Scientists Find Tiny Body - Key To How Vaccines Work

Discussion in 'Veterinary Discussion' started by Admin, Aug 23, 2018.

By Admin on Aug 23, 2018 at 12:06 PM
  1. Admin

    Admin Administrator Staff Member


    Sydney-based scientists have discovered a new structure inside your body that acts as one of the first lines of defence against disease – and may be the spot where vaccine-memory is held.

    The discovery, published Wednesday in top journal Nature Communications, may explain why we develop immunity to some diseases but not others.

    The tiny structure, about half the length of your pinky fingernail, sits inside lymph nodes on your neck and under your arms. It is small and almost-invisible when we are well, before enlarging when we are sick.

    Dr Imogen Moran, the 27-year-old PhD student who discovered it, and her supervisor at the Garvan Institute in Darlinghurst, Associate Professor Tri Phan, have named it the "subcapsular proliferative foci" or SPF.

    Associate Professor Tri Phan and Dr Imogen Moran.

    Photo: Nick Moir
    Lymph nodes are part of the body’s sewer system, making them an ideal spot to monitor for bacteria and viruses and the SPF waits there, when it spots a bad bug it activates a powerful immune response.

    The SPF allows the body to quickly spot and react to new diseases up to two days faster than without one, says Professor Phan.

    “Time is of the essence. The immune system really needs to control the infection very rapidly, or it will overwhelm the body. Bacteria can divide really quickly, so you have to stop them in their tracks or else you’re going to lose the game,” he says.

    A 3D reconstruction of the lymph node (in blue). The red cluster of cells in the centre, following the arc of the lymph node, is the SPF

    Photo: Garvan Institute of Medical Research
    The SPF is a dense cluster of immune cells: scout cells hunting for viruses, plus all the factory cells needed to make antibodies.

    When we’re not sick, it is tiny and almost invisible.

    When a scout cell spots a bug, the SPF expands rapidly. The factory cells go into overdrive, pumping out antibodies to kill the infection.

    By spotting the bug early, and having all the machinery ready to go, the body can kill the infection before it takes hold, says Professor Phan.

    The SPF in its enlarged state after it detects a disease.

    Photo: Garvan Institute of Medical Research
    Vaccines train certain cells in our body, known as memory cells, on what a virus looks like. Those memory cells can then recognise and kill the virus. Professor Phan believes many of those trained cells migrate to the SPF after a vaccine, where they sit and wait for a bug. He terms the structure the "seat of immune memory".

    That may explain why our body cannot seem to learn immunity to some diseases, such as malaria and HIV.

    It is possible the viruses aren’t flowing past the SPF – or the right cells aren’t getting into the structure, says Dr Kim Jacobson, who leads an immune-memory lab at Monash University and was not involved in the study.

    “By revealing the preferred location of immune memory survival and expansion, we can now try to get high-quality cells to the right place at the right time and help clear the infection before it can cause disease,” she says.

    Generations of scientists had missed the structure because of a quirk in the way we study anatomy.

    To study the lymph gland, where the SPF is found, researchers slice it up like a loaf of bread.

    The SPF is an extremely thin sheet that runs vertically through the lymph gland. Because they were looking just at thin horizontal slices, researchers never realised there was a separate structure running the length of the gland.



Discussion in 'Veterinary Discussion' started by Admin, Aug 23, 2018.

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