Conformational epitope mapping of antibodies against desmoglein 3 in experimental murine pemphigus vulgaris.
BACKGROUND
Pemphigus vulgaris (PV) is a blistering skin disease caused by IgG autoantibodies against desmoglein 3 (Dsg3). We have recently developed an active disease mouse model for PV by adoptive transfer of splenocytes from immunized or naive Dsg3-/- mice into Rag2-/- recipient mice.


OBJECTIVE
In this study, we characterized the conformational epitopes of anti-Dsg3 IgG antibodies and their pathogenic activities in the PV model mice.


METHODS
The binding regions of anti-Dsg3 IgG antibodies were assessed by competition ELISAs with domain-swapped mouse Dsg1/Dsg3 molecules in PV model mice receiving immunized (n = 53) or naive (n = 56) splenocytes. To compare the pathogenic activity of antibodies against N-terminal versus C-terminal extracellular domains, Dsg3-/- mice were immunized with the residues 1-162 or the residues 403-565 of mouse Dsg3, and the splenocytes were adoptively transferred into Rag2-/- mice.


RESULTS
The middle to C-terminal extracellular domains of Dsg3 (residues 195-565) showed >50% competition in 51/53 (96.2%) and 45/56 (80.4%) while the N-terminal domain (residues 1-162) showed >50% competition only in 3/53 (5.7%) and 8/56 (14.3%) in mice receiving immunized and naive splenocytes, respectively. The mice receiving Dsg3-/- splenocytes immunized with the residues 403-565 developed the PV phenotype as early as and as severely as the mice receiving splenocytes immunized with the residues 1-162.


CONCLUSIONS
In PV model mice the antibodies were dominantly raised against the middle to C-terminal extracellular domains of mouse Dsg3 where amino acid sequences are less conserved among desmoglein isoforms and that those antibodies may also be involved in the blister formation.
Anzai
Hidemi
H
Department of Dermatology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan. hidemi-a@ta2.so-net.ne.jp
Fujii
Yoshiko
Y
Nishifuji
Koji
K
Aoki-Ota
Miyo
M
Ota
Takayuki
T
Amagai
Masayuki
M
Nishikawa
Takeji
T
D019264:Adoptive Transfer; D000818:Animals; D016367:Baculoviridae / Q000235:genetics; D015820:Cadherins / Q000235:genetics / Q000276:immunology; D002460:Cell Line; D003598:Cytoskeletal Proteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology*; D051183:Desmoglein 1; D051184:Desmoglein 3; D051182:Desmogleins; D051180:Desmoplakins; D018604:Epitope Mapping; D005822:Genetic Vectors; D007114:Immunization; D007074:Immunoglobulin G / Q000276:immunology; D007313:Insecta; D051379:Mice; D018345:Mice, Knockout; D010392:Pemphigus / Q000276:immunology* / Q000473:pathology; D010446:Peptide Fragments / Q000276:immunology; D010641:Phenotype; D017434:Protein Structure, Tertiary; D013154:Spleen / Q000166:cytology / Q000276:immunology; D013997:Time Factors; D014162:Transfection
D015820:Cadherins; D003598:Cytoskeletal Proteins; D051183:Desmoglein 1; D051184:Desmoglein 3; D051182:Desmogleins; D051180:Desmoplakins; C495299:Dsg1a protein, mouse; C495300:Dsg3 protein, mouse; D007074:Immunoglobulin G; D010446:Peptide Fragments