Molecular and cellular activities of Helicobacter pylori pathogenic factors

Stomach infection,vith pathogenic strains of Helicobacter pylori causes in some patients severe gastroduodenal diseases, These bacteria produce variou s virulence factors and, here, we review the recent acquisition on the bioc hemical mode of action of three major factors, We discuss the role of ureas e both as buffer of the stomach pH and as source of ammonia. The vacuolatin g toxin alters the endocytic pathway of non-polarized cells, inducing the r elease of acid hydrolases, the depression of extracellular ligand degradati on and of antigen processing and, in the presence of ammonia, smelling of l ate-prelysosomal compartments, In polarized epithelial monolayers, vacuolat ing toxin induces an increase of the paracellular permeability, independent of vacuolation, The neutrophil activating protein induces the production o f oxygen radicals in human neutrophils and could contribute to the damage o f the stomach mucosa, The activities of these factors are discussed in term s of the need of the bacterium of increasing the supply of nutrients from t he stomach lumen and from the mucosa, (C) 1999 Federation of European Bioch emical Societies.