Bennett Jeffrey L, Lam Chiwah, Kalluri Sudhakar Reddy, Saikali Philippe, Bautista Katherine, Dupree Cecily, Glogowska Magdalena, Case David, Antel Jack P, Owens Gregory P, Gilden Don, Nessler Stefan, Stadelmann Christine, Hemmer Bernhard
Department of Neurology and Ophthalmology, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA.
Ann Neurol. 2009 Nov;66(5):617-29. doi: 10.1002/ana.21802.
The serum of most neuromyelitis optica (NMO) patients contains autoantibodies (NMO-IgGs) directed against the aquaporin-4 (AQP4) water channel located on astrocyte foot processes in the perivessel and subpial areas of the brain. Our objectives were to determine the source of central nervous system (CNS) NMO-IgGs and their role in disease pathogenesis.
Fluorescence-activated cell sorting and single-cell reverse transcriptase polymerase chain reaction were used to identify overrepresented plasma cell immunoglobulin (Ig) sequences in the cerebrospinal fluid (CSF) of an NMO patient after a first clinical attack. Monoclonal recombinant antibodies (rAbs) were generated from the paired heavy and light chain sequences and tested for target specificity and Fc effector function. The effect of CSF rAbs on CNS immunopathology was investigated by delivering single rAbs to rats with experimental autoimmune encephalomyelitis (EAE).
Repertoire analysis revealed a dynamic, clonally expanded plasma cell population with features of an antigen-targeted response. Using multiple independent assays, 6 of 11 rAbs generated from CSF plasma cell clones specifically bound to AQP4. AQP4-specific rAbs recognized conformational epitopes and mediated both AQP4-directed antibody-dependent cellular cytotoxicity and complement-mediated lysis. When administered to rats with EAE, an AQP4-specific NMO CSF rAb induced NMO immunopathology: perivascular astrocyte depletion, myelinolysis, and complement and Ig deposition.
Molecular characterization of the CSF plasma cell repertoire in an early NMO patient demonstrates that AQP4-specific Ig is synthesized intrathecally at disease onset and directly contributes to CNS pathology. AQP4 is now the first confirmed antigenic target in human demyelinating disease.
大多数视神经脊髓炎（NMO）患者的血清中含有针对位于脑内血管周围和软脑膜下区域星形胶质细胞足突上的水通道蛋白4（AQP4）水通道的自身抗体（NMO-IgGs）。我们的目的是确定中枢神经系统（CNS）中NMO-IgGs的来源及其在疾病发病机制中的作用。
采用荧光激活细胞分选和单细胞逆转录酶聚合酶链反应，对1例NMO患者首次临床发作后的脑脊液（CSF）中过度表达的浆细胞免疫球蛋白（Ig）序列进行鉴定。从配对的重链和轻链序列中产生单克隆重组抗体（rAbs），并检测其靶标特异性和Fc效应功能。通过将单个rAbs注射到实验性自身免疫性脑脊髓炎（EAE）大鼠中，研究CSF rAbs对CNS免疫病理学的影响。
谱系分析显示了一个动态的、克隆性扩增的浆细胞群体，具有抗原靶向反应的特征。使用多种独立检测方法，从CSF浆细胞克隆中产生的11种rAbs中有6种特异性结合AQP4。AQP4特异性rAbs识别构象表位，并介导针对AQP4的抗体依赖性细胞毒性和补体介导的细胞溶解。当将一种AQP4特异性NMO CSF rAb注射到EAE大鼠中时，可诱导NMO免疫病理学改变：血管周围星形胶质细胞缺失、髓鞘溶解以及补体和Ig沉积现象。
对1例早期NMO患者CSF浆细胞谱系的分子特征分析表明，AQP4特异性Ig在疾病发作时于鞘内合成，并直接导致CNS病理改变。AQP4现已成为人类脱髓鞘疾病中首个得到确认的抗原靶点。
