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Does the immune system destroy virus infected cells?

by sameeralord
Tags: cells, destroy, immune, infected, virus
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sameeralord
#1
Jul28-09, 11:15 AM
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What happens when virus invades a host cell, reproduces and then leaves without destroying the host cell. Then does the immune system destroy these infected host cells? How do viruses do damage. Is it simply by leaving the host cell and destroying it?If bacteria can enter the cell without destroying it why can't it leave the same way?
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kldickson
#2
Jul28-09, 12:47 PM
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By definition, a virus cannot leave the host cell without destroying it; it kills the cell in a process called lysis, which breaks the cell membrane. Bacterial infection causes lysis as well.
Monique
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Jul29-09, 09:50 AM
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The immune system can recognize cells that are infected by viruses, once the cell starts to display the virus's proteins on class I MHC molecules on the outside of the cell.

sameeralord
#4
Jul29-09, 11:41 AM
P: 640
Does the immune system destroy virus infected cells?

Quote Quote by Monique View Post
The immune system can recognize cells that are infected by viruses, once the cell starts to display the virus's proteins on class I MHC molecules on the outside of the cell.
Thanks However when the virus is engulfed don't the cell engulf the receptor complex that was binded to the virus as well. So how do these receptors remain?
sameeralord
#5
Jul29-09, 11:58 AM
P: 640
Just did a research on MHC molecules and understood what you meant MHC markers basically show to the extracellular environment what proteins are made inside. Thanks Monique for your help Thanks for kldickson as well but Moniques answer was what I was after.
Ygggdrasil
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Jul29-09, 01:27 PM
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It's also worth noting that some viruses integrate their genome into the host cell and lay dormant prior to replicating and lysing the cell (notable examples include retroviruses like herpes simplex and HIV). In these cases, I'm not sure whether the immune system would recognize these infected cells as they would not be actively producing viral proteins in this latent stage (perhaps someone with a better knowledge of immunology can correct me).
Monique
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Jul30-09, 04:55 PM
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Quote Quote by sameeralord View Post
Just did a research on MHC molecules and understood what you meant MHC markers basically show to the extracellular environment what proteins are made inside. Thanks Monique for your help Thanks for kldickson as well but Moniques answer was what I was after.
You're welcome. What do you think would happen if a virus is so smart to stop class I MHC molecules from reaching the extracellular domain? (in which case the virus's proteins will not be displayed to the immune system, which would be a survival mechanism)
Monique
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Jul30-09, 05:03 PM
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Quote Quote by Ygggdrasil View Post
It's also worth noting that some viruses integrate their genome into the host cell and lay dormant prior to replicating and lysing the cell (notable examples include retroviruses like herpes simplex and HIV). In these cases, I'm not sure whether the immune system would recognize these infected cells as they would not be actively producing viral proteins in this latent stage (perhaps someone with a better knowledge of immunology can correct me).
If the virus is dormant, it won't be recognized. Most people carry viruses around for life, such as Cytomegalovirus or Epstein-Barr virus.
sameeralord
#9
Jul31-09, 01:21 AM
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Quote Quote by Monique View Post
You're welcome. What do you think would happen if a virus is so smart to stop class I MHC molecules from reaching the extracellular domain? (in which case the virus's proteins will not be displayed to the immune system, which would be a survival mechanism)
Jeez!! Are their viruses like that? Then what do we do. Are we gone or can the immune system detect the virus when it on the way to another host cell? So would the host cells keep creating viruses?
Monique
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Jul31-09, 05:45 AM
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Quote Quote by sameeralord View Post
Jeez!! Are their viruses like that? Then what do we do. Are we gone or can the immune system detect the virus when it on the way to another host cell? So would the host cells keep creating viruses?
Yes, there are viruses like that (tumors as well), but our body behaves in a smart way: cells that do not display class I MHC molecules are lysed by the natural killer (NK) cells of our immune system
sameeralord
#11
Aug4-09, 02:56 AM
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Quote Quote by Monique View Post
Yes, there are viruses like that (tumors as well), but our body behaves in a smart way: cells that do not display class I MHC molecules are lysed by the natural killer (NK) cells of our immune system
Can NK cells detect virus infected cells without MHC markers. How do they do that?
Monique
#12
Aug6-09, 06:22 AM
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No, they kill any cell that does not have the MHC molecules (since that is a dangerous condition).
sameeralord
#13
Aug7-09, 04:13 AM
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Quote Quote by Monique View Post
No, they kill any cell that does not have the MHC molecules (since that is a dangerous condition).
Thanks Monique for replying every question Our body is not that bad after all!!


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