Biologists have discovered an effective strategy that could prevent the human immune system from rejecting the grafts derived from human embryonic stem cells a major problem now limiting the development of human stem cell therapies. The discovery by UC San Diego researchers may also provide scientists with a better understanding of how tumors evade the human immune system when they spread throughout the body. The study by a collaboration that included scientists from China was enabled by the development of 'humanized' laboratory mice that contained a functional human immune system capable of mounting a vigorous immune rejection of foreign cells
