On guard before the first breath: the immune system is already at work before birth

The womb is about as protected as a place can be — which is why Pia Rantakari's team at the University of Turku was so surprised to find it garrisoned. Neutrophils, the white blood cells that rush first to any infection, turn out to be present in large numbers across developing tissues before birth, the team reports in Nature Communications. And they are not trainees: embryonic neutrophils swallow particles, release microbe-killing oxygen compounds and cast the same web-like traps adult cells use to snare invaders. 'What is the role of these defence cells when the embryo is still safely inside the uterus?' asks doctoral researcher Laura Lintukorpi. Part of the answer may be construction, not combat — many of the cells sit inside developing tissue itself, suggesting they help build the body as well as defend it.

SDG 9 · Industry, innovation and infrastructure — Mechanism: tech innovation