Gitlits V M, Sentry J W, Matthew L S, Smith A I, Toh B H
Department of Pathology and Immunology, Monash Medical School, Prahran, Victoria, Australia.
J Investig Med. 2001 May;49(3):276-83. doi: 10.2310/6650.2001.33973.
We report the identification and characterization of a novel 74-kd brain-specific autoantigen that is reactive with serum from a patient with discoid lupus erythematosus and chronic lymphocytic leukemia.
We determined the molecular weight, tissue distribution and subcellular distribution of the autoantigen and obtained limited amino acid sequence after purification by ion-exchange chromatography and trypsin digestion.
We identified the 74-kd autoantigen as synapsin I on the basis of the following observations. First, the autoantigen has properties consistent with synapsin I: molecular weight of approximately equals 74 kd, brain-specific distribution, presence in cytosol and on synaptosomes, and association with taxol-stabilized microtubules. Second, limited amino acid sequence determination after trypsin digestion of the autoantigen shows identity with synapsin I. Third, the autoimmune serum immunoblots fusion proteins that incorporate rat synapsin Ia. The autoantibodies reactive to synapsin Ia are of immunoglobulin (Ig) G and IgM class.
This is the first report of autoantibodies that are reactive to synapsin Ia. Autoantibodies that are reactive to synapsin Ia are not restricted to discoid lupus erythematosus patients, because we found identical reactivity in two of 18 sera from dsDNA-positive systemic lupus erythematosus patients and in two of 14 rheumatoid factor-positive sera. Whether autoantibodies to synapsin I are associated with neuropsychiatric manifestations is currently unknown.
我们报告了一种新的74kd脑特异性自身抗原的鉴定与特性，该抗原与盘状红斑狼疮和慢性淋巴细胞白血病患者的血清发生反应。
我们测定了该自身抗原的分子量、组织分布和亚细胞分布，并通过离子交换色谱法和胰蛋白酶消化纯化后获得了有限的氨基酸序列。
基于以下观察结果，我们将该74kd自身抗原鉴定为突触素I。首先，该自身抗原具有与突触素I一致的特性：分子量约为74kd，脑特异性分布，存在于细胞质和突触体中，并与紫杉醇稳定的微管相关。其次，对该自身抗原进行胰蛋白酶消化后测定的有限氨基酸序列显示与突触素I相同。第三，自身免疫血清对包含大鼠突触素Ia的融合蛋白进行免疫印迹。对突触素Ia有反应的自身抗体属于免疫球蛋白（Ig）G和IgM类。
这是关于对突触素Ia有反应的自身抗体的首次报道。对突触素Ia有反应的自身抗体并不局限于盘状红斑狼疮患者，因为我们在18例双链DNA阳性系统性红斑狼疮患者的血清中有2例以及14例类风湿因子阳性血清中有2例发现了相同的反应性。目前尚不清楚针对突触素I的自身抗体是否与神经精神表现相关。
