In cell-based laser tweezer experiments, TP prevented PV-IgG- or AK
23-induced reduction of Dsg3 bead binding but not PV-IgG-mediated loss of Dsg1
bead binding. The numbers of HaCaT surface-bound Dsg3 (black
bars) and Dsg1 beads (white bars) resisting laser beam
displacement were reduced by incubation with EGTA (5 mm, 30 min).
Incubation of monolayers with attached beads for 30 min with IgG fractions
from PV patients significantly reduced the number of bound Dsg3 and Dsg1
beads. However, preincubation with TP (20 μm) for 30 min
prevented AK 23-, PV-IgG 1-, and PV-IgG 2-induced reduction of Dsg3
(p = 0.00021, p = 0.01728, p = 0.03142,
respectively) but not reduction of Dsg1 bead binding (p = 0.5512,
p = 0.1311, for PV-IgG 1 and PV-IgG 2, respectively). Preincubation
with CP-2 (20 μm) did not alter PV-IgG-mediated loss in Dsg3
(p = 0.3522) and Dsg1 bead binding (p = 0.9688) (n
= 6 for each condition).