Zieve Gary W, Khusial Permanan R
Department of Pathology, SUNY Stony Brook, Stony Brook, NY 11794-8691, USA.
Autoimmun Rev. 2003 Sep;2(5):235-40. doi: 10.1016/s1568-9972(03)00018-1.
Anti-Sm antibodies are found in greater than 30% of the patients with systemic lupus erythematosus (SLE) and are diagnostic of SLE. The Sm autoantigens are the small nuclear ribonucleoprotein (snRNP) common core proteins. The seven core proteins, B, D1, D2, D3, E, F and G, shared by a majority of the snRNP particles, form a heptamer ring approximately 20 nm in diameter, with the snRNA passing through the center. The Sm epitopes are distributed on the outside surface of the ring. A repeated proline rich motif with homology to an Epstein bar nuclear antigen in the B protein and a gly-arg-gly motif including a symmetrical dimethylarginine post translational modification in the B, D1 and D3 proteins are major Sm epitopes. The anti-Sm response has features typical of an antigen driven immune response. SnRNP proteins share several characteristics with other autoantigens including their assembly into ribonucleoprotein particles, homologies to known viral proteins, presence of post translational modifications, a high abundance and great stability and the presence of repeated motifs. Current work on the snRNP particles is attempting to identify the features that predispose the common core proteins to become autoantigens in vulnerable individuals.
抗Sm抗体在超过30%的系统性红斑狼疮（SLE）患者中被发现，是SLE的诊断依据。Sm自身抗原是小核核糖核蛋白（snRNP）的共同核心蛋白。大多数snRNP颗粒共有的七种核心蛋白，即B、D1、D2、D3、E、F和G，形成一个直径约20纳米的七聚体环，snRNA穿过中心。Sm表位分布在环的外表面。B蛋白中与EB病毒核抗原具有同源性的富含脯氨酸的重复基序，以及B、D1和D3蛋白中包含对称二甲基精氨酸翻译后修饰的甘氨酸-精氨酸-甘氨酸基序是主要的Sm表位。抗Sm反应具有抗原驱动免疫反应的典型特征。SnRNP蛋白与其他自身抗原具有几个共同特征，包括它们组装成核糖核蛋白颗粒、与已知病毒蛋白的同源性、翻译后修饰的存在、高丰度和高稳定性以及重复基序的存在。目前关于snRNP颗粒的研究正试图确定使共同核心蛋白在易患个体中成为自身抗原的特征。
