O trabalho relatado neste artigo foi apoiado por uma Nacional de Saúde e Pesquisa Médica do Conselho (NHMRC) da Austrália Grant Program (CRP) e um Projeto NHMRC Grant (CRP e BJCQ). BJCQ também é um NHMRC Peter Doherty Fellow Pós-Doutorado.

1) Configuração de reagente 1.1) solução estoque CFSE O corante é CFSE compra diacetato carboxifluoresceína succinimidyl éster (CFDA, SE) (MW 557,47 g / mol), normalmente em 25 frascos mg. Dissolver a 25 mg em 8,96 mL de uma solução de DMSO estoque final de 5 mM (loja como 50-100 mL alíquotas a -20 ° C durante vários meses). CFDA, SE irá reagir com solução aquosa por isso, é fundamental que tal exposição ser evitadas durante o armazenamento. 1.2) Os linfócitos Isolar linfócitos de baço e gânglios linfáticos ou de ratos e ressuspender em 1 ml de meio de cultura (por exemplo, RPMI) com 5% inativado pelo calor (HI) de soro fetal bovino (FCS), com uma concentração celular de 0,5 x 06-10 outubro x 10 7 / mL. 2) Rotulagem CFSE 2.1 Método de rotina): <ol class="lalpha"><li> Completamente ressuspender as células no volume de 1 mL de meio e coloque cuidadosamente no fundo de um fresco (sem contato com o) tubo cônico de 10 mL. </li><li> Coloque o tubo horizontalmente (usando um tubo sem contato com o vai impedir a 1 ml de suspensão de células de se mover e prematuramente mistura com o, CFDA SE soluções). </li><li> Juntar cuidadosamente 110 mL de PBS para a parte não entram em contato com o plástico no topo do tubo que garante que não faz contato com a solução celular. </li><li> Ressuspender 1,1 mL do estoque de 5 mm de CFDA, SE na PBS 110 mL. </li><li> Rapidamente a tampa do tubo e inverter e vortex bem para obter uniforme rápida mistura das soluções. Note-se que o corante CFSE está em uma concentração final de 5 mM, no entanto, a concentração ótima pode ter que ser determinados para cada lote preparado, e então verificado a cada seis meses para garantir que ele é eficaz. </li><li> Incubar as células por 5 minutos em temperatura ambiente. Note-se que após a conversão do CFDA, SE a CFSE (ver discussão) torna-se o corante fluorescente e, portanto, propenso ao branqueamento pela exposição à luz excessiva. Assim, é aconselhável proteger o tubo da luz a partir deste ponto, por exemplo, cobrindo-o com papel alumínio. </li><li> Lave as células através da diluição em 10 volumes de 20 ° C PBS contendo 5% de HI FCS, sedimentando por centrifugação a 300 xg por 5 min a 20 ° C e descartando o sobrenadante. Repita lavar mais duas vezes. </li></ol> 2.2 O método alternativo), que também é adequado para um maior número de células (10 - 30 x 10 7): <ol class="lalpha"><li> Prepare um 2 x (10 mM) CFDA, SE solução pela adição de 2 mL do estoque mM 5-1 mL de PBS e rapidamente adicionar este a 1 mL de células ressuspenso cuidadosamente, em seguida, rapidamente a tampa do tubo e inverter e vortex bem para obter uniforme rápida mistura. </li><li> Incubar as células por 5 min à temperatura ambiente e lave como nos passos 2.1 (f) e 2.1 (g). </li></ol> 2.3) As células podem então ser aplicado a um protocolo de interesse para a indução da divisão celular. Células marcadas pode ser usado em ambos in vitro e em ensaios in vivo. 2.4) Ao término do ensaio de proliferação, as células são colhidas e analisadas por citometria de fluxo (veja abaixo exemplos representativos). 3) Resultados Representante Para avaliar a proliferação de linfócitos por diluição CFSE, é útil conhecer a fluorescência das células indivisível (ou seja, máximo de fluorescência) e não-rotulados células (ou seja, a fluorescência mínima). Portanto, seu projeto experimental deve levar em conta esses controles. Abaixo estão alguns exemplos de ensaios in vitro e em ensaios in vivo utilizando CFSE para medir T CD8 + a divisão celular por citometria de fluxo. 3.1) Em estimulação in vitro A Figura 1 mostra os perfis de CFSE CFSE marcado com ovalbumina (OVA) específicos de células T CD8 + receptor transgênicos OT-I de células T após três dias da cultura com as células dendríticas pulsadas com várias quantidades de OVA. Células T CD8 + purificada a partir do baço e gânglios linfáticos da OT-I ratos foram marcados com CFSE e 1 x 10 5 células cultivadas com 3,3 x 10 4 DC. DC, onde pulsava com OVA por 1 hora a 37 ° C e lavadas duas vezes antes da cultura. Após 3 dias, as células onde colhidas e rotulados com anti-CD8-APC anticorpos e Hoechst 33258 e depois analisados ​​por citometria de fluxo (50 mil eventos coletados). Live (Hoechst 33258 -) CD8 + células são mostrados. Como controles, as células CD8 + T cultivadas por si só, mostra a intensidade CFSE de não-dividida células, enquanto as células não-rotulados mostra a auto-fluorescência das células e os limites de divisões celulares detectáveis. Note-se que quatro picos CFSE pode ser visto em cada um dos painéis, neste exemplo, indicando que as células foram submetidas até 3 divisões. 3.2) Na estimulação vivo A Figura 2 mostra os perfis de CFSE CFSE marcado com receptor de células T OVA-específicas transgênicos CD8 + T OT-I células após 3 dias in vivo in a presença de 20 mg OVA. Células T CD8 + purificada a partir do baço e gânglios linfáticos da CD45.1 congênitas OT-I ratos foram marcados com CFSE e 5 x 10 6 células injetadas iv na veia lateral da cauda C56BL/6J (CD45.2 +) ratos. Depois de 2 hr camundongos foram injetados iv com 20 mg de OVA. Após 3 dias, baços de camundongos foram coletados, feita em uma suspensão de células individuais, rotulada com anti-B220-PerCP, anti-CD8-APC-Cy7 e anti-CD45.1-PE-Cy7 anticorpos e Hoechst 33258 e depois analisados por citometria de fluxo (1.000.000 eventos coletados). Live (Hoechst 33258 -) B220-células são mostrados no painel esquerdo e gated CD8 + + CD45.1 células mostrado no painel direito. Como controles, desestimulado CFSE marcado células T CD8 +, mostra a intensidade CFSE de não-dividida células, enquanto os não-rotulados células mostra a auto-fluorescência das células e os limites de divisões celulares detectáveis. Note que o uso da diferença CD45 allotypic é vital para resolver o CD8 + células T transferidos do host, como eles são um subconjunto menor do total de células CD8 + T (painel esquerdo). Note-se que a maioria das células cair dentro de 7 picos CFSE neste exemplo (painel direito), indicando que as células foram submetidas até 6 divisões. <img src="/files/ftp_upload/2259/2259fig1.jpg" alt="Figura 1" /> Figura 1. Capacidade de CFSE marcado com ovalbumina (OVA) específicos de células T do receptor transgênicos CD8 + células OT-I T para responder in vitro para DC pulsado com diferentes concentrações de OVA, os dados mostraram estar após três dias de cultura. Nota população não-dividida de CD8 + T células na ausência de antígeno (histograma cinza claro) e auto-fluorescência da população não-rotulados (histograma cinza escuro). A figura mostra células T CD8 + que têm dividido 1-3 vezes com base em picos de diluição CFSE, com mais células T dividindo nas concentrações mais elevadas de antígeno. <img src="/files/ftp_upload/2259/2259fig2.jpg" alt="Figura 2" /> Figura 2. Capacidade de CFSE marcado com ovalbumina (OVA) específicos de células T do receptor transgênicos células CD8 + OT-I T, quando adotivamente transferidos em camundongos C57BL / 6 para responder a OVA, os dados apresentados três dias após a transferência adotiva Painel esquerdo:. CD8 +, CD45. 1 + células T OT-1 em ratos destinatário. Painel da direita: perfil proliferação CFSE. Nota da população não-divididas de células T CD8 + em camundongos destinatário não receber o antígeno (histograma cinza claro) e auto-fluorescência de não-rotulados linfócitos (histograma cinza escuro). A figura mostra as células CD8 + T que têm dividido 1-6 vezes com base em picos de diluição CFSE. <img src="/files/ftp_upload/2259/2259fig3.jpg" alt="Figura 3" /> Figura 3. A representação dos vários eventos moleculares que ocorrem durante a marcação das células com diacetato carboxifluoresceína succinimidyl éster (CFDA, SE). Para mais detalhes do processo veja o texto de discussão. Nota: &#39;CFSE&#39; A sigla genérica, não CFDA, SE, é usado para descrever o reagente rotulagem e do processo de rotulagem em geral. Figura baseada em Parish 4.

<ol>
	<li>Lyons, A. B., Parish, C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determination+of+lymphocyte+division+by+flow+cytometry.">Determination of lymphocyte division by flow cytometry.</a> J. Immunol. Methods. 171, 131-137 (1994).</li><li>Parish, C. R., Glidden, M. H., Quah, B. J., Warren, H. S., Coligan, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+the+intracellular+fluorescent+dye+CFSE+to+monitor+lymphocyte+migration+and+proliferation.">Use of the intracellular fluorescent dye CFSE to monitor lymphocyte migration and proliferation.</a> Current protocols in immunology. , (2009).</li><li>Quah, B. J., Warren, H. S., Parish, C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monitoring+lymphocyte+proliferation+in+vitro+and+in+vivo+with+the+intracellular+fluorescent+dye+carboxyfluorescein+diacetate+succinimidyl+ester.">Monitoring lymphocyte proliferation in vitro and in vivo with the intracellular fluorescent dye carboxyfluorescein diacetate succinimidyl ester.</a> Nature Protocols. 2, 2049-2056 (2007).</li><li>Parish, C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorescent+dyes+for+lymphocyte+migration+and+proliferation+studies.">Fluorescent dyes for lymphocyte migration and proliferation studies.</a> Immunol Cell Biol. 77, 499-508 (1999).</li></ol>

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, A fim de apreciar como funciona e porque CFSE rotulagem uniforme, rápido é necessário para seu uso na análise de proliferação, é útil para compreender a base molecular da célula CFSE rotulagem. Isto pode ser dividido em duas fases, 1) entrada de célula e 2) rotulagem Protein (Figura 3). 1) entrada Cell: Entrada do corante para a célula é mediada pela forma diacetilados do corante, diacetato carboxifluoresceína succinimidyl éster (CFDA, SE). Os acetatos fazer a membrana permeante corante altamente permitindo seu fluxo rápido através da membrana plasmática. Esterases, presente dentro da célula, pegará o acetatos de CFDA, SE e, assim, dar lugar à forma CFSE do corante que é permeante de membranas muito menos, portanto, concentrar o corante dentro da célula. 2) rotulagem Proteína: Embora ambos CFDA, SE e CFSE têm amino-reativa cadeias laterais succinimidyl, apenas o CFSE é fluorescente. A alta concentração intracelular de CFSE facilita rotulagem nível rápido e de alta intracelular de proteínas. Rotulagem CFSE de células deve ser realizada rapidamente, a fim de obter uma população homogênea rotulados de células, que é crítico para a resolução de células que sofreram diversas divisões, como mostrado nos resultados representativos (Figura 1 e 2).

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<td>CFDA,SE</td>
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<td>Molecular Probes</td>
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<td>DMSO</td>
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<td>Cambridge Isotope Laboratories Inc.</td>
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<td>Lymphocytes</td>
<td>&nbsp;</td>
<td>eg mouse or human</td>
<td>&nbsp;</td>
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<td>&nbsp;</td>
<td>Gibco</td>
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the use of carboxyfluorescein diacetate succinimidyl ester (cfse) to monitor lymphocyte proliferation

Carboxifluoresceína succinimidyl éster (CFSE) é um meio eficaz e popular para monitorar de linfócitos divisão 1-3. CFSE covalentemente rótulos de longa duração de moléculas intracelulares com o corante fluorescente, carboxifluoresceína. Assim, quando uma célula se divide CFSE marcado, a sua progenitura são dotados de metade do número de carboxifluoresceína marcadas moléculas e, assim, cada divisão celular pode ser avaliada medindo a diminuição correspondente na fluorescência celular via citometria de fluxo. A capacidade de CFSE para rotular as populações de linfócitos com uma alta intensidade fluorescente de variância excepcionalmente baixo, juntamente com a sua baixa toxicidade celular, torná-lo um corante ideal para medir a divisão celular. Uma vez que é um corante de fluoresceína baseado também é compatível com uma ampla variedade de fluorocromos outras que a torna aplicável a multi-cor citometria de fluxo. Este artigo descreve os procedimentos normalmente utilizados para a rotulagem linfócitos do mouse com a finalidade de monitorar até 8 divisões celulares. Estas células marcadas pode ser usado tanto para in vitro e in vivo.

Watch this Scientific Journal Video about The Use of Carboxyfluorescein Diacetate Succinimidyl Ester CFSE to Monitor Lymphocyte Proliferation at JoVE.com

The Use of Carboxyfluorescein Diacetate Succinimidyl Ester CFSE to Monitor Lymphocyte Proliferation

CFSE covalentemente rótulos de longa duração de moléculas intracelulares com o corante fluorescente, carboxifluoresceína. Como tal, quando uma célula se divide CFSE marcado, a sua progenitura têm metade da quantidade de fluorescência, que pode assim ser utilizada para avaliar a divisão celular. Este artigo descreve os procedimentos normalmente utilizados para a rotulagem linfócitos mouse com CFSE.

O Uso de diacetato carboxifluoresceína Succinimidyl Ester (CFSE) para monitorar a proliferação de linfócitos

Carboxyfluorescein succinimidyl ester (CFSE) is an effective and popular means to monitor lymphocyte division1-3.  CFSE covalently labels long-lived ...

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Nanyang Technological University

Research

JoVE Journal

Immunology and Infection

The Use of Carboxyfluorescein Diacetate Succinimidyl Ester (CFSE) to Monitor Lymphocyte Proliferation

91.7K visualizações.  John Curtin School of Medical Research, Australian National University. CFSE covalentemente rótulos de longa duração de moléculas intracelulares com o corante fluorescente, carboxifluoresceína. Como tal, quando uma célula se divide CFSE marcado, a sua progenitura têm metade da quantidade de fluorescência, que pode assim ser utilizada para avaliar a divisão celular. Este artigo descreve os procedimentos normalmente utilizados para a rotulagem linfócitos mouse com CFSE.

Vídeo: The Use of Carboxyfluorescein Diacetate Succinimidyl Ester CFSE to Monitor Lymphocyte Proliferation

Antigen Specific In Vivo Killing Assay using CFSE Labeled Target Cells

Carboxyfluorescein diacetate succinimidyl ester (CFSE) can be used to easily and quickly label a cell population of interest for in vivo investigation. This labeling has classically been used to study proliferation and migration. In the method presented here, we have shortened the timeline after adoptive transfer to look at survival and killing of epitope specific CFSE labeled target cells4-6. The level of specific killing of a CD8 + T cell clone can indicate the quality of the response, as their quantity may be misleading. Specific CD8+ T cells can become functionally exhausted over time with a decline in cytokine production and killing7,8. Also, certain CD8 + T cell clones may not kill as well as others with differing TCR specificities9. For effective Cell Mediated Immunity (CMI), antigens must be identified that produce not only adequate numbers of responding T cells, but also functionally robust responding T cells. Here we assess the percent cell specific killing of two peptide specific T cell clones in BALB/c mice.

Antigen Specific In Vivo Killing Assay using CFSE Labeled Target Cells

Many infections elicit a strong CTL response, but occasionally, the quantity of responding cells does not correlate to control of the pathogen1. One measure of CTL quality is their ability to kill specifically2. CFSE labeling of target cells can be used to investigate this CTL response quality in vivo3,4.

Specific Antigen In Vivo Ensaio Killing usando células CFSE rotuladas Alvo

Carboxyfluorescein diacetate succinimidyl ester (CFSE) can be used to easily and quickly label a cell population of interest for in vivo investigation.  ...

Imunologia e Infecção

Finger-stick Blood Sampling Methodology for the Determination of Exercise-induced Lymphocyte Apoptosis

Exercise is a physiological stimulus capable of inducing apoptosis in immune cells. To date, various limitations have been identified with the measurement of this phenomenon, particularly relating to the amount of time required to isolate and treat a blood sample prior to the assessment of cell death. Because of this, it is difficult to determine whether reported increases in immune cell apoptosis can be contributed to the actual effect of exercise on the system, or are a reflection of the time and processing necessary to eventually obtain this measurement. In this article we demonstrate a rapid and minimally invasive procedure for the analysis of exercise-induced lymphocyte apoptosis. Unlike other techniques, whole blood is added to an antibody panel immediately upon obtaining a sample. Following the incubation period, red blood cells are lysed and samples are ready to be analyzed. The use of a finger-stick sampling procedure reduces the volume of blood required, and minimizes the discomfort to subjects.

Exercise is capable of inducing apoptosis in immune cells. There are various measurement limitations, particularly relating to the amount of time required to isolate and treat a blood sample prior to the assessment. Demonstrated is a rapid and minimally invasive procedure for the analysis of exercise-induced lymphocyte apoptosis.

Ponta de dedo Metodologia de amostragem de sangue para a determinação da apoptose induzida pelo exercício de Linfócitos

Exercise is a physiological stimulus capable of inducing apoptosis in immune cells. To date, various limitations have been identified with the measurement ...

A Visual Assay to Monitor T6SS-mediated Bacterial Competition

Type VI secretion systems (T6SSs) are molecular nanomachines allowing Gram-negative bacteria to transport and inject proteins into a wide variety of target cells1,2. The T6SS is composed of 13 core components and displays structural similarities with the tail-tube of bacteriophages3. The phage uses a tube and a puncturing device to penetrate the cell envelope of target bacteria and inject DNA. It is proposed that the T6SS is an inverted bacteriophage device creating a specific path in the bacterial cell envelope to drive effectors and toxins to the surface. The process could be taken further and the T6SS device could perforate other cells with which the bacterium is in contact, thus injecting the effectors into these targets. The tail tube and puncturing device parts of the T6SS are made with Hcp and VgrG proteins, respectively4,5.
The versatility of the T6SS has been demonstrated through studies using various bacterial pathogens. The Vibrio cholerae T6SS can remodel the cytoskeleton of eukaryotic host cells by injecting an "evolved" VgrG carrying a C-terminal actin cross-linking domain6,7. Another striking example was recently documented using Pseudomonas aeruginosa which is able to target and kill bacteria in a T6SS-dependent manner, therefore promoting the establishment of bacteria in specific microbial niches and competitive environment8,9,10.
In the latter case, three T6SS-secreted proteins, namely Tse1, Tse2 and Tse3 have been identified as the toxins injected in the target bacteria (Figure 1). The donor cell is protected from the deleterious effect of these effectors via an anti-toxin mechanism, mediated by the Tsi1, Tsi2 and Tsi3 immunity proteins8,9,10. This antimicrobial activity can be monitored when T6SS-proficient bacteria are co-cultivated on solid surfaces in competition with other bacterial species or with T6SS-inactive bacteria of the same species8,11,12,13.
The data available emphasized a numerical approach to the bacterial competition assay, including time-consuming CFU counting that depends greatly on antibiotic makers. In the case of antibiotic resistant strains like P. aeruginosa, these methods can be inappropriate. Moreover, with the identification of about 200 different T6SS loci in more than 100 bacterial genomes14, a convenient screening tool is highly desirable. We developed an assay that is easy to use and requires standard laboratory material and reagents. The method offers a rapid and qualitative technique to monitor the T6SS-dependent bactericidal/bacteriostasis activity by using a reporter strain as a prey (in this case Escherichia coli DH5&alpha;) allowing a-complementation of the lacZ gene. Overall, this method is graphic and allows rapid identification of T6SS-related phenotypes on agar plates. This experimental protocol may be adapted to other strains or bacterial species taking into account specific conditions such as growth media, temperature or time of contact.

We describe a qualitative assay to monitor bacterial competition mediated by the Pseudomonas aeruginosa type VI secretion system (T6SS). The assay relies on the survival/killing of Escherichia coli target cells carrying a lacZ-reporter. This technique is adjustable to assess the bactericidal/bacteriostasis activity of T6SS-proficient microorganisms.

Um Ensaio visual para o Monitor T6SS mediada Competição bacteriana

Type VI secretion systems (T6SSs) are molecular  nanomachines allowing Gram-negative bacteria to transport and inject proteins  into a wide variety of ...

Use of In vivo Imaging to Monitor the Progression of Experimental Mouse Cytomegalovirus Infection in Neonates

Human Cytomegalovirus (HCMV or HHV-5) is a life-threatening pathogen in immune-compromised individuals. Upon congenital or neonatal infection, the virus can infect and replicate in the developing brain, which may induce severe neurological damage, including deafness and mental retardation. Despite the potential severity of the symptoms, the therapeutic options are limited by the unavailability of a vaccine and the absence of a specific antiviral therapy. Furthermore, a precise description of the molecular events occurring during infection of the central nervous system (CNS) is still lacking since observations mostly derive from the autopsy of infected children. Several animal models, such as rhesus macaque CMV, have been developed and provided important insights into CMV pathogenesis in the CNS. However, despite its evolutionary proximity with humans, this model was limited by the intracranial inoculation procedure used to infect the animals and consistently induce CNS infection. Furthermore, ethical considerations have promoted the development of alternative models, among which neonatal infection of newborn mice with mouse cytomegalovirus (MCMV) has recently led to significant advances. For instance, it was reported that intraperitoneal injection of MCMV to Balb/c neonates leads to infection of neurons and glial cells in specific areas of the brain. These findings suggested that experimental inoculation of mice might recapitulate the deficits induced by HCMV infection in children. Nevertheless, a dynamic analysis of MCMV infection of neonates is difficult to perform because classical methodology requires the sacrifice of a significant number of animals at different time points to analyze the viral burden and/or immune-related parameters. To circumvent this bottleneck and to enable future investigations of rare mutant animals, we applied in vivo imaging technology to perform a time-course analysis of the viral dissemination in the brain upon peripheral injection of a recombinant MCMV expressing luciferase to C57Bl/6 neonates.

Use of In vivo Imaging to Monitor the Progression of Experimental Mouse Cytomegalovirus Infection in Neonates

Human Cytomegalovirus (HCMV) infection of neonates represents an important cause of mental retardation, yet the molecular events leading to virus-induced pathogenesis are still poorly understood. To investigate the dynamics of brain infection, we adapted whole-animal in vivo imaging to perform time-course analysis of neonates infected with a luciferase-recombinant virus.

Utilização de<em&gt; In vivo</em&gt; Imagem para monitorar a progressão da infecção pelo citomegalovírus Experimental Rato em recém-nascidos

Human Cytomegalovirus (HCMV or HHV-5) is a life-threatening  pathogen in immune-compromised individuals. Upon congenital or neonatal  infection, the virus ...

Using Fluorescent Proteins to Monitor Glycosome Dynamics in the African Trypanosome

Trypanosoma brucei is a kinetoplastid parasite that causes human African trypanosomiasis (HAT), or sleeping sickness, and a wasting disease, nagana, in cattle1. The parasite alternates between the bloodstream of the mammalian host and the tsetse fly vector. The composition of many cellular organelles changes in response to these different extracellular conditions2-5.
Glycosomes are highly specialized peroxisomes in which many of the enzymes involved in glycolysis are compartmentalized. Glycosome composition changes in a developmental and environmentally regulated manner4-11. Currently, the most common techniques used to study glycosome dynamics are electron and fluorescence microscopy; techniques that are expensive, time and labor intensive, and not easily adapted to high throughput analyses.
To overcome these limitations, a fluorescent-glycosome reporter system in which enhanced yellow fluorescent protein (eYFP) is fused to a peroxisome targeting sequence (PTS2), which directs the fusion protein to glycosomes12, has been established. Upon import of the PTS2eYFP fusion protein, glycosomes become fluorescent. Organelle degradation and recycling results in the loss of fluorescence that can be measured by flow cytometry. Large numbers of cells (5,000 cells/sec) can be analyzed in real-time without extensive sample preparation such as fixation and mounting. This method offers a rapid way of detecting changes in organelle composition in response to fluctuating environmental conditions.

Glycosome dynamics in African trypanosomes are difficult to study by traditional cell biology techniques such as electron and fluorescence microscopy. As a means of observing dynamic organelle behavior, a fluorescent-organelle reporter system has been used in conjunction with flow cytometry to monitor real-time glycosome dynamics in live parasites.

Utilizando Proteínas Fluorescentes para monitorar glicossomo Dynamics do Trypanosoma Africano

Trypanosoma brucei is a kinetoplastid parasite that causes human African trypanosomiasis (HAT), or sleeping sickness, and a wasting disease, nagana, in ...

Immunofluorescence to Monitor the Cellular Uptake of Human Lactoferrin and its Associated Antiviral Activity Against the Hepatitis C Virus

Immunofluorescence is a laboratory technique commonly used to study many aspects of biology. It is typically used to visualize the distribution and/or localization of a target molecule in cells and tissues. Immunofluorescence relies on the specificity of fluorescent-labelled antibodies against their corresponding antigens within a cell. Both direct and indirect immunofluorescence approaches can be used which rely on the use of antibodies linked with a fluorochrome. Direct immunofluorescence is less frequently used because it provides lower signal, involves higher cost and less flexibility. In contrast, indirect immunofluorescence is more commonly used because of its high sensitivity and provides an amplified signal since more than one secondary antibody can attach to each primary antibody. In this manuscript, both epifluorescence microscopy and confocal microscopy were used to monitor the internalization of human lactoferrin, an important component of the immune system, into hepatic cells. Moreover, we monitored the inhibitory potential of hLF on the intracellular replication of the Hepatitis C virus using immunofluorescence. Both the advantages and disadvantages associated with these approaches are discussed.

The human lactoferrin (hLF) is a component of the immune system. In this study, immunofluorescence assays are used to demonstrate both the hepatocellular uptake of hLF and a qualitative reduction in the hepatitis C virus replication upon treatment with hLF.

Imunofluorescência para monitorar a Incorporação celular de lactoferrina humana e sua Associated atividade antiviral contra o vírus da hepatite C

Immunofluorescence is a laboratory technique commonly used to study many aspects of biology. It is typically used to visualize the distribution and/or ...

The Use of Flow Cytometry to Assess the State of Chromatin in T Cells

During a proper immune response, quiescent T cells become activated upon antigen presentation to their antigen-specific T cell receptor. This leads to clonal proliferation of only those T cells that bear a receptor that recognizes the antigen. Chromatin decondensation is a hallmark of T cell activation and is required for T cells to acquire the ability to proliferate after antigen engagement. This change in chromatin condensation can be detected using antibodies raised against histone proteins. These antibodies cannot bind to their epitopes in na&#239;ve T cells as well as they can in activated T cells. We describe how to simultaneously stain T cell-specific surface markers, track viability with a fixable dead cell stain, and measure chromatin status via intracellular staining of Histone H3 proteins. Stained cells are analyzed by flow cytometry and chromatin condensation status is measured as the mean fluorescence intensity (MFI) of the Histone H3 stain. Chromatin decondensation during T cell activation is demonstrated as an increase in the MFI

Flow cytometry can be utilized to assess the state of chromatin within T cells. This protocol allows scientists to interpret evidence of chromatin decondensation during T cell activation demonstrated by an increase in the mean florescence intensity (MFI) of fluorescent Histone H3 antibodies

A citometria de fluxo para avaliar o estado de cromatina em células T

During a proper immune response, quiescent T cells become activated upon antigen presentation to their antigen-specific T cell receptor. This leads to ...

Detection of Trypanosoma brucei Variant Surface Glycoprotein Switching by Magnetic Activated Cell Sorting and Flow Cytometry

Trypanosoma brucei, a protozoan parasite that causes both Human and Animal African Trypanosomiasis (known as sleeping sickness and nagana, respectively) cycles between a tsetse vector and a mammalian host. It evades the mammalian host immune system by periodically switching the dense, variant surface glycoprotein (VSG) that covers its surface. The detection of antigenic variation in Trypanosoma brucei can be both cumbersome and labor intensive. Here, we present a method for quantifying the number of parasites that have 'switched' to express a new VSG in a given population. The parasites are first stained with an antibody against the starting VSG, and then stained with a secondary antibody attached to a magnetic bead. Parasites expressing the starting VSG are then separated from the rest of the population by running the parasites over a column attached to a magnet. Parasites expressing the dominant, starting VSG are retained on the column, while the flow-through contains parasites that express a new VSG as well as some contaminants expressing the starting VSG. This flow-through population is stained again with a fluorescently labeled antibody against the starting VSG to label contaminants, and propidium iodide (PI), which labels dead cells. A known number of absolute counting beads that are visible by flow cytometry are added to the flow-through population. The ratio of beads to number of cells collected can then be used to extrapolate the number of cells in the entire sample. Flow cytometry is used to quantify the population of switchers by counting the number of PI negative cells that do not stain positively for the starting, dominant VSG. The proportion of switchers in the population can then be calculated using the flow cytometry data.

Detection of Trypanosoma brucei Variant Surface Glycoprotein Switching by Magnetic Activated Cell Sorting and Flow Cytometry

African trypanosomes grown in vitro undergo antigenic variation at a low rate, such that populations are made up of parasites expressing a dominant variant surface glycoprotein (VSG) type and a small population of "switched" variants. This protocol describes a fast method for detecting and quantifying these populations.

detecção de<em&gt; Trypanosoma brucei</em&gt; Switching Variant glicoproteína de superfície por Magnetic celular ativado Seleção e citometria de fluxo

Trypanosoma brucei, a protozoan parasite that causes both Human and Animal African Trypanosomiasis (known as sleeping sickness and nagana, respectively) ...

Development of a Hepatitis B Virus Reporter System to Monitor the Early Stages of the Replication Cycle

Currently, it is possible to construct recombinant forms of various viruses, such as human immunodeficiency virus 1 (HIV-1) and hepatitis C virus (HCV), that carry foreign genes such as a reporter or marker protein in their genomes. These recombinant viruses usually faithfully mimic the life cycle of the original virus in infected cells and exhibit the same host range dependence. The development of a recombinant virus enables the efficient screening of inhibitors and the identification of specific host factors. However, to date the construction of recombinant hepatitis B virus (HBV) has been difficult because of various experimental limitations. The main limitation is the compact genome size of HBV, and a fairly strict genome size that does not exceed 1.3 genome sizes, that must be packaged into virions. Thus, the size of a foreign gene to be inserted should be smaller than 0.4 kb if no deletion of the genome DNA is to be performed. Therefore, to overcome this size limitation, the deletion of some HBV DNA is required. Here, we report the construction of recombinant HBV encoding a reporter gene to monitor the early stage of the HBV replication cycle by replacing part of the HBV core-coding region with the reporter gene by deleting part of the HBV pol coding region. Detection of recombinant HBV infection, monitored by the reporter activity, was highly sensitive and less expensive than detection using the currently available conventional methods to evaluate HBV infection. This system will be useful for a number of applications including high-throughput screening for the identification of anti-HBV inhibitors, host factors and virus-susceptible cells.

Here we describe a newly developed hepatitis B virus (HBV) reporter system to monitor the early stages of the HBV life cycle. This simplified in vitro system will aid in the screening of anti-HBV agents using a high-throughput strategy.

Desenvolvimento de um Sistema Reporter vírus da hepatite B de acompanhar as fases iniciais do ciclo de replicação

Currently, it is possible to construct recombinant forms of various viruses, such as human immunodeficiency virus 1 (HIV-1) and hepatitis C virus (HCV), ...

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

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

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

Dextran aumenta a eficiência de Lentivirus transdução das células NK primário murino e humano

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