The antiproteolytic compound alpha 2-macroglobulin in human skin.

Monoclonal antibodies recognizing the antiproteolytic compound alpha 2-macroglobulin (MG) were used for immunohistological studies on normal human skin. MG-specific immunoreactivity was found to be localized to the papillary dermis and to be concentrated in the region of the epidermodermal junction. In view of these findings and the possible involvement of proteolytic enzymes and their inhibitors in blister formation, we asked whether MG occurs in the fluid of experimentally induced blisters. MG was identified (by western-blotting) and quantified (by a monoclonal antibody based enzyme immunoassay) in the fluid of experimentally induced suction blisters. Taken together, MG is present in such blister fluid in concentrations 6 times lower than in serum, but still in an antiproteolytic range. These findings allow suggestion of a possible role for the antiproteolytic compound MG in blister formation.