Identification of novel autoantigens using human IgG in SCID mice implanted with lacrimal and salivary grands from patients with Sjogren's Syndrome

干燥综合征（SS）是一种以外分泌腺慢性淋巴细胞浸润为特征的慢性自身免疫性疾病，是一种世界性疾病，在女性中发病率较高。唾液腺和泪腺是这种淋巴细胞浸润的主要目标，其结果是导致组织破坏和这些腺体的功能下降。但SS的病因和淋巴细胞浸润的机制尚不清楚。我们的项目的目的是识别特定的自身抗原导致疾病的发病机理和发展在党卫军和有用的血清学标志物的临床诊断SS。我们证明了植入nondisrupted件新鲜的唾液和泪从SS患者腺活检组织SCID小鼠的皮下组织导致高水平的人类免疫球蛋白(44 - 3426μg / ml)由gland-infiltrated B和浆细胞接种小鼠血清的20%用腺体活检组织。利用含人IgG的SCID小鼠血清，对两种人涎腺上皮细胞系（HSG和HSY）和正常人下颌下大组织cDNA文库进行cDNA表达克隆分析，以鉴定新的自身抗原作为血清学标记。编码SS- a /Ro和SS- b /La （SS自身抗体的主要靶点）的克隆分离到的噬菌体克隆最多。为了进一步筛选SS特异性自身抗原，我们利用SS患者和健康人的血清进行了血清学筛选。SS患者血清中针对5种新分离的自身抗原的IgG自身抗体的频率在30% ~ 45%之间，显著高于健康人血清。这些结果表明，我们使用SCID小鼠的方法可能允许鉴定新的特异性自身抗原作为临床诊断SS的血清学标记物。

Sjogren's syndrome (SS) is a chronic autoimmune disease characterized by chronic lymphocytic infiltration of the exocrine glands and a worldwide disease with higher prevalence in woman. The salivary and lacrimal glands are the main targets of this lymphocytic infiltration, which as a consequence leads to tissue destruction and decreased function of these glands. But the etiology of SS and mechanisms of lymphocytic infiltration is unknown. The purpose of our project was the identification of specific autoantigens contributing to the disease pathogenesis and progression in SS and useful serological markers for the clinical diagnosis of SS. We demonstrated that the implant of nondisrupted pieces of fresh salivary and lacrimal glands biopsy tissue from patients with SS into the subcutis of SCID mice results in high levels of human IgG (44-3,426μg/ml) produced by gland-infiltrated B and plasma cells in the sera of 20 % mice inoculated with gland biopsy tissue. Using the sera including human IgG from these SCID mice, we demonstrated the cDNA expression cloning analysis with two human salivary gland epithelial cell lines (HSG and HSY) and normal human submandibular grand tissue cDNA libraries in order to identify novel autoantigens as serological marker. The clone encoded SS-A/Ro and SS-B/La, known as a major target of autoantibodies in SS, had the most phage clones isolated by this analysis. To further select the specific autoantigens in SS, we carried out serological screenings using the sera of patients with SS and healthy individuals. Frequencies of IgG autoantibodies against five newerly isolated autoantigens in the sera of patients with SS showed between 30 % and 45 % in significantly higher amounts than in sera from healthy individuals. These results were suggested that our approach using SCID mice may allow the identification of novel specific autoantigens as serological markers for the clinical diagnosis of SS.