Induction of dermal-epidermal separation in mice by passive transfer of antibodies specific to type VII collagen

Abstract

Epidermolysis bullosa acquisita (EBA) is a subepidermal blistering disorder associated with tissue-bound and circulating autoantibodies specific to type VII collagen, a major constituent of the dermal-epidermal junction. Previous attempts to transfer the disease by injection of patient autoantibodies into mice have been unsuccessful. To study the pathogenic relevance of antibodies specific to type VII collagen in vivo, we generated and characterized rabbit antibodies specific to a murine form of this antigen and passively transferred them into adult nude, BALB/c, and C57BL/6 mice. Immune rabbit IgG bound to the lamina densa of murine skin and immunoblotted type VII collagen. Mice injected with purified IgG specific to type VII collagen, in contrast to control mice, developed subepidermal skin blisters, reproducing the human disease at the clinical, histological, electron microscopical, and immunopathological levels. Titers of rabbit IgG in the serum of mice correlated with the extent of the disease. F(ab′) 2 fragments of rabbit IgG specific to type VII collagen were not pathogenic. When injected into C5-deficient mice, antibodies specific to type VII collagen failed to induce the disease, whereas C5-sufficient mice were susceptible to blister induction. This animal model for EBA should facilitate further dissection of the pathogenesis of this disease and development of new therapeutic strategies.

Peptide mimetics of immunoglobulin A (IgA) and FcαRI block IgA‐induced human neutrophil activation and migration

“…The current general immunosuppressive treatment consisting of dapsone and corticosteroids causes several undesirable side effects systemically [7,8], and a more specific therapy is required. Since autoantibodies targeting skin proteins have been shown to be pathogenic in several mouse models [24][25][26][27][28][29][30][31][32], it is appealing to interfere with their binding or function. Removing autoantibody-immune complexes by immunoadsorption or immunoapheresis is consequently an attractive strategy [33,34], but this is an intensive treatment, since the patient's plasma needs to be filtered multiple times.…”

In vivo enzymatic modulation of IgG antibodies prevents immune complex‐dependent skin injury

“…In this model, repetitive injection of affinity-purified rabbit antibodies to murine COL7 into wild-type C57BL/6 mice, over a period of 12 days, results in a blistering phenotype closely mimicking inflammatory EBA. 19 To address the effect of IdeS treatment on blister formation in experimental EBA, we treated mice (n=4/group) with IdeS or PBS and, subsequently, injected them with rabbit IgG against murine COL7. Control mice developed initial blisters 4 days after the first injection of rabbit IgG to COL7, while widespread disease was observed 6 days after the first injection.…”

“…Total IgG from immunized rabbits (with murine COL7c) and normal rabbit sera was purified by affinity chromatography using protein G affinity as previously reported. 19 Next, murine COL7c-specific IgG was isolated from purified total IgG using Affi-Gel (Bio-Rad, Munich, Germany). For IgG was filter-sterilized (pore size, 0.22 μm; Sartorius), and protein concentration was adjusted to 2.0 mg/mL.…”

“…At day 12, all mice were sacrificed, blood was taken, and both lesional and perilesional skin biopsies were obtained and prepared for examination by histopathology and IF microscopy (to detect tissue-bound IgG and complement C3 deposits), as described. 19 For a better visualization of skin structures, a double staining for nuclear DNA via DAPI (4′,6-diamidino-2-phenylindole) (AppliChem PanReac, Darmstadt, Germany) was added to the IgG and C3 staining. Deposition of the Fc and F(ab') 2 fractions of pathogenic IgG at the basement membrane was visualized using FITC-conjugated goat anti-rabbit antibodies to IgG Fc and F(ab') 2 , respectively (DAKO, Glostrup, Denmark).…”

Epidermolysis bullosa acquisita

“…[29][30][31] Passive transfer mouse models using nude, BALB/c, C57BL/6 and SKH-1 mice have been developed by injecting mice with sera from immunized rabbits against murine or human recombinant NC1, which furthered the understanding of the pathogenic sequence of EBA in vivo. 32,33 Passively transferring the entire IgG fractions from human EBA patients induced blister formation in mouse skin. 34 These models showed that the neonatal Fc-receptor (FcRn), complement, activated neutrophils and reactive oxygen species (ROS) induce blister formation in EBA.…”