Relationship between antigens and IgG subclasses in bullous pemphigoid.
Bullous pemphigoid (BP) is an autoimmune blistering disease characterized in part by the presence of tissue-bound and circulating antibodies (mostly of IgG) to the basement membrane zone (BMZ). We previously reported that IgG subclasses of BP antibodies were IgG1, IgG2 and IgG4, and that only BP IgG1 fixed complements. In this study, we examined whether BP IgG sub-classes bound to the same epitope of BP antigen or a different epitope. In an inhibition immunofluorescence studies, the complement fixing capability of IgG1 was inhibited by the pretreatment with IgG4 and partially inhibited by IgG2. On immunoblot analysis, IgG1 and IgG4 were bound to the same MW of BP antigen. In enzyme-linked immunosorbent assay (ELISA), the binding capability of IgG subclass fractions from patients with BP to synthetic peptide P1-2, exceeding normal IgG subclass fractions was seen in five IgG1, one IgG2 and two IgG4, from eight BP patients. The binding capability of IgG subclass fractions from the patients with BP to P1-1, exceeding the normal IgG fractions was seen in two IgG1, three IgG2 and one IgG4 from ten BP patients. On inhibition ELISA, the binding activity to P1-2 of IgG4 was partially inhibited by the pretreatment of IgG1 and IgG2. These findings suggest that BP IgG1, IgG2 and IgG4 could bind to the same epitope though considerable variation occurred between patients.
Suzuki
M
M
Department of Dermatology, Jichi Medical School, Tochigi, Japan.
Harada
S
S
Kanazawa
K
K
Kitajima
Y
Y
Yaoita
H
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal; D001324:Autoantigens / Q000276:immunology*; D002352:Carrier Proteins; D002460:Cell Line; D003094:Collagen; D003598:Cytoskeletal Proteins; D000071821:Dystonin; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D015151:Immunoblotting; D007074:Immunoglobulin G / Q000145:classification / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009419:Nerve Tissue Proteins; D024041:Non-Fibrillar Collagens; D010391:Pemphigoid, Bullous / Q000276:immunology*; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000276:immunology; D012867:Skin / Q000276:immunology; D000097805:Collagen Type XVII
D000911:Antibodies, Monoclonal; D001324:Autoantigens; D002352:Carrier Proteins; D003094:Collagen; D003598:Cytoskeletal Proteins; D000071821:Dystonin; D007074:Immunoglobulin G; D009419:Nerve Tissue Proteins; D024041:Non-Fibrillar Collagens; D010446:Peptide Fragments; D000097805:Collagen Type XVII; C486268:DST protein, human