Human autoantibodies against a desmosomal protein complex with a calcium-sensitive epitope are characteristic of pemphigus foliaceus patients.

Abstract

Pemphigus foliaceus (PF) patients have antibodies against a tightly, but noncovalently bound complex of polypeptides, which consists of desmoglein I (DGI) and other, possibly desmosomal, proteins. Most PF antibodies bind a calcium-sensitive epitope on this complex and chelation of calcium destroys the reactivity of these sera with the complex, but not the complex itself. The PF sera that do bind the desmosomal complex in the absence of calcium are those sera capable of binding denatured DGI on immunoblotting, and these same sera also immunoprecipitate only DGI when the desmosomal complex is dissociated with SDS. These findings demonstrate that autoantibodies against a complex of desmosome-associated proteins are characteristic of PF and define a calcium-sensitive conformational epitope on this complex.

Identification of pemphigus vulgaris antigen extracted from normal human epidermis and comparison with pemphigus foliaceus antigen.

“…These data indicate that some PV sera, in addition to having antibodies to the PV complex, have antibodies to a calcium-sensitive epitope on the PF complex. Similarly, we have previously shown that most PF sera also bind a calciumsensitive epitope on the PF complex (2).…”

“…Immunoprecipitations were performed as previously described (2,8,9,12) except that in most experiments 2 mM CaCl2 was added to all buffers and washing solutions. Approximately 20 X 106 cpm of 251I-labeled epidermal extracts or 4 X 106 cpm of '4C-labeled cultured keratinocyte extracts and 10-15 Al of sera were used per immunoprecipitation.…”

“…Precipitated polypeptides were resolved by SDS-PAGE or into two dimensions by isoelectric focusing followed by SDS-PAGE as previously described (3). Separated proteins were then visualized by autoradiography using enhancing screens (2).…”

“…Recently, using an immunoprecipitation procedure with extracts of normal human epidermis, we have shown that all PF patients have antibodies to a complex of polypeptides with a calcium-sensitive epitope (2). This complex (PF complex) consists of polypeptides of 260,000, 160,000 (desmoglein I), 10,000, and 85,000 apparent molecular weight.…”

Autoantibodies against the amino-terminal cadherin-like binding domain of pemphigus vulgaris antigen are pathogenic.

“…Disease control sera were obtained from patients with clinically and histologically typical pemphigus foliaceus (PF). PF is an autoimmune blistering disease of epidermis, in which autoantibodies bind DGI (26)(27)(28). These PF control sera showed characteristic immunofluorescence findings.…”