The initial attachment of pathogens (bacteria, viruses) to the intestinal wall is via epithelial cell surface sugars. 2’-FL has been shown to be structurally similar to these epithelial sugars, thereby functioning as a decoy receptor for pathogens7. In this way, 2’-FL can inhibit binding and infectivity of pathogens.
Adhesion of invading pathogens to human epithelial cells is a frequent first step in systemic infection. Researchers evaluated the ability of 2′-FL and 3-FL to inhibit such adhesion in vitro.9 Results demon strated that 2’-FL and 3-FL can inhibit adhesion of enteric and respiratory pathogens (including C. jejuni, enteropathogenic Escherichia coli, Salmonella enterica serova fyris and P. aeurginosa) to human epithelial cell lines. in a subsequent study, researchers were able to show that 2’-FL and 3-FL are able to block norovirus-like particles from binding to histo-blood group antigens in vitro, with data suggesting that these HMOs may mimic these anti gens, acting as naturally occurring decoys, and thus as antiviral agents against norovirus infection.10 Another study examined the in vitro effect of 2’-FL and three other oligosaccharides on the infectivity of human rotavirus strains in kidney epithelial cells from African green monkeys (MA104 cells). All oligosaccharides substantially reduced the infectivity of human rotaviruses, an effect that was attributed to interaction directly between the oligosaccharide and the virus.27
High levels of 2’-FL in breast milk have been shown to be protective against diarrhea associated with specific pathogens.8 More specifically, rates of C. jejuni diarrhea during breastfeeding were shown to be inversely associated with 2’-FL as a percentage of milk oligosaccharides. compared with infants fed milk with medium and high levels of 2’-FL, infants receiving milk with low levels of 2’-FL had significantly higher rates of Campylobacter diarrhea during breastfeeding. Overall, a significant inverse association was found between total 2-linked fucosylated oligosaccharides as a percent of HMO and rates of all moderate-to-severe diarrhea during breastfeeding.