SUPERFICIAL COMPONENTS OF HEUCOBACI'ER PYWRI IN RELATION TO ADHERENCE TO EPITHELIAL CELLS

The presence of Helicobacter pylori in the human stomach has been highly associated with gastritis and peptic ulcer disease (1-4). Colonization of the mucus layer overlaying gastric tissue is a feature of H. pylori infection and is facilitated by the spiral shape and high motility of H. pylori (5). Adherence of H. pylori to gastric cells of infected patients has been directly observed, and may be important in the maintenance of infection (5-7). The attachment of H. pylori to gastric cells may involve bacterial components able to bind to cellular receptors. The cellular receptors may be restricted to the gastric cells which would explain the exclusive association of H. pylori with those cells, however the specificity of H. pylori for the gastric mucosa may also result from the particular microenvironment of the stomach. In the latter case, the cellular receptors binding H. pylori could be present on other human cells (8). It is thus of interest to study the colonization factors of H. pylori. Using the microscopic reference method (9,10) or microtiter adherence assays (11), all H. pylori strains studied have been found adherent to Hep2, INT407, YI or HeLa cells (8, 10). These observations support the hypothesis that the cellular receptor binding H. pylori is not restricted to gastric cells and can be studied using epithelial cell lines. Using methods that were developed for the study of colonization factors of Escherichia coli, Huang demonstrated hemagglutinating properties in H. pylori (12) and Evans described a fibrillar hemagglutinin binding on N-acetyl-neuraminyl-lactose, a receptor not restricted to the gastric cells (13). The N-acetyl-neuraminyl-lactose binding hemaglutinin is a putative adherence factor but other bacterial.components may be involved in the fixation of H. pylori to gastric cells. Supporting this hypothesis, a glyceroJipid unrelated to N-acetyl-neuraminyl-Iactose has been found to be another adherence receptor for H. pylori (14). Hypothesizing that colonization factors may be surface exposed we extensively studied the composition and the biologic activities of the H. pylori superficial material.