Inside all of us is an army of cells called neutrophils, primed and ready to take out any invader, be it bacteria in a wound or viruses entering our airways. As the first line of defense for the immune system, neutrophils attack and call in reinforcements in a coordinated effort to prevent infection. “Neutrophils are the fastest immune cells in your body, able to migrate one cell length per minute,” said Carole Parent, PhD, of the University of Michigan (U-M) Medical School Department of Pharmacology and Cell and Developmental Biology. The rapid response of neutrophils to a site of invasion is made possible through a chemical messaging system called chemotaxis. New research from Dr. Parent and her colleagues at the U-M Medical School and the U-M Life Sciences Institute explains the precise and surprising way these chemicals are generated.