Detection and evaluation of antibodies against neutrophil-activating protein of Helicobacter pylori in patients with gastric cancer.
OBJECTIVE
To detect and evaluate the antibodies against Helicobacter pylori (H pylori) neutrophil-activating protein (HP-NAP) in patients with gastric cancer and other gastroduodenal diseases.


METHODS
Recombinant HP-NAP was prepared from a prokaryotic expression system in Escherichia coli. Serum positivity and level of HP-NAP-specific antibodies in sera from 43 patients with gastric cancer, 28 with chronic gastritis, 28 with peptic ulcer, and 89 healthy controls were measured by rHP-NAP-based ELISA. rHP-NAP-stimulated production of interleukin-8 (IL-8) and growth-related oncogene (GRO(alpha)) cytokines in the culture supernatant of SGC7901 gastric epithelial cells was also detected.


RESULTS
The serum positivity and mean absorbance value of HP-NAP-specific antibodies in the gastric cancer group (97.7% and 1.01 +/- 0.24) were significantly higher than those in the chronic gastritis group (85.7% and 0.89 +/- 0.14, P < 0.005) and healthy control group (27.7% and 0.65 +/- 0.18, P < 0.001). The sensitivity and specificity of ELISA for the detection of HP-NAP-specific antibodies were 95.5% and 91.5%, respectively. HP-NAP could slightly up-regulate IL-8 production in gastric epithelial cell lines but had no effect on GRO(alpha) production.


CONCLUSIONS
Infection with virulent H pylori strains secreting HP-NAP is associated with severe gastroduodenal diseases, and HP-NAP may play a role in the development of gastric carcinoma. rHP-NAP-based ELISA can be used as a new method to detect H pylori infection. The direct effect of HP-NAP on gastric epithelial cells may be limited, but HP-NAP may contribute to inflammatory response or carcinogenesis by activating neutrophils.
Long
Min
M
School of Biotechnology, Southern Medical University, Guangzhou, Guangdong Province, China.
Luo
Jun
J
Li
Yan
Y
Zeng
Fang-Yin
FY
Li
Ming
M
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000907:Antibodies, Bacterial / Q000097:blood*; D001426:Bacterial Proteins / Q000378:metabolism*; D016022:Case-Control Studies; D002460:Cell Line; D054360:Chemokine CXCL1 / Q000096:biosynthesis; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D004847:Epithelial Cells / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D005756:Gastritis / Q000276:immunology; D016480:Helicobacter pylori / Q000235:genetics / Q000276:immunology*; D006801:Humans; D007142:Immunoglobulin gamma-Chains / Q000097:blood; D016209:Interleukin-8 / Q000096:biosynthesis; D008875:Middle Aged; D008969:Molecular Sequence Data; D010437:Peptic Ulcer / Q000276:immunology; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000096:biosynthesis; D013274:Stomach Neoplasms / Q000276:immunology*; D055815:Young Adult
D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D054360:Chemokine CXCL1; D004269:DNA, Bacterial; D007142:Immunoglobulin gamma-Chains; D016209:Interleukin-8; D011994:Recombinant Proteins; C092412:neutrophil-activating protein A, Helicobacter pylori