Highlights•In utero microbial stimulation modulates both prenatal and postnatal immune cell
development.•Unique neonatal gut microenvironment allows for progressive colonization of …

The mucosal immune system of neonates goes through successive, non-redundant phases
that support the developmental needs of the infant and ultimately establish immune …

Neonates are highly susceptible to infection with enteric pathogens, but the underlying
mechanisms are not resolved. We show that neonatal chick colonization with Salmonella …

Alterations in enteric microbiota are associated with several highly prevalent immune-
mediated and metabolic diseases,–, and experiments involving faecal transplants have …

The existence of a neonatal window was first highlighted by epidemiological studies that
revealed the particular importance of this early time in life for the susceptibility to immune …

Highlights•IEC invasion is a crucial step in the life cycle of non-typhoidal Salmonella.•TTSS-
1 effectors SopE/E2 and particularly SipA mediate IEC invasion in mice.•Entry structures …

Rapid development of the fetal and neonatal intestine is required to meet the growth
requirements of early life and form a protective barrier against external insults encountered …

The intricate host–microbial interaction and the overwhelming complexity of the mucosal
immune system in the adult host raise the question of how this system is initially established …

Salmonella enterica serovars are associated with an estimated 1 million deaths annually
and are also useful model organisms for investigating the mechanisms of host–bacterium …

Although largely deprived from exogenous stimuli in utero, the mucosal barriers of the
neonate after birth are bombarded by environmental, nutritional, and microbial exposures …