Immunization with desmoglein 3 induces non-pathogenic autoantibodies in mice

Abstract

Background Pemphigus vulgaris (PV) is a rare autoimmune blistering disease characterized by the development of autoantibodies targeting desmoglein (Dsg) 3, but also against Dsg1 in mucocutaneous disease. Given that existing PV animal models only recapitulate aspects of the disease, we aimed to establish a more comprehensive disease model based on the immunization of mice with PV autoantigen(s). Methods The following immunization strategies were tested: (i) C57Bl/6J, B6.SJL-H2s C3c/1CyJ, DBA2/J, or SJL/J mice were immunized with recombinant murine Dsg3 (mDsg3), (ii) DBA2/J and SJL/J mice were immunized with mDsg3 and additionally injected a single non-blister inducing dose of exfoliative toxin A (ETA), and (iii) DBA2/J and SJL/J mice were immunized with human Dsg (hDsg) 1 and 3. Results Despite the induction of autoantibodies in each immunization protocol, the mice did not develop a clinical phenotype. Tissue-bound autoantibodies were not detected in the skin or mucosa. Circulating autoantibodies did not bind to the native antigen in indirect immunofluorescence microscopy using monkey esophagus as a substrate. Conclusion Immunization with PV autoantigens induced non-pathogenic Dsg1/3 antibodies, but did not cause skin/mucous membrane disease in mice. These findings, confirmed by failure of binding of the induced autoantibodies to their target in the skin, suggest that the autoantibodies which were formed were unable to bind to the conformational epitope present in vivo.

Immunostimulatory effects of Toll‐like receptor ligands as adjuvants in establishing a novel mouse model for pemphigus vulgaris

“…However, they did not test the pathogenicity of the serum from recipient mice, including the presence of antibodies recognizing native Dsg3 19 . Notably, the adjuvants used in these studies were CFA, alum, 15,19 TiterMax 18 or unspecified 11 . We believe that the recent availability of vaccine adjuvants with excellent immune‐activation capabilities opens up possibilities for inducing Dsg3‐specific autoimmune responses.…”

“…Previous studies demonstrated that antibodies induced by immunization with rDsg3 in wild-type mice, constrained by immune tolerance, failed to produce pathogenic antibodies capable of recognizing native Dsg3. [15][16][17][18] Notably, the adjuvants used in these studies were complete Freund's adjuvant (CFA), alum, 15,17,19 squalenebased TiterMax 18 or unspecified. 11 Although CFA based on mycobacteria remains the most potent immunopotentiator reported to date, 20 we believe that the recent availability of vaccine adjuvants with excellent immune-activation capabilities opens up possibilities for inducing Dsg3-specific autoimmune responses.…”

“…Therefore, a clear need exists for novel PV animal models that exhibit overactivated yet controllable immune responses, addressing these limitations and providing a more comprehensive understanding of PV pathogenesis and the development of therapeutic interventions. Previous studies demonstrated that antibodies induced by immunization with rDsg3 in wild‐type mice, constrained by immune tolerance, failed to produce pathogenic antibodies capable of recognizing native Dsg3 15–18 . Notably, the adjuvants used in these studies were complete Freund's adjuvant (CFA), alum, 15,17,19 squalene‐based TiterMax 18 or unspecified 11 .…”

Mouse models of pemphigus: valuable tools to investigate pathomechanisms and novel therapeutic interventions

“…Recent endeavors to break tolerance against Dsg3 in various strains of Dsg3-expressing mice employing different immunization protocols with recombinant human and murine Dsg3/Dsg1 forms did not elicit a clinical phenotype while non-pathogenic anti-Dsg3/Dsg1 IgG was induced ( 115 ). However, unpublished work currently focuses on the establishment of a Dsg3-transgenic mouse model displaying the formation of HLA-dependent antigen-specific T and B cells as well as a solid antigen-specific IgG as a basis of a lasting clinical phenotype.…”

The human skin organ culture model as an optimal complementary tool for murine pemphigus models

“…This approach was taken because immunization of wild-type mice expressing Dsg3 does not lead to in vivo pathogenic autoantibodies. [46][47][48] Within a few days, autoantibody production is noted in the Rag2 -/recipient mice, which are maintained without further immunizations for six months. While lesions develop within 7-14 days after transfer, weight loss was evident mainly due to blisters in the oral mucosa, which was severe in some mice and caused their death.…”