Preface

Helicobacter pylori has been identified as a causative agent of gastroduodenal pathology. Vaccination studies with mouse models have shown that immunisation with bacterial antigens can provide protection against infection, indicating that it may be possible to design vaccines which terminate colonisation byH pylori or prevent it from taking place. Here, we review critically current knowledge of naturally acquired human humoral and cellular immune responses to H pylori with the aim of delineating questions which should be tackled in order to permit a rational and directed approach to the development of an effective vaccine. We have also reviewed the literature and identified candidate vaccine antigens.

H pylori is a Gram negative flagellated bacterium which lives both in the mucus gel layer that coats the gastric mucosa and between the mucus gel layer and the apical surfaces of gastric mucosal epithelial cells. Although it seems to be largely extracellular, some invasion of gastric cells has been reported.1 In Western countries, H pylori infection increases from a low prevalence in childhood to about 20% of people below 40 years of age,2 with a steep rise in infection rates to 50% at age 60, attributed to increased infection during the Second World War. In underdeveloped countries, acquisition of infection occurs in 10% of children per annum so that 90% are infected by their teenage years.

There is a strong association between gastric H pylori infection and gastroduodenal disease.3 The presence of the bacterium invariably causes the surrounding mucosa to become inflamed,3-5 and the degree of gastritis present is positively correlated with the extent of H pylori colonisation.3 ,6 Although most people infected with H pylori remain asymptomatic, in some the gastritis progresses to more severe forms of gastroduodenal pathology. Atrophy, characterised by distortion and destruction of the …