HIGH-AFFINITY BINDING OF LAMININ BY HELICOBACTER-PYLORI - EVIDENCE FOR A LECTIN-LIKE INTERACTION

Laminin, the major glycoprotein of basement membranes, was shown to be bound by the human gastric pathogen Helicobacter pylori. Binding of I -125-laminin by strain 17874 was time-dependent, specific and saturabl e. Scatchard analysis of specific binding indicated about 2000 binding sites per cell with a dissociation constant of 8.5 pM. Treatment of t he cells by heat (80-degrees) and with proteolytic enzymes drastically reduced laminin binding, suggesting that the laminin receptors are su rface proteins. Some highly glycosylated glycoproteins inhibited lamin in binding by 50%. Furthermore, N-acetylneuraminyllactose decreased la minin binding by 70% and neuraminidase treatment of laminin by 50%, wh ile a recombinant B1 chain of laminin, containing high-mannose type ol igosaccharides, inhibited binding by only 25%. This suggests that term inal sialic acids on laminin compete for a specific sugar binding prot ein(s) on H. pylori cells.