Establishment and manipulation of monkey and human embryonic stem cell lines for biomedical research

We have established several embryonic stem (ES) cell lines of the cynomolgus monkey. They maintain the normal karyotype and pluripotency in culture for long periods. We obtained government approval and grants to produce human ES cell lines from frozen surplus embryos in April 2002. We have established and characterized three human ES cell lines (KhES-1, KhES-2, KhES-3). We started distribution of human ES cells to other research groups in March 2004. It would be important to produce genetically modified monkey and human ES cells for various purposes. After improvement of the transfection and selection methods, we have produced monkey ES cells with integrated transgenes at efficient and reliable rates. We are also investigating reprogramming of somatic cells into pluripotent stem cells by cell fusion with ES cells. Such reprogramming could be used to produce pluripotent stem cells for each patient without therapeutic cloning, which would raise ethical concerns.