Kidney Week

Abstract: FR-OR31

Human PLA2R-Antibodies Induce Membranous Nephropathy in Minipigs

Session Information

• Glomerular Diseases: Antibodies, Complement, and Inflammatory Mediators
  November 05, 2021 | Location: Simulive, Virtual Only
  Abstract Time: 04:30 PM - 06:00 PM

Category: Glomerular Diseases

• 1202 Glomerular Diseases: Immunology and Inflammation

Authors

• Reinhard, Linda, Universitatsklinikum Hamburg-Eppendorf, Hamburg, Hamburg, Germany

Linda Reinhard, PhD

• Wiech, Thorsten, Universitatsklinikum Hamburg-Eppendorf, Hamburg, Hamburg, Germany

Thorsten Wiech,

• Schweizer, Michaela, Universitatsklinikum Hamburg-Eppendorf Zentrum fur Molekulare Neurobiologie Hamburg, Hamburg, Hamburg, Germany

Michaela Schweizer,

• Meyer-Schwesinger, Catherine, Universitatsklinikum Hamburg-Eppendorf, Hamburg, Hamburg, Germany

Catherine Meyer-Schwesinger,

• Groene, Hermann-Josef, Universitatsklinikum Hamburg-Eppendorf, Hamburg, Hamburg, Germany

Hermann-Josef Groene,

• Hoxha, Elion, Universitatsklinikum Hamburg-Eppendorf, Hamburg, Hamburg, Germany

Elion Hoxha,

• Stahl, Rolf A., Universitatsklinikum Hamburg-Eppendorf, Hamburg, Hamburg, Germany

Rolf A. Stahl,

Background

PLA₂R is the main target antigen in patients with membranous nephropathy (MN). The pathogenicity of PLA₂R-antibodies (ab) in MN patients have so far not been proven. This study aimed to prove the pathogenicity of human PLA₂R-ab in MN, and to induce an active PLA₂R-dependend model of MN in minipigs.

Methods

In a first model, plasma and purified IgG from patients with PLA₂R-ab positive MN and healthy donors (negative control) were transferred into minipigs. In a second model, human PLA₂R-protein was used for active immunization of a minipig. We analyzed the PLA₂R-ab in serum, development of proteinuria as well as kidney tissues using immunohistochemistry, immunofluorescence, electron microscopy and “podocyte exact morphology measurement (PEMP)”.

Results

After transfer into minipigs, the human PLA₂R-ab bound specifically to minipig PLA₂R in the glomeruli and induced all morphologic characteristics of human MN. Human PLA₂R-ab of the IgG4 subclass could be eluted from minipig glomeruli, showing that the antibodies were able to bind to PLA₂R in the absence of other human serum components.
The active immunization of minipigs with human PLA₂R-protein led to the development of PLA₂R-ab, which recognized the N-terminal CysR-CTLD1-region, as well as the C-terminal CTLD7-8-region. Analyses of the kidney tissue revealed all morphologic characteristics of human MN, including a granular deposition of pig IgG and C3 along the glomerular basement membrane, as well as electron dense immune deposits, which were associated with effacement of podocyte food processes. Antibodies eluted from isolated glomeruli were able to bind human and minipig PLA₂R. The minipig developed moderate proteinuria. In contrast, no morphologic or clinical characteristics of MN were detectable in the control animal.

Conclusion

Human PLA₂R-ab induce MN in minipigs. Immunization of minipigs with PLA₂R-protein leads to the development of autoimmune PLA₂R-induced MN, which presents with activation of the complement system and all morphologic and clinical characteristics of human MN. These findings prove the pathogenicity of human PLA₂R-ab and fulfill Koch's postulate.

Funding

• Government Support – Non-U.S.