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  • Rights: The University of Waikato
    Published 18 October 2010 Referencing Hub media
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    Professor Graham Le Gros from the Malaghan Institute explains the body’s defence system. He talks about the first line of defence, which involves the skin barrier. He then talks about how pathogens1 can get behind this barrier into deeper tissues. This calls for the immune system2 – cells designed to hunt down and kill the worst bugs3 that we face.

    Transcript

    PROFESSOR GRAHAM LE GROS
    First of all, we have the basic skin barrier, and then underneath that, we have the blood. We all know pusy infections4 or pimples or whatever. Often they are the body’s first line of defence – the immune system immediately getting these white cells, which can actually kill off relatively harmless bugs.

    And then there are these things called pathogens, really nasty bugs. Flu virus5 is one, hookworm is another one, malaria6 is another one, tuberculosis7 – these bugs have learnt how to go behind the white blood cells, the pus cells, and start infecting the deeper tissues. And for that, we need what we call the adaptive immune system. These are cells specifically designed to really hunt down the worst bugs that we face, and they have specific weapons to kill them that the other white cells that cause the pus don’t have.

    So you have got to think about the immune system as layers, you know, first barriers, then first line of defence, the sort of marines, and then the more sophisticated nuclear guided missiles that come in later and get past all that etc. And it does a tremendous job of actually staying pretty calm, because when it sets off a nuclear missile, for instance, it damages the whole area, there is collateral damage, it doesn’t just get the bug8, it tends to get the bit of tissue around it. And that’s going back to what asthma9 and allergy10 is – you’ve actually got these immune system cells designed to kill parasites11, thinks the parasite12 is there, sets off its bombs, and there is a bit of collateral damage in the tissue around, thinking that is where the parasite is, and that causes the allergic disease13.

    Acknowledgement:
    Lucas Rucchin, I Stockphoto
    Jennifer Sieber
    Richard Sequeira, Maurice Wilkins Centre for MolecularBiodiscovery
    C. S. Goldsmith and A. Balish, CDC Centres for Disease Control & Prevention
    Creative Commons - Attribution 2.5 Generic
    Janice Haney Carr, CDC Centres for Disease Control14 & Prevention
    CDC Centres for Disease Control & Prevention
    Analytical Imaging Facility at the Albert Einstein College of Medicine.
    DR. RICHARD KESSEL & DR. GENE15 SHIH, VISUALS UNLIMITED /SCIENCE PHOTO LIBRARY
    BSIP LECAQUE/SCIENCE PHOTO LIBRARY
    uberstock I Stockphoto.com

    1. pathogen: A disease-causing organism.
    2. immune system: The natural defence system found in living things.  In humans, a network of organs, cells and proteins that helps to protect us against anything it recognises as being an ‘invader’ or ‘foreign’, for example, bacteria, viruses, cancer cells, parasites and transplanted organs and tissues. In plants, a network of disease resistance genes enable plants to detect and resist things like fungi, bacteria, viruses, nematodes and insects.
    3. bug: In biology, an informal term for an insect, insect-like creature, virus or other microorganism.
    4. infection: Invasion of the body or a species by something that could be harmful or cause a disease.
    5. virus: A microscopic infectious particle that can only multiply inside the cells of living organisms. They are capable of taking over the cell to produce copies of itself. They are inactive outside of a living host cell.
    6. malaria: An infectious disease caused by protozoa that are transmitted through the bite of an infected Anopheles mosquito.
    7. tuberculosis: Tuberculosis or TB (short for tubercle bacillus) is a common but often deadly bacterial infection that primarily affects the lungs.
    8. bug: In biology, an informal term for an insect, insect-like creature, virus or other microorganism.
    9. asthma: A common chronic inflammatory lung disease. It is an allergic disease caused by an immune disorder.
    10. allergy: A disorder of the immune system; a hypersensitivity to the reintroduction of an allergen. Allergic reactions occur to normally harmless substances.
    11. parasite: An organism that lives in or on another organism. Parasites usually cause harm to their host organism.
    12. parasite: An organism that lives in or on another organism. Parasites usually cause harm to their host organism.
    13. diseases: 1. An abnormal condition of an organism that impairs bodily functions. 2. In plants, an abnormal condition that interferes with vital physiological processes.
    14. control: 1. Part of a scientific experiment in which no treatment has been applied in order to see whether there are any detectable differences to the experiment that did receive a treatment. 2. To hold in check or to curb.
    15. genes: A segment of a DNA molecule that carries the information needed to make a specific protein. Genes determine the traits (phenotype) of the individual.
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      pathogen

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    2. A disease-causing organism.

      infection

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    4. Invasion of the body or a species by something that could be harmful or cause a disease.

      tuberculosis

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    6. Tuberculosis or TB (short for tubercle bacillus) is a common but often deadly bacterial infection that primarily affects the lungs.

      parasite

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    8. An organism that lives in or on another organism. Parasites usually cause harm to their host organism.

      genes

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    10. A segment of a DNA molecule that carries the information needed to make a specific protein. Genes determine the traits (phenotype) of the individual.

      immune system

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    12. The natural defence system found in living things. 

      In humans, a network of organs, cells and proteins that helps to protect us against anything it recognises as being an ‘invader’ or ‘foreign’, for example, bacteria, viruses, cancer cells, parasites and transplanted organs and tissues.

      In plants, a network of disease resistance genes enable plants to detect and resist things like fungi, bacteria, viruses, nematodes and insects.

      virus

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    14. A microscopic infectious particle that can only multiply inside the cells of living organisms. They are capable of taking over the cell to produce copies of itself. They are inactive outside of a living host cell.

      asthma

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    16. A common chronic inflammatory lung disease. It is an allergic disease caused by an immune disorder.

      diseases

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    18. 1. An abnormal condition of an organism that impairs bodily functions.

      2. In plants, an abnormal condition that interferes with vital physiological processes.

      bug

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    20. In biology, an informal term for an insect, insect-like creature, virus or other microorganism.

      malaria

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    22. An infectious disease caused by protozoa that are transmitted through the bite of an infected Anopheles mosquito.

      allergy

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    24. A disorder of the immune system; a hypersensitivity to the reintroduction of an allergen. Allergic reactions occur to normally harmless substances.

      control

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    26. 1. Part of a scientific experiment in which no treatment has been applied in order to see whether there are any detectable differences to the experiment that did receive a treatment.

      2. To hold in check or to curb.