What do we know about existing human embryonic stem cell derivations?
At the request of the Secretary of Health and Human Services, Tommy G. Thompson, the NIH has identified investigators from ten laboratories in the United States and around the world who reported that they had derived human embryonic stem cells from 64 individual, genetically diverse blastocysts. All of the existing cells reported to the NIH meet President Bush’s criteria. The scientists who developed these stem cells lines report that the cells are viable, show characteristic stem cell morphology, can be maintained frozen, as well as in culture, and have undergone at least several population doublings. The majority of these cells were reported to express all of the markers known to be associated with human embryonic stem cells, including stage specific embryonic antigens (SSEA-3 and SSEA-4), the enzyme, alkaline phosphatase, and tumor rejection antigen 1 (TRA-1-60 and TRA-1-81). The scientists reported to the NIH that the cells could be frozen and thawed and continue to grow while main
