Bullet Time

Trained assassins swarm through our body, on the lookout for any unwelcome invaders. These specialised cells of our immune system are on the constant lookout for trouble, and have lethal techniques to see it off, but how do they make sure they only pick a fight with dangerous invaders, not our own healthy cells or helpful members of our personal microbiome? Keen to understand the details of how our immune system works so they can exploit it for new treatments such as cancer immunotherapy, researchers filmed one particular part: the membrane attack complex (MAC). The researchers watched as MACs assemble and fire deadly bullet holes in the skins of threatening cells over time (shown in the video), and saw that the process pauses, allowing potential victims one last chance to prove they're harmless by displaying a particular protein, before striking a killing blow to those that can’t prove their allegiance.

Written by Anthony Lewis

Anthony Lewis

Writer

Ant was the web editor in the early days of BPoD, and has since worked with the UK’s top science organisations as a writer and multimedia producer. He now splits his time between freelance work and managing multimedia at The Lancet.

Website

• Video adapted from work by Edward S. Parsons and colleagues
• London Centre for Nanotechnology, University College London, London, UK
• Video originally published under a Creative Commons Licence (BY 4.0)
• Published in Nature Communications, May 2019