The public reaction to controversial events can be hard to anticipate. The cloning of Dolly the sheep caused a flurry of attempts to ban human cloning, pronouncements from President Clinton and other international leaders, and the creation of the National Bioethics Advisory Commission.

But the isolation of human embryonic stem cells so far has met with a more muted response despite the fact that it has crossed the species line into human territory. Instead, the loudest cries have been from NIH researchers frustrated that they are banned by federal law from doing similar work.

The stem cell advance, published last week by University of Wisconsin researchers in Science, involved the isolation and long-term culture of human embryonic stem (ES) cells derived from in vitro fertilized human embryos (see BioCentury Extra, Nov. 6).

In theory, the finding could lead to the development of immortal cell lines capable of being genetically engineered and able to differentiate into any type of tissue.

But having human ES cells in hand also could make human cloning more technically feasible, along with genetic engineering of human embryos and generation of human/animal chimeric embryos. In addition, critics may have objections to using cells derived from fertilized human embryos.

The technology, along with work on human embryonic germ (GS) cells done at Johns Hopkins University, is exclusively licensed to Geron Corp. (GERN, Menlo Park, Calif.).

NIH frustration

While GERN is funding the human stem cell research by its licensors, public funding agencies have stayed away from the field due to statutory barriers to funding research derived from human embryos.