Forever young by Alpha(diversity)ville: restricting intestinal microbiome maturation stunts immune system development and increases susceptibility to infection.

The microbiome is a keystone of adult gastrointestinal (GI) tract health, where it facilitates digestion, wards off pathogen colonization, and exerts a powerful influence on the physiological health of organs ranging from the brain to the kidneys. From its establishment at birth and through the initial years of childhood, the human microbiome is particularly dynamic, shifting in its composition and alpha (species) diversity to an adult profile as dietary sustenance transitions from milk-based sources to others such as solid food. An innovative study has now demonstrated how microbiome maturation is requisite both for the progression of immune system development and for long-term gut barrier function. These insights have significant ramifications for designing pediatric approaches to cultivate immune cell ontogeny in the formative stages of human infancy.