CONFORMATIONAL EPITOPES OF PEMPHIGUS ANTIGENS (DSG1 AND DSG3) ARE CALCIUM-DEPENDENT AND GLYCOSYLATION INDEPENDENT

Citation
M. Amagai et al., CONFORMATIONAL EPITOPES OF PEMPHIGUS ANTIGENS (DSG1 AND DSG3) ARE CALCIUM-DEPENDENT AND GLYCOSYLATION INDEPENDENT, Journal of investigative dermatology, 105(2), 1995, pp. 243-247
Citations number
30
Categorie Soggetti
Dermatology & Venereal Diseases
ISSN journal
0022202X
Volume
105
Issue
2
Year of publication
1995
Pages
243 - 247
Database
ISI
SICI code
0022-202X(1995)105:2<243:CEOPA(>2.0.ZU;2-N
Abstract
The target molecule of pemphigus autoantibodies is a transmembrane des mosomal component, desmoglein 3 (Dsg3) in pemphigus vulgaris (PV) and Dsg1 in pemphigus foliaceus (PF). In this study, we examined the effec ts of calcium and glycosylation on the antigenicity of the pemphigus a ntigens and on the generation of conformational epitopes. We used reco mbinant baculovirus proteins, PVIg and PFIg, which are considered to r eflect accurately the native conformation of the extracellular domain of their respective proteins Dsg3 and Dsg1. These baculoproteins could immunoadsorb heterogeneous autoantibodies from the corresponding sera of PV and PF patients, completely blocking indirect immunofluorescenc e staining of normal human skin. Chelating calcium from the solution c ontaining the baculoproteins using ethylenediaminetetraacetic acid (ED TA) or ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraaceti c acid (EGTA) abolished immunoadsorption by both PVIg and PFIg; howeve r, immunoadsorption by the baculoproteins was restored after dialysis against 1 mM calcium. Nonglycosylated forms of both baculoproteins pro duced in the presence of tunicamycin retained their immunoadsorptive a bility. Furthermore, immunoadsorption by the baculoproteins was preven ted irreversibly by treatment with low pH, high pH, and boiling, but n ot with the non-ionic detergent Nonidet P-40. These findings indicate that formation of the conformational epitopes on the pemphigus antigen s is dependent on calcium but independent of glycosylation, and provid e direct evidence that calcium plays an important role in determining the antigenic properties of the pemphigus antigens.