K. Amano et al., UTILIZATION OF PROTEINASE K-TREATED CELLS AS LIPOPOLYSACCHARIDE ANTIGENS FOR THE SERODIAGNOSIS OF HELICOBACTER-PYLORI INFECTIONS, Microbiology and immunology, 42(7), 1998, pp. 509-514
We have evaluated the use of proteinase K (PK)-treated cells isolated
from Helicobacter pylori as lipopolysaccharide (LPS) antigens in an im
munoblot assay and an enzyme-linked immunosorbent assay (ELISA) for th
e serodiagnosis of H, pylori infection. The sera from patients with ch
ronic gastritis, gastric ulcer, duodenal ulcer or gastric cancer, and
from healthy adults with or without H. pylori infection were assayed w
ith 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 O-polysaccharides of H
, pylori, which is known to be highly immunogenic in humans. Of the se
ra 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 reactiv
ity of these sera reacted specifically with H. pylori PK-treated cells
but not with LPSs from other gram-negative bacteria, such as Campylob
acter, 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.