Helicobacter pylori in gastric cancer and peptic ulcer disease in a Colombian population. Strain heterogeneity and antibody profiles.

Abstract

Helicobacter pylori infection is associated with peptic ulcer disease and gastric cancer. The aim of this work was to describe, to compare H. pylori antigenic profiles, and to characterize the antibody response against Colombian strains in gastric cancer and peptic ulcer patients. Liquid culture supernatants were used to determine the antigenic profiles of 35 H. pylori strains by immunoblotting using a pool of positive sera. Characterization of strains included the evaluation of cytotoxic and vacuolating activities. The serologic antibody profiles of 124 patients (54 duodenal ulcer and 70 gastric cancer) were analyzed against two native strains (Hpu24, Hpc29) and NCTC11638. Antibodies to specific antigenic bands in each strain were related with presentation. Differences among antigenic profiles were observed between native isolates with each serum recognizing a wide range of antigens (30-120 Kd). A 68 Kd band in Hpu24 strain was recognized by 50% of sera from peptic ulcer patients but not by gastric cancer sera (p =.000). The immune profiles differed according to the strain used (i.e. a given sera did not recognize the same bands in different strains). Detection of H. pylori in gastric mucosa was associated with the presence of antibodies against low molecular weight antigenic bands. The heterogeneity in the antibody response to H. pylori and the prevalence specific anti-H. pylori antibodies in a specific disease depend on the strain used as antigen. The results support the hypothesis that there may be a differential antibody response to carcinogenic and ulcerogenic strains and suggest that there are antigenic bands that could be useful as markers of disease.