ABOVE: A pseudocolored scanning electron micrograph of a 14-week-old human fetal intestine
THET TUN AUNG AND BENOIT MALLERET, NUS YONG LOO LIN SCHOOL OF MEDICINE
Update (November 24): In a letter to Cell published today, a group of researchers argues that Ginhoux and colleagues' study did not adequately control for the possibility of contamination of samples, and that better-designed studies have found no evidence that fetuses are colonized with microbes. The study authors defend their methods in a separate letter published today.
Over the last decade, scientists have shown that the fetal immune system comes online much sooner than was initially thought, but what type of antigens train nascent immune cells and how this affects subsequent development remain open questions. In a study published June 1 in Cell, researchers determined that second-trimester human fetuses harbor live bacteria in tissues all over their bodies that can activate fetal T cells.
“What is ...
