Immune cells from embryo stem cells

Canadian researchers have managed to turn mouse embryo stem cells (ES) cells) into immune cells in the laboratory, a development they say could help treat cancer and HIV (human immunodeficiency virus) patients. Researchers at the University of Toronto managed to coax the ES cells to grow into 'T-cells', which normally destroy infected or cancerous cells in the body. When transplanted into mice that have no immune system, the lab-grown cells made mature, working T-cells, say the scientists, who published their findings in the journal Nature Immunology.

ES cells are the body's 'master cells', capable of growing into any type of tissue. Scientists have previously converted mouse and human ES cells into blood, nerve and muscle cells in the laboratory, but this is the first time they have managed to grow working immune system cells. 'We're very excited', says team leader Juan Carlos Zuniga-Pflucker, who hopes that T-cells grown from human ES cells could one day be used to replace faulty or infected immune system cells. He speculates that HIV patients could even be given cells genetically enhanced to fight the virus. They could also be used to treat immune system disorders, in which the body's immune cells attack the patient's own tissues.

To grow the T-cells, the team identified a molecule called DL1 (delta-like ligand), which is essential in the production of the specialised cells. They then grew mouse ES cells on a layer of 'support cells', which supplied them with DL-1 and other nutrients. When transplanted into immune-deficient mice, the  T-cells were able to fight a mild virus infection. But Zuniga-Pflucker cautions that there is still 'lots to work out', adding 'I wouldn't want to give anyone false hope'.