human embryonic stem cells can produce natural killer Tcells to kill cancer cells

Here I go again:





Cancer-Fighting NK Cells Derived From Human Embryonic Stem Cells


By Anne Harding

NEW YORK (Reuters Health) Oct 26 - For the first time, researchers have derived natural killer (NK) cells with cancer-fighting potential from human embryonic stem cells (hESCs).

The hESC-derived NK cells destroyed human tumor cells in a series of in vitro tests, through direct cell-mediated cytotoxicity and by antibody-dependent cellular cytotoxicity, Dr. Dan S. Kaufman of the University of Minnesota Stem Cell Institute in Minneapolis and colleagues report in the October 15th issue of the Journal of Immunology.

The findings suggest that hESCs' therapeutic potential extends beyond using them to replace degenerated or dead cells, as in Parkinson's disease or diabetes, Dr. Kaufman noted in an interview with Reuters Health. "I think this really is an important possible direction for this work as well," he said.

Using a two-step process, he and his colleagues generated NK cells from CD56+ and CD45+ hESCs. The NK cells they produced expressed the same array of activating and inhibitory markers seen in mature NK cells, and could also be induced to produce cytokines. Tests with human tumor cell lines demonstrated that the new NK cells were able to kill them both directly and in an antibody-mediated fashion.

"Not only did they express all these right markers, they function like we think natural killer cells should function," Dr. Kaufman said.

The current study was performed using two federally approved hESC lines, he added. For clinical purposes, Dr. Kaufman said, it would be preferable to produce therapeutic NK cells from new lines.

These lines could avoid the potential risk of contamination currently approved lines carry, given that they were cultured on mouse feeder cells, he explained. New lines could also allow the development of a panel of NK cells with different capacities.

Dr. Kaufman said he and his colleagues are now gearing up for animal tests of the hESC-derived NK cells.

J Immunol 2005;175:5095-5103.