York: New role for natural killer cells

Research lead

Scientists at York University in the UK have discovered a new role for natural killer (NK) white blood cells, which they say could lead to improved treatments for chronic infections and cancer.

NK cells are abundant white blood cells that were recognised over 30 years ago as being able to kill cancer cells in vitro. Since then, their role in activating other white blood cells, including T lymphocytes and phagocytes, and in directing how the immune system responds to a wide range of infections has been established.

As a result they are widely regarded as being central to immune system against cancer and infection, and methods to increase the activity of NK cells underpin a range of experimental anti-cancer and anti-infective drugs.

Now a research team in the university’s Centre for Immunology and Infection led by Paul Kaye, has now demonstrated that NK cells also generate cytokines that inhibit immune responses. In an animal model of the tropical disease visceral leishmaniasis, too many NK cells can actually make the disease worse because they produce the anti-inflammatory cytokine interleukin-10, which can counteract many of the otherwise beneficial effects of these cells.

Kaye noted that other researchers have suggested in the past that NK cells might not always act favourably. “Now [we] have the first direct evidence that this can actually be the case. Although we have worked on an infectious disease, the same is likely to be true for NK cells in cancer. So, in practical terms, it means that we need to consider more carefully exactly how we use therapies that affect NK cells, to maximise their beneficial role.”

The new findings open up the potential of developing new drugs that specifically target the beneficial properties of NK cells in responding to infection and inactivate their anti-inflammatory effects. Conversely, in autoimmune diseases it may be possible to upregulate the production of IL-10, to reduce inflammation.