Search and destroy! This image shows us how an immune cell, called a macrophage (orange), attacks foreign bodies like bacteria – or this microbead (purple) – completely engulfing it so it can be broken down deep within the cell. Molecules on the surface of foreign bodies signal danger to the macrophage cell, which attacks and swallows them. This helps keep the body free of infection – most of the time.
Imaged using scanning electron microscopy by Darren Brown, University of Queensland. This image has been colour enhanced.
Size: the bead is 3 micrometres across.