Figure 3

The interaction between the ESC/iPSC-derived cells and T cells in recipients. In addition to the engagement of the T-cell receptor (TCR) and the allogeneic or syngeneic major histocompatibility complex (MHC) containing self- or foreign peptides on the surface of ESC- or iPSC-derived cells, secondary activation pathways such as those involving the interaction of CD28 with B7 and CD40 with CD40L are also critical for T-cell activation. CTLA4 has higher binding affinity for CD28 and can effectively block the interaction between B7 and CD28, leading to the inhibition of T-cell activation.