Abstract: Objective To investigate the pathogenic significance of antigenic epitopes and their relevant antibodies in pemphigus vulgaris (PV) by neonatal mouse model. Methods The extracellular domain 1-2 (EC1-2) fusion protein was expressed and purified by glutathione affinity chromatography on the basis of construction of recombinant EC1-2 vector, and then the New Zealand white rabbits were immunized to obtain the specific antisera. The IgG fraction was transferred into the neonatal mice passively after it was purified from the antisera. After 15-18 hours of injection, the abdomen skin and the sera of the mice were examined by light microscopy, electron microscopy, direct immunofluorescence and indirect immunofluorescence. Results In the evaluation of the study group of mice, the intraepithelial vesicle formation was observed. Electron microscopy showed that intercellular spaces were widened, desmosome split and disappeared. In immunofluorescence, the fluorescence-labeled IgG deposied between the acantholytic cells. In the control group of mice there were no pathogenic changes observed, except very weak fluorescence between intercellular spaces. Conclusion The PV mouse model established shows that the EC1-2 epitope in PVA antigen and its relevant antibodies were pathogenic, and can be used as a tool in studying the pathogenesis of PV.

Key words: Pemphigus, Pemphigus vulgaris antigen, Epitopes