title: Systemic Th1 immunization of mice against Helicobacter pylori infection with CpG oligodeoxynucleotides as adjuvants does not protect from infection but enhances gastritis.
abstract: Recent reports have suggested that oral vaccination of mice against Helicobacter pylori is dependent on a Th1-mediated immune response. However, oral vaccination in mice neither induces sterilizing immunity nor leads to complete protection from disease. Therefore, in this study we investigated whether a systemic subcutaneous immunization against H. pylori by using CpG oligodeoxynucleotides as a Th1 adjuvant could achieve protection in a mouse model of H. pylori infection. CpG oligodeoxynucleotides are known for their ability to induce nearly entirely Th1-biased immune responses and may be approved for human use in future. Immunization of mice with H. pylori lysate and CpG induced a strong local and systemic Th1 immune response. Despite this strong Th1 response, mice were not protected from infection with H. pylori yet had a 10-fold reduction in the number of H. pylori in the gastric mucosa compared to nonimmunized mice. Of note, reduction of the bacterial density in immunized mice was accompanied by a significantly enhanced gastritis. Hence, systemic Th1 immunization of mice, even though being able to reduce the bacterial load in the stomach, is associated with aggravated pathology.
authors.affiliation: Institut fuer Medizinische Mikrobiologie und Hygiene, University of Marburg, Marburg, Germany. sommerf@mailer.uni-marburg.de
authors.forename: Frank
authors.initials: F
authors.lastname: Sommer
authors.forename: Henning
authors.initials: H
authors.lastname: Wilken
authors.forename: Gerhard
authors.initials: G
authors.lastname: Faller
authors.forename: Michael
authors.initials: M
authors.lastname: Lohoff
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001428:Bacterial Vaccines / Q000276:immunology*; D005260:Female; D005756:Gastritis / Q000209:etiology*; D016481:Helicobacter Infections / Q000517:prevention & control*; D016480:Helicobacter pylori / Q000276:immunology*; D007114:Immunization; D018664:Interleukin-12 / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D009838:Oligodeoxyribonucleotides / Q000494:pharmacology*; D018417:Th1 Cells / Q000276:immunology*
chemical_list: D000276:Adjuvants, Immunologic; D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; C408982:CPG-oligonucleotide; D009838:Oligodeoxyribonucleotides; D018664:Interleukin-12