Epidermolysis bullosa acquisita sera react with distinct epitopes on the NC1 and NC2 domains of type VII collagen: study using immunoblotting of domain-specific recombinant proteins and postembedding immunoelectron microscopy.
BACKGROUND
The sera of epidermolysis bullosa acquisita (EBA) react with type VII collagen, a major component of anchoring fibrils, in which the major epitopes have been considered to be present in the N-terminal noncollagenous (NC) 1 domain.


OBJECTIVE
To determine whether there are also epitopes in the C-terminal NC2 domain, and to determine their ultrastructural localization.


METHODS
Immunoblotting using recombinant proteins of the NC1 and NC2 domains of type VII collagen, and postembedding immunoelectron microscopy.


RESULTS
Twenty of 28 EBA sera tested reacted with the NC1 domain and eight sera reacted with the NC2 domain. The sera that reacted with the NC1 domain showed immunoreactivity within the lamina densa and the sera that reacted with the NC2 domain showed immunoreactivity in the dermis 300-360 nm below the lamina densa.


CONCLUSIONS
This study clearly identified the presence of epitopes in the NC2 domain, and showed that the epitope in the NC1 domain is present in the lamina densa and that the epitope in the NC2 domain is in the dermis below the lamina densa.
Ishii
N
N
Department of Dermatology, Kurume University School of Medicine, 67 Asahimachi, Kurume, Fukuoka 830-0011, Japan.
Yoshida
M
M
Hisamatsu
Y
Y
Ishida-Yamamoto
A
A
Nakane
H
H
Iizuka
H
H
Tanaka
T
T
Hashimoto
T
T
D024143:Collagen Type VII / Q000276:immunology*; D016107:Epidermolysis Bullosa Acquisita / Q000276:immunology* / Q000473:pathology; D000939:Epitopes / Q000032:analysis / Q000276:immunology*; D006801:Humans; D015151:Immunoblotting; D016253:Microscopy, Immunoelectron; D011994:Recombinant Proteins / Q000276:immunology; D012867:Skin / Q000276:immunology / Q000648:ultrastructure
D024143:Collagen Type VII; D000939:Epitopes; D011994:Recombinant Proteins