[krehl]

Can anybody explain why/how the resulting protein is recognized as foreign by the body? It is build using the same components and mechanisms as every other one, right? The body can't have a dictionary of 400.000 known proteins, can it?

[robbiep]

The full response here requires a deep dive into the immune system and self tolerance but basically, yeah, the immune system learns how to know what is ‘self’ and what is ‘else’. And this is specific to a person’s actual body (ie the reason someone develops organ rejection in the event of a transplant or can develop graft vs host disease in the event of a stem cell transplant (new immune system attacks body bc it isn’t ‘self’).

It’s really an amazing system