Phospholipase A2 Receptor 1 (PLA2R1) is a type I transmembrane glycoprotein belonging to the mannose receptor family. It is primarily expressed on the surface of podocytes in the kidney glomerulus and plays important roles in cell senescence, apoptosis, and maintaining glomerular filtration barrier function. PLA2R1 has gained significant clinical attention as it is identified as the major autoantigen in primary membranous nephropathy, where autoantibodies against PLA2R1 are pathogenic drivers of the disease. Besides, PLA2R1 functions as a specific receptor that binds secreted PLA2G2, thus a functional binding ELISA assay was conducted to detect the interaction of recombinant human PLA2R1 and recombinant human PLA2G2. Briefly, PLA2G2 was diluted serially in PBS with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to PLA2R1-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST and incubated for 1h with anti-PLA2G2 pAb, then aspirated and washed 3 times. After incubation with HRP labelled secondary antibody for 1h at 37℃, wells were aspirated and washed 5 times. With the addition of substrate solution, wells were incubated 15-25 minutes at 37℃. Finally, add 50 µL stop solution to the wells and read at 450/630nm immediately. Measured by its binding ability in a functional ELISA. When Recombinant PLA2R1 is lmmobilized at 2 µg/mL(100 uLwell), the concentration of PLA2G2 that produces 50% optimal bindingresponse is found to be approximately 0.12 µg/mL.