Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan.
J Biomed Sci. 2012 Jun 26;19(1):61. doi: 10.1186/1423-0127-19-61.
Rabies is known to be lethal in human. Treatment with passive immunity for the rabies is effective only when the patients have not shown the central nerve system (CNS) signs. The blood-brain barrier (BBB) is a complex functional barrier that may compromise the therapeutic development in neurological diseases. The goal of this study is to determine the change of BBB integrity and to assess the therapeutic possibility of enhancing BBB permeability combined with passive immunity in the late stage of rabies virus infection.
The integrity of BBB permeability in rats was measured by quantitative ELISA for total IgG and albumin levels in the cerebrospinal fluid (CSF) and by exogenously applying Evans blue as a tracer. Western blotting of occludin and ZO-1, two tight junction proteins, was used to assess the molecular change of BBB structure.The breakdown of BBB with hypertonic arabinose, recombinant tumor necrosis factor-alpha (rTNF-γ), and focused ultrasound (FUS) were used to compare the extent of BBB disruption with rabies virus infection. Specific humoral immunity was analyzed by immunofluorescent assay and rapid fluorescent focus inhibition test. Virus-neutralizing monoclonal antibody (mAb) 8-10E was administered to rats with hypertonic breakdown of BBB as a passive immunotherapy to prevent the death from rabies.
The BBB permeability was altered on day 7 post-infection. Increased BBB permeability induced by rabies virus infection was observed primarily in the cerebellum and spinal cord. Occludin was significantly decreased in both the cerebral cortex and cerebellum. The rabies virus-specific antibody was not strongly elicited even in the presence of clinical signs. Disruption of BBB had no direct association with the lethal outcome of rabies. Passive immunotherapy with virus-neutralizing mAb 8-10E with the hypertonic breakdown of BBB prolonged the survival of rabies virus-infected rats.
We demonstrated that the BBB permeability was altered in a rat model with rabies virus inoculation. Delivery of neutralizing mAb to the infected site in brain combined with effective breakdown of BBB could be an aggressive but feasible therapeutic mode in rabies when the CNS infection has been established.
狂犬病在人类中是致命的。只有在患者尚未出现中枢神经系统（CNS）症状时，被动免疫治疗狂犬病才有效。血脑屏障（BBB）是一种复杂的功能性屏障，可能会影响神经疾病的治疗开发。本研究的目的是确定 BBB 完整性的变化，并评估在狂犬病病毒感染后期增强 BBB 通透性并结合被动免疫的治疗可能性。
通过定量 ELISA 测量大鼠脑脊液（CSF）中总 IgG 和白蛋白水平来测量 BBB 通透性的完整性，并通过外源性应用 Evans 蓝作为示踪剂。Western blot 分析紧密连接蛋白 occludin 和 ZO-1 的变化，以评估 BBB 结构的分子变化。高渗阿拉伯糖、重组肿瘤坏死因子-α（rTNF-γ）和聚焦超声（FUS）破坏 BBB，以比较与狂犬病病毒感染相比 BBB 破坏的程度。通过免疫荧光检测和快速荧光焦点抑制试验分析特异性体液免疫。用高渗破坏 BBB 后给大鼠注射病毒中和单克隆抗体（mAb）8-10E 作为被动免疫治疗，以防止狂犬病死亡。
感染后第 7 天 BBB 通透性发生改变。狂犬病病毒感染引起的 BBB 通透性增加主要发生在小脑和脊髓。皮质和小脑的 occludin 明显减少。即使出现临床症状，也未能强烈引发狂犬病病毒特异性抗体。BBB 破坏与狂犬病的致命结局没有直接关系。用病毒中和 mAb 8-10E 结合高渗破坏 BBB 的被动免疫治疗延长了感染狂犬病病毒大鼠的存活时间。
我们证明了狂犬病病毒接种大鼠模型中 BBB 通透性发生改变。将中和抗体递送至感染部位的大脑并结合有效的 BBB 破坏可能是一种积极但可行的治疗模式，适用于 CNS 感染已经建立的狂犬病。
