Flu Virus Disarms Immune System's First Responders

    26 November, 2013


    From VOA Learning English, this is the Health Report.

    Infection by the influenza virus may be more complex than scientists first thought. Researchers in the United States reported recently that the virus appears to disarm the body's first line of defense against disease.

    When the flu virus attacks, the body's natural defenses produce white blood cells. The cells make antibodies design to linkup to the invading microorganism, neutralize it, and in that way, prevent or at least lessen infection. The special cells also keep a memory of the invader so that the natural defenses can fight it again if the individual is re-infected. That is the traditional understanding of how the body fights the flu virus.

    Now, biologists have discovered how the virus can disarm those white blood cells, known as B cells. Hidde Ploegh led the team of researchers, he is with the Whitehead Institute for Biomedical Research in Cambridge, Massachusetts.

    Studies with genetically-bred mice suggest the flu virus enters the B cells and interferes with the production of antibodies, this can kill the cells and the body's first line of defense.

    If true, says Mr Ploegh, the process of infection may be more complex than scientists have thought.

    "And so we think that this really provides a new window on how the virus goes about its business. It may have implications in terms of explaining why certain strains of flu cause a nastier version of the disease than others," said Ploegh.

    Normally, the frontline antibodies occupy lung cells to protect the body against future viral invasion through breathing. 

    But the flu virus having disabled the antibodies, may instead target lung cells. In that way, the virus blocks the antibody's ability to remember the deadly invader, and labeling the virus to launch an attack on the body's defenses.

    "So this suggests that the initial encounter of the very type of white blood cell that we think defends us against the virus may be taken out by this initial wave of infection," said Ploegh.

    By neutralizing an interfering with the body's 'front line troops', Mr Ploegh says the flu virus has more time to reproduce and establish itself in the cells, that keeps the immune system from developing a second line of defense.

    A report on how influenza overcomes the body's immune system was published in the journal Nature.

    And that's the Health Report from VOA Learning English. You can read, listen and learn English with health news and more on our website 51voa.com. You can also watch our captioned videos at the VOA Learning English channel on YouTube. I'm Milagros Ardin.