系统性红斑狼疮中内皮细胞相关自身抗原的鉴定

目的在内皮细胞中筛选与系统性红斑狼疮(systemic lupus erythematosus,SLE)疾病相关的自身抗原。方法用免疫沉淀法以SLE病人血清中自身抗体捕获人脐带内皮细胞(human umbilical vein endothelial cell,HUVEC)相关抗原,并用双向电泳法分离免疫沉淀产物,然后用LC-MS-MS串联质谱鉴定与SLE病人血清反应的蛋白点。最后用Western blot法验证部分鉴定蛋白。结果相对于正常人血清对照,SLE病人血清捕获了多个内皮细胞相关蛋白,质谱鉴定结果显示:通过免疫沉淀与双向电泳结合的方法成功鉴定了包括GAPDH等已知SLE自身抗原在内的一系列蛋白,其中钙/钙调蛋白依赖性丝氨酸蛋白激酶(calcium/calmodulin-dependent serine protein kinase,CASK)为新发现SLE候选自身抗原。并以重组人CASK蛋白证实SLE病人血清中CASK抗体水平显著高于正常人对照。结论内皮细胞蛋白CASK可能作为一个新的SLE相关自身抗原。

Identification of autoantigens associated with systemic lupus erythematosus from endothelial cells

We aimed to identify new potential autoantigens associated with systemic lupus erythematosus(SLE) in human umbilical vein endothelial cells(HUVEC).Serum samples were collected from 27 SLE patients and 24 health donors.And IgG from serum was captured by Protein G Beads.Then the beads were washed and incubated with HUVEC lysate.The proteins which reacted with IgG-Beads were separated by immobilized pH gradient two-dimensional(2-D) gel electrophoresis,and the unique protein spots in SLE patients group were identified by LC-MS-MS.We identified several proteins including known SLE autoantigen GAPDH,in which calcium/calmodulin-dependent serine protein kinase(CASK) was the first find to be involved in SLE.Furthermore,we also found that CASK antibody expression in SLE was significantly higher than that in health donor.From all the results,we presumed that CASK in HUVEC may be a new potential autoantigen in SLE.