Cravens Petra D, Hussain Rehana Z, Miller-Little William A, Ben Li-Hong, Segal Benjamin M, Herndon Emily, Stüve Olaf
Department of Neurology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, United States of America.
Department of Neurology, University of Michigan, Ann Arbor, MI, United States of America.
PLoS One. 2016 Oct 25;11(10):e0165248. doi: 10.1371/journal.pone.0165248. eCollection 2016.
Interleukin (IL)-12 and IL-23 are heterodimers that share the p40 subunit, and both cytokines are critical in the differentiation of T helper (Th)1 and Th17 cells, respectively. Th1 and Th17 effector cells have been implicated in the pathogenesis of experimental autoimmune encephalitis (EAE), an animal model of the human central nervous system (CNS) autoimmune demyelinating disorder multiple sclerosis (MS). However, ustekinumab, a monoclonal antibody (mAb) against p40 failed to show efficacy over placebo in a phase II clinical trial in patients with MS. The role of p40 in initial T cell priming and maintenance in secondary lymphoid tissues is not yet well understood.
Active EAE was induced in the B6.129-IL12b strain of p40eYFP reporter mice (yet40 mice), and Th1 and Th17 polarized cells were adoptively transferred into p40-deficient mice. Cellular subsets were phenotyped by multi-parameter flow cytometry, and p40 tissue expression was identified by confocal microscopy.
We show that yet40 mice are susceptible to EAE, and that p40 is highly expressed in secondary lymphoid organs and the CNS during all stages of the disease. Interestingly, p40 expression in the recipient is not required for EAE induction after adoptive transfer of activated and differentiated encephalitogenic Th1 and Th17 cells into p40-deficient mice. Peripheral antagonism of T helper cell trophic factors critical for the differentiation and maintenance of Th1 and Th17 cells ameliorates EAE, indicating that p40 may play a critical role in the induction of CNS autoimmunity but not in its perpetuation.
Our data may explain why ustekinumab did not ameliorate paraclinical and clinical disease in patients with MS. In patients with already established disease, activated antigen-specific encephalitogenic CD4+ T cells are likely already differentiated, and are not dependent on p40 for maintenance. A clinical trial of longer duration with anti-p40 mAbs or other forms of pharmacological p40 antagonism, or sequential anti-p40 therapy following T cell depletion may show a benefit by affecting de novo generation of autoimmune T cells.
白细胞介素（IL）-12和IL-23是共享p40亚基的异二聚体，这两种细胞因子分别在辅助性T（Th）1细胞和Th17细胞的分化中起关键作用。Th1和Th17效应细胞与实验性自身免疫性脑脊髓炎（EAE）的发病机制有关，EAE是人类中枢神经系统（CNS）自身免疫性脱髓鞘疾病多发性硬化症（MS）的动物模型。然而，乌司奴单抗，一种抗p40单克隆抗体（mAb），在MS患者的II期临床试验中未显示出优于安慰剂的疗效。p40在初始T细胞致敏以及次级淋巴组织中T细胞维持方面的作用尚未完全明确。
在p40eYFP报告基因小鼠（yet40小鼠）的B6.129-IL12b品系中诱导活动性EAE，并将Th1和Th17极化细胞过继转移到p40缺陷小鼠体内。通过多参数流式细胞术对细胞亚群进行表型分析，并通过共聚焦显微镜鉴定p40组织表达。
我们发现yet40小鼠易患EAE，并且在疾病的所有阶段，p40在次级淋巴器官和CNS中均高表达。有趣的是，将活化并分化的致脑炎Th1和Th17细胞过继转移到p40缺陷小鼠后，EAE诱导并不需要受体中的p40表达。对Th1和Th17细胞分化及维持至关重要的辅助性T细胞营养因子的外周拮抗作用可改善EAE，这表明p40可能在CNS自身免疫的诱导中起关键作用，但在其持续过程中并非如此。
我们的数据可能解释了为什么乌司奴单抗不能改善MS患者的临床前和临床疾病。在已确诊疾病的患者中，活化的抗原特异性致脑炎CD4+ T细胞可能已经分化，并且维持不依赖于p40。使用抗p40 mAb或其他形式的p40药理学拮抗作用进行更长疗程的临床试验，或在T细胞耗竭后进行序贯抗p40治疗，可能会通过影响自身免疫性T细胞的重新产生而显示出益处。
