In the context of COVID-19, why is it possible to inject someone else’s antibody protein into a person without fear of stimulating an immune response. Does this indicate that, somehow, antibody conformation is universal?
Or rather ...
The immune system must differentiate between cellular and fragmentary material? It will attack any cellular material it deems ‘non-self’. But if foreign non-cellular material enters the body, such as dust, pollen etcetera we are in the realm of an allergic response. The allergic response is not absolute: only certain materials will cause a reaction.
So perhaps foreign protein, such as donor plasma products, are treated as potential allergens which, happily, do not cause an immune response; unlike midge spittle?