Kill Virus ?!?!?

[chuinhen]

can I know how do viruses been eliminated by the body

since there is no cure to it .

[the tree]

Many apparent symptoms of the common cold are ways that the body attempts to get rid of a virus. For instance, a "fever" is the body increasing it's temperature to something that is uncomfortable for a human but lethal to a virus which can't handle the same extreems of temperature.

[Skye]

The key is that cells can recognise viruses. There are two aspects to it, when the virus is inside a cell and when the virus is in the fluids of the body. In the first case, early in the infection a cell can sometimes take parts of the virus and place them on its surface. Particular cells (mainly CD8+ T cells) then come and eat the cell. In the second case, viruses in the fluids of the body are detected and eaten by cells called phagocytes. They break down the virus and place the parts of the virus on their surface. Then CD4+ T cells come and some recognise the virus particle. They don't eat the phagocyte (snce its not infected) but instead release cytokines, which are mostly little proteins with sugars added to them. This is a signal, and once many cytokines are released, indicating that there's an infection. This then leads to the T cells releasing other cytokines (there are many different cytokines) which signal to other cells to become active. For viruses this is particularly macrophages, which go and eat the virus.

[chuinhen]

but wat happen if the body fails and the person fall sick ( common cold ) ??

wat will happen next to kill the virus although they lost !!!

[scicop]

huh..who lost what? "sickness" or rather symptoms of the common cold are just the side effects of our body erracdicating infection. As mentioned in the previous post, the cytokines, as well as a number of other compounds such as autocoids (histamine, bradykinin) and chemokines, are released during the containment and erradication of infection are pro-inflammatory (which is good during infection) which means ..very simply..that they are recruiting more leukocytes to battle infection.

 

There are side effects of these proinflam molecules, especially at the levels released during infection.

These effects are mediated by the release of membrane derived lipids that promote vasodilation and recruitment of leukocytes from circulation (Leukotriene B4 or Thromboxane A2). These same compounds are associated with "pain" that one may feel when one has a cold. Then there is the release of massive amounts of histamine (again vasodiliation/constrict in some areas) which can bring on sedation or tiredness.

 

There there is the action of the leukocytes..which expend alot of energy to erradicate infection (i.e. oxidative burst). So feeling sick in response to a cold is not a bad thing!! and no body is losing...well the virus is..but that how it works.

 

The story is different for other viruses other than the common cold, such as HIV, but in that case our defenses are either hijacked or out-smarted by the virus!!...but that's a whole different story..that you should look up now that you've had a immunology 101 lecture from two experts Skye on this forum and me...a former pharmaceutical industry science director who participated in the launch of a very big block buster anti-inflammatory drug! (which will remain nameless).