Scientists have discovered a protein which "turbo-charges" the immune system so that it could fight off any cancer or virus.

In a breakthrough described as a "game-changer" for cancer treatment, researchers at Imperial College London found a previously unknown molecule which boosts the body’s ability to fight off chronic illnesses.

The scientists are now developing a gene therapy based on the protein and hope to begin human trials in three years, in a release to Ghana News Agency said.

Professor Philip Ashton-Richkardt from the Section of Immunobiology in the Department of Medicine at Imperial College and lead author said “this is exciting because we have found a completely different way to use the immune system to fight cancer."

“It could be a game-changer for treating a number of different cancers and viruses.

“This is a completely unknown protein. Nobody had ever seen it before or was even aware that it existed. It looks and acts like no other protein.”

The protein – named Lymphocyte Expansion Molecule, or LEM, promotes the spread of cancer killing "T cells" by generating large amounts of energy.

Normally when the immune system detects cancer it goes into overdrive trying to fight the disease, flooding the body with T cells. But it quickly runs out of steam.

However, the new protein causes a massive energy boost which makes T cells in such great numbers that the cancer cannot fight them off.

It also causes a boost of immune memory cells which are able to recognise tumours and viruses they have encountered previously so there is less chance that they will return.

The team made the discovery while screening mice with genetic mutations.

They found one type produced ten times the number of cancer-fighting T cells, suppressing infections and becoming resistant to cancer.

Researchers found that the mice with enhanced immunity produced high levels of the unknown protein which is also found in humans.

They are hoping to produce a gene therapy whereby T cells of cancer patients could be enhanced with the protein and then injected back into the body. It could end the need for harsh chemotherapies as the body itself would be fighting the disease, rather than toxic drugs.