Mason Lesley J, Ravirajan Chelliah T, Rahman Anisur, Putterman Chaim, Isenberg David A
Department of Medicine, University College London, London, UK.
Arthritis Rheum. 2004 Mar;50(3):866-70. doi: 10.1002/art.20103.
Following recent reports that pathogenic murine anti-DNA antibodies bind to alpha-actinin, it was obviously of interest to assess the ability of human pathogenic anti-double-stranded DNA (anti-dsDNA) antibodies to bind this antigen. Both human monoclonal anti-DNA antibodies and antibodies affinity purified from the sera of patients with systemic lupus erythematosus (SLE) were investigated.
An enzyme-linked immunosorbent assay was established to measure immunoglobulin binding to alpha-actinin. Antibodies binding dsDNA were purified from the sera of SLE patients who either had active renal disease or had never had renal disease. Serum samples were selected at times when the patients' sera exhibited high IgG binding to dsDNA. The binding of supernatants from 3 high-affinity human anti-dsDNA IgG hybridomas (RH14, B3, and DIL-6) and 7 human IgM anti-DNA hybridomas was also investigated.
A greater proportion of anti-dsDNA IgG-binding antibodies purified from patients with renal disease bound to alpha-actinin than did those purified from the sera of patients without renal disease. The specificity of binding to the 100-kd alpha-actinin molecule was confirmed by Western blotting. The pathogenic human antibodies RH14 and B3 bound strongly to alpha-actinin, while nonpathogenic DIL-6 bound very weakly. RT84, the IgM antibody that binds dsDNA with the highest affinity, exhibited the greatest binding to alpha-actinin.
The results of our study support the findings of previous studies using murine anti-DNA monoclonal antibodies, which suggest that pathogenic anti-dsDNA antibodies cross-react with alpha-actinin.
近期有报道称致病性鼠抗DNA抗体可与α-辅肌动蛋白结合，因此评估人类致病性抗双链DNA（抗dsDNA）抗体结合该抗原的能力显然很有意义。我们对人单克隆抗DNA抗体以及从系统性红斑狼疮（SLE）患者血清中亲和纯化得到的抗体进行了研究。
建立酶联免疫吸附测定法以检测免疫球蛋白与α-辅肌动蛋白的结合。从患有活动性肾脏疾病或从未患过肾脏疾病的SLE患者血清中纯化结合dsDNA的抗体。在患者血清显示出高IgG结合dsDNA时选取血清样本。还研究了3株高亲和力人抗dsDNA IgG杂交瘤（RH14、B3和DIL-6）以及7株人IgM抗DNA杂交瘤的上清液的结合情况。
与从无肾脏疾病患者血清中纯化的抗体相比，从肾脏疾病患者中纯化的抗dsDNA IgG结合抗体与α-辅肌动蛋白结合的比例更高。通过蛋白质印迹法证实了与100-kdα-辅肌动蛋白分子结合的特异性。致病性人抗体RH14和B3与α-辅肌动蛋白强烈结合，而非致病性的DIL-6结合非常弱。与dsDNA结合亲和力最高的IgM抗体RT84与α-辅肌动蛋白的结合能力最强。
我们的研究结果支持了先前使用鼠抗DNA单克隆抗体的研究结果，表明致病性抗dsDNA抗体与α-辅肌动蛋白发生交叉反应。
