Comprehensive In Vitro Profiling Demonstrates Successful Immune Evasion of Bioengineered Immune-Shielded Heart Valves

Living donor valves for valve replacement in pediatric patients, come with the risk of immune rejection of the implanted tissue. To address this, and increase the options for living implants in pediatric patients, we previously developed a lentiviral immune-shielding strategy that leverages viral immune evasion mechanisms to downregulate surface HLA expression (via US2) and suppress natural killer (NK) cell activation (via Serpin b9). In this study, we comprehensively evaluated the impact of delivery of immune-shielding genes in donor valve cells and whole donor valves on immune responses in vitro using host peripheral blood mononuclear cells (PBMCs). Our results demonstrate that this approach prevents immune cell-mediated death of donor heart valve cells and reduces PBMC clustering around the allogeneic valve cells. Transcriptomic analysis of immune-shielded donor valves via bulk RNA sequencing revealed upregulation of genes associated with immune tolerance pathways commonly observed in viral infections, cancer, and placental development. These findings support the impact of immune-shielding technology as a strategy to protect allograft heart valves from immune-mediated degeneration, advancing the path toward durable, immunologically compatible implants for pediatric patients.