流式细胞术定量检测细胞凋亡3种方法的比较研究

目的：探讨流式细胞术定量检测细胞凋亡３种方法的价值。方法：同时使用ＰＩ染色，ＴＵＮＥＬ及Ａｎｎｅｘｉｎ Ｖ／ＰＩ３壹量检测地塞米松处理小鼠的胸腺细胞凋亡发生率。结果：ＰＩ染色，Ａｎｎｅｘｉｎ Ｖ／ＰＩ，ＴＵＮＥＬ３种方法凋亡检出率分别为２７．１９％，３２．２８％，５０．１７％，两者之间均有显著差异。     

A rapid method for measuring apoptosis and dual-color immunofluorescence by single laser flow cytometry

A sensitive method for quantification of cells undergoing apoptisis that permits the simultaneous measurement of dual-color cell surface immunofluorescence is presented. Unfixed cells are stained with 7-amino-actinomycin D (7-AAD) for discrimination of live from early apoptotic cells and from cells which have lost membrane integrity (late apoptotic or necrotic, dead cells). Owing to its spectral characteristics 7-AAD can be combined with fluorescein-isothiocyanate (FITC) and phycoerythrin (PE) cell surface staining. After staining, the samples can be treated with paraformaldehyde (PF) solution to eliminate the risk for exposure of laboratory personnel to biohazardous agents and to preserve the cells through fixation for later analysis on the flow cytometer. The value of the method is shown on the measurement of apoptosis in human thymocytes and in human peripheral blood mononuclear cells (PBMC) exposed to various inducers of active cell death. The method is validated by fluorescent activated cell sorting in combination with morphologic examination of the sorted cells. The technique we are presenting is particularly valuable in a clinical setting because it allows rapid multiparameter analysis of apoptosis in combination with cell surface phenotype on biohazardous samples with single laser instrumentation.     

A flow cytometric method for the detection of intracellular basic proteins in unseparated peripheral blood and bone marrow eosinophils

Eosinophils and their basic proteins play a major role in allergic disease and methods are required to monitor their expression in clinical situations. In this article we describe a flow cytometric method for the detection of intracellular eosinophil cationic protein (ECP) and eosinophil peroxidase (EPO) in unseparated clinical samples. After fixation with parabenzoquinone and permeabilization with n-octyl-β- -glucopyranoside, the detection of intracellularly stored proteins was achieved using of monoclonal antibodies against ECP (EG1, EG2) and EPO in combination with an FITC-labeled second step antibody. Confocal microscopy was used to demonstrate the intracellular origin of the fluorescent signal. Fixation with parabenzoquinone was superior to a previously described protocol using paraformaldehyde, since it reduces non-specific binding of FITC to the basic proteins in eosinophils. Fixation and permeabilization do not alter the light scatter characteristics of eosinophils in contrast to other leukocytes and thus permit gating on eosinophils without prior purification. Furthermore, the procedure does not alter the detection of cell surface antigens on eosinophils and simultaneous measurements of surface antigens and intracellular proteins is possible. We have used different clinical samples (peripheral blood, bone marrow cells) to demonstrate differences in the expression of ECP and EPO. We conclude that the detection of intracellular eosinophil proteins by flow cytometry is a rapid, easy and semiquantitative procedure which may be used to study their expression in diseases where eosinophils are involved.     

Flow cytometry and staining kinetics to monitor the G0/G1 transition

The phenanthridine dyes propidium iodide (PI) and ethidium bromide (EB) have contributed to make DNA quantitation a routine measurement by flow cytometry. As planar molecules they easily intercalate between base pairs of double stranded nucleic acids. When the quantity of dye exceeds the amount of DNA, the intensity of emitted fluorescence can be related to the amount of DNA. This is, in fact, the basic requirement of quantitative measurement. When staining is performed at low dye concentration and there are no sufficient molecules to saturate all the available DNA-binding sites, the emitted fluorescence, other than the true DNA quantity, may be dependent on the state of chromatin condensation. A staining procedure aimed to stress the influence of nuclear structure on the emitted fluorescence of PI is described. This is achieved by means of a very low dye concentration (<0.01 g/ml PI) to guarantee staining far below saturation condition. In this particular condition the staining rate slows down to be monitored by flow cytometry. As different experimental models the leucocytes of the normal human peripheral blood have been used taking into account the relatively condensed chromatin of granulocytes with respect to that of the mononuclear cells. Significantly higher fluorescence intensity have been obtained from mononuclear cells compared to that of the polymorphonuclear ones. Quiescent versus exponentially proliferating cell cultures had also been tested. In this staining condition low fluorescence intensity have been obtained by condensed chromatin structure (G₀) in comparison to the more decondensed (G₁) one.Abbreviations PI propidium iodide - PBS phosphate buffered saline - BrdU bromodeoxyuridyne - FCM flow cytometry - PMNC polymorphonuclear cells - MNC mononuclear cells     

Analysis of cytosolic and lysosomal pH in apoptotic cells by flow cytometry

Several reports indicate that the cytosol is acidified during apoptosis although the mechanism is not yet fully elucidated. The most acidic organelle found in the cell is the lysosome, raising the possibility that lysosomal proton release may contribute to the cytosolic acidification. We here describe methods for measurement of the cytosolic and lysosomal pH in U937 cells by a dual-emission ratiometric technique suitable for flow cytometry. Cytosolic pH was analysed in cells loaded with the fluorescent probe BCECF, while lysosomal pH was determined after endocytosis of FITC-dextran. Standard curves were obtained by incubating cells in buffers with different pH in the presence of the proton ionophore nigericin. Apoptosis was induced by exposure of cells to 10ng/ml TNF- for 4h, and apoptotic cells were identified using a fluorescent marker for active caspases. By gating of control and apoptotic cells, the cytosolic and lysosomal pH were calculated in each population. The cytosolic pH was found to decrease from 7.2 ± 0.1 to 5.8s±0.1 and the lysosomal increased from 4.3±0.4 to 5.2±0.3. These methods will be useful in future attempts to evaluate the involvement of lysosomes in the acidification of the cytosol during apoptosis.     

Expression and function of the Fas receptor on human blood and tissue eosinophils

The interaction between activated T cells and eosinophils has been proposed to play an important role in the pathogenesis of allergic diseases. T cell-derived cytokines such as interleukin-5 and granulocyte/macrophage colony-stimulating factor inhibit eosinophil apoptosis and may therefore contribute to the development of tissue and blood eosinophilia in these disorders. Withdrawal of these cytokines leads to eosinophil apoptosis in vitro. In contrast, the mechanisms which actively induce apoptosis in eosinophils are at present not completely understood. In this study, we demonstrate that freshly isolated human eosinophils express mRNA and protein for the Fas receptor. Using anti-Fas monoclonal antibody (mAb), we show that Fas activation accelerates apoptotic eosinophil death in vitro. Moreover, treatment of nasal polyps ex vivo with anti-Fas mAb decreased eosinophilic tissue inflammation. However, we observed that blood as well as tissue eosinophils derived from some eosinophilic donors do not express functional Fas receptors, although Fas protein is normally expressed in these cells. This implies that the susceptibility of the Fas receptor is a matter of regulation in eosinophils as previously observed in other systems. These data suggest that Fas ligand/Fas interactions are involved in the regulation of eosinophil apoptosis and that defects in this system could contribute to the accumulation of these cells in allergic and asthmatic diseases.     

Determination of mixed chimerism by a simple flow cytometry method

A simple, sensitive and accurate method was developed to determine the level of lymphoid chimerism in bone marrow-transplanted rodents. The method is based on flow cytometry using polyclonal alloantisera and labeled second step anti-IgG antibodies. Using mixtures of spleen cells from different mouse strains, it was demonstrated that low levels of chimeric cells (less than 1%) could easily be detected. Moreover, using two-color fluorescence analysis, the level of chimerism could also be determined in subpopulations of lymphoid cells, e.g., CD4 or CD8 cells and was found to be identical to the results obtained in unseparated lymphoid populations. The method was compared to the complement dependent cytotoxicity assay (CDCA) and to the flow cytometric determination of chimerism using labeled monoclonal antibodies against specific MHC antigens. CDCA was found to be more labor intensive and could only estimate the composition of the cell mixtures without detecting low levels of chimerism (< 5%). The results of flow cytometry, using directly labeled monoclonal antibodies or polyclonal antibodies with second step reagents, were identical.

It is concluded that, due to its simplicity and high sensitivity, the method described permits reliable determination of the level of mixed chimerism in rodents and is an excellent alternative when no anti-MHC mAbs are available.     

Effect of ketamine on apoptosis by energy deprivation in astroglioma cells using flow cytometry system

Apoptosis is a programmed, physiologic mode of cell death that plays an important role in tissue homeostasis. As for the central nervous system, ischemic insults can induce pathophysiologic cascade of apoptosis in neurophils. Impairment of astrocyte functions during brain ischemia can critically influence neuron survival by neuronglia interactions. We aimed to elucidate the protective effect of ketamine on apoptosis by energy deprivation in astrocytes. Ischemic insults was induced with iodoacetate/ carbonylcyanide m-chlorophenylhydrazone (IAA/CCCP) 1.5 mM/20 microm or 150 microm/2 microm for 1 hr in the HTB-15 and CRL-1690 astrocytoma cells. Then these cells were reperfused with normal media or ketamine (0.1 mM) containing media for 1 hr or 24 hr. FITC-annexin-V staining and propidium iodide binding were determined by using flow cytometry. Cell size and granularity were measured by forward and side light scattering properties of flow cytometry system, respectively. An addition of ketamine during reperfusion increased the proportion of viable cells. Ketamine alleviated cell shrinkage and increased granularity during the early period, and ameliorated cell swelling during the late reperfusion period. Ketamine may have a valuable effect on amelioration of early and late apoptosis in the astrocytoma cells, even though the exact mechanism remains to be verified.     

Annexin V联合PI染色法定量检测凋亡细胞

为评价ＡｎｎｅｘｉｎＶ／ＰＩ双参数法在凋亡检测中的价值,用ＰＩ染色法、ＴＵＮＥＬ法及双参数ＡｎｎｅｘｉｎＶ／ＰＩ法定量检测地塞米松处理小鼠胸腺细胞凋亡发生率。结果发现其凋亡检出率分别为ＰＩ法２７１９％,ＡｎｎｅｘｉｎＶ／ＰＩ法３２２８％,ＴＵＮＥＬ法５０１７％。三者之间均有显著差异（Ｐ＜００１）。但ＴＵＮＥＬ法不能将死亡细胞、凋亡细胞区分开来。ＡｎｎｅｘｉｎＶ／ＰＩ法可将正常细胞（ＡｎｎｅｘｉｎＶ ＰＩ ）、凋亡细胞（ＡｎｎｅｘｉｎＶ＋ＰＩ ）、死亡细胞（ＡｎｎｅｘｉｎＶ＋ＰＩ＋）分开来。ＡｎｎｅｘｉｎＶ／ＰＩ法能检出早期凋亡细胞且更为简单、灵敏、特异,是较为理想的凋亡定量检测方法。     

恶性肿瘤细胞多药耐药基因(MDR1)表达产物P170的流式细胞学的检测

目的，探讨用流式细胞免疫学检测恶性实体瘤组织及腹水细胞多药耐药基因（ＭＤＲ１）表达的方法和临床意义。方法：采用搓网方法，将１２种９４例不同的恶性肿瘤手术切除标本制成细胞膜完整的单细胞悬液，并从６例癌性腹水中提取富含癌细胞的悬液，再用流式细胞免疫学方法检测悬液中癌细胞ＭＤＲ１表达产物Ｐ１７０含量。结果：经所用方法制备悬液中的癌细胞丰富，杂质细胞少，荧光显微镜下观察细胞膜完整，Ｐ１７０阳性细胞抗体荧光位于细胞膜上。结论：研究恶性实体肿瘤细胞ＭＤＲ１表达是可行的，可明确其原始的药物敏感性，对临床化疗有重要价值     

A rapid method for infectivity titration of Andes hantavirus using flow cytometry

The focus assay is currently the most commonly used technique for hantavirus titer determination. This method requires an incubation time of between 5 and 11 days to allow the appearance of foci after several rounds of viral infection. The following work presents a rapid Andes virus (ANDV) titration assay, based on viral nucleocapsid protein (N) detection in infected cells by flow cytometry. To this end, an anti-N monoclonal antibody was used that was developed and characterized previously. ANDV N could be detected as early as 6 h post-infection, while viral release was not observed until 24–48 h post-infection. Given that ANDV detection was performed during its first round of infection, a time reduction for titer determination was possible and provided results in only two days. The viral titer was calculated from the percentage of N positive cells and agreed with focus assay titers. Furthermore, the assay was applied to quantify the inhibition of ANDV cell entry by patient sera and by preventing endosome acidification. This novel hantavirus titration assay is a highly quantitative and sensitive tool that facilitates infectivity titration of virus stocks, rapid screening for antiviral drugs, and may be further used to detect and quantify infectious virus in human samples.     

流式技术测定乙型肝炎患者外周血特异性CD8＋T细胞及其临床意义

目的 探讨流式细胞技术检测乙型肝炎患者HBV特异性CD8＋T细胞的水平并分析其临床意义.方法 采用HLA-A2分子胞外段与HBV核心表位肽core18-27结合的HLA-肽五聚体（Pentamers）对25例急性乙肝患者、35例慢性乙肝患者和10例正常健康人的外周血进行染色,设计流式细胞技术检测其针对该肽段的特异性CD8＋T细胞数量,以占总计数CD8＋细胞数的百分比表示.结果 12例HLA-A2＋的急性乙肝患者急性期可检测到高水平的特异性CD8＋T细胞,中位数为2.93%（1.12%～4.63%）,16例HLA-A2＋的慢性乙肝患者特异性CD8＋T细胞水平较低,中位数为0.75%（＜0.01%～1.76%）,两组之间差异有统计学意义（P＜0.01）.10例HLA-A2＋正常对照组、13例HLA-A2-急性乙肝对照组和19例HLA-A2慢性乙肝对照组的特异性CD8＋T细胞均不超过0.02%.结论 HLA-肽五聚体流式细胞技术能在体外直接检测HBV特异性的CD8＋T细胞数量,其水平可能影响着HBV感染者体内病毒的清除,且与乙肝的不同临床转归有关.     

流式细胞术在外周血嗜酸性粒细胞及其相关分子检测中的应用

目的 :应用流式细胞术 ,建立一种准确、外周血嗜酸性细胞及其相关分子的快速测定方法。方法 :采集正常人外周血 ,用茶碱 (10 -4mol/L)、地塞米松 (10 -4mol/L)和rhIL 5 (10 -8mol/L)预处理 ,用抗CD16 PEmAb与FITC标记的抗相关细胞分子的进行双标记染色 ,并以CD16 FL2辅助设门 ,准确找到嗜酸性粒细胞群 ,然后对其相关分子进行分析。结果 :嗜酸性粒细胞定位准确 ,茶碱和地塞米松能够抑制IL 5引起的Eos的活化并使其表面的CD6 2L脱落。结论 :应用流式细胞术与二色荧光mAbCD16 PE阴性细胞法设门 ,可准确快速地检测外周血中嗜酸性粒细胞及分子的表达率 ,血液用样量小 ,人为影响因素少 ,是免疫学基础研究和临床检验较理想的测定方法。     

Immunophenotyping of cytologic specimens by flow cytometry

Immunophenotyping by flow cytometry is well established as an ancillary technique in the diagnosis of hematopoietic neoplasms. However, flow cytometry is rarely performed on cytologic specimens because most cytologists are more comfortable with direct microscopy and believe that there is inadequate cellularity for analysis. Paradoxically, cytologic material is usually cell suspensions making it ideal for flow cytometry. In order to evaluate the usefulness of immunophenotyping cytologic specimens by flow cytometry, we retrospectively reviewed all cytologic specimens submitted to our flow cytometry unit from 1988 to 1991. Thirty-one cerebrospinal fluid specimens were analyzed. There were inadequate cells for analysis in 15 cases. Five showed a monoclonal proliferation; 11 were nondiagnostic. A range (r) of one to six cell surface markers were performed. Thirty-two body cavity fluids were analyzed: 7 peritoneal, 19 pleural, 2 pericardial, and 4 bronchoalveolar lavage. There were cells to analyze in all cases. Seven had a monoclonal proliferation; 25 were nondiagnostic (r = 4-21 markers performed). One hundred eighteen fine needle aspirates (FNA) were reviewed; 58 FNA were radiologically guided, 60 were superficial lesions. There were inadequate cells for analysis in two cases. Sixty-one demonstrated a monoclonal proliferation; 55 were nondiagnostic (r = 1-22 markers performed). We conclude that immunophenotyping by flow cytometry is of limited value for cerebrospinal fluid analysis and that knowledge of previous immunophenotyping studies is essential for correct analysis; analysis of body cavity fluids is easily performed but less often demonstrates a monoclonal proliferation. Immunophenotyping by flow cytometry is a valuable adjunctive technique for FNA and yields adequate cells for analysis.     

Chimaeric anti-CD4 monoclonal antibody cross-linked by monocyte Fcγ receptor mediates apoptosis of human CD4 lymphocytes

Previous studies have shown that murine anti-CD4 monoclonal antibody, cross-linked by rabbit anti-mouse immunoglobulin, could mediate apoptosis of murine CD4⁺ lymphocytes when they were stimulated by T cell receptor antibody. In this study, we have shown that the murine anti-CD4 monoclonal antibody, OKT4, can induce apoptosis in human CD4⁺ T cells stimulated by the recall antigen tuberculin purified protein derivative (PPD) only when cross-linked by rabbit anti-mouse immunoglobulin. The chimeric anti-CD4 monoclonal antibody, cM-T412 whose Fc fragment is human, was able to cause apoptosis without cross-linking by a second antibody. Similarly, abolition of PPD-induced proliferation of peripheral blood mononuclear cells by cM-T412 did not require cross-linking with rabbit anti-human immunoglobulin. Inhibition of proliferation by cM-T412 could be reduced by pre-treating monocytes with heat-aggregated human IgG. This suggested that monocyte Fcγ receptors might be cross-linking the human Fc of cM-T412. Propidium iodide staining together with immunofluorescence showed that the apoptotic cells were indeed CD4⁺ lymphocytes. It is proposed that during treatment with cM-T412 in autoimmune disease such as rheumatoid arthritis, cM-T412-coated CD4 T cells, when they are subsequently stimulated by the unknown arthritogenic antigen, may undergo apoptotic cell death through cross-linking of cM-T412 on Fey receptor-positive cells within the joint.     

一种新的检测细胞凋亡的多参数流式细胞分析方法

建立了一种新的检测细胞凋亡的多参数流式细胞分析方法.HL60白血病细胞株经化疗药物足叶乙甙处理后,加AnnexinV (AV)-FITC/PI孵育双染,用多参数流式细胞术检测细胞凋亡.结果显示,凋亡细胞的百分比随诱导时间的延长而逐渐增多.表明AV-FITC/PT双染法既能对细胞膜表面特异蛋白染色,又同时检测细胞膜完整性.多参数流式细胞术是一种快速、简便又准确的检测细胞凋亡的方法.     

New trends in affordable CD4+ T-cell enumeration by flow cytometry in HIV/AIDS

Inexpensive antiretroviral therapy (ART) might soon be available to treat human immunodeficiency virus (HIV) infections in resource-restricted areas of the globe. The number of CD4+ T-cells in the blood is the single most important laboratory parameter to select patients for therapy at the right time and to monitor the effect of ART. The question is asked whether flow cytometry is adaptable to change from an expensive and complicated scientific analytical instrumentation to become a practical diagnostic tool that can be widely operated. Recent studies indicate that a branch of clinical/practical flow cytometry is gaining a new identity by a confident simplification and improvement of clinical protocols. These new observations can be marshaled into three new areas of development. First, the changes in the choices of reagents and staining protocols have been initiated by the preferred use of primary immunological gating during the flow-cytometric analysis, exploiting the exquisite discriminating power of antibodies. The recent National Institutes of Health (NIH) and Centers for Disease Control and Prevention (CDC) guidelines introduced CD45-assisted protocols that are also at the heart of the PanLeucogating protocol that revitalized the testing of absolute CD4 counts on double-platform. With CD45 staining the leucocyte populations can be reliably studied in aging samples. It is now also documented that minimal technology, that is primary gating with CD4 (or CD8) antibodies, provides excellent CD4 (or CD8) T-cell counts. Consequently the optimal affordable protocol uses CD45 and CD4 antibodies in combination. The second area of development is the absolute counting facility on flow cytometers. Most frequently, microbeads are added to blood to define the sample volume in instruments that are not equipped with a volumetric microsyringe. The beads are, however, expensive, and the utilization of the stable flow rate of the excellent instruments might soon provide an answer to replace dear microbeads. With stable flow, the time span of analysis tells the sample volume and the absolute counts can be calculated. Finally, stabilized blood cell standards and blood stabilizing fluid, referred to as Transfix, have recently been introduced for quality assurance. These products are important to prove the precision and accuracy of the new affordable protocols and also to check, and guide if necessary, the performance of the laboratories even in remote areas. These recent developments provide evidence about the renaissance of affordable flow cytometry, a precise, costeffective and quantitative technology that is capable of providing CD4+ T-lymphocyte counts in as high volume as >400 patient assessment per day at the fraction of the cost of the current Western prices. These recent achievements need to be taken into consideration when alternative, nonflow CD4-counting methods are assessed.