Nature's Nets

This image shows two immune cells known as neutrophils, magnified hundreds of times with a scanning electron microscope. First discovered more than a hundred years ago, they act as the first line of defence in the body, pumping out anti-microbial chemicals and swallowing up bacteria and viruses. But in 2004, high-powered microscopes revealed a third mode of attack: casting out a deadly net of DNA and protein fibres – shown spewing from the right-hand cell in this image – that catches and disarms invading bugs. Formally known as neutrophil extracellular traps (NETs), they form localised ‘cages’ that focus germ-fighting power in a small area and avoid causing damage to neighbouring healthy cells. Although this is a powerful infection-beating mechanism, it’s not so good for the neutrophil. Because forming a NET requires the cell to throw out all its DNA – containing all the genetic instructions for life – it dies in the process.

Written by Kat Arney

Kat Arney

Writer

Dr Kat Arney is an award-winning science writer, broadcaster and public speaker, and is the founder and Creative Director of First Create The Media.

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• Image by Stavros Giaglis
• This image is a finalist in the International Images for Science 2016 exhibition, organised by the Royal Photographic Society and supported by Siemens as part of the Curiosity Project
• Image copyright held by the photographer