DETECTION IN AN ENZYME-IMMUNOASSAY OF AN IMMUNE-RESPONSE TO A RECOMBINANT FRAGMENT OF THE 128-KILODALTON PROTEIN (CAGA) OF HELICOBACTER-PYLORI

The possibility of using a recombinant fragment of the CagA (128 kDa p rotein) for the diagnosis of Helicobacter pylori infection was evaluat ed. Following cloning of the gene coding for the CagA, a recombinant f ragment of it was expressed in Escherichia coli, purified and used in Western blot and an EIA to screen sera from 82 patients with gastroduo denal disease who underwent endoscopic examination. In Western blot, g ood correlation was found between the serological data obtained with t he recombinant antigen and those obtained using non-purified extracts of Helicobacter pylori. The EIA using the antigen showed a sensitivity of 96.2% and a specificity of 96.6% compared with Western blot. These data indicate that the recombinant protein is a reliable antigen for detection of infections with Helicobacter pylori strains that are asso ciated with disease. The EIA assay described may be used in follow-up of the progression of the illness and the results of therapy.