Epidermolysis bullosa acquisita sera react with distinct epitopes on the NC1 and NC2 domains of type VII collagen: study using immunoblotting of domain-specific recombinant proteins and postembedding immunoelectron microscopy
ABSTRACT The sera of epidermolysis bullosa acquisita (EBA) react with type VII collagen, a major component of anchoring fibrils, in which the major epitopes have been considered to be present in the N-terminal noncollagenous (NC) 1 domain.
To determine whether there are also epitopes in the C-terminal NC2 domain, and to determine their ultrastructural localization.
Immunoblotting using recombinant proteins of the NC1 and NC2 domains of type VII collagen, and postembedding immunoelectron microscopy.
Twenty of 28 EBA sera tested reacted with the NC1 domain and eight sera reacted with the NC2 domain. The sera that reacted with the NC1 domain showed immunoreactivity within the lamina densa and the sera that reacted with the NC2 domain showed immunoreactivity in the dermis 300-360 nm below the lamina densa.
This study clearly identified the presence of epitopes in the NC2 domain, and showed that the epitope in the NC1 domain is present in the lamina densa and that the epitope in the NC2 domain is in the dermis below the lamina densa.
SourceAvailable from: Xiaoguang Li[Show abstract] [Hide abstract]
ABSTRACT: Mucous membrane pemphigoid (MMP) is a rare autoimmune bullous disease caused by various autoantibodies. This study aimed to evaluate the diagnostic value of MMP-specific autoantibodies in patient sera. We analyzed sera from 30 MMP-suspected patients with intractable oral mucosal lesions using a combination of indirect immunofluorescence with 1M NaCl-split skin, immunoblot analysis, and ELISAs. We also analyzed clinical features among different types of MMP. Seventeen, 4, and 3 patients were diagnosed with anti-BP180-type MMP, anti-laminin-332-type MMP, and combined anti-BP180/anti-laminin-332-type MMP, respectively. Our results indicated that a combination of immunologic testing for circulating autoantibodies is useful for the diagnosis of MMP.12/2013; 117(4). DOI:10.1016/j.oooo.2013.12.402
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ABSTRACT: Epidermolysis bullosa acquisita (EBA) is an autoimmune subepidermal blistering disease of mucous membranes and the skin caused by autoantibodies against collagen VII. In silico and wet laboratory epitope mapping studies revealed numerous distinct epitopes recognized by EBA patients' autoantibodies within the non-collagenous (NC)1 and NC2 domains of collagen VII. However, the distribution of pathogenic epitopes on collagen VII has not yet been described. In this study, we therefore performed an in vivo functional epitope mapping of pathogenic autoantibodies in experimental EBA. Animals (n = 10/group) immunized against fragments of the NC1 and NC2 domains of collagen VII or injected with antibodies generated against the same fragments developed to different extent experimental EBA. Our results demonstrate that antibodies targeting multiple, distinct epitopes distributed over the entire NC1, but not NC2 domain of collagen VII induce blistering skin disease in vivo. Our present findings have crucial implications for the development of antigen-specific B- and T cell-targeted therapies in EBA.Journal of Cellular and Molecular Medicine 08/2014; DOI:10.1111/jcmm.12338 · 3.70 Impact Factor