If a transplanted organ's MHC cells don't match those of the recipient, What will happen?
1) The recipient's immune system will change the MHC markers on the organ so that it won't be identified as an intruder.
2) The recipient's immune system will identify the transplanted organ as an intruder and attack it.
3) The recipient's body will block off the new organ and it won't function normally.
4) The organ will change its MHC cells so as to be recognized by the recipient's immune system.