We reproduced an in vitro model of staphylococcal scalded skin syndrome or bullous impetigo in human skin explants in culture, using partially purified staphylococcal exfoliative toxin A (ETA). ETA affects epidermal antigens such as keratins, involucrins, epidermal growth factor, epidermal growth factor receptor, HLA-DR, ICAM-1 and TNF-α were observed using the appropriate monoclonal antibodies. However, expressions of these antigens on cultured skin explants were not influenced by treatment with ETA compared to the controls without ETA treatment. 160kD desmoglein I is known to have an important role in attaching epidemal cells and is the target antigen of pemphigus foliaceus (PF) antibody. We examined the effect of ETA on the binding of PF antibody to 160kD desmoglein I by indirect immunofluorescence, using a PE patient's serum. The intensity of the fluorescence of the bound antibody was clearly reduced by ETA pretreatment. The binding of pemphigus vulgaris antibody did not seem to be influenced by ETA pretreatment. ETA did not have any effect on the binding of pemphigoid antibody to the basement membrane zone.
These results suggest that the binding site of ETA is closely related to PF antigen (desmoglein I) and that the epidermolysis by ETA occurs without involvement of cellular or humoral factors in the host.
