Acute Herpes Simplex Virus Infection Research Articles

Neonatal herpes: case series in two obstetric centres over a 10-year period (2013-2023), France.

Neonatal herpes simplex virus (HSV) infection (HSV infection in infants less than 6weeks of age) is rare but mortality and morbidity rates are high after disseminated disease and encephalitis.In France, the epidemiology is poorly described, and two decades ago, incidence was estimated to be 3 per 100,000 live births a year. We describe determinants, epidemiologic and clinical characteristics of neonatal HSV infection in a managed-care population attending in two major obstetric and paediatric centres, Paris, France, over a 10-year period. This retrospective case series study was conducted from 2013 to 2023, in infants less than 42days of age who had virologically confirmed HSV infection. We report an overall rate of neonatal herpes of 5.5 per 100,000 live births a year and an incidence of symptomatic cases of 1.2 per 100,000 live births a year. HSV-1 was the major serotype involved (84.2%) and post-natal acquisition through the orolabial route reached 63.2%. All neonates who had neonatal HSV PCR screening (owing to clinical signs in parents) and who received prompt acyclovir treatment remained asymptomatic. Symptomatic forms accounted for 21.1% cases of the total and mortality was high (62.5% of symptomatic forms). Conclusion: This case series confirms that neonates at risk for HSV disease and poor outcome are those born to HSV-seronegative mothers, preterm infants, and those who received acyclovir after onset of symptoms (mainly because mothers did not present evidence of acute HSV infection). Our study confirms the major role of HSV-1 and the frequency of its early post-natal acquisition. What is known: •Neonatal herpes simplex virus infection is rare but motality and morbidity rates are high after disseminted disease and encephalitis. National recommendations exist worldwide but mangement of this disease is not always easy. What is new: •As in France epidemiology of neonatal herpes is poorly described, our report is potentially an important addition to the existing literature. Moreover, we describe local practice that may be useful to physicians.

Histological Properties of Placentas in Acute Herpes Simplex Virus Infection Affecting Genitals

Acute herpes simplex virus infection in pregnant women results in intrauterine infection of the fetus in 45–50% of cases, thus being the cause of septic complications and severe somatic and neurological disorders in the newborn.The aim of the study was to investigate the placentas of new mothers with newly diagnosed herpes simplex virus type 2 infection (HSV-2) using histological and immunochemical methods.Material and methods. This histological study included 10 placentas of new mothers after operative delivery by caesarean section with newly diagnosed HSV-2 infection. The comparison group (control) consisted of 10 placentas of women with a physiological pregnancy. Histological sections of the placenta were stained with hematoxylin and eosin, Giemsa's solution and Picro-Mallory staining. Identification of the pro- and antiinflammatory phenotype of macrophages (CD68, CD163), subpopulations of CD4 and CD8 lymphocytes, TLR4 receptor expression was performed by immunohistochemical method using specific antibodies. Quantification of the cell population and TLR4 receptors was performed morphometrically. The data obtained were statistically analysed using MS Excel (2016) and SPSS Statistics 17.0.Results. Morphological manifestations of acute herpes simplex virus infection were combined inflammatory and compensatory in nature in the third trimester of pregnancy. The histological picture of the fetal part of the placenta demonstrated a decreased number of M2 (antiinflammatory) macrophages and an increased number of M1 (pro-inflammatory) macrophages. The imbalance between CD163+ and CD68+ profiles of placental macrophages with the numerical predominance of the latter evidenced a pronounced cellular immune response; this, in turn, was supported by intense TLR4 immunopositive staining of the fetal part of the placenta. There was perivillous fibrin deposition of varying degrees, villus agglutination, and necrosis of trophoblast cells associated with a relatively small population of CD4+ and CD8+. Villitis of viral etiology was characterized by destructive infiltration of maternal CD8+ T-lymphocytes penetrating the chorionic villi, combined with activated macrophages in the villi of the fetal part of the placenta. Modifications in the proportion of immune cells during HSV-2 infection supported cytotoxic and autoimmune reactions in the placenta in response to HSV-2 introduction.Conclusion. The results obtained evidence the development of a pronounced immunopathological process in the tissues of the fetal part of the placenta, which results in the decreased protective and compensatory properties of the placenta and increases risk of perinatal complications.

CANDIDATE OF MEDICINE, SENIOR RESEARCHER OF THE DEPARTMENT OF NEUROINFECTIONS OF L. HROMASHEVSKYI INSTITUTE OF EPIDEMIOLOGY AND INFECTION DISEASES OF THE NATIONAL ACADEMY OF MEDICAL SCIENCES OF UKRAINE

Background. Central nervous system tuberculosis is one of the most severe forms of extra-pulmonary tuberculosis. Tuberculous meningoencephalitis (TBM) is highly prevalent globally in resource-limited countries and in patients with immunosuppression. We present here a case of meningoencephalitis with proved acute Herpes simplex virus infection. However, our patient responded to antituberculosis therapy. This raises the possibility that some cases of “idiopathic” (cryptogenic) meningoencephalitis may represent occult tuberculosis disease.
 Result. A 22-year-old woman was admitted to our hospital because of fever, headache and hallucinations. Neck stiffness and other meningeal symptoms were present. CSF examination showed lymphocyte-dominant pleocytosis and a decreased level of glucose. Both Herpes simplex virus type 1 (HSV-1) DNA and IgG antibodies to the virus were found in the CSF sample. Although antibiotics and acyclovir were administered, fever, disturbance of consciousness, hallucinations and meningeal signs intensified. A second CSF sample obtained a week after the collection of the first one contained higher level of cytosis and so called “spider-web” cloth (SWC). As a result, the diagnosis was revised: tuberculosis was regarded as the most likely cause of the disease. The patient started receiving antituberculous treatment. Soon after the medications were changed, the meningoencephalitis started to subside and was finally cured. Judging from the clinical features, the CSF and MRI findings, the effectiveness of antituberculous drugs, the final diagnosis was made as tuberculous meningoencephalitis. From all these things, we conclude when even antibodies for Herpes viruses and viral DNA are present in the CSF of the patient with sterile meningoencephalitis the possibility of latent involvement in the process of Koch bacteria (KB) should be kept in mind.
 Conclusion. The patient’s symptoms and signs began to resolve with antituberculous therapy. Resolution of the lesions was confirmed by magnetic resonance imaging. We conclude that this case represented occult tuberculous disease. An empiric trial of antituberculous therapy may be used in other cases of apparently idiopathic meningoencephalitis.

EHMTI-0127. Three faces of pain-herpes zooster ophthalmicus

Background Herpes zoster ophthalmicus (HZO) occurs only the people who have been previously infected with varicella zooster virus (VZV). Primary infection is a chickenpox (95% VZV seropositivive in US adults). Reactivated forms its dormant status is the dorsal root, cranial nerve and other sensory ganglia may lay for years to decades. Reactivation of latens VZV localizated cutaneous rash erupting a single dermatome. It may travel along a sensory axon of the skin from vesicular lesions. Perineuritis causes intensive pain in the nerve distributionLifetime reactivation of VZV as shingles 50% incidence, HZO is rare (10-20%) of all VZV causes. HZO is a trigeminal manifestation of VZV. Reactivated VZV travels down V/1 and V/2 centripetal distribution. Contagious spread of the VZV may lead of the involvement of the other cranial nerves resulting optic neuropathy (II) isolated cranial nerve palsies (III. IV. especially IV.) neurogene motility disorders. Predisposing factors: immunecompromissed condition (decreased T-cell activity), acute herpes simplex virus infection and other reacting factors. Complications 50% of HZO patient is a postherpetic neuralgia (20% of a cases) involves the orbit (10-25% of a cases). Acute management: antiviral agent immediately-best prognosis started early-within 72 hours and general measures, ophthalmology consultation. Pain management: acute and postherpetic neuralgia. Our patient evaluated for left sided facial pain, unilateral “burning eye” and malaise that began two days ago. The neurological examination has been proven partially n. oculomotorius palsy of the left side and hyperaesthesia in dermatome V/1 unilateral side. Neuroimaging studies (cerebral and orbital CT and MRI) have shown normal status. Two days later on the face in the V/1 and V/2 dermatome we detected special characteristic skin symptom.

Evaluation of commercial herpes simplex virus IgG and IgM enzyme immunoassays

Serological methods are used widely for the determination of herpes simplex virus (HSV) IgG and IgM antibodies in virological laboratories. The present study evaluates the automated performance of the Virion\\Serion (Würzburg, Germany) and Orgentec (Mainz, Germany) enzyme-linked immunosorbent assays (ELISA) for the determination of HSV type-common and type-specific IgG and IgM antibodies. Two hundred sixty-three sera from HSV-negative children, healthy blood donors as well as patients without and with acute HSV infections were included. The Serion ELISAs classic HSV 1+2, HSV 1 and HSV 2 IgG showed sensitivities between 89.1% and 98.0% and specificities from 82.8% to 100%. Sensitivities of the Orgentec ELISAs Anti-HSV-1 and Anti-HSV-2 IgG were calculated as 91.0–96.0% and 88.5–95.4% accompanied by specificities between 93.1% and 100%. The HSV type-common Serion IgM ELISA revealed also a high sensitivity and specificity. However, the single-type HSV-1 and HSV-2 IgM ELISAs from both companies did not detect reliably HSV-1- and HSV-2-specific IgM antibodies. In conclusion, the automated performance of Serion ELISAs classic HSV 1+2, HSV 1 and HSV 2 IgG as well Orgentec ELISAs Anti-HSV-1 and Anti-HSV-2 IgG provide highly dependable results for identifying HSV-1 and HSV-2 IgG-positive or -negative individuals. While HSV type-common IgM ELISAs can be useful to confirm acute newly acquired HSV infections, the use of single-type IgM ELISAs on the basis of whole-virus antigen is dispensable.

Herpes simplex ulcerative esophagitis in healthy children

Herpes simplex virus is a common cause of ulcerative esophagitis in the immunocompromised or debilitated host. Despite a high prevalence of primary and recurrent Herpes simplex virus infection in the general population, Herpes simplex virus esophagitis (HSVE) appears to be rare in the immunocompetent host. We report three cases of endoscopically-diagnosed HSVE in apparently immunocompetent children; the presentation was characterized by acute onset of fever, odynophagia, and dysphagia. In two cases, the diagnosis was confirmed histologically by identification of herpes viral inclusions and culture of the virus in the presence of inflammation. The third case was considered to have probable HSVE based on the presence of typical cold sore on his lip, typical endoscopic finding, histopathological evidence of inflammation in esophageal biopsies and positive serologic evidence of acute Herpes simplex virus infection. Two cases received an intravenous course of acyclovir and one had self-limited recovery. All three cases had normal immunological workup and excellent health on long-term follow-up.

Herpes Simplex and Eosinophilic Oesophagitis: The Chicken or the Egg?

Herpes Simplex and Eosinophilic Oesophagitis: The Chicken or the Egg?

Identification of Replication-competent HSV-1 Cgal+ Strain Signaling Targets in Human Hepatoma Cells by Functional Organelle Proteomics

In the present work, we have attempted a comprehensive analysis of cytosolic and microsomal proteomes to elucidate the signaling pathways impaired in human hepatoma (Huh7) cells upon herpes simplex virus type 1 (HSV-1; Cgal(+)) infection. Using a combination of differential in-gel electrophoresis and nano liquid chromatography/tandem mass spectrometry, 18 spots corresponding to 16 unique deregulated cellular proteins were unambiguously identified, which were involved in the regulation of essential processes such as apoptosis, mRNA processing, cellular structure and integrity, signal transduction, and endoplasmic-reticulum-associated degradation pathway. Based on our proteomic data and additional functional studies target proteins were identified indicating a late activation of apoptotic pathways in Huh7 cells upon HSV-1 Cgal(+) infection. Additionally to changes on RuvB-like 2 and Bif-1, down-regulation of Erlin-2 suggests stimulation of Ca(2+)-dependent apoptosis. Moreover, activation of the mitochondrial apoptotic pathway results from a time-dependent multi-factorial impairment as inferred from the stepwise characterization of constitutive pro- and anti-apoptotic factors. Activation of serine-threonine protein phosphatase 2A (PP2A) was also found in Huh7 cells upon HSV-1 Cgal(+) infection. In addition, PP2A activation paralleled dephosphorylation and inactivation of downstream mitogen-activated protein (MAP) kinase pathway (MEK(1/2), ERK(1/2)) critical to cell survival and activation of proapoptotic Bad by dephosphorylation of Ser-112. Taken together, our results provide novel molecular information that contributes to define in detail the apoptotic mechanisms triggered by HSV-1 Cgal(+) in the host cell and lead to the implication of PP2A in the transduction of cell death signals and cell survival pathway arrest.

HERPES SIMPLEX VIRUS-IgM SPECIFIC ANTIBODIES IN GUILLAIN-BARRÉ SYNDROME AND ENCEPHALITIS

Herpes simplex virus (HSV) has veen associated with a variety of inflammatory neurologic disorders. Recently we studied a patient with Guillain-Barré syndrome (GBS) following acute herpes vaginalis infection. Since IgM virus-specific antibody is thought to be a reliable indicator of acute viral infection, we employed a 2-h serologic assay for serum IgM antibodies to HSV using an indirect immunofluorescent technique. This patient demonstrated high serum IgM titers to HSV type 2 during the acute phase of her neurologic syndrome. The titer dropped substantially as convalescence progressed. A search for similar elevations in HSV-IgM specific antibody was made on sera from more than 70 other GBS patients. No other significant IgM antibody titers to either HSV type 1 or type 2 were found in this GBS series and a large number of neurologic controls. However, sera from two patients with a presumptive diagnosis of acute herpes encephalitis based on clinical and cerebrospinal fluid findings were positive, showing high titers in our test. The results of this study suggest that associated acute HSV infection is uncommon in GBS and an immunofluorescent seroassay of the type reported here may be a valuable noninvasive technique enabling the clinical laboratory to rapid confirm a diagnosis of herpes encephalitis.

Reply:

We thank Drs. Cholongitas, Holubek, and colleagues for their interest in our work. Drs. Holubek et al. express concern about the potential inclusion of subjects with acute viral hepatitis (A, B, or C) or a concomitant idiosyncratic drug reaction. Obtaining an accurate medication history can be difficult; however, all medical records were carefully reviewed and the patient, their caregivers, and their providers were interviewed. Our prior publication demonstrated that occult HBV infection was not present in any patients with indeterminate ALF or other identifiable causes of ALF.1 Included subjects all had negative serologies. Overall, 27 subjects were excluded from the analysis for the following reasons: insufficient data (10), possible ischemic hepatitis (5), polysubstance abuse (3), concomitant acute hepatitis A virus infection (2), recent isoflurane anesthesia (2), concomitant acute herpes simplex virus infection (1) or acute hepatitis B virus infection (1), concomitant isoniazid use (1), metastatic cancer (1), and non-acetaminophen ALF (1). In addition, all of the included acetaminophen overdose cases had a clinical phenotype consistent with severe acetaminophen hepatotoxicity. Therefore, we feel that all of the cases included in our study and the conclusions reached are valid and accurate. Lastly, we have demonstrated that presence of acetaminophen-cysteine protein adducts in the blood may be a sensitive and specific biomarker for acetaminophen-induced ALF and provide a confirmatory, objective laboratory test in cases of diagnostic uncertainty (Davern, et al.2). The data provided by Cholongitas et al. are consistent with our findings. Table 1 shows the comparison of 3 prognostic models using our dataset. The King's criteria did not predict clinical outcomes well in our population. Dr. O'Grady's editorial suggests this is because of the common use of prophylactic fresh frozen plasma (FFP) in the United States. Use of prophylactic FFP is not common in U.S. transplant/specialty centers, and we discourage its use except for active bleeding or for invasive procedures (e.g., intracranial monitor placement). About 80% of subjects in the study were transferred from other institutions, and 54% had received FFP prior to transfer. In those who did not receive FFP, the likelihood ratio of the Kings' criteria for predicting death/need for transplant was 5.3 (sensitivity 32%, specificity 94%), compared to 2.3 (sensitivity 23%, specificity 90%) for those who had received FFP. Therefore, use of FFP prior to enrollment only modestly compromised the prognostic utility of the King's criteria. In our dataset, as well as that of Cholongitas et al., prognosis was best predicted by presence of multi-organ failure rather than the disease-specific King's criteria. We did not include arterial lactate collection in the protocol when the study was started in 1998, but have subsequently begun collecting these new data. A new prognostic score including readily available laboratory tests such as arterial lactate, serum phosphate, alpha-fetoprotein, and/or Gc Globulin levels in addition to the Kings criteria or other multi-organ failure indices may prove worthwhile.3-5 In the interim, efforts at reducing the increasing incidence of unintentional acetaminophen related ALF in the United States are needed to prevent future cases of this potentially life-threatening but avoidable illness. Anne M. Larson*, Robert J. Fontana , Timothy J. Davern , William M. Lee§, * Dept. of Internal Medicine, University of Washington, Seattle, WA, Dept. of Internal Medicine, University of Michigan, Ann Arbor, MI, Dept. of Internal Medicine, UCSF, San Francisco, CA, § Dept. of Internal Medicine, UT-Southwestern, Dallas, TX.

Absence of tumour necrosis factor facilitates primary and recurrent herpes simplex virus-1 infections.

Tumour necrosis factor (TNF) is an important cytokine in the innate immune response against various infections, including herpes simplex virus (HSV) infection. It has recently become a molecular target of anti-cytokine treatment in certain inflammatory diseases. TNF depletion resulted in a more rapid emergence of infectious HSV-1 in the explant cultures of latently infected trigeminal ganglia (TG), compared with controls. To further evaluate the importance of TNF in the host's defence responses against HSV-1, TNF-knockout mice were challenged via scarified cornea. These mice were more susceptible to primary acute corneal HSV-1 infection than controls, as manifested by an increased mortality rate and higher infectious virus titres in the eyes and TG, indicating that TNF is critical for defence during acute HSV infection. These results imply that the administration of anti-inflammatory TNF antagonists might facilitate the propagation of infectious HSV, resulting in an exacerbation of primary and recurrent acute lesions.

Rapid fulminant liver failure after anal exposure to genital herpes: a case report

Fulminant hepatic failure from herpes simplex virus (HSV) in immunocompetent individuals has been reported but is quite rare. We present an unusual case of acute HSV infection transmitted anally causing fatal hepatitis in a young individual with no apparent immunosuppressive illness. A 44 year-old previously healthy female with a past history significant only for asthma and shingles presented with a five day history of diarrhea, anorexia, arthralgias, diffuse abdominal pain and high grade fever (105F). Three days prior to her becoming ill the patient had anal intercourse with her boyfriend who had active genital herpes. Her primary care physician started the patient on oral ciprofloxacin. Her symptoms worsened and she was admitted. Diagnostic work-up revealed WBC of 5.0 103/ul, ALT- 221 IU/L, AST-527 IU/L, total bilirubin of 2.3mg/dl, alkaline phosphatase (ALK) of 189-IU/L, Albumin of 2.5g/dl, INR of 1.7, negative serologies or titers for hepatitis A, B, C; CMV, HIV, syphilis and ANA. Microbiologic work-up was unremarkable. The patient began to deteriorate clinically and developed acute respiratory distress syndrome as well as abdominal ascites. Transjugular liver biopsy was performed which revealed subacute hepatocyte necrosis involving 15–20% of the submitted tissue with marked polymorphonuclear infection and inclusion bodies. The patient was transferred to our facility. On examination, the patient was tachypneic and was found to have a scattered discrete vesicular rash on her face/torso/extremities as well as a protuberant abdomen with percussion tenderness in the right upper quadrant. Labs revealed a total bilirubin of 8.8 (direct 8.7), AST- 296, ALT-430, ALK- 190, creatinine of 4.2mg/dl and an INR of 2.3. The liver biopsy was re-evaluated and immunostains for HSV I and II were positive. The patient was intubated and aggressive supportive care in the ICU was initiated including therapy with acyclovir. She developed multi-organ failure and expired after 2 weeks. Thus we present an unusual case of acute fulminant hepatic failure secondary to genital herpes infection after anal exposure. Hepatitis caused by HSV infection carries a very high mortality, which is unchanged with institution of acyclovir (except if it is started very early) and even worsened by liver transplantation, which is therefore contraindicated.

Herpes simplex virus infection of murine sensory ganglia induces proliferation of neuronal satellite cells.

Herpes simplex virus (HSV) is a virtually ubiquitous human pathogen that, following cutaneous infection, latently infects neurons of sensory ganglia. Satellite cells (SCs) ensheath and provide metabolic support for these neurons, and could potentially participate in controlling HSV disease. Although SCs are restrictive for HSV replication, hypercellularity of non-neuronal cells in ganglia is prominent during HSV infection in animal models. SCs proliferate in response to trauma, e.g. nerve cut or crush, but it is not known if proliferation occurs in response to viral infection. To address this issue, cell proliferation, measured by bromodeoxyuridine (BrdU) uptake, and immune infiltrate, measured by CD45 labelling, were examined during acute infection in a mouse model. Because SCs do not express CD45, the BrdU(+) CD45(-) cell subset represents the proliferating SC population. We report that during acute ganglionic HSV infection there is a substantial increase in SC numbers. We suggest that SC proliferation in response to HSV infection may occur in order to facilitate neuronal survival.

Role of CD28/CD80-86 and CD40/CD154 costimulatory interactions in host defense to primary herpes simplex virus infection.

Dependence of the primary antiviral immune response on costimulatory interactions between CD28/CD80-86 and between CD40/CD154 (CD40 ligand) has been correlated with the extent of viral replication in two models of systemic infection, lymphocytic choriomeningitis virus and vesicular stomatitis virus. To determine the role of these costimulatory interactions in the context of an acute cytolytic, but locally replicating viral infection, herpes simplex virus (HSV) infection was assessed in mice that had the CD28/CD80-86 or CD40/CD154 interactions disrupted either genetically or with blocking reagents (CTLA4Ig and MR1, respectively). CTLA4Ig treatment greatly reduced paralysis-free survival during primary acute HSV infection. This reflected an almost total ablation of the anti-HSV CD4(+) and CD8(+) T-cell responses due to anergy and reduced cell numbers, respectively. Disruption of CD40/CD154 interactions impaired survival, but the effect was less severe than that observed in CTLA4Ig-treated mice, with reductions observed in the CD4(+) T-cell but not CD8(+) T-cell responses. These two costimulatory pathways functioned in part independently, since disruption of both further impaired survival. The dependence on these costimulatory interactions for the control of primary HSV infection may represent a more widespread paradigm for nonsystemic viruses, which have restricted sites of replication and which employ immunoevasive measures.

Herpes simplex virus vaccines

Herpes simplex virus (HSV) infections are common and produce not only a primary infection, but also latent and recurrent infections. Therefore, the goals of a HSV vaccine are different from other vaccines. In this review, the goals of both prophylactic and therapeutic HSV vaccines are discussed and related to the immunobiology of acute and recurrent HSV infections. Next, the vaccine strategies that have been and are being evaluated for control of HSV disease are described. Current approaches take advantage of many of the modern methodologies for vaccine development. Thus, as we await final evaluations of subunit HSV glycoprotein vaccines, early phase I trails are evaluating newer vaccine approaches including DNA-based vaccines and replication-impaired viruses. The definitive HSV vaccine may await increased knowledge of the optimal viral antigen(s) and routes to induce genital tract immunity.

Distribution of tumor necrosis factor receptor messenger RNA in normal and herpes simplex virus infected trigeminal ganglia in the mouse

Purpose: to investigate the distribution of p55 and p75 tumor necrosis factor (TNF) receptor mRNA in normal murine trigeminal ganglia, and in murine trigeminal ganglia acutely infected with McKrae strain herpes simplex virus (HSV). Methods: in situ hybridization with antisense 35S-labeled riboprobes for mRNA encoding both the p55 and p75 TNF receptor (TNFR) subtypes was used in normal and HSV-infected murine trigeminal ganglia. Sense riboprobes were used as controls. Results: in situ hybridization with both p55 and p75 riboprobes produced a strong autoradiographic signal over many, but not all, trigeminal sensory neurons. Signal for mRNA encoding both TNFR subtypes was also present over the arachnoid layers surrounding trigeminal ganglia. Acute ocular HSV infection was accompanied by an intense leukocytic infiltrate into the ophthalmic portion of the trigeminal ganglia, and, in this setting, increased p55 and p75 mRNA signal was closely related to the location and number of infiltrating white blood cells. The distribution and number of trigeminal sensory neurons expressing mRNA for the two TNFR subtypes did not appear to change following infection. Signal over control sections hybridized with sense p55 and p75 TNFR cRNA probes was comparable to background. Conclusions: the observed distribution of p55 and p75 TNFR mRNA over trigeminal sensory neurons and over the arachnoid layers surrounding trigeminal ganglia supports suggestions that TNF has a direct effect on neurons, either as a neuromodulator or neurotrophic factor, and that TNF may play a central role in blood-brain barrier regulation. Increased signal for TNFR mRNA in acutely infected trigeminal ganglia appears to reflect infiltration by receptor-bearing white blood cells.

Neuronal sprouting in mouse sensory ganglia infected with herpes simplex virus type 2 (HSV-2): induction of growth-associated protein (GAP-43) and ultrastructural evidence.

Herpes simplex virus (HSV) is neurotropic and when inoculated on the mouse footpad is retrogradely transported to the associated dorsal root ganglia (DRG), where infection is established. Previous observations suggest that, after HSV infection, sensory ganglion neurons may mount a sprouting response. In our HSV-infected DRG model, we investigate this issue by (1) examining expression of growth-associated protein (GAP-43), a molecule known to be induced by growing axons, and (2) determining ultrastructurally whether HSV-infected dorsal roots contain neurites. In a time course study, we show that GAP-43 is induced both in HSV-infected DRG and their central processes. The increase in GAP-43 is first seen 2 weeks following unilateral footpad inoculation in both cell bodies and dorsal roots, and is sustained at 1 month post inoculation in roots but not in perikarya. Large bundles of unmyelinated small caliber axons, lacking Schwann cell ensheathment, are observed by electron microscopy in dorsal roots 2 weeks and 1 month following inoculation. These profiles resemble developing or regenerating neurites and are rarely seen in roots of mock-infected or uninfected controls. The increased GAP-43 immunoreactivity and ultrastructural changes shown here, in conjunction with previously documented selective neuropeptide and enzyme alterations, confirm that a sprouting response is mounted in sensory ganglia following acute HSV infection.

Attempted modulation of herpes simplex virus (HSV) infection of neurons in culture by fibroblast growth factor.

It has been suggested that fibroblast growth factor (FGF) receptors may mediate entry of herpes simplex virus (HSV) to susceptible cells. We investigated the possible modulation of acute lytic HSV infection of cultured rat neurons by basic FGF, using cell-specific markers and indirect immunostaining. Dissociated neural cell cultures were prepared from the medial septal region of the basal forebrain, the hippocampus and dorsal root ganglion (DRG). The proportion of neurons in the cultures was enhanced by the addition of cytosine arabinoside (2 microM) in the hippocampal and DRG cultures and by inversion of the coverslips in septal cultures. The percentage of MAP2+ and neurofilament+ neurons in these cultures varied between 9 and 95%. Cultures were treated with basic FGF (4-5 ng ml-1) continuously and infected with wild-type HSV-1, untreated uninfected cultures acting as controls. Both FGF binding and FGF receptors were demonstrated in hippocampal, and to a much lesser extent, DRG neurons. In repeated experiments it was found that FGF treatment did not have a significant effect on lytic infection in any of the neuronal populations studied as assessed by the development of viral antigen expression and comparison of identified neurons in FGF, treated versus untreated, infected cultures. Our data show that FGF does not have a 'neuroprotective' effect on HSV infection of either central or peripheral neurons.

Control of Acute Cutaneous Herpes Simplex Virus Infection: T Cell-Mediated Viral Clearance Is Dependent upon Interferon-γ (IFN-γ)

It is well established that T lymphocytes play a critical role in the control and clearance of herpes simplex virus (HSV) infections. However, the role of the CD4 + and CD8 + T cell subsets in the recovery process has not been clearly elucidated. Cutaneous HSV infection of the footpad tissue of C57BL/6 (B6) mice provides a model to determine the relative contribution of each T cell subset during the important early phase of the response to infection. In this study, we observed that the elimination of mature peripheral T lymphocytes by depletion in vivo with a combination of CD4- and CD8-specific monoclonal antibodies prevented recovery from acute infection in this model. However, mice depleted of either the CD4 + or CD8 + subpopulation alone recovered completely, with only a slight delay in the total clearance of infectious virus, Adoptive transfer studies revealed that lymph node cells from donor mice selectively depleted of either CD4 + or CD8 + T cell subset in vivo, or from normal donors selectively depleted in vitro, were able to mediate recovery. As CD4-depleted mice fail to generate a CD8 + T cell-mediated cytolytic T lymphocyte (CTL) response, this suggested that the control of cutaneous HSV infections may be mediated by a cytokine-dependent mechanism common to both the CD4 + and CD8 + T cell subpopulations. It was subsequently found that the neutralization of IFN-γ in vivo diminished the ability of mice to clear infectious HSV from the skin, and treatment with anti-IFN-γ in vivo ablated the ability of transferred T cells to mediate recovery. These studies suggested that IFN-γ-mediated mechanisms play a critical role in the control of and recovery from acute cutaneous HSV infection.

Effects of the immunomodulating agent R837 on acute and latent herpes simplex virus type 2 infections

R837 is an immune modulator with no in vitro activity against herpes simplex virus (HSV). We evaluated topical R837 as therapy for genital HSV type 2 infection using the guinea pig model of this disease. Furthermore, we investigated the effect of R837 therapy on acute and latent neural HSV infections. Therapy initiated 12 h after viral inoculation and given twice a day significantly reduced the acute neural infection so that HSV was recovered from only 1 of 64 neural tissue specimens obtained from R837 recipients compared with 43 of 56 specimens obtained from placebo recipients (P less than 0.0001). R837 initiated 36 h after HSV inoculation and given once a day also significantly reduced the total mean lesion score of the acute disease from 14.1 +/- 4.3 to 2.6 +/- 5.3 (P less than 0.0001) and shortened the period of vaginal HSV shedding from 6.9 +/- 1.7 to 3.2 +/- 1.4 days (P less than 0.001). R837-treated animals also developed fewer HSV recurrences than did controls (2.0 +/- 1.7 versus 5.1 +/- 1.7; P less than 0.0002). Latent HSV was detected in 23 of 24 dorsal root ganglia explant cultures from placebo recipients but in only 2 of 30 cultures from R837-treated animals, and HSV in these 2 cultures was detectable only with the addition of a demethylating agent. Topical R837 exhibited in vivo anti-HSV activity, reducing both acute and latent neural infections as well as acute and recurrent genital disease.