Combined Immunization Methods May Offer Long-Term Protection Against H. pylori Infection
New immunization methods offer long-term protection against H. pylori in humans and may contribute to a possible ulcer vaccine in the future say researchers from the University of California, Davis. They report their findings in the July 2007 journal Infection and Immunity.
Helicobacter pylori is a bacterium that colonizes the digestive tract of 50% of the worlds population. Infection commonly occurs in early childhood and can lead to chronic gastritis, peptic ulcer disease and gastric cancer throughout the life of its host. Antibiotics are currently used against H. pylori infection, however increasing resistance as well as high treatment costs and recurrence of infection emphasize the need for an effective, long-lasting vaccine.
In the study mice were immunized in four groups: orally alone, intramuscularly alone, orally followed by intramuscularly, and intramuscularly followed by orally and then challenged orally with H. pylori after three months. Results showed that mice receiving intramuscular immunization alone or a combination of oral and intramuscular vaccinations had significantly reduced bacterial loads and no detectible H. pylori in the intestinal tract. Mice immunized orally alone or intramuscularly followed by orally were not protected and had decreased antibody responses.
This study demonstrates the ability to induce long-term immunity against H. pylori, provides correlates of protection, and illustrates the crucial role of the immunization route(s), say the researchers.
(J.M. Taylor, M.E. Ziman, J. Fong, J.V. Solnick, M. Vajdy. 2007. Possible correlates of long-term protection against Helicobacter pylori following systemic or combinations of mucosal and systemic immunizations. Infection and Immunity, 75. 7: 3462-3469).