One of the most potent players within the immune system is the so-called ‘natural killer cell’. The ‘NK’ cell attacks by emptying sacks full of destructive proteins, known as lytic granules, across its membrane into a diseased cell, causing the target to dissolve. And, in research published today in PLoS Biology, molecular immunologists from Imperial College London caught it all on film using specialized microscopy technology.

In the video below (skip to 1:20), you can watch a natural killer cell assail a target cell. The movie shows the two cells layered on top of one another; their point of contact is indicated by the green-stained ring, composed of clusters of fluorescent receptors on the surface of the natural killer cell. The contact itself activates these receptors, which in turn recruit the red-stained lytic granules to the cell membrane. In the final act, these potent granules fuse with the target cell’s membrane, and empty their contents to kill it. Cue the credits.