Bullous pemphigoid antigen: isolation from normal human skin

Area of Science:

• Immunodermatology
• Protein Biochemistry
• Autoimmune Blistering Diseases

Background:

• Bullous pemphigoid is an autoimmune blistering disease targeting the dermal-epidermal junction.
• Identification and characterization of disease-specific antigens are crucial for understanding pathogenesis and developing diagnostics.

Purpose of the Study:

• To isolate and characterize a protein antigen from epidermal PBS-soluble extracts.
• To evaluate the antigen's ability to block bullous pemphigoid antibody binding.
• To determine the presence of this antigen in various biological fluids.

Main Methods:

• Protein isolation using gel filtration (Bio-Gel A-1.5m) and ion exchange chromatography (DEAE-cellulose).
• Immunoelectrophoresis (IEP) and disc electrophoresis for protein characterization.
• SDS-PAGE to determine molecular weights.
• Indirect immunofluorescence blocking assays.

Main Results:

• A protein, designated A-1-Epid, was purified and characterized.
• A-1-Epid showed a single cathodal arc on IEP and a single band on disc electrophoresis.
• SDS-PAGE revealed two bands with molecular weights of 20,000 and 9,200 Da.
• Purified A-1-Epid blocked bullous pemphigoid antibody staining on monkey esophagus and human skin.
• A-1-Epid and a second antigen (A-2-Epid) were found in esophageal mucosa, saliva, and urine.

Conclusions:

• The purified bullous pemphigoid antigen (A-1-Epid) is a distinct epidermal protein.
• A-1-Epid plays a role in the basement membrane zone targeted by bullous pemphigoid antibodies.
• The antigen's presence in various bodily fluids suggests potential for diagnostic applications.