DEMONSTRATION OF ANTIBODIES TO BOVINE DESMOCOLLIN ISOFORMS IN CERTAINPEMPHIGUS SERA

We have shown previously that IgG antibodies in certain pemphigus sera , particularly endemic Brazilian pemphigus foliaceus (BPF) sera, react with bovine desmocollins (Dsc), which are transmembranous glycoprotei ns of desmosome junctions. Desmocollins occur as three different isofo rms (Dsc 1, 2 and 3), all of which are represented in the epidermis. I n this study, we examined sera of various pemphigus types by immunoblo tting purified bovine desmosomes and bovine Dsc 1, 2 and 3 fusion prot eins, expressed in pGEX expression vectors. Six of 15 (40.0%) BPF sera , two of 18 (11.1%) non-endemic pemphigus foliaceus sera, eight of 39 (20.5%) pemphigus vulgaris (PV) sera, and two of 11 (18.2%) normal ser a, showed reactivity with Dsc from desmosomes. Experiments with fusion proteins showed that no Dsc isoform was specifically recognized by se ra of any individual pemphigus type. Our results indicate that the pat hogenesis of pemphigus might be more complex than previously believed.