Cloning of Hamster Type XVII Collagen cDNA, and Pathogenesis of Anti-Type XVII Collagen Antibody and Complement in Hamster Bullous Pemphigoid

Abstract

Bullous pemphigoid is an inflammatory subepidermal blistering skin disease associated with an IgG autoimmune response to the type XVII collagen. The immunopathologic features of bullous pemphigoid can be reproduced in mice by the passive transfer of anti-type XVII collagen antibodies. In this model, it is thought that blister formation depends upon complement activation, neutrophil recruitment, and some proteolytic enzymes. In this study, we cloned hamster type XVII collagen cDNA, which contains a 4296 bp coding region and which is predicted to be a transmembrane protein with an extracellular collagenous domain, residing in type II orientation. Antipeptide antibodies (anti-1191 IgG) were obtained against a segment of hamster type XVII collagen homologous with the human type XVII collagen autoantibody-reactive site. The antipeptide antibodies were passively transferred to neonatal Syrian hamsters. The injected hamsters developed a microscopic subepidermal blister as seen previously in the mice. In order to test whether antigen-antibody complexes and complement initiate the subepidermal blister formation, we carried out experiments in vitro on condition that inflammatory cells were completely eliminated. Complement activation in sera was inhibited either by heating (at 56 degrees C for 30 min) or by preincubating with cobra venom factor. When the hamster skin was incubated with fresh anti-1191 antisera, separation of dermal-epidermal junction was observed. The anti-1191 IgG failed to induce C3 deposition and dermal-epidermal junction separation, however, if the anti-1191 IgG was added alone or complement activation in sera was inhibited. Under these conditions, IgG but not C3 was deposited on the basement membrane. These results strongly suggest that antigen-antibody complexes and complement initiate dermal-epidermal junction separation.

Repetitive Immunization Breaks Tolerance to Type XVII Collagen and Leads to Bullous Pemphigoid in Mice

“…These observations closely resemble the histopathological findings in human BP (28). Of note, eosinophilic infiltration in lesional skin, a hallmark of human BP, is not present in other IgG-mediated experimental models of BP (12)(13)(14)(15)(18)(19)(20). In contrast, eosinophilic infiltration has been observed in IgE-mediated mouse models of BP (16,17).…”

“…Evidence for the functional relevance of human anti-BP180 NC16A Abs was derived from the observations that serum levels paralleled disease activity in BP patients (10), and human BP180 NC16A-specific IgG induced subepidermal splits in cryosections of human skin (11). To obtain a better understanding of the pathogenesis and for evaluation of novel therapeutic strategies, autoantibody reactivity against BP180 has been explored in various experimental animal models mimicking the human disease, mostly by transfer of anti-BP180 autoantibodies in neonatal rodents (12)(13)(14)(15)(16)(17)(18)(19)(20). However, no model has been available in which tolerance to BP180 has been lost and in which clinical disease was present in immunocompetent animals over a prolonged time period.…”

What’s new in blistering disorders?

“…Liu et al [38] showed that when rabbit IgG directed against the NC16A of BP180 was passively transferred to mice, the mice developed disease both histologically and clinically similar to BP. Further work by Yamamoto et al [39] yielded similar results in hamsters. This process is also complement dependent, with deposits of IgG and complement factors found at the BMZ.…”

Increased Expression of Matrix Metalloproteinase-2, Matrix Metalloproteinase-9 and Matrix Metalloproteinase-13 in Lesional Skin of Bullous Pemphigoid

“…Liu et al [14,15,16,17,18,19,20,21]developed an IgG passive transfer mouse model of BP by administrating rabbit antimurine BP180 antibodies to neonatal mice. Yamamoto et al [22 ]demonstrated that the antigen-antibody complex and complement initiate dermal-epidermal junction separation using the hamster model of BP. The proposed mechanism of blister formation in experimental BP includes binding of anti-BP180 antibodies, complement activation, mast cell degranulation, neutrophil infiltration and activation.…”