University of Leeds researchers, funded by Cancer Research UK, have used a library of DNA to create a vaccine that could be used to treat cancer, according to a study published in Nature Medicine.
Before now, 'gene therapy' vaccines have often delivered just one gene to stimulate the immune system. It produces a protein, called an antigen, which activates the immune system to destroy cancer cells.
It has been difficult to develop successful cancer vaccines because each tumour has specific proteins and identifying the right antigens has been a huge challenge.
Scientists have also tried to boost the effectiveness of vaccines by using several genes to increase the chances of producing successful antigens. But a worry has always been that the immune system's response would be too strong for the body to handle.
But now researchers, working with the Mayo Clinic in Rochester, US, have solved this problem in experiments involving mice.
The team used doses of a vaccine made from a virus which contained a 'library' of DNA, containing multiple fragments of genes and therefore many possible antigens. This approach did not send the immune system into overdrive, which had been a concern. Instead the range of DNA meant the vaccine was able to target the tumour through many routes.
Importantly, the DNA library was harvested from the same organ as the tumour. This meant that the immune system 'self-selected' the cancer antigens to respond to and did not react against other healthy parts of the body. Also, the process of self-selection was triggered when the vaccine was injected into the bloodstream, an approach to vaccination that is far more practical than injecting directly into tumours.
The researchers delivered a library of DNA taken from healthy prostate tissue in mice. When delivered in a virus, the vaccine successfully treated mice with prostate cancer.
University of Leeds' Professor Al
|Contact: Paula Gould|
University of Leeds