Influence of soluble haemagglutinins on adherence of Helicobacter pylori to HEp-2 cells.

In a study of six laboratory strains of Helicobacter pylori, two different modes of bacterial adherence to HEp-2 cells were found. Electronmicroscopy revealed that strains known to possess soluble haemagglutinin adhered intimately to the cell surfaces, with cupping of the plasma membrane and coalescence of glycocalyces at sites of attachment. Strains of H. pylori without soluble haemagglutinin also attached, but did not induce membrane cupping or show glycocalyx fusion. Light microscopy did not distinguish between these patterns of adherence. Bacterial attachment was unaffected by pre-treatment of HEp-2 cells with neuraminidase. Exposure of the bacteria to trypsin or to colloidal bismuth subcitrate (CBS) before being added to HEp-2 cells markedly impaired bacterial adherence. This effect of CBS may contribute to the known efficacy of bismuth therapy in patients with H. pylori-related gastritis.