BACKGROUND & AIMS: Previous findings suggest that TH1 cellular immune responses contribute to Helicobacter-associated gastritis. To further investigate this issue, interleukin 4 gene targeted mice were infected with Helicobacter felis, and a series of adoptive transfer experiments was performed to evaluate the role of both TH1 and TH2 cells. METHODS: Antigen-specific spleen cells from immunized/challenged or nonimmunized/infected mice or CD4+ T-cell lines were transferred adoptively into naive recipients before live bacterial challenge. RESULTS: Transfer of cells from both groups of donors as well as TH1 or TH2 cell lines exacerbated gastric inflammation in the recipients. No effect on bacterial load was observed in recipients of bulk spleen cells from infected mice or recipients of TH1 cell lines. In contrast, when either a TH2 cell line or bulk cells from immunized challenged mice were transferred adoptively, recipients showed a dramatic reduction in bacterial load. Increased numbers of bacteria were also noted in interleukin 4-deficient mice. CONCLUSIONS: These data suggest a differential contribution of TH1 and TH2 cell-mediated immune responses in Helicobacter infection: one associated with the pathogenesis of disease (TH1 phenotype) and the other associated with protection from or control of infection (TH2 phenotype).

*CD4-Positive T-Lymphocytes/PHYSIOLOGY *Gastritis/MICROBIOLOGY *Helicobacter/ISOLATION & PURIF *Helicobacter Infections/IMMUNOLOGY

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