A Killer Instinct

Protecting us from viruses, bacteria and other enemies requires a diverse skill set, and the immune system employs a number of different cell types to achieve this. Those responsible for the most rapid response are known as 'natural killer', or NK, cells, as they can detect diseased cells without having to recognise a specific marker of the agent causing the problem. Here, an NK cell (on the left) has come into contact with another cell, and is checking it for signs of viral infection or other stresses. If it spots an anomaly, it will release toxic molecules (in red) from specialised compartments, the cytotoxic granules; these will trigger apoptosis, the self-destruction of the target cell and any virus particles it contains. All this requires substantial rearrangements of the NK cell, both at its surface and within, and much remains to be learned about this critical process in our immune defences.

Written by Emmanuelle Briolat

Emmanuelle Briolat

Writer

A researcher specialising in visual signals in Lepidoptera, camouflage and the effects of light pollution, Emmanuelle’s writing covers a range of topics, from biomedical research to children’s books about moth defences.

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• Image by Image by Wellcome Image Award Finalists N. Dieckmann & N. Lawrence
• University of Cambridge, UK
• Copyright held by the Wellcome Trust
• Research published in Current Opinion in Cell Biology, February 2013