MHC II gene knockout in tissue engineering may prevent immune rejection of transplants.

The repair and reconstruction of tissue defects and organ loss are severe problems, and many patients are eager to find avenues to these matters. Up until now, the number of methods used to repair tissue defects has increased, but all of these have their own advantages and inconveniences, and do not seem to have been optimized. The development of tissue engineering offers new hopes to patients with tissue defects. To regenerate tissues and organs, we first need a source of seed cells. However, the sources of autologous cells are restricted, cell number is small, and xenogenic cells result in immunological rejections. Major histocompatibility complex (MHC) polymorphism is a key factor in tissue grafts. MHC II, in particular, is associated with allogeneic transplantation. We hypothesize that if we knock-out the MHC II gene of mesenchymal stem cells (MSCs) in vitro, these cells would not express MHC II molecules, and rejection problems will be solved. Accordingly, the industrialization of tissue engineering will be feasible, and products of tissue engineering will be utilized widely for any clinical treatments.