EVIDENCE THAT FILAGGRIN IS A COMPONENT OF CORNIFIED CELL ENVELOPES INHUMAN PLANTAR EPIDERMIS

Cornified cell envelope (CE) is generated during the late stages of ep idermal differentiation and is made up of proteins covalently linked t ogether by transglutaminases. To determine whether filaggrin is a comp onent of this structure in humans, we analysed highly purified CE from plantar stratum corneum. An immunoelectron microscopy analysis showed specific binding of four different anti-(pro)filaggrin monoclonal ant ibodies to the surface of the CE, proved previously to be free of non- covalently linked proteins. Moreover, the anti-filaggrin activity of o ne of the antibodies was absorbed by preincubation with the plantar CE , as determined by ELISA. Convincingly, fragments of CE produced by pr oteolytic digestion of the structures were stained by this antibody on immunoblots. These data provide direct evidence that filaggrin is a c omponent of CE purified from human plantar stratum corneum. Cross-link ing between CE and the filaggrin-containing fibrous matrix may enhance the structural cohesion of the corneocytes and thus the resistance of the stratum corneum.