Helicobacter pylori

Helicobacter pylori is a motile, helix-shaped Gram-negative, microaerophilic, bacterial pathogen which is capable of converting from a spiral form to a coccoid form to favor its survival. Almost 50% of the world's population, approaching 100% in some countries, are infected. There are numerous strains of Helicobacter pylori which can be grouped into two broad families, type I and type II, based on their expression of the hopQ allele. Type I and type II strains are reported to express VacA (vacuolating toxin) responsible for vacuolation of gastric epithelial cells and induction of apoptosis. Type I strains are reported to express CagA protein which is associated with deregulation of intercellular signaling pathways and initiation of pathogenesis (virulent strains) and are closely related to gastric diseases such as peptic ulceration, gastric ulceration, chronic gastritis, mucosa-associated lymphoid tissue (MALT) lymphoma and intestine type gastric adenocarcinomas. Type II strains are reported not to express CagA proteins. HopE is a 31 kD porin protein which is part of a family of 32 outer membrane proteins present in Helicobacter pylori bacteria. HopE is highly conserved in Helicobacter pylori strains, but not among other strains of the Helicobacter genus.

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Helicobacter pylori is recommended for the detection of specific antigens of interest in normal and neoplastic tissues, as an adjunct to conventional histopathology using non-immunologic histochemical stains.