Figure 6.
Dermal-epidermal separation is dependent on the Fc portion of autoantibodies to type VII collagen. Patient’s autoantibodies, which had been purified against recombinant NC1 of type VII collagen, were subsequently subjected to pepsin digestion. Resulting F(ab′)2 fragments labeled the dermal side of 1 mol/L of NaCl-split skin by indirect IF microscopy using an anti-Fab fluorescein isothiocyanate-conjugated secondary antibody (a), whereas no staining was observed using a Fc-specific conjugate (b). F(ab′)2 fragments failed to induce blisters (c), in contrast to unfragmented autoantibodies to type VII collagen (d). Scale bar, 40 μm.