Protective anti-helicobacter immunity is induced with aluminum hydroxide or complete Freund's adjuvant by systemic immunization

To determine whether systemic immunization against Helicobacter pylori could be achieved with an adjuvant approved for human use, the efficacy of vaccination with Helicobacter antigen in combination with aluminum hydroxide (AIOH) was evaluated in a murine model of Helicobacter infection. Immunization with antigen and AIOH induced interleukin-5-secreting, antigen-specific T cells, and immunization with antigen and complete Freund's adjuvant induced interferon-γ-secreting, antigen-specific T cells, as determined by ELISPOT assay. Both immune responses conferred protection after challenge with either H. pylori or H. felis, as confirmed by the complete absence of any bacteria, as assessed by both histology and culture of gastric biopsy samples. Protection was antibody independent, as demonstrated with antibody-deficient μMT mice (immunoglobulin-gene knockout mice), and CD4⁺ spleen T cells from immunized mice were sufficient to transfer protective immunity to otherwise immunodeficient rag1^-/- recipients. These results suggest an alternative and potentially more expeditious strategy for development of a human-use H. pylori vaccine.