Induction of Complement-Fixing Autoantibodies against Type VII Collagen Results in Subepidermal Blistering in Mice

Abstract

Experimental models reproducing an autoimmune response resulting in skin blistering in immunocompetent animals are lacking. Epidermolysis bullosa acquisita (EBA) is a bullous skin disease caused by autoantibodies to type VII collagen. In this study, we describe an active disease model of EBA by immunizing mice of different strains with murine type VII collagen. All mice developed circulating IgG autoantibodies that recognized type VII collagen and bound to the lamina densa of the dermal-epidermal junction. Importantly, subepidermal blisters developed in 82% of SJL-1, 56% of BALB/c mice, and 45% of FcγRIIb-deficient mice, but not in SKH-1 mice. In susceptible animals, deposits of IgG1, IgG2, and complement C3 were detected at the dermal-epidermal junction. In contrast, in the nondiseased mice, tissue-bound autoantibodies were predominantly of the IgG1 subclass and complement activation was weak or absent. This active disease model reproduces in mice the clinical, histopathological, and immunopathological findings in EBA patients. This robust experimental system should greatly facilitate further studies on the pathogenesis of EBA and the development of novel immunomodulatory therapies for this and other autoimmune diseases.

Controlled tetra-Fc sialylation of IVIg results in a drug candidate with consistent enhanced anti-inflammatory activity

“…We also used an Fcγ receptor-dependent skin-blistering disease caused by collagen type VII-specific autoantibodies (36) to evaluate the efficacy of s4-IVIg. Prophylactic dosing with IVIg between 0.1 and 1 g/kg at the onset of the disease (day 4) resulted in a clear dose-response within this dose range, which was measured by the percentage of affected body area (Fig.…”

B Cells, Dendritic Cells, and Macrophages Are Required To Induce an Autoreactive CD4 Helper T Cell Response in Experimental Epidermolysis Bullosa Acquisita

“…Sections were observed by fluorescence microscopy (Keyence, Osaka, Japan). Neutrophil infiltration in the skin was detected by immunohistochemistry (IHC) as described earlier with modifications (20). Sixmicrometer frozen skin sections were incubated with biotin-conjugated Ly-6G (1:200 dilution) Ab at 37˚C for 1 h. Subsequently, sections were incubated with Ultra-Sensitive ABC Peroxidase Staining Kit (Thermo Scientific Pierce Protein Research Products) at room temperature (RT) for 0.5 h and were developed by 3,39-diaminobenzidine (Merck, Darmstadt, Germany).…”

“…Regarding the cellular requirements of autoantibody production, these models clearly documented a dependency on both B cells and CD4 T cells (15)(16)(17)(18). In principle, immunizationinduced models of AIBD (19)(20)(21) allow for investigating the cellular and molecular requirements that lead to loss of tolerance and subsequent autoantibody production. Yet, so far, detailed investigations on the cellular requirements in the early pathogenesis of these animal models had not been performed.…”

Clinical features and diagnosis of epidermolysis bullosa acquisita

“…In addition, IgA antitype VII collagen reactivity, either exclusively or in combination with IgG autoantibodies, is observed in 50-60% of patients [26,27,66]. The pathogenic relevance of antibodies against type VII collagen has clearly been shown in several in vivo and in vitro models [67][68][69][70][71] reviewed in [6]. Incubation of cryosections of normal human skin with sera of EBA patients followed by incubation with neutrophils from healthy volunteers leads to dermal-epidermal split formation [69].…”

“…the antitype VII collagen-mediated tissue destruction. To investigate the loss of tolerance to type VII collagen, mice were immunized with recombinant fragments of NC1 domain, which raised murine antitype VII collagen IgG that resulted in a long-lasting autoimmune skin disease resembling human EBA [68,74]. These animal models were subsequently used to show the pathogenic relevance of complement activation at the epidermal BMZ, neutrophils, CD18-mediated extravasation, FcγRIV, heat-shock protein 90, the glycosylation status of antitype VII collagen IgG, IL-1β, IL-6, GM-CSF, Erk 1/2, CXCL1/2, p38, Akt, RORa, HSP90, gene expression in myeloid cells, and the skin microbiome [75][76][77][78][79][80][81][82][83][84].…”