alloreactivity - (Oct/15/2011 )
BioMiha on Mon Oct 17 07:53:30 2011 said:
lucilius on Mon Oct 17 07:02:27 2011 said:
Do you know why the (or how) the body is able to limit the spread of the infection in the own tissue and not in the donor tissue?
Thanks a lot allready, I think I understand it now
In case of the graft there is no infection - there is no spreading. The cells of the graft synthesize the molecules by themselves and present them to the recipients immune system. And because all of the cells of the graft are foreign they are all targets for the CD8 cells.
Ok, I get this.
However, this makes me wonder the following thing: when there is an infection and thus spreading I would think that the immuneresponse would be bigger (since there is spreading, more cells get infected) so how come the body seems to be able to stop this spreading/infection and preventing to destroy the own tissue?
Lets take an example: imagine one of your muscles or perhaps kidney gets infected with an organisms: you will have then Tcells that start attacking this muscle or kidney, so how come our body is able to stop the complete destruction of this mucsle/kidney by the Tcells? (while if it is a donor kidney it gets killed)
(imagine that the kidney/muscle is completely infected , like it would have been a donor tissue with on almost every cell MHC molecules with foreign peptide. Or is this where I go wrong: isnt it possible for an entire piece of tissue to be infected and stops the immunesystem this infection fast so that not the entire tissue gets infected?)
-lucilius-
lucilius on Mon Oct 17 08:13:30 2011 said:
BioMiha on Mon Oct 17 07:53:30 2011 said:
lucilius on Mon Oct 17 07:02:27 2011 said:
Do you know why the (or how) the body is able to limit the spread of the infection in the own tissue and not in the donor tissue?
Thanks a lot allready, I think I understand it now
In case of the graft there is no infection - there is no spreading. The cells of the graft synthesize the molecules by themselves and present them to the recipients immune system. And because all of the cells of the graft are foreign they are all targets for the CD8 cells.
Ok, I get this.
However, this makes me wonder the following thing: when there is an infection and thus spreading I would think that the immuneresponse would be bigger (since there is spreading, more cells get infected) so how come the body seems to be able to stop this spreading/infection and preventing to destroy the own tissue?
Lets take an example: imagine one of your muscles or perhaps kidney gets infected with an organisms: you will have then Tcells that start attacking this muscle or kidney, so how come our body is able to stop the complete destruction of this mucsle/kidney by the Tcells? (while if it is a donor kidney it gets killed)
(imagine that the kidney/muscle is completely infected , like it would have been a donor tissue with on almost every cell MHC molecules with foreign peptide. Or is this where I go wrong: isnt it possible for an entire piece of tissue to be infected and stops the immunesystem this infection fast so that not the entire tissue gets infected?)
its simple:
Donor tissue: every cell has "strange" peptide in the MHC molecules.
Infecation: only infected cells have strange peptide ==> those will be attacked/killed. ===> if the infection is really big and if all the cells (or a majority of cells) are infected, then yes: the tissue can indeed be destroyed! So (theoretically speaking) if there is some sort of virus that is very very fast and infects an entire kidney then yes: the person risks losing his kidney.
But 99% of virusses/bacteria/parasites dont infect that fast, because if they did, they would commit "suicide"..
(you see what I mean?)
-pito-