A way to turn embryonic stem cells into the cells at the heart of the immune system raises the prospect of new cancer therapies and improved transplant technology.
Paul Fairchild, Herman Waldman, Richard Gardner and colleagues at Oxford University are the first to reliably and efficiently grow large quantities of healthy, functional dendritic cells from embryonic stem cells in the laboratory. This opens up the possibility of their genetic manipulation.
Their work, published in the latest issue of the journal Current Biology , gives researchers a powerful way to explore the biology of the immune system by bringing together two of the most exciting areas of medical research.
"This unites recent advances in stem cell biology and immunology - we have the enormous potential of both fields in the one system," said Fairchild.
Dendritic cells orchestrate the body's response to infection, driving the immune system by prompting killer T-cells to attack certain targets.
A full understanding of how they work could bring about a host of therapies.
However, it has proved difficult to reveal the function of the genes that give dendritic cells their capabilities because they have proved highly resistant to genetic modification.
By contrast, embryonic stem-cells - cells that can develop into every other type of cell - can easily be genetically manipulated.
By directing their differentiation into dendritic cells, Fairchild has devised a technique that allows scientists to systematically explore the genetics of this essential element of the immune system for the first time.
As proof principle, his team was able to attach marker genes to embryonic stem cells in the laboratory. They then treated the cells with a mixture of proteins to direct them to become dendritic cells.
These were grown in large quantities. The cells were found to carry the marker gene while retaining the remarkable abilities that allow them to direct the immune system within a living creature.
In the future, drugs could be produced from the insights Fairchild's method gives, which would boost the immune response to fight cancers or other diseases such as Aids.
Alternatively, they could dampen the immune response to stop the body rejecting transplanted organs and tissue.
The recent parliamentary vote to allow scientists to derive human embryonic stem cells from embryos will make the development of human therapies from this work far simpler.