pH值范围（&lt;6.5）的溶血行为急剧增加。有些剂可以表现出溶血行为的显着水平的在生理pH值范围（代理＃2（40微克/毫升）， 图2），这表明，这些药物可能不是血液相?...

Watch this Scientific Journal Video about Ex Vivo Red Blood Cell Hemolysis Assay for the Evaluation of pH-responsive Endosomolytic Agents for Cytosolic Delivery of Biomacromolecular Drugs at JoVE.com

Ex Vivo Red Blood Cell Hemolysis Assay for the Evaluation of pH-responsive Endosomolytic Agents for Cytosolic Delivery of Biomacromolecular Drugs

溶血试验可作为一种快速，高通量筛选，药物传递系统的细胞相容性和内货物配送endosomolytic活动的。该试验测量作为环境pH值的函数的红细胞膜的破坏。

体外红血细胞溶血含量的生物大分子药物的细胞内交货的评价的pH响应Endosomolytic代理

Phospholipid bilayers that constitute endo-lysosomal vesicles can pose a barrier to delivery of biologic drugs to intracellular targets. To overcome this ...

ex-vivo-red-blood-cell-hemolysis-assay-for-evaluation-ph-responsive

Research

JoVE Journal

Immunology and Infection

Ex Vivo Red Blood Cell Hemolysis Assay for the Evaluation of pH-responsive Endosomolytic Agents for Cytosolic Delivery of Biomacromolecular Drugs

34.0K 次观看.  Vanderbilt University. 溶血试验可作为一种快速，高通量筛选，药物传递系统的细胞相容性和内货物配送endosomolytic活动的。该试验测量作为环境pH值的函数的红细胞膜的破坏。

视频: Ex Vivo Red Blood Cell Hemolysis Assay for the Evaluation of pH-responsive Endosomolytic Agents for Cytosolic Delivery of Biomacromolecular Drugs

Introducing Shear Stress in the Study of Bacterial Adhesion

During bacterial infections a sequence of interactions occur between the pathogen and its host. Bacterial adhesion to the host cell surface is often the initial and determining step of the pathogenesis. Although experimentally adhesion is mostly studied in static conditions adhesion actually takes place in the presence of flowing liquid. First encounters between bacteria and their host often occur at the mucosal level, mouth, lung, gut, eye, etc. where mucus flows along the surface of epithelial cells. Later in infection, pathogens occasionally access the blood circulation causing life-threatening illnesses such as septicemia, sepsis and meningitis. A defining feature of these infections is the ability of these pathogens to interact with endothelial cells in presence of circulating blood. The presence of flowing liquid, mucus or blood for instance, determines adhesion because it generates a mechanical force on the pathogen. To characterize the effect of flowing liquid one usually refers to the notion of shear stress, which is the tangential force exerted per unit area by a fluid moving near a stationary wall, expressed in dynes/cm2. Intensities of shear stress vary widely according to the different vessels type, size, organ, location etc. (0-100 dynes/cm2). Circulation in capillaries can reach very low shear stress values and even temporarily stop during periods ranging between a few seconds to several minutes 1. On the other end of the spectrum shear stress in arterioles can reach 100 dynes/cm2 2. The impact of shear stress on different biological processes has been clearly demonstrated as for instance during the interaction of leukocytes with the endothelium 3. To take into account this mechanical parameter in the process of bacterial adhesion we took advantage of an experimental procedure based on the use of a disposable flow chamber 4. Host cells are grown in the flow chamber and fluorescent bacteria are introduced in the flow controlled by a syringe pump. We initially focused our investigations on the bacterial pathogen Neisseria meningitidis, a Gram-negative bacterium responsible for septicemia and meningitis. The procedure described here allowed us to study the impact of shear stress on the ability of the bacteria to: adhere to cells 1, to proliferate on the cell surface 5and to detach to colonize new sites 6 (Figure 1). Complementary technical information can be found in reference 7. Shear stress values presented here were chosen based on our previous experience1 and to represent values found in the literature. The protocol should be applicable to a wide range of pathogens with specific adjustments depending on the objectives of the study.

During the infection process, a key step is the adhesion of pathogens with host cells. In most instances this adhesion step occurs in the presence of mechanical stress generated by flowing liquid. We describe a technique that introduces shear stress as an important parameter in the study of bacterial adhesion.

在细菌粘附的研究剪应力

During bacterial infections a sequence of interactions occur between the pathogen and its host. Bacterial adhesion to the host cell surface is often the ...

科研

免疫与感染

A Quantitative Evaluation of Cell Migration by the Phagokinetic Track Motility Assay

Cellular motility is an important biological process for both unicellular and multicellular organisms. It is essential for movement of unicellular organisms towards a source of nutrients or away from unsuitable conditions, as well as in multicellular organisms for tissue development, immune surveillance and wound healing, just to mention a few roles1,2,3. Deregulation of this process can lead to serious neurological, cardiovascular and immunological diseases, as well as exacerbated tumor formation and spread4,5. Molecularly, actin polymerization and receptor recycling have been shown to play important roles in creating cellular extensions (lamellipodia), that drive the forward movement of the cell6,7,8. However, many biological questions about cell migration remain unanswered.
The central role for cellular motility in human health and disease underlines the importance of understanding the specific mechanisms involved in this process and makes accurate methods for evaluating cell motility particularly important. Microscopes are usually used to visualize the movement of cells. However, cells move rather slowly, making the quantitative measurement of cell migration a resource-consuming process requiring expensive cameras and software to create quantitative time-lapsed movies of motile cells. Therefore, the ability to perform a quantitative measurement of cell migration that is cost-effective, non-laborious, and that utilizes common laboratory equipment is a great need for many researchers.
The phagokinetic track motility assay utilizes the ability of a moving cell to clear gold particles from its path to create a measurable track on a colloidal gold-coated glass coverslip9,10. With the use of freely available software, multiple tracks can be evaluated for each treatment to accomplish statistical requirements. The assay can be utilized to assess motility of many cell types, such as cancer cells11,12, fibroblasts9, neutrophils13, skeletal muscle cells14, keratinocytes15, trophoblasts16, endothelial cells17, and monocytes10,18-22. The protocol involves the creation of slides coated with gold nanoparticles (Au&deg;) that are generated by a reduction of chloroauric acid (Au3+) by sodium citrate. This method was developed by Turkevich et al. in 195123 and then improved in the 1970s by Frens et al.24,25. As a result of this chemical reduction step, gold particles (10-20 nm in diameter) precipitate from the reaction mixture and can be applied to glass coverslips, which are then ready for use in cellular migration analyses9,26,27.
In general, the phagokinetic track motility assay is a quick, quantitative and easy measure of cellular motility. In addition, it can be utilized as a simple high-throughput assay, for use with cell types that are not amenable to time-lapsed imaging, as well as other uses depending on the needs of the researcher. Together, the ability to quantitatively measure cellular motility of multiple cell types without the need for expensive microscopes and software, along with the use of common laboratory equipment and chemicals, make the phagokinetic track motility assay a solid choice for scientists with an interest in understanding cellular motility.

The phagokinetic motility track assay is a method used to assess the movement of cells. Specifically, the assay measures chemokinesis (random cell motility) over time in a quantitative manner. The assay takes advantage of the ability of cells to create a measurable track of their movement on colloidal gold-coated coverslips.

细胞迁移的的Phagokinetic轨道运动MLCK的定量评价

Cellular motility is an important biological process for both unicellular and multicellular organisms. It is essential for movement of unicellular ...

Antigens Protected Functional Red Blood Cells By The Membrane Grafting Of Compact Hyperbranched Polyglycerols

Red blood cell (RBC) transfusion is vital for the treatment of a number of acute and chronic medical problems such as thalassemia major and sickle cell anemia 1-3. Due to the presence of multitude of antigens on the RBC surface (~308 known antigens 4), patients in the chronic blood transfusion therapy develop alloantibodies due to the miss match of minor antigens on transfused RBCs 4, 5. Grafting of hydrophilic polymers such as polyethylene glycol (PEG) and hyperbranched polyglycerol (HPG) forms an exclusion layer on RBC membrane that prevents the interaction of antibodies with surface antigens without affecting the passage of small molecules such as oxygen ,glucose, and ions3. At present no method is available for the generation of universal red blood donor cells in part because of the daunting challenge presented by the presence of large number of antigens (protein and carbohydrate based) on the RBC surface and the development of such methods will significantly improve transfusion safety, and dramatically improve the availability and use of RBCs. In this report, the experiments that are used to develop antigen protected functional RBCs by the membrane grafting of HPG and their characterization are presented. HPGs are highly biocompatible compact polymers 6, 7, and are expected to be located within the cell glycocalyx that surrounds the lipid membrane 8, 9 and mask RBC surface antigens10, 11.

The cell membrane modification of red blood cells (RBCs) with hyperbranched polyglycerol (HPG) is presented. Modified RBCs were characterized by aqueous two phase partitioning, osmotic fragility and complement mediated lysis. The camouflage of surface proteins and antigens was evaluated using the flow cytometry and Micro Typing System (MTS) blood phenotyping cards.

紧凑型超支化聚乙二醇接枝的膜抗原受保护的功能性红血细胞

Red blood cell (RBC) transfusion is vital for the treatment of a number of acute and chronic medical problems such as thalassemia major and sickle cell ...

Methods for Quantitative Detection of Antibody-induced Complement Activation on Red Blood Cells

Antibodies against red blood cells (RBCs) can lead to complement activation resulting in an accelerated clearance via complement receptors in the liver (extravascular hemolysis) or leading to intravascular lysis of RBCs. Alloantibodies (e.g. ABO) or autoantibodies to RBC antigens (as seen in autoimmune hemolytic anemia, AIHA) leading to complement activation are potentially harmful and can be - especially when leading to intravascular lysis - fatal1. Currently, complement activation due to (auto)-antibodies on RBCs is assessed in vitro by using the Coombs test reflecting complement deposition on RBC or by a nonquantitative hemolytic assay reflecting RBC lysis1-4. However, to assess the efficacy of complement inhibitors, it is mandatory to have quantitative techniques. Here we describe two such techniques. First, an assay to detect C3 and C4 deposition on red blood cells that is induced by antibodies in patient serum is presented. For this, FACS analysis is used with fluorescently labeled anti-C3 or anti-C4 antibodies. Next, a quantitative hemolytic assay is described. In this assay, complement-mediated hemolysis induced by patient serum is measured making use of spectrophotometric&#160;detection of the released hemoglobin. Both of these assays are very reproducible and quantitative, facilitating studies of antibody-induced complement activation.

Here we describe two assays for measuring complement activation induced by antibodies against red blood cells. The major advantage over the current assays is their quantitative and easy-to-interpret nature.

定量检测抗体诱导补体激活的方法对红血细胞

Antibodies against red blood cells (RBCs) can lead to complement activation resulting in an accelerated clearance via complement receptors in the liver ...

High-throughput Quantitative Real-time RT-PCR Assay for Determining Expression Profiles of Types I and III Interferon Subtypes

Described in this report is a qRT-PCR assay for the analysis of seventeen human IFN subtypes in a 384-well plate format that incorporates highly specific locked nucleic acid (LNA) and molecular beacon (MB) probes, transcript standards, automated multichannel pipetting, and plate drying. Determining expression among the type I interferons (IFN), especially the twelve IFN-&#945; subtypes, is limited by their shared sequence identity; likewise, the sequences of the type III IFN, especially IFN-&#955;2 and -&#955;3, are highly similar. This assay provides a reliable, reproducible, and relatively inexpensive means to analyze the expression of the seventeen interferon subtype transcripts.

This protocol describes a high-throughput qRT-PCR assay for the analysis of type I and III IFN expression signatures. The assay discriminates single base pair differences between the highly similar transcripts of these genes. Through batch assembly and robotic pipetting, the assays are consistent and reproducible.

高通量实时定量RT-PCR检测方法的确定I型和III型干扰素亚型的表达谱

Described in this report is a qRT-PCR assay for the analysis of seventeen human IFN subtypes in a 384-well plate format that incorporates highly specific ...

Use of a Monocyte Monolayer Assay to Evaluate Fc&#947; Receptor-mediated Phagocytosis

Although originally developed for predicting transfusion outcomes of serologically incompatible blood, the monocyte monolayer assay (MMA) is a highly versatile in vitro assay that can be modified to examine different aspects of antibody and Fc&#947; receptor (Fc&#947;R)-mediated phagocytosis in both research and clinical settings. The assay utilizes adherent monocytes from peripheral blood mononuclear cells isolated from mammalian whole blood. MMA has been described for use in both human and murine investigations. These monocytes express Fc&#947;Rs (e.g., Fc&#947;RI, Fc&#947;RIIA, Fc&#947;RIIB, and Fc&#947;RIIIA) that are involved in immune responses. The MMA exploits the mechanism of Fc&#947;R-mediated interactions, phagocytosis in particular, where antibody-sensitized red blood cells (RBCs) adhere to and/or activate Fc&#947;Rs and are subsequently phagocytosed by the monocytes. In vivo, primarily tissue macrophages found in the spleen and liver carry out Fc&#947;R-mediated phagocytosis of antibody-opsonized RBCs, causing extravascular hemolysis. By evaluating the level of phagocytosis using the MMA, different aspects of the in vivo Fc&#947;R-mediated process can be investigated. Some applications of the MMA include predicting the clinical relevance of allo- or autoantibodies in a transfusion setting, assessing candidate drugs that promote or inhibit phagocytosis, and combining the assay with fluorescent microscopy or traditional Western immunoblotting to investigate the downstream signaling effects of Fc&#947;R-engaging drugs or antibodies. Some limitations include the laboriousness of this technique, which takes a full day from start to finish, and the requirement of research ethics approval in order to work with mammalian blood. However, with diligence and adequate training, the MMA results can be obtained within a 24-h turnover time.

Use of a Monocyte Monolayer Assay to Evaluate Fc&amp;#947; Receptor-mediated Phagocytosis

The monocyte monolayer assay (MMA) is an in vitro assay that utilizes isolated primary monocytes obtained from mammalian peripheral whole blood to evaluate Fc&#947; receptor (Fc&#947;R)-mediated phagocytosis.

单核细胞单层试验中用于评估Fcγ受体介导的吞噬作用

Although originally developed for predicting transfusion outcomes of serologically incompatible blood, the monocyte monolayer assay (MMA) is a highly ...

Dextran Enhances the Lentiviral Transduction Efficiency of Murine and Human Primary NK Cells

The efficient transduction of specific genes into natural killer (NK) cells has been a major challenge. Successful transductions are critical to defining the role of the gene of interest in the development, differentiation, and function of NK cells. Recent advances related to chimeric antigen receptors (CARs) in cancer immunotherapy accentuate the need for an efficient method to deliver exogenous genes to effector lymphocytes. The efficiencies of lentiviral-mediated gene transductions into primary human or mouse NK cells remain significantly low, which is a major limiting factor. Recent advances using cationic polymers, such as polybrene, show an improved gene transduction efficiency in T cells. However, these products failed to improve the transduction efficiencies of NK cells. This work shows that dextran, a branched glucan polysaccharide, significantly improves the transduction efficiency of human and mouse primary NK cells. This highly reproducible transduction methodology provides a competent tool for transducing human primary NK cells, which can vastly improve clinical gene delivery applications and thus NK cell-based cancer immunotherapy.

The goal of this study was to formulate technologies that allow for successful gene transduction in primary natural killer (NK) cells. The dextran-mediated lentiviral transduction of human or mouse primary NK cells results in higher gene expression efficiencies. This method of gene transduction will vastly improve NK cell genetic manipulation.

葡聚糖增强小鼠和人原发性 NK 细胞的慢转导效率

The efficient transduction of specific genes into natural killer (NK) cells has been a major challenge. Successful transductions are critical to defining ...

A Simple Red Blood Cell Lysis Method for the Establishment of B Lymphoblastoid Cell Lines

A number of methods exist for the transformation of B lymphocytes by the Epstein Barr virus in vitro into immortalized cell lines. We have developed a new method with a powerful and simple strategy for the establishment of B-LCLs, the red blood cell lysis method. This method simplified the PBMC separation procedure with red blood cell removal, and used as little as 0.5 mL of whole blood for establishing EBV-immortalized cell lines, which can proliferate to large cell numbers in a relatively short amount time with a 100% success rate. The method is simple, reliable, time saving, and applicable to treating a large number of the clinical samples.

A simple red blood cell lysis method for establishing B-LCLs was developed with high immortalization efficiency, requiring a small amount of blood and saving time from initiation to cryopreservation.

一个简单的红细胞溶解法对B淋巴母细胞系的建立

A number of methods exist for the transformation of B lymphocytes by the Epstein Barr virus in vitro into immortalized cell lines. We have developed a new ...

In Vivo Assay for Detection of Antigen-specific T-cell Cytolytic Function Using a Vaccination Model

Current methodologies for antigen-specific killing are limited to in vitro use or utilized in infectious disease models. However, there is not a protocol specifically intended to measure antigen-specific killing without an infection. This protocol is designed and describes methods to overcome these limitations by allowing for the detection of antigen-specific killing of a target cell by CD8+ T cells in vivo. This is accomplished by merging a vaccination model with a traditional CFSE-labeled target killing assay. This combination allows the researcher to assess the antigen-specific CTL potential directly and quickly as the assay is not dependent upon tumor growth or infection. In addition, the readout is based on flow cytometry and so should be readily accessible to most researchers. The major limitation of the study is identifying the timeline in vivo that is appropriate to the hypothesis being tested. Variations in antigen strength and mutations in the T cells that may result in differential cytolytic function need to be carefully assessed to determine the optimal time for cell harvest and assessment. The appropriate concentration of peptide for vaccination has been optimized for hgp10025-33 and OVA257-264, but further validation would be needed for other peptides that may be more appropriate to a given study. Overall, this protocol allows a quick assessment of killing function in vivo and can be adapted to any given antigen.

In Vivo Assay for Detection of Antigen-specific T-cell Cytolytic Function Using a Vaccination Model

The goal of this protocol is to allow for detection of in vivo antigen-specific killing of a target cell in a murine model.

在体内应用免疫模型检测抗原特异性 T 细胞细胞功能的试验

Current methodologies for antigen-specific killing are limited to in vitro use or utilized in infectious disease models. However, there is not a protocol ...

Measuring Deformability and Red Cell Heterogeneity in Blood by Ektacytometry

Decreased red cell deformability is characteristic of several disorders. In some cases, the extent of defective deformability can predict severity of disease or occurrence of serious complications. Ektacytometry uses laser diffraction viscometry to measure the deformability of red blood cells subject to either increasing shear stress or an osmotic gradient at a constant value of applied shear stress. However, direct deformability measurements are difficult to interpret when measuring heterogenous blood that is characterized by the presence of both rigid and deformable red cells. This is due to the inability of rigid cells to properly align in response to shear stress and results in a distorted diffraction pattern marked by an exaggerated decrease in apparent deformability. Measurement of the degree of distortion provides an indicator of the heterogeneity of the erythrocytes in blood. In sickle cell anemia, this is correlated with the percentage of rigid cells, which reflects the hemoglobin concentration and hemoglobin composition of the erythrocytes. In addition to measuring deformability, osmotic gradient ektacytometry provides information about the osmotic fragility and hydration status of erythrocytes. These parameters also reflect the hemoglobin composition of red blood cells from sickle cell patients. Ektacytometry measures deformability in populations of red cells and does not, therefore, provide information on the deformability or mechanical properties of individual erythrocytes. Regardless, the goal of the techniques described herein is to provide a convenient and reliable method for measuring the deformability and cellular heterogeneity of blood. These techniques may be useful for monitoring temporal changes, as well as disease progression and response to therapeutic intervention in several disorders. Sickle cell anemia is one well-characterized example. Other potential disorders where measurements of red cell deformability and/or heterogeneity are of interest include blood storage, diabetes, Plasmodium infection, iron deficiency, and the hemolytic anemias due to membrane defects.

Here we present techniques to measure red cell deformability and cellular heterogeneity by ektacytometry. These techniques are applicable to general investigations of red cell deformability and specific investigations of blood diseases characterized by the presence of both rigid and deformable red cells in circulation, such as sickle cell anemia.

Ektacytometry 血中红细胞异质性的测定

Decreased red cell deformability is characteristic of several disorders. In some cases, the extent of defective deformability can predict severity of ...