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From VOA Learning English, |
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this is the Health Report. |
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Infection by the influenza virus may be |
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more complex than scientists first thought. |
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Researchers in the United States reported recently |
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that the virus appears to disarm |
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the body's first line of defense against disease. |
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When the flu virus attacks, |
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the body's natural defenses produce white blood cells. |
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The cells make antibodies design to linkup |
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to the invading microorganism, neutralize it, |
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and in that way, prevent or at least lessen infection. |
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The special cells also keep a memory of the invader |
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so that the natural defenses can fight it again |
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if the individual is re-infected. |
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That is the traditional understanding of |
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how the body fights the flu virus. |
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Now, biologists have discovered how the virus |
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can disarm those white blood cells, known as B cells. |
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Hidde Ploegh led the team of researchers, |
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he is with the Whitehead Institute |
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for Biomedical Research in Cambridge, Massachusetts. |
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Studies with genetically-bred mice suggest |
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the flu virus enters the B cells |
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and interferes with the production of antibodies, |
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this can kill the cells and the body's first line of defense. |
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If true, says Mr Ploegh, the process of infection |
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may be more complex than scientists have thought. |
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"And so we think that this really provides a new window |
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on how the virus goes about its business. |
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It may have implications in terms of explaining |
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why certain strains of flu cause a nastier version |
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of the disease than others," said Ploegh. |
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Normally, the frontline antibodies |
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occupy lung cells to protect the body |
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against future viral invasion through breathing. |
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But the flu virus having disabled the antibodies, |
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may instead target lung cells. |
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In that way, the virus blocks the antibody's ability |
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to remember the deadly invader, and labeling the virus |
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to launch an attack on the body's defenses. |
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"So this suggests that the initial encounter |
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of the very type of white blood cell |
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that we think defends us against the virus |
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may be taken out by this initial wave of infection," said Ploegh. |
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By neutralizing an interfering with the body's 'front line troops', |
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Mr Ploegh says the flu virus has more time |
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to reproduce and establish itself in the cells, |
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that keeps the immune system |
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from developing a second line of defense. |
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A report on how influenza overcomes the body's immune system |
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was published in the journal Nature. |
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And that's the Health Report from VOA Learning English. |
