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

Human therapeutic cloning requires the reprogrammingof a somatic cellby nuclear transferto generate autologous totipotentstem cells. We have parthenogenetically activated 22 human eggs and also performed nuclear transferin 17 metaphaseII eggs. Cleavage beyond the eight-cell stagewas obtained in the parthenogenetic-activated eggs, and blastocoelecavities 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.