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.

人类胚胎干细胞来源的视网膜色素上皮细胞（hESC-RPE）可以作为老年性黄斑变性晚期的替代疗法。然而，同种异体hESC-RPE移植引发免疫排斥反应，支持逃避其免疫识别的策略。我们建立了单敲除的β-2微球蛋白（SKO-B2M），II类主要组织相容性复合物反式激活因子（SKO-CIITA）和双敲除（DKO）的hESC系，它们进一步分化为相应的缺少任何一种表面人类白细胞的hESC-RPE系I类抗原（HLA-I）或HLA-II，或两者兼而有之。hESC-RPE DKO细胞可显着降低CD4 +和CD8 + T细胞的活化，而自然杀伤细胞的细胞毒性反应不会增加。在临床前兔模型中移植SKO-B2M，SKO-CIITA或DKO hESC-RPEs之后，供体细胞排斥反应减少并延迟。总之，我们已经开发了既缺乏HLA-I和-II抗原又能引起T细胞反应减少的细胞系大眼动物模型中的体外排斥反应减少。