File:Proposed pathways of interaction between transplanted hESC derivatives and the immune system continued..jpg

English: (C). Natural killer (NK) cell activation is controlled by integration of signals from activatory and inhibitory receptors. Inhibitory NK cell receptors recognize self-MHC-I molecules that restrain their activation (left). When unimpeded by the inhibitory receptors, binding of NK cell activation receptors to their ligands on target cells results in NK cell stimulation (right). (D) As most differentiated hESCs do not express co-stimulatory molecules (right) they may be protected from direct allorecognition (but their antigens can presumably initiate chronic immune responses through the indirect pathway). When MHC-I expression is low and lysis ligands are absent, hESC derivatives may be protected from NK-cell response (left). Cardiomyocytes derived from hESCs could potentially be used for restoration of heart functions (center). TCR T cell receptor.