|Questions About Lectins|
Lectins and Mother's Milk
Safe as mother's milk: carbohydrates as future anti-adhesion drugs for bacterial diseases.
Glycoconj J 2000 Jul-Sep;17(7-9):659-64
Sharon N, Ofek I.
The majority of infectious diseases are initiated by adhesion of pathogenic organisms to the tissues of the host. In many cases, this adhesion is mediated by lectins present on the surface of the infectious organism that bind to complementary carbohydrates on the surface of the host tissues. Lectin-deficient mutants often lack ability to initiate infection. Soluble carbohydrates recognized by the bacterial lectins block the adhesion of the bacteria to animal cells in vitro. Moreover, they have also been shown to protect against experimental infection by lectin-carrying bacteria in different organs of mammals such as mice, rabbits, calves and monkeys. Although the high cost of production of the required oligosaccharides is falling with the recent introduction of enzymatic methods of synthesis, new technologies, in particular the use of engineered bacteria, promise to lower it even further. Attachment of the oligosaccharides to soluble polymeric carriers will increase greatly their effectiveness as antiadhesion agents. There is no doubt that anti-adhesive oligosaccharides will in the near future join the arsenal of drugs for the therapy of bacterial diseases.
Human milk is laden with glycoconjugates and amino sugars (for example, we as a species have the highest concentration of fucose in our milk, versus other mammals) Historically, the suspected role of these carbohydrates was to act as a 'prebiotic,' conditioning the growth of the gut bacteria. Evidence now is growing that they in fact act as anti-adhesion molecules, blocking the attachment of harmful bacteria by flooding their lectin receptors with decoy molecules. The high fucose content probably serves to block Candida yeast attachment (Candida uses a fucose-secific lectin to attack its host.)