Utilization of Proteinase K‐Treated Cells as Lipopolysaccharide Antigens for the Serodiagnosis of Helicobacter pylori Infections

Abstract

We have evaluated the use of proteinase K (PK)-treated cells isolated from Helicobacter pylori as lipopolysaccharide (LPS) antigens in an immunoblot assay and an enzyme-linked immunosorbent assay (ELISA) for the serodiagnosis of H. pylori infection. The sera from patients with chronic gastritis, gastric ulcer, duodenal ulcer or gastric cancer, and from healthy adults with or without H. pylori infection were assayed with three commercial serodiagnostic kits (HM-CAP, Helico-G, and G.A.P. II) and novel methods relying on the use of PK-treated cells. The PK-treated cells used in these assays were selected on the basis of their possibility to possess a common epitope in the 0-polysaccharides of H. pylori, which is known to be highly immunogenic in humans. Of the sera from these patients, 71-94% were positive with the commercial kits, 97 % with immunoblot assay, and 90% with ELISA. On the other hand, of the healthy adults infected with H. pylori, 72-97% were positive with the commercial kits, 86% with immunoblot assay, and 72% with ELISA. PK-treated cells that did not contain the common epitope were unsuitable as an antigen for immunoblot assay or ELISA. Furthermore, the reactivity of these sera reacted specifically with H. pylori PK-treated cells but not with LPSs from other gram-negative bacteria, such as Campylobacter, Proteus, Bordetella, and Salmonella. These results demonstrate that the serological assays relying on the use of H. pylori PK-treated cells possessing a highly antigenic epitope are potentially useful as a serodiagnostic test for H. pylori infection.

Implication of Antigenic Conversion of Helicobacter pylori Lipopolysaccharides That Involve Interaction with Surfactant Protein D

“…H. pylori carrying the HA-LPS is dominant during relatively early periods of infection, and high titers of antibodies to this epitope are elicited. This is supported by the fact that high titers of anti-highly antigenic epitope antibodies are found in almost all individuals infected with H. pylori regardless of antigenic type of infected H. pylori (1,36). H. pylori carrying HA-LPS is considered to escape from innate immunity involving SP-D, because HA-LPS does not interact significantly with the SP-D via its CRD.…”

“…H. pylori clinical isolates were described previously (37). Sera derived from individuals infected with H. pylori were obtained as previously described (1,37).…”

Comparison of serum antibody titers to Helicobacter pylori lipopolysaccharides, CagA, VacA and partially purified cellular extracts in a Japanese population

“…ELISA was carried out basically as described previously [6,7]. LPS antigens were diluted in 50 mM sodium carbonate bu¡er (pH 9.6) to a ¢nal concentration of 5 Wg ml 31 .…”

Ciliostasis is a key early event during colonization of canine tracheal tissue by Bordetella bronchiseptica

“…B. pertussis and B. parapertussis cause whooping cough in children (Amano et al, 1998;Cherry, 1996) and B. pertussis is now recognized as a cause of chronic cough in adults (Nennig et al, 1996). A different lineage of B. parapertussis can also infect sheep (Porter et al, 1996).…”