Cancer fighting human immune cells to be grown in pigs

[Rich66]

Cancer fighting human immune cells to be grown in pigs


By Richard Alleyne, Science Correspondent

Last Updated: 6:01pm BST 15/10/2008

Cancer patients could have immune cells removed and cultivated in piglets before being injected back into them to boost the body's natural defences, new research claims. Scientists have long been excited by the prospect of 'turbo-charging' patients immune systems by injecting them with their own cancer fighting cells grown outside the body.But the process of cloning the immune or T- cells is extremely expensive and difficult for all but a few patients.Now the researchers believe pigs could hold the answer. They have successfully injected human cells into developing pig foetuses and found that they multiplied and matured as the pig grew.The new stem cells, which would then be implanted back into the patient, could even be modified in the piglet so as to boost their disease fighting powers, experts believe. They said the new system could mark a major breakthrough in the process which is known as cell transfer immunotherapy or T-cell treatment. The new research, detailed in New Scientist, was undertaken by Jeffrey Platt at the University of Michigan, Ann Arbor. To see if growing a human immune system inside pigs is possible, Dr Platt and his colleagues extracted stem cells from human umbilical cord blood and bone marrow, and injected them into developing pig foetuses. Lacking a mature immune system, the foetuses accepted the foreign tissue as their own, and when the piglets were born the injected cells had multiplied and matured into a diverse range of human T-cells, alongside the pig's own immune cells. The team were then able to extract the T-cells and while they have yet to re-introduce them to humans they have tested them to see if they are active and safe. The researchers separated out the human cells from the pig's blood and mixed some of them with ordinary cells from the person whose cells had been injected into the foetus. The extracted cells did not mount an immune attack, indicating that it should be possible to implant them back into the donor, but they did attack cells from other people, showing they were functional. Dr Platt believes the cells reared in the piglets are so young they could even be modified to fight specific diseases. "If I had HIV, I could put my stem cells in pigs and immunise them with an HIV vaccine," said Dr Platt. "You would get immunity in the pig that you would never get in my body." Dr Platt, who believes miniature varieties of pigs would be the most efficient way to cultivate cells, now wants to persuade the regulatory authorities to allow testing in humans. Immunotherapy is thought to work because usually there are too few of the cells naturally in a patient's body to fight cancer effectively but by boosting them, it boosts natural defences. In its most successful use to date one American patient suffering from advanced skin cancer even made a full recovery following the treatment. This was even though the disease had already spread to the lymph nodes and lungs. The new techniques raise the hope of fighting the disease, which claims 150,000 lives in Britain every year.