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The ganglionic cell type in which varicella-zoster virus (VZV) is latent in humans was analyzed by using antibodies raised against in vitro-expressed VZV open reading frame 63 protein. VZV open reading frame 63 protein was detected exclusively in the cytoplasm of neurons of latently infected human trigeminal and thoracic ganglia. This is, to our knowledge, the first identification of a herpesvirus protein expressed during latency in the human nervous system.

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Herpes viruses have been used as retrograde transsynaptic tracers to identify pathways from the CNS to specific target tissues. We used herpes simplex virus to identify central nervous system neurons responsible for control of the kidney. Herpes simplex type 1 or herpes simplex type 2 was injected into rat kidneys and herpes simplex type 1 was microinjected into hamster and guinea pig kidneys. After three to seven days, ganglia, spinal cords and brains were examined using immunohistochemistry to visualize the virus-infected neurons. Our first experiments demonstrated that rats were not susceptible to infection with neurotropic strains of herpes simplex type 1. Injections of a wildtype strain of herpes simplex type 2 into rat kidneys led to nonspecific infection of many central nervous system neurons and glia. In contrast, herpes simplex type 1 injections in hamsters and guinea pigs caused specific infection of limited numbers of neurons in approximately one-third of the animals and the study was continued using hamsters. Sympathetic preganglionic neuron labelling was found in the ipsilateral intermediolateral cell column of the spinal cord as well as the lateral funiculus. Most infected preganglionic neurons were located in the seventh to the ninth thoracic spinal segments. Infected neurons were not found in the dorsal or ventral horn of the spinal gray matter and only one or two cells were found in the brainstem. Sympathetic preganglionic neuron morphology was usually normal, showing detailed dendritic arborizations, and lysis was infrequent. Small infected cells were sometimes observed close to sympathetic preganglionic neurons. Because herpes simplex type 1 virus was not detected immunocytochemically in ganglionic neurons in these same hamsters, the polymerase chain reaction was used in some additional hamsters to detect viral DNA in the T12 and T13 chain ganglia and splanchnic ganglia ipsilateral to the kidney injected with herpes simplex type 1. Finally, the overall distribution of renal postganglionic and splanchnic preganglionic neurons in hamsters was examined for comparison to the number and locations of virus-labelled neurons. Retrograde transport of the fluorescent dye FluoroGold demonstrated that (i) renal postganglionic neurons are distributed in the T10-L1 chain ganglia and in the prevertebral splanchnic ganglion and (ii) splanchnic preganglionic neurons are located in the T3-T12 spinal segments, predominantly in the intermediolateral and funicular spinal autonomic nuclei. In conclusion, herpes simplex type 1 virus infected an exclusive population of "renal" neurons in hamsters without lysis and with little cellular reaction to the infection after a survival period of three days, permitting these neurons to be studied in detail.

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Sensory and sympathetic ganglia from 12 cases of human immunodeficiency virus type 1 (HIV-1) infection, all but one without clinical evidence of peripheral nerve disease, were studied immunocytochemically for their content of lymphocytes, macrophages, MHC Class II antigens and HIV-1 and cytomegalovirus antigens. They were compared with ganglia from 7 normal and peripheral nerve disease control cases. Compared with normal controls, many of the ganglia from the majority of HIV-1-infected subjects contained more T lymphocytes and macrophages and enhanced MHC class II expression. A few also showed occasional neuronal degeneration which was not present in the normal controls. In 7 cases HIV-1 gp41 envelope protein and/or p24 core protein antigens were detected in intraganglionic macrophages. Sensory ganglia contained more gp41 HIV-1 antigen than sympathetic ganglia. There was no clear correlation between detection of HIV-1 antigens in ganglia and in the CNS. Detection of HIV-1 antigens in ganglia was more common in cases of HIV-1 infection that had progressed to clinical AIDS by the time of death (71%) than in those that had not done so (40%). It is concluded that there is commonly a mild ganglionitis which is asymptomatic in the absence of detailed clinical testing and frequently associated with local presence of HIV-1 antigens in sensory and sympathetic ganglia in AIDS.

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Normal human trigeminal and thoracic ganglia latently infected with varicella-zoster virus (VZV) were identified by polymerase chain reaction (PCR). Total RNA was extracted from these ganglia and treated with DNase until ganglionic RNA was free of VZV DNA as determined by PCR. Radiolabeled cDNA synthesized by priming with random oligonucleotides was hybridized to Southern blots containing recombinant clones that spanned greater than 95% of the VZV genome. The single region of the VZV genome detected was the 12.5-kb SalI C fragment located in the unique long segment of the viral genome. Two additional regions of the VZV genome, EcoRI G and SalI B, were detected in RNA from adult dorsal root ganglia and infant nervous system tissue.

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Herpes zoster ophthalmicus occurs worldwide, usually in healthy adults, but, increasingly in patients who are immunocompromised. After primary varicella infection (chickenpox), the virus lies dormant in the sensory ganglion until it becomes reactivated as zoster. Involvement of the ophthalmic branch of the trigeminal nerve is characterized early by corneal dysesthesia and dendritiform keratopathy, and these are self-limited. However, smoldering disease may cause pathological changes in the ocular structures through direct invasion of virus, secondary inflammation, and alterations of autoimmune mechanisms. Antiviral agents have demonstrated some success in resolving early signs and symptoms, but their role in preventing and treating late complications remains to be fully studied. Until a definitive antiviral agent is established, the benefits of steroid use in certain acute inflammatory processes outweight its risk of reducing host immunity. Corneal complications of herpes zoster ophthalmicus sometimes require surgical intervention.

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The primary replication of one strain of HSV was generally unaffected by the simultaneous inoculation of another strain either at the same site or at a different site within the same dermatome. Exceptions to this were the result of the generation of intertypic recombinants which were readily isolated only from sensory ganglia 5 and 6 days after inoculation with a mixture of HSV-1 and HSV-2 and from explant culture of the resultant latently infected ganglia. By restriction enzyme analysis the majority of the recombinant strains from primary infection were characterized as HSV 1; all those from latently infected ganglia were characterized as type 2.

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Vaccinia virus recombinants expressing glycoproteins B (vgB11), D (VgD52), E (gE/7.5 and gE/4B), G (gG-vac), H (gH-vac), and I (gI-vac) of HSV-1 were used to compare the protective response to these individual glycoproteins in the mouse. Glycoprotein D induced the best neutralizing antibody titers and the most increased rates of HSV clearance from the ear as well as good protection from the establishment of latent HSV infections in the sensory ganglia. Glycoprotein B also induced good neutralizing antibody titers and as great a protection from the establishment of latency as gD although the rate of virus clearance from the ear was not as great as after immunization with gD. Glycoprotein E induced weak neutralizing antibody but gG, gH, and gI did not show a neutralizing antibody response. At higher challenge doses of virus (10(6) PFU HSV-1 in the ear), gE induced a protective response by increasing the rate of virus clearance and reducing the acute infection of ganglia as compared to negative control immunized mice. However there was no protection from the establishment of latent infections after immunization with gE. No protective response was seen to gG, gH, or gl.

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Mouse L cell lines constitutively expressing glycoproteins B or D of herpes simplex virus type 1 (LTKgB and LTKgD respectively) were used to study the longevity of the immune response to these viral glycoproteins in mice. Two immunizations with the cell lines were necessary to induce a persisting antibody response (present for over 200 days). Only LTKgD induced a neutralizing at antibody response in mice and this also remained at high titres over 200 days after two inoculations. The presence in mice of precursor cytotoxic T lymphocytes specific for gB expressed in the L cells was also shown up to 270 days after immunization. Mice immunized with the cell lines showed an increased rate of virus clearance from the ear pinna, inoculation with LTKgD resulting in more clearance than LTKgB at 7 days post-immunization. This type of protection was reduced with time after inoculation, until by day 161 there was no significant difference in virus titres between immunized and control groups. However, LTKgD immunization protected against the establishment of latent infections in the ganglia of mice even up to 186 days post-inoculation.

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Herpes Simplex Type I (HSV I) causes some infections such as herpes labialis, encephalitis, keratoconjunctivitis and also some cranial nerve syndromes such as acute vestibular neuritis, migraine and Meniere's disease in human. We used 4 fixated and 16 fresh cadavers to isolate HSV I virus from the Superior Cervical Ganglia. The ganglia materials are inoculated to PRK (primary rabbit kidney), VERO (African Green Monkey Kidney) and BHK 21 (Baby Hamster Kidney) cell lines in order to isolate the virus. We isolated HSV I virus from 12 fresh cadavers' cervical ganglia (75%) and neutralisation test is performed in order to characterize HSV I. But we could not isolate the virus from any of the fixated cadavers.

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The polymerase chain reaction (PCR) was employed to detect herpes simplex virus (HSV) sequences in the DNA, and HSV gene expression in total cell RNA, extracted from cervical and trigeminal ganglia of mice during productive and latent infection with HSV-1, strain SC16. Such gene expression was detected in 1 microgram or less of RNA, the quantity anticipated to be present in one or two cervical ganglia. Within the limits of the primers available, gene expression during latency appeared to be restricted to the latency-associated transcript (LAT). The 195 base portion of the LAT amplified by the PCR was sequenced and found to contain several base changes and deletions with respect to published sequences for different HSV strains. These mutations, within the putative open reading frame 2 of the LAT, formed stop or terminator signals, which suggests that the LAT does not act to establish or maintain latency through translation to a protein. The primers for the LAT also amplified a 300 bp fragment from any murine and some other mammalian RNAs. Apart from the oligonucleotide primers, this fragment did not show any homology with HSV.

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Mice were inoculated with herpes simplex virus (HSV) type 1 in the skin of the neck. The extent of primary and latent infection in the second and third cervical ganglia was investigated. Immunoperoxidase staining of ganglia during primary infection demonstrated HSV antigens initially in a restricted area of the ganglion. By the 5th day after infection, antigen was more widespread. Such a change in the staining pattern is explicable in terms of the zosteriform spread of virus from neurons innervating the site of infection to others supplying other areas of the dermatome. A maximum of approximately 10% of neurons became infected. By the 7th day staining was limited to a few cells. During latent infection, enzymic disaggregation of ganglia followed by immunoperoxidase staining or infectious centre assay indicated that virus reactivation began within 30 h of removal of ganglia and occurred in approximately 1% of viable neurons.

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A genetically engineered herpes simplex virus type 1 (HSV-1)thymidine kinase (TK) deletion mutant has been constructed and used to investigate the role of this gene in pathogenesis. Inoculation of mice with the HSV TK deletion mutant resulted in the establishment of latent ganglionic infection as demonstrated by superinfection of explanted ganglia with wild-type (wt) virus but not by routine explant culture suggesting that the virus-encoded TK is not essential for the establishment of latent infection but may be necessary for either reactivation or virus replication following reactivation. In addition, Southern blot hybridization has been used to demonstrate in vivo complementation of this mutant by wt virus in both peripheral and central nervous system tissues of mice during acute infection and to show that such complementation can result in the establishment and reactivation of latent TK- infection.

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During primary infection with herpes simplex virus type 1, elimination of the antibody response by B cell suppression did not interfere with clearance of virus from skin. However, spread of virus within the peripheral nervous system was more extensive in B cell-suppressed animals compared with that in fully immunocompetent mice. Mice that had previously recovered from herpes simplex virus infection of the ear pinna, when subsequently reinfected in the flank, showed restricted viral replication in the skin and cleared virus more rapidly than did animals experiencing primary infection. B cell suppression did not compromise the ability of mice to resist reinfection compared with the ability of normal immune animals. The implications of the above findings with regard to future immunoprophylaxis and the interpretation of experiments designed to test for immunity are discussed.

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Effects of DNA hypomethylating agents on reactivation of herpes simplex virus from latently infected mouse ganglia in vitro were examined. L-ethionine and 5-azacytidine increased the incidence of reactivation. Dimethylsulphoxide and 5-azacytidine allowed earlier detection of virus.

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The effect of herpes simplex virus (HSV) injection on the sympathetic nerve system of newborn rats was studied at structural, ultrastructural, and immunohistochemical levels. It was found that HSV injected into the anterior eye chamber is retrogradely transported and reaches the nerve cell bodies of the ipsilateral superior cervical ganglion (SCG) after 18-24 hr, causing complete cell destruction within 3-4 days. In subsequent days, nerve cells of the contralateral SCG, spinal sensory ganglia, chromaffin cells and brain cells also become infected and are eventually killed by the virus. Pretreatment with nerve growth factor (NGF) produces an initial protection from viral cell destruction, but does not block the final, lethal effect of the virus. These investigations demonstrate that sympathetic nerve cell destruction can be induced in newborn rodents by HSV, and that NGF treatment renders the cells, for a time-limited period, more resistant to the virus.

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New Zealand albino rabbits were inoculated in the right superior cervical ganglion with 25 microliter of herpes simplex virus type 1 (HSV-1) (McKrae strain; 10(3) or 10(5) PFU/ml). Positive tear film swabs were detected at least once in 28/32 (88%) of ipsilateral eyes and 6/32 (19%) of contralateral eyes beginning on postinoculation (PI) day 2-6. The average HSV-1 titer in the tear film was 4.0 X 10(3) PFU in ipsilateral eyes and 2.7 X 10(3) PFU in contralateral eyes, determined from eye washes after inoculation of 25 PFU of HSV-1. In selected rabbits, the aqueous humor was positive for virus on PI days 3, 4, 5, 6, and 8. the aqueous humor in ipsilateral eyes showed positive results in 9/11 (82%) of the eyes tapped on PI 3, 13/18 (72%) on PI 4, 5/11 (45%) on PI 5, 1/6 (17%) on PI 6, and 1/2 (50%) on PI 8. No virus was detected in aqueous humor tappings in any contralateral eyes (0/65). Conjunctivitis and iritis (iris hyperemia) appeared in all ipsilateral eyes beginning as early as PI day 1. Conjunctivitis occurred in 1/21 (4.8%) of contralateral eyes. Cells and flare appeared in 18/21 (86%) of ipsilateral eyes and 2/21 (9.5%) of contralateral eyes. Hyphema was noted in 3/21 (14%) of ipsilateral eyes. Of the eyes with iritis, 12/21 (57%) developed corneal edema. Corneal dendritic ulcers were observed in 4/21 (19%) of ipsilateral eyes and 2/21 (9.5%) of contralateral eyes. No ocular fundus changes were seen in any contralateral or ipsilateral eyes.(ABSTRACT TRUNCATED AT 250 WORDS)

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Newborn rat dissociated sympathetic neurons were grown in a chamber culture system, where a Teflon ring sealed with silicon grease separated the axonal plexus from the corresponding nerve cell bodies. The binding of 35S-labeled herpes virus suis (HVS) to the neurites was partially inhibited by an excess of unlabeled HVS as well as by concanavalin A, indicating the presence of specific binding sites for the virus. Specific binding was a prerequisite for the subsequent uptake and retrograde transport of HVS to the nerve cell bodies. Predominantly free nucleocapsids were detected by electron microscopy in the axons at the time of retrograde transport, both in culture and in vivo, suggesting the possibility that nucleocapsids without lipid membrane and not contained in cellular membrane compartments can be transported by retrograde axonal transport.

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