Los autores desean agradecer a la asesoría técnica de David Briles (Universidad de Alabama en Birmingham, AL, EE.UU.). Nos gustaría dar las gracias a Yvette Chen, el encargado del bienestar animal de la Universidad de Melbourne, y David Taylor, el Gerente del establecimiento de animales, por sus útiles sugerencias y discusiones sobre el bienestar animal y la ética y el desarrollo de criterios de intervención y los puntos finales humana para los experimentos descritos en este manuscrito. Odilia Wijburg y lectura Patrick son apoyados por un NHMRC RD Wright Fellowship, Kirsty corto es apoyado por un soporte GSK Postgrado de subvención y una beca 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 producción de este video-artículo fue patrocinado por Caliper Life Sciences.

Imágenes in vivo con la máquina de IVIS es una metodología única que permite la visualización en tiempo real de patogénesis microbiana 4, 6-9. Aquí, se muestra la aplicación de esta tecnología a la comprensión de la sinergia entre S. pneumoniae y el virus de la gripe en ratones lactantes. Debido a la naturaleza no invasiva de esta técnica, hemos sido capaces de controlar la progresión de la infección en cada ratón individual a través del tiempo. Esto nos ha permitido documentar la cinética de la transmisión del neumococo entre los ratones jóvenes co-alojados 3. La naturaleza no invasiva de esta técnica permite a los investigadores a utilizar menos animales por experimentar y por lo tanto, reducir el uso de animales. También es posible utilizar la máquina de IVIS para visualizar la diseminación de la infección a sitios desconocidos de la infección en el cuerpo, así como los sitios de muestreo no es fácil por la disección (por ejemplo, el oído medio). Antes de comenzar los experimentos de imagen, se confirmó que los niveles de colonización de la cepa bioluminiscente EF3030 fueron comparables a los niveles de colonización de los padres EF3030 cepa mediante la enumeración de cuenta viable en homogeneizados de tejido. Además, se confirmó por primera vez que la infección con el virus de la influenza resultó en aumento de la carga de bioluminiscentes EF3030 en la nasofaringe de los animales colonizaron como se demuestra con el padre cepa EF3030 (resultados no mostrados). Si bien la tecnología IVIS es fácil de operar y genera reproducible y fácil de entender los datos, los experimentos deben ser diseñados cuidadosamente para que la sensibilidad y la utilidad de la tecnología se maximiza. Por ejemplo, la sensibilidad de la cámara IVIS se ve afectada por la profundidad y la opacidad de los tejidos 8, que en nuestra experiencia, aumenta el límite de detección de señales bioluminiscentes procedente de los pulmones. Además, el pelo oscuro y piel pigmentada reduce la transmisión de la luz hasta en 10 veces (en comparación con los ratones sin pelo) 8. Durante el desarrollo de este método, hemos optimizado el protocolo para su uso con C57BL días 5 a 14 años / 6 ratones y desde entonces han demostrado que IVIS se puede utilizar para detectar la colonización de los 20 días de edad C57BL / 6 ratones con bioluminiscentes S. pneumoniae EF3030. Sin embargo, la detección de la señal puede ser mayor cuando estos experimentos se llevan a cabo en ratones desnudos o BALB / c. Sin embargo, la cámara IVIS representa un nuevo enfoque para vigilar, caracterizar y, finalmente, entender el desarrollo en vivo de la enfermedad neumocócica siguientes infección por influenza A virus.

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

Durante la pandemia de gripe de 1918 el virus, que mató a unos 50 millones de personas en todo el mundo, la mayoría de las muertes no fueron el resultado de la infección con el virus de la influenza solo. En cambio, la mayoría de las personas se cree que han sucumbido a una infección bacteriana secundaria, principalmente causada por la bacteria Streptococcus pneumoniae (neumococo). La relación sinérgica entre las infecciones causadas por virus de la influenza y el neumococo posteriormente ha sido observado durante la pandemia de 1957, virus de la gripe asiática, así como durante los brotes estacionales de virus (revisado en 1, 2). Aquí se describe un protocolo que se utiliza para investigar el mecanismo (s) que pueden estar involucrados en aumento de la morbilidad como consecuencia de la influenza A virus concurrentes y S. pneumoniae infección. Hemos desarrollado un modelo murino bebé de forma fiable y reproducible demostrar los efectos de la infección por virus de la gripe de los ratones colonizados con S. pneumoniae. El uso de este protocolo, hemos proporcionado una primera visión de la cinética de la transmisión del neumococo entre los compañeros de alojados, los ratones recién nacidos con imágenes 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

Una infección concurrente con el virus de la influenza es uno de los factores implicados en la inducción de la enfermedad neumocócica invasiva en asintomáticos<em&gt; Streptococcus pneumoniae</em&gt; Carro. Aquí se describe un método de infección mixta con ratones lactantes para investigar la sinergia entre estos dos patógenos respiratorios.

Utilizando imágenes bioluminiscentes encargado de investigar la sinergia entre Streptococcus pneumoniae Y el Virus de la Influenza en ratones lactantes

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

using-bioluminescent-imaging-to-investigate-synergism-between

Research

JoVE Journal

Immunology and Infection

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

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Video: 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.

Imágenes de células vivas de Bacillus subtilis Y Streptococcus pneumoniae Automatizada utilizando Time-lapse microscopía

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

Investigación

Inmunología e Infección

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.

Imágenes bacteriana Bioluminiscente<em&gt; En 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.

Caracterización De Las Respuestas Inflamatorias Durante La Colonización Intranasal Con 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.

Vigilar los cambios en la polaridad de la membrana, membrana Integridad, e intracelular de iones concentraciones en<em&gt; Streptococcus pneumoniae</em&gt; Uso de tintes fluorescentes

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.

Capsular serotipificación de<em&gt; Streptococcus pneumoniae</em&gt; Uso de la Reacción 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.

Capsular Serotipificación de<em&gt; Streptococcus pneumoniae</em&gt; Por partículas de látex

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.

Propagación del virus de la influenza en embrionados de pollo Huevos

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.

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 ...

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.

Estudios de Virus de influenza A en un modelo murino de infección

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.

Medición de Influenza neutralizando las respuestas del anticuerpo al virus a (H3N2) en suero humano por microneutralización ensayos utilizando células de MDCK-SIAT1

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