Department of Medical Microbiology & Immunology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates.
Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates.
Front Immunol. 2021 Nov 25;12:764937. doi: 10.3389/fimmu.2021.764937. eCollection 2021.
Epstein-Barr virus (EBV) is a common herpesvirus associated with malignant and non-malignant conditions. An accumulating body of evidence supports a role for EBV in the pathogenesis of multiple sclerosis (MS), a demyelinating disease of the CNS. However, little is known about the details of the link between EBV and MS. One obstacle which has hindered research in this area has been the lack of a suitable animal model recapitulating natural infection in humans. We have recently shown that healthy rabbits are susceptible to EBV infection, and viral persistence in these animals mimics latent infection in humans. We used the rabbit model to investigate if peripheral EBV infection can lead to infection of the CNS and its potential consequences. We injected EBV intravenously in one group of animals, and phosphate-buffered saline (PBS) in another, with and without immunosuppression. Histopathological changes and viral dynamics were examined in peripheral blood, spleen, brain, and spinal cord, using a range of molecular and histopathology techniques. Our investigations uncovered important findings that could not be previously addressed. We showed that primary peripheral EBV infection can lead to the virus traversing the CNS. Cell associated, but not free virus in the plasma, correlated with CNS infection. The infected cells within the brain were found to be B-lymphocytes. Most notably, animals injected with EBV, but not PBS, developed inflammatory cellular aggregates in the CNS. The incidence of these aggregates increased in the immunosuppressed animals. The cellular aggregates contained compact clusters of macrophages surrounded by reactive astrocytes and dispersed B and T lymphocytes, but not myelinated nerve fibers. Moreover, studying EBV infection over a span of 28 days, revealed that the peak point for viral load in the periphery and CNS coincides with increased occurrence of cellular aggregates in the brain. Finally, peripheral EBV infection triggered temporal changes in the expression of latent viral transcripts and cytokines in the brain. The present study provides the first direct evidence for the role of peripheral EBV infection in CNS pathology, and highlights a unique model to dissect viral mechanisms contributing to the development of MS.
EB 病毒(EBV)是一种常见的疱疹病毒,与恶性和非恶性疾病有关。越来越多的证据支持 EBV 在多发性硬化症(MS)的发病机制中起作用,MS 是一种中枢神经系统的脱髓鞘疾病。然而,关于 EBV 与 MS 之间的联系的细节知之甚少。阻碍该领域研究的一个障碍是缺乏能够重现人类自然感染的合适动物模型。我们最近表明,健康的兔子易受 EBV 感染,并且这些动物中的病毒持续感染类似于人类的潜伏感染。我们使用兔模型来研究外周 EBV 感染是否会导致中枢神经系统感染及其潜在后果。我们在一组动物中静脉注射 EBV,在另一组动物中注射磷酸盐缓冲盐水(PBS),同时进行和不进行免疫抑制。使用一系列分子和组织病理学技术,在外周血、脾脏、大脑和脊髓中检查组织病理学变化和病毒动力学。我们的研究揭示了以前无法解决的重要发现。我们表明,原发性外周 EBV 感染可导致病毒穿过中枢神经系统。与 CNS 感染相关的是血浆中的细胞相关而不是游离病毒。在大脑中发现的感染细胞是 B 淋巴细胞。最值得注意的是,注射 EBV 而不是 PBS 的动物在中枢神经系统中出现炎症性细胞聚集。免疫抑制动物中这些聚集物的发生率增加。这些聚集物包含被反应性星形胶质细胞包围的巨噬细胞紧密簇,以及分散的 B 和 T 淋巴细胞,但没有髓鞘化的神经纤维。此外,研究 EBV 感染 28 天,发现外周和中枢神经系统中病毒载量的峰值与大脑中细胞聚集物的增加同时发生。最后,外周 EBV 感染引发了大脑中潜伏病毒转录物和细胞因子表达的时间变化。本研究首次直接证明外周 EBV 感染在中枢神经系统病理学中的作用,并突出了一种独特的模型,用于剖析导致 MS 发展的病毒机制。