Detection and evaluation of antibodies against neutrophil-activating protein of Helicobacter pylori in patients with gastric cancer

• DOI: 10.3748/wjg.15.2381
• Publication Date: 2009-05-20T02:35:47Z
• Authors: Min Long; Jun Luo; Yan Li; Fang-Yin Zeng; Ming Li
• Keywords: Adult; Aged, 80 and over; DNA, Bacterial; 0301 basic medicine; Adolescent; Helicobacter pylori; Chemokine CXCL1; Immunoglobulin gamma-Chains; Interleukin-8; Age Factors; Enzyme-Linked Immunosorbent Assay; Epithelial Cells; Antibodies, Bacterial; Cell Line; 3. Good health; 03 medical and health sciences; Bacterial Proteins; Case-Control Studies; Gastritis; Escherichia coli; Humans; Cloning, Molecular; Aged

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.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.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.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.