
- Description
- Additional Information
- Readable Documents
- Assay Principle
- Reviews
Key Benefits
- Safe – Non Radioactive Enzyme release assay.
- Versatile – Useful for measuring activity of T Cells, Primary Cells, NK, complement and other lytic agents.
- Assay can be run in serum supplemented media.
- Homogenous – One-step, no wash assay. Assay can be run in same plate as samples.
- FAST – Results in 3-5 minutes. Chromium 51 or europium release for measurement are time consuming. The inherent sensitivity of luciferase detection is enhanced by the amplification effect of enzyme turnover, which produces thousands, millions or billions of high – energy molecules for each molecule of the enzyme.
- Highly Sensitive – Can detect fewer than 500 cells/well in the presence of serum or as few as 10 cells/well in serum-free or heat-killed media.
- GAPDH: The fact that GAPDH is a natural component of cells, and does not need to be introduced into the cells in any manner, distinguishes this assay from all methods which require prelabelling of cells, transfection, transformation, or other methods of introducing proteins or other molecules into the target cells in order to generate a signal in a later step.
- Advantages for measurement of cell mediated or complement mediated cytolysis – It is usually desirable to use smaller numbers of TCells than are needed for the 51Cr – release assay, since excessive numbers of effector cells can increase the background signal. This is now possible due to the high sensitivity of aCella-Tox.
- ADCC / CMC Assays – A non radioactive alternative to 51Cr assays. Please click here for a direct comparison between the aCella-TOX and (51Cr) Chromium Release Methods
- HTS – Adaptable for High Throughput format
- Non-destructive assay allows monitoring of additional parameters.
Additional information
Kit Size | 500, 1000 |
---|---|
Includes | No Plates, 5 Lumi Plates, 5 Lumi Plates + 5 Tissue Culture Plates |
GAPDH is an important enzyme in the glycolysis and gluconeogenesis pathways. This homotetrameric enzyme catalyzes the oxidative phosphorylation of D-glyceraldehyde-3-phosphate to 1,3-diphosphoglycerate in the presence of cofactor and inorganic phosphate. In the aCella-TOX reaction scheme the release of GAPDH is coupled to the activity of the enzyme 3-Phosphoglyceric Phosphokinase (PGK) to produce ATP. ATP is detected via the luciferase, luciferin Bioluminescence methodology. Further, aCella-TOX is a homogeneous cytotoxicity assay; alternatively in dual mode, aCella-TOX can measure cytotoxicity and cell viability in the same plate. Culture supernatants can also be removed from the original plate and assayed in a different plate, allowing kinetics runs to be set up. The assay is non-destructive, allowing the monitoring of additional parameters such as gene expression.
Document Title |
aCella-TOX v1_3 Protocol |
aCella-TOX Datasheet |
msds.aCella-TOX |
Title | File | Link | Author(s) | Journal | Year; Edition:Pages |
Heat shock enhances the expression of cytotoxic granule proteins and augments the activities of tumor-associated antigen-specific cytotoxic T lymphocytes. | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3468674/ | Takahashi A, Torigoe T, Tamura Y, et al. | Cell Stress & Chaperones | 2012;17(6):757-763 | |
IGF-1R peptide vaccines/mimics inhibit the growth of BxPC3 and JIMT-1 cancer cells and exhibit synergistic antitumor effects with HER-1 and HER-2 peptides. | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4368154/ | Foy KC, Miller MJ, Overholser J, Donnelly SM, Nahta R, Kaumaya PT | Oncoimmunology | 2014;3(11):e956005 | |
HER-3 peptide vaccines/mimics: Combined therapy with IGF-1R, HER-2, and HER-1 peptides induces synergistic antitumor effects against breast and pancreatic cancer cells. | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4368151/ | Miller MJ, Foy KC, Overholser JP, Nahta R, Kaumaya PT | Oncoimmunology | 2014;3(11):e956012 | |
Phase I Active Immunotherapy With Combination of Two Chimeric, Human Epidermal Growth Factor Receptor 2, B-Cell Epitopes Fused to a Promiscuous T-Cell Epitope in Patients With Metastatic and/or Recurrent Solid Tumors. | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2773479/ | Kaumaya PTP, Foy KC, Garrett J, et al. | Journal of Clinical Oncology | 2009;27(31):5270-5277 | |
Identification of Cellular Proteins Required for Replication of Human Immunodeficiency Virus Type 1. | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3448097/ | Dziuba N, Ferguson MR, O"Brien WA, et al. | AIDS Research and Human Retroviruses | 2012;28(10):1329-1339 | |
Insulin-Like Growth Factor-1 Receptor Signaling Increases the Invasive Potential of Human Epidermal Growth Factor Receptor 2-Overexpressing Breast Cancer Cells via Src-Focal Adhesion Kinase and Forkhead Box Protein M1. | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4293451/ | Sanabria-Figueroa E, Donnelly SM, Foy KC, et al. | Pharmacology | 2015;87(2):150-161 | |
Combination Treatment with HER-2 and VEGF Peptide Mimics Induces Potent Anti-tumor and Anti-angiogenic Responses in Vitro and in Vivo. | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3075707/ | Foy KC, Liu Z, Phillips G, Miller M, Kaumaya PTP | The Journal of Biological Chemistry | 2011;286(15):13626-13637 | |
Resistance to Cytarabine Induces the Up-regulation of NKG2D Ligands and Enhances Natural Killer Cell Lysis of Leukemic Cells. | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2586691/ | Ogbomo H, Michaelis M, Klassert D, Doerr HW, Cinatl J. | Neoplasia (New York, NY) | 2008;10(12):1402-1410 | |
Anti-Tumor Effects of Peptide Therapeutic and Peptide Vaccine Antibody Co-targeting HER-1 and HER-2 in Esophageal Cancer (EC) and HER-1 and IGF-1R in Triple-Negative Breast Cancer (TNBC). | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4586465/ | Overholser J, Ambegaokar KH, Eze SM, et al. | Disis ML (Nora), ed. Vaccines | 2015;3(3):519-543 | |
Generation and preclinical characterization of an antibody specific for SEMA4D. | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4966508/ | Fisher TL, Reilly CA, Winter LA, et al. | mAbs | 2016;8(1):150-162 | |
A Human Anti-M2 Antibody Mediates Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC) and Cytokine Secretion by Resting and Cytokine-Preactivated Natural Killer (NK) Cells. | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4411161/ | Simhadri VR, Dimitrova M, Mariano JL, et al. | Reeves RK, ed. PLoS ONE | 2015;10(4):e0124677 | |
Natural Cytotoxicity Receptor-Dependent Natural Killer Cytolytic activity Directed at Hepatitis C Virus (HCV) Is Associated With Liver Inflammation, African American Race, IL28B Genotype, and Response to Pegylated Interferon/Ribavirin Therapy in Chronic HCV Infection. | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3997579/ | Meng Q, Rani MRS, Sugalski JM, et al. | The Journal of Infectious Diseases | 2014;209(10):1591-1601 | |
Myxoma Virus Infection Promotes NK Lysis of Malignant Gliomas In Vitro and In Vivo. | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3677932/ | Ogbomo H, Zemp FJ, Lun X, et al. | Ulasov I, ed. PLoS ONE | 2013;8(6):e66825 | |
Targeting a Glioblastoma Cancer Stem Cell Population Defined by EGF Receptor Variant III. | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5661963/ | Emlet DR, Gupta P, Holgado-Madruga M, et al. | Cancer research | 2014;74(4):1238-1249 | |
Genetically Associated CD16+56− Natural Killer Cell Interferon (IFN)-αR Expression Regulates Signaling and Is Implicated in IFN-α-Induced Hepatitis C Virus Decline. | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3295604/ | Conry SJ, Meng Q, Hardy G, et al. | The Journal of Infectious Diseases | 2012;205(7):1131-1141 |
Reference |
Methods and compositions for coupled luminescent assays. United States Patent 6,811,990 Corey and Kinders, issued November 2, 2004. |
Corey, M. J. and Kinders, R. J. (2005) "Coupled Luminescent Methods in Drug Discovery: 3-Min Assays for Cytotoxicity and Phosphatase Activity" Drug Discovery Handbook, Ed. Shayne Cox Gad, published by John Wiley & Sons, Inc., pp. 689-731 |
Corey, M.J., et al., "A Very Sensitive Coupled Luminescent Assay for Cytoxicity and Complement-Mediated Lysis," Journal of Immunological Methods 207:43-51, 1997. |
Corey, M. J., et al., Mechanistic Studies of the Effects of Anti-factor H Antibodies on Complement-mediated Lysis,” Journal of Biological Chemistry 275: 12917-12925, 2000. |
Schafer, H., et al., "A Highly Sensitive Cytotoxicity Assay Based on the Release of Reporter Enzymes, From Stably Transfected Cell Lines," Journal of Immunological Methods 204:89-98, 1997. |
Racher, LDH Assay, in Cell and tissue culture: Laboratory procedures in biotechnology, A. Doyle and J.B. Griffiths, Eds. 1998, John Wiley & Sons: Chichester, New York, Weinheim. p. 71-5 |
Decker, T. and Lohmann-Matthes, M.L. (1988) A quick and simple method for the quantitation of lactate dehydrogenase release in measurements of cellular cytotoxicity and tumor necrosis factor (TNF) activity. J. Immunol. Meth. 115, 61-9. |
Korzeniewski, C. and Callewaert, D.M. (1983) An enzyme-release assay for natural cytotoxicity. J. Immunol. Meth.64, 313-20. |
Crouch, S.P.M., et al., "The Use of ATP Bioluminescence as a Measure of Cell Proliferation and Cytotoxicity," Journal of Immunological Methods 160:81-88, 1993. |
Henry Ogbomo, Anke Hahn, Janina Geiler, Martin Michaelis, Hans Wilhelm Doerr, Jindrich Cinatl Jr. NK sensitivity of Neuroblastoma cells determined by a highly sensitive coupled luminescent method;Biochemical and Biophysical Research Comunications 339 (2006) pp375-379. Click here to read the publication |
Part# | Reagent | Temperature |
Part # 6001 | 4X Enzyme Assay Reagent | -20C |
Part # 3008 | 1X Enzyme Assay Diluent | 2-8C |
Part # 6003 | Glyeraldehyde 3-Phosphate (G3P) | -20C |
Part # 6002 | 50X Detection Reagent | -20C |
Part # 3009 | 5.5X Detection Assay Diluent | -20C |
Part # 3035 | Lytic Agent | 2-8C |
N/A | 5 Lumi Plates (Catalog# CLATOX100-3L) | N/A |
N/A | 5 Lumi Plates + 5 Tissue Culture Plates (Catalog# CLATOX100-3P) | N/A |
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尽量简洁
CRISPR derived RNA
就是用来抵御病毒侵袭/躲避哺乳动物免疫反应的基因系统衍生的RNA。
CRISPR----Clustered Regularly Interspaced
Short Palindromic Repeats
是在细菌和古细菌中广泛存在的成簇的、有规律的、间隔的短回文重复序列。07年,发现细菌可以用CRISPR系统抵抗噬菌体的入侵;08年,发现细菌的
CRISPR系统能够阻止外源质粒的转移。是细菌的一种获得性免疫系统。
Cas----CRISPR-associated
CRISPR/Cas9----CRIPSR-
Cas系统分为Type I、TypeII 、Type III三种类型。在TypeII
系统中包含一个标志性的Cas9蛋白(参与crRNA的成熟以及降解入侵的噬菌体DNA或外源质粒)。CRISPR/Cas系统和Cas9蛋白结合成复合
体,发挥识别和降解入侵的外源DNA功能。
2.CRISPR/Cas9的优缺点
优点:
构建方便简单快捷
高效的介导基因定点敲入和基因组的点突变
精确的切口酶活性提高了基因治疗的安全性
缺点:
严重的脱靶性
3.CRISPR/Cas9的用途
CRISPR/Cas9被改造成第三代人工核酸内切酶(前两代分别是ZFN和TALEN),用于复杂基因组的编辑,目前该技术应用于人类细胞、斑马鱼、小鼠及细菌的基因组精确修饰。
4.CRISPR/Cas9目前热点
CRISPR/Cas9有个极大的优势就是可以改造为切口酶,在DNA的特定位置制造单链切口,这样不会引起非同源末端连接,但是可以激活同源细胞的重组。
这套系统目前的主要用途是在以下几个方面:
基因定点InDel突变
基因定点敲入
两位点同时突变
小片段的缺失
编码基因和非编码基因(lncRNA、microRNA)的靶向基因敲除
一、CRISPR/Cas9系统的构成
CRISPR(clustered,regularly interspaced,short palindromic repeats)是一种来自细菌降解入侵的病毒DNA或其他外源DNA的免疫机制。在细菌及古细菌中,CRISPR系统共分成3类,其中Ⅰ类和Ⅲ类需要多种CRISPR相关蛋白(Cas蛋白)共同发挥作用,而Ⅱ类系统只需要一种Cas蛋白即可,这为其能够广泛应用提供了便利条件。目前,来自Streptococcus pyogenes的CRISPR/Cas9系统应用最为广泛。
Cas9蛋白(含有两个核酸酶结构域,可以分别切割DNA两条单链。Cas9首先与crRNA及tracrRNA结合成复合物,然后通过PAM序列结合并侵入DNA,形成RNA-DNA复合结构,进而对目的DNA双链进行切割,使DNA双链断裂。
研究人员为了将CRISPR/Cas9技术发展为高效的基因打靶工具,又进行了优化和改造。Cong, L.等人[1]在不影响系统效率的情况下,将crRNA和tracrRNA融合为一条RNA。通过这种简化,CRISPR/Cas9系统现仅包括两个元素:Cas9蛋白和sgRNA(single guide RNA)。因此现在人们将CRISPR/Cas9技术也称为Cas9/sgRNA技术。
二、CRISPR/Cas9技术的基因编辑机制
CRISPR/Cas9通过对预设的DNA位点进行切割,造成DNA双链断裂(DSB, double strand break)。这种DNA的损伤可以启动细胞内的修复机制,主要包括两种途径:
一是低保真性的非同源末端连接途径(NHEJ,Non-homologous end joining),此修复机制非常容易发生错误,导致修复后发生碱基的缺失或插入(Indel),从而造成移码突变,最终达到基因敲除的目的。NHEJ是细胞内主要的DNA断裂损伤修复机制。利用靶向核酸酶可以在受精卵水平高效的实现移码突变,从而制备基因敲除模式动物。CRISPR/Cas9技术的出现,使得无需再使用相应物种的ES细胞系就可以制备基因敲除模式生物,且已成功应用于小鼠[5]、大鼠[6]、猪[7]、灵长类[8]、果蝇[9]等等。
第二种DNA断裂修复途径为同源介导的修复(HR, homology-directedrepair),这种基于同源重组的修复机制保真性高,但是发生概率低。在提供外源修复模板的情况下,靶向核酸酶对DNA的切割可以将同源重组发生的概率提高约1000倍[10]。利用这种机制可以实现基因组的精确编辑,如:条件性基因敲除、基因敲进、基因替换、点突变等等。
CRISPR/Cas9技术以自己操作的便捷性,高效的基因编辑能力获得青睐,成为当下科研工作者的新宠儿。各大实验室纷纷加入开发CARISPR/Cas9技术的行列中,媒体也将之评为21世纪最有影响的十大技术之一。让我们跟随CRISPR/Cas9技术的脚步一起加强科研基础的建设,推动生物科研的进步!
详细信息你可以参考:http://www.bbctg.com.cn/show_2/1733.html
基因敲除指利用染色体间基因打靶的原理,通过将设计好的打靶载体导入细胞后,同源臂发生同源重组,从而在基因组的某个特定位点引入预定的突变,获得基因型发生了改变的动物。可以分为基因敲入和基因敲出:基因敲入即引入新的基因或突变;基因敲出即使某个特定的基因得到破坏,可以用于研究基因的功能。
科学家发现,细菌在遭遇噬菌体等病毒侵染之后,可以获得其部分DNA(脱氧核糖核酸)片段并整合进基因组形成记忆,当再次遭到入侵时,转录出相应的RNA(核糖核酸),利用其中的“定位信息”引导Cas蛋白复合物定位和切割、彻底地摧毁入侵病毒的DNA。CRISPR/Cas9技术就是利用这一原理,用一种定制的RNA引导Cas,对预设DNA位点进行切割,造成DNA断裂,启动细胞内基因组修复机制,实现基因敲除、特异突变的修复或引入和定点转基因等。
缺点:质粒仍然较大,转染难度相对较大。具有碱基识别偏好性,局限了基因编辑的运用范围,而且会导致不同基因位点编辑效率不同。筛选仍然需要较大工作量。
CRISPR 本身是一种防御系统,用以保护细菌和古细菌细胞不受病毒的侵害。在这些生物基因组中的 CRISPR 位点能表达与入侵病毒基因组序列相匹配的小分子 RNA。当微生物感染了这些病毒中的一种,CRISPR RNA 就能通过互补序列结合病毒基因组,并表达 CRISPR 相关酶,也就是 Cas,这些酶都是核酸酶,能切割病毒 DNA,阻止病毒完成其功能。
将 CRISPR/Cas 系统用于其它非细菌细胞需要满足两个条件:一个 Cas 酶,用于切断靶标 DNA,比如目的基因中的 DNA 片段,另外一个就是称为导向 RNA (gRNA)的 RNA 分子,这种分子能通过互补结合靶标。gRNA 也就是细菌细胞中 CRISPR RNA 的一个更短的版本,它能与 Cas 形成复合物,指导 Cas 到达正确的剪切位点。不过研究人员也可以通过结合其它元件,或者改变 Cas 活性,来调整这种工具在基因校正和基因调控方面的作用。
“目前,非传统基因编辑应用方面的生物学家利用一种新工具,分析细胞中,和整个生物机体中突变的作用”,来自加州大学伯克利分校的生物化学教授Jennifer Doudna 表示,她与她的同事解析了细菌细胞中 CRISPR 的作用机制。近期,Doudna 研究组利用这种工具,首次通过小鼠受精卵基因编辑构建了敲除小鼠。
不过 CRISPR 技术也存在一个主要的缺点,那就是缺乏特异性:一些 gRNA 分子结合的 DNA 只是部分与 gRN 互补。在这一方面,其它基因编辑方法,如锌指核酸酶(ZFN)和 TALENS 可能要比 Cas - gRNA 更为具有优势,因为这两者需要识别更长的靶标 DNA 序列。但是 ZFN 和 TALENS 方法在克隆和细胞表达方面要比 gRNA 难得多,而且研究人员通常还需要验证十几个不同的 TALENS,以及几十个不同的 ZFNs,来证明其中一个有效。
近期《科学家》(The Scientist)杂志汇总了基因编辑过程中 Cas 和 gRNA 的处理过程及解决方案,用于帮助新接触这一技术的研究人员熟悉这项热门技术。
如何 CRISPR 我的靶标?
由于 CRISPR 系统并不复杂,因此我们所要做的就是将带有质粒(能表达 Cas 和 gRNA)的细胞进行转染。研究人员可以采用一种 Cas 的变体,即 Cas9,这种酶来自于一种链球菌,由 RNA 进行指引,能无需其他蛋白的帮助而切割 DNA (Science, 337:816-21, 2012)。Cas9 既能切断与 gRNA 结合的 DNA 链,也能切断其互补链。目前可以从 Addgene 购买 Cas9 质粒(65 美元),将其直接转染入细胞。

