Oligosaccharides and glycoconjugates of human milk could protect breast-fed infants against norovirus intestinal infections

Background: Noroviruses are, after rotaviruses, the most common cause of nonbacterial intestinal infections in children. It has been observed a lower incidence of norovirus gastroenteritis in breast-fed compared to formula-fed infants. Effective vaccines against noroviruses are not yet available, enhancing the interest of the protective mechanisms elicited by human milk. Human milk contains a wide range of agents that may play a role in the protection of breastfed babies against different conditions. There is an increasing interest regarding the role of oligosaccharides and glycoconjugates of human milk as bioactive agents that could protect against norovirus intestinal infections in children. Aim: The aim of our study was to review the current knowledge regarding the involvement of oligosaccharides and glycoconjugates in the protective properties that human milk elicits against norovirus intestinal infections. Methods: Scientific literature was analyzed using the pubmed.gov web browser. No restrictions to the year of publications were included. The terms searched were norovirus, oligosaccharides and glycoconjugates of human milk. Results: An outstanding role has been attributed to oligosaccharides and glycoconjugates of human milk in the defense against norovirus. Oligosaccharides and glycoconjugates of human milk show a structural resemblance to histo-blood group antigens that act as receptors of noroviruses in enterocytes. Therefore, they could act as decoy receptors and interfere the binding of noroviruses to their receptors, critical step to allow their infectivity. Conclusions: Human milk constitutes an unmatched supply of essential protective substances for the infant. Oligosaccharides and glycoconjugates of human milk could be the agents responsible for the protection of breast-fed infants against norovirus intestinal infections.