Toxoplasma gondii’s tropism for and persistence in the central nervous system (CNS) underlies the symptomatic disease that T. gondii causes in humans. Our recent work has shown that neurons are the primary CNS cell with which Toxoplasma interacts and which it infects in vivo. This predilection for neurons suggests that T. gondii’s persistence in the CNS depends specifically upon parasite manipulation of the host neurons. Yet, most work on T. gondii-host cell interactions has been done in vitro and in nonneuronal cells. We address this gap by utilizing our T. gondii-Cre system that allows permanent marking and tracking of neurons injected with parasite effector proteins in vivo. Using laser capture microdissection (LCM) and RNA sequencing using RNA-seq, we isolated and transcriptionally profiled T. gondii-injected neurons (TINs), Bystander neurons (nearby non-T. gondii-injected neurons), and neurons from uninfected mice (controls). These profiles show that TIN transcriptomes significantly differ from the transcriptomes of Bystander and control neurons and that much of this difference is driven by increased levels of transcripts from immune cells, especially CD8⁺ T cells and monocytes. These data suggest that when we used LCM to isolate neurons from infected mice, we also picked up fragments of CD8⁺ T cells and monocytes clustering in extreme proximity around TINs and, to a lesser extent, Bystander neurons. In addition, we found that T. gondii transcripts were primarily found in the TIN transcriptome, not in the Bystander transcriptome. Collectively, these data suggest that, contrary to common perception, neurons that directly interact with or harbor parasites can be recognized by CD8⁺ T cells.

中文翻译：

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转录分析表明 T 细胞在注射了弓形虫蛋白的神经元周围聚集。

弓形虫对中枢神经系统 (CNS) 的趋向性和持久性是弓形虫在人类中引起的症状性疾病的基础。我们最近的工作表明，神经元是弓形虫与之相互作用并在体内感染的主要 CNS 细胞。这种对神经元的偏好表明弓形虫在中枢神经系统中的持久性特别依赖于寄生虫对宿主神经元的操纵。然而，大多数关于弓形虫-宿主细胞相互作用的工作都是在体外和非神经元细胞中完成的。我们通过利用我们的弓形虫来弥补这一差距-Cre 系统允许永久标记和跟踪体内注射寄生虫效应蛋白的神经元。使用激光捕获显微切割 (LCM) 和使用 RNA-seq 的 RNA 测序，我们分离并转录分析了注射弓形虫的神经元 (TIN)、旁观者神经元（附近的非弓形弓形虫注射神经元）和未感染小鼠的神经元（控制）。这些图谱表明，TIN 转录组与旁观者和对照神经元的转录组显着不同，而且这种差异在很大程度上是由免疫细胞（尤其是 CD8 ⁺T 细胞和单核细胞。这些数据表明，当我们使用 LCM 从受感染的小鼠中分离神经元时，我们还拾取了 CD8 ⁺ T 细胞和单核细胞的碎片，这些碎片聚集在 TIN 周围极其接近的地方，并且在较小程度上还拾取了旁观者神经元。此外，我们发现T. gondii转录本主要存在于 TIN 转录组中，而不是 Bystander 转录组中。总的来说，这些数据表明，与通常的看法相反，直接与寄生虫相互作用或携带寄生虫的神经元可以被 CD8 ⁺ T 细胞识别。