I wanted to take
the time to go over one of the questions that Dr. Cohen asked within the notes, I decided to answer this question above (in the title).
An antigen
is something that is recognized by the body and in return, it signals an immune
response referred to as an immunogen. For example, toxins,
bacteria, foreign blood cells etc. A tolerogen is something that
does NOT cause an immune response, but rather, prevents an immune response.
In order to be
able to change any antigen into a tolerogen, you first want it to be something with which the body will be able to function normally in the presence of it. But this is a hard thing, if something is already an antigen, it is technically already designated as a bad foreign thing, so I am not positive that it would be good for the body to function normally in the presence of any antigen turned tolerogen. Does this make sense?
However, one example of an
antigen that I think would greatly be of benefit if turned into a tolerogen is
an organ specific antigen. Each organ has its own particular antigen that
distinguishes it from any other organ. One thing though, that I am not sure of
is: is this antigen specific between that particular organ in question between
species, or is it specific to that particular organ within an individual? If it
is the latter I think that changing this organ specific antigen into a
tolerogen would be of great use in organ and tissue donation and it could
potentially decrease the number of rejections experienced by recipients of
those organs.
Deandra raises interesting points. I'd like to ask: what if something that is an antigen (immunogen) in most people, and was dangerous, got into your body, and for you, it turns out to be a tolerogen? Could that happen? Would it be good or bad for you?
ReplyDeleteThis is a very interesting idea, and got me thinking. To JJ Cohen, if something that is normally an antigen (in most people) but turned out to be a tolerogen in you, this could be good. For example, if you got infected with a flu virus strain but it didn't cause an immune response, you probably would not feel sick. You would probably live with this virus inside you, indefinitely? Is this what a carrier is? In this case it would be bad for the people around you. But if I am confused about what a tolerogen is, then the above senario could be bad because you would not make the approriate immune response to get rid of the invading virus. If the virus could still cause harm the cells of your body, this could be a real problem. So the answer to the question is fairly complex, I think?
ReplyDeleteI may not have a complete grasp on the concept of a tolerogen; however, in general, I assumed that it was, as Deandra pointed out, an antigen that does not cause an immune response. Thus, if the antigen that we are being exposed to is "dangerous", I feel that it would be harmful if our body did not produce an appropriate immune response to eliminate it. Based on the link below, it appears that the bacterium that causes leprosy, Mycobacterium leprae, can induce tolerance, which prevents the immune system from removing it (in patients with lepromatous type of leprosy).
ReplyDeletehttp://pathmicro.med.sc.edu/ghaffar/tolerance2000.htm
Courtney I beleive you hit it right on the nail and that you would be a carrier if you did not have an immune responce to something but you were infected to something. I think we talked about some type of bacteria in class, where JJ showed the agar plate of the nurses hand. I don't think it would necissarily be bad for you but it would depend what the pathogen is. There are many species that are vectors for certain diseases but they themselves are not affected by the disease or pathogen. Some examples that I could find of carriers where the host was not infected are Typhoi and EBV, which is Epstien-Barr virus, a member of the herpies family. In these cases humans can give in to other people but are not affected by the disease and it causes them no harm.
ReplyDeleteA question that comes to mind when reading this?
I know once you have chickenpocks it stays in your body, specifically in the brain, for life. In some older people the disease comes back as shingles under times of stress or and depressed immune system. Even though you are a carrier you are not infectious or transmiting the disease. Does this mean that this antigen is a tolerogen sometimes and not other times?
Chickenpox actually goes latent in the dorsal root ganglia of the spinal cord. It survives because herpes viruses (of which it is an example) are able to shut off almost all protein production and so the "fly beneath the radar." You aren't tolerant, you just can't see the antigens. But if something activates the virus, it is produced and runs down the axons to the skin; there, you get a terrible rash which is partly your Th1 cells attacking the virus-infected cells. Greta discussion, you guys!
ReplyDelete