Development of a sensitive enzyme-linked immunosorbent assay for measurement of DNase I in human serum

Abstract

Background Serum deoxyribonuclease I (DNase I) activity was reported to increase in the early phase after onset of acute myocardial infarction (AMI). Up to now, DNase I activity has been quantified by the single radial enzyme diffusion (SRED) method, which unfortunately requires a long incubation time. Therefore it is necessary to develop another assay suitable for measurement of serum DNase I concentrations in a clinical setting. Methods A sandwich ELISA was established for measurement of DNase I protein using a polyclonal antibody directed against DNase I protein and a biotinylated monoclonal for subsequent detection. Concentrations of serum DNase I protein were measured in healthy individuals and patients with AMI. Results This method was as precise as SRED, and took less time than SRED. A significant correlation was observed between DNase I concentration and enzyme activity ( r = 0.839; P < 0.001). The average of serum DNase I in AMI patients within 0–12 h of chest pain was significantly higher than that in healthy individuals ( P < 0.001), and decreased with time. Conclusions We have developed a sensitive ELISA capable of measuring DNase I protein concentrations. This method may be a useful alternative to SRED as an aid to diagnosis of AMI based on the serum DNase I level.