Chimeric Antigen Receptor T cells (CAR T) are comprised of an extracellular antigen recognition domain, intracellular T cell activation and co-stimulatory domains. These cells allow for potent and specific targeting of cancer cells, bypassing the need for antigen presentation and T cell receptor recognition. CAR T is mostly generated using lentiviral transduction of autologous T cells in conjunction with non-specific expansion in cell culture. CAR T-specific stimulation has been described using genetically engineered artificial antigen presenting cells (aAPCs). A strategy designed by Dr. Dean Lee and his team can select and expand any CAR T cell product in culture. This allows for safely infused exosomes and other membrane particles derived from aAPCs to also be envisioned as a pharmacologic, given to patients receiving CAR T to promote in vivo expansion and persistence of said cells. This approach could also be applied to antigen-specific TCR stimulation by modifying the aAPC to express the appropriate MCH-peptide as the antigen.