Generation of Retinal Pigment Epithelial Cells Derived from Human Embryonic Stem Cells Lacking Human Leukocyte Antigen Class I and II

Petrus-Reurer S. Winblad N., Kumar P., Gorchs L., Chrobok M., Kathleen Wagner A.K., Bartuma H., Lardner E., Aronsson M., Plaza Reye A., Andre H., Alici E., Kaipe H., Kvanta A., Lanner F.Stem Cell Reports, 2020

In this Stem Cell Reports article, the authors developed a strategy to evade the immune recognition triggered during transplants therapies with human embryonic stem cell-derived retinal pigment epithelial (hESC-RPE) cells. They generated and characterized hESCs and hESC-RPEs lacking surface presentation of HLA-I and -II through CRISPR/Cas9 targeting of B2M and CIITA. They established single-knockout beta-2 microglobulin (SKO-B2M), class II major histocompatibility complex transactivator (SKO-CIITA) and double-knockout (DKO) hESC lines that were further differentiated into corresponding hESC-RPE lines lacking either surface human leukocyte antigen class I (HLA-I) or HLA-II, or both. The activation of CD4+ and CD8+ T-cells was markedly lower by hESC-RPE DKO cells, while natural killer cell cytotoxic response was not increased. The results show that hESC-RPEs lacking HLA-I and -II evade T-cell response. Moreover, hESC-RPEs lacking HLA-I and -II do not increase NK cell cytotoxic activity. After transplantation of these immune-modified hESC-RPEs in a preclinical rabbit model, donor cell rejection was reduced and delayed. In conclusion, we have developed cell lines that lack both HLA-I and -II antigens, which evoke reduced T-cell responses in vitro together with reduced rejection in a large-eyed animal model. The results support the strategy to overcome host-donor mismatch in non-autologous cell-based treatment of AMD and other hESC-derived cell replacement therapies.