If tumour cells manage to survive in the body over a longer period of time, the immune system will tolerate them as normal body tissue - although the tumour cells are dangerous. T lymphocytes usually destroy abnormal or infected cells. But once the tumour is perceived as normal they no longer attack the tumour cells. Physiological tolerance prevents self-attack (as in autoimmune diseases) but is counterproductive for the defence against cancer.

There is a clever method of overcoming the body’s tolerance against cancer cells. Some viruses infect only tumour cells without harming healthy cells. One of these viruses is the Newcastle Disease Virus (NDV). NDV is pathogenic to poultry but harmless for humans and does not lead to any detrimental effects on human health whatsoever.

The virus alters the infected tumour cells. As a result, they send so called danger signals. This helps the immune system to recognize these cells as dangerous and attack them. This method overrides immunologic tolerance towards tumour cells.

In our laboratory we are able to cultivate the NDV and infect tumour cells. This intelligent approach helps the immune system to distinguish tumour cells from healthy cells and subsequently destroy them.