Antibodies Disappear

[Mae6294]

This is something that has been bugging me for a while. If you get a viral illness (any kind that can be treated) and have an IgG antibody blood test done it comes out positive because you are infected. Now lets say you went through treatment and cured the Virus meaning its no longer in your body, after the rough 3 weeks of the IgG antibody's half life will the levels of your antibodies go down due to the virus no longer being in your body? Will this then lead to (after the right amount of time) a IgG antibody test to become negative?

I know the body makes Bmemory cells that will remember the pathogen (viral or bacterial) which is why vaccines work, but do the antibodies actual disappear to lower levels until another exposure to that virus?

Thanks for reading and commenting!

[Mae6294]

Thank you. One last thing because I know that immunology will cover the rest. What does 3 week half life actually mean with IgG antibodies?

[Neuromedstudent]

That is awesome! A very honorable pursuit. I wish you the best of luck with your studies.

[Mae6294]

Im a pre-med I hope to be an Doctor of Osteopathic Family practice and Osteopathic Manipulative Therapy or a DO anesthesiologist. Im taking Exercise science with a minor in biology and chemistry for my undergrads Im a sophomore at the moment. Im taking immunology in spring of 2015 but a few students at school were talking about antibodies and most of them said you never get rid of them and It didn't seem right to me because they are a protein and can change shape eventually!

[Neuromedstudent]

I forgot to leave the link...sorry:(
http://www.ncbi.nlm.nih.gov/books/NBK27144/

[Neuromedstudent]

Here is a link that roughly describes their shape and conformation. It is a reputable source. If this does not clarify let me know and I would be happy to explain. The answer to that one, though it may seem easy and quick, is not exactly. Let me know!

What are you studying? Are you an undergrad?

[Mae6294]

Thank you so much!

Some students at school were talking about antibodies. Some said the IgG antibodies last forever and some were not sure. I was sure, since they were proteins, eventually all antibodies even the IgGs will go away once the Bacteria or Virus is completely gone from the body. Assuming the  type of Virus in the body doesn't have the escape route to become dormant in some cells in the body! :)

I know IgG take the longest to change shape and deform from the active antibody, but do you know roughly how long before that happens?

[Neuromedstudent]

You got it!

Ok, so IgG antibodies are the most abundant and are only activated by T helper cells during the secondary immune system response. So that is to say after some has been memorized by the host immune system. IgG attached to the bacteria cells and coats it for opsinization. This is the process that enables lysozomes to perform phagocytosis on the bacterial cell, aka killing it. It acts sort of like a huge red flag that says hey I got one right here come kill it. lol. Anyway as the bacterial cell is lysed the IgG is basically rendered useless as it is only a protein and it swallowed by the lysozome. This is why the count eventually goes down as your body continually kills more bacterial cells and hopefully completely eradicates the bacteria. If for some reason a person is unable to fight the bacteria their body will just continue to make more of the IgG antibodies.

[Mae6294]

I think I followed you. So if the virus is indeed one that can be out of your system without going into "hibernate" stage (same a simple head cold) the antibodies will go down or disappear for that virus, but if it is a virus that does "hibernate" (HPV or HIV) the antibody level changes depending on how much is in the system at time to activate B cells to an appropriate amount of antibodies needed to attack it. Killing some but forcing most of the virus(es) back into the "hibernate" stage?

Do you happen to know how long an IgG antibody will be an antibody before rearranging into something else for a while?

[Neuromedstudent]

I think it may all depend on the virus. Some viruses are latent and can sort of "hibernate" inside the host cell until and environmental change activates it in the cell. Positive IgG tests are a result of the antibodies present, it is not detecting the virus itself. Therefore you could have a virus for weeks and it not be detectable, for instance the HIV virus.

So...after the virus has been eradicated in it's active form, assuming it can be, the immune system does have B cells or memory cells which will identify the virus if it infiltrates the host in the future. This of course does not work for viruses that mutate at a rapid rate like influenza virus.

To answer the question...
The amount of anitbodies in the hosts "system" does go down to undetectable levels after awhile. Have you ever heard the saying, "my viral load is down today"? This also happens in people who are infected with HPV. They test postitive and then retest one year later and the test comes back negative. Though this may seem wonderful it's not really because most people dont understand they are still carriers of the virus and can still pass it on. Many people think they have been cured! This is not possible with HPV just as it is not with HIV, yet!

Good luck with your research. Hope this helped.