Vaccination against Helicobacter pylori infection

Abstract

Helicobacter pylori is well adapted to colonize the human gastric mucosa and induces a relatively mild but persistent inflammation and activation of adaptive B- and T-cell responses. A subset of infected individuals experience symptoms or develop ulcer disease or gastric adenocarcinoma that might be treatable with antibiotics. At the same time, the resistance to antibiotics is rapidly increasing among H. pylori isolates, and access to an efficient vaccine would improve treatment options considerably. Still, the complex pathogenesis and many different virulence factors of the bacterium have made vaccine development a challenging task. In this review, we discuss the possibilities of constructing a future vaccine against H. pylori based on the choice of antigens and mucosal adjuvants and describe our knowledge of protective immune responses that may be necessary to generate for eradication of H. pylori. In addition, the preclinical and clinical testing of available vaccine candidates is reviewed. The immunological response to H. pylori infection is multifaceted, and inflammatory responses are mounted side by side with a prominent regulatory response. The potential problems caused by the immune response, comprising both tolerance induction by the infection and the risk of developing post-immunization gastritis, are also discussed.