Somatic Cell Nuclear Transfer in Humans: Pronuclear and Early Embryonic Development

Human therapeutic cloning requires the reprogramming of a somatic cell by nuclear transfer to generate autologous totipotent stem cells. We have parthenogenetically activated 22 human eggs and also performed nuclear transfer in 17 metaphase II eggs. Cleavage beyond the eight-cell stage was obtained in the parthenogenetic-activate d eggs, and blastocoele cavities were observed in six. Three somatic cell-derived embryos developed beyond the pronuclear stage up to the six-cell stage. The ability to create autologous embryos represents the first step towards generating immune-compatible stem cells that could be used to overcome the problem of immune rejection in regenerative medicine.