Receptor Antibody Time-resolved A2 Phospholipase Bead Immunochromatography and Its Application in Idiopathic Membranous Nephropathy

Objective: To detect phospholipase A2 receptor (PLA2R) antibody by established time-resolved fluorescent bead immunochromatographic assay.

Methods: The reaction time of coupling, pH of the reaction, and coupling ratio of the label to PLA2R were determined. The EDC method was used to covalently couple PLA2R to time-resolved fluorescent beads, which were sprayed onto a bonding pad. PLA2R and rabbit anti-PLA2R antibody sprayed onto a nitrocellulose membrane were used as detection and quality control lines, respectively. Immunochromatographic test strips were prepared to enable rapid detection of PLA2R antibodies. Various technical indicators were evaluated, and the correlation among this method, enzyme-linked immunosorbent assay (ELISA), and serum analysis was examined.

Results: The pH suitable for labeling was 6.5. The optimal mass ratio of PLA2R protein to fluorescent beads was 0.08:1, and the reaction time of coupling was at least 1.5 hours. The appropriate spray film size of the coupled fluorescent bead was 5 μL/cm, and the appropriate staining concentration of the test line was 0.28 mg/mL. Further, 80 µL of sample was required for the test, and the result was obtained in only 15 minutes. The measurable range of this method was 5-1500 RU/mL. Intra- and inter-assay coefficients of variation were 7.61% and 11.07%, respectively, with an average recovery rate of 93.77%. The method showed a good correlation with ELISA, with a correlation coefficient of 0.936.

Conclusions: This method could better meet the clinical demand for idiopathic membranous nephropathy (IMN) detection.