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  • How the immune system recognises the flu

    http://www.scenta.co.uk/scenta/news....content_view_1


    How the immune system recognises the flu


    Source: scenta
    Scientists have completed the most extensive analysis of flu viruses.
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    Researchers at the La Jolla Institute for Allergy and Immunology (LIAI) in the United States drew upon a massive database established with funds from the National Institute of Allergy and Infectious Diseases (NIAID) to focus on influenza A virus epitopes.

    The findings are being published online this week by the journal Proceedings of the National Academy of Sciences.

    The study should help scientists who are designing new vaccines, diagnostics and immune-based therapies against seasonal and pandemic influenza because it reveals in molecular detail exactly where the immune system focuses on the viruses.

    Although the complete molecular structures of essentially all major strains of influenza viruses are known, immune responses concentrate on limited regions of certain parts of the virus, and these regions must be identified as immune epitopes by research studies.

    The LIAI team found that while there were hundreds of shared epitopes among different virus strains, including the avian H5N1 virus (bird flu), only one has been published that appears ideal for multi-strain vaccines.

    "This study is interesting for what it shows we know and do not know," says NIAID Director Dr Anthony S. Fauci.

    "It reveals many gaps in our knowledge of influenza viruses and indicates where we need to focus our attention."
    Recognising the antibodies that protect against the flu virus

    Influenza epitopes comprise of only a portion of the extensive database, which has become the largest single collection of such information anywhere in the world.

    "The purpose of the database is to provide a catalogue of molecules and structures that scientists around the world can quickly access and use to understand the immune response to a variety of epitopes, or methodically predict responses to as-yet untested targets," said Alessandro Sette, Ph.D., who heads the Vaccine Discovery division at LIAI and is the lead investigator on the project.

    For the current study, Dr. Sette and his colleagues examined 600 different epitopes from 58 different strains of influenza A virus.

    One of their main goals was to determine how conserved or similar epitopes are between different strains of bird and human influenza viruses.

    Knowing this is important because the virus rapidly mutates and can swap gene segments between strains, which could increase the ability of an avian virus to be transmissible to humans.

    In addition, only a handful of the epitopes are known to be associated with protective immunity.

    Most of the influenza virus epitopes in the database are those recognised by a type of immune cell known as a T cell, but far fewer are recognised by B cells - a type of white blood cell that produces infection-fighting antibodies.

    Antibodies induced by seasonal and pandemic flu viruses or vaccines are a major component of immunity that protects against these viruses.

    Strains of influenza virus can vary enough in their neutralising B cell epitopes that a vaccine that protects against one strain may not protect against another. But if epitopes are conserved between virus strains, a person?s immunity developed towards one strain might provide at least some protection against the other strain.

    Using a software tool they developed, the LIAI team found hundreds of conserved influenza virus epitopes in the database, including those between avian H5N1 and strains of human influenza viruses.

    But what is less clear from the analysis is how cross-reactive an immune response would be to most of these conserved epitopes.

    Further analyses may assist scientists in identifying vaccine targets that might offer broader protection and also in predicting how effective a new vaccine will be.

  • #2
    Re: How the immune system recognises the flu

    I think the article discussed is this one, it require a subscription I have'nt

    __________________________________________________ ______________
    http://www.pnas.org/cgi/content/full/104/1/246

    BIOLOGICAL SCIENCES / IMMUNOLOGY
    Ab and T cell epitopes of influenza A virus, knowledge and opportunities
    <nobr>Huynh-Hoa Bui<sup>*</sup></nobr>, <nobr>Bjoern Peters<sup>*</sup></nobr>, <nobr>Erika Assarsson<sup>*</sup></nobr>, <nobr>Innocent Mbawuike<sup></sup></nobr>, and <nobr>Alessandro Sette<sup>*</sup><sup>,</sup></nobr>
    *Division of Vaccine Discovery, La Jolla Institute for Allergy and Immunology, 9420 Athena Circle, La Jolla, CA 92037; and <sup></sup>Department of Molecular Virology, Baylor College of Medicine, Houston, TX 77030
    Communicated by Howard M. Grey, La Jolla Institute for Allergy and Immunology, San Diego, CA, November 1, 2006 (received for review October 1, 2006)

    The Immune Epitope Database and Analysis Resources (IEDB) (www.immuneepitope.org)<sup> </sup>was recently developed to capture epitope related data.
    <!-- ABS --> IEDB<sup> </sup>also hosts various bioinformatics tools that can be used to<sup> </sup>identify novel epitopes as well as to analyze and visualize<sup> </sup>existing epitope data. Herein, a comprehensive analysis was<sup> </sup>undertaken (i) to compile and inventory existing knowledge regarding<sup> </sup>influenza A epitopes and (ii) to determine possible cross-reactivities<sup> </sup>of identified epitopes among avian H5N1 and human influenza<sup> </sup>strains. At present, IEDB contains >600 different epitopes<sup> </sup>derived from 58 different strains and 10 influenza A proteins.<sup> </sup>By using the IEDB analysis resources, conservancy analyses were<sup> </sup>performed, and several conserved and possibly cross-reactive<sup> </sup>epitopes were identified. Significant gaps in the current knowledge<sup> </sup>were also revealed, including paucity of Ab epitopes in comparison<sup> </sup>with T cell epitopes, limited number of epitopes reported for<sup> </sup>avian influenza<sup> </sup>reported from proteins other than hemagglutinin and nucleoprotein.<sup> </sup>This analysis provides a resource for researchers to access<sup> </sup>existing influenza<sup> </sup>illustrates gaps in our collective knowledge that should inspire<sup> </sup>directions for further study of immunity against the influenza<sup> </sup>A virus. strains/subtypes, and limited number of epitopes epitope data. At the same time, the analysis

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