Protective efficacy of recombinant urease B and aluminum hydroxide against Helicobacter pylori infection in a mouse model.

Efforts are underway for the development of an effective vaccine against Helicobacter pylori infection. We prepared recombinant full-length (568 aa) H. pylori recombinant urease B (rUreB) protein and tested it for immunogenicity and protection. BALB/c mice received either rUreB (40 μg) plus CpG (10 μg) intranasally, rUreB (50 μg) plus 3% aluminum hydroxide (50 μL) intramuscularly or rUreB (25 μg) plus Freund's adjuvant (25 μL) subcutaneously, three times (weeks 0, 2 and 6). Intranasal rUreB plus CpG was neither immunogenic nor protective; intramuscular rUreB plus aluminum hydroxide was immunogenic and modestly protective, and subcutaneous rUreB plus Freund's adjuvant was immunogenic and highly protective. The fact that protection was improved with Freund's adjuvant indicates that rUreB is a good antigen for a vaccine but that it needs a stronger adjuvant than aluminum hydroxide.