OBJECTIVETo investigate the effects of the two-valence vaccine consisting of Helicobacter pylori (H. pylori) catalase and urease subunit UreB in preventing H. pyloriinfection in mice.

METHODSC57BL/6 mice were divided into 7 groups and immunized with intragastric administration of catalase and UreB (both 100 microg) plus cholera toxin (CT, 2 microg), catalase (100 microg) plus CT (2 microg), UreB (100 microg) plus CT (2 microg), catalase (100 microg), UreB (100 microg), CT (2 microg), or PBS, respectively, once a week for 4 consecutive weeks. Two weeks after the last immunization, all the mice were challenged by live H. pylori, and sacrificed 4 weeks after the challenge to obtain the gastric mucosa samples for detecting H. pylori using semi-quantitative bacterial culture assay.

RESULTSThe total protection rate in mice immunized with the two-valence vaccine, single-valence vaccine of catalase, and single-valence vaccine of UreB was 83.3% (20/24), 41.7% (10/24) and 54.2% (13/24), respectively, and the rate in the other 4 groups were all 0. The H. pyloricolony density in mice with vaccination was significantly lower than that of other 4 groups (P<0.05). The total protection rate and H. pylori colony density differed significantly between the two-valence vaccination group and the single-valence vaccination groups (P<0.05).

CONCLUSIONThe two-valence vaccine consisting of catalase, UreB and adjuvant has better immunoprotective effects than the single-valence vaccines.