Transplantation of human cells into Interleukin-2 receptor gamma gene knockout pigs under several conditions.

Introduction: Previously, we performed gene knockout (KO) of interleukin-2 receptor gamma () in porcine fetal fibroblasts using zinc finger nuclease-encoding mRNAs, subsequently generating KO pigs using these cells through somatic cell nuclear transfer. The KO pigs lacked a thymus and were deficient in T lymphocytes and natural killer cells, similar to human X-linked severe combined immunodeficiency (SCID) patients. The present study aimed to evaluate whether pigs can support the growth of xenografted human cells and have the potential to be an effective animal model.

Methods: The XY pigs used in this study were obtained by mating XX females with wild-type boars. This permitted the routine production of KO pigs via natural breeding without complicated somatic cell cloning procedures; therefore, a sufficient number of pigs could be prepared. We transplanted human HeLa S3 cells expressing the tandem dimer tomato into the ears and pancreas of KO pigs. Additionally, a newly developed method for the aseptic rearing of SCID pigs was used in case of necessity.

Results: Tumors from the transplanted cells quickly developed in all pigs and were verified by histology and immunohistochemistry. We also transplanted these cells into the pancreas of designated pathogen-free pigs housed in novel biocontainment facilities, and large tumors were confirmed.

Conclusions: KO pigs have the potential to become useful animal models in a variety of translational biology fields.