Esta investigación fue financiada por una beca de la Facultad Nuevo en el Consejo de Becas de la Facultad en la Universidad de Western Kentucky.

1. Punción en el dedo de muestra de sangre <ol><li> Recolección de sangre entera se toma típicamente en reposo por una medida de referencia (normalmente después de 10-15 minutos de descanso sentado), durante o inmediatamente después de una sesión de ejercicio, y durante todo el período post-ejercicio (por lo general a partir de 1-3 horas tras el cese de la ejercicio). </li><li> Utilizando las precauciones universales, en primer lugar esterilizar la yema del dedo con el 70% de alcohol isopropílico. </li><li> Punción A continuación, el sitio usando una lanceta automatizado o dispositivo similar. A pesar de que el uso de una lanceta de calibre 30 para proporcionar la comodidad tema, una aguja de calibre grande podrían ser utilizados. </li><li> Limpie la primera gota de sangre, y luego recoger la sangre en tubos capilares o microvettes tratados con heparina de litio para evitar la coagulación. </li></ol> 2. Fenotipo celular y la apoptosis de tinción <ol><li> Añadir 10 l de sangre entera heparinizada al panel de anticuerpos tituló en 250 l de tampón de unión (véase el cuadro 1 esquema). Hemos utilizado un factor de dilución 1:20 con éxito, pero cada laboratorio debe su título de reactivos para determinar la mejor solución de trabajo. Tabla 1. Anticuerpos del panel para la determinación de la apoptosis inducida por el ejercicio en subconjuntos de leucocitos. Principios de la apoptosis se define por la expresión de anexina V, mientras que la apoptosis tarde fue definida por el doble etiquetado positivo con anexina V y 7-AAD. Las células necróticas se anexina V y 7-AAD + sólo las células. <table border="1"><tbody><tr><td> Un tubo </td><td> Tubo 2 </td><td> Tubo 3 </td><td> Tubo de 4 </td></tr><tr><td> Las únicas células del tubo </td><td> Anexina V - FITC </td><td> Anexina V - FITC </td><td> Anexina V - FITC </td></tr><tr><td></td><td> Contra CD4 Humanos - PE </td><td> Anti-CD8 Humanos - PE </td><td> Contra CD19 humano - PE </td></tr><tr><td></td><td> 7-AAD </td><td> 7-AAD </td><td> 7-AAD </td></tr><tr><td></td><td> Humanos contra CD45RA - APC </td><td> Humanos contra CD45RA - APC </td><td></td></tr></tbody></table> 7-AAD = 7-amino-actinomicina D, APC = aloficocianina, CD4 = linfocitos T, CD8 = supresor / linfocitos T citotóxicos, CD19 = linfocitos B, CD45RA = subconjuntos de células ingenuas, FITC = isotiocianato de fluoresceína, ficoeritrina = PE. </li><li> Incube a temperatura ambiente en la oscuridad durante 30 minutos. </li><li> Centrifugar a 1075 g durante 5-10 minutos. </li><li> Se decanta, añadir 300 l Glóbulos Rojos tampón de lisis, y completamente vórtice. </li><li> Incubar a temperatura ambiente durante 15 minutos. </li><li> Añadir 300 l de PBS para detener la reacción RBC lisis. </li><li> Centrifugar a 1075 g durante 5-10 minutos. </li><li> Se decanta, rack, y se añaden 50 l de tampón de unión. </li><li> Analizar por citometría de flujo. </li></ol> Se recomienda que, como mínimo, los siguientes controles se utilizaron: un tubo de células sólo para servir como un control negativo en la detección de autofluorescencia de fondo, y tubos que contienen cada uno fluorocromo para ajustar la compensación de la preparación inicial del citómetro de flujo. Además, se han utilizado cuentas de compensación estándar con éxito para crear nuestros experimentos.

<ol>
	<li>Simpson, R. J., Florida-James, G. D., Whyte, G. P., Black, J. R., Ross, J. A., Guy, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Apoptosis+does+not+contribute+to+the+blood+lymphocytopenia+observed+after+intensive+and+downhill+treadmill+running+in+humans.">Apoptosis does not contribute to the blood lymphocytopenia observed after intensive and downhill treadmill running in humans.</a> Res. Sports Med. 15, 157-174 (2007).</li><li>Steensberg, A., Morrow, J., Toft, A. D., Bruunsgaard, H., Pedersen, B. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prolonged+exercise,+lymphocyte+apoptosis+and+F2-isoprostanes.">Prolonged exercise, lymphocyte apoptosis and F2-isoprostanes.</a> Eur. J. Appl. Physiol. 87, 38-42 (2002).</li><li>Mooren, F. C., Bloming, D., Lechtermann, A., Lerch, M. M., V&#246;lker, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lymphocyte+apoptosis+after+exhaustive+and+moderate+exercise.">Lymphocyte apoptosis after exhaustive and moderate exercise.</a> J. Appl. Physiol. 93, 147-153 (2002).</li><li>Peters, E. M., Eden, M. V. a. n., Tyler, N., Ramautar, A., Chutergoon, A. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prolonged+exercise+does+not+cause+lymphocyte+DNA+damage+or+increased+apoptosis+in+well-trained+endurance+athletes.">Prolonged exercise does not cause lymphocyte DNA damage or increased apoptosis in well-trained endurance athletes.</a> Eur. J. Appl. Physiol. 98, 124-131 (2006).</li><li>Wang, J. -. S., Huang, Y. -. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+exercise+intensity+on+lymphocyte+apoptosis+induced+by+oxidative+stress+in+men.">Effects of exercise intensity on lymphocyte apoptosis induced by oxidative stress in men.</a> Eur. J. Appl. Physiol. 95, 290-291 (2005).</li><li>Mooren, F. C., Lechtermann, A., V&#246;lker, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exercise-induced+apoptosis+of+lymphocytes+depends+on+training+status.">Exercise-induced apoptosis of lymphocytes depends on training status.</a> Med. Sci. Sports Exerc. 36, 1476-1483 (2004).</li><li>Navalta, J. W., Sedlock, D. A., Park, K. -. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Blood+treatment+influences+the+yield+of+apoptotic+lymphocytes+after+maximal+exercise.">Blood treatment influences the yield of apoptotic lymphocytes after maximal exercise.</a> Med. Sci. Sports Exerc. 37, 369-373 (2005).</li></ol>

Un procedimiento de recogida de muestras de invasión mínima y su posterior análisis se demuestra en el análisis de las fases temprana y tardía inducida por el ejercicio de la apoptosis de los linfocitos. También es posible excluir con claridad las células, que son necrosis, apoptosis y no. Este procedimiento supera los inconvenientes y las molestias asociadas con la punción venosa invasiva de la región antecubital en múltiples momentos antes, durante e inmediatamente después del ejercicio, o asegurar un caté...

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<td>Flow Cytometry Binding Buffer</td>
<td>&nbsp;</td>
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finger-stick blood sampling methodology for the determination of exercise-induced lymphocyte apoptosis

El ejercicio es un estímulo fisiológico capaz de inducir la apoptosis en las células inmunes. Hasta la fecha, diversas limitaciones han sido identificados con la medición de este fenómeno, especialmente en relación con la cantidad de tiempo necesario para aislar y tratar a una muestra de sangre antes de la evaluación de la muerte celular. Debido a esto, es difícil determinar si los aumentos reportados en la apoptosis de las células inmunitarias se puede contribuir al efecto real del ejercicio sobre el sistema, o son un reflejo de la época y el procesamiento necesario para obtener finalmente esta medida. En este artículo se demuestra un procedimiento rápido y mínimamente invasivo para el análisis del ejercicio de la apoptosis inducida por linfocitos. A diferencia de otras técnicas, la sangre entera se añade a un panel de anticuerpos inmediatamente después de obtener una muestra. Tras el período de incubación, los glóbulos rojos son lisadas y las muestras están listas para ser analizadas. El uso de un procedimiento de muestreo del dedo reduce el volumen de sangre requerido, y reduce al mínimo las molestias a los sujetos.

Watch this Scientific Journal Video about Finger-stick Blood Sampling Methodology for the Determination of Exercise-induced Lymphocyte Apoptosis at JoVE.com

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

El ejercicio es capaz de inducir la apoptosis en las células inmunes. Hay varias limitaciones de medición, especialmente en relación con la cantidad de tiempo necesario para aislar y tratar a una muestra de sangre antes de la evaluación. Demostrado es un procedimiento rápido y mínimamente invasivo para el análisis de la apoptosis inducida por el ejercicio de linfocitos.

Punción en el dedo de sangre Metodología de muestreo para la determinación de la inducida por el ejercicio apoptosis de los linfocitos

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

finger-stick-blood-sampling-methodology-for-determination-exercise

Research

JoVE Journal

Immunology and Infection

12.1K vistas.  Western Kentucky University. El ejercicio es capaz de inducir la apoptosis en las células inmunes. Hay varias limitaciones de medición, especialmente en relación con la cantidad de tiempo necesario para aislar y tratar a una muestra de sangre antes de la evaluación. Demostrado es un procedimiento rápido y mínimamente invasivo para el análisis de la apoptosis inducida por el ejercicio de linfocitos.

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

Depletion of Specific Cell Populations by Complement Depletion

The purification of immune cell populations is often required in order to study their unique functions. In particular, molecular approaches such as real-time PCR and microarray analysis require the isolation of cell populations with high purity. Commonly used purification strategies include fluorescent activated cell sorting (FACS), magnetic bead separation and complement depletion. Of the three strategies, complement depletion offers the advantages of being fast, inexpensive, gentle on the cells and a high cell yield. The complement system is composed of a large number of plasma proteins that when activated initiate a proteolytic cascade culminating in the formation of a membrane-attack complex that forms a pore on a cell surface resulting in cell death1. The classical pathway is activated by IgM and IgG antibodies and was first described as a mechanism for killing bacteria. With the generation of monoclonal antibodies (mAb), the complement cascade can be used to lyse any cell population in an antigen-specific manner. Depletion of cells by the complement cascade is achieved by the addition of complement fixing antigen-specific antibodies and rabbit complement to the starting cell population. The cells are incubated for one hour at 37&deg;C and the lysed cells are subsequently removed by two rounds of washing. MAb with a high efficiency for complement fixation typically deplete 95-100% of the targeted cell population. Depending on the purification strategy for the targeted cell population, complement depletion can be used for cell purification or for the enrichment of cell populations that then can be further purified by a subsequent method.

To effectively study the function of immune cell populations their purification is often required. Complement depletion is a fast and inexpensive technique for the isolation of immune cell populations with high purity.

El agotamiento de las poblaciones de células específicas por el agotamiento del complemento

The purification of immune cell populations is often required in order to study their unique functions.  In particular, molecular approaches such as ...

Investigación

Inmunología e Infección

Purification of Specific Cell Population by Fluorescence Activated Cell Sorting (FACS)

Experimental and clinical studies often require highly purified cell populations.  FACS is a technique of choice to purify cell populations of known phenotype.  Other bulk methods of purification include panning, complement depletion and magnetic bead separation.  However, FACS has several advantages over other available methods.  FACS is the preferred method when very high purity of the desired population is required, when the target cell population expresses a very low level of the identifying marker or when cell populations require separation based on differential marker density.  In addition, FACS is the only available purification technique to isolate cells based on internal staining or intracellular protein expression, such as a genetically modified fluorescent protein marker.  FACS allows the purification of individual cells based on size, granularity and fluorescence.  In order to purify cells of interest, they are first stained with fluorescently-tagged monoclonal antibodies (mAb), which recognize specific surface markers on the desired cell population (1).  Negative selection of unstained cells is also possible.  FACS purification requires a flow cytometer with sorting capacity and the appropriate software.  For FACS, cells in suspension are passed as a stream in droplets with each containing a single cell in front of a laser.  The fluorescence detection system detects cells of interest based on predetermined fluorescent parameters of the cells.  The instrument applies a charge to the droplet containing a cell of interest and an electrostatic deflection system facilitates collection of the charged droplets into appropriate collection tubes (2).  The success of staining and thereby sorting depends largely on the selection of the identifying markers and the choice of mAb.  Sorting parameters can be adjusted depending on the requirement of purity and yield.  Although FACS requires specialized equipment and personnel training, it is the method of choice for isolation of highly purified cell populations.

Purification of Specific Cell Population by Fluorescence Activated Cell Sorting FACS

For many scientific studies requiring a biological and chemical analysis of cell populations the cells must be in a high state of purity. Fluorescence activated cell sorting (FACS) is a superior method in which to obtain pure cell populations.

La purificación de la población de células específicas de clasificación celular activado por fluorescencia (FACS)

Experimental and clinical studies often require highly purified cell populations.  FACS is a technique of choice to purify cell populations of known ...

Human T Lymphocyte Isolation, Culture and Analysis of Migration In Vitro

The migration of T lymphocytes involves the adhesive interaction of cell surface integrins with ligands expressed on other cells or with extracellular matrix proteins. The precise spatiotemporal activation of integrins from a low affinity state to a high affinity state at the cell leading edge is important for T lymphocyte migration 1. Likewise, retraction of the cell trailing edge, or uropod, is a necessary step in maintaining persistent integrin-dependent T lymphocyte motility 2. Many therapeutic approaches to autoimmune or inflammatory diseases target integrins as a means to inhibit the excessive recruitment and migration of leukocytes 3. To study the molecular events that regulate human T lymphocyte migration, we have utilized an in vitro system to analyze cell migration on a two-dimensional substrate that mimics the environment that a T lymphocyte encounters during recruitment from the vasculature. T lymphocytes are first isolated from human donors and are then stimulated and cultured for seven to ten days. During the assay, T lymphocytes are allowed to adhere and migrate on a substrate coated with intercellular adhesion molecule-1 (ICAM-1), a ligand for integrin LFA-1, and stromal cell-derived factor-1 (SDF-1). Our data show that T lymphocytes exhibit a migratory velocity of ~15 &mu;m/min. T lymphocyte migration can be inhibited by integrin blockade 1 or by inhibitors of the cellular actomyosin machinery that regulates cell migration 2.

Human T Lymphocyte Isolation, Culture and Analysis of Migration In Vitro

T lymphocyte migration occurs during homing to lymphoid organs, exit from the vasculature, and entering into peripheral tissues. Here, we describe a protocol that can be used to analyze T lymphocyte migration in vitro.

Aislamiento de linfocitos T humanos, cultura y análisis de la migración In Vitro</em

The migration of T lymphocytes involves the adhesive interaction of cell surface integrins with ligands expressed on other cells or with extracellular ...

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

Carboxyfluorescein succinimidyl ester (CFSE) is an effective and popular means to monitor lymphocyte division1-3. CFSE covalently labels long-lived intracellular molecules with the fluorescent dye, carboxyfluorescein. Thus, when a CFSE-labeled cell divides, its progeny are endowed with half the number of carboxyfluorescein-tagged molecules and thus each cell division can be assessed by measuring the corresponding decrease in cell fluorescence via Flow cytometry. The capacity of CFSE to label lymphocyte populations with a high fluorescent intensity of exceptionally low variance, coupled with its low cell toxicity, make it an ideal dye to measure cell division. Since it is a fluorescein-based dye it is also compatible with a broad range of other fluorochromes making it applicable to multi-color flow cytometry. This article describes the procedures typically used for labeling mouse lymphocytes for the purpose of monitoring up to 8 cell divisions. These labeled cells can be used both for in vitro and in vivo studies.

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

CFSE covalently labels long-lived intracellular molecules with the fluorescent dye, carboxyfluorescein. As such, when a CFSE-labeled cell divides, its progeny have half the amount of fluorescence, which can thereby be used to assess cell division. This article describes the procedures typically used for labeling mouse lymphocytes with CFSE.

El uso de diacetato de carboxifluoresceína Ester succinimidil (CFSE) para controlar la proliferación de linfocitos

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

Introducing Shear Stress in the Study of Bacterial Adhesion

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

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

La introducción de la tensión de cizallamiento en el Estudio de la adhesión bacteriana

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

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

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

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

Antígenos funcional protegido glóbulos rojos por la membrana injerto de compactos Poligliceroles hiperramificados

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

Methodology for the Efficient Generation of Fluorescently Tagged Vaccinia Virus Proteins

Tagging of viral proteins with fluorescent proteins has proven an indispensable approach to furthering our understanding of virus-host interactions. Vaccinia virus (VACV), the live vaccine used in the eradication of smallpox, is particularly amenable to fluorescent live-cell microscopy owing to its large virion size and the ease with which it can be engineered at the genome level. We report here an optimized protocol for generating recombinant viruses. The minimal requirements for targeted homologous recombination during vaccinia replication were determined, which allows the simplification of construct generation. This enabled the alliance of transient dominant selection (TDS) with a fluorescent reporter and metabolic selection to provide a rapid and modular approach to fluorescently label viral proteins. By streamlining the generation of fluorescent recombinant viruses, we are able to facilitate downstream applications such as advanced imaging analysis of many aspects of the virus-host interplay that occurs during virus replication.

A rapid and modular protocol for the generation of recombinant vaccinia viruses expressing fluorescently&#160;tagged proteins simultaneously using the method of transient dominant selection is described here.

Metodología Para La Generación Eficiente De Proteínas Del Virus Vaccinia Marcadas Fluorescentemente

Tagging of viral proteins with fluorescent  proteins has proven an indispensable approach to furthering our understanding  of virus-host interactions. ...

Assay of Adhesion Under Shear Stress for the Study of T Lymphocyte-Adhesion Molecule Interactions

Overall, T cell adhesion is a critical component of function, contributing to the distinct processes of cellular recruitment to sites of inflammation and interaction with antigen presenting cells (APC) in the formation of immunological synapses. These two contexts of T cell adhesion differ in that T cell-APC interactions can be considered static, while T cell-blood vessel interactions are challenged by the shear stress generated by circulation itself. T cell-APC interactions are classified as static in that the two cellular partners are static relative to each other. Usually, this interaction occurs within the lymph nodes. As a T cell interacts with the blood vessel wall, the cells arrest and must resist the generated shear stress.1,2 These differences highlight the need to better understand static adhesion and adhesion under flow conditions as two distinct regulatory processes. The regulation of T cell adhesion can be most succinctly described as controlling the affinity state of integrin molecules expressed on the cell surface, and thereby regulating the interaction of integrins with the adhesion molecule ligands expressed on the surface of the interacting cell. Our current understanding of the regulation of integrin affinity states comes from often simplistic in vitro model systems. The assay of adhesion using flow conditions described here allows for the visualization and accurate quantification of T cell-epithelial cell interactions in real time following a stimulus. An adhesion under flow assay can be applied to studies of adhesion signaling within T cells following treatment with inhibitory or stimulatory substances. Additionally, this assay can be expanded beyond T cell signaling to any adhesive leukocyte population and any integrin-adhesion molecule pair.

This flow adhesion assay provides a simple, high impact model of T cell-epithelial cell interactions. A syringe pump is used to generate shear stress, and confocal microscopy captures images for quantification. The goal of these studies is to effectively quantify T cell adhesion using flow conditions.

Ensayo de adhesión en condiciones de estrés de cizalla para el Estudio de linfocitos T-molécula de adhesión Interacciones

Overall, T cell adhesion is a critical component of function, contributing to the distinct processes of cellular recruitment to sites of inflammation and ...

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.

Detección de<em&gt; Trypanosoma brucei</em&gt; Variant glicoproteína de superficie de conmutación por Magnetic Activated Cell Sorting y Citometría de Flujo

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

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

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

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

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

El uso de una monocapa de monocitos Ensayo para evaluar la fagocitosis mediada por el receptor Fc gamma

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