Influenza A virus:
The type species of the genus Influenzavirus a that causes influenza and other diseases in humans and animals. Antigenic variation occurs frequently between strains, allowing classification into subtypes and variants. Transmission is usually by aerosol (human and most non-aquatic hosts) or waterborne (ducks). Infected birds shed the virus in their saliva, nasal secretions, and feces.
JoVE Immunology and Infection
Generation of Recombinant Influenza Virus from Plasmid DNA
1Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, 2Departments of Microbiology and Medicine, and Global Health and Emerging Pathogens Institute, Mount Sinai School of Medicine
Rescue of influenza A viruses from plasmid DNA is a basic and essential experimental technique that allows influenza researchers to generate recombinant viruses to study multiple aspects in the biology of influenza virus, and to be used as potential vectors or vaccines.
JoVE Immunology and Infection
Affinity Purification of Influenza Virus Ribonucleoprotein Complexes from the Chromatin of Infected Cells
Department of Virology, Universitätsklinikum Freiburg
Influenza viruses replicate their RNA genome in association with host-cell chromatin. Here, we present a method to purify intact viral ribonucleoprotein complexes from the chromatin of infected cells. Purified viral complexes can be analyzed by both Western blot and primer extension of protein and RNA content, respectively.
JoVE Immunology and Infection
Using Bioluminescent Imaging to Investigate Synergism Between Streptococcus pneumoniae and Influenza A Virus in Infant Mice
1Department of Microbiology and Immunology, University of Melbourne, 2Laboratory of Pediatric Infectious Diseases, Radboud University Nijmegen Medical Centre, 3The Centre for Dynamic Imaging, The Walter and Eliza Hall Institute for Medical Research
A concurrent infection with influenza A virus is one of the factors implicated in the induction of invasive pneumococcal disease during asymptomatic Streptococcus pneumoniae carriage. Here we describe a mixed infection method using infant mice to investigate the synergism between these two respiratory pathogens.
JoVE Immunology and Infection
Rapid Diagnosis of Avian Influenza Virus in Wild Birds: Use of a Portable rRT-PCR and Freeze-dried Reagents in the Field
1USGS Western Ecological Research Center, 2Wildlife Health Center, University of California, Davis, 3Department of Population Health and Reproduction, University of California, Davis, 4Department of Veterinary and Biomedical Sciences, University of Minnesota, 5Science Applications International Corporation
This study describes diagnosis of avian influenza in wild birds using a portable rRT-PCR system. The method takes advantage of freeze-dried reagents to screen wild birds in a non-laboratory setting, typical of an outbreak scenario. Use of molecular tools provides accurate and sensitive alternatives for rapid diagnosis.
JoVE Immunology and Infection
High-throughput Detection Method for Influenza Virus
1Laboratory of Molecular Immunology and Immunotherapy, Blood Research Institute, 2Department of Microbiology, Mount Sinai School of Medicine, 3Laboratory of Molecular Genetics, Blood Research Institute, 4City of Milwaukee Health Department Laboratory, 5Division of Hematology-Oncology/BMT, Children's Hospital of Wisconsin, Medical College of Wisconsin, 6Division of Hematology and Oncology, Dept Medicine, Medical College of Wisconsin
This method describes the use of Infrared dye based imaging system for detection of H1N1 in bronchioalveolar lavage (BAL) fluid of infected mice at a high sensitivity. This methodology can be performed in a 96- or 384-well plate, requires <10 μl volume of test material and has the potential for concurrent screening of multiple pathogens.
JoVE Immunology and Infection
ampliPHOX Colorimetric Detection on a DNA Microarray for Influenza
InDevR, Inc.
ampliPHOX colorimetric detection technology is presented as an inexpensive alternative to fluorescence detection for microarrays. Based on photopolymerization, ampliPHOX produces solid polymer spots visible to the naked eye in just a few minutes. Results are then imaged and automatically interpreted with a simple yet powerful software package.
JoVE Editorial
August 2011: This Month in JoVE
Here are some highlights from the August 2011 Issue of Journal of Visualized Experiments (JoVE).
JoVE Immunology and Infection
Quantitative Analyses of all Influenza Type A Viral Hemagglutinins and Neuraminidases using Universal Antibodies in Simple Slot Blot Assays
1Centre for Vaccine Evaluation, Biologics and Genetic Therapies Directorate, HPFB, Health canada, 2National Institute for the Control of Pharmaceutical and Biological Products, The State Food and Drug Administration, Beijing, 3Department of Biochemistry, Microbiology and Immunology, University of Ottawa, 4Microbiology Department, Faculty of Medicine, King Abdulaziz University, 5National Microbiology Laboratory, Public Health Agency of Canada
A simple slot blot method was developed for the quantification of influenza viral hemagglutinin and neuraminidase using universal antibodies targeting their most conserved sequences identified through bioinformatics analyses. This innovative approach may provide a useful alternative to quantitative determination of all viral hemagglutinin and neuraminidase.
JoVE Bioengineering
Microfluidic Chip Fabrication and Method to Detect Influenza
1Department of Mechanical Engineering, Boston University, 2Department of Biomedical Engineering, Boston University
An integrated microfluidic thermoplastic chip has been developed for use as a molecular diagnostic. The chip performs nucleic acid extraction, reverse transcriptase, and PCR. Methods for fabricating and running the chip are described.
JoVE Immunology and Infection
Avian Influenza Surveillance with FTA Cards: Field Methods, Biosafety, and Transportation Issues Solved
1Resource Ecology Group, Wageningen University, 2Section for Zoonotic Ecology and Epidemiology, School of Natural Sciences, Linnaeus University, 3Centre for Wildlife Ecology, Simon Fraser University
A method to preserve, detect and sequence RNA from Avian Influenza Viruses was validated and extended using natural faecal samples from birds. This technique removes the necessity of maintaining a cool chain and handling of infectious viruses and can be applied in a 96-well high-throughput setup.
JoVE General
Purification and Visualization of Influenza A Viral Ribonucleoprotein Complexes
Department of Zoology, University of British Columbia - UBC
The genome of the influenza A virus consists of eight separate complexes of RNA and proteins, termed viral ribonucleoprotein complexes (vRNPs). This paper describes the glycerol gradient purification and transmission electron microscopy visualization of influenza A vRNPs.
JoVE General
Method for Measurement of Viral Fusion Kinetics at the Single Particle Level
1Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 2Howard Hughes Medical Institute, Harvard Medical School
We present an in vitro, two-color fluorescence assay to visualize the fusion of single virus particles with a fluid target bilayer. By labeling viral particles with fluorophores that differentially stain the viral membrane and its interior, we are able to monitor the kinetics of hemifusion and pore formation.
JoVE Immunology and Infection
Glass Wool Filters for Concentrating Waterborne Viruses and Agricultural Zoonotic Pathogens
1Wisconsin Water Science Center, United States Geological Survey, 2University of Wisconsin – Madison, 3Agricultural Research Service, United States Department of Agriculture, 4Alaska Science Center, United States Geological Survey
Glass wool filters have been used to concentrate waterborne viruses by a number of research groups around the world. Here we show a simple approach for constructing glass wool filters and demonstrate the filters are also effective in concentrating waterborne viral, bacterial and protozoan pathogens.
JoVE Immunology and Infection
Flow Cytometric Isolation of Primary Murine Type II Alveolar Epithelial Cells for Functional and Molecular Studies
1Research Group Immune Regulation, Helmholtz Centre for Infection Research, 2Research Group Infection Immunology, Institute of Medical Microbiology, Otto-von-Guericke University, 3Department of Experimental Immunology, Helmholtz Centre for Infection Research
We describe the rapid isolation of primary murine type II alveolar epithelial cells (AECII) by flow cytometric negative selection. These AECII show high viability and purity and are suitable for a wide range of functional and molecular studies regarding their role in respiratory conditions such as autoimmune or infectious diseases.
JoVE Immunology and Infection
Using a Pan-Viral Microarray Assay (Virochip) to Screen Clinical Samples for Viral Pathogens
1Department of Laboratory Medicine, University of California, San Francisco, 2Division of Infectious Diseases, University of California, San Francisco
The Virochip is a pan-viral microarray designed to simultaneously detect all known viruses as well as novel viruses on the basis of conserved sequence homology. Here we demonstrate how to run a Virochip assay to analyze clinical samples for the presence of both known and unknown viruses.
JoVE Immunology and Infection
Isolation of Mouse Peritoneal Cavity Cells
BloodCenter of Wisconsin, Blood Research Institute
The peritoneal cavity in mammals contains different immune cell populations crucial for innate immune responses. An efficient isolation method is required for biochemical and functional analyses of these cells. Here we provide a comprehensive method for the isolation of peritoneal cavity cells in the mouse.
JoVE Immunology and Infection
RNAi Screening for Host Factors Involved in Vaccinia Virus Infection using Drosophila Cells
Department of Microbiology, Penn Genome Frontiers Institute, University of Pennsylvania
Novel host factors involved in viral infection can be identified through cell-based genome-wide loss of function RNAi screening. A Drosophila cell culture model is particularly amenable to this approach due to the ease and efficiency of RNAi. Here we demonstrate this technique using vaccinia virus as an example.
JoVE General
Extraction of Tissue Antigens for Functional Assays
1Immunology and Diabetes Unit, St. Vincent's Institute of Medical Research, 2Department of Medicine, University of Melbourne
A simple protocol for preparing extracts of human tissue to be used as a source of antigens in functional T-cell assays is described. This method allows T-cell responses to tissue-derived antigens to be measured in vitro.
JoVE Immunology and Infection
Protocol for Recombinant RBD-based SARS Vaccines: Protein Preparation, Animal Vaccination and Neutralization Detection
Lindsley F. Kimball Research Institute, New York Blood Center
This protocol describes a general procedure for studying recombinant receptor-binding domain (RBD)-based subunit vaccines against SARS. It includes methods for transfection and expression of RBD protein in 293T cells, immunization of mice with RBD and detection of neutralization activity of mouse sera using an established SARS pseudovirus neutralization assay.
JoVE Immunology and Infection
Isolation of Mouse Lung Dendritic Cells
Pathobiological Sciences, Louisiana State University
A highly purified preparation of mouse lung dendritic cells is described. Specific emphasis is given to the isolation of conventional dendritic cell subset.
JoVE Immunology and Infection
Determining the Phagocytic Activity of Clinical Antibody Samples
1Massachusetts General Hospital, Ragon Institute of MGH, MIT, and Harvard, 2Thayer School of Engineering, Dartmouth College
We present a high-throughput flow cytometric assay to determine the phagocytic activity of antigen-specific antibodies from clinical samples, utilizing fluorescent antigen-coated beads and a monocytic cell line expressing multiple Fc receptors—providing receptor usage and phagocytic activity determinations in a standardized and reproducible fashion for any antigen of interest.
JoVE Immunology and Infection
Establishing a Liquid-covered Culture of Polarized Human Airway Epithelial Calu-3 Cells to Study Host Cell Response to Respiratory Pathogens In vitro
The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention.
JoVE Immunology and Infection
Parasite Induced Genetically Driven Autoimmune Chagas Heart Disease in the Chicken Model
Chagas Disease Multidisciplinary Research Laboratory, University of Brasilia
The inoculation of Trypanosoma cruzi in fertile eggs prior to incubation renders the parasite kDNA minicircle integration in embryo cells genome. Crossbreeding reveals the vertical transfer of the mutations to progeny. The kDNA integrates into coding regions at several chromosomes and the chickens die with an inflammatory autoimmune heart disease.
JoVE Immunology and Infection
Quantitative Imaging of Lineage-specific Toll-like Receptor-mediated Signaling in Monocytes and Dendritic Cells from Small Samples of Human Blood
Department of Internal Medicine, Yale University School of Medicine
We describe use of ImageStream technology (www.amnis.com), which combines quantitative flow cytometry with simultaneous high-resolution digital imaging, to quantify cellular mechanisms of primary immune cells from well-defined patient cohorts. Our studies provide a blueprint for translational investigations to quantify lineage specific cellular responses in small samples from subject cohorts.
JoVE Immunology and Infection
Quantitative Measurement of the Immune Response and Sleep in Drosophila
Center for Sleep and Circadian Neurobiology, University of Pennsylvania Perelman School of Medicine
To understand a link between the immune response and behavior, we describe a method to measure locomotor behavior in Drosophila during bacterial infection as well as the ability of flies to mount an immune response by monitoring survival, bacterial load, and real-time activity of a key regulator of innate immunity, NFκB.
JoVE Immunology and Infection
Examining the Role of Nasopharyngeal-associated Lymphoreticular Tissue (NALT) in Mouse Responses to Vaccines
U.S. Army Medical Research Institute of Infectious Diseases
Methods to examine contributions of the nasopharyngeal-associated lymphoreticular tissues (NALT) to nasal and systemic immune responses of mice to intranasal vaccines are described. We demonstrate a surgical procedure to establish a NALT-dependent mouse model and ex vivo cultures of extracted NALT.
JoVE Chemistry
Production of Disulfide-stabilized Transmembrane Peptide Complexes for Structural Studies
1Structural Biology Division, The Walter and Eliza Hall Institute of Medical Research, 2The University of Melbourne
Biophysical and biochemical studies of interactions among membrane-embedded protein domains face many technical challenges, the first of which is obtaining appropriate study material. This article describes a protocol for producing and purifying disulfide-stabilized transmembrane peptide complexes that are suitable for structural analysis by solution nuclear magnetic resonance (NMR) and other analytical applications.
JoVE General
Visualizing Antigen Specific CD4+ T Cells using MHC Class II Tetramers
1Tetramer Core Laboratory, Benaroya Research Institute, 2Kwok Laboratory, Benaroya Research Institute, 3Nepom Laboratory, Benaroya Research Institute
This procedure demonstrates the purification and in vitro expansion of antigen specific CD4+ T cells from whole peripheral blood and their visualization using MHC class II tetramers. Tetramers permit the direct visualization of T cells with a single antigen specificity and defined MHC class II restriction.
JoVE General
Chemically-blocked Antibody Microarray for Multiplexed High-throughput Profiling of Specific Protein Glycosylation in Complex Samples
1Institute for Hepatitis and Virus Research, 2Department of Microbiology and Immunology, Thomas Jefferson University, 3Drexel University College of Medicine, 4Van Andel Research Institute, 5Institute for Hepatitis and Virus Research, Serome Biosciences Inc.
In this study, we describe an improved protocol for a multiplexed high-throughput antibody microarray with lectin detection method that can be used in glycosylation profiling of specific proteins. This protocol features new reliable reagents and significantly reduces the time, cost, and lab equipment requirements as compared to the previous procedure.
JoVE Neuroscience
Stereotaxic Injection of a Viral Vector for Conditional Gene Manipulation in the Mouse Spinal Cord
1Département Nociception et Douleur, Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique (CNRS), 2Departments of Anesthesiology and Pharmacology, Columbia University, 3Department of Anesthesiology, Niigata University Graduate School of Medical and Dental Sciences
Viral vectors allow for targeted gene manipulation. We demonstrate a method for conditional gene expression or ablation in the mouse spinal cord, using stereotaxic injection of a viral vector into the dorsal horn, a prominent site of synaptic contact between primary somatosensory afferents and neurons of the central nervous system.
JoVE Immunology and Infection
Estimating Virus Production Rates in Aquatic Systems
Department of Microbiology, University of Tennessee
The turnover rate of viruses in marine and freshwater systems can be estimated by a reduction and reoccurrence technique. The data allow researchers to infer rates of virus-mediated microbial mortality in aquatic systems.
JoVE Immunology and Infection
Isolation of Fidelity Variants of RNA Viruses and Characterization of Virus Mutation Frequency
Viral Populations and Pathogenesis lab and CNRS 3015, Institut Pasteur
The present article describes the steps required to isolate and characterize RNA polymerase fidelity variants of RNA viruses and how to use mutation frequency data to confirm fidelity changes in tissue culture.
JoVE Immunology and Infection
Visualizing Dengue Virus through Alexa Fluor Labeling
1Defence Medical and Environmental Research Institute, DSO National Laboratories, 2Program in Emerging Infectious Diseases, Duke-NUS Graduate Medical School, 3Program in Emerging Infectious Diseases, Duke-NUS Graduate Medical School
Taking advantage of the advancements in fluorophore development and imaging technology, a simple method of Alexa Fluor labeling of dengue virus was devised to visualize the early interactions between virus and cell.
JoVE Neuroscience
Intracranial Injection of Adeno-associated Viral Vectors
Neurobiology and Anatomy, University of Rochester
Here we present the intracranial injection of AAV vectors for fluorescent labeling of neurons and glia in the visual cortex.
JoVE General
Lentivirus Production
Diabetes Center, University of California, San Francisco - UCSF
To make lentiviruses, DNA vectors are transfected into human 293 cells. After harvest and concentrating the supernatant, virus titer is determined by fluorescence expression with a flow cytometer.
JoVE Immunology and Infection
Particle Agglutination Method for Poliovirus Identification
1Department of Virology II, National Institute of Infectious Diseases, 2New Product Design Department, Fujirebio Inc.
A recently developed novel particle agglutination (PA) assay utilizing virus receptor molecule allowed a rapid and easy identification of poliovirus (PV). In this article, we will show the procedure for the PA assay for PV identification.
JoVE Immunology and Infection
Alphavirus Transducing System: Tools for Visualizing Infection in Mosquito Vectors
Microbiology, Immunology, and Pathology, Colorado State University
Methods for using alphavirus transducing systems to express fluorescent reporters in vitro and in adult mosquitoes are described. This technique may be adapted to express any protein of interest in lieu of or in addition to a reporter.
JoVE General
Transduction of Human Cells with Polymer-complexed Ecotropic Lentivirus for Enhanced Biosafety
Department of Cell Biology and Human Anatomy, School of Medicine, University of California, Davis
Lentiviruses are a valuable research tool for exploring gene function; however, researchers may wish to avoid production of pantropic lentivirus encoding known or suspected oncogenes. As an alternative, we present a safer protocol for use of ecotropic lentivirus on human cells modified to express the ecotropic receptor mSlc7a1.
JoVE Immunology and Infection
Detection of Infectious Virus from Field-collected Mosquitoes by Vero Cell Culture Assay
We describe a method to process and screen field-collected mosquitoes for a diversity of viruses by Vero cell culture assay. By employing this technique, we have detected 9 different viruses from 4 taxonomic families in mosquitoes collected in Connecticut.
JoVE Immunology and Infection
Analysis of the Solvent Accessibility of Cysteine Residues on Maize rayado fino virus Virus-like Particles Produced in Nicotiana benthamiana Plants and Cross-linking of Peptides to VLPs
1Plant Sciences Institute, Agricultural Research Service, United States Department of Agriculture, 2Molecular Plant Pathology Laboratory, Agricultural Research Service, United States Department of Agriculture
A method to analyze the solvent accessibility of the thiol group of cysteine residues of Maize rayado fino virus (MRFV)-virus-like particles (VLPs) followed by a peptide cross-linking reaction is described. The method takes advantage of the availability of several chemical groups on the surface of the VLPs that can be targets for specific reactions.
JoVE General
Production of Replication-Defective Retrovirus by Transient Transfection of 293T cells
Molecular Oncology Research Institute, Tufts University
This technique demonstrates an efficient way to prepare replication-defective retroviral stocks encoding a human oncogene, and subsequently used for induction of myeloproliferative disease in the mouse model.
JoVE Immunology and Infection
Measurement of γHV68 Infection in Mice
Department of Molecular Microbiology and Immunology, University of Southern California, Los Angeles
γ-Herpesviruses (γ-HVs) establish life-long persistency in their host. Infection of mice with γ-HV68 provides a genetically tractable in vivo model for the characterization of the lifecycle/pathogenesis of γHVs. This protocol describes the detection and quantitation of γHV68 infection at acute and latent stages following infection by plaque-forming, infectious center, and qPCR assays.
JoVE Neuroscience
Viral Tracing of Genetically Defined Neural Circuitry
1Department of Genetics, Harvard Medical School, 2Howard Hughes Medical Institute, Harvard Medical School
A method of tracing synaptically connected neurons is described. We use TVA specificity of an upstream cell to probe whether a cell population of interest receives synaptic input from genetically defined cell types.
JoVE Immunology and Infection
Propagating and Detecting an Infectious Molecular Clone of Maedi-visna Virus that Expresses Green Fluorescent Protein
Institute for Experimental Pathology, University of Iceland
We describe a molecular clone of maedi-visna virus that expresses GFP and is fully infectious. Replication of this virus can be detected by using fluorescence microscopy and flow cytometry.
JoVE Immunology and Infection
Efficient Recombinant Parvovirus Production with the Help of Adenovirus-derived Systems
1Tumour Virology Division F010, German Cancer Research Center (DKFZ), 2Inserm Unit 701, German Cancer Research Center (DKFZ)
Here we describe a protocol based only on cell infection, which improves the efficiency of recombinant parvovirus production by more than 100 fold in comparison to other protocols in use. This protocol relies on the use of a novel adenovirus 5-based helper containing the parvovirus VP transcription unit (Ad-VP).
JoVE Neuroscience
Mosaic Analysis of Gene Function in Postnatal Mouse Brain Development by Using Virus-based Cre Recombination
1Neuroscience Graduate Program, Keck School of Medicine, University of Southern California, 2Zilkha Neurogenetic Institute, University of Southern California, 3Department of Cell and Neurobiology, Neuroscience Graduate Program, Keck School of Medicine, University of Southern California
An in vivo method to test gene function in postnatal brain is described. Recombinant AAVs expressing Cre and/or a fluorescent protein are injected into neonatal mouse brain. Mosaic gene inactivation and sparse neuronal labeling are achieved, allowing rapid analysis of gene function in processes critical to neural circuit development.
JoVE General
Protocol for Dengue Infections in Mosquitoes (A. aegypti) and Infection Phenotype Determination
Malaria Research Institute, Bloomberg School of Public Health, Johns Hopkins University
Once a gene is identified as potentially refractory for the dengue virus, it must be evaluated for it's role in preventing viral infections within the mosquito. This protocol illustrates how the extent of dengue infections of mosquitoes can be assayed. The techniques for growing up the virus in culture, membrane feeding mosquitoes human blood, and assaying viral titers in the mosquito midgut are demonstrated.
JoVE General
Vaccinia Virus Infection & Temporal Analysis of Virus Gene Expression: Part 1
Whitehead Institute for Biomedical Research, MIT - Massachusetts Institute of Technology
Protocol for Vaccinia infection of HeLa cells and analysis of host and viral gene expression. Part 1 of 3.
JoVE Clinical and Translational Medicine
Gene Transfer for Ischemic Heart Failure in a Preclinical Model
Cardiovascular Research Center, Mount Sinai School of Medicine
A method of gene transfer for the treatment of ischemic heart failure is described using a swine model of myocardial infarction. Our simple and reproducible method enables us to readily evaluate the efficacy of various gene transfers with a very simple and reproducible way.
JoVE Immunology and Infection
Chemoselective Modification of Viral Surfaces via Bioorthogonal Click Chemistry
Department of Chemistry, Stony Brook University
Adenovirus particles are engineered to contain either the unnatural amino acid analogue azidohomoalanine or the azido sugar O-GlcNAz. The azide group of each is chemoselectively ligated via "click" chemistry reactions as a means of viral surface modification.
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