| Autor: |
Moura, Marta Casal, Thompson, Gwen E., Nelson, Darlene A., Fussner, Lynn A., Hummel, Amber M., Jenne, Dieter E., Emerling, Daniel, Volkmuth, Wayne, Fervenza, Fernando C., Kallenberg, Cees G.M., Langford, Carol A., McCune, Joseph W., Merkel, Peter A., Monach, Paul A., Seo, Philip, Spiera, Robert F., St. Clair, E. William, Ytterberg, Steven R., Stone, John H., Robinson, William H., Pang, Yuan-Ping, Specks, Ulrich |
| Jazyk: |
angličtina |
| Rok vydání: |
2019 |
| Předmět: |
|
| DOI: |
10.1101/549063 |
| Popis: |
Proteinase 3 (PR3) is the major antigen for anti-neutrophil cytoplasmic antibodies (ANCAs) in the systemic autoimmune vasculitis, granulomatosis with polyangiitis (GPA). PR3-targeting ANCAs (PR3-ANCAs) recognize different epitopes on PR3 and are thought to be pathogenic for the development of the necrotizing vasculitis. To identify epitopes recognized by PR3-ANCAs, we pursued a strategy based on human-murine chimeric PR3 mutants. Interestingly, rather than observing reduced binding of PR3-ANCAs to Epitope 5 on a PR3 mutant (iHm5-Val 103 ) with chimeric mutations in Epitope 5, we found substantially increased binding of the majority of PR3-ANCAs to iHm5-Val 103 compared with the PR3 mutant (iPR3-Val 103 ) clinically used to detect PR3-ANCAs. More interestingly, using iHm5-Val 103 we identified a monoclonal antibody (moANCA518) from a patient with GPA that bound selectively to iHm5-Val 103 . Inhibition experiments using epitope-specific monoclonal antibodies and their antigen-binding fragments mapped the binding sites of moANCA518 and PR3-ANCAs (from patients displaying preferential binding to iHm5-Val 103 over iPR3-Val 103 ) to Epitope 3 on iHm5-Val 103 , a mutation-free epitope located far from the mutation sites in Epitope 5. These results demonstrate that the selective binding of moANCA518 (and likely the preferential binding of PR3-ANCAs from patients) to iHm5-Val 103 is conferred by increased antigenicity of Epitope 3 on iHm5-Val 103 caused by distal mutations, indicating that PR3-ANCAs bind to epitopes of a folded antigen conducive to allosteric effects of mutations—a previously unrecognized characteristic with implications for studying antibody-mediated autoimmune diseases and novel treatment approaches. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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