ABSTRACT
Objective:To investigate the role of recombinant phospholipase A2 receptor (PLA2R) tandem dominant epitopes (PLA2RTD) in the removal of anti-PLA2R autoantibodies (anti-PLA2R) from primary membranous nephropathy (PMN).Methods:The recombinant protein PLA2RTD (cysteine-rich domain, C-type lectin like domain 1 and C-type lectin like domain 7) was expressed in bacmid-insect cell expression system. Circular dichroism was used to determine the secondary structure of PLA2RTD. Enzyme-linked immunosorbent assay and immunofluorescence were used to determine the biological activity of PLA2RTD. Epoxy activation method was used to couple the recombinant PLA2RTD and agarose gel CL-6B microspheres for preparing specific immune adsorbent of anti-PLA2R.Results:The study achieved the expression of PLA2RTD in the first time from the bacmid-insect cell system, demonstrating the good immunogenicity and high binding specificity of PLA2RTD. A single in vitro adsorption of PLA2RTD could averagely eliminate 76.66% of anti-PLA2R [(6.66±0.30) RU/ml vs. (28.54±2.10) RU/ml], the changes of IgG, IgA, albumin, β2 microglobulin, interleukin 6, and tumor necrosis factor α were all less than 4% after completion of adsorption, and the second or third repeated use of PLA2RTD could maintain the adsorption efficiency of about 65%. Conclusion:PLA2RTD-based specific immunosorbent can effectively remove anti-PLA2R in plasma, which provides a new way to specifically remove PMN-related autoantibodies.