The unambiguous mechanism of the antigen transfer is still unknown. However, there are three possible ways: I. acquisition of mTEC apoptotic bodies, which could possibly be related with low mTEC lifespan II. acquisition of exosomes and III. acquisition via trogocytosis, how antigen transfer can be mediated.
There is also an evidence, that antigen transfer and therefore indirect presentation by thymic DCs are regulated by PGE activator Aire.