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.

Caspase-1–Independent IL-1 Release Mediates Blister Formation in Autoantibody-Induced Tissue Injury through Modulation of Endothelial Adhesion Molecules

“…Subsequently, Fc-dependent mechanisms result in the formation of a proinflammatory milieu in the skin (31). Complement activation significantly (15,32,33), but not exclusively (34), contributes to the formation of this proinflammatory milieu. Finally, proteases, such as those released from skin-infiltrated inflammatory cells were seen in this study, and the induction of EBA led to increased endothelial ICAM-1 expression, which was absent if IL-1 function was blocked.…”

“…Rabbit anti-murine COL7 IgG was prepared as previously described (15). In brief, rabbits were immunized with recombinant proteins of the NC1 domain of murine COL7.…”

“…IgG from immune and normal rabbit sera were purified by affinity chromatography using protein G affinity. Passivetransfer studies into mice followed the published protocols (15,16). Each experiment was performed twice, using different anti-COL7 IgG preparations.…”

GM-CSF Modulates Autoantibody Production and Skin Blistering in Experimental Epidermolysis Bullosa Acquisita

“…Rabbit anti-mouse COL7 IgG was generated as described elsewhere (24). In brief, recombinant fragments of murine COL7 (termed mCOL7A, mCOL7B, and mCOL7C) tagged with GST were produced using a prokaryotic expression system and purified by glutathione affinity chromatography.…”

“…We selected epidermolysis bullosa acquisita (EBA) as a model, because the pathogenic relevance of autoantibodies in this disease has been clearly demonstrated (23)(24)(25), and induction of EBA has been described in a patient treated with GM-CSF (26). These autoantibodies are directed to type VII collagen (COL7), a major component of the hemidesmosomal adhesion complex of the dermal-epidermal junction (DEJ) (27,28).…”