我还真得请你帮我分析分析,因为进展不顺。我这两天同时做了两种条件下的染色,一种是细胞种在coverslip上,然后加上反应混合物(lable+enzyme),用于显微镜观察;另一种是把细胞用Trypsin收集下来,然后加入反应混合物,用于做流式。其步骤包括固定(4%paraformaldehyde at RT for 1hr) 和permeablization(0.2%TritonX-100 on ice for 3 min) 然后加混合物 (50ul at 37C for 1hr in dark)基本上是一样的,但是奇怪的是,在coverslip上做出来的信号非常强,而把细胞收集下来的在显微镜底下几乎没有特异性的信号,这样子的肯定也做不了流式了。不知道是为什么? 作者: 了了 时间: 2012-1-20 10:34
我们实验室也有用thymidine双阻断的方法(2mM thymidine for 18hrs, then release for 8hrs, then 2mM thymidine again for 18hrs)来同步细胞,但是好象效率很低,一般同步到M phase的细胞只有30~40%左右,不知了了朋友的结果怎样?作者: 气泡 时间: 2012-1-20 10:51
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i-xviii Frontmatter and Index
Alice Longobardi Givan
Summary PDF Full Text (Size: 178K)
DOI 10.1002/0471223948.fmatter_indsub
Chapter 1:
1-9 The Past as Prologue
Alice Longobardi Givan
Summary PDF Full Text (Size: 198K)
DOI 10.1002/0471223948.ch1
Chapter 2:
11-14 Setting the Scene
Alice Longobardi Givan
Summary PDF Full Text (Size: 47K)
DOI 10.1002/0471223948.ch2
Chapter 3:
15-39 Instrumentation: Into the Black Box
Alice Longobardi Givan
Summary PDF Full Text (Size: 458K)
DOI 10.1002/0471223948.ch3 作者: zhezhe 时间: 2012-1-21 09:03
Chapter 4:
41-57 Information: Harnessing the Data
Alice Longobardi Givan
Summary PDF Full Text (Size: 451K)
DOI 10.1002/0471223948.ch4
Chapter 5:
59-80 Seeing the Light: Lasers, Fluorochromes, and Filters
Alice Longobardi Givan
Summary PDF Full Text (Size: 374K)
DOI 10.1002/0471223948.ch5
Chapter 6:
81-113 Cells from Without: Leukocytes, Surface Proteins, and the Strategy of Gating
Alice Longobardi Givan
Summary PDF Full Text (Size: 1115K)
DOI 10.1002/0471223948.ch6
Chapter 7:
115-122 Cells from Within: Intracellular Proteins
Alice Longobardi Givan
Summary PDF Full Text (Size: 168K)
DOI 10.1002/0471223948.ch7
Chapter 8:
123-158 Cells from Within: DNA in Life and Death
Alice Longobardi Givan
Summary PDF Full Text (Size: 709K)
DOI 10.1002/0471223948.ch8
Chapter 9:
159-174 The Sorting of Cells
Alice Longobardi Givan
Summary PDF Full Text (Size: 200K)
DOI 10.1002/0471223948.ch9 作者: zhezhe 时间: 2012-1-21 09:04
Chapter 10:
175-194 Disease and Diagnosis: The Clinical Laboratory
Alice Longobardi Givan
Summary PDF Full Text (Size: 427K)
DOI 10.1002/0471223948.ch10
Chapter 11:
195-223 Out of the Mainstream: Research Frontiers
Alice Longobardi Givan
Summary PDF Full Text (Size: 559K)
DOI 10.1002/0471223948.ch11
Chapter 12:
225-228 Flowing On: The Future
Alice Longobardi Givan
Summary PDF Full Text (Size: 56K)
DOI 10.1002/0471223948.ch12
229-233 General References
Alice Longobardi Givan
Summary PDF Full Text (Size: 62K)
DOI 10.1002/0471223948.biblio
235-256 Glossary
Alice Longobardi Givan
Summary PDF Full Text (Size: 131K)
DOI 10.1002/0471223948.gloss
257-261 Figure Credits
Alice Longobardi Givan
Summary PDF Full Text (Size: 107K)
DOI 10.1002/0471223948.credit 作者: 了了 时间: 2012-1-21 09:04
我买了EBioscience 的FITC-CD62P试剂,上面无实验步骤,说明也不清,只有Applications tested: This lot of AK-4 has been pre-titrated and tested by flow cytometric analysis of human peripheral blood leukocytes and can be used at 20ul per million cells(100ul blood).
试剂2瓶共2ml(100T), 它的意思是不是20ul FITC 用于100ul 全血.
若我只用5ul 血标本是否可按比例少用些试剂.作者: one 时间: 2012-1-21 09:24
有人在做流式时用过可以校正仪器,做标准曲线的微球吗?
(不用细胞表面抗原做对照)
============================================
This product can be purchased from BD Bioscience.作者: yychen 时间: 2012-1-21 10:34
1 x 106 PBS-washed cells from a single cell suspension are pelleted in a 12 X 75 mm culture tube. The pellet is resuspended in 0.875 ml of cold PBS and the suspension is mixed gently. Then, 0.125 ml of cold 2% formaldehyde solution is added and the mixture is immediately vortexed briefly. The suspension is incubated for at least 30 min or for up to 1 h at 4°C, centrifuged for 5 min at 250g, then the supernatant is removed.
Permeabilization
The pellet is gently resuspended in 1 ml of room temperature Tween 20 solution (0.2% in PBS) and the mixture is incubated for 15 min in a 37°C water bath. One ml of buffer is added and the suspension is spun for 5 min at 250g. The supernatant is removed and the internal staining then proceeds as described in the direct staining method for antibodies directly conjugated to a fluorochrome or in the indirect staining method for unlabelled antibodies.
Direct Staining Procedure
1. Resuspend cell pellet first in 50 microliters of HAB for approximately 1 min, then add 50 microliters of buffer and the appropriate amount of the fluorochrome-conjugated antibody.
2. Vortex briefly and incubate for 30 min at 4°C in the dark.
3. Wash twice with 1 ml of 0.2% Tween 20 solution by centrifugation at 250g for 5 min.
4. Resuspend samples in 1 ml of buffer and hold them at 4°C protected from light prior to analysis.
Indirect Staining Procedure
1-3. Process samples as above using a working dilution of unlabelled antibody.
4. Resuspend cell pellet first in 50 microliters of HAB for approximately 1 min, then add 50 microliters of a working dilution of the fluorochrome-conjugated second antibody.
5. Vortex briefly and incubate for 20 min at 4°C in the dark.
6. Wash twice with 1 ml of 0.2% Tween 20 solution by centrifugation at 250g for 5 min.
7. Resuspend samples in 1 ml of buffer and hold them at 4°C protected from light prior to analysis.
Note: do not use HAB for staining of immunoglobulin chains. Whenever available, use a monoclonal antibody and/or a reagent directly conjugated to a fluorochrome to minimize unspecific binding. Always use isotypic controls of the same heavy chain class at the same protein concentration as your relevant antibody for determination of background staining. For storage of samples longer than overnight and for biohazard considerations the samples can be resuspended in 1% formaldehyde solution after the internal staining procedure has been completed. 作者: 分子式 时间: 2012-1-21 10:43
Add 2 g paraformaldehyde powder (e.g., Sigma, St. Louis, MO) to 100 ml of 1 X PBS. Heat to 70°C (do not exceed this temperature) in a fume hood until the paraformaldehyde goes into solution (note that this happens quickly as soon as the suspension reaches 70°C). Allow the solution to cool to room temperature. Adjust to pH 7.4 using 0.1 M NaOH or 0.1 M HCl, if needed. Filter and store at 4°C protected from light.
Background information for intracellular staining by flow cytometry
For correlation of surface immunofluorescence with intracellular antigen expression the surface antigens are stained according to the "Monoclonal Antibody Staining Procedure" before fixation and permeabilization. However, please note that if a particular antigen is expressed on the cell surface as well as internally the surface antigens will also be detected by the antibody staining procedure after the fixation and permeabilization procedure. If you have stained surface antigens with mouse monoclonal antibodies, you either have to use a directly labelled antibody, an antibody made in a different species, or the avidin-biotin system for intracellular staining, because any anti-mouse second antibody that you are using for internal staining will also react with the mouse monoclonal antibody bound to surface proteins.
For correlation of intracellular antigen expression with DNA content please refer to the procedure "Staining Procedure for Correlation of Surface Antigen Expression Simultaneously with DNA content". Staining for internal antigens is done on fixed and permeabilized cells before staining for DNA content.
The fixation and permeabilization method described here employs a very mild treatment of cells with 0.25% buffered formaldehyde and Tween 20. Thus it offers a valuable alternative to alcohol fixation in cases where the immunoreactivity of the antigen is compromised by conformational changes due to excess crosslinking and harsh fixation conditions. In addition, it allows the preservation of cell surface immunofluorescence and the light scatter profiles of cell clusters for gating purposes in flow cytometry and gives very low coefficients of variation on DNA histogram distributions. It is therefore particularly suited for correlation of internal staining with surface antigen staining and DNA content.
The method described here was successfully used for internal staining of differentiation antigens, intracytoplasmic m , and vimentin in leukemic cell lines. In addition, the current method was able to permeabilize a variety of other cell types including human lymphocytes and thymocytes, and murine thymocytes and spleen cells for DNA staining. Thus it appears that the fixation and permeabilization procedure may be broadly applied to many different cell types as well as tissue culture lines. However, the current method may not be applicable to all cells and internal antigens. 作者: 分子式 时间: 2012-1-21 10:43
Whenever the results you are obtaining with this method are not satisfactory, please consider the following: the precise optimal conditions for staining of intracellular antigens may be influenced by the nature of the antigen and its localization. It might be necessary to modify the length of the incubation with the antibody and/or the temperature of the reaction. Keeping the antibody in the detergent solution during the incubation step has also been described as a measure to improve penetration of the reagent to the reaction site. In addition, it is also known that some cytoplasmic or nuclear antigens require a higher degree of fixation and/or a different fixative. Therefore, modification of the concentration of the fixative and/or the temperature of the fixation step can improve staining of some internal proteins.
For any quantitation of expression of intracellular proteins the results should be evaluated critically in each case to verify the specificity of the antibody-antigen reaction. The antibodies and their controls should be used at the same protein concentration. Antibodies from different manufacturers directed at the same antigen can display different properties when they are used for intracellular staining. All reagents should be titered for optimal internal staining and may require different amounts than those used for detection of surface antigens. The flow cytometric results should be verified by a comparison to results obtained with non-flow cytometric methods. Known negative cell controls should be fixed, permeabilized and stained to detect non-specific reactivity of the antibodies with fixed cells. The localization of the fluorescent reaction should always be verified by fluorescence microscopy.作者: lixi559 时间: 2012-1-21 10:46
请教了了老师:感谢您前几次的热心帮助,我目前测定的CXCR4的结果部分已经出来了,但表达不高,正常人仅12%的表达,而白血病的表达也只有20%,我查过相关的文献,有报道白血病最高时可表达到90%以上,不知道您在以前测定CXCR4的表达时是否也遇到过低表达的情况,什么原因?中国人白细胞CXCR4的正常表达有没有一个标准值?作者: toy 时间: 2012-1-21 11:25
请教了了兄以及各位热心的学哥学姐,我们实验室最近来了一台流式细胞仪,我想利用他做XY精子的分离试验,其中有一个关键的步骤,就是分离好的X或Y精子重新上机分析,通过数学模型曲线拟合法(curve-fitting math model to fit to a double-gaussian-peak curve)比较出分离后的X或Y精子的百分率(Welch GR and Johnson LA Sex preselection: laboratory validation of the sperm sex ratio of flow sorted X- and Y-sperm by sort reanalysis for DNA Theriogenology 1999;52:1343–1352)。请问这一拟和比较是如何操作的?是否需要专门的数量统计软件?
我是一只刚涉入流式的莱鸟,有很多问题请教。现在检测了白血病K562细胞株的细胞周期分析,发现结果不理想,表现为:在第二张散点图上细胞DNA积分由低到高几乎均匀呈斜线分布,不能反映明显的细胞周期。如果与正常对照相比,表现为异倍体细胞含量很多。对这样的情形不知道该如何分析?作者: toy 时间: 2012-1-21 12:59
我有看到一些介绍流式检测血小板活化的文献(如Preparation of Sample for studying platelet function by flow cytometry.Lori A.Krueger,Marc R.Barnard,A.L.Frelinger III,Mark I.Mark I.Furman,and Alan D.Michelson Center for platelet function studies,University of Massachusetts Medical School,Worcester,MA)有提到:Sodium citrate(a weak calcium chelator ) is the most commly used,EDTA(a stong calcium chelator)should be avoided because it causes dissociation of the integrinαⅡbβ3(GPⅡb-GPⅢa)complex,Heparin should also be avoided because it binds to,and may activate platelets.Non-chelating anticoagulants,e.g.PPACK(a direct thrombin inhibitor),may be preferable.作者: loli 时间: 2012-1-21 13:09 标题: 回复 #338 bamboo16 的帖子
1.我觉得前人的和自己的结果应该比较价值不大,因为每个人的样本收集及处理过程及采样条件不可能保证完全一样。主要是自己的不同实验组相互比较得出有用的结论。
2.流式要得到好的漂亮的正确结果,处理样本处理的要好,仪器条件的正确调节也很重要。
3.试剂说明上要求一小时内尽快做,应该是有其道理的,比如时间长了荧光会萃灭减弱,或者细胞本身的凋亡率会整加等,这些都会影响最终的结果。
4.另外,标准的染色步骤为(以BD的Annexin V : FITC Apoptosis Detection Kit II试剂盒为例 ):
Staining
1. Wash cells twice with cold PBS and then resuspend cells in 1X binding buffer at a concentration of 1 x 106 cells/ml.
2. Transfer 100 µl of the solution (1 x 105 cells) to a 5 ml culture tube.
3. Add 5 µl of Annexin V-FITC and 5 µl of PI.
4. Gently vortex the cells and incubate for 15 min at RT (25°C) in the dark.
5. Add 400 µl of 1X binding buffer to each tube. Analyze by flow cytometry within one hour.
其中商家提供的binding buffer中含有Ca+,它好像和annxin v与PS之间的结合有关,不知您是否使用相应溶液作为反应体系,它可能会影响最终结果。
Direct Linkage of OKT3 (or UCHT1; anti-CD3), 9.3 (anti-CD28) or Other Antibodies to Tosylactivated Dynal Beads
Reagents
FACS Staining Medium (FSM)
5% Fetal Calf Serum (Heat Inactivated) 50 ml
2 mM EDTA (0.5M solution) 4 ml
0.2% NaN3 (Sodium Azide) 2 ml
DPBS w/o CA and Mg q.s. to 1 L
Sterile Filter and store at 4oC
0.1M Borate Solution (Boric Acid, MW 61.83)
Boric Acid 0.618 g
Molecular Grade Water q.s. to 100 ml
Mix well and pH 9.5 with 10N NaOH
Sterile Filter and store at 4oC
Anti-CD28
Clone 9.3 ATCC (purified by Al Black)
Clone 28.6 eBiosciences Cat#16-0288-85, Lot# E000835
Procedure:
1. Take out 1 ml Tosylactivated Beads and wash in FSM 2X with magnet.
2. Dilute 300 ug of Antibody and q.s. to 1 ml of 0.1M Borate Solution, Add to 1 ml of beads in 15 ml conical tube
3. Parafilm wrap conical tube and place on rotator at 37oC O/N
4. Wash Beads 3X for 5 minutes at RT in FSM with magnet.
5. Final wash for 20 minutes at RT
6. Add 3 ml FSM per original volume of Beads and rotate O/N at 4oC
7. Resuspend in final volume of 10 ml FSM per original ml of Beads used
8. Bead concentration should be 40 x 106/ml作者: misswu61 时间: 2012-1-28 09:19
你这里的图形确实很糟糕。我可以提供些改善的建议:
1,如schoman兄所言,再建个横纵坐标分别为FL2-W/FL2-A目的是为了排除聚集体细胞;
2,70%酒精固定时轻轻加入缓慢晃动样本在4度固定一小时以上一般效果更好;同时固定后的细胞离心时转速要提高些大概400g,5min;
若使用的是自己配的试剂可以考虑一下RNase或PI方面的原因:
3,我看这种图形更像是RNase不起作用细胞内RNA未被消化的的结果,可以考虑一下你的RNase保存是否恰当?活性是否丧失?Treat cells with ribonuclease A (RNase A) (Sigma, Cat. No. R5500;100 Kunitz units/mg protein). The RNase A can be dissolved in DPBS at a concentration of 1 mg/ml, aliquoted, and stored frozen (–80°C). Add 50–100 µl of RNase A to each cell sample and incubate (30 min, 37°C).
4,Stain cells with 5–20 µg of PI (Sigma, Cat. No. P4170; Stock PI is at 1 mg/ml in distilled H2O) added to 1 ml of DPBS. Incubate for ≥ 30 min (room temperature) and then analyze samples by flow cytometry using linear amplification. Store samples protected from light at 4°C until flow cytometric analysis (ie, within 24 hours).
When analyzing, keep the flow rate under 400 events/second.
希望这些建议能改善你的实验结果
另外,可以使用ModiFIT软件分析你的实验结果阿作者: idea2011 时间: 2012-1-28 09:20
I think it is better to starve the cell for 24 hr to let the cell stop to grow.
The reason is that we want to know the effect of certain drug on the cell only. so before we test the cells. we let the cell at the same growing condition.(i.e. stop growing).作者: baidukk 时间: 2012-1-28 10:47
同型对照 又名isotype control
1. direct conjugate Ab. like mouse CD4-FITC, 它有一个subtype of IgG. eg. Ig1a
同型对照 is IgG1a-FITC only. 它只是IG并不认的抗原.
目的是把非特异性反应驱除.
因为每个抗体的subtype的 非特异性反应不一.作者: ladyhuahua 时间: 2012-1-28 10:48
同型对照 又名isotype control
1. direct conjugate Ab. like mouse CD4-FITC, 它有一个subtype of IgG. eg. Ig1a
同型对照 is IgG1a-FITC only. 它只是IG并不认的抗原.
目的是把非特异性反应驱除.
因为每个抗体的subtype的 非特异性反应不一.作者: zhezhe 时间: 2012-1-28 11:16
CD30, originally identified as a cell-surface antigen and clinical marker of Reed–Sternberg cells of Hodgkin's disease (HD), is also expressed at low levels on 3–31% of human peripheral blood T cells (mostly CD8+), as well as on resting murine B cells, macrophages, and natural killer (NK) cells (45–49). Activation or viral transformation increases CD30 expression on B and T cells, including γδ T cells (50, 51).
这段是从PNAS上摘录下来的,所以必须用CD3才能准确的区分出T细胞。不加抗体,流式细胞只能区分出淋巴细胞。免疫组化同样存在这样的问题。而ELISA测定的是可溶性CD30,意义完全不一样。
分离小鼠的单个核细胞我们常规都用的是人的淋巴细胞分离液,同样能得到较好的效果,如果你的效果不好,我觉得是实验操作的问题,可以向做的多的人多学习一下。专门适合小鼠的分离液不是没有,不过你的经费有限,我建议你不要买了。另外如果你分离单个核细胞的目的是用于流式检测,我觉得你可以省了这一步,因为用全血作流式时,流式可以区分开淋巴、单核、粒细胞。如果加入CD3抗体就可以区分出T细胞了。
每个标本都需要分离单个核细胞,如果做上100次,也会觉得很累,不如直接买个CD3的单抗标记T细胞,用全血标记,裂解红细胞后上机。
我建议你如下步骤:
1.取50ul小鼠外周全血,加入相应量的CD3单抗(建议用FITC标记)和CD30单抗(建议用PE标记,或者两者调换一下)。
2. 室温避光孵育30min。
3.加入红细胞裂解液裂解红细胞。
4.PBS洗涤细胞一次。
5. 上机检测。以FSC和SSC散点图,设门区分淋巴细胞。以CD3和CD30为横坐标轴和纵坐标轴,设立散点图,就可以分析CD30阳性的T细胞。作者: dotaaa 时间: 2012-1-28 13:09
1 Girolomoni G, Ricciardi?Castagnoli P. Dendritic cells hold promise for immunotherapy. Immunol Today, 1997;18:102-104
2 Zhang JK, Sun JL, Chen HB, Zhou YQ. Ultrastructural comparison of apoptosis of human hepatoma cells and LAK cells.
Shijie Huaren Xiaohua Zazhi, 1998;6:877-879
3 Winzler C, Rovere P, Rescigno M, Granucci F, Penna G, Adorini L, Zimmermann VS, Davoust J, Ricciardi Castagnoli P. Maturation
stages of mouse dendritic cells in growth factor-dependent long-term cultures. J Exp Med, 1997;185:317-328
4 Austyn JM. New insights into the mobilization and phagocytic activity of dendritic cells. J Exp Med, 1996;183:1287-1292
5 Zitvogel L, Regnault A, Lozier A, Wolfers J, Flament C, Tenza D, Ricciardi Castagnoli P, Paposo G, Amigorena S. Eradication
of established murine tumors using a novel cell-free vaccine: dendritic cell-derived exosomes. Nat Med, 1998;4:594-600
6 Wu ZJ, Gao QR, Lin CH, Chai ZK, Xu J, Ye XR. Lymphokine activated LAK/TIL cell and its phenotype. Zhonghua Weishengwuxue
Yu Mianyixue Zazhi, 1997;17:120-125
7 Wang J, Zhang JK, Chen HB, Xu JD. Morphologic observation of the effect of human peripheral blood dendritic cells on LAK cells
killing H-7402 Cells. Zhongguo Zuzhihuaxue Yu Xibaohuaxue Zazhi, 1996;5:72-76
8 Sashchenko LP, Lukyanova TI, Kabanova OD, Mirkina I, Yatskin ON, Pongor S, Gnuchev NV. Different pathways of the release
of cytotoxic proteins in LAK cells. Immunol Lett, 1996;53:25-29
9 Shresta S, Macivor DM, Heusel JW, Russell JH, Ley TJ. Natural killer and lymphokine-activated killer cells require granzyme B for
the rapid induction of apoptosis in susceptible target cells. Proc Natl Acad Sci USA, 1995;92:5679-5683
10 Shemtov MM, Cheng DL, Kong L, Shu WP, Sassaroli M, Droller MJ, Liu BC. LAK cell mediated apoptosis of human bladder cancer
cells involves a pH-dependent endonuclease system in the cancer cell: possible mechanism of BCG therapy. J Urol, 1995;154:269-274作者: 铜雀 时间: 2012-1-28 14:40
各种组织的消化方法类似,但是具体的消化时间是不同的,应该根据具体的条件加以优化。我建议你用胶原酶和胰酶联合消化。脂肪组织我的印象会漂浮在液面上,应该好去除。
由于你检测的是ER PR是位于细胞核内所以固定穿孔细胞是必须的。我最常采用的是多聚甲醛和皂素同时固定穿孔。70%的乙醇或80%的乙醇可以采用,可能其对蛋白的变性太强,所以有时影响抗原抗体的结合。所以用的少些。
具体的方法我建议你采用这篇文献的方法:
1: Breast Cancer Res Treat. 2003 Jul;80(1):1-13. Related Articles, Links
Quantitative fluorescence cytometric measurement of estrogen and progesterone receptors: correlation with the hormone binding assay.
Gritzapis AD, Baxevanis CN, Missitzis I, Katsanou ES, Alexis MN, Yotis J, Papamichail M.
Department of Immunology, Saint Savas Cancer Hospital, Athens, Greece. cacenter@otenet.gr
We describe, here, a rapid flow cytometry technique for the detection and quantification of estrogen (ER) and progesterone (PgR) receptors in several human cell lines and in clinical samples obtained from breast cancer tumors. ER and PgR quantitation can be very useful in patients with breast cancer as their role in diagnosis and prognosis is well established. However ligand binding assays and immunohistochemical assays are difficult to measure heterogeneity in individual cells. On the other hand, flow cytometry is a convenient tool for quantification in individual cells. Flow cytometric results with breast cancer cell lines and clinical samples were compared to those obtained by quantitative biochemical ER and PgR performed by the standard dextran-coated charcoal biochemical assay. The latter assay is affected by the level of endogenous steroids. This is also the case in the routine measurement of ER/PgR in patient's tumor cells whereby estradiol molecules in patient's serum produced negative or low values in the biochemical assay. The mAbs used in our flow cytometric method bind to their specific ER or PgR independently of whether they are preoccupied by their ligands and they produce reliable results. With the use of beads calibrated in MESF (Molecules of Equivalent Soluble Fluorochrome) units, the ER and PgR can be measured on a per cell basis. The flow cytometric method showed a strong correlation with biochemical receptor assessments of either ER alpha (ER alphaDCC, r = 0.918, p = 0.073) or PgR (PgRDCC, r = 0.75, p = 0.001). This study demonstrates that ER alpha and PgR can be detected by flow cytometry on a per cell basis in intact cells, and can be quantitated reliably in terms of MESF without the limitations of competition with serum's estradiol molecules作者: lixi559 时间: 2012-1-28 14:45
我想比较成纤维细胞和骨髓基质干细胞两者之间的ASMA表达量是不是一样多,或相差多少。
已经做了MSC的流式,结果如下:
Marker % Gated mean asma
------------------------------------------
All 100.00 33.66
positive 92.36 36.00
Marker % Gated mean control
-------------------------------------------
All 100.00 6.82
positive 4.32 72.82
文献中报道,可以采用Mean fluorescence intensity ratio(MFIR) Defined as mean fluorescence intensity of the studied antibodies divided by mean fluorescence intensity of corresponding isotype controls.
请问 ,根据我得结果,应该如何处理,得到MFIR,谢谢!!!作者: vvmmoy 时间: 2012-1-28 14:50
我想比较成纤维细胞和骨髓基质干细胞两者之间的ASMA表达量是不是一样多,或相差多少。
已经做了MSC的流式,结果如下:
Marker % Gated mean asma
------------------------------------------
All 100.00 33.66
positive 92.36 36.00
Marker % Gated mean control
-------------------------------------------
All 100.00 6.82
positive 4.32 72.82
文献中报道,可以采用Mean fluorescence intensity ratio(MFIR) Defined as mean fluorescence intensity of the studied antibodies divided by mean fluorescence intensity of corresponding isotype controls.
请问 ,根据我得结果,应该如何处理,得到MFIR,谢谢!!!
细胞内蛋白染色步骤:
请想做者可以参照本文:Cells from Within:
Intracellular Proteins
Although many applications of ¯ow cytometry involve the staining of
cells for proteins expressed on the outer membrane, cells also have
many proteins that are not displayed on their surface. With appropriate
procedures, ¯ow cytometry can provide a means to analyze
these intracellular proteins. The outer cell membrane is impermeable
to large molcules like antibodies; however, if we intentionally ®x cells
to stabilize proteins and then disrupt the outer membrane, the cells
can be stained with ¯uorochrome-conjugated monoclonal antibodies
against intracellular proteins. After time to allow the antibodies to
pass through the now-permeabilized membrane, the cells are washed
to remove loosely bound antibodies and then are run through the
¯ow cytometer to measure their ¯uorescence intensity.
This intensity should, under good conditions, be related to the
amount of the intracellular protein present. However, in describing
our ability to stain cells for surface proteins, we mentioned that it is
best to stain viable cells. Dead cells have leaky outer membranes;
they often show high nonspeci®c staining because antibodies get
through the disrupted membrane and become trapped in the intracellular
spaces. Therein lies a con¯ict in our ability to stain cells for
intracellular proteins. Because antibodies of all types are easily
trapped in the cytoplasm, there is greater potential for nonspeci®c
staining of permeabilized cells than intact cells. The very procedure
that we carry out to give access of the staining antibody to its target
(intracellular) antigen actually increases the access of all antibodies
to nonspeci®c targets. To lower this nonspeci®c background, antibody
titers are critical and washing steps are important. Unfortunately,作者: 园丁## 时间: 2012-1-28 14:53
115
Flow Cytometry: First Principles, Second Edition. Alice Longobardi Givan
Copyright 2001 by Wiley-Liss, Inc.
ISBNs 0-471-38224-8 (Paper); 0-471-22394-8 (Electronic)
even with low antibody concentrations and careful washing, background
¯uorescence from isotype-control antibodies is often considerably
higher on permeabilized than on intact cells.
There is, in addition, a second problem. The procedures used for
®xing and permeabilizing cellsÐto give the staining antibodies access
to intracellular proteinsÐcan modify or solubilize some antigens,
thus destroying the stainability of the very proteins that are being
assayed. To make matters worse, the protocol that works best for one
antigen may entirely destroy a di¨erent antigen. This should not be
surprising after consideration that ``intracellular'' includes proteins of
many types and in many di¨erent environments. Some intracellular
proteins are soluble, some are bound to organelle membranes, and
some are in the nucleus. Therefore, methods for staining cells for
intracellular proteins cannot be as standard or as dependable as the
methods for staining surface proteins. They have to be individually
optimized for the cells and the proteins in question.
METHODS FOR PERMEABILIZING CELLS
While not attempting to describe possible methods in detail, I feel it is
important here to point out the issues involved in intracellular staining
because they highlight some general issues that a¨ect all of ¯ow
cytometric analysis. Methods for permeabilizing and ®xing cells are
various and must be optimized for the particular intracellular antigens
being detected because some antigens are more robust than others in
the face of di¨erent agents. Figure 7.1 gives an example comparing
®xation/permeabilization e¨ects on two di¨erent intracellular antigens:
Five di¨erent ®xation/permeabilization protocols have been
used, and their e¨ects on staining PCNA (proliferating cell nuclear
antigen) and p105 (a mitosis-associated protein) have been compared.
The good news is that you can stain for intracellular antigens. The
bad news is that it may be di½cult to stain cells optimally for
two di¨erent antigens at the same time (and the relative intensity of
staining for two di¨erent antigens may tell you little about the actual
relative proportions of these proteins in the cell).
The general protocol for intracellular staining involves, ®rst,
staining the cells for any surface (outer membrane) antigens, as described
in the previous chapter. Then the surface proteins with their
Flow Cytometry 116
bound antibodies, as well as the intracellular proteins, are ®xed gently
to stabilize them. The purpose of the ®xation is to cross-link the
proteins well enough that they are not removed or washed out of the作者: 园丁## 时间: 2012-1-28 14:57
cells after the cells are permeabilized, but not so well that the intracellular
antibody binding sites are masked or destroyed. Although
ethanol and methanol can be used for ®xation (by themselves or
following another ®xative), the most common ®xative used prior to
intracellular staining is formaldehyde. Formaldehyde is generally
used at lower concentration and/or for a shorter period of time than
for routine ®xation of surface-stained cells (where ®xation overnight
in 1% formaldehyde is the [optional] last step of the procedure before
¯ow cytometric analysis). Formaldehyde (at 0.5±1.0%) for 10 min is
a good suggested concentration and time for cell ®xation, but lower
or higher concentrations, for shorter or longer periods of time, might
be required.
Fig. 7.1. The e¨ects of di¨erent ®xation protocols on the relative amounts detected
of two di¨erent intracellular proteins. Modi®ed from A McNally and KD Bauer as
published in Bauer and Jacobberger (1994).
Intracellular Proteins 117
This formaldehyde ®xation does permeabilize the cytoplasmic
membrane a bit (formaldehyde-®xed cells are permeable to small
molecules), but proteins are often cross-linked too tightly for staining
of intracellular proteins with antibodies. Therefore the ®xation step
is followed by a permeabilization step. Permeabilizing agents are
usually detergents, such as Triton X-100, digitonin, NP40, or saponin,
at concentrations of about 0.1%. Combined ®xation/permeabilization
reagents are also available as proprietary commercial reagents. With
luck, the detergent will open up the cell enough so that the now-®xed
proteins are accessible to the antibodies used for staining.
What are the criteria by which we can determine whether a ®xation/
permeabilization procedure has been optimized for an antigen in
question? This optimization is, in essence, no di¨erent from optimization
of a protocol for surface staining of cells. It is ®rst necessary
to maximize the ¯uorescence intensity of cells that are known to possess
the intracellular antigen (the positive control); ®xation time and
concentration need to be altered in combination with di¨erent detergent
concentrations to increase the positive staining. It is then necessary
to decrease the background staining (using cells stained with
isotype-control antibodies) as much as possible; this is done by trying
increasing detergent concentrations and washing the cells thoroughly
in bu¨er that contains the detergent. In other words, the goal is to
increase the signal-to-noise ratio. Because antibody concentration,
®xative agent, ®xative concentration, ®xation time, choice of permeabilization
agent, and concentration of that permeabilizing agent作者: 园丁## 时间: 2012-1-28 14:57
are all variables in this protocol (and the optimal characteristics of
each may be di¨erent for di¨erent antigens), staining for intracellular
antigens requires some persistence on the part of the investigator. The
following examples (in this chapter and in the following chapter on
DNA) will demonstrate, however, that it is certainly possible.
EXAMPLES OF INTRACELLULAR STAINING
From the point of view of a ¯ow cytometer, surface, cytoplasmic, and
nuclear proteins are similar. The ¯ow cytometer cannot ascertain the
location of the source of ¯uorescence. In addition, the nuclear membrane
has large enough pores that it provides little or no obstacle to
staining once the outer, cytoplasmic membrane has been breached.
Flow Cytometry 118
Cells have been stained successfully for nuclear proteins related to
proliferation (for example, PCNA, Ki-67, and various cyclins, which
will be discussed in the chapter on DNA) and to tumor suppression
(for example, p53, c-myc, and the retinoblastoma gene product).
They have also been stained for proteins bound to interior membrane
surfaces (e.g., Bcl-2, multidrug resistance protein [MDR], and P-glycoprotein),
and many strictly cytosolic proteins have been analyzed
(like tubulin, hemoglobin, surface proteins that exist intracellularly at
various stages of di¨erentiation, and many cytokines).
As an example of one of the more complex biological situations,
we can use the staining of cytokines as an illustration. Cytokines are
a diverse class of proteins that, in response to cell stimulation, are
synthesized and then secreted by leukocytes. For example, when T
lymphocytes are stimulated, either nonspeci®cally or by immunological
triggers, they begin to synthesize interferon-g in their endoplasmic
reticulum, send the proteins to the Golgi apparatus, and then
secrete the molecules into the environment for stimulation of neighboring
cells. To stain for intracellular interferon-g, the usual technique
is to stimulate cells with a biological trigger and then to incubate them
with an inhibitor (brefeldin A or monensin) for several hours. These
inhibitors block the normal secretion of proteins from the Golgi
apparatus and thus allow the cytokine concentration to build up in
the cell to levels that are detectable. After the incubation period, the
cells are stained for any surface antigens of interest, ®xed brie¯y in
formaldehyde, permeabilized with saponin, and, ®nally, stained with
a monoclonal antibody against interferon-g.
Figure 7.2 shows an example of the way in which cells can be
stained for a phenotypic surface marker (CD8) as well as the intracellular
cytokine, interferon-g. The ¯ow data indicate that interferong
is associated, after PMA-ionomycin stimulation, primarily with
CD8-negative cells. More of the CD8-negative than the CD8-positive
cells have intracellular interferon-g, and those that have that cytokine
have more of it per cell. The tricks in the procedure for staining intracellular
cytokines are as much biological as chemical (because the
stain is for the end result of a functional process). In addition to a
knowledge of how to ®x and permeabilize a cell and how to avoid
nonspeci®c staining, we require knowledge of how to trigger the作者: 园丁## 时间: 2012-1-28 14:57
cytokine production, knowledge of the time course of cytokine synthesis
after stimulation, and knowledge of how long cells can survive
Intracellular Proteins 119
Fig. 7.2. Dot plots showing the staining of lymphocytes for intracellular interferon-g
in conjunction with an outer membrane stain (against CD8) to phenotype the cytokine-
producing cells. Cells were stained for CD8 and then ®xed with formaldehyde
and permeabilized with saponin. The stimulus was PMA-ionomycin. Data courtesy
of Paul Wallace.
with brefeldin A or monensin inhibition so that they build up large
amounts of easily detectable cytokines but do not burst from this dire
treatment.
As another example of intracellular staining, we can look at data
from the staining of human breast tumor cells for cytokeratin and for
the estrogen receptor (both intracellular proteins). Tumor cells were
obtained following mastectomy by mincing and sieving the tissue to
form a single-cell suspension. The suspension was then treated with
saponin to permeabilize the cells. After staining for both cytokeratin
and the estrogen receptor, cytokeratin-positivity selects the cells in
the mixture that are of epithelial tumor origin (excluding stromal
or in®ltrating in¯ammatory cells). The two-color plot in Figure 7.3
indicates that the cytokeratin-positive (but not the cytokeratinnegative)
cells express the estrogen receptor strongly (estrogen receptor
positivity is associated with superior prognosis and a greater
responsiveness to endocrine therapy). Gating on the cytokeratinpositive
cells permits the analysis of tumor cells by themselves for the
estrogen receptor without concern about the variable contamination
of tumor cells by stromal cells in di¨erent samples.
Fig. 7.3. A dot plot (on the left) showing the staining of cells from a human breast
tumor for two intracellular proteins. Cytokeratin-positivity marks tumor cells in the
suspension, and estrogen receptor positivity on these cells indicates superior prognosis.
The plot on the right shows a correlation (in 27 breast tumors) between the
intensity of estrogen receptor staining by ¯ow cytometry and the level of estrogen
receptor binding (by radioligand binding assay). Modi®ed from Ian Brotherick et al.
(1995).
Intracellular Proteins 121
Having discussed the staining of cells for both extracellular and
intracellular proteins, and, in the process, learned something about
general ¯ow cytometric methodologies for analysis of data, we are
now ready, in the next chapter, to apply some of these general
methods to cellular components that are not proteins at all. 作者: 园丁## 时间: 2012-1-28 14:58
而文献上仅用乙醇固定30分钟后(作者用permeabilized with ethanol for 30 minutes and incubated with monoclonal antibody)就用一抗孵育。
请问各位前辈,
这有什么不同吗?或者那一个更好?最好后者可用,因为感觉简单。
谢谢!作者: milkdog 时间: 2012-1-28 15:02
而文献上仅用乙醇固定30分钟后(作者用permeabilized with ethanol for 30 minutes and incubated with monoclonal antibody)就用一抗孵育。
请问各位前辈,
这有什么不同吗?或者那一个更好?最好后者可用,因为感觉简单。作者: duoduo 时间: 2012-1-28 15:06
小弟从没有作过流式,实在是门外汉一个,最近想做流式,有几个菜鸟级问题向学长请教。我所参考的文献中老外用EDTA抗凝外周血,EDTA是不是枸橼酸钠?
文献中提到Leukocytes (5 × 105) obtained after erythrocyte lysis or MRC-5 fibroblasts were fixed and permeabilized by two technical procedures run in parallel. paraformaldehyde-Tween method和In the paraformaldehyde-methanol method 。是不是两种方法都可以,可以仍选其一?裂解红细胞以及给白细胞固定和通透,一般是用试剂盒好,还是自己配制试剂好?裂解红细胞后调整白细胞的密度时,一定要用培养基吗,老外没有说清楚用什么试剂调节白细胞的密度。
我已经将所参考的文献发到兄长的搜狐信箱了,请兄长帮我看看。
多谢。
1. check protein expression level, please use SDS-PAGE combine with weston blot. no need use flow cytometry
2. it is impossible to detect the proteins expressed in cytosolic by means of FCM if the no tag on the proteins(such as GFP or EGFP)作者: ha111 时间: 2012-1-28 17:46
小弟从没有作过流式,实在是门外汉一个,最近想做流式,有几个菜鸟级问题向学长请教。我所参考的文献中老外用EDTA抗凝外周血,EDTA是不是枸橼酸钠?
文献中提到Leukocytes (5 × 105) obtained after erythrocyte lysis or MRC-5 fibroblasts were fixed and permeabilized by two technical procedures run in parallel. paraformaldehyde-Tween method和In the paraformaldehyde-methanol method 。是不是两种方法都可以,可以仍选其一?裂解红细胞以及给白细胞固定和通透,一般是用试剂盒好,还是自己配制试剂好?裂解红细胞后调整白细胞的密度时,一定要用培养基吗,老外没有说清楚用什么试剂调节白细胞的密度。
我已经将所参考的文献发到兄长的搜狐信箱了,请兄长帮我看看。
多谢。
Tween可以穿孔白细胞吗作者: flower-201 时间: 2012-1-29 08:49
请教!
我使用annexin v 和 pi 双标测定法测定缺氧诱导视网膜色素上皮细胞的调亡。视网膜色素上皮来自ATCC,呈贴壁生长,37度胰酶消化2分钟,吹打后细胞极易呈团,很少能看见单个细胞。按照试剂盒(BD)的说明操作上机检测,每次死亡的细胞比例均超过20%,所以我的实验无法进行。恳请高手能指点如何准备细胞。万分感激!作者: 铜雀 时间: 2012-1-29 08:50
请教,不知那位老师能给帮助,我刚刚接触流式,什么尚不清楚。下载前面的文件确不能打开,郁闷ing。我想做一下几个指标:绝对细胞计数,细胞周期参数,蛋白多糖测定,细胞凋亡的检测。我养的是兔子椎间盘细胞,类软骨细胞,细胞外基质表达不高,PI染色是否可以检测前两个指标?蛋白多糖的检测以及凋亡的检测还请各位老师给予指导。谢谢作者: one 时间: 2012-1-29 09:33
Basic Protocol: Use of Indo-1 and Flow Cytometry to Measure Cellular Calcium Concentration
In this protocol, intracellular ionized calcium concentration ([Ca2+]i) is measured using indo-1 dye and ratiometric analysis. Most commercially available flow cytometers can be used to perform this assay, provided the instrument is capable of UV illumination; however, note that the Becton Dickinson FACScan and Coulter Profile and XL cannot be used. In addition, on many instruments, cells may be electronically sorted based on a particular calcium response; the sorted cells can be cultured for later analysis. The protocol can be divided into three stages: preparation of cells to be analyzed, setup of the flow cytometer, and data analysis and display (UNITS 10.3–10.6). The protocol requires expertise in basic flow cytometric techniques.
Materials
Murine splenic lymphocytes or human peripheral blood lymphocytes (UNIT 5.1)
Cell loading medium (see recipe)
100 mM probenecid (see recipe)
2 mg/ml indo-1 pentaacetoxymethyl ester (indo-1; see recipe)
1 mg/ml ionomycin (see recipe)
Dimethyl sulfoxide (DMSO; Sigma) or 10% (v/v) bleach in water
Saline (0.85% [(w/v)] NaCl) or PBS (APPENDIX 2A)
12 × 75–mm polypropylene tubes (Falcon)
Beckman TJ-6 rotor (or equivalent)
30° or 37°C water bath
Flow cytometer with UV light source and heated sample chamber (e.g., Becton Dickinson, Coulter, or Ortho), and software for kinetic and ratiometric analysis (Phoenix Flow Systems)
Load cells with indo-1
1. Collect lymphocytes in 12 × 75–mm polypropylene tubes and centrifuge 6 min at 180 × g (950 rpm in Beckman TJ-6), room temperature. Resuspend pellet in cell loading medium at 106 to 107 cells/ml.
Use murine splenic lymphocytes or human peripheral blood lymphocytes in initial experiments because they are easily and reliably loaded. Later, when the other aspects of the technique have been validated on the flow cytometer, both adherent and nonadherent cells can be analyzed.
Use polypropylene tubes to minimize loss of cells.
2. Optional: Add 100 mM probenecid (4 mM final).
Probenecid may improve cellular loading by minimizing leakage of indo-1 and cell-to-cell variation in dye content; sulfinpyrazone will also work (see Critical Parameters and Troubleshooting section on cellular response).
3. Add 2 mg/ml indo-1 to 2 µg/ml final. Incubate 30 min at 30° or 37°C.
The cells are loaded with the membrane-permeant form (pentaacetoxymethyl ester) of indo-1 (indo-1). Cellular esterases cleave the AM moiety, resulting in the trapping of the highly charged indo-1 in the cells. Typically, ~20% of the dye becomes trapped and concentrated within the cell.
Optimal conditions for loading must be empirically determined for each cell type. Rates of loading of indo-1 vary between cell types, especially as a consequence of variations in intracellular esterase activity. More rapid loading rates are seen in platelets and monocytes than in lymphocytes, and in growing cell lines rather than resting cells. More uniform loading is often observed if pluronic F-127 is included together with indo-1 (see Alternate Protocol 3). In addition, incubation at 30°C can aid loading of cells that tend to compartmentalize the dye.
An optional step is to stain an aliquot of indo-1-loaded cells for simultaneous immunofluorescence analysis (UNIT 6.2). This is done by treating the cells with saturating amounts of azide-free FITC- or phycoerythrin (PE)-conjugated antibody—as determined by titration experiments (UNIT 4.1) or by manufacturer's recommendations—and incubating 20 min at 22°C. Incubation may be done at 4°C to minimize antigen modulation, but after chilling, cells may require an extended equilibration time at 37°C to return to physiologic functioning for the calcium assay. In cases where antigen modulation is a problem, PE-conjugated antibodies are preferred, because unlike FITC, PE can still be detected after cellular internalization.
4. Centrifuge cells 6 min at 180 × g, room temperature. Gently resuspend (do not vortex) cells in cell loading medium at the desired cell concentration (~3 × 106 cells/ml). Store cells at room temperature and protect from light until analysis.
Leakage and compartmentalization of indo-1 is accelerated if cells are stored at 37°C.
It is often preferable to let cells rest for ~15 min before starting analysis. This presumably allows complete conversion of the calcium-insensitive form of indo-1 ester into the calcium-sensitive (charged) form of indo-1 and enhances cell uptake of additional equilibrating calcium to compensate for indo-1-bound calcium.
Set up the flow cytometer
5. Set up and adjust flow cytometer. Use a violet bandpass filter centered at 395 ± 10 nm and a blue bandpass filter centered at 500 ± 15 nm or a green bandpass filter centered at 525 ± 15 nm (see Critical Parameters and Troubleshooting).作者: 园丁## 时间: 2012-1-29 10:53
6. Set light scatter gates and optimize photomultiplier tube gain settings by placing the mean blue fluorescence in the upper half of the histogram channels and the violet fluorescence in the lower half of the histogram channels. Use linear rather than logarithmic amplification, and gate out dead cells with light scatter and violet fluorescence windows (see Critical Parameters and Troubleshooting).
For kinetic experiments such as this, the cytometer should be able to display time as a parameter. Violet and blue fluorescence can be plotted versus time; however, the violet/blue indo-1 ratio is optimally observed by allowing the cytometer to calculate this ratio, which can then be plotted as a function of time (see Anticipated Results and Figure 9.8.2).
Figure 9.8.2 Effects of T cell receptor stimulation on CD4 cell ionized calcium concentration ([Ca2+]i). Peripheral blood lymphocytes were loaded with indo-1 AM and stained with PE-anti-CD8. The cells were maintained at 37°C; after obtaining a baseline for ~1 min, anti-CD3 MAb was added during the gap in analysis. (A) The indo-1 ratio of 395 nm/500 nm fluorescence emission was calculated and the value for each cell displayed on the y axis versus time on the x axis. The results are displayed as a dot plot on a 100 × 100 pixel grid, where the number of cells per pixel is represented by increasing shades of gray. Changes in [Ca2+]i in the CD4 subset of T cells are depicted by setting electronic gates on the indo-1 fluorescence derived from the PE-negative cells. ( The mean response of the data from panel A plotted versus time.
[Full View]
7. Check instrument setup and cellular loading by treating ~1 × 105 cells (in cell loading medium) with 1 mg/ml ionomycin at 1 to 2 µg/ml final. An immediate response in 100% of cells should occur. Carefully remove any ionomycin that may adhere to the tubing by flushing the lines 1 min with DMSO or 10% bleach, then 1 min with cell loading medium.
It is critical that each experiment include a determination of R, the ratio of violet/blue fluorescence of resting cells, and Rmax, the ratio of violet/blue fluorescence of cells after stimulation by the calcium-ionophore ionomycin. If the instrument is properly aligned and the cells loaded adequately, the ratio of Rmax to R is 6:9 and >99% of the cells respond (see Critical Parameters and Troubleshooting). Use fluorescence microscopy to verify quality of indo-1 loading; compartmentalization of indo-1 is indicated by the presence of punctate dots of fluorescence.
8. To calibrate the indo-1 fluorescence ratio to the concentration of ionized calcium ([Ca2+]i), suspend cells in a series of calcium/EGTA buffers and ionomycin (see Support Protocol for details).
Analyze indo-1-loaded cells
9. Warm an aliquot of indo-1-loaded cells 5 to 10 min at 37°C before analysis. Use ~5 × 105 cells per 10-min assay.
10. Analyze cells at 37°C in cell loading medium. Use saline or PBS for the sheath fluid.
The rate of cell analysis can vary. Commonly, cells are analyzed at 200 to 300 cells/sec. A higher flow rate may be required when sorting cells or when analyzing a rare event, such as a calcium signal in a small subset of cells identified by monoclonal antibody staining (see Critical Parameters and Troubleshooting).
11. Optional (for instruments with dual-beam illumination): Set regions for simultaneous immunofluorescence analysis.
Combining the use of FITC and PE with indo-1 analysis allows determination of [Ca2+]i in complex immunophenotypic subsets. Limiting the analysis of indo-1 fluorescence to windows of FITC versus PE fluorescence allows information relating to each identifiable cellular subset to be derived from a single sample. On instruments without provision for analysis of four separate fluorescence wavelengths, both the FITC signal and the signal from calcium-free indo-1 can be detected with the same filter element. Note that the FITC signal must be delayed from the long-wavelength indo-1 signal derived from the UV laser.
12. If desired, sort cells on the basis of [Ca2+]i responses.
Sorting on the basis of indo-1 fluorescence can be an important tool for selection and identification of genetic variants in biochemical pathways leading to Ca2+ mobilization and cell growth and differentiation (see Background Information).
copied from CP.if any additional needs arise please let me know and i'll try my best作者: bohe221 时间: 2012-1-29 10:54
here is a basic protocol for determination of membrane antigenic protein,hope it do some good for you purpose.
Basic Protocol: Quantitative Determination of Cell Surface Antigens by Indirect Immunofluorescence Assay Using Qifikit Calibrator Beads
In this procedure, the cell specimen is labeled with a saturating concentration of either a primary mouse monoclonal antibody (MAb) directed against the antigen of interest or an irrelevant mouse monoclonal antibody (control). Saturation conditions are determined through titration experiments for each MAb investigated, using a fluorescein-conjugated anti-mouse secondary antibody. The primary antibody may be of any mouse IgG isotype. Under these conditions, the number of bound primary antibody molecules corresponds to the number of antigenic sites present on the cell surface.
Next, the cell specimen and the setup and calibration beads of the kit are labeled in parallel with a fluorescein-conjugated anti-mouse secondary antibody. The secondary antibody is also used at saturating concentrations. Consequently, fluorescence is correlated with the number of bound primary antibody molecules on the cells and/or the beads. Finally, thanks to the saturating conditions of both primary and secondary antibodies, the amount of fluorescence obtained directly correlates to the number of antigenic sites present on the cell surface. In other words, the cell specimen is analyzed on the flow cytometer and the ABC calculated by interpolation of the calibration curve.
Two types of beads are used in this protocol. Setup beads are a mixture of blank and high-level fluorescence beads. Autofluorescence of the beads may be different from that of the cells under analysis; therefore, it might be necessary to adjust the voltage of the fluorescence detector (PMT) to assure that both negative cells and the two populations of beads are displayed simultaneously on the fluorescence scale. Thus, the setup beads are used to establish the fluorescence windows of analysis of the flow cytometer.
Calibration beads are a mixture of different beads with well known numbers of antibody-binding sites per bead; fluorescence data corresponding to each of the five bead peaks are used for construction of the calibration curve of mean fluorescence intensity (MFI) against antibody-binding capacity (ABC).
Materials
Cell suspension: whole blood, cell lines, or isolated cells
Unconjugated primary antibody: mouse monoclonal IgG antibody specific for the cell surface antigen under evaluation
Unconjugated negative control antibody: irrelevant mouse monoclonal antibody of the same isotype as the unconjugated primary antibody
PBS/BSA/azide: PBS (APPENDIX 2A) with 0.5% (w/v) BSA and 0.1% (w/v) NaN3
QIFIKIT (Dako):
Setup beads
Calibration beads
F(ab¢ 2 fragment of FITC-conjugated goat anti-mouse (GAM) IgG 作者: 园丁## 时间: 2012-1-29 10:55
Computer with spreadsheet software (e.g., MS Excel)
TallyCAL software for Windows: dedicated software for automatic calculation of antigen density (optional)
Label cells with primary antibody
1. For each antigen to be tested, prepare two 12 × 75–mm test tubes labeled MAb Specificity and Isotype, respectively. Add 100 µl cell suspension to each tube.
If more than one cell surface antigen is to be determined using MAb of the same isotype and concentration, only a single isotype control tube will be necessary.
2. Add 10 µl unconjugated primary antibody to the sample in the MAb Specificity tube.
3. Add 10 µl unconjugated negative control antibody, adjusted to the same concentration as the primary antibody, to the sample in the Isotype (control) tube.
4. Incubate 30 to 60 min at 4°C.
Incubation time and temperature may depend upon the titration conditions used for staining with the specific monoclonal antibody reagent.
5. Add 3 ml PBS/BSA/azide to each tube. Vortex gently to mix.
6. Centrifuge 5 min at 300 × g, room temperature. Remove supernatant, leaving ~50 µl fluid in each tube.
7. Repeat steps 5 and 6.
Label QIFIKIT beads
8. Prepare two test tubes labeled Setup and Cal.
9. Add 100 µl of a homogeneous suspension of setup beads to the Setup tube.
Setup beads are a mixture of two different populations of beads: blank beads and beads with high numbers of monoclonal antibody molecules attached to each bead.
10. Add 100 µl of a homogeneous suspension of calibration beads to the Cal tube.
Calibration beads are a mixture of five different populations of beads, each population bearing different numbers of monoclonal antibody molecules. Lot-specific information for each population on the exact mean number of monoclonal antibody molecules attached per bead is included with each kit.
11. Add 3 ml PBS/BSA to each tube. Vortex gently to mix.
12. Centrifuge 5 min at 300 × g, room temperature. Remove supernatant, leaving ~50 µl fluid in each tube.
From this point on, the same procedure should be followed for both beads and cells.
Stain with secondary antibody to detect antibody binding
13. Dilute an appropriate volume of FITC-conjugated of F(ab¢ 2 fragment goat anti-mouse (GAM) IgG (secondary antibody) 1:50 in 1× PBS. Vortex gently to mix.
Each tube to be analyzed will require 100 µl secondary antibody.
14. To each tube, add 100 µl diluted FITC-conjugated secondary antibody. 作者: 园丁## 时间: 2012-1-29 10:55
15. Incubate 45 min at 4°C in the dark.
16. If the sample is whole blood, lyse erythrocytes by adding 1× ammonium chloride lysing solution to the tube. Incubate 10 min in the dark at room temperature.
Alternatively, reagents are commercially available for manual erythrocyte lysis. Follow instructions provided with the reagents.
17. Centrifuge 5 min at 300 × g, room temperature. Remove supernatant, leaving ~50 µl fluid in each tube.
If fixation is not required
18a. Add 3 ml PBS/BSA/azide to each tube. Vortex gently to mix.
19a. Centrifuge 5 min at 300 × g, room temperature.
20a. Remove supernatant, leaving ~50 µl fluid in each tube.
21a. Repeat steps 18a to 20a.
22a. Resuspend the pellet in 500 µl PBS/BSA/azide.
23a. Store tubes in the dark at 4°C no more than 2 hr before analyzing on a flow cytometer.
If fixation is required
18b. Add 3 ml PBS-azide to each tube. Vortex gently to mix.
19b. Centrifuge 5 min at 300 × g, room temperature. Remove supernatant, leaving ~50 µl fluid in each tube.
20b. Repeat steps 18b and 19b.
21b. Resuspend pellet in 500 µl of 1% paraformaldehyde in 1× PBS and incubate 2 hr at room temperature or overnight at 4°C. Add 3 ml PBS/azide to each tube and vortex gently to mix.
22b. Centrifuge 5 min at 300 × g, room temperature. Remove supernatant, leaving ~50 µl fluid in each tube. Resuspend the pellet in 500 µl PBS/azide.
23b. Store tubes up to 5 days in the dark at 4°C until analyzed on a flow cytometer.
It is recommended to check the stability of each of the studied parameters after storage.
Acquire flow cytometry data
24. Create an acquisition document containing one bivariate histogram of forward scatter (FS) versus side scatter (SS) in linear mode and one FITC fluorescence histogram in log mode.
25. Position FS and SS windows of analysis according to standard procedures, allowing a clear gating of the population of bead singlets.
26. Run the Setup tube and gate on the population of bead singlets on the FS/SS plot, collecting at least 10,000 total events or at least 5,000 gated events (Fig. 6.12.1A).
Figure 6.12.1 (A) Gate around the singlet population of setup beads. ( Corresponding FITC-associated histogram showing both lower- and higher-intensity populations simultaneously. (C) Gate around the singlet population of the calibration beads. (D) Corresponding FITC-associated fluorescence histogram showing the five bead populations. Note that histogram statistics, including geometric means, are displayed. (E) Gate around the cell population of interest. (F) Corresponding histogram plot of FITC-associated fluorescence. Histogram statistics are again displayed.
[Full View] 作者: 园丁## 时间: 2012-1-29 10:55
27. Use a histogram plot to show the FITC-associated fluorescence of the population of bead singlets gated from the FS versus SS dot plot (Fig. 6.12.1.
28. Adjust the voltage of the FITC fluorescence detector to assure that both negative cells and the higher- and lower-intensity populations of setup beads are all displayed simultaneously on the FITC-associated histogram (Fig. 6.12.1. Keep instrument settings constant for subsequent measurements of calibrator beads and cells.
29. Run the Cal tube and gate on the population of bead singlets on the FS/SS plot, collecting at least 10,000 total events or at least 5,000 gated events (Fig. 6.12.1C).
30. Analyze FITC-associated fluorescence for the population of singlet beads using a histogram plot. Adjust markers around the five bead peaks (Fig. 6.12.1D). Show histogram statistics, making sure that geometric means are displayed.
31. Analyze MAb Specificity and Isotype tubes containing the cells. For cell acquisition, adjust FS and SS windows to clearly display the cells of interest (Fig. 6.12.1E).
32. Analyze the FITC fluorescence for the cell population of interest using a histogram plot. Adjust markers around the positive and/or the negative cell population peaks (Fig. 6.12.1F). Show histogram statistics, making sure that geometric means are displayed.
Construct the calibration curve
33. View the histogram statistics of the Cal tube.
Either MFI arbitrary units or channel numbers are useful.
34. On a computer with spreadsheet software, enter either the MFI or the channel numbers as the dependent variable y.
35. Enter the lot-specific values for the ABC molecules for each of the five bead peaks as the independent variable x.
36. If MFI is used, calculate log10 for the FITC-associated MFI values and log10 for the ABC levels per bead.
37. Calculate and plot the linear regression line of log10 ABC per bead against log10 MFI or against channel numbers, using the equation y = mx + c, where y equals log10 MFI or channel numbers and x equals log10 ABC per bead.
Calculate the ABC of the cell population under analysis
38. To determine an unknown ABC for a given cell population, introduce the log10 FITC MFI or channel number obtained for those specific cells as y in the linear regression equation and derive the log ABC value. Calculate the anti-log of the value obtained to get the ABC value. 作者: 园丁## 时间: 2012-1-29 10:56
39. Optional. If necessary, correct the ABC of the cell population under analysis for the ABC obtained with the isotype control on the blank bead tube by subtracting the ABC of the Isotype from that of the MAb Specificity tube.
The ABC of the Isotype is generally negligible, but in case of low antigen densities it might be significant and therefore should be subtracted from the ABC value obtained for the MAb Specificity tube.
ABC values rather than raw values are subtracted because log-transformed data cannot be subtracted directly.作者: utt0989 时间: 2012-1-29 10:56
Reagents
Cold absolute ethanol.
0.5 M Na citrate stock (filtered), 50mM diluted stock.
10 mg/ml RNase A (Boil 10 mins, cool, filter and store at -20°C).
4 mg/ml Propidium iodide (PI) (filter and store in dark at -20°C).
Protocol
Spin down 107 cells from an exponentially growing culture - 2000 rpm for 5 mins. Pour off supernatant.
Vortex tube while adding 1.0 ml cold 70% EtOH.
Store at 4 °C (cells keep ~indefinitely).
When you want to process the cells, take 0.3 ml (this will be 2-3 x 106 cells, assuming a little loss in the washing) and add to 3 ml 50 mM Na citrate in a 5ml Falcon tube. Mix and spin 2000 rpm for 5 mins.
Discard supernatant and resuspend pellet in 0.5 ml 50mM Na citrate containing 0.1 mg/ml RNase A. Leave in 5 ml Falcon tube and put in 37 °C room for 2 h.
For staining:
Propidium Iodide
Add 0.5 ml 50 mM Na citrate containing 8 µg/ml PI, so that final concentration in the sample is 4 µg/ml. There can be non-specific staining of yeast (pombe) ends at higher concentrations if cells are starved, or spores. Cells can be processed immediately or conveniently stored overnight at 4°C in the dark before processing the next day. If necessary cells can be stored at this stage for a maximum of a week (4°C in the dark). Check them under the fluoresence microscope (red channel) to verify staining.
(Optional) Just before processing the cells, sonicate for 45 s again leaving cells in the 5 ml Falcon tubes. Sonication prevents doublets of cells which give spurious peaks and is particularly useful if your cells have varying DNA contents and will clean up spores or wee mutants.
Approximate settings on the FACScan for Propidium Iodide
Detector FSC E00 Gain:3
Detector FL2-A Voltage:890 Gain:2
不知你英文怎么样?我可以给你提供一本我的收藏:《Flow Cytometry First Principles Second Edition》。文件比较大,无法用附件的形式上传,想要的话可以和我PM联系,或留下你的E-mail。希望这本书对你有所帮助!其他想要的朋友也可以向我索取资料。作者: ending 时间: 2012-1-29 12:40
是BD的protocol要求的。Resuspend cells in cold wash buffer (PBS with 0.1% NaN3 and 1.0% fetal bovine serum, pH 7.2 - 7.4) at a concentration of 2 × 107 cells/ml. Aliquot
0.05 ml of cell suspension (106 cells) into tubes or microwell plates for staining.
在处理标本时常取100,000-1,000,000个细胞/test。试剂厂家提供的滴度也常以此为样本的基础,然后所加的抗体应该都是过饱和的(常为1ug/test左右),这样你所要得到的细胞抗原的含量才不会受所加细胞多少或抗体多少的少许变化的影响。所以我认为10E5,10E6都可以,这不是问题的关键。作者: newway 时间: 2012-1-29 13:08
(一)白血病的分类研究
B-cell ALL
1.TdT positive.
2.CD10 positive, except for progenitor B-cell ALL.
3.HLA-DR positive.
4.CD19 frequently present without CD20.
5.Positive cytoplasmic μ chain in pre-B-cell type only.
6.Monoclonal surface immunoglobulin in L3 only.
7.Immunoglobulin gene or T-cell receptor gene rearrangement.
T-cell ALL
1.Positive TdT.
2.Usually negative CD10 and HLA-DR (more frequently positive in adult T-ALL).
3.CD7 is frequently the only positive T-cell marker, but all T-cell markers can be present.
4.T-cell receptor gene rearrangement.
Acute Myeloblastic Leukemia without Maturation (M1)
1.Greater than 90% of myeloblasts in the bone marrow.
2.Greater than 3% MPO-positive blasts in the bone marrow.
3.Blasts positive for CAE.
4.Blasts positive for CD33/CD13, HLA-DR.
5.Blasts negative for CD14, CD15,CD41/CD61,glycophorin.
6.Immunoglobulin and/or TCR gene arranged in mixed-lineage leukemia.
7.Specific cytogenetic abnormalities: t(9;22)(q34;q11) and inv(3) (q21;q26).作者: 黄花菜 时间: 2012-1-29 14:37
Acute Myeloblastic Leukemia with Maturation (M2)
1.30-90% of myeloblasts present in bone marrow.
2.Less than 20% monocytic precursors in the bone marrow
3.Less than 5×10 9 /L monocytic precursors in the peripheral blood.
4.Cytochemical stain for blasts: Positive for myelo-peroxidase and chloroacetate esterase but negative for α-naphthyl butyrate esterase.
5.Monoclonal antibody panelositive for CD13,CD15,CD33,HLA-DR,but negative for CD14.
6.Specific cytogenetic abnormality: t(8;21)(q22;q22).
Acute Promyelocytic Leukemia (M3)
1.Presence of more than 30% hypergranular (or hypogranular) promyelocytes in the bone marrow.
2.Presence of multiple Auer rods in the cytoplasm of leukemia.
3.Cytochemical staining: Strongly positive for myeloperoxidase and chloroacetate esterase, but negative for a-naphthyl butyrate esterase.
4.Immunophenotypeing : Positive for myelomonocytic antigens (CD13,CD15,CD33),negative for monocytic antigen (CD14) and HLA-DR.
5.Abnormal karyotype : t(15;17) detected by cytogenetic or molecular biological techniques.
6.Coagulation work up: Decreased platelets and fibrinogen; prolonged prothrombin, activated partial thromboplastin and thrombin times, and increased levels of fibrin degradation products.
Acut Myelomonocytic Leukemia(M4)
1.Presence of at least 30% myeloblast-monboblasts in bone marrow.
2.Monocytic component : More than 20% but less than 80% in bone marrow.
3.If monocytic component is less than 20% in the bone marrow.
A.Monocyte count in peripheral blood should be greater than 5×10 9 /L.
B.Serum lysozyme concentration should exceed three times the normal value.
4.Myeloblasts :More than 20% in bone marrow.Acute Myeloblastic Leukemia with Maturation (M2)
1.30-90% of myeloblasts present in bone marrow.
2.Less than 20% monocytic precursors in the bone marrow
3.Less than 5×10 9 /L monocytic precursors in the peripheral blood.
4.Cytochemical stain for blasts: Positive for myelo-peroxidase and chloroacetate esterase but negative for α-naphthyl butyrate esterase.
5.Monoclonal antibody panelositive for CD13,CD15,CD33,HLA-DR,but negative for CD14.
6.Specific cytogenetic abnormality: t(8;21)(q22;q22).
Acute Promyelocytic Leukemia (M3)
1.Presence of more than 30% hypergranular (or hypogranular) promyelocytes in the bone marrow.
2.Presence of multiple Auer rods in the cytoplasm of leukemia.
3.Cytochemical staining: Strongly positive for myeloperoxidase and chloroacetate esterase, but negative for a-naphthyl butyrate esterase.
4.Immunophenotypeing : Positive for myelomonocytic antigens (CD13,CD15,CD33),negative for monocytic antigen (CD14) and HLA-DR.
5.Abnormal karyotype : t(15;17) detected by cytogenetic or molecular biological techniques.
6.Coagulation work up: Decreased platelets and fibrinogen; prolonged prothrombin, activated partial thromboplastin and thrombin times, and increased levels of fibrin degradation products.
Acut Myelomonocytic Leukemia(M4)
1.Presence of at least 30% myeloblast-monboblasts in bone marrow.
2.Monocytic component : More than 20% but less than 80% in bone marrow.
3.If monocytic component is less than 20% in the bone marrow.
A.Monocyte count in peripheral blood should be greater than 5×10 9 /L.
B.Serum lysozyme concentration should exceed three times the normal value.
4.Myeloblasts :More than 20% in bone marrow.
5.Myeloperoxidase positive cells : More than 3%.
6.Chloroacetate esterase and a-naphthyl butyrate esterase-positive cells: Roughly more than 20% each.
7.Abnormal chromosome 16 in M4 : Associated with M4 EO subtype.
8.Immunophenotype : Positive for CD13,CD14,CD15,CD33,and HLA-DR ,negative for CD41/CD42/CD61 and glycophorin A.
Acute Monoblastic Leukemia (M5)
1.Presence of more than 80% monocytic component among the nonerythroid cells in the bone marrow.
A.M5a: 80% or more of monocytic components are monoblasts.
B.M5b: Predominantly monocytes and promonocytes.
2.Elevation of serum and urine lysozyme levels.
5.Myeloperoxidase positive cells : More than 3%.
6.Chloroacetate esterase and a-naphthyl butyrate esterase-positive cells: Roughly more than 20% each.
7.Abnormal chromosome 16 in M4 : Associated with M4 EO subtype.
8.Immunophenotype : Positive for CD13,CD14,CD15,CD33,and HLA-DR ,negative for CD41/CD42/CD61 and glycophorin A.
Acute Monoblastic Leukemia (M5)
1.Presence of more than 80% monocytic component among the nonerythroid cells in the bone marrow.
A.M5a: 80% or more of monocytic components are monoblasts.
B.M5b: Predominantly monocytes and promonocytes.
2.Elevation of serum and urine lysozyme levels.作者: 黄花菜 时间: 2012-1-29 14:38
3.Cytochemistry:
Myeloperoxidase : may or may not be positive.
Nonspercific esterase : strongly positive .
Specific esterase and periodic acid-Schiff: usually negative .
4. Immunophenotype : Positive for CD11c,CD13,CD14,CD15,CD33,HLA-DR,negative for CD41, CD42, CD61 and glycophorin.
5. Cytogenetics : Association with t/del(11)(q23).
Acute Megakaryoblastic Leukemia (M6)
1.Presence of at least 50% erythroblasts among all nucleated cells in the bone marrow.
2.Presence of at least 30% myeloblasts among all nonerythroid cells in the bone marrow.
3.PAS positivity in all mature and immature nucleated erythroid cells.
4.Glycophorin-A antibody or other erythroid antibodies: The only reliable antibody for phenotyping.
5.React variably to myelomonocytic (CD13,CD33) and platelet (CD41) antibodies.
6.Most frequent cytogenetic abnormalities: -5/5q- ,-7/7q- .
Acute Megakaryoblastic Leukemia (M7)
1.Presence of 30% or more megakaryoblasts in the bone marrow.
2.Excess of blasts with increased numbers of maturing megakaryocytes in bone marrow biopsy , plus identification of megakaryoblasts in the peripheral blood and bone marrow aspirate by immunologic techniques.
3.Electron microscopic identification of platelet peroxidase in leukemic cells.
4.Monoclonal antibodies : CD41,CD42,and CD61 are specific for megakaryoblastic.
5.Myelomonocytic markers : Positive for CD33 but negative for CD13,CD14 and CD15.
6.PAS Staining pattern in megakaryocyte-megakaryoblasts : Periphery of cytoplasm and concentrated on cytoplasmic blebs.
7.t(1;22)(p13;q13): Specific for M7 infants.
有哪位使用过BD的Annexin V PE/7-AAD凋亡检测试剂盒的,我做全血标本中淋巴细胞的凋亡检测。
技术支持告诉我先溶血(不含固定成分的溶血素是ebioscience的),完了洗后加抗体。我检测的是CD3+/CD8+细胞群的凋亡。
现在的情况是:单加Annexin V PE的管没有阳性细胞群,单加7-AAD的有明显阳性细胞群,而加了CD8FITC/Annexin V PE/7-AAD/CD3APC的管在两种条件下是两种情况:
1.FL2-FL1的补偿为0时,Annexin V PE/7-AAD点图出现四群细胞,横平竖直,非常漂亮,此时CD8FITC/Annexin V PE点图上双阳性群呈45度斜线。
2.FL2-FL1的补偿为21%时,Annexin V PE/7-AAD点图只有两群细胞,无Annexin V PE阳性细胞。此时CD8FITC/Annexin V PE点图上只有CD8FITC+/Annexin V PE-群。
问题:
1.操作步骤对不对?
2.FL2-FL1的补偿对Annexin V PE/7-AAD点图的影响怎么会如此大?
3.应该怎么做才有正确的数据?
另:我的全血在Annexin V PE/7-AAD点图上应出现四群细胞。作者: gogo 时间: 2012-1-29 15:29
请教各位高手:
下图1是检测肿瘤中乏氧细胞内的pimonidazole抗体浓度得到的直方图,作者并没有做阴性对照,而是采用其所谓的“最小二乘法(least-squares approach)”得到第2张图中的三个高斯分布图,分别代表有氧、中度乏氧和乏氧的3群细胞(随着乏氧程度加重,抗体浓度越高)。
原文的描述是这样:Univariate histograms, plotted as cell number versus logarithm of fluorescent antipimonidazole antibody intensity, were analysed by a least-squares approach for 3 Gaussian distributions representing aerobic, intermediate, and hypoxic tumour cell populations. No constraints on the positions of the distribution meanswere imposed. Therefore, the range but not absolute fluorescence intensity determined whether a hypoxic fraction could be reliably identified within cells from different tumours.
我同我们实验室的老师商量过,他也不知道。
大侠们该出手时就出手吧,帮小弟想一下,如何实现这一步。
请问一个问题
文章意见修回,有一条是关于流式细胞技术的
The second apoptosis assay is even more problematic in its presented form. First the figure needs the explanation what is measured (AnnexinV-FITC x-axes; PI y-axes?). Second, constant cell numbers should be shown for all dot blots. Third, the controls already have too many PI positive cells (maybe due to a too long exposition of the cells to trypsin?). Fourth, the percentage data in the lower right quadrant can't be correct, especially in the important samples with drug combinations.
这段话当中的constant cell numbers should be shown for all dot blots.是什么意思啊作者: wsll 时间: 2012-1-30 16:29
弱智问题1:要有多少经验才能自如用SSC VS FSC 来区分白细胞中的淋巴亚群?我经常分不开中性粒和单核,也经常分不开淋巴和碎片。再怎么加大FSC的电压,图形中还是那样。
问题2:我最近做的淋巴亚群中,应该是一群淋巴的那个位置,出现了两群分离的细胞,它们都是淋巴细胞吗?为什么会分离?怎样做才能让它们合起来呢?
小弟刚开始做流式不久,而且也都是在做分选,对于流式分析的图谱理解的不多,现在有这样一张图,是从paper里看到的,有几个问题
1.图上各种颜色是什么意思呢?尤其是红色区域,为什么会出现在中间?
2.关于这张图,paper里有这么一句 Lhx6-GFP+cells were isolated by FACS,and the GFP+ cells, which were ~2% of the total viable cells,想请教一下,从图上如何看出是2%呢?
问题比较弱弱,希望好心战友能给解答一下,谢谢
弱智问题1:要有多少经验才能自如用SSC VS FSC 来区分白细胞中的淋巴亚群?我经常分不开中性粒和单核,也经常分不开淋巴和碎片。再怎么加大FSC的电压,图形中还是那样。
问题2:我最近做的淋巴亚群中,应该是一群淋巴的那个位置,出现了两群分离的细胞,它们都是淋巴细胞吗?为什么会分离?怎样做才能让它们合起来呢?