Journal Club #8: The Role of Epitope Retrieval in the Production of Anti-Glomerular Basement Membrane Antibodies in the Antibody-Associated Vasculitis Model

A recent publication from Yuka Nishibata et al. in the Research Square Journal implicated epitope retrieval in the production of anti-glomerular basement membrane (GBM) antibodies in an anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) model, as confirmed by Chondrex, Inc.’s rat anti-α3 chain of the non-collagenous region of type IV collagen (α3(IV)NC1) monoclonal antibody (mAb), H31, IgG2a.

AAV is a systemic small vessel disease characterized by necrosis of blood vessels and ANCA in the serum. On the other hand, anti-GBM diseases are usually organ-specific autoimmune disorders which manifest severe renal disease, pulmonary hemorrhage, and the production of anti-GBM antibodies. Approximately 5% of AAV patients have serum anti-GBM antibodies. An AAV model in WKY rats was used to study the role antigen retrieval plays in inducing anti-α3(IV)NC1 antibodies.

The anti-α3(IV)NC1 mAb failed to bind to the GBM and the basement membrane of Bowman’s capsule in formalin-fixed, paraffin-embedded normal kidney sections without antigen retrieval using immunohistochemistry. However, the mAb bound to retrieved antigens who received heat treatment under acidic conditions, a treatment of proteases from S. griseus or neutrophil elastase, but not with heat treatment under neutral and alkaline conditions. This suggested that ANCA activated neutrophils may digest type IV collagen, uncovering epitopes such as α3(IV)NC1.

For more information, please refer to the following link.

Y. Nishibata, M. Nonokawa, Y. Tamura, R. Higashi, K. Suzuki, H. Hayashi, et al., Possible implication of intermolecular epitope spreading in the production of anti-glomerular basement membrane antibody in anti-neutrophil cytoplasmic antibody-associated vasculitis. Clin Exp Rheumatol 40(4), 691-704 (2022).

In order to study the contribution of autoantibodies to disease in rat nephritis models, Chondrex, Inc. provides epitope defined monoclonal antibodies against each α chain (IV)NC1, nephritogenic monoclonal antibodies and nephritogenic NC1 to induce rat glomerulonephritis models, in addition to cationic BSA for mouse nephropathy models. Chondrex, Inc. plans to provide reagents to induce rat and mouse AAV models in the future.

Please refer to Chondrex, Inc’s website for more information.
Nephritis - Rat Anti-Glomerular Basement Membrane Nephritis Models
Nephritis - Mouse Immune Complex Glomerulonephritis Induced by Cationic BSA 
Anti-collagen antibodies