An attempt to develop mouse model for anti-laminin γ1 pemphigoid

Background: We recently reported that the autoantibodies of anti-p200 pemphigoid sera react with laminin gamma 1 and renamed this entity as anti-laminin pemphigoid. However, it has not been clarified whether the anti-laminin gamma 1 autoantibodies, particularly those to the C-terminal integrin binding site, affect the dermoepidermal junction and cause subepidermal blisters. Objective: The aim of this study was to develop animal models for anti-laminin gamma 1 pemphigoid. Methods: We attempted to produce two mouse models for anti-laminin gamma 1 pemphigoid; (1) a passive transfer model: injection of rabbit IgG to shorter bacterial recombinant protein of the murine laminin gamma 1 C-terminal 107 amino acids, and (2) an active disease model: direct immunization to mice with this recombinant protein. Results: Immunoblotting revealed that 70% of patient sera reacted with the shorter recombinant protein of human laminin gamma 1 C-terminus. In the passive transfer model, rabbit IgG to the murine laminin gamma 1 C-terminus was deposited, without C3 deposition, at the epidermal basement membrane zone. In contrast, in the active disease model, direct immunofluorescence of mouse skin sections showed no deposition of either murine IgG or C3. Blister formation was not seen in either model both phenotypically and histopathologically. Conclusion: In the two different mouse animal models for anti-laminin gamma 1 pemphigoid, although rabbit IgG to the recombinant laminin gamma 1 C-terminus bound to the epidermal basement membrane zone in passive transfer model, no obvious blister formation was seen. To reproduce skin lesions in mouse models for anti-laminin gamma 1 pemphigoid, further improvement should be needed. (C) 2013 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.