Systemic immunization with urease protects mice against Helicobacter pylori infection.

The ability of systemic immunization to induce protection against Helicobacter pylori infection has been evaluated in a mouse model. It was observed that if appropriate formulations and adjuvants were used such immunization elicited in outbred Swiss mice levels of protection similar or better than those induced by the oral route in the presence of cholera toxin or Escherichia coli heat labile toxin. Recombinant urease mixed with adjuvants, which induced strong Th1 and Th2 responses elicited better protection than urease mixed with adjuvants which induced a predominant Th2 type response only. These experiments demonstrate the feasibility of parenteral immunization against H. pylori and suggest that an appropriate balance between Th1 and Th2 type responses is required to achieve complete protection.