Use of Immunoblot Assay To Define Serum Antibody Patterns Associated with Helicobacter pylori Infection and with H. pylori -Related Ulcers

Abstract

Serology has been used worldwide to detect Helicobacter pylori infection. Using an immunoblot assay with an antigen from strain ATCC 43579, we sought to determine the antibodies which were good markers of colonization and the antibody patterns associated with ulcers or atrophy. Out of 98 dyspeptic patients, 41 were colonized byH. pylori, based on a positive culture or on positive results of both a urease test and direct examination. These 41 patients were seropositive by an enzyme immunoassay, and 12 of them had ulcers and 29 had evidence of atrophy. Fifty-seven of the 98 patients were noncolonized. Twenty-five of the 57 had evidence of gastric atrophy, and 10 were seropositive; 5 of these 10 had ulcers. By Western blot analysis, 12 antibodies were significantly more frequent in sera from colonized patients, and they produced immunoreactive bands at 125, 87, 74, 66, 54, 48, 46, 42, 35, 30, 16 and 14 kDa. The presence of at least one band at 54, 35, or 42 kDa was the best marker of infection (sensitivity, 95%; specificity, 82%). In the group of colonized patients, none of the antibody patterns were correlated to gastric atrophy. Conversely, the presence of a band at 125, 87, or 35 kDa was statistically associated with the presence of an ulcer. The simultaneous presence of bands at 87 and 35 kDa predicted the risk of ulcers with 83% sensitivity and 69% specificity. By using CagA-positive and VacA-positive strains and CagA-negative and VacA-negative isogenic mutants, the antigens corresponding to the bands at 125 and 87 kDa were shown to be CagA and VacA, respectively. On the other hand, the 35-kDa antigen is a novel uncharacterized component ofH. pylori. These results may help to optimize the composition of antigenic preparations for serologic detection ofH. pylori colonization. Immunoblot assay would be useful for screening patients at high risk of ulcers.

cagA gene and vacA alleles in Spanish Helicobacter pylori clinical isolates from patients of different ages

“…pylori infection can lead to a variety of diseases. At present, the only way to identify the illness associated with H. pylori infection is by an endoscopy examination, together with histologic examination of the gastric mucosa [20]. The prevalence of the cagA gene and vacA alleles amongst Spanish H. pylori clinical isolates increased with age, and was more frequent in older patients than in younger.…”

Clinical and pathological implications of IgG antibody responses toHelicobacter pyloriand its virulence factors in non‐ulcer dyspepsia

“…[10][11][12][13][14][15][16][17] A low-molecular-weight protein has also been found to be associated with peptic ulcer disease. [18][19][20] Although preliminary studies have failed to detect an association between VacA, CagA and the 35-kDa protein and non-ulcer dyspepsia, 21,22 these studies were limited by the small numbers of patients or a lack of healthy controls. 19,22 Clinical trials employing eradication therapy in patients with non-ulcer dyspepsia may provide new insights into the association between infection with specific H. pylori strains and non-ulcer dyspepsia, by detecting the pre-treatment immunoglobulin G (IgG) antibody responses to specific virulence factors of H. pylori.…”

Human serum antibody response toHelicobacter pyloriwhole cell antigen in an institutionalized Bangladeshi population

“…Helicobacter pylori is recognized as a major cause of gastritis and peptic ulcer and a key factor in the development of gastric cancer, gastric lymphoma and non-ulcerative dyspepsia in man (Karvar et al 1997). Strains carrying the genes encoding the cytotoxin-associated protein (cagA) are associated with duodenal ulcers and gastric cancer (Aucher et al 1998). Patients infected with these organisms have been shown to produce serum antibodies to H. pylori antigens and several studies have implied that the immune response correlates with the histological ®ndings in biopsy specimens (Drumm et al 1990;Aguirre et al 1992;Schembri et al 1993).…”

“…Serological studies have shown that strains carrying the cagA gene are more often associated with severe gastroduodenal outcomes such as peptic ulcer disease (PUD) and distal adenocarcinoma (Aucher et al 1998). Several studies have reported that CagA-producing strains account for > 90% of H. pylori isolates from humans in developing countries, compared with only approx.…”