CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, Centre Broca Nouvelle-Aquitaine, 146 rue Léo Saignat, CS 61292 Case 130, 33076 Bordeaux Cedex, France; Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, Centre Broca Nouvelle-Aquitaine, 146 rue Léo Saignat, CS 61292 Case 130, 33076 Bordeaux Cedex, France.
CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, Centre Broca Nouvelle-Aquitaine, 146 rue Léo Saignat, CS 61292 Case 130, 33076 Bordeaux Cedex, France; Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, Centre Broca Nouvelle-Aquitaine, 146 rue Léo Saignat, CS 61292 Case 130, 33076 Bordeaux Cedex, France.
J Neurosci Methods. 2018 Jul 1;304:76-82. doi: 10.1016/j.jneumeth.2018.04.012. Epub 2018 Apr 21.
Over the past decade, an increasing number of neurological and neuropsychiatric diseases have been associated with the expression of autoantibodies directed against neuronal targets, including neurotransmitter receptors. Although cell-based assays are routinely used in clinics to detect the presence of immunoglobulins, such tests often provide heterogeneous outcomes due to their limited sensitivity, especially at low titers. Thus, there is an urging need for new methods allowing the detection of autoantibodies in seropositive patients that cannot always be clinically distinguished from seronegative ones.
Here we make a case for single nanoparticle imaging approaches as a highly sensitive antibody detection assay. Through high-affinity interactions between functionalized nanoparticles and autoantibodies that recognize extracellular domains of membrane neuronal targets, single nanoparticle imaging allows a live surface staining of transmembrane proteins and gives access to their surface dynamics.
RESULTS AND COMPARISON WITH EXISTING METHOD(S): We show here that this method is well-suited to detect low titers of purified immunoglobulin G (IgG) from first-episode psychotic patients and demonstrate that these IgG target glutamatergic N-Methyl-d-Aspartate receptors (NMDAR) in live hippocampal neurons. The molecular behaviors of targeted membrane receptors were indistinguishable from those of endogenous GluN1 NMDAR subunit and were virtually independent of the IgG concentration present in the sample contrary to classical cell-based assays.
Single nanoparticle imaging emerges as a real-time sensitive method to detect IgG directed against neuronal surface proteins, which could be used as an additional step to rule out ambiguous seropositivity diagnoses.
在过去的十年中，越来越多的神经和神经精神疾病与针对神经元靶标的自身抗体的表达有关，包括神经递质受体。尽管细胞为基础的检测方法在临床上通常用于检测免疫球蛋白的存在，但由于其灵敏度有限，特别是在低滴度时，这些测试往往会产生不均匀的结果。因此，迫切需要新的方法来检测不能总是与血清阴性患者区分开来的血清阳性患者中的自身抗体。
在这里，我们提出了一种单纳米颗粒成像方法作为一种高度敏感的抗体检测方法。通过功能化纳米颗粒与识别膜神经元靶标细胞外结构域的自身抗体之间的高亲和力相互作用，单纳米颗粒成像允许对跨膜蛋白进行实时表面染色，并可访问其表面动力学。
我们在这里表明，该方法非常适合检测首发精神病患者中纯化免疫球蛋白 G（IgG）的低滴度，并证明这些 IgG 靶向谷氨酸 N-甲基-D-天冬氨酸受体（NMDAR）在活海马神经元中。靶向膜受体的分子行为与内源性 GluN1 NMDAR 亚基的行为无法区分，并且与传统的基于细胞的检测方法相反，实际上与样品中存在的 IgG 浓度无关。
单纳米颗粒成像作为一种实时敏感的方法来检测针对神经元表面蛋白的 IgG，可作为排除模棱两可的血清阳性诊断的附加步骤。
