Enhanced chemiluminescence enzyme-linked immunoassay for the determination of DNA methyltransferase 1 in human serum.

The occurrence of many diseases is closely related to the high expression of DNA methyltransferase 1 (DNMT1). However, most studies are focused on the detection of DNMT1 activity, a few are concerned with the detection of DNMT1 content. In this study, we developed a simple and highly sensitive chemiluminescence (CL) assay for the detection of DNMT1 content. In this method, anti-DNMT1 monoclonal antibody was coated on a polystyrene microplate to capture DNMT1. Then anti-DNMT1 polyclonal antibody and goat anti-rabbit immunoglobulin G with horseradish peroxidase (IgG-HRP) were respectively added to combine with captured DNMT1 to form a sandwich structure. Finally, the HRP could catalyze CL substrate and achieve CL signal response. Based on this novel sensitive strategy, the recovery percents were in the ranges from 71.5% to 91.0%. The precision of intra-assays and inter-assays were 5.45%-11.29% and 7.03%-11.25%, respectively. The method was successfully applied for the determination of DNMT1 in human serum. The detection results of serum samples showed that the proposed assay had a high correlation with enzyme-linked immunosorbent assay (ELISA) kit. Compared with the ELISA kit (limit of detection = 0.1 ng/mL), the method has a lower limit of detection of 0.042 ng/mL. Therefore, our method has the potential for the detection of DNMT1 content in clinical diagnosis.