H1N1 shares key similar structures to 1918 flu, providing research avenues for better vaccines

[HuckleB]

http://www.scientificamerican.com/blog/post.cfm?id=h1n1-shares-key-similar-structures-2010-03-24

"Despite viruses' reputation as constant shape-shifters, the recent pandemic flu (influenza A H1N1, 2009) bears an uncanny resemblance to the 1918 flu, new research has found. Two new studies, published online March 24 in Science and Science Translational Medicine, describe a small, but crucial structure that the two flu viruses share—and how that similarity might help prevent future outbreaks.

"Although the swine flu has a very different genetic composition and makeup within the inside, on the outside, this particular protein, which is called the hemagglutinin, looks very similar between the 1918 influenza virus and the swine flu," Ian Wilson, of the Department of Molecular Biology at The Scripps Research Institute in La Jolla, Calif. and co-author of the Science paper, explained in a podcast interview with Science.

These hemagglutinin look like tiny spikes on the virus's surface and are responsible for infecting other cells, but when an immune system learns to recognize a certain spike pattern on a particular virus strain, it will start an attack and usually prevent infection. Most circulating seasonal flu viruses have developed sugars on their surface that hide their hemagglutinin signatures, thereby helping them better evade the immune system's recognition.

Researchers in both of the new studies found that the 1918 flu (also an H1N1 strain) and the 2009 flu had so-called "bald head" hemagglutinin that weren't covered by sugars, but were instead nearly identical and easily recognized by an immune system that had been exposed to either. In fact, in the Science Translational Medicine study led by Chih-Jen Wei, of the National Institute of Allergy and Infectious Diseases (NIAID) at the National Institutes of Health, a team of researchers vaccinated groups of mice against either the 1918 strain or 2009 strain and then exposed each vaccinated mouse to the other virus. It turned out that exposure to either conferred protection against both, the researchers concluded.


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An eenteresting development, or so I say.

[MineralMan]

1. It's possible that the 1918 virus mutated further and

continued to be in the mix for many years after 1918, but still with similar characteristics. That might explain the lower rate of H1N1 flu in older people last year. I think the Hong Kong flu of whenever the heck that was was an H1 strain as well. I had that one.

[TZ]

2. There were also structural similarities to the swine flu of the late 70's

Which also accounted for many older people being resistant. Its good to know that this virus has all these similarities. Unless there is a huge mutation (still possible) it looks like we shouldn't have to worry about a SERIOUS pandemic of a fatal version.

[MineralMan]

3. They'll be including H1N1 in the seasonal vaccine this fall.

As you say, it would take a huge mutation for it to pose a high risk. I'll certainly be taking the vaccine, in any case.

I did get the Swine Flu vaccine in the 70s, too. Finally got an H1N1 vaccination this year, as well. I'm for all the protection I can muster.