Figure 3. In vitro and in vivo pathogenic activity of anti-DSG3 antibodies.

(A) Representative keratinocyte dissociation experiment. Primary human keratinocytes were seeded to confluence, and mAb PVA224 and a control antibody were added (1–10 μg/ml), followed by addition of ETA to cleave DSG1 molecules. Cells were incubated with dispase I to detach the monolayer from the plate, and sheet fragments were fixed and stained using crystal violet. (B) Keratinocyte dissociation induced by different antibodies. Shown is the dissociation index determined as specified in Methods in duplicate cultures in 2 independent experiments (mean ± SEM). (C–E) Macroscopic blisters (black arrows) (C), intraepidermal suprabasal blistering and acantholysis (D), and intercellular deposition of human IgG in the epidermis (E) induced by injection into newborn mice of the indicated antibodies coadministered with ETA. Data are representative of results obtained from groups of 5 mice. Original magnification, ×200.