寻常型天疱疮抗原EC1-2表位的致病性

The Pathogencity of EC1-2 Epitope in Pemphigus Vulgaris Antigen

目的通过寻常型天疱疮新生鼠模型的建立研究寻常型天疱疮抗原(PVA)致病性表位及其相应抗体的致病作用。方法构建重组PVA细胞外区(EC)1-2片段分子。经亲和层析纯化后,免疫家兔,得到兔抗PVAEC1-2融合蛋白的抗血清。将提纯IgG抗体成分,被动转移到BALB/c新生鼠,15～18h后对新生鼠皮肤、血清进行组织病理、电镜和免疫荧光检查。结果在对实验组新生鼠的评价中,其组织病理示表皮内水疱形成,棘细胞间棘突消失,棘层松解;电镜示棘细胞间距离增宽,桥粒分离、溶解、消失;DIF和IIF均示棘细胞间免疫荧光沉积。而对照组小鼠除了IIF示棘细胞间微弱的荧光沉积外,其余检查均正常。结论通过寻常型天疱疮新生鼠模型的建立,证明PVA分子中EC1-2表位为致病性表位,其相应的抗体为致病性抗体。另外,PVA重组分子的构建,新生鼠模型的建立为天疱疮以及其它自身免疫性疾病的诊断和治疗提供了一个模型。

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.