小鼠单纯疱疹病毒Ⅰ型脑内潜伏感染LAT基因的表达及意义

目的　观察小鼠单纯疱疹病毒 I型 (HSV - 1)脑内潜伏感染时潜伏相关转录子 (L AT)在脑组织与三叉神经节 (TG)表达的差异 ,探讨 HSV - 1脑内潜伏再激活感染的发病机制。方法　用颅内病毒接种法给 Balb/ c小鼠接种单纯疱疹病毒 I型 F株 ,建立 HSV- 1脑内潜伏感染模型 ,病毒接种 8周后半定量 RT- PCR方法分别检测小鼠三叉神经节和脑的颞叶、小脑、脑干 L AT m RNA的表达。结果　小鼠三叉神经节和脑的不同部位均有 L AT m RNA的表达 ,三叉神经节、颞叶、小脑和脑干的半定量值分别为 :0 .6 86 0、0 .4 2 2 3、0 .3915和 0 .4 4 72。三叉神经节的半定量值高于脑的其它部位 (P<0 .0 5 )。结论　三叉神经节与脑组织 L AT m RNA表达水平的差异可能是两者病毒潜伏再激活感染发生机制不同的原因之一。     

IL-6在小鼠单纯疱疹病毒Ⅰ型潜伏与再激活感染中的表达及意义

目的探讨细胞因子IL-6在小鼠三叉神经节单纯疱疹病毒I型(HSV-1)潜伏与再激活感染时的表达及其意义。方法用角膜划痕法建立Balb/c小鼠HSV-1潜伏感染模型,紫外线角膜照射诱发疱疹病毒的再激活。免疫组织化学法检测小鼠三叉神经节病毒抗原和IL-6的表达,Mias2000图像分析系统测定其平均光密度值。结果HSV-1潜伏感染组小鼠三叉神经节细胞周围卫星细胞出现IL-6的弱表达,其OD值高于对照组(0.198±0.025 vs 0.145±0.017,P<0.05);再激活感染组小鼠三叉神经节IL-6的表达在2d达高峰,其OD值高于同一时间点单纯紫外线照射组(0.282±0.047 vs 0.230±0.040,P<0.05),同时三叉神经节单纯疱疹病毒抗原的表达在2~4d也达最高值。结论IL-6是一多功能的细胞因子,对于HSV-1潜伏感染的维持以及病毒再激活的发生和病毒的清除都起重要作用。     

血清IL-6在小鼠单纯疱疹病毒Ⅰ型复发感染中的意义

目的探讨血清中IL-6在小鼠单纯疱疹病毒Ⅰ型复发感染中的意义。方法将单纯疱疹病毒Ⅰ型潜伏感染的小鼠用过热作为应激原，诱发病毒的复发感染。以免疫组化检测病毒抗原的表达观察病毒活化；用放射免疫的方法检测血清中IL-6水平的变化。结果热应激后，疱疹病毒潜伏感染小鼠的部分三叉神经节细胞出现HSV-1抗原阳性表达，12-24h OD值达高峰，之后下降。小鼠血清IL-6水平也出现升高，12h为峰值，24h后开始下降，持续48h。与对照组比较差异有统计学意义（P〈0．05）。结论IL-6能够诱发单纯疱疹病毒-Ⅰ型的复发感染。     

血清IL-6在小鼠单纯疱疹病毒I型复发感染中的意义

目的探讨血清中IL-6在小鼠单纯疱疹病毒I型复发感染中的意义。方法将单纯疱疹病毒I型潜伏感染的小鼠用过热作为应激原,诱发病毒的复发感染。以免疫组化检测病毒抗原的表达观察病毒活化;用放射免疫的方法检测血清中IL-6水平的变化。结果热应激后,疱疹病毒潜伏感染小鼠的部分三叉神经节细胞出现HSV-1抗原阳性表达,12～24hOD值达高峰,之后下降。小鼠血清IL-6水平也出现升高,12h为峰值,24h后开始下降,持续48h。与对照组比较差异有统计学意义(P<0.05)。结论IL-6能够诱发单纯疱疹病毒-Ⅰ型的复发感染。     

三叉神经根区周围蛛网膜粘连与HSV-1感染关系的实验研究

目的 研究三叉神经痛患者三叉神经根区周围蛛网膜粘连与单纯疱疹病毒Ⅰ型感染的关系.方法 实验组40 例三叉神经痛患者三叉神经根区粘连的蛛网膜,对照组20 例外伤患者蛛网膜,每例蛛网膜分别做病理切片,PCR 检测HSV-1 特异性基因片段以及用HSV-1 单克隆抗体检测抗原的表达.结果 实验组病理切片光镜下粘连的蛛网膜主要以炎细胞浸润、水肿、钙化以及粘液样变性为主,检测到HSV-1 特异性基因片段阳性率为72.5% (29 /40),抗原阳性率为17.5% (7 /40),即以潜伏感染为主,少部分呈增值性感染.对照组病理切片有3 例细胞轻度水肿,余均为正常蛛网膜结构.有4 例HSV-1 特异性基因片段阳性,无抗原阳表达.卡方检验实验组和对照组蛛网膜HSV-1 的感染率有统计学差异(P＜0.05).结论 三叉神经根区蛛网膜的粘连与HSV-1 的感染密切相关;粘连的蛛网膜加剧了根区动脉对三叉神经根的压迫,是加重三叉神经痛的病因之一.     

三叉神经根区粘连蛛网膜组织中IL-6的表达及意义

目的探讨原发性三叉神经痛(TN)患者三叉神经根区粘连的蛛网膜组织中白细胞介素-6(IL-6)表达对单纯疱疹病毒Ⅰ型(HSV-1)的影响,并进一步探讨HSV-1感染与TN的关系。方法首先采用PCR方法检测TN患者三叉神经根区粘连的蛛网膜、无粘连的蛛网膜组织中HSV-1特异性基因片段,再用免疫印迹法分别检测上述组织中抗原的表达,从而确定病毒感染状态,将其重新划分为HSV-1潜伏感染组、增殖感染组、未感染组,再用酶联免疫吸附测定法分别定量检测三组蛛网膜标本组织和患者血清中IL-6水平。结果 HSV-1增殖感染组的蛛网膜组织中IL-6水平[(324.64±14.28)pg/g]高于潜伏感染组[(232.75±19.17)pg/g],潜伏感染组也高于未感染组[(93.54±14.08)pg/g],且均有统计学差异(P<0.01);血清中IL-6水平三组之间无明显差异(P>0.05)。结论 IL-6是HSV-1增殖感染过程中的重要介质。HSV-1的增殖感染可能诱发或加重三叉神经根区蛛网膜的粘连,蛛网膜组织可能也是HSV-1的潜伏基地。HSV-1感染可能是继血管压迫之外造成三叉神经根区蛛网膜粘连继而引发TN的另一重要因素。     

边缘系统和单纯疱疹性脑炎的定位

单纯疱疹Ⅰ型病毒可能多年隐居于宿主的三叉神经节中,但病毒之所以从隐居状态转变成侵犯破坏中枢神经组织以及为什么病毒只选择性破坏边缘系统的原因还不清楚。有关后者最初提出的解释是病毒经鼻腔内接种,沿嗅神经通路播散,进入邻近的颞叶和额叶皮层从而造成单纯疱疹脑炎(HSE)独特的定位。最近Davis等认为病毒来自三叉神经节的隐居部位,通过三叉神经小脑幕支向硬脑膜蔓延、     

γ-氨基丁酸在小鼠单纯疱疹病毒性脑炎中的表达变化

目的:观察γ-氨基丁酸(GABA)在小鼠单纯疱疹病毒性脑炎(HSE)病程中的表达变化,探讨其在病毒感染性脑损伤中的作用。方法:颅内病毒直接接种的方法建立小鼠疱疹病毒性脑炎模型,免疫组化的方法同时检测疱疹病毒(HSV)抗原和GABA在脑炎不同时间的表达变化,结果用图像分析系统进行分析。结果:病毒接种3d后脑组织颞叶、额叶、海马均出现HSV抗原阳性细胞,7-10dHSV抗原阳性细胞数目达高峰,阳性面积比最大,部分脑组织出现坏死,14d后抗原阳性表达细胞开始减少。GABA的表达变化与HSV的表达呈相反趋势,其阳性神经元数目则随病程而减少,在病程的7-10d表达降至最低,部分标本脑组织的坏死区几乎无表达,14d后表达开始增强。结论:GABA的表达变化与病毒性脑炎的严重程度有一定的相关性,可能对感染性脑损伤具有保护作用。     

MMP-9在单纯疱疹病毒性脑炎中的表达及对血脑屏障的影响

目的研究单纯疱疹病毒感染小鼠脑组织后MMP-9的变化及对血脑屏障通透性的影响。方法小鼠颅内注射单纯疱疹病毒1型(HSV-1)制造单纯疱疹病毒性脑炎模型,于感染后第3天、第7天,应用明胶酶谱分析检测脑组织中MMP-9活性,免疫荧光共聚焦检测MMP-9的细胞来源,通过检测渗出到脑血管外的伊文斯蓝(Evans Blue,EB)的含量以及脑组织水含量观察血脑屏障的通透性。结果 HSV-1感染后第3天、第7天病毒组中MMP-9活性较正常对照组明显增高,MMP-9活性增高与血脑屏障通透性增高相一致,给予MMP-9抑制剂BB-94后血脑屏障通透性降低,激活的小胶质细胞是MMP-9的主要来源。结论激活的小胶质细胞表达MMP-9破坏血脑屏障,在单纯疱疹病毒性脑炎的发病机制中起着重要作用。     

Stress-induced changes in pathophysiology and interferon gene expression during primary HSV-1 infection

Herpes simplex viruses (HSV) are the cause of the most common clinically recognized herpesvirus infections. The severity and duration of the primary HSV infection have been correlated with the frequency and severity of subsequent recurrences. Reactivation of latent HSV-1 can occur as a result of physical or emotional stress; however, the effects of stress on the modulation of the clinical pathophysiology of primary HSV-1 infections are not well understood. Although it is known that stress can be immunosuppresive, the immunological mechanisms by which stress modulates early immune responses, such as type I interferon gene expression during a primary HSV-1 infection are still not understood. It was hypothesized that due to suppressed early immune responses, stress would increase the severity of a cutaneous primary HSV-1 infection. In this investigation, a cutaneous HSV-1 model in the SKH-1 mouse was characterized and utilized to study the effect of restraint stress on the modulation of the clinical pathophysiology of primary HSV-1. Despite prolonged viral replication at the site of primary infection, restraint stress decreased the clinical severity of primary HSV-1 in the skin of SKH-1 mice. A decrease in type I and type II IFN expression was found in the skin of acutely infected restrained mice when compared to controls at day 3 post-infection using competitive RT-PCR. Using the glucocorticoid-receptor antagonist RU486, IFN-beta and INF-gamma expression were restored in restrained animals to control levels. Treatment with RU486 also increased the clinical severity of the cutaneous infection to control levels in restrained mice. Thus, RST masked the severity of an HSV-1 infection by decreasing its clinical signs while impairing the ability of the host to control viral replication prolonging the infectious period.     

Herpes simplex virus,type 1 invasion of the rabbit and mouse nervous systems revealed by in situ hybridization

Summary Using a³H-labelled virion DNA probe applied to tissue sections, we have previously identified the precise microscopic anatomical localtion of herpes simplex virus (HSV) during the acute and latent stages of infection of the mouse trigeminal ganglia and central nervous system (CNS). In the present investigation, we compared the mouse and the rabbit with respect to their ability to support acute and latent infections of trigeminal ganglionic and central nervous system neurons. We found that HSV-1, strain F, produced acute and latent infection of trigeminal ganglion cells in both mice and rabbits; however, lower levels of HSV-1 RNA were expressed in rabbit neurons as compared to mouse neurons, and many fewer neurons of the rabbit supported an acute infection than in the mouse. Studies of the trigeminal system within the CNS revealed that HSV-1 established latency more readily in the mouse than in the rabbit. The histopathology observed in acutely infected rabbit brain was less intense and less widespread than in mouse brain.Supported by the Medical Research Service of the Veterans Administration and by Institutional and Biomedical Research Support Funds awarded by the Dean of the Medical School, University of Utah     

The dual role of CD8+ T lymphocytes in the development of stress-induced herpes simplex encephalitis

Despite the generally restrictive nature of the blood–brain barrier (BBB), circulating lymphocytes can infiltrate into the central nervous system (CNS) during a variety of disease states. Although the contributions of these lymphocytes to CNS-associated disease have been identified in some viral models, the factors which govern this infiltration following herpes simplex virus (HSV) infection remain to be elucidated. We have developed a murine model of HSV encephalitis (HSE) to define the relationship among psychological stress, the recruitment of HSV-specific T cells into the CNS, and the development of HSE. Naive mice, as well as mice that had been vaccinated with a recombinant vaccinia virus (rVVESgB498–505) that elicits the generation of HSV-1 gB498–505-specific CD8⁺ T cells, were infected intranasally (i.n.) with HSV-1 McIntyre. Beginning one day prior to HSV-1 infection and continuing for a total of 9 days, naive and vaccinated mice were exposed to a well-established stressor, restraint stress. Naive, stressed mice exhibited increased symptoms of HSE and HSE-associated mortality as compared to non-stressed controls. A concomitant increase in CD4⁺ and CD8⁺ T cells in the brain was observed throughout the infection, with CD8⁺ T cells outnumbering CD4⁺ T cells. The development of HSE in these naive, stressed mice was accompanied by a delayed infiltration of gB498–505-specific CD8⁺ T cells after HSV spread into the brain. In contrast, both stressed and non-stressed rVVESgB498–505-vaccinated mice possessed gB498–505-specific CD8⁺ T cells prior to HSV challenge and were protected against HSE despite having detectable HSV-1 DNA in the brain. Together, these findings suggest that a delayed infiltration of CD8⁺ T cells into the brain may promote HSE in naive mice, while the presence of HSV-specific CD8⁺ T cells in the brain prior to HSV challenge is protective, possibly by limiting HSV replication and spread within the CNS.     

Innate defense mechanisms against HSV-1 infection in the target tissues,skin and brain

Herpes simplex virus type 1 (HSV-1) initiates productive infection in mucocutaneous tissues to cause cold sores and establishes latent infection in the trigeminal ganglia. Under certain circumstances, HSV-1 may cause encephalitis. Here, we compared host innate defenses against HSV-1 in the two clinically relevant tissues, skin and brain, using a unique ex vivo system of organ culture. Upon HSV-1 infection and spread, apoptosis induction was observed in the skin, but not in brain tissues. While the two tissues elicited interferon (IFN-β) response upon HSV1 infection, IFN induction was more robust in the skin compared to the brain. Moreover, antiviral response to exogenous IFNβ treatment was much stronger in the skin compared to brain tissues. This observation was not related to the availability of the IFN receptor on cells’ surface. Taken together, our study demonstrates differential innate antiviral responses to HSV-1 infection that may be exploited in future development of selective and tissue-specific anti-viral treatments.     

Stress-induced reactivation of latent herpes simplex virus infection in rat lumbar dorsal root ganglia

Clinical reports suggest that stress precipitates recurrent cutaneous Herpes simplex virus (HSV) infection, presumably by reactivating latent infection in sensory ganglia with subsequent centrifugal axonal spread to the skin. As an initial test of this hypothesis, rats with latent HSV, type-1, (HSV-1) infection in lumbar dorsal root ganglia (DRG) were exposed to a well-characterized acute stressor that produced gastric ulcers (U) and elevated plasma corticosterone (CS) concentrations. Stress-induced reactivation of latent HSV infection was suggested by the earlier appearance of cytopathic effect (CPE) in human foreskin fibroblast monolayers co-cultivated with ganglia from stressed rats than from nonstressed ones (4.5 ± 0.2 and 6.4 ± 0.4 [mean ± SEM] days respectively; p<0.001). No CPE was detected in monolayers co-cultivated with ganglia from non-infected rats. These initial results suggest that acute stress reactivates latent HSV-1 ganglionic infection.     

PCR-mediated search for herpes simplex virus DNA in sections of brain from patients with multiple sclerosis and other neurological disorders.

Herpes simplex virus (HSV) has been shown to cause central nervous system demyelination in experimental animals and several studies have implicated HSV in the aetiology of multiple sclerosis (MS). We have used the polymerase chain reaction to look for DNA of both type 1 HSV (HSV-1) and type 2 HSV (HSV-2) in formalin-fixed paraffin-embedded brain tissues from patients with MS and other neurological diseases. Primers which amplify a fragment of the normal cellular gene c-myc were included in the reactions to assess the preservation of DNA in the tissue samples. 77 plaques of demyelination from 23 patients with MS were examined. HSV-1 DNA was amplified from only one plaque. This plaque involved the trigeminal root entry zone in the pons and it is suggested that the presence of viral DNA was related to the site examined rather than to the demyelination per se. HSV-2 DNA was amplified from none of the plaques. As expected, HSV-1 DNA was detected in the brains of 6 patients who died of HSV-1 encephalitis and HSV-2 DNA was amplified from the brain of a neonate with congenital HSV-2 infection. In sections of brain from 39 patients with a wide range of other neurological diseases HSV-1 DNA was detected in the pons of only 1 patient, who had AIDS associated with cytomegalovirus ventriculitis; subsequent investigation confirmed the presence of concomitant HSV-1 brain stem infection.(ABSTRACT TRUNCATED AT 250 WORDS)