Kiwi scientists have revealed an unexpected role played by a white blood cell critical to ridding our bodies of infection and cancer.

The Natural Killer (NK) cell is a "vigilante" cell that's known for destroying invaders
and cancer cells through a process of "identity card" checking.

New research from a team at Otago University shows how violent vigilante NK
cells act as helper cells to start up the immune response.

Associate Professor Alex McLellan said these cells patrol the body and destroy abnormal cells, especially infected or cancer cells.

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NK cells closely examine the surface of all cells and look for molecules that are present on healthy cells.

"Certain molecules act like identity cards, and NK cell are vigilantes, ready to respond if they don't see an ID card on cells," McLellan said.

"During infections or with cancer, the absence of these molecules triggers the NK cells to destroy the cells."

McLellan and Dr Sarah Saunderson, who both work in Otago's Department of Microbiology and Immunology, have identified a new way that NK cells act during infections or cancer.

"A few years ago we showed that NK cells were required for the vaccination response against cancer," McLellan said.

Otago University Associate Professor Alex McLellan. Photo / Supplied
Otago University Associate Professor Alex McLellan. Photo / Supplied

The group has now recognised that NK cells enhance the ability of the immune system to recognise fragments of tumour cells released into the blood.

These fragments induced potent immune responses against cancer.

"Our new work shows that NK cells are absolutely critical for the immune activity of these cell fragments."

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These latest findings, just published in the Journal of Immunology, also explain how such potent immune responses arise against cell fragments.

"This work also reveals new ways that NK cells help the immune system, aside from in their rather violent vigilante role."

The group is currently looking at ways to improve NK cell function through living vaccines and growth factors to enhance the immune response to cancer.

Young researcher talks 'good' viruses

Bacteriophage are viruses that infect bacteria and, unlike antibiotics with a large host range, have specific hosts. Photo / 123RF
Bacteriophage are viruses that infect bacteria and, unlike antibiotics with a large host range, have specific hosts. Photo / 123RF

Meanwhile, a young Massey University researcher has won an academic X Factor-style competition by sharing the benefits of a "good" form of virus, known as bacteriophages.

Communicating her research on phage as an alternative treatment in an antibiotic-resistant future has seen Courtney Davies take the national title in the Masters Inter-University Challenge for the Three-Minute Thesis competition.

Davies won the contest with her quick-fire presentation at the national 3MT masters finals at Victoria University last week.

She is passionate about studying phage as she felt they offer the best hope to combat anti-microbial resistance, which is predicted to kill more people than cancer by 2050.

Phage are viruses that infect bacteria and, unlike antibiotics with a large host range, have specific hosts.

There are more of them on Earth than stars in the observable universe.

Her research, under the supervision of Dr Heather Hendrickson, challenged the idea that all viruses were bad for us.

There were different types of phage that could be commonly characterised by their types of tails, amongst other things.

"Phage are very small and can only be viewed under an electron microscope," Davies said.

"They can be around 100 nanometres in size.

"However, we look for phage presence through 'plaques' which are clearings of infection on bacterial agar plates."