Natural killer cells for fighting cancer Natural killer (NK) cells are an important part of the innate immune system, helping to defend the body against tumours and infections. The NATURIMMUN project combines both fundamental and applied research into NK cells, work which could lead to effective new anticancer therapies, as Professor Erhard Hofer, the initiator of the project, explains A type of
lymphocyte, natural killer (NK) cells play a central role in the body’s defence against disease, helping to identify and destroy alien and infected cells. While NK cells are not homogenous, they share common features. “NK cells can do two main things. One is a kind of immune regulatory function, where they use certain cytokines to help activate other immune cells,” says Professor Hofer. “The second major function, which is especially important in terms of therapy, is that they can kill cells that they recognise as virally infected or abnormal, such as tumour cells.” These attributes make them powerful effectors to eradicate cancer, a prime motivation behind the work of the NATURIMMUN project, an EU-backed initiative which combines basic and applied research into NK cells. “We have assembled a combination of labs with different competencies from several countries that have contributed to NK cell research. This includes basic research, such as delineating the function of certain receptors on the surface of NK cells, and more clinicallyoriented research,” says Professor Hofer. “Indeed, we and others could demonstrate
safety and feasibility when infusing donor NK cells to leukemia patients after stem cell transplantation. However, limitations due to low cell numbers and tumor immune escape mechanisms still exist,” adds Professor Ulrike Köhl, the current coordinator of the project. The combination of basic and applied research is designed to help bridge the gap between academia and the commercial sector, and in turn to help translate research advances into improved treatment in the clinic. The foundation of the NATURIMMUN
which kills the tumour cells and the normal immune cells – after which patients receive a stem cell transplant from a donor. “These cells re-constitute a new immune system for the patient, that can then target leukemia cells,” explains Professor Hofer. “It has been shown that NK cells are an important component of the new immune system formed by the donor transplant, and are active in rejecting the leukemia cells.” Further, a number of clinical trials have been performed where donor NK cells,
NK cells are effective against cancer and NK cells prepared for infusions have been classified as ‘Advanced Therapy Medicinal products’ work is a deep understanding of both the immune system and the function of NK cells. “It is intriguing that viruses and tumor cells have developed mechanisms to subvert the immune system in order to avoid the NK cell response and we can learn counter-strategies from these,” says Professor Hofer.
Activating NK cells Standard leukemia therapy is to use chemotherapy or radiation treatment,
expanded and activated ex vivo, have been directly infused into patients, with promising anti-leukemia effects. The sideeffects have been found to be far less severe than with conventional treatment methods. Using an infusion of NK cells after a transplant also reduces the risk of graft versus host disease, a complication where the transplant itself reacts against the normal cells, which in severe cases can even lead to the death of the patient. “With NK cells adverse effects are very much less
Patients receiving infusion therapies..
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