Extracellular vesicles as mediators of alloimmunity and their therapeutic potential in liver transplantation

Figure 2 Three pathways of allorecognition. Schematic illustration of the three major pathways of allorecognition: Direct, indirect, and semidirect. In the direct pathway, intact non-self major histocompatibility (MHC) Class I and Class II on donor antigen-presenting cells (APCs) activates CD8 and CD4 T cells respectively. In indirect recognition, recipient APCs present processed donor allogeneic peptides in the context of self-MHC to recipient T cells. In the semidirect pathway, recipient APCs are cross-dressed with donor MHC, acquired from donor-origin extracellular vesicles for instance, which upon encounter activates recipient T cells. Created with BioRender.com. APC: Antigen-presenting cell; MHC: Major histocompatibility; EV: Extracellular vesicle.