ABSTRACT
Helicobacter pylori are a primary cause of chronic gastritis and a factor in peptic ulcer disease. A variety of enzymes and antigens of H. pylori have been identified, many of which are potential virulence factors, including cytotoxin, adhesins, urease, outer membrane proteins, flagellins, at least one heat shock protein homolog, and catalase, among others. Biotyping schemes for H. pylori based on differences in protein composition are of limited utility. Several putative H. pylori adhesins have been identified which may contribute to its adherence to gastric mucosa. H. pylori possesses four to six sheathed unipolar flagella, each approximately 2.5-p.m long and 30 nm in diameter. Seropositivity in humans infected with H. pylori is strongly correlated with the presence of auto-antibodies against gastric mucosal cells. In vitro, catalase protects H. pylori by preventing the formation of toxic peroxidation products from long-chain saturated fatty acids.
