system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5 How does a Body's immune system eventually recognize a donor organ as a part of it instead of a foreign entity?
gpt
Oftentimes, it never does. The body's immune system will continuously recognise the transplanted tissue as foreign, due to the immune system not being able to identify the proteins on the cells as its own. People who have had organ transplants often have to take drugs to suppress the immune system for life, as otherwise the immune system would destroy the donated organ.