A non-desmoglein component of bovine epidermis reactive with pemphigus foliaceus sera

A component from bovine epidermis has been purified and found to react with sera from patients with pemphigus foliaceus (PF). This component appears to have molecular weight characteristics similar to those of a previously reported component of human and bovine epidermis which was reactive with PF sera, but only detectable by radiolabeling. It is composed of an 80 kD and a 45 kD polypeptide which are thought to be covalently linked. By chromatographic data, the native form appears to be a noncovalently joined dimer of the 80 and 45 kD polypeptides. Amino acid analysis and sequence data indicate that the 80 kD component is not desmoglein (DG) nor any other known protein whose sequence is entered in data banks. Previous studies by Stanley indicate that DG is the major target of autoantibodies in PF sera. Our finding of another epidermal component reactive with PF antibodies raises some questions. It is not yet known if PF anti-DG antibodies cross-react with this new epidermal antigen or if these antibodies constitute separate and non-cross-reacting sets. Both possibilities and their ramifications are discussed.