Use of western blot to study Microsporum canis antigenic proteins in canine dermatophytosis

Western blotting was used to describe the Microsporum canis proteins with antigenic activity in dogs with dermatophytosis. Electrophoretic separation of whole fungal strain extract cultured from a cat was performed under denaturing conditions. The proteins were blotted onto nitrocellulose and probed with sera collected from 22 dogs with dermatophytosis (18 M. canis, 3 M. gypseum, 1 Trichophyton mentagrophytes;group A), 20 dogs with skin diseases other than dermatophytosis, and 22 dogs with no clinical cutaneous signs (group B, n = 42). Nine principal IgG-binding proteins with apparent molecular weights of 180, 144, 130, 120, 102, 96, 80, 68, and 48 kD were visualised on group A blots. For these proteins, serological cross-reactivity with different strains of M. canis may be indirectly confirmed, whereas additional proteins were found to react with sera from individual dogs. The proteins visualised in this study may represent diagnostic markers of dermatophyte infection. The proteins should be further evaluated for their role in the cellular immune response of dogs with dermatophytosis.