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Relationship between antigens and IgG subclasses in bullous pemphigoid
M Suzuki1, S Harada, K Kanazawa
1Department of Dermatology, Jichi Medical School, Tochigi, Japan.
Autoimmunity
|January 1, 1994
Summary
Bullous pemphigoid (BP) IgG subclasses, including IgG1, IgG2, and IgG4, may target the same epitope on the basement membrane zone antigen. Patient variations exist in antibody binding and complement fixation capabilities.
Area of Science:
- Immunology
- Dermatology
- Autoimmune Diseases
Background:
- Bullous pemphigoid (BP) is an autoimmune blistering disease.
- BP is characterized by antibodies to the basement membrane zone (BMZ).
- Previous work identified BP antibodies as IgG1, IgG2, and IgG4, with IgG1 fixing complement.
Purpose of the Study:
- To investigate if BP IgG subclasses bind to the same or different epitopes on the BMZ antigen.
- To analyze the epitope binding characteristics of different IgG subclasses in BP patients.
Main Methods:
- Inhibition immunofluorescence studies to assess complement fixation inhibition.
- Immunoblot analysis to determine antigen binding.
- Enzyme-linked immunosorbent assay (ELISA) to evaluate binding to synthetic peptides (P1-1 and P1-2).
- Inhibition ELISA to further characterize antibody interactions.
Main Results:
- Complement fixation by BP IgG1 was inhibited by IgG4 and partially by IgG2.
- Immunoblot analysis showed IgG1 and IgG4 binding to the same molecular weight (MW) antigen.
- ELISA revealed varied binding capabilities of IgG subclasses to synthetic peptides P1-1 and P1-2 across different BP patients.
- Inhibition ELISA indicated partial inhibition of IgG4 binding to P1-2 by IgG1 and IgG2.
Conclusions:
- BP IgG1, IgG2, and IgG4 subclasses can bind to the same epitope on the BP antigen.
- Significant inter-patient variability exists in the binding patterns and capabilities of these IgG subclasses.