The ability of systemic immunization to induce protection against Heli
cobacter 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 simi
lar or better than those induced by the oral route in the presence of
cholera toxin or Escherichia coli heat labile toxin. Recombinant ureas
e mixed with adjuvants, which induced strong Th1 and Th2 responses eli
cited better protection than urease mixed with adjuvants which induced
a predominant Th2 type response only. These experiments demonstrate t
he feasibility of parenteral immunization against H. pylori and sugges
t that an appropriate balance between Th1 and Th2 type responses is re
quired to achieve complete protection. (C) 1998 Elsevier Science Ltd.
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