Les auteurs tiennent à remercier les conseils techniques de David Briles (Université d&#39;Alabama à Birmingham, AL, USA). Nous tenons à remercier Yvette Chen, le directeur de la protection des animaux de l&#39;Université de Melbourne, et David Taylor, le directeur de l&#39;animalerie, pour des suggestions utiles et des discussions concernant le bien-être animal et éthique et le développement de critères d&#39;intervention et de points d&#39;extrémité humain pour les expériences décrites dans ce manuscrit. Odilia Wijburg et Patrick de lecture sont soutenus par une bourse NHMRC RD Wright, Kirsty court est soutenu par un soutien de GSK Postgraduate de subvention et une bourse Puzey.

<ol>
	<li>Brundage, J. F., Shanks, G. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deaths+from+bacterial+pneumonia+during+1918-19+influenza+pandemic.">Deaths from bacterial pneumonia during 1918-19 influenza pandemic.</a> Emerg Infect Dis. 14, 1193-1199 (2008).</li><li>Petersdorf, R. G., Fusco, J. J., Harter, D. H., Albrink, W. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pulmonary+infections+complicating+Asian+influenza.">Pulmonary infections complicating Asian influenza.</a> AMA Arch Intern Med. 103, 262-272 (1959).</li><li>Diavatopoulos, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influenza+A+virus+facilitates+Streptococcus+pneumoniae+transmission+and+disease.">Influenza A virus facilitates Streptococcus pneumoniae transmission and disease.</a> Faseb J. , (2010).</li><li>Orihuela, C. J., Gao, G., Francis, K. P., Yu, J., Tuomanen, E. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tissue-specific+contributions+of+pneumococcal+virulence+factors+to+pathogenesis.">Tissue-specific contributions of pneumococcal virulence factors to pathogenesis.</a> J Infect Dis. 190, 1661-1669 (2004).</li><li>Kadurugamuwa, 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=Noninvasive+monitoring+of+pneumococcal+meningitis+and+evaluation+of+treatment+efficacy+in+an+experimental+mouse+model.">Noninvasive monitoring of pneumococcal meningitis and evaluation of treatment efficacy in an experimental mouse model.</a> Mol Imaging. 4, 137-142 (2005).</li><li>Smith, M. W., Schmidt, J. E., Rehg, J. E., Orihuela, C. J., McCullers, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Induction+of+pro-+and+anti-inflammatory+molecules+in+a+mouse+model+of+pneumococcal+pneumonia+after+influenza.">Induction of pro- and anti-inflammatory molecules in a mouse model of pneumococcal pneumonia after influenza.</a> Comp Med. 57, 82-89 (2007).</li><li>Owen, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nasal-associated+lymphoid+tissue+and+olfactory+epithelium+as+portals+of+entry+for+Burkholderia+pseudomallei+in+murine+melioidosis.">Nasal-associated lymphoid tissue and olfactory epithelium as portals of entry for Burkholderia pseudomallei in murine melioidosis.</a> J Infect Dis. 199, 1761-1770 (2009).</li><li>Luker, G. D., Leib, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Luciferase+real-time+bioluminescence+imaging+for+the+study+of+viral+pathogenesis.">Luciferase real-time bioluminescence imaging for the study of viral pathogenesis.</a> Methods Mol Biol. 292, 285-296 (2005).</li><li>Hutchens, M., Luker, G. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Applications+of+bioluminescence+imaging+to+the+study+of+infectious+diseases.">Applications of bioluminescence imaging to the study of infectious diseases.</a> Cell Microbiol. 9, 2315-2322 (2007).</li></ol>

La production de cette vidéo a été parrainé par l&#39;article Caliper Life Sciences.

L&#39;imagerie in vivo avec la machine IVIS est une méthodologie unique qui permet la visualisation en temps réel de pathogenèse microbienne 4, 6-9. Ici, nous montrons l&#39;application de cette technologie à la compréhension de la synergie entre S. le virus de la grippe pneumoniae et chez des souris nouveau-né. En raison de la nature non-invasive de cette technique, nous avons été en mesure de surveiller la progression de l&#39;infection dans chaque souris au cours du temps. Cela nous a permis de documenter la cinétique de transmission pneumocoque chez les souriceaux de co-logés 3. La nature non invasive de cette technique permet aux chercheurs d&#39;utiliser moins d&#39;animaux par expérience et donc de réduire l&#39;utilisation des animaux. Il est également possible d&#39;utiliser la machine IVIS pour visualiser la dissémination de l&#39;infection à des sites jusqu&#39;alors inconnue de l&#39;infection dans le corps, ainsi que des sites pas facilement échantillonnées par dissection (tels que l&#39;oreille moyenne). Avant de commencer les expériences d&#39;imagerie, nous avons confirmé que les niveaux de colonisation de la bioluminescence EF3030 souche étaient comparables aux niveaux de colonisation de la société mère EF3030 souche en énumérant comptent viable dans des homogénats de tissu. De plus, nous avons d&#39;abord confirmé que l&#39;infection par le virus de la grippe a entraîné une charge accrue des bioluminescents EF3030 dans le nasopharynx de colonisé animaux comme l&#39;a démontré avec le parent EF3030 souche (résultats non présentés). Bien que la technologie IVIS est facile à utiliser et génère reproductible et facile à comprendre les données, les expériences doivent être soigneusement conçues de telle sorte que la sensibilité et l&#39;utilité de la technologie est maximisée. Par exemple, la sensibilité de la caméra IVIS est affectée par la profondeur et l&#39;opacité du tissu 8, qui dans notre expérience, augmente la limite de détection de signaux bioluminescents provenant des poumons. En outre, la fourrure et la peau pigmentée noire réduit la transmission de lumière par autant que 10 fois (par rapport à des souris sans poils) 8. Tout en développant cette méthode, nous avons optimisé ce protocole pour l&#39;utilisation de 5 à 14 jours C57BL ancien / 6 souris et ont depuis démontré que IVIS peut être utilisé pour détecter la colonisation de la vieille C57BL 20 jours / 6 souris avec S. bioluminescents pneumoniae EF3030. Cependant, la détection du signal peut être augmenté lorsque ces expériences sont réalisées chez la souris nude ou BALB / c. Néanmoins, la caméra IVIS représente une nouvelle approche pour suivre, caractériser et finalement comprendre le développement in vivo de la maladie pneumococcique suivants virus influenza A.

using bioluminescent imaging to investigate synergism between streptococcus pneumoniae and influenza a virus in infant mice

Durant la pandémie de 1918 virus de la grippe, qui a tué environ 50 millions de personnes dans le monde, la majorité des accidents mortels ne sont pas le résultat d&#39;une infection par le virus de la grippe seul. Au lieu de cela, la plupart des individus sont supposés avoir succombé à une infection bactérienne secondaire, principalement causée par la bactérie Streptococcus pneumoniae (le pneumocoque). La relation synergique entre les infections causées par le virus de la grippe et le pneumocoque a été ensuite observée durant la pandémie de grippe 1957 virus asiatique, ainsi que pendant les épidémies saisonnières du virus (revue en 1, 2). Ici, nous décrivons un protocole utilisé pour étudier le mécanisme (s) qui peuvent être impliqués dans la morbidité a augmenté en raison de la grippe Un virus simultanées et S. l&#39;infection pneumoniae. Nous avons développé un modèle murin d&#39;enfant de façon fiable et reproductible de démontrer les effets de l&#39;infection par le virus de la grippe de souris colonisées par S. pneumoniae. En utilisant ce protocole, nous avons fourni un premier aperçu de la cinétique de transmission pneumocoque entre co-logés, en utilisant des souris néonatales imagerie in vivo 3.

Watch this Scientific Journal Video about Using Bioluminescent Imaging to Investigate Synergism Between Streptococcus pneumoniae and Influenza A Virus in Infant Mice at JoVE.com

Using Bioluminescent Imaging to Investigate Synergism Between Streptococcus pneumoniae and Influenza A Virus in Infant Mice

Une infection concomitante par le virus grippal A est l&#39;un des facteurs impliqués dans l&#39;induction de la maladie invasive à pneumocoques pendant asymptomatiques<em&gt; Streptococcus pneumoniae</emChariot&gt;. Nous décrivons ici une méthode d&#39;infection mixte avec des souriceaux d&#39;enquêter sur la synergie entre ces deux agents pathogènes respiratoires.

Utiliser l&#39;imagerie Bioluminescent chargé d&#39;enquêter sur une synergie entre Streptococcus pneumoniae Et virus Influenza A de souriceaux

During the 1918 influenza virus pandemic, which killed approximately 50 million people worldwide, the majority of fatalities were not the result of ...

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Research

JoVE Journal

Immunology and Infection

Using Bioluminescent Imaging to Investigate Synergism Between Streptococcus pneumoniae and Influenza A Virus in Infant Mice

16.7K vues.  University of Melbourne.  中文 

Vidéo: Using Bioluminescent Imaging to Investigate Synergism Between Streptococcus pneumoniae and Influenza A Virus in Infant Mice

Live Cell Imaging of Bacillus subtilis and Streptococcus pneumoniae using Automated Time-lapse Microscopy

During the last few years scientists became increasingly aware that average data obtained from microbial population based experiments are not representative of the behavior, status or phenotype of single cells. Due to this new insight the number of single cell studies rises continuously (for recent reviews see 1,2,3). However, many of the single cell techniques applied do not allow monitoring the development and behavior of one specific single cell in time (e.g. flow cytometry or standard microscopy).
Here, we provide a detailed description of a microscopy method used in several recent studies 4, 5, 6, 7, which allows following and recording (fluorescence of) individual bacterial cells of Bacillus subtilis and Streptococcus pneumoniae through growth and division for many generations. The resulting movies can be used to construct phylogenetic lineage trees by tracing back the history of a single cell within a population that originated from one common ancestor. This time-lapse fluorescence microscopy method cannot only be used to investigate growth, division and differentiation of individual cells, but also to analyze the effect of cell history and ancestry on specific cellular behavior. Furthermore, time-lapse microscopy is ideally suited to examine gene expression dynamics and protein localization during the bacterial cell cycle. The method explains how to prepare the bacterial cells and construct the microscope slide to enable the outgrowth of single cells into a microcolony. In short, single cells are spotted on a semi-solid surface consisting of growth medium supplemented with agarose on which they grow and divide under a fluorescence microscope within a temperature controlled environmental chamber. Images are captured at specific intervals and are later analyzed using the open source software ImageJ.

Live Cell Imaging of Bacillus subtilis and Streptococcus pneumoniae using Automated Time-lapse Microscopy

This protocol provides a step-by-step procedure to monitor single cell behavior of different bacteria in time using automated fluorescence time-lapse microscopy. Furthermore, we provide guidelines how to analyze the microscopy images.

Imagerie de cellules vivantes de la<emBacillus subtilis> Et Streptococcus pneumoniae À l&#39;aide automatisée de microscopie time-lapse

During the last few years scientists became increasingly aware that average data obtained from microbial population based experiments are not ...

Recherche

Immunologie et infection

Bioluminescent Bacterial Imaging In Vivo

This video describes the use of whole body bioluminesce imaging (BLI) for the study of bacterial trafficking in live mice, with an emphasis on the use of bacteria in gene and cell therapy for cancer. Bacteria present an attractive class of vector for cancer therapy, possessing a natural ability to grow preferentially within tumors following systemic administration. Bacteria engineered to express the lux gene cassette permit BLI detection of the bacteria and concurrently tumor sites. The location and levels of bacteria within tumors over time can be readily examined, visualized in two or three dimensions. The method is applicable to a wide range of bacterial species and tumor xenograft types. This article describes the protocol for analysis of bioluminescent bacteria within subcutaneous tumor bearing mice. Visualization of commensal bacteria in the Gastrointestinal tract (GIT) by BLI is also described. This powerful, and cheap, real-time imaging strategy represents an ideal method for the study of bacteria in vivo in the context of cancer research, in particular gene therapy, and infectious disease. This video outlines the procedure for studying lux-tagged E. coli in live mice, demonstrating the spatial and temporal readout achievable utilizing BLI with the IVIS system.

Bioluminescent Bacterial Imaging In Vivo

This article describes the administration of lux-tagged bacteria to mice and subsequent in vivo analysis using IVIS bioluminescence imaging.

Bioluminescent imagerie bactérienne<em&gt; In Vivo</em

This video describes the use of whole body bioluminesce imaging (BLI) for the study of bacterial trafficking in live mice, with an emphasis on the use of ...

Characterization of Inflammatory Responses During Intranasal Colonization with Streptococcus pneumoniae

Nasopharyngeal colonization by Streptococcus pneumoniae is a prerequisite to invasion to the lungs or bloodstream1. This organism is capable of colonizing the mucosal surface of the nasopharynx, where it can reside, multiply and eventually overcome host defences to invade to other tissues of the host. Establishment of an infection in the normally lower respiratory tract results in pneumonia. Alternatively, the bacteria can disseminate into the bloodstream causing bacteraemia, which is associated with high mortality rates2, or else lead directly to the development of pneumococcal meningitis. Understanding the kinetics of, and immune responses to, nasopharyngeal colonization is an important aspect of S. pneumoniae infection models.
Our mouse model of intranasal colonization is adapted from human models3 and has been used by multiple research groups in the study of host-pathogen responses in the nasopharynx4-7. In the first part of the model, we use a clinical isolate of S. pneumoniae to establish a self-limiting bacterial colonization that is similar to carriage events in human adults. The procedure detailed herein involves preparation of a bacterial inoculum, followed by the establishment of a colonization event through delivery of the inoculum via an intranasal route of administration. Resident macrophages are the predominant cell type in the nasopharynx during the steady state. Typically, there are few lymphocytes present in uninfected mice8, however mucosal colonization will lead to low- to high-grade inflammation (depending on the virulence of the bacterial species and strain) that will result in an immune response and the subsequent recruitment of host immune cells. These cells can be isolated by a lavage of the tracheal contents through the nares, and correlated to the density of colonization bacteria to better understand the kinetics of the infection.

Characterization of Inflammatory Responses During Intranasal Colonization with Streptococcus pneumoniae

Colonization of the murine nasopharynx with Streptococcus pneumoniae and the subsequent extraction of adherent or recruited cells is described. This technique involves flushing the nasopharynx and collection of the fluid through the nares and is adaptable for various readouts, including differential cell quantification and analysis of mRNA expression in situ.

Caractérisation des réponses inflammatoires au cours de la colonisation intranasale avec Streptococcus pneumoniae

Nasopharyngeal colonization by Streptococcus pneumoniae is a prerequisite to invasion to the lungs or bloodstream1. This organism is capable of colonizing ...

Monitoring Changes in Membrane Polarity, Membrane Integrity, and Intracellular Ion Concentrations in Streptococcus pneumoniae Using Fluorescent Dyes

Membrane depolarization and ion fluxes are events that have been studied extensively in biological systems due to their ability to profoundly impact cellular functions, including energetics and signal transductions. While both fluorescent and electrophysiological methods, including electrode usage and patch-clamping, have been well developed for measuring these events in eukaryotic cells, methodology for measuring similar events in microorganisms have proven more challenging to develop given their small size in combination with the more complex outer surface of bacteria shielding the membrane. During our studies of death-initiation in Streptococcus pneumoniae (pneumococcus), we wanted to elucidate the role of membrane events, including changes in polarity, integrity, and intracellular ion concentrations. Searching the literature, we found that very few studies exist. Other investigators had monitored radioisotope uptake or equilibrium to measure ion fluxes and membrane potential and a limited number of studies, mostly in Gram-negative organisms, had seen some success using carbocyanine or oxonol fluorescent dyes to measure membrane potential, or loading bacteria with cell-permeant acetoxymethyl (AM) ester versions of ion-sensitive fluorescent indicator dyes. We therefore established and optimized protocols for measuring membrane potential, rupture, and ion-transport in the Gram-positive organism S. pneumoniae. We developed protocols using the bis-oxonol dye DiBAC4(3) and the cell-impermeant dye propidium iodide to measure membrane depolarization and rupture, respectively, as well as methods to optimally load the pneumococci with the AM esters of the ratiometric dyes Fura-2, PBFI, and BCECF to detect changes in intracellular concentrations of Ca2+, K+, and H+, respectively, using a fluorescence-detection plate reader. These protocols are the first of their kind for the pneumococcus and the majority of these dyes have not been used in any other bacterial species. Though our protocols have been optimized for S. pneumoniae, we believe these approaches should form an excellent starting-point for similar studies in other bacterial species.

Monitoring Changes in Membrane Polarity, Membrane Integrity, and Intracellular Ion Concentrations in Streptococcus pneumoniae Using Fluorescent Dyes

Unlike that seen for eukaryotes, there is a paucity of studies that detail membrane depolarization and ion concentration changes in bacteria, primarily as their small size makes conventional methods of measurement difficult. Here, we detail protocols for monitoring such events in the significant Gram-positive pathogen Streptococcus pneumoniae utilizing fluorescence techniques.

La surveillance des changements dans la membrane de polarité, Membrane intégrité, et intracellulaires d&#39;ions concentrations dans<em&gt; Streptococcus pneumoniae</em&gt; Utilisation des colorants fluorescents

Membrane depolarization and ion fluxes are events that have been studied extensively in biological systems due to their ability to profoundly impact ...

Capsular Serotyping of Streptococcus pneumoniae Using the Quellung Reaction

There are over 90 different capsular serotypes of Streptococcus pneumoniae (the pneumococcus). As well as being a tool for understanding pneumococcal epidemiology, capsular serotyping can provide useful information for vaccine efficacy and impact studies.&#160;The Quellung reaction is the gold standard method for pneumococcal capsular serotyping. The method involves testing a pneumococcal cell suspension with pooled and specific antisera directed against the capsular polysaccharide. The antigen-antibody reactions are observed microscopically. The protocol has three main steps: 1) preparation of a bacterial cell suspension, 2) mixing of cells and antisera on a glass slide, and 3) reading the Quellung reaction using a microscope. The Quellung reaction is reasonably simple to perform and can be applied wherever a suitable microscope and antisera are available.

Capsular Serotyping of Streptococcus pneumoniae Using the Quellung Reaction

The Quellung reaction is the gold standard technique for serotyping Streptococcus pneumoniae. This technique utilizes a microscope and specific pneumococcal antisera and is commonly used in reference and research laboratories worldwide.

Capsulaire sérotypage des<em&gt; Streptococcus pneumoniae</em&gt; Utilisation de la réaction Quellung

There are over 90 different capsular serotypes of Streptococcus pneumoniae (the pneumococcus). As well as being a tool for understanding pneumococcal ...

Capsular Serotyping of Streptococcus pneumoniae by Latex Agglutination

Latex agglutination reagents are widely used in microbial diagnosis, identification and serotyping. Streptococcus pneumoniae (the pneumococcus) is a major cause of morbidity and mortality world-wide. Current vaccines target the pneumococcal capsule, and there are over 90 capsular serotypes. Serotyping pneumococcal isolates is therefore important for assessing the impact of vaccination programs and for epidemiological purposes. The World Health Organization has recommended latex agglutination as an alternative method to the &#8216;gold standard&#8217; Quellung test for serotyping pneumococci. Latex agglutination is a relatively simple, quick and inexpensive method; and is therefore suitable for resource-poor settings as well as laboratories with high-volume workloads. Latex agglutination reagents can be prepared in-house utilizing commercially-sourced antibodies that are passively attached to latex particles. This manuscript describes a method of production and quality control of latex agglutination reagents, and details a sequential testing approach which is time- and cost-effective. 
This method of production and quality control may also be suitable for other testing purposes.

Capsular Serotyping of Streptococcus pneumoniae by Latex Agglutination

Latex agglutination testing is a simple, rapid and inexpensive method for serotyping Streptococcus pneumoniae, and has also been widely applied in diagnostic microbiology. This manuscript describes the in-house production of latex agglutination reagents, quality control procedures and the application of this technique to pneumococcal serotyping.

Capsulaire sérotypage<em&gt; Streptococcus pneumoniae</em&gt; Par agglutination au latex

Latex agglutination reagents are widely used in microbial diagnosis, identification and serotyping. Streptococcus pneumoniae (the pneumococcus) is a major ...

Influenza Virus Propagation in Embryonated Chicken Eggs

Influenza infection is associated with about 36,000 deaths and more than 200,000 hospitalizations every year in the United States. The continuous emergence of new influenza virus strains due to mutation and re-assortment complicates the control of the virus and necessitates the permanent development of novel drugs and vaccines. The laboratory-based study of influenza requires a reliable and cost-effective method for the propagation of the virus. Here, a comprehensive protocol is provided for influenza A virus propagation in fertile chicken eggs, which consistently yields high titer viral stocks. In brief, serum pathogen-free (SPF) fertilized chicken eggs are incubated at 37 &#176;C and 55-60% humidity for 10 &#8211; 11 days. Over this period, embryo development can be easily monitored using an egg candler. Virus inoculation is carried out by injection of virus stock into the allantoic cavity using a needle. After 2 days of incubation at 37 &#176;C, the eggs are chilled for at least 4 hr at 4 &#176;C. The eggshell above the air sac and the chorioallantoic membrane are then carefully opened, and the allantoic fluid containing the virus is harvested. The fluid is cleared from debris by centrifugation, aliquoted and transferred to -80 &#176;C for long-term storage. The large amount (5-10 ml of virus-containing fluid per egg) and high virus titer which is usually achieved with this protocol has made the usage of eggs for virus preparation our favorable method, in particular for in vitro studies which require large quantities of virus in which high dosages of the same virus stock are needed.

Fertile chicken eggs are widely used to produce large amounts of human influenza A virus as they provide a convenient and cost-effective system to prove high yields of virus.

Virus de la grippe Propagation dans embryonnés de poulet Oeufs

Influenza infection is associated with about 36,000 deaths and more than 200,000 hospitalizations every year in the United States. The continuous ...

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.

Neutrophiles Isolement et analyse pour déterminer leur rôle dans le lymphome cellulaire Sensibilité aux agents thérapeutiques

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 ...

Influenza A Virus Studies in a Mouse Model of Infection

Influenza viruses cause over 500,000 deaths worldwide1 and are associated with an annual cost of 12 - 14 billion USD in the United States alone considering direct medical and hospitalization expenses and work absenteeism2. Animal models are crucial in Influenza A virus (IAV) studies to evaluate viral pathogenesis, host-pathogen interactions, immune responses, and the efficacy of current and/or novel vaccine approaches as well as antivirals. Mice are an advantageous small animal model because their immune system is evolutionarily similar to that found in humans, they are available from commercial vendors as genetically identical subjects, there are multiple strains that can be exploited to evaluate the genetic basis of infections, and they are relatively inexpensive and easy to manipulate. To recapitulate IAV infection in humans via the airways, mice are first anesthetized prior to intranasal inoculation with infectious IAVs under proper biosafety containment. After infection, the pathogenesis of IAVs is determined by monitoring daily the morbidity (body weight loss) and mortality (survival) rate. In addition, viral pathogenesis can also be evaluated by assessing virus replication in the upper (nasal mucosa) or lower (lungs) respiratory tract of infected mice. Humoral responses upon IAV infection can be rapidly evaluated by non-invasive bleeding and secondary antibody detection assays aimed at detecting the presence of total or neutralizing antibodies. Here, we describe the common methods used to infect mice intranasally (i.n) with IAV and evaluate pathogenesis, humoral immune responses and protection efficacy.

Influenza A viruses (IAVs) are important human respiratory pathogens. To understand the pathogenicity of IAVs and to perform preclinical testing of novel vaccine approaches, animal models mimicking human physiology are required. Here, we describe techniques to evaluate IAV pathogenesis, humoral responses and vaccine efficacy using a mouse model of infection.

Études de Virus influenza de type A dans un modèle murin d’Infection

Influenza viruses cause over 500,000 deaths worldwide1 and are associated with an annual cost of 12 - 14 billion USD in the United States alone ...

Measuring Influenza Neutralizing Antibody Responses to A(H3N2) Viruses in Human Sera by Microneutralization Assays Using MDCK-SIAT1 Cells

Neutralizing antibodies against hemagglutinin (HA) of influenza viruses are considered the main immune mechanism that correlates with protection for influenza infections. Microneutralization (MN) assays are often used to measure neutralizing antibody responses in human sera after influenza vaccination or infection. Madine Darby Canine Kidney (MDCK) cells are the commonly used cell substrate for MN assays. However, currently circulating 3C.2a and 3C.3a A(H3N2) influenza viruses have acquired altered receptor binding specificity. The MDCK-SIAT1 cell line with increased &#945;-2,6 sialic galactose moieties on the surface has proven to provide improved infectivity and more faithful replications than conventional MDCK cells for these contemporary A(H3N2) viruses. Here, we describe a MN assay using MDCK-SIAT1 cells that has been optimized to quantify neutralizing antibody titers to these contemporary A(H3N2) viruses. In this protocol, heat inactivated sera containing neutralizing antibodies are first serially diluted, then incubated with 100 TCID50/well of influenza A(H3N2) viruses to allow antibodies in the sera to bind to the viruses. MDCK-SIAT1 cells are then added to the virus-antibody mixture, and incubated for 18 - 20 h at 37 &#176;C, 5% CO2 to allow A(H3N2) viruses to infect MDCK-SIAT1 cells. After overnight incubation, plates are fixed and the amount of virus in each well is quantified by an enzyme-linked immunosorbent assay (ELISA) using anti-influenza A nucleoprotein (NP) monoclonal antibodies. Neutralizing antibody titer is defined as the reciprocal of the highest serum dilution that provides &#8805;50% inhibition of virus infectivity.

Measuring Influenza Neutralizing Antibody Responses to AH3N2 Viruses in Human Sera by Microneutralization Assays Using MDCK-SIAT1 Cells

Influenza neutralizing antibodies correlate with protection of influenza infections. Microneutralization assays measure neutralizing antibodies in human sera and are often used for influenza human serology. We describe a microneutralization assay using MDCK-SIAT1 cells to measure neutralizing antibody titers to contemporary 3C.2a and 3C.3a A(H3N2) viruses following influenza vaccination or infection.

Grippe neutralisante d’anticorps aux virus a (H3N2) dans le sérum humain par micro-neutralisation de mesure des analyses utilisant des cellules de MDCK-SIAT1

Neutralizing antibodies against hemagglutinin (HA) of influenza viruses are considered the main immune mechanism that correlates with protection for ...