Detection of canine pemphigus foliaceus autoantigen by immunoblotting

The antigens targeted by autoantibodies in sera from canine patients with pemphigus foliaceus (PF) were detected by indirect immunofluorescence and Western immunoblotting. The extracted proteins from canine keratinocytes cultured in high-calcium condition for 48 h after confluency and from bovine nose epidermis were used as antigens in Western blotting. Canine keratinocytes cultured in high-calcium condition showed fluorescent deposits in intercellular spaces by incubation with sera from both canine and human pemphigus patients. By Western blotting, eight out of 16 canine PF sera recognised 160 kDa protein. 85 kDa and 120 kDa proteins were also recognised by four to five canine PF sera, respectively. The 160 kDa band, recognised by eight canine PF sera, had an identical mobility to the protein identified by a human PF serum. These results suggested that the autoantibodies in sera from canine PF recognised the 160 kDa desmosomal proteins, which may correspond to the desmoglein 1.