Engineering of immune checkpoints B7-H3 and CD155 enhances immune compatibility of MHC-I^-/- iPSCs for β cell...

Induced pluripotent stem cells (iPSCs) represent a source from which β cells can be derived for diabetes replacement therapy. However, their application may be hindered by immune-mediated responses. Although abrogation of major histocompatibility complex class I (MHC-I) can address this issue, it may trigger natural killer (NK) cells through missing-self recognition mechanisms. By profiling the relevant NK-activating ligands on iPSCs during in vitro differentiation into pancreatic β cells, we find that they express high levels of B7-H3 and CD155. Hypothesizing that such surface ligands could be involved in the amplification of NK-activating signals following missing-self, we generate MHC-I-deprived B7-H3^-/-, CD155^-/-, and B7-H3^-/-/CD155^-/- iPSCs. All engineered lines correctly differentiate into insulin-secreting β cells and are protected from cell lysis mediated by CD16_dim and CD16⁺ NK subpopulations both in vitro and in vivo in NSG mice. Our data support targeted disruption of NK-activating ligands to enhance the transplant compatibility of MHC-I^-/- iPSC pancreatic derivatives.