Real-Time Bioluminescence Imaging of Macroencapsulated Fibroblasts Reveals Allograft Protection in Rhesus Monkeys (Macaca mulatta)

Background. Encapsulation of cells has the potential to eliminate the need for immunosuppression for cellular transplantation. Recently, the TheraCyte device was shown to provide long-term immunoprotection of murine islets in a mouse model of diabetes. In this report, translational studies were undertaken using skin fibroblasts from an unrelated rhesus monkey donor that were transduced with an HIV-1-derived lentiviral vector expressing firefly luciferase permitting the use of bioluminescence imaging (BLI) to monitor cell survival over time and in a noninvasive manner. Methods. Encapsulated cells were transplanted subcutaneously (n=2), or cells were injected without encapsulation (n=1) and outcomes compared. BLI was performed to monitor cell survival. Results. The BLI signal from the encapsulated cells remained robust postinsertion and in one animal persisted for up to 1 year. In contrast, the control animal that received unencapsulated cells exhibited a complete loss of cell signal within 14 days. Conclusions. These data demonstrate that TheraCyte encapsulation of allogeneic cells provides robust immune protection in transplanted rhesus monkeys.