Figure 2. Immunization is protective in mice lacking IL-12.

(a) Female WT C57BL/6 and IL-12p35 KO mice, or (b) WT C57BL/6 male mice, were intranasally immunized once a week for four weeks with 100 µg of H. felis sonicate plus 5 µg of cholera toxin. On day 14 post-immunization, immunized mice, as well as unimmunized control mice were challenged by orogastric gavage with 1×10⁷ CFU H. pylori. Gastric biopsies were harvested from all mice four weeks post-challenge and evaluated for bacterial load by CFU determination. n = 5–6 mice/group.