Figure 4.

Effectiveness of immunization by DC from Hp^+/+ and Hp^−/− mice and influence of systemic Hp. (A) Groups of 5 Hp^+/+ and Hp^−/− C57BL/6 mice received 1 × 10⁶ matured bone marrow-derived DC from C57BL/6J.Hp^+/+ or Hp^−/− mice (Day –5). Prior to transfer, the DC had been treated for 4 h with OVA, followed by 16 h with LPS. One culture with Hp^−/− DC also included 1 mg/ml mouse Hp. The recipient mice were challenged i.p. with 1 × 10⁶ E.G7 (EL4 OVA-expressing thymoma) tumor cells (=Day 0). Mice were then monitored for survival. In Hp^+/+ mice, Hp^+/+ DC versus Hp^−/− DC: P = 0.01; Hp^−/− DC + mouse Hp (mHp) versus Hp^−/− DC: P = 0.02. (B) Bone marrow-derived DC from the indicated genotypes (1×10⁶ cells/ml) were treated for 24 h with LPS (1 μg/ml) or Hp (1 mg/ml). The expression of cell surface markers was identified by flow cytometry, and the cytokine concentrations in the conditioned medium were determined by Luminex immunobead assay. Data represent the results from one experimental series. Although secretion rate varies among independently derived cell preparations, in three series, an identical trend in Hp-dependent cytokine regulation was determined.