Lactobacillus johnsonii Lal shares carbohydrate-binding specificities withseveral enteropathogenic bacteria

The carbohydrate-binding specificities of the probiotic lactic acid bacteri um Lactobacillus johnsonii La1 (a health-beneficial bacterial strain able t o be incorporated into the human intestinal microflora) were investigated i n vitro. First various soluble complex carbohydrates mere tested as potenti al inhibitors of the strain adhesion onto Caco-2 intestinal epithelial cell s, and then bacterial binding to glycolipids immobilized on TLC plates was probed. Two major carbohydrate-binding specificities of Lactobacillus johns onii La1 were identified. A first one for an Endo-H treated yeast cell wall mannoprotein carrying mainly O-linked oligomannosides, and a second one fo r the gangliotri- and gangliotetra-osylceramides (asialo-GM1). Similar carb ohydrate-binding specificities are known to be expressed on cell surface ad hesins of several enteropathogens, enabling them to adhere to the host gut mucose. These findings corroborate the hypothesis that selected probiotic b acterial strains could be able to compete with enteropathogens for the same carbohydrate receptors in the gut.