Figure 1: Undifferentiated iPSCs derived by LV or genome-integration-free strategies are rejected in syngeneic recipients.

LV or minicircle-derived iPSCs expressing GFP and luciferase were injected intramuscularly in syngeneic or immunodeficient recipients, and their survival was monitored in vivo by bioluminescence imaging (BLI). (a) Representative BLI from one mouse per group demonstrating the longitudinal survival of minicircle- and LV-derived iPSCs in syngeneic and immunodeficient recipients. (b) Mean±s.e.m. bioluminescence of minicircle- versus LV-derived iPSCs in syngeneic and immunodeficient recipients demonstrating a progressive decay in bioluminescence to background levels by 42 days following implantation. After complete decay of bioluminescence signal, mice received a second injection of iPSCs. (c,d) Bioluminescence of iPSCs implanted in primed animals (2nd) had an accelerated decay compared with those receiving the first cell injection (1st). Data are representative of at least 10 animals and 3 independent experiments.