Damos las gracias a Hye Sook-Oh, Morello Joanne y Alan Collmer, Departamento de Patología Vegetal y Biología de las Plantas-Microbios, la Universidad de Cornell, valiosa para los debates. Damos las gracias a Jesse Munkvold comentarios sobre el artículo. El financiamiento fue proporcionado por el Programa Nacional de Ciencia Fundación Genoma Vegetal, el número de premios DBI-0605059 (GBM).

Parte 1: crecimiento de las plantas y el mantenimiento Plantas de Nicotiana benthamiana utilizado en el ensayo debe ser de 7 semanas de edad. Que se debe ajustar por lo menos 4-5 días antes de la prueba para eliminar todas las ramas axilares y flores. Es una buena idea para eliminar ramas axilares poco después de salir a fin de que las plantas sean más manejables. Parte 2: Cultivo bacteriano DIA 1: <ol><li> Placas o las culturas de todas las cepas utilizadas en el ensayo se inició al mismo tiempo. Para las especies de Pseudomonas. que incluyen dos inductores y 3 cepas de desafío, las bacterias en placas KBM racha que contienen los antibióticos apropiados de las existencias de glicerol congelado (Tabla 2). Una pequeña cantidad de bacterias debe ser esparcida en el centro de la placa. Incubar la placa a 30 ° C durante aproximadamente 18-24 horas. De Agrobacterium, iniciar un cultivo líquido en LB 2 ml de un plato fresco y crecer durante la noche a 250 rpm, 30 ° C. </li></ol> DIA 2: <ol start="2"><li> Por Pseudomonas, añadir 150-200 l de KBM líquido a las bacterias y los extendió sobre toda la placa con un esparcidor de vidrio estéril. Ponga la placa posterior en la incubadora y se deja crecer por otro 20-24 horas. Debe haber un césped bacteriano en la placa al día siguiente, lo que indica un buen crecimiento. De Agrobacterium, iniciar un cultivo secundario en alrededor de 50-10 ml de LB con 20 acetosiringona M y se deja crecer durante la noche a 20 horas a 250 rpm, 30 ° C. </li></ol> Parte 3: Plantas de Preparación para el ensayo DIA 2: <ol><li> Un día antes de la prueba de las plantas debe ser trasladado a una habitación a 22-24 ° C, la luz ~ 35-40% de humedad relativa y constante. </li><li> Marcar los círculos en las hojas que son al menos 1,5 cm de diámetro con un marcador negro grueso. De dos a cuatro círculos pueden ser marcados por hoja. Los círculos deben estar bien espaciados y, preferentemente, no cruzar una vena grande. Elegir bien amplió las hojas. Evite las hojas más viejas o las hojas que son difíciles o gruesa al tacto y evitar marcando los círculos en las partes bajas de la hoja. </li></ol> Círculos marcando un día antes de la prueba no es esencial para el protocolo. Sin embargo, se ahorra tiempo si hay un gran número de plantas que están siendo ensayadas, y hace más fácil para lograr una sincronización precisa entre la inducción de la PTI y las inoculaciones desafío. Parte 4: La inducción de la PTI DIA 3: <ol><li> Recoger las células de la placa en 10 mM de MgCl 2 para P. fluorescens y P. putida. De Agrobacterium, se centrifuga la cultura para recoger las células y resuspender en 10 mM de MgCl 2 + 10 mM MES pH 5,6. Repetir la centrifugación y se resuspenden en el MgCl2-MES solución. Medir la densidad óptica (DO) de las células a 600 nm. Ajuste la SAO a los valores finales requeridos como se describe en la Tabla 2. Pseudomonas debe ser finalmente resuspendido en 10 mM MgCl 2 y Agrobacterium en el MgCl2-MES solución. Un volumen total de 25 ml es suficiente para inocular alrededor de 40-50 puntos. </li><li> Infiltrarse en los inductores PTI en los círculos de pre-marcado en las hojas con una jeringa de 1 ml sin aguja. Anote el orden en que las plantas fueron infiltradas y el momento exacto en que la infiltración se inició. </li></ol> Parte 5: Desafío de la inoculación <ol><li> Prepare P. syringae pv. DC3000 tomate, Pst DC3000 hopQ1 Δ-1 y $ pv tabaci. para el desafío, como se describe en el apartado 4.1 y la Tabla 2. </li><li> Siete horas después de la infiltración inductor, realizar la infiltración de desafío en el mismo orden de las plantas como la inducción se llevó a cabo. Por lo general, un punto en la periferia del círculo primera inoculación puede ser utilizado como el centro del círculo de la segunda inoculación. Si hay múltiples puntos en una hoja de continuación, asegúrese de que las infiltraciones no se superpongan. </li><li> Placa de diluciones seriadas de todos los cultivos utilizados para el ensayo en placas KBM o LB con los antibióticos apropiados para determinar el número exacto UFC. </li></ol> Parte 6: Puntaje para la descomposición del PTI Día 5: <ol><li> Busque la aparición de la muerte celular debido a la ETI en los lugares que fueron inoculados con Pst DC3000. La muerte celular en el interior del área de solapamiento de la infiltración indica el desglose de PTI y debe ser calificado como un fenotipo positivo. </li></ol> Día 7: <ol start="2"><li> Busque la aparición de la muerte celular debido a la enfermedad en los lugares que fueron inoculados con Pst DC3000 hopQ1 Δ-1 o pv Ps. Tabaci </em&gt;. Puntuación de un fenotipo positivo de la misma manera como se describe en la parte 6.1. </li></ol> Cuando las plantas de control (que no debe verse comprometida por PTI) comienzan a mostrar la muerte celular en la zona de solapamiento de la infiltración, dejar de hacer nuevas observaciones. Parte 7: Los resultados representativos La figura 1 muestra el resultado de un ensayo cuando P. fluorescens fue utilizado como el inductor y Pst DC3000 como el desafío. <img src="/files/ftp_upload/1442/fig1tmb.jpg" alt="Figura 1" border="0" /> Figura 1. P. fluorescens fue infiltrado en N. benthamiana hojas (círculo negro) para inducir la PTI y 7 horas más tarde, el acto fue impugnado con Pst DC3000 (círculo blanco). Plantas silenciadas por FLS2 mostró un desglose de PTI en la región donde P. fluorescens fue infiltrado (A), como se ve por la muerte celular. Las plantas de control que no fueron silenciados no mostró la muerte celular en la zona de solapamiento debido a la inducción de la PTI (B). Las flechas rojas indican la falta de presencia o de la muerte celular en el área de superposición de la infiltración. Las fotografías fueron tomadas dos días después de la infiltración. Por favor, <a href="https://www.jove.com/files/ftp_upload/1442/fig1.jpg">haga clic aquí</a> para ver una versión ampliada de la figura 1. <table border="1"><tbody><tr><td> PTI inductor </td><td> Provocando la muerte celular-desafío </td><td> La naturaleza de la muerte celular </td><td> Código </td></tr><tr><td> Pseudomonas fluorescens 55 </td><td> Pseudomonas syringae pv tomate (Pst). DC3000 6 </td><td> ETI </td><td> Pf / DC </td></tr><tr><td> P. putida KT2440 </td><td> Pst DC3000 </td><td> ETI </td><td> Pp / DC </td></tr><tr><td> P. fluorescens 55 </td><td> Pst DC3000 hopQ1 Δ-1 6 </td><td> Enfermedad </td><td> Pf/Q1-1 </td></tr><tr><td> Agrobacterium tumefaciens GV2260 </td><td> P. syringae pv. tabaci 11528R </td><td> Enfermedad </td><td> Agro / PTab </td></tr></tbody></table> Tabla 1: Combinaciones de inducir la muerte celular PTI y que suscitan los microbios utilizados en el ensayo de la muerte celular por PTI. <table border="1"><tbody><tr><td> Cepa bacteriana </td><td> Selección del medio </td><td> OD final utilizada en el experimento </td><td> Correspondiente UFC / ml </td></tr><tr><td> P. fluorescens 55 </td><td> KBM ampicilina (100 ug / ml) </td><td> 0.5 </td><td> 1 x 10 9 </td></tr><tr><td> P. putida KT2440 </td><td> KBM ampicilina (100 ug / ml) </td><td> 0.5 </td><td> 1 x 10 8 </td></tr><tr><td> A. tumefaciens GV2260 </td><td> LB con rifampicina (100 ug / ml) </td><td> 0.5 </td><td> 5 x 10 8 </td></tr><tr><td> Pst DC3000 </td><td> KBM rifampicina (100 ug / ml) </td><td> 0.02 </td><td> 2 x 10 7 </td></tr><tr><td> Pst DC3000 hopQ1 Δ-1 </td><td> KBM rifampicina (100 ug / ml) </td><td> 100 veces la dilución de 0,1 </td><td> 1 x 10 6 </td></tr><tr><td> P. syringae pv. tabaci 11528R </td><td> KBM rifampicina (100 ug / ml) </td><td> 100 veces la dilución de 0,1 </td><td> 1 x 10 6 </td></tr></tbody></table> Tabla 2: Las condiciones de cultivo y los niveles de inóculo utilizado en el ensayo. El OD y los correspondientes niveles UFC pueden variar entre diferentes marcas de espectrofotómetros.

<ol>
	<li>Abramovitch, R. B., Anderson, J. C., Martin, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bacterial+elicitation+and+evasion+of+plant+innate+immunity.">Bacterial elicitation and evasion of plant innate immunity.</a> Nat Rev Mol Cell Biol. 7 (8), 601-60 (2006).</li><li>Jones, J. D., Dangl, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+plant+immune+system.">The plant immune system.</a> Nature. 444 (7117), 323-323 (2006).</li><li>Zipfel, C., Robatzek, S., Navarro, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bacterial+disease+resistance+in+Arabidopsis+through+flagellin+perception.">Bacterial disease resistance in Arabidopsis through flagellin perception.</a> Nature. 428 (6984), 764-764 (2004).</li><li>Oh, H. S., Collmer, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Basal+resistance+against+bacteria+in+Nicotiana+benthamiana+leaves+is+accompanied+by+reduced+vascular+staining+and+suppressed+by+multiple+Pseudomonas+syringae+type+III+secretion+system+effector+proteins.">Basal resistance against bacteria in Nicotiana benthamiana leaves is accompanied by reduced vascular staining and suppressed by multiple Pseudomonas syringae type III secretion system effector proteins.</a> Plant J. 44 (2), 348-348 (2005).</li><li>Goodin, M. M., Zaitlin, D., Naidu, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nicotiana+benthamiana:+its+history+and+future+as+a+model+for+plant-pathogen+interactions.">Nicotiana benthamiana: its history and future as a model for plant-pathogen interactions.</a> Mol Plant Microbe Interact. 21 (8), 1015-1015 (2008).</li><li>Wei, C. F., Kvitko, B. H., Shimizu, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Pseudomonas+syringae+pv.+tomato+DC3000+mutant+lacking+the+type+III+effector+HopQ1-1+is+able+to+cause+disease+in+the+model+plant+Nicotiana+benthamiana.">A Pseudomonas syringae pv. tomato DC3000 mutant lacking the type III effector HopQ1-1 is able to cause disease in the model plant Nicotiana benthamiana.</a> Plant J. 51 (1), 32-32 (2007).</li></ol>

Ensayo de la muerte de la célula-basado puede ser utilizada para determinar la participación de un gen en el PTI. Por ejemplo, la pérdida de función de mutantes de un gen de interés se puede probar mediante este ensayo. De las cuatro combinaciones de inductor e inoculaciones desafío en la Tabla 1, es posible que sólo una combinación puede resultar en un fenotipo en el fondo de la planta. Hemos observado que las plantas silenciadas por FLS2 muestran un desglose del PTI en el Pf / DC y Pf/Q1-1 combinaciones de inductor e inoculaciones desafío (Tabla 1). Es esencial que las condiciones ambientales para el ensayo son lo más cercano posible a los descritos en la parte 3.1. La baja humedad provoca la muerte celular de proceder con demasiada rapidez, haciendo que el ensayo de difícil calificación. Si las condiciones descritas en el protocolo de no trabajar en su laboratorio, y luego tratar de alterar el nivel de inductor o inoculación de desafío. Otro parámetro que se puede modificar es el intervalo de tiempo entre la inducción y la provocación, aunque se ha encontrado que más cortos intervalos de tiempo causó que el ensayo se descomponen muy rápidamente en las plantas de control. Le recomendamos que por lo menos 4-5 plantas a prueba en un experimento y un fenotipo positivo se debe repetir por lo menos en experimentos independientes 3-4.

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assay for pathogen-associated molecular pattern (pamp)-triggered immunity (pti) in plants

Para percibir los patógenos potenciales en su entorno, las plantas utilizan receptores de reconocimiento de patrones (RRP) presentes en su membrana plasmática. PRR reconoce conserva las características microbianas llamado patógeno patrones moleculares asociados (PAMP) y esto lleva a la detección de PAMP disparado por la inmunidad (PTI), lo que efectivamente previene la colonización de los tejidos de la planta por no patógenos 1,2. El sistema más estudiado bien en PTI es la vía 3 FLS2-dependiente. FLS2 reconoce la flg22 PAMP que es un componente de la flagelina bacteriana. Patógenos éxito poseen factores de virulencia o efectores que pueden suprimir la PTI y permitir que el patógeno que causa la enfermedad 1. Algunas plantas, a su vez poseen los genes de resistencia que detectan los efectores o su actividad, lo que lleva a efectores activados por la inmunidad (ETI) 2. Se describe una celda de la muerte de ensayo basado en la PTI modificado a partir de Oh y Collmer 4. El ensayo fue estandarizado en el N. benthamiana, que se está utilizando cada vez más como un sistema modelo para el estudio de las interacciones planta-patógeno 5. PTI es inducida por la infiltración de una cepa no patógena de bacterias en las hojas. Siete horas después, una cepa bacteriana que causa la enfermedad o bien que se activa la ETI se infiltra en una zona de solapamiento de la zona de infiltración original. PTI inducida por la primera infiltración es capaz de retrasar o prevenir la aparición de la muerte celular debido a la infiltración segundo desafío. Por el contrario, la aparición de la muerte celular en la zona de solapamiento de la inoculación indica el desglose de PTI. Cuatro combinaciones diferentes de los inductores del PTI y las inoculaciones desafío fueron estandarizadas (Tabla 1). El ensayo fue probado en no callar N. benthamiana plantas que sirvieron de control y las plantas de silencio para FLS2 que se prevé que se compromete en su capacidad de desarrollar PTI.

Watch this Scientific Journal Video about Assay for Pathogen-Associated Molecular Pattern PAMP-Triggered Immunity PTI in Plants at JoVE.com

Assay for Pathogen-Associated Molecular Pattern PAMP-Triggered Immunity PTI in Plants

Una célula de la muerte de ensayo basado en la PTI en plantas de Nicotiana benthamiana se describe.

Ensayo para asociados a patógenos patrón molecular (PAMP)-Accionados Inmunidad (PTI) en las plantas

To perceive potential pathogens in their environment, plants use pattern recognition receptors (PRRs) present on their plasma membranes. PRRs recognize ...

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Research

JoVE Journal

Immunology and Infection

Assay for Pathogen-Associated Molecular Pattern (PAMP)-Triggered Immunity (PTI) in Plants

27.0K vistas.  Boyce Thompson Institute for Plant Research. Una célula de la muerte de ensayo basado en la PTI en plantas de Nicotiana benthamiana se describe.

Video: Assay for Pathogen-Associated Molecular Pattern PAMP-Triggered Immunity PTI in Plants

Selection of Plasmodium falciparum Parasites for Cytoadhesion to Human Brain Endothelial Cells

Most human malaria deaths are caused by blood-stage Plasmodium falciparum parasites. Cerebral malaria, the most life-threatening complication of the disease, is characterised by an accumulation of Plasmodium falciparum infected red blood cells (iRBC) at pigmented trophozoite stage in the microvasculature of the brain2-4. This microvessel obstruction (sequestration) leads to acidosis, hypoxia and harmful inflammatory cytokines (reviewed in 5). Sequestration is also found in most microvascular tissues of the human body2, 3. The mechanism by which iRBC attach to the blood vessel walls is still poorly understood.
The immortalized Human Brain microvascular Endothelial Cell line (HBEC-5i) has been used as an in vitro model of the blood-brain barrier6. However, Plasmodium falciparum iRBC attach only poorly to HBEC-5i in vitro, unlike the dense sequestration that occurs in cerebral malaria cases. We therefore developed a panning assay to select (enrich) various P. falciparum strains for adhesion to HBEC-5i in order to obtain populations of high-binding parasites, more representative of what occurs in vivo.
A sample of a parasite culture (mixture of iRBC and uninfected RBC) at the pigmented trophozoite stage is washed and incubated on a layer of HBEC-5i grown on a Petri dish. After incubation, the dish is gently washed free from uRBC and unbound iRBC. Fresh uRBC are added to the few iRBC attached to HBEC-5i and incubated overnight. As schizont stage parasites burst, merozoites reinvade RBC and these ring stage parasites are harvested the following day. Parasites are cultured until enough material is obtained (typically 2 to 4 weeks) and a new round of selection can be performed. Depending on the P. falciparum strain, 4 to 7 rounds of selection are needed in order to get a population where most parasites bind to HBEC-5i. The binding phenotype is progressively lost after a few weeks, indicating a switch in variant surface antigen gene expression, thus regular selection on HBEC-5i is required to maintain the phenotype.
In summary, we developed a selection assay rendering P. falciparum parasites a more "cerebral malaria adhesive" phenotype. We were able to select 3 out of 4 P. falciparum strains on HBEC-5i. This assay has also successfully been used to select parasites for binding to human dermal and pulmonary endothelial cells. Importantly, this method can be used to select tissue-specific parasite populations in order to identify candidate parasite ligands for binding to brain endothelium. Moreover, this assay can be used to screen for putative anti-sequestration drugs7.

Selection of Plasmodium falciparum Parasites for Cytoadhesion to Human Brain Endothelial Cells

An in vitro model for cerebral malaria sequestration is described1. Plasmodium falciparum infected red blood cells are selected for binding to immortalized human brain microvascular endothelial cells. The selected parasites show a distinct phenotype. The selection process can be applied using various P. falciparum strains and endothelial cell lines.

Selección de Plasmodium falciparum Los parásitos de cytoadhesion a las células cerebrales endoteliales humanas

Most human malaria deaths are caused by blood-stage Plasmodium falciparum parasites. Cerebral malaria, the most life-threatening complication of the ...

Investigación

Inmunología e Infección

Investigating the Effects of Probiotics on Pneumococcal Colonization Using an In Vitro Adherence Assay

Adherence of Streptococcus pneumoniae (the pneumococcus) to the epithelial lining of the nasopharynx can result in colonization and is considered a prerequisite for pneumococcal infections such as pneumonia and otitis media. In vitro adherence assays can be used to study the attachment of pneumococci to epithelial cell monolayers and to investigate potential interventions, such as the use of probiotics, to inhibit pneumococcal&#160;colonization.&#160;The protocol described here is used to investigate the effects of the probiotic Streptococcus salivarius on the adherence of pneumococci to the human epithelial cell line CCL-23 (sometimes referred to as HEp-2 cells). The assay involves three main steps: 1) preparation of epithelial and bacterial cells, 2) addition of bacteria to epithelial cell monolayers, and 3) detection of adherent pneumococci by viable counts (serial dilution and plating) or quantitative real-time PCR (qPCR). This technique is relatively straightforward and does not require specialized equipment other than a tissue culture setup. The assay can be used to test other probiotic species and/or potential inhibitors of pneumococcal colonization and can be easily modified to address other scientific questions regarding pneumococcal adherence and invasion.

Investigating the Effects of Probiotics on Pneumococcal Colonization Using an In Vitro Adherence Assay

In vitro adherence assays can be used to study the attachment of Streptococcus pneumoniae to epithelial cell monolayers and to investigate potential interventions such as the use of probiotics for inhibiting pneumococcal colonization.

La investigación de los efectos de los probióticos en antineumocócica Colonización El uso de un<em&gt; In Vitro</em&gt; Ensayo de adherencia

Adherence of Streptococcus pneumoniae (the pneumococcus) to the epithelial lining of the nasopharynx can result in colonization and is considered a ...

A Flow Adhesion Assay to Study Leucocyte Recruitment to Human Hepatic Sinusoidal Endothelium Under Conditions of Shear Stress

Leucocyte infiltration into human liver tissue is a common process in all adult inflammatory liver diseases. Chronic infiltration can drive the development of fibrosis and progression to cirrhosis. Understanding the molecular mechanisms that mediate leucocyte recruitment to the liver could identify important therapeutic targets for liver disease. The key interaction during leucocyte recruitment is that of inflammatory cells with endothelium under conditions of shear stress. Recruitment to the liver occurs within the low shear channels of the hepatic sinusoids which are lined by hepatic sinusoidal endothelial cells (HSEC). The conditions within the hepatic sinusoids can be recapitulated by perfusing leucocytes through channels lined by human HSEC monolayers at specific flow rates. In these conditions leucocytes undergo a brief tethering step followed by activation and firm adhesion, followed by a crawling step and subsequent transmigration across the endothelial layer. Using phase contrast microscopy, each step of this &#39;adhesion cascade&#39; can be visualized and recorded followed by offline analysis. Endothelial cells or leucocytes can be pretreated with inhibitors to determine the role of specific molecules during this process.

Leucocyte recruitment to the liver occurs within the specialized channels of the hepatic sinusoids which are lined by unique hepatic sinusoidal endothelial cells. Phase contrast microscopy of leucocyte recruitment across human hepatic sinusoidal endothelium under conditions of physiological shear stress can facilitate the elucidation of the molecular mechanisms which underlie this process.

Un ensayo de adhesión de flujo para estudiar Leucocyte Reclutamiento para hepático humano sinusoidales endotelio en condiciones de estrés de cizalla

Leucocyte infiltration into human liver tissue is a common process in all adult inflammatory liver diseases. Chronic infiltration can drive the ...

High Yield Purification of Plasmodium falciparum Merozoites For Use in Opsonizing Antibody Assays

Plasmodium falciparum merozoite antigens are under development as potential malaria vaccines. One aspect of immunity against malaria is the removal of free merozoites from the blood by phagocytic cells. However assessing the functional efficacy of merozoite specific opsonizing antibodies is challenging due to the short half-life of merozoites and the variability of primary phagocytic cells. Described in detail herein is a method for generating viable merozoites using the E64 protease inhibitor, and an assay of merozoite opsonin-dependent phagocytosis using the pro-monocytic cell line THP-1. E64 prevents schizont rupture while allowing the development of merozoites which are released by filtration of treated schizonts. &#160;Ethidium bromide labelled merozoites are opsonized with human plasma samples and added to THP-1 cells. Phagocytosis is assessed by a standardized high throughput protocol. Viable merozoites are a valuable resource for assessing numerous aspects of P. falciparum biology, including assessment of immune function. Antibody levels measured by this assay are associated with clinical immunity to malaria in naturally exposed individuals. The assay may also be of use for assessing vaccine induced antibodies. &#160;

High Yield Purification of Plasmodium falciparum Merozoites For Use in Opsonizing Antibody Assays

Measuring antibody function is key to understanding immunity to Plasmodium falciparum malaria. This method describes the purification of viable merozoites, and measurement of opsonization-dependent phagocytosis by flow cytometry.

Alto Rendimiento Purificación de<em&gt; Plasmodium falciparum</em&gt; Los merozoitos Para uso en opsonizante Antibody Ensayos

Plasmodium falciparum merozoite antigens are under development as potential malaria vaccines. One aspect of immunity against malaria is the removal of ...

Neutrophil Isolation and Analysis to Determine their Role in Lymphoma Cell Sensitivity to Therapeutic Agents

Neutrophils are the most abundant (40% to 75%) type of white blood cells and among the first inflammatory cells to migrate towards the site of inflammation. They are key players in the innate immune system and play major roles in cancer biology. Neutrophils have been proposed as key mediators of malignant transformation, tumor progression, angiogenesis and in the modulation of the antitumor immunity; through their release of soluble factors or their interaction with tumor cells. To characterize the specific functions of neutrophils, a fast and reliable method is coveted for in vitro isolation of neutrophils from human blood. Here, a density gradient separation method is demonstrated to isolate neutrophils as well as mononuclear cells from the blood. The procedure consists of layering the density gradient solution such as Ficoll carefully above the diluted blood obtained from patients diagnosed with chronic lymphocytic leukemia (CLL), followed by centrifugation, isolation of mononuclear layer, separation of neutrophils from RBCsby dextran then lysis of residual erythrocytes. This method has been shown to isolate neutrophils &#8805; 90 % pure. To mimic the tumor microenvironment, 3-dimensional (3D) experiments were performed using basement membrane matrix such as Matrigel. Given the short half-life of neutrophils in vitro, 3D experiments with fresh human neutrophils cannot be performed. For this reason promyelocytic HL60 cells are differentiated along the granulocytic pathway using the differentiation inducers dimethyl sulfoxide (DMSO) and retinoic acid (RA). The aim of our experiments is to study the role of neutrophils on the sensitivity of lymphoma cells to anti-lymphoma agents. However these methods can be generalized to study the interactions of neutrophils or neutrophil-like cells with a large range of cell types in different situations.

Neutrophils are the most abundant type of white blood cells. The isolation of neutrophils from human blood by density gradient separation method and the differentiation of human promyelocytic (HL60) cells along the granulocytic pathway are described here; to test their role on sensitivity of lymphoma cells to anti-lymphoma agents.

Aislamiento de neutrófilos y análisis para determinar su papel en el linfoma de células sensibles a los agentes terapéuticos

Neutrophils are the most abundant (40% to 75%) type of white blood cells and among the first inflammatory cells to migrate towards the site of ...

Fluorescence-based Neuraminidase Inhibition Assay to Assess the Susceptibility of Influenza Viruses to The Neuraminidase Inhibitor Class of Antivirals

The neuraminidase (NA) inhibitors are the only class of antivirals approved for the treatment and prophylaxis of influenza that are effective against currently circulating strains. In addition to their use in treating seasonal influenza, the NA inhibitors have been stockpiled by a number of countries for use in the event of a pandemic. It is therefore important to monitor the susceptibility of circulating influenza viruses to this class of antivirals. There are different types of assays that can be used to assess the susceptibility of influenza viruses to the NA inhibitors, but the enzyme inhibition assays using either a fluorescent substrate or a chemiluminescent substrate are the most widely used and recommended. This protocol describes the use of a fluorescence-based assay to assess influenza virus susceptibility to NA inhibitors. The assay is based on the NA enzyme cleaving the 2&#8242;-(4-Methylumbelliferyl)-&#945;-D-N-acetylneuraminic acid (MUNANA) substrate to release the fluorescent product 4-methylumbelliferone (4-MU). Therefore, the inhibitory effect of an NA inhibitor on the influenza virus NA is determined based on the concentration of the NA inhibitor that is required to reduce 50% of the NA activity, given as an IC50 value.

We describe the use of a phenotypic fluorescence-based neuraminidase inhibition assay to assess the susceptibility of influenza A and B viruses to the neuraminidase inhibitor class of antivirals.

La neuraminidasa Ensayo de inhibición basado en la fluorescencia para evaluar la susceptibilidad de los virus de la influenza a El Inhibidor de la neuraminidasa clase de antivirales

The neuraminidase (NA) inhibitors are the only class of antivirals approved for the treatment and prophylaxis of influenza that are effective against ...

Mouse Models Of Helicobacter Infection And Gastric Pathologies

Helicobacter pylori is a gastric pathogen that is present in half of the global population and is a significant cause of morbidity and mortality in humans. Several mouse models of gastric Helicobacter infection have been developed to study the molecular and cellular mechanisms whereby H. pylori bacteria colonize the stomach of human hosts and cause disease. Herein, we describe protocols to: 1) prepare bacterial suspensions for the in vivo infection of mice via intragastric gavage; 2) determine bacterial colonization levels in mouse gastric tissues, by polymerase chain reaction (PCR) and viable counting; and 3) assess pathological changes, by histology. To establish Helicobacter infection in mice, specific pathogen-free (SPF) animals are first inoculated with suspensions (containing &#8805;105 colony-forming units, CFUs) of mouse-colonizing strains of either Helicobacter pylori or other gastric Helicobacter spp. from animals, such as Helicobacter felis. At the appropriate time-points post-infection, stomachs are excised and dissected sagittally into two equal tissue fragments, each comprising the antrum and body regions. One of these fragments is then used for either viable counting or DNA extraction, while the other is subjected to histological processing. Bacterial colonization and histopathological changes in the stomach may be assessed routinely in gastric tissue sections stained with Warthin-Starry, Giemsa or Haematoxylin and Eosin (H&#38;E) stains, as appropriate. Additional immunological analyses may also be undertaken by immunohistochemistry or immunofluorescence on mouse gastric tissue sections. The protocols described below are specifically designed to enable the assessment in mice of gastric pathologies resembling those in human-related H. pylori diseases, including inflammation, gland atrophy and lymphoid follicle formation. The inoculum preparation and intragastric gavage protocols may also be adapted to study the pathogenesis of other enteric human pathogens that colonize mice, such as Salmonella Typhimurium or Citrobacter rodentium.

Mouse Models Of Helicobacter Infection And Gastric Pathologies

Mice represent an invaluable in vivo model to study infection and diseases caused by gastrointestinal microorganisms. Here, we describe the methods used to study bacterial colonization and histopathological changes in mouse models of Helicobacter pylori-related disease.

Modelos de ratón de la infección por Helicobacter y patologías gástricas

Helicobacter pylori is a gastric pathogen that is present in half of the global population and is a significant cause of morbidity and mortality in ...

Establishment of Viral Infection and Analysis of Host-Virus Interaction in Drosophila Melanogaster

Virus spreading is a major cause of epidemic diseases. Thus, understanding the interaction between the virus and the host is very important to extend our knowledge of prevention and treatment of viral infection. The fruit fly Drosophila melanogaster has proven to be one of the most efficient and productive model organisms to screen for antiviral factors and investigate virus-host interaction, due to powerful genetic tools and highly conserved innate immune signaling pathways. The procedure described here demonstrates a nano-injection method to establish viral infection and induce systemic antiviral responses in adult flies. The precise control of the viral injection dose in this method enables high experimental reproducibility. Protocols described in this study include the preparation of flies and the virus, the injection method, survival rate analysis, the virus load measurement, and an antiviral pathway assessment. The influence effects of viral infection by the flies' background were mentioned here. This infection method is easy to perform and quantitatively repeatable; it can be applied to screen for host/viral factors involved in virus-host interaction and to dissect the crosstalk between innate immune signaling and other biological pathways in response to viral infection.

Establishment of Viral Infection and Analysis of Host-Virus Interaction in Drosophila Melanogaster

This protocol describes how to establish viral infection in vivo in Drosophila melanogaster using the nano-injection method and basic techniques to analyze virus-host interaction.

Establecimiento de la infección Viral y análisis de la interacción huésped-Virus en Drosophila Melanogaster

Virus spreading is a major cause of epidemic diseases. Thus, understanding the interaction between the virus and the host is very important to extend our ...

Confocal Imaging of Double-Stranded RNA and Pattern Recognition Receptors in Negative-Sense RNA Virus Infection

Double-stranded (ds) RNA is produced as a replicative intermediate during RNA virus infection. Recognition of dsRNA by host pattern recognition receptors (PRRs) such as the retinoic acid (RIG-I) like receptors (RLRs) RIG-I and melanoma differentiation-associated protein 5 (MDA-5) leads to the induction of the innate immune response. The formation and intracellular distribution of dsRNA in positive-sense RNA virus infection has been well characterized by microscopy. Many negative-sense RNA viruses, including some arenaviruses, trigger the innate immune response during infection. However, negative-sense RNA viruses were thought to produce low levels of dsRNA, which hinders the imaging study of PRR recognition of viral dsRNA. Additionally, infection experiments with highly pathogenic arenaviruses must be performed in high containment biosafety level facilities (BSL-4). The interaction between viral RNA and PRRs for highly pathogenic RNA virus is largely unknown due to the additional technical challenges that researchers need to face in the BSL-4 facilities. Recently, a monoclonal antibody (Mab) (clone 9D5) originally used for pan-enterovirus detection has been found to specifically detect dsRNA with a higher sensitivity than the traditional J2 or K1 anti-dsRNA antibodies. Herein, by utilizing the 9D5 antibody, we describe a confocal microscopy protocol that has been used successfully to visualize dsRNA, viral protein and PRR simultaneously in individual cells infected by arenavirus. The protocol is also suitable for imaging studies of dsRNA and PRR distribution in pathogenic arenavirus infected cells in BSL4 facilities.

Double-stranded RNA produced during RNA virus replication can be recognized by pattern recognition receptors to induce an innate immune response. For negative-sense RNA viruses, the interaction between the low-level dsRNA and PRRs remains unclear. We have developed a confocal microscopy method to visualize arenavirus dsRNA and PRR in individual cells.

Proyección de imagen confocal de ARN bicatenario y receptores de reconocimiento de patrón en la infección por Virus de ARN de sentido negativo

Double-stranded (ds) RNA is produced as a replicative intermediate during RNA virus infection. Recognition of dsRNA by host pattern recognition receptors ...

Intravital Imaging of Intraepithelial Lymphocytes in Murine Small Intestine

Intraepithelial lymphocytes expressing &#947;&#948; T cell receptor (&#947;&#948; IEL) play a key role in immune surveillance of the intestinal epithelium. Due in part to the lack of a definitive ligand for the &#947;&#948; T cell receptor, our understanding of the regulation of &#947;&#948; IEL activation and their function in vivo remains limited. This necessitates the development of alternative strategies to interrogate signaling pathways involved in regulating &#947;&#948; IEL function and the responsiveness of these cells to the local microenvironment. Although &#947;&#948; IELs are widely understood to limit pathogen translocation, the use of intravital imaging has been critical to understanding the spatiotemporal dynamics of IEL/epithelial interactions at steady-state and in response to invasive pathogens. Herein, we present a protocol for visualizing IEL migratory behavior in the small intestinal mucosa of a GFP &#947;&#948; T cell reporter mouse using inverted spinning disk confocal laser microscopy. Although the maximum imaging depth of this approach is limited relative to the use of two-photon laser-scanning microscopy, spinning disk confocal laser microscopy provides the advantage of high speed image acquisition with reduced photobleaching and photodamage. Using 4D image analysis software, T cell surveillance behavior and their interactions with neighboring cells can be analyzed following experimental manipulation to provide additional insight into IEL activation and function within the intestinal mucosa.

We describe a method to visualize GFP-labeled &#947;&#948; IELs using intravital imaging of murine small intestine by inverted spinning disk confocal microscopy. This technique enables the tracking of live cells within the mucosa for up to 4 h and can be used to investigate a variety of intestinal immune-epithelial interactions. &#160;