Naked Science Forum
Life Sciences => Cells, Microbes & Viruses => Topic started by: Emma Nason on 10/12/2009 09:30:02
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Emma Nason asked the Naked Scientists:
Hi, quick question that my students want to know...(just as H1N1 hits Uganda)...
We know that being exposed to surface proteins on a virus result in the production of antibodies to that protein. So, does an older person (who over the course of their life time has had multiple exposures to different influenza viruses), have a better chance of fighting off H1N1 than someone that has not been exposed to so many influenza viruses?
Thanks! Emma
Emma Nason PhD
Grade 6,8 Science and Grade 9,10 Biology Teacher
What do you think?
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A related issue is that autoimmune diseases tend to be, but are not exclusively, age related; they become more prevalent with increasing age.
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The one remarkable thing about the people who are dying {of swine flu} this time is that there haven’t been a lot of elderly people among them. That was noted in early reports from Mexico, and it raised some interest then, and that seems to be true in the United States now, too. All the people who have died whom I have heard about seem to be younger than 55.
This phenomenon may be similar to what happened in the 1918 flu pandemic, in which young adults were severely affected and many older adults were spared. One theory is that many older people may have survived the 1918 pandemic because they’d lived through the 1889-90 pandemic and may have been protected, or effectively vaccinated, by this earlier exposure.
http://news.medill.northwestern.edu/chicago/news.aspx?id=131077
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In a way there are. Lymphocytes recognizing an antigen start to multiply - cloning. The genes for the antibody that recognized the antigen have a region of high mutation rates - so some of the new cells have mutated antibodies. If some of these mutations produce better antibodies with higher affinity, the cells will be stimulated to multiply. Mutations will still occur, every improvement will be cloned more and more. A bit like natural selection on cellular level. So as you are older your antibodies become better and better - but only to micro-organisms that infected you.
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There was a similar "swine flu" outbreak in the 1970's so the thinking is that people already exposed to this virus will fight off H1N1 more easily. The novel part of the virus is the part derived from the pig virus, and this doesn't come along too often. So having the regular flu lots of times wouldn't protect you from the H1N1 since it is so different from the average flu.
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Yair Doza nailed it on the head. The process is called "Somatic Hypermutation".
Here is a wikipedia article regarding this process. http://en.wikipedia.org/wiki/Somatic_hypermutation
ATM, wikipedia is the best I can do, should you require more information from credible sources, I can comb my uni library.
Cheers.