Mracsko Eva, Liesz Arthur, Stojanovic Ana, Lou Wilson Pak-Kin, Osswald Matthias, Zhou Wei, Karcher Simone, Winkler Frank, Martin-Villalba Ana, Cerwenka Adelheid, Veltkamp Roland
Department of Neurology, University of Heidelberg, D-69120 Heidelberg, Germany.
Department of Neurology, University of Heidelberg, D-69120 Heidelberg, Germany, Institute for Stroke and Dementia Research, Munich University Hospital, D-81377 Munich, Germany, Munich Cluster for Systems Neurology (SyNergy), D-80336 Munich, Germany, Groups.
J Neurosci. 2014 Dec 10;34(50):16784-95. doi: 10.1523/JNEUROSCI.1867-14.2014.
Neuroinflammation plays a key role in secondary brain damage after stroke. Although deleterious effects of proinflammatory cytokines are well characterized, direct cytotoxic effects of invading immune cells on the ischemic brain and the importance of their antigen-dependent activation are essentially unknown. Here we examined the effects of adaptive and innate immune cells-cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells-that share the direct perforin-mediated cytotoxic pathway on outcome after cerebral ischemia in mice. Although CTLs and NK cells both invaded the ischemic brain, only brain-infiltrating CTLs but not NK cells were more activated than their splenic counterparts. Depletion of CTLs decreased infarct volumes and behavioral deficit in two ischemia models, whereas NK cell depletion had no effect. Correspondingly, adoptive CTL transfer from wild-type into Rag1 knock-out mice increased infarct size. Adoptive CTL transfer from perforin knock-out or interferon-γ knock-out mice into Rag1 knock-out mice revealed that CTL neurotoxicity was mediated by perforin. Accordingly, CTLs isolated from wild-type or interferon-γ knock-out but not from perforin knock-out mice induced neuronal cell death in vitro. CTLs derived from ovalbumin-specific T-cell receptor transgenic mice were not activated and infiltrated less into the ischemic brain compared with wild-type CTLs. Their transfer did not increase the infarct size of Rag1 knock-out mice, indicating antigen-dependent activation as an essential component of CTL neurotoxicity. Our findings underscore the importance of antigen-dependent, direct cytotoxic immune responses in stroke and suggest modulation of CTLs and their effector pathways as a potential new strategy for stroke therapy.
神经炎症在中风后的继发性脑损伤中起关键作用。尽管促炎细胞因子的有害作用已得到充分表征，但侵入性免疫细胞对缺血性脑的直接细胞毒性作用及其抗原依赖性激活的重要性基本上尚不清楚。在此，我们研究了具有直接穿孔素介导的细胞毒性途径的适应性免疫细胞和先天性免疫细胞——细胞毒性T淋巴细胞（CTL）和自然杀伤（NK）细胞——对小鼠脑缺血后结局的影响。尽管CTL和NK细胞均侵入缺血性脑，但只有脑浸润性CTL而非NK细胞比其脾脏对应细胞更具活性。在两种缺血模型中，清除CTL可减少梗死体积和行为缺陷，而清除NK细胞则无影响。相应地，将野生型的CTL过继转移到Rag1基因敲除小鼠中会增加梗死面积。将穿孔素基因敲除或干扰素-γ基因敲除小鼠的CTL过继转移到Rag1基因敲除小鼠中显示，CTL的神经毒性是由穿孔素介导的。因此，从野生型或干扰素-γ基因敲除小鼠而非穿孔素基因敲除小鼠中分离出的CTL在体外可诱导神经元细胞死亡。与野生型CTL相比，从卵清蛋白特异性T细胞受体转基因小鼠衍生的CTL未被激活，并且向缺血性脑的浸润较少。它们的转移并未增加Rag1基因敲除小鼠的梗死面积，表明抗原依赖性激活是CTL神经毒性的重要组成部分。我们的研究结果强调了抗原依赖性直接细胞毒性免疫反应在中风中的重要性，并表明调节CTL及其效应途径是中风治疗的一种潜在新策略。
