Specifically, the protective effect of B. infantis against the development of NEC has been attributed to decreased Toll-like receptor 2 (TLR2) and TLR4 expression, reduced intestinal inflammation as shown by reduction of TNFα and IL-8 production, and increased intestinal barrier function.38 Our data extend our current understanding to show specific B. infantis-induced reduction of enteric inflammation in healthy term infants in vivo, which suggest a critically important role for B. infantis in reducing and possibly preventing immune activation in the gut. This evidence concerns the gene TLR4 and necrotizing enterocolitis.