Local and systemic antibody responses in humans with Helicobacter pylori infection

Immunization can prevent or cure an otherwise chronic helicobacter infectio n in several animal models despite the chronic nature of natural helicobact er infections. Differences in the antigenic specificity of the antibodies m ay contribute to the protection observed in these experimental animals. The goal of the present study was to compare the local and systemic antibody r esponses of humans with chronic Helicobacter pylori infection with those of an individual with spontaneous resolution of infection to find an immunolo gical correlate of protection. Spontaneous resolution of infection was acco mpanied by a change in immunoblot profiles. Whereas a broad range of H pylo ri antigens was recognized in chronically infected patients (including the patient who ultimately cleared the infection spontaneously), resolution of infection in the absence of therapeutic agents resulted in the recognition of only several immunodominant antigens. The most dominant antigen was appr oximately 66 kDa in molecular mass. Immunoblot analysis demonstrated that t hese antibodies were specific for the structural subunits of the urease enz yme. These studies suggest that the success of antihelicobacter immunizatio n may be due to the ability of vaccination to induce an immune response aga inst antigens that are normally not immunodominant during the course of inf ection.