Different mechanisms by which MVs may interact with target cells. MVs may (1) stimulate target cells directly by surface-expressed ligands acting as a kind of “signaling complex”; (2) transfer surface receptors from one cell to another; (3) deliver proteins, mRNA, bioactive lipids, and even whole organelles (eg, mitochondria) into target cells; and, finally, (4) serve as a vehicle (“Trojan horse” mechanism) to transfer infectious particles between cells (eg, HIV or prions). In this issue of Blood, Martínez and colleagues describe that MVs derived from T lymphocytes express Hh morphogens that may induce megakaryopoietic differentiation in hematopoietic progenitors.