Emerging novel virulence factors of Helicobacter pylori

Abstract

Through the expression of a wide range of differently functioning virulence factors, Helicobacter pylori possesses multiple possibilities to interact with host target cells that in combination determine the development and progress of diseases. Prominent H. pylori factors such as the type IV secretion system (T4SS), cytotoxin-associated gene A (CagA), vacuolating cytotoxin A (VacA), and blood-group antigen-binding adhesin (BabA)/sialic acid-binding adhesin (SabA) are discussed in other chapters. Besides those well-established pathogenic and virulence factors, a series of other bacterial factors exist, including neutrophil-activating protein (NapA), γ-glutamyl transpeptidase (GGT), tumor necrosis factor-alpha-inducing protein alpha (Tip), the cell-translocating serine/threonine kinase (CtkA), and bacterial proteases, such as the serine protease high-temperature requirement A (HtrA) or the collagenase Hp0169. These factors are described as secreted H. pylori proteins that might be implicated in pathogenesis as well. As additional novel disease-associated factors, the Helicobacter outer membrane proteins (Hop) HopQ and HopZ and the duodenal ulcer-promoting gene A (DupA) are also currently under intensive investigation. Since these H. pylori factors are either secreted or surface exposed, they can directly interfere with host cell functions to modulate cellular responses. Research on these bacterial structures is still at the beginning; however, they represent novel target molecules for supporting therapeutic intervention strategies.