“Please don’t lyse me”: Programmed cell death ligand-1 expression on neonatal islet cells promotes xenotransplant acceptance

We read with great interest the article by Lei et al.1 Xenotransplantation offers promise in alleviating organ shortages; however, the substantial challenge of anti-pig T cell response hinders its clinical application. To this end, Lei et al1 investigated the engraftment and survival of porcine neonatal islet cells that expressed human programmed cell death ligand-1 (hPD-L1) in a humanized mouse model. The authors found that transgenic hPD-L1 on islet xenografts notably reduced the frequencies of interferon-gamma (IFN-γ)-expressing T cells, decreased graft-infiltrating immune cells, and promoted xenotransplant acceptance in recipients.