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Offline nina

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influenza virus
« on: 11/08/2005 09:50:11 »
I have questions about the influenza virus. I'm hoping someone here can give me answers..:)
Which are the host cells of the influenza virus? Is it correct, that the virus binds to sialic acid residues of glycosylated receptor proteins? Are these sialic acid residues common components of glycosylated proteins on many cell types? What are the immune responses to influenza virus (antibodies, killer T-cells, etc.)? How does the symptoms of  influenza arise?


 

Offline chris

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Re: influenza virus
« Reply #1 on: 11/08/2005 18:39:44 »
Hi Nina

Human influenza particles (e.g. A/B) use their coat HA (haemagglutinin) molecules to lock onto sialic acid groups on the surfaces of epithelial cells lining the upper respiratory tract. The virus then employs a second protein to mediate cell penetration.

A cascade of gene expression then ensues leading to the formation of new RNA genomes, synthesis of viral structural proteins, particle assembly, budding from the cell surface and cleavage (which releases the mature particle).

As with any viral infection, immunity is cell and antibody mediated. Cytotoxic and NK T cells identify virally-infected cells and remove them, but only once they have been primed to attack. Clearance of the infection culminates in the production of neutralising IgG antibodies capable of providing protection against future bouts of the disease.

For a summary of the story, here's a link to my article about influenza (flu) infection, diagnosis and treatment.

Chris

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Offline Razor

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Re: influenza virus
« Reply #2 on: 12/08/2005 10:30:46 »
............I'll return when i have some knowledge on it.

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http://www.compfused.com/directlink/132
 

Offline nina

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Re: influenza virus
« Reply #3 on: 12/08/2005 13:44:58 »
Thanks a lot for the answer! :) I got a bit confused concerning influenza and the host cells because I was reading in a biochemistry book that the HA of the influenza virus specifically binds to glycophorin A in erytrocytes. As influenza really is an infection of the respiratory tract, I can't understand that erytrocytes would be important host cells(?)

 

Offline chris

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Re: influenza virus
« Reply #4 on: 12/08/2005 19:22:17 »
You're right. Flu binds to the sialic acid on the surface of the erythrocytes. That's not to say that it often enters the bloodstream (termed viraemia) because it usually remains confined to the respiratory tract. Occasionally, however, mainly in severe infections as typified by pandemic (avian) flu strains, it can begin to disseminate haematogenously.

However, the binding of flu to red blood cells provides us with a very convenient test for the presence of the virus called a haemagglutination test, or a haemabsorption test. In these tests red cells are mixed with samples containing flu which cross-links the red cells together, forming a cell raft and highlighting the presence of the virus.

Chris

"I never forget a face, but in your case I'll make an exception"
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Offline nina

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Re: influenza virus
« Reply #5 on: 15/08/2005 09:43:24 »
Great, now I understand these things about influenza and host cells!
 

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Re: influenza virus
« Reply #5 on: 15/08/2005 09:43:24 »

 

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