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

Summary Human embryonic stem cell-derived retinal pigment epithelial (hESC-RPE) cells could serve as a replacement therapy in advanced stages of age-related macular degeneration. However, allogenic hESC-RPE transplants trigger immune rejection, supporting a strategy to evade their immune recognition. We 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. Activation of CD4+ and CD8+ T-cells was markedly lower by hESC-RPE DKO cells, while natural killer cell cytotoxic response was not increased. After transplantation of SKO-B2M, SKO-CIITA, or DKO 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.
Highlights • hESC-RPEs are immunosuppressive but can elicit T-cell and NK cell responses in vitro • hESC-RPEs lacking HLA-I and -II evade T-cell response • hESC-RPEs lacking HLA-I and -II do not increase NK cell cytotoxic activity • When xeno-transplanted, these immune-modified hESC-RPEs show reduced rejection
In this article, Lanner and colleagues show that retinal pigment epithelial cells derived from human embryonic stem cells are immunosuppressive, but still activate T and NK cells in vitro, and cause rapid rejection in a xenogeneic preclinical model. hESC-RPEs lacking HLA-I and -II neither activate T-cells nor increase NK cell cytotoxicity, and show reduced immune rejection after xeno-transplantation.