Effect of mIL-10 immunomodulation on the viability of HEMA-MMA microencapsulated cells in vivo: Assessment by a non-destructive method

Microencapsulation of cells in a polymer membrane has been proposed as a vehicle for the delivery of therapeutic biomolecules. Prior to encapsulation, CHO cells were engineered to express murine Interleukin-10 (mIL-10) and a firefly bioluminescence protein, luciferase, which allowed for non-invasive tracking of transplanted cells in vivo with the Xenogen IVIS Imaging System. Successful short-term modulation of the transplantation site microenvironment with mIL-10 secreted from within capsules was demonstrated at Days 10 and 21. At the rate produced by encapsulated cells, the murine Interleukin-10 did not cause long-term xenogeneic graft tolerance by the mouse host. As the cells within capsules began to die the reduced levels of secreted mIL-10 were likely insufficient to continue modulating the immune system, at least with cell viability as a marker. The accumulation of host cells around the implant likely contributed to the initial cell death due to nutrient or oxygen deficiency.