Systemic Th1 immunization of mice against Helicobacter pylori infection with CpG oligodeoxynucleotides as adjuvants does not protect from infection but enhances gastritis.

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.