Enzyme-linked immunosorbent assay of serum pepsinogen I

A hybridoma monoclonal antibody against human pepsinogen I was used to develop an enzyme-linked immunosorbent assay for pepsinogen I in serum. In the two-step competitive procedure using antimouse immunoglobulin F(ab')2 fragment coupled to alkaline phosphatase, the measurable assay range was 8-256 micrograms/l. No cross-reactivity with rat pepsinogen 1, human pepsinogen II, gastrin I, bombesin, somatostatin and peptide YY was shown. However, there was slight cross-reactivity (0.09%) with porcine pepsinogen. The coefficients of variation within and between series were 7.6% and 13.0%. This enzyme-linked immunosorbent assay for serum pepsinogen I correlated positively with radioimmunoassay (r = 0.87, n = 92). The concentration range of serum pepsinogen I in 354 healthy controls was 15-100 micrograms/l with a lognormal distribution. Serum pepsinogen I levels were significantly higher in the subjects who developed active duodenal ulcer or active gastric ulcer, but significantly lower in those who had gastric cancer, than in control subjects.