Fig. 7: In vitro immunological blood tests after CIITA^+/+ or CIITA^-/- miPSC-RPE cell transplantation.

a The LGIR test of HM-22 monkey who received wild-type CIITA^+/+ transplantation and showed slight rejection was performed by co-culture of its PBMC (collected 12 weeks after transplantation) with CIITA^+/+ or CIITA^-/- miPSC-RPE. Allogenic monkey B95-8 B cells were used instead of RPE cells as a positive control (PC). The LGIR test with CIITA^+/+ miPSC-RPE but not with CIITA^-/- miPSC-RPE showed increase in CD8⁺/Ki-67⁺ (proliferative cytotoxic T cells), CD11b⁺/Ki-67⁺ (proliferative monocytes), and NKG2A⁺/Ki-67⁺ (proliferative NK cells) compared to PBMC only (no RPE). b The LGIR test of HM-24 monkey who received CIITA^-/- (MHC-II knockout) transplantation was performed as in (a) with PBMC collected 8 weeks after transplantation. By either CIITA^+/+ or CIITA^-/- miPSC-RPE, the proliferation of immune cells (CD4⁺, CD8⁺, CD11b⁺, and NKG2A⁺ cells) did not increase. Numbers (%) indicate double-positive cells. c The LGIR test of TLHM6 who had shown severe immune rejection after RPE cell transplantation in our previous study³¹ was performed as in (a). The LGIR test with CIITA^+/+ miPSC-RPE but not with CIITA^-/- miPSC-RPE showed a significant increase in proliferative CD4⁺ T cells. The plots on the left (X-axis: FSC, Y-axis: SSC) was used to define the gate according to our preliminary study to include the population of resting and proliferating lymphocytes. Statistical analyses of three independent experiments are shown on the right panel. *P < 0.0005, **P < 0.0001. N = 3 independent experiments; degree of freedom = 2; paired t-test; two-sided; PBMC only vs PBMC + WT RPE: P = 8.52635E-05 (t-value = −108.290584); PBMC + WT RPE vs PBMC + CIITA-KO RPE: P = 0.000371324 (t-value = 51.88027148).