Infection with herpes-simplex viruses 1 and 2. 3

An intrinsic network of polar interactions is responsible for binding of UL49.5 C-degron by the CRL2KLHDC3 ubiquitin ligase

Bovine herpesvirus type 1 (BoHV-1) is a pathogen of cattle responsible for infectious bovine rhinotracheitis. The BoHV-1 UL49.5 is a transmembrane protein that binds to the transporter associated with antigen processing (TAP) and downregulates cell surface expression of the antigenic peptide complexes with the major histocompatibility complex class I (MHC-I). KLHDC3 is a kelch domain-containing protein 3 and a substrate receptor of a cullin2-RING (CRL2) E3 ubiquitin ligase. Recently, it has been identified that CRL2KLHDC3 is responsible for UL49.5-triggered TAP degradation via a C-degron pathway and the presence of the degron sequence does not lead to the degradation of UL49.5 itself. The molecular modeling of KLHDC3 in complexes with four UL49.5 C-terminal decapeptides (one native protein and three mutants) revealed their activity to be closely correlated with the conformation which they adopt in KLHDC3 binding cleft. To analyze the interaction between UL49.5 and KLHDC3 in detail, in this work a total of 3.6 μs long molecular dynamics simulations have been performed. The complete UL49.5-KLHDC3 complexes were embedded into the fully hydrated all-atom lipid membrane model with explicit water molecules. The network of polar interactions has been proposed to be responsible for the recognition and binding of the degron in KLHDC3. The interaction network within the binding pocket appeared to be very similar between two CRL2 substrate receptors: KLHDC3 and KLHDC2.

Association of Viral Infections With Oral Cavity Lesions: Role of SARS-CoV-2 Infection

Different viral agents, such as herpesviruses, human papillomavirus, and Coxsackie virus, are responsible for primary oral lesions, while other viruses, such as human immunodeficiency virus, affect the oral cavity due to immune system weakness. Interestingly, it has been reported that coronavirus disease 2019 (COVID-19) patients can show cutaneous manifestations, including the oral cavity. However, the association between oral injuries and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is still unclear. This narrative review aimed to summarize the available literature and provide an overview of oral lesions associated with COVID-19. An online literature search was conducted to select relevant studies published up to November 2020. The results of 17 studies showed variability in oral lesions associated with COVID-19, including ulcerations, aphthous-like lesions, and macules. The tongue, lips, and palate were the most frequent anatomical locations. According to current knowledge, the etiopathogenesis of multiple COVID-19-associated lesions seems to be multifactorial. The appearance of such lesions could be related to the direct or indirect action of SARS-CoV-2 over the oral mucosa cells, coinfections, immunity impairment, and adverse drug reactions. Nevertheless, COVID-19-associated oral lesions may be underreported, mainly due to lockdown periods and the lack of mandatory dispositive protection. Consequently, further research is necessary to determine the diagnostic and pathological significance of oral manifestations of COVID-19. All medical doctors, dentists, and dermatologists are encouraged to perform an accurate and thorough oral examination of all suspected and confirmed COVID-19 cases to recognize the disease's possible early manifestations.

Termination of Transcription of LAT Increases the Amounts of ICP0 mRNA but Does Not Alter the Course of HSV-1 Infection in Latently Infected Murine Ganglia

On entering sensory ganglia, herpes simplex viruses 1 (HSV-1) establishes a latent infection with the synthesis of a latency associated transcript (LAT) or initiates productive infection with expression of a set of immediate early viral proteins. The precise mechanisms how expression of α genes is suppressed during the latency are unknown. One mechanism that has been proposed is illustrated in the case of ICP0, a key immediate early viral regulatory protein. Specifically, the 2 kb LAT intron is complementary to the 3' terminal portion of ICP0 mRNA. To test the hypothesis that accumulation of LAT negatively affects the accumulation of ICP0 mRNA, we inserted a DNA fragment encoding two poly(A) sequences into LAT to early terminate LAT transcript without interrupting the complementary sequence of ICP0 transcript (named as SR1603). Comparisons of the parent (SR1601) and mutant (SR1603) HSV-1 viruses showed the following: Neurons harboring latent SR1603 virus accumulated equivalent amounts of viral DNA but higher amounts of ICP0 mRNA and lower amounts of LAT, when compared to neurons harboring the SR1601 virus. One notable difference between the two viruses is that viral RNA accumulation in explanted ganglia harboring SR1603 virus initiated significantly sooner than that in neurons harboring SR1601 virus, suggesting that ICP0 may act as an activator of viral gene expression in permissive cells. Collectively, these data suggest that increased ICP0 mRNA by suppressed LAT did not affect the establishment of latency in latently infected murine ganglia.

A case of herpes simplex virus pneumonia detected by sputum cytodiagnosis

A sputum test is noninvasive and simple. It contributed to correct diagnosis of a patient with severe acute respiratory failure. We again point out the usefulness of sputum cytodiagnosis for differentiating severe pneumonia.

The Problem of Herpetic Whitlow Among Hospital Personnel

Five cases of nosocomially acquired herpetic whitlow are presented; three cases developed following a common exposure. All infections were acquired despite the use of surgical gloves as recommended by existing guidelines on control of nosocomial infection. In two cases the mistaken diagnosis of pyogenic paronychia led to surgical intervention, with excessive morbidity and disability. Among the five cases, morbidity ranged from several days of unemployment to permanent sequelae necessitating a career change. Revised guidelines for infection control should include the use of gloves on both hands whenever patient care involves contact with a debilitated patient with herpes simplex labialis.

Large Amounts of Reactivated Virus in Tears Precedes Recurrent Herpes Stromal Keratitis in Stressed Rabbits Latently Infected with Herpes Simplex Virus

AIM

Recurrent herpetic stromal keratitis (rHSK), due to an immune response to reactivation of herpes simplex virus (HSV-1), can cause corneal blindness. The development of therapeutic interventions such as drugs and vaccines to decrease rHSK have been hampered by the lack of a small and reliable animal model in which rHSK occurs at a high frequency during HSV-1 latency. The aim of this study is to develop a rabbit model of rHSK in which stress from elevated temperatures increases the frequency of HSV-1 reactivations and rHSK.

MATERIALS AND METHODS

Rabbits latently infected with HSV-1 were subjected to elevated temperatures and the frequency of viral reactivations and rHSK were determined.

RESULTS

In an experiment in which rabbits latently infected with HSV-1 were subjected to ill-defined stress as a result of failure of the vivarium air conditioning system, reactivation of HSV-1 occurred at over twice the normal frequency. In addition, 60% of eyes developed severe rHSK compared to <1% of eyes normally. All episodes of rHSK were preceded four to five days prior by an unusually large amount of reactivated virus in the tears of that eye and whenever this unusually large amount of reactivated virus was detected in tears, rHSK always appeared 4-5 days later. In subsequent experiments using well defined heat stress the reactivation frequency was similarly increased, but no eyes developed rHSK.

CONCLUSIONS

The results reported here support the hypothesis that rHSK is associated not simply with elevated reactivation frequency, but rather with rare episodes of very high levels of reactivated virus in tears 4-5 days earlier.

The modulation of phosphatase expression impacts the proliferation efficiency of HSV-1 in infected astrocytes

Herpes Simplex Virus 1 (HSV-1) is a major pathogen that causes human neurological diseases, including herpes simplex encephalitis (HSE). Previous studies have shown that astrocytes are involved in HSV-1 systemic pathogenesis in the central nervous system (CNS), although the mechanism remains unclear. In this study, a high-throughput RNAi library screening method was used to analyze the effect of host phosphatase gene regulation on HSV-1 replication using Macaca mulatta primary astrocytes in an in vitro culture system. The results showed that the downregulation of five phosphatase genes (PNKP, SNAP23, PTPRU, LOC714621 and PPM1M) significantly inhibited HSV-1 infection, suggesting that these phosphatases were needed in HSV-1 replication in rhesus astrocytes. Although statistically significant, the effect of downregulation of these phosphatases on HSV-1 replication in a human astrocytoma cell line appears to be more limited. Our results suggest that the phosphatase genes in astrocytes may regulate the immunological and pathological reactions caused by HSV-1 CNS infection through the regulation of HSV-1 replication or of multiple signal transduction pathways.

Social support and socioeconomic status interact to predict Epstein-Barr virus latency in women awaiting diagnosis or newly diagnosed with breast cancer

OBJECTIVE

Both higher socioeconomic status (SES) and supportive personal relationships confer health benefits, including better immune function. This study assessed the joint impact of SES and social support on the expression of a latent herpesvirus, Epstein-Barr virus (EBV), in a group of highly stressed women.

METHODS

Two-hundred and twenty four women either awaiting further evaluation following an abnormal mammogram or newly diagnosed with breast cancer completed questionnaires and provided blood samples to assess EBV viral capsid antigen (VCA) IgG antibody titers.

RESULTS

More highly educated women with more support from friends had lower EBV VCA antibody titers, reflecting a stronger cellular immune response to the latent virus; however, among less educated women, friend support was not associated with EBV antibody titers. As revealed in an ancillary analysis, more highly educated women with more friend support had lower systolic blood pressure (SBP); however, friend support was not associated with SBP among less educated women. Neither depression nor perceived stress mediated these associations. Neither cancer status nor cancer stage among those diagnosed with cancer was significantly related to these outcomes.

CONCLUSION

Lower SES women may not reap the same immunological benefits from friend support when experiencing a stressful life event as their higher SES counterparts.

Escape of herpesviruses from the nucleus

The nuclear envelope of eukaryotic cells is composed of double lipid-bilayer membranes, the membrane-connected nuclear pore complexes and an underlying nuclear lamina network. The nuclear pore complexes serve as gates for regulating the transport of macromolecules between cytoplasm and nucleus. The nuclear lamina not only provides an intact meshwork for maintaining the nuclear stiffness but also presents a natural barrier against most DNA viruses. Herpesviruses are large DNA viruses associated with multiple human and animal diseases. The complex herpesviral virion contains more than 30 viral proteins. After viral DNA replication, the newly synthesised genome is packaged into the pre-assembled intranuclear capsid. The nucleocapsid must then transverse through the nuclear envelope to the cytoplasm for the subsequent maturation process. Information regarding how nucleocapsid breaches the rigid nuclear lamina barrier and accesses the inner nuclear membrane for primary envelopment has emerged recently. From the point of view of both viral components and nuclear structure, this review summarises recent advances in the complicated protein-protein interactions and the phosphorylation regulations involved in the nuclear egress of herpesviral nucleocapsids.

Identification of herpes simplex virus type 1 proteins encoded within the first 1.5 kb of the latency-associated transcript

Expression of the first 1.5 kb of the latency-associated transcript (LAT) that is encoded by herpes simplex virus type 1 (HSV-1) is sufficient for wild-type (wt) levels of reactivation from latency in small animal models. Peptide-specific immunoglobulin G (IgG) was generated against open reading frames (ORFs) that are located within the first 1.5 kb of LAT coding sequences. Cells stably transfected with LAT or trigeminal ganglionic neurons of mice infected with a LAT expressing virus appeared to express the L2 or L8 ORF. Only L2 ORF expression was readily detected in trigeminal ganglionic neurons of latently infected mice.

Towards an understanding of the herpes simplex virus type 1 latency-reactivation cycle

Infection by herpes simplex virus type 1 (HSV-1) can cause clinical symptoms in the peripheral and central nervous system. Recurrent ocular shedding can lead to corneal scarring and vision loss making HSV-1 a leading cause of corneal blindness due to an infectious agent. The primary site of HSV-1 latency is sensory neurons within trigeminal ganglia. Periodically, reactivation from latency occurs resulting in virus transmission and recurrent disease. During latency, the latency-associated transcript (LAT) is abundantly expressed. LAT expression is important for the latency-reactivation cycle in animal models, in part, because it inhibits apoptosis, viral gene expression, and productive infection. A novel transcript within LAT coding sequences (AL3) and small nonprotein coding RNAs are also expressed in trigeminal ganglia of latently infected mice. In this review, an update of viral factors that are expressed during latency and their potential roles in regulating the latency-reactivation cycle is discussed.

Two small RNAs encoded within the first 1.5 kilobases of the herpes simplex virus type 1 latency-associated transcript can inhibit productive infection and cooperate to inhibit apoptosis

The herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) is abundantly expressed in latently infected trigeminal ganglionic sensory neurons. Expression of the first 1.5 kb of LAT coding sequences is sufficient for the wild-type reactivation phenotype in small animal models of infection. The ability of the first 1.5 kb of LAT coding sequences to inhibit apoptosis is important for the latency-reactivation cycle. Several studies have also concluded that LAT inhibits productive infection. To date, a functional LAT protein has not been identified, suggesting that LAT is a regulatory RNA. Two small RNAs (sRNAs) were previously identified within the first 1.5 kb of LAT coding sequences. In this study, we demonstrated that both LAT sRNAs were expressed in the trigeminal ganglia of mice latently infected with an HSV-1 strain that expresses LAT but not when mice were infected with a LAT null mutant. LAT sRNA1 and sRNA2 cooperated to inhibit cold shock-induced apoptosis in mouse neuroblastoma cells. LAT sRNA1, but not LAT sRNA2, inhibited apoptosis less efficiently than both sRNAs. When rabbit skin cells were cotransfected with plasmids that express LAT sRNA1 and HSV-1 genomic DNA, the amount of infectious virus released was reduced approximately 3 logs. Although LAT sRNA2 was less effective at inhibiting virus production, it inhibited expression of infected cell protein 4 (ICP4). Neither LAT sRNA had an obvious effect on ICP0 expression. These studies suggested that expression of two LAT sRNAs plays a role in the latency-reactivation cycle by inhibiting apoptosis and productive infection.

Identification of a novel herpes simplex virus type 1 transcript and protein (AL3) expressed during latency

The herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) is abundantly expressed in latently infected sensory neurons. In small animal models of infection, expression of the first 1.5 kb of LAT coding sequences is necessary and sufficient for wild-type reactivation from latency. The ability of LAT to inhibit apoptosis is important for reactivation from latency. Within the first 1.5 kb of LAT coding sequences and LAT promoter sequences, additional transcripts have been identified. For example, the anti-sense to LAT transcript (AL) is expressed in the opposite direction to LAT from the 5' end of LAT and LAT promoter sequences. In addition, the upstream of LAT (UOL) transcript is expressed in the LAT direction from sequences in the LAT promoter. Further examination of the first 1.5 kb of LAT coding sequences revealed two small ORFs that are anti-sense with respect to LAT (AL2 and AL3). A transcript spanning AL3 was detected in productively infected cells, mouse neuroblastoma cells stably expressing LAT and trigeminal ganglia (TG) of latently infected mice. Peptide-specific IgG directed against AL3 specifically recognized a protein migrating near 15 kDa in cells stably transfected with LAT, mouse neuroblastoma cells transfected with a plasmid containing the AL3 ORF and TG of latently infected mice. The inability to detect the AL3 protein during productive infection may have been because the 5' terminus of the AL3 transcript was downstream of the first in-frame methionine of the AL3 ORF during productive infection.

Chorioretinitis of the newborn with herpes simplex virus type 1. Report of a case

A disseminated herpes simplex virus (HSV) infection involving the central nervous system and accompanied by chrioretinitis in a a 3-week-old girl is described. The aetiologic diagnosis was established on the basis of vrius isolated from skin vesicles, and a significant rise in complement fixing antibodies to HSV type 1. The mode of transmission of the virus to the infant apparently was direct contact with an oral lesion in the mother, that was present at the time of delivery. The patient survived but became blind and microcephalic, with severe neurological sequelae. The virus isolated was identified as HSV type 1, which is an infrequent finding in herpetic chorioretinitis of the newborn.

Loss of mandibular lymph node integrity is associated with an increase in sensitivity to HSV-1 infection in CD118-deficient mice

Type I IFNs are potent antiviral cytokines that contribute to the development of the adaptive immune response. To determine the role of type I IFNs in this process in an infectious disease model, mice deficient in the type I IFN receptor (CD118(-/-)) were ocularly infected with HSV-1 and surveyed at times post infection in the nervous system and lymph node for virus and the host immune response. Virus titers were elevated in the trigeminal ganglia and brain stem with virus disseminating rapidly to the draining lymph node of CD118(-/-) mice. T cell and plasmacytoid dendritic cell infiltration into the brain stem was reduced in CD118(-/-) mice following infection, which correlated with a reduction in CXCL10 but not CXCL9 expression. In contrast, CXCL1 and CCL2 levels were up-regulated in the brainstem of CD118(-/-) mice associated with an increase in F4/80(+) macrophages. By day 5 post infection, there was a significant loss in T, NK, and plasmacytoid dendritic cell numbers in the draining lymph nodes associated with an increase in apoptotic/necrotic T cells and an appreciable lack of HSV-specific CD8(+) T cells. The adoptive transfer of HSV-specific TCR transgenic CD8(+) T cells into CD118(-/-) mice at the time of infection modestly reduced viral titers in the nervous system suggesting in addition to the generation of HSV-specific CD8(+) T cells, other type I IFN-activated pathways are instrumental in controlling acute infection.

Human herpes simplex virus infections: epidemiology, pathogenesis, symptomatology, diagnosis, and management

Eight of the more than 80 known herpesviruses are human pathogens. Human herpes simplex virus (HSV) is a contagious infection with a large reservoir in the general population. It has a potential for significant complications in the immunocompromised host. In addition, psychological distress caused by the negative stigma associated with genital herpes and visible facial lesions in those experiencing frequent outbreaks renders it a challenging clinical dilemma. This article reviews the epidemiology, pathogenesis, and diagnostic features of HSV infections, providing the clinician with an up-to-date understanding of the available management strategies for mucocutaneous HSV-induced disease.

Wanderings of a DNA enzymologist: from DNA polymerase to viral latency

I am a member of what has been called, perhaps too grandiosely, "The Greatest Generation." I grew up during the Great Depression and served in the U.S. Army during World War II. Because of my military service and the benefits of the GI Bill, I was able to attend college and, later, graduate school. Early in my graduate studies, I became fascinated with enzymes and the biochemical reactions that they catalyze. This fascination has never left me during the 50 years I have been a "DNA enzymologist." I was fortunate to have had as a mentor Arthur Kornberg, one of the great biochemists of the twentieth century, and a splendid group of postdocs and graduate students. I have studied DNA polymerases, DNA nucleases, DNA ligases, and DNA recombinases, enzymes that are critical to our understanding of DNA replication, repair, and recombination. Most recently, I have been studying herpes virus replication and inadvertently wandered into an entirely new area-viral latency.

Comparative study of ocular herpes simplex virus in patients with and without self-reported atopy

PURPOSE

To compare the characteristics of ocular herpes simplex virus (HSV) in patients with and without atopy.

DESIGN

Retrospective cohort comparative study.

METHODS

Patients who presented at the Cornea Service, Wills Eye Hospital, between March 2003 and March 2004 who had been previously diagnosed in the same institution as having ocular HSV diagnosis or were just diagnosed as having the disease were asked to complete a study questionnaire that enabled categorization into atopic and nonatopic. In April 2005, 223 patients who agreed to be in the study had their charts reviewed, and 125 patients were excluded according to exclusion criteria: immunosuppression, follow-up less than one year, previous history of penetrating keratoplasty (PK) out of the Cornea Service, and no active HSV episode during follow-up.

MAIN OUTCOME MEASURES

Incidence of all types of HSV recurrences.

SECONDARY OUTCOME MEASURES

Bilaterality, visual loss, need for PK , and secondary bacterial infection in both groups. HSV episodes were classified into infectious, inflammatory, and mixed for analysis.

RESULTS

Ninety eight patients (110 eyes) were included in the study. Atopic/nonatopic (P value): the mean follow-up was 11.6 (+/- 10.6)/8.8 years (+/- 8.4) (P = .14); the mean incidence of HSV episodes per year of follow-up was: total episodes 0.32 (+/- 0.36)/0.28 (+/- 0.33) (P = .14), infectious 0.16 (+/- 0.22)/0.10 (+/- 0.14) (P < .01), inflammatory 0.11 (+/- 0.19)/0.11 (+/- 0.19) (P < .01), and mixed 0.09 (+/- 0.20)/0.07 (+/- 0.16) (P = .06); bilateral HSV was present in 9/3 patients (P = .22); the mean loss of vision was four lines of Snellen in both groups; PK was performed in 14 of 16 eyes (P = .45); secondary bacterial infection was present in two of four eyes (P = .26).

CONCLUSIONS

Atopic patients had considerably more infectious and fewer inflammatory episodes when compared with nonatopics.

The herpes simplex virus type 1 locus that encodes the latency-associated transcript enhances the frequency of encephalitis in male BALB/c mice

Herpes simplex virus type 1 (HSV-1) is the leading cause of virus-induced encephalitis; however, the viral genes that regulate encephalitis have not been well characterized. In this study, we tested whether the LAT (latency-associated transcript) locus regulates the frequency of encephalitis in male or female mice. Male BALB/c mice are more susceptible to HSV-1-induced encephalitis than age-matched female BALB/c mice. Deletion of LAT coding sequences reduced the frequency of encephalitis. A recombinant virus containing the first 1.5 kb of the LAT coding sequence induces levels of encephalitis in male BALB/c mice similar to those induced by wild-type HSV-1.

Herpes simplex virus in pregnancy: new concepts in prevention and management

Genital herpes simplex virus (HSV) infection is one of the most common viral sexually transmitted diseases in the United States. It is estimated that 45 million adolescents and adults are infected with genital HSV. Most genital herpes infections in the United States are caused by HSV type 2 (HSV-2), and 25% to 30% of women of reproductive age have HSV-2 antibodies. What is more striking is that genital herpes is frequently under-recognized, and that only 5% to 10% of these women have a history of genital herpes. Because such a small percentage of women are aware of being infected with HSV, the risk of maternal transmission of this virus to the fetus or newborn is a significant health issue.

Activation of c-Jun N-terminal kinase (JNK) pathway by HSV-1 immediate early protein ICP0

The immediate early protein ICP0 encoded by herpes simplex virus 1 (HSV-1) is believed to activate transcription and consequently productive infection. The precise mechanisms of ICP0-mediated transactivation are under intensive study. Here, we demonstrate that ICP0 can strongly activate AP-1 responsive genes specifically. This activation is inhibited by c-Jun (S73A), c-Jun (S63/73A), TAK1 (K63W), but not by p38 (AF), ERK1 (K71R), ERK2 (K52R) and TRAF6 (C85A/H87A). We further investigate the relevancy of ERK, JNK and p38 MAPK pathways using their respective inhibitors PD98059, SP600125 and SB202190. Only SP600125 significantly attenuates the AP-1 responsive gene activation by ICP0. Consistent with these, the JNK is remarkably activated in response to ICP0, and this JNK activation is shown to be significantly attenuated by TAK1 (K63W). It turns out that ICP0 interacts specifically with TAK1 and stimulates its kinase activity. These findings reveal a new molecular mechanism ICP0 explores to regulate gene expression.

The locus encompassing the latency-associated transcript of herpes simplex virus type 1 interferes with and delays interferon expression in productively infected neuroblastoma cells and trigeminal Ganglia of acutely infected mice

The herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) is the only abundant viral transcript expressed in latently infected neurons. LAT inhibits apoptosis, suggesting that it regulates latency by promoting the survival of infected neurons. The LAT locus also contains a newly described gene (AL), which is antisense to LAT and partially overlaps LAT encoding sequences. When human (SK-N-SH) or mouse (neuro-2A) neuroblastoma cells were infected with a virus that does not express LAT or AL gene products (dLAT2903), beta interferon (IFN-beta) and IFN-alpha RNA expression was detected earlier relative to the same cells infected with HSV-1 strains that express LAT and AL. Infection of neuro-2A cells with dLAT2903 also led to higher levels of IFN-beta promoter activity than in cells infected with wild-type (wt) HSV-1. In contrast, IFN RNA expression was the same when human lung fibroblasts were infected with dLAT2903 or wt HSV-1. When BALB/c mice were infected with dLAT2903, IFN-alpha and IFN-beta RNA expression was readily detected in trigeminal ganglia (TG) 4 days after infection. These transcripts were not detected in TG of mice infected with wt HSV-1 or dLAT2903R (marker-rescued dLAT2903) until 6 days postinfection. When TG single-cell suspensions from infected BALB/c mice were prepared and incubated in vitro with wt HSV-1 as a source of antigen, TG cultures prepared from mice infected with dLAT2903 produced and secreted higher levels of IFN protein than wt HSV-1 or dLAT2903R. Collectively, these studies suggest that the LAT locus interferes with and delays IFN expression.

Recurrent herpes simplex virus type 2 infection of the hand complicated by persistent lymphoedema

A 33-year-old, immunocompetent woman had recurrent herpes simplex virus reactivation of the right hand presenting with a cellulitis-like picture. She continued to have monthly debilitating recrudescences for more than 3 years until an adequate dosage of prophylactic antiviral therapy was achieved. After 2 years of repeated episodes she had chronic dull pain and developed persistent acquired lymphoedema of the left hand and forearm, which is an extremely rare complication. This case highlights the need for herpes simplex infection of the hand to be included in the differential diagnosis of bacterial cellulitis in order for appropriate and prompt therapy to be achieved.

Herpes simplex virus type 2 infection is a risk factor for hypertension

Herpes simplex virus type 2 (HSV-2), which has been recognized as a potential cardiovascular pathogen and implicated in carotid atherosclerosis and coronary artery disease, is independently associated with the future risk of cardiovascular death. Investigations have demonstrated that hypertension may be related to inflammation, and inflammation is one of the symptoms of HSV-2 infection. This cross-sectional study investigated the correlation between HSV-2 infection and essential hypertension. One thousand two hundred and forty four inpatients (488 patients with essential hypertension and 756 normotensives) were investigated serologically for the specific immunoglobulin G (IgG) to HSV-2 by enzyme-linked immunosorbent assay. Patients diagnosed with pheochromocytoma, primary aldosteronism, aorto-arteritis or renal artery stenosis were excluded. The prevalence of HSV-2 IgG seropositivity was significantly higher in the hypertensive group than in the normotensive group (38.3% vs. 29.8%, p =0.002). After adjustment for confounding factors, an association of HSV-2 IgG seropositivity with essential hypertension was found on binary logistic regression analysis. The adjusted odds ratio of essential hypertension was 1.4 (95% confidence intervals, 1.1 to 1.8; p =0.005) for HSV-2 infection; the adjusted covariates included age, male sex, smoking, body mass index, dyslipidemia, diabetes and coronary artery disease. The results of this study indicated that HSV-2 infection might be an independent risk factor for essential hypertension.

Cunnilingus and vaginal intercourse are risk factors for herpes simplex virus type 1 acquisition in women

OBJECTIVE

Although numerous cross-sectional studies have identified herpes simplex virus type 1 (HSV-1) as an important genital pathogen, the specific sexual activities associated with HSV-1 infection are not well delineated. Our objective was to identify demographic and behavioral variables in women associated with the prevalence and acquisition of HSV-1.

STUDY

From 1998 through 2000, we enrolled 1207 nonpregnant 18- to 30-year-old women from 3 Pittsburgh, Pennsylvania, area health clinics in a prospective cohort study. Serum from the women was tested each visit for the presence of type-specific HSV-1 antibodies.

RESULTS

At enrollment, HSV-1 serum antibodies were detected in only 38% of women < or =20 years of age. Black race, < or =12 years education, older age, and a history of at least 5 lifetime male sex partners were independently associated with the prevalence of HSV-1. In longitudinal analyses, women who had vaginal intercourse were more likely than sexually inactive women to acquire HSV-1 (6.8 vs. 1.2 cases per 100 woman-years of follow up; P=0.05). Similarly, women who only had receptive oral sex, without vaginal intercourse, were also more likely than sexually inactive women to acquire HSV-1 (9.8 vs. 1.2 cases per 100 woman-years of follow up; P=0.04).

CONCLUSIONS

Receiving cunnilingus and vaginal intercourse are important risk factors for the acquisition of HSV-1 among young women. Genital herpes prevention strategies will need to consider both the increased susceptibility for HSV-1 acquisition that young adults now have at sexual debut and the important contributions of HSV-1 to the burgeoning genital herpes epidemic.

Presence of viremia in patients with primary herpetic gingivostomatitis

BACKGROUND

Presence of viremia during primary herpes simplex virus (HSV) infections has been previously investigated, but the findings for immunocompetent individuals have only rarely been reported.

METHODS

With use of polymerase chain reaction (PCR), we evaluated blood samples obtained from children with primary herpes simplex virus (HSV) gingivostomatitis for viremia.

RESULTS

There were 16 girls and 16 boys, aged 9-44 months (median age, 19 months). Serological test results for HSV type 1 were positive for 3 subjects (10.3%), borderline for 7 (24.1%), and negative for 19 (65.5%). Results of PCR of peripheral blood samples were positive for 11 subjects (34.4%). Time from disease onset to specimen collection was 24-216 h (median, 72 h) and was longer for subjects with positive results of serological tests (P =.014) and shorter for subjects with positive PCR results (P=.42). No cases with positive results of both PCR and serological tests were found.

CONCLUSION

PCR detected viremia in 34% of patients with primary herpetic gingivostomatitis. Presence of viremia may play a potential role in viral dissemination, providing a better understanding of the pathogenesis of HSV infections, especially of the central nervous system.

[The latest in herpes simplex keratitis therapy]

Herpetic keratitis is characterized by spontaneous recurrences and a risk of vision loss, the latter being more serious when relapses are frequent and severe. Two clinical forms are commonly distinguished: epithelial keratitis, usually quickly resolved with topical antivirals, and stromal keratitis, which has a slower progression, even when both steroids and antivirals are used. Great strides have been made during the last 20 Years in the therapy of herpes keratitis, which is now considered and treated as a chronic disease. Randomized controlled studies definitively showed the decrease in spontaneous herpetic ocular events in patients treated with long-term oral acyclovir. The effectiveness of preventive treatment has also been shown during high-risk periods, especially ocular surgery, in patients with a history of herpes keratitis. However, the optimal duration and dosage of antiviral prevention have yet to be defined. We can also hope that in the future novel antiviral strategies such as vaccination will reduce the place of herpes keratitis as an indication for corneal graft.

The neural F-box protein NFB42 mediates the nuclear export of the herpes simplex virus type 1 replication initiator protein (UL9 protein) after viral infection

The neural F-box 42-kDa protein (NFB42) is a component of the SCF(NFB42) E3 ubiquitin ligase that is expressed in all major areas of the brain; it is not detected in nonneuronal tissues. We previously identified NFB42 as a binding partner for the herpes simplex virus 1 (HSV-1) UL9 protein, the viral replication-initiator, and showed that coexpression of NFB42 and UL9 in human embryonic kidney (293T) cells led to a significant decrease in the level of UL9 protein. We have now found that HSV-1 infection promotes the shuttling of NFB42 between the cytosol and the nucleus in both 293T cells and primary hippocampal neurons, permitting NFB42 to bind to the phosphorylated UL9 protein, which is localized in the nucleus. This interaction mediates the export of the UL9 protein from the nucleus to the cytosol, leading to its ubiquitination and degradation via the 26S proteasome. Because the intranuclear localization of the UL9 protein, along with other viral and cellular factors, is an essential step in viral DNA replication, degradation of the UL9 protein in neurons by means of nuclear export through its specific interaction with NFB42 may prevent active replication and promote neuronal latency of HSV-1.

Herpes simplex virus in the respiratory tract of critical care patients: a prospective study

BACKGROUND

Herpes simplex virus (HSV) is occasionally detected in the lower respiratory tract of patients in intensive care, but its clinical importance in such situations remains unclear. We did a prospective cohort study to define the prevalence, origin, risk factors, and clinical relevance of HSV in the respiratory tract of patients undergoing critical care.

METHODS

We tested 764 patients admitted to intensive care for the presence of HSV in the respiratory tract, and assessed statistical relations between this virus and clinical variables.

FINDINGS

HSV was detected by oropharyngeal swab in the upper respiratory tract of 169 (22%) of 764 patients, within 10 days of admission for 150 (89%) of these individuals. The virus was isolated in 58 (16%) of 361 patients whose lower respiratory tract was sampled. The presence of HSV in the throat was a risk factor for development of HSV infections in the lower respiratory tract (p<0.001). HSV was isolated most frequently in patients with severe disease. HSV in the throat was associated with acute respiratory distress syndrome (p<0.001) and with increased length of stay in intensive care (p<0.001).

INTERPRETATION

Our data suggest that HSV reactivation or infection of the upper respiratory tract is frequent among patients in intensive care, and is a risk factor for development of lower respiratory tract infection with this virus, possibly by means of aspiration.

Replication-initiator protein (UL9) of the herpes simplex virus 1 binds NFB42 and is degraded via the ubiquitin-proteasome pathway

The ubiquitin-proteasome pathway plays a critical role in the degradation of short-lived and regulatory proteins in a variety of cellular processes. The F-box proteins are part of the ubiquitin-ligase complexes, which mediate ubiquitination and proteasome-dependent degradation of phosphorylated proteins. We previously identified NFB42, an F-box protein that is highly enriched in the nervous system, as a binding partner for the herpes simplex virus 1 UL9 protein, the viral replication-initiator protein, in a yeast two-hybrid screen. In the present work, we find that coexpression of NFB42 and UL9 genes in 293T cells leads to a significant decrease in the level of UL9 protein. Treatment with the 26S-proteasome inhibitor MG132 restores the UL9 protein to normal levels. We have observed also that the UL9 protein is polyubiquitinated in vivo and that the interaction between NFB42 and the UL9 protein is dependent upon phosphorylation of the UL9 protein. These results suggest that the interaction of the UL9 protein with NFB42 results in its polyubiquitination and subsequent degradation by the 26S proteasome. They suggest further a mechanism by which latency of herpes simplex virus 1 can be established in neuronal cells.

Herpes simplex virus type 1 and bovine herpesvirus 1 latency

Primary infection by herpes simplex virus type 1 (HSV-1) can cause clinical symptoms in the peripheral and central nervous system, upper respiratory tract, and gastrointestinal tract. Recurrent ocular shedding leads to corneal scarring that can progress to vision loss. Consequently, HSV-1 is the leading cause of corneal blindness due to an infectious agent. Bovine herpesvirus 1 (BHV-1) has similar biological properties to HSV-1 and is a significant health concern to the cattle industry. Latency of BHV-1 and HSV-1 is established in sensory neurons of trigeminal ganglia, but latency can be interrupted periodically, leading to reactivation from latency and spread of infectious virus. The ability of HSV-1 and BHV-1 to reactivate from latency leads to virus transmission and can lead to recurrent disease in individuals latently infected with HSV-1. During latency, the only abundant HSV-1 RNA expressed is the latency-associated transcript (LAT). In latently infected cattle, the latency-related (LR) RNA is the only abundant transcript that is expressed. LAT and LR RNA are antisense to ICP0 or bICP0, viral genes that are crucial for productive infection, suggesting that LAT and LR RNA interfere with productive infection by inhibiting ICP0 or bICP0 expression. Numerous studies have concluded that LAT expression is important for the latency-reactivation cycle in animal models. The LR gene has recently been demonstrated to be required for the latency-reactivation cycle in cattle. Several recent studies have demonstrated that LAT and the LR gene inhibit apoptosis (programmed cell death) in trigeminal ganglia of infected animals and transiently transfected cells. The antiapoptotic properties of LAT map to the same sequences that are necessary for promoting reactivation from latency. This review summarizes our current knowledge of factors regulating the latency-reactivation cycle of HSV-1 and BHV-1.

Ethnic variation in type of genital herpes simplex virus infection in a South London genitourinary medicine clinic

The aims of this study were to investigate the prevalence of herpes simplex virus (HSV) types 1 and 2 in the study population and correlate the results with clinical and demographic details. Consecutive HSV isolates from 334 clinic attendees were typed by immunofluorescence. Patient information was collected from the case notes. Overall, HSV-1 was isolated from 48 and HSV-2 from 287 samples, respectively. There was no significant difference in isolation rates according to gender. However, 33% of white patients' isolates typed as HSV-1, while only 6% of the isolates from the black population were HSV-1 (P < 0.001). Initial infections were seen in 81% of HSV-1 infections and 48% of HSV-2 infections, respectively. A wide discrepancy was observed in the prevalence of HSV-1 and HSV-2 infections between the ethnic groups in this population, which was not explained in terms of gender or age. This may reflect different exposure to HSV-1 in childhood or different sexual practices. The increased prevalence in genital HSV-1 reported in recent studies was not seen in this population. However, the differing proportions of primary and first episode infections may reflect a changing epidemiology.

Oligodendrocytes from human donors differ in resistance to herpes simplex virus 1 (HSV-1)

Primary cultures of human oligodendrocytes (HOLs) were established from six different donors. Differences in resistance to infection with herpes simplex virus 1 (HSV-1) were determined between the primary cultures of HOL in tissue culture infective dose 50 (TCID(50)), indirect immunofluoresence (IF), and serial electron microscopy (EM) studies. Virus production at different multiplicities of infection (MOIs) indicated that differences in HSV-1 replication were statistically significant and MOI-dependent. Overall, virus yield from the HOL cultures infected at an MOI of 1 increased up to 6 days postinfection (PI); no additional enhancement occurred at 7 days PI. However, differences in the replication capacity of the six HOL cultures observed at 5 days PI persisted at 6 and 7 days PI. When taken together, the results of these investigations indicate that, similar to experimental animals, resistance to HSV-1 differs between primary cultures of HOL and is donor-dependent. The results also raise the possibility that similar to experimental animals, resistance to HSV-1, mediated at the level of HOL, may be genetically determined. Furthermore, permissive infections of primary cultures of HOL were established with HSV-1 over a wide range of MOIs, similar to results obtained with viral infection of primary murine oligodendrocytes, but neither latent nor abortive infections of HOL were induced in vitro, even at very low MOIs. Resistance to HSV-1, mediated by glial cells, is a nonimmune mechanism that may influence the development of acute CNS infection in man as well as individual susceptibility to this virus.

Ultraviolet light induces reactivation in a murine model of cutaneous herpes simplex virus-1 infection

We have developed a model of cutaneous herpes simplex virus-1 (HSV-1) reactivation in SKH-1 hairless mice which closely mimics the condition in humans. Sixty plaque-forming units of HSV-1 strain 17 syn+ were applied to a superficially abraded area on the lateral body wall. More than 85% of mice developed primary HSV-1 infection characterized by a zosteriform pattern of cutaneous vesiculation and ulceration. Approximately one-third of mice with primary skin lesions succumbed to neurologic disease and in the remaining mice cutaneous lesions healed completely. Subsequent exposure of healed areas to two minimal inflammatory doses of UV resulted in recrudescence of skin lesions in the irradiated areas in almost 60% of mice. Lesions appeared approximately 4 days after irradiation, persisted for 3-5 days and then resolved completely. Reactivation rarely resulted in death due to neurologic disease. Primary lesions had a histologic appearance typical of cutaneous HSV-1 infection with vesicles and focal epithelial necrosis accompanied by the formation of epithelial syncytial cells and the presence of herpetic intranuclear inclusion bodies. In primary lesions HSV-1 was demonstrated by immunohistochemistry, polymerase chain reaction and culture. In reactivated lesions epithelial syncytia and inclusion bodies were not seen; however, virus was demonstrable by polymerase chain reaction and culture. Exposure of the uninfected side to UV did not stimulate disease recurrence suggesting that local effects of UV rather than systemic immunosuppression were responsible for reactivation. Reactivation could also be obtained with two minimal inflammatory doses of UV from a UV-340 light source which emits light approximating the solar spectrum.

First episodes of genital herpes in a Swedish STD population: a study of epidemiology and transmission by the use of herpes simplex virus (HSV) typing and specific serology

OBJECTIVES

To determine the proportion of herpes simplex virus type 1 (HSV-1) and HSV type 2 (HSV-2) in first episodes of genital herpes. To evaluate the use of HSV specific serology for classifying first episodes of genital herpes and for defining HSV serostatus in the patients' sexual partners.

METHODS

108 consecutive patients with first episodes of genital herpes seen at three STD clinics in Sweden from 1995 to 1999 were included in the study. HSV culture and typing were performed and serum was tested for antibodies against a type common HSV antigen and a type specific HSV-2 antigen, glycoprotein G2 (gG2). A structured interview including questions about sexual behaviour and sexual partners was taken. "Steady" partners were offered a blood test for HSV serology and counselling.

RESULTS

Of 108 patients, 11 had a negative HSV culture. Of the 97 who were HSV culture positive, 44% (43/97) were typed as HSV-1 and 56% (54/97) as HSV-2. For 86 of these 97 patients, HSV serology from the initial visit was available. Of 52 primary infections, thus initially seronegative, 64% were HSV-1 infections and of 19 female primary infections 16 (84%) were HSV-1. In 17% the first episode of genital herpes corresponded to the first clinical recurrence of an infection acquired earlier in life. There was a significant correlation between having orogenital sex and being infected with HSV-1 and also a history of labial herpes in the partner. Only 20% of partners of patients with an HSV-2 infection had a history of genital herpes.

CONCLUSIONS

Almost half of first episodes of genital herpes are caused by HSV-1. In young women with a primary genital infection, HSV-1 is much more frequent than HSV-2. Besides HSV typing, we found specific HSV serology of value for classifying first episodes and for diagnosing a subclinical HSV-2 infection in partners. Anamnestic data supported the suggestion that the orogenital route of transmission was common in genital HSV-1 infections.

Anti-herpes simplex virus activities of crude water extracts of Thai medicinal plants

A number of Thai medicinal plants, recommended as remedies for herpesvirus infection and have been used in primary health care were investigated for their intracellular activities against herpes simplex viruses (HSV). Centella asiatica L., Maclura cochinchinensis Cornor, and Mangifera indica L. contained both anti-HSV-1 and -2 activities, as determined by plaque inhibition assay. An inhibition of the production of infectious HSV-2 virions from infected Vero cells could also be demonstrated. Combinations of each of these reconstituted extracts with 9-(2-hydroxyethoxymethyl) guanosine (acyclovir; ACV) resulted either in subadditive, additive, or synergistic interaction, against HSV-2, depending on the dose of ACV used; mixture of C. asiatica and M. indica exerted an additive effect in a similar assay. Furthermore, the inhibitory effects of these plant extracts were also substantiated by flow cytometric analysis of virus-specific antigens in the infected cells. The active constituent present in C. asiatica extract was determined to be asiaticoside while in M. indica was mangiferin. Thus, these data suggest therapeutic potential of these plant extracts.

Prevalence of herpes simplex type 2 antibodies and a clinical history of herpes in three different populations in Campinas City, Brazil

OBJECTIVES

To determine the seroprevalence of herpes simplex virus type 2 (HSV-2) antibodies and the relation between the history of clinical herpes and the presence of type-specific HSV-2 antibodies in three different populations from the city of Campinas City, Brazil.

POPULATION AND METHODS

One hundred and one college students, 96 patients with sexually transmitted diseases (STD), and 102 women at delivery were interviewed and blood samples were collected. Total HSV (HSV-1 and HSV-2) antibodies were screened by enzyme-linked immunosorbent assay (ELISA) and type-specific HSV-2 antibodies were detected by Western blot assay.

RESULTS

Herpes simplex virus antibodies were detected in 66.3% of the students, 97.1% of the women at delivery, and 99.0% of the STD patients. Type-specific HSV-2 antibodies were detected in 6.9% of the students, 22.6% of the women at delivery, and in 53.1% of the STD patients. History of genital herpes was reported by none of the students, by one of the women at delivery, and by 11 of 51 (21.6%) STD patients who were HSV-2 seropositive. Four of the 45 (8.9%) seronegative STD patients reported a history of genital herpes.

CONCLUSION

The prevalence of HSV-2 infection in Campinas City can be significantly affected by the characteristics of the population studied, as was shown in previous studies. The sensitivity of the history of genital herpes was low in the present series, stressing that prophylactic measures for vertical and horizontal transmission of HSV-2 should not be based only on a positive history of genital ulcers.

Herpes simplex virus

Herpes simplex virus (HSV) infection is prevalent worldwide. Herpes labialis, caused predominantly by HSV-1, and herpes vulvovaginitis, caused predominantly by HSV-2, may result in significant morbidity and mortality for infected neonates exposed during delivery. The diagnosis of HSV infection is made by serological testing, viral culture, or polymerase chain reaction. Women with primary herpes vulvovaginitis exhibit a painful vesicular rash which is self-limited but may be followed by multiple recurrences. Women at greatest risk to transmit HSV to their neonates are those who experience their first episode of HSV during the latter stage of pregnancy. If infected, their neonates may have localized skin, eye and mucosal lesions, invasive central nervous system infection, or disseminated disease. Because of the potentially devastating outcome for a baby infected with HSV, pregnant women with active HSV lesions at delivery should be offered a cesarean section. Still, many neonates who are infected with HSV are born to women with asymptomatic HSV shedding. Therefore, prevention of HSV during pregnancy is exceedingly important.

Evaluation of antioxidant healing formulations in topical therapy of experimental cutaneous and genital herpes simplex virus infections

A genital HSV-2 infection of guinea pigs and a cutaneous HSV-1 infection in mice were used to examine the ability of antioxidant components CRT1 to reduce lesion development, duration, and severity. CRT is a patented antioxidant formulation developed by Warner-Lambert Worldwide Consumer Healthcare R. and D. CRT contains three components that work synergistically: vitamin E, sodium pyruvate and membrane stabilizing fatty acids. The MS strain of HSV-2 was utilized for intravaginal inoculation of guinea pigs with approximately 1.2 x 10(5) plaque forming units. The guinea pigs were treated on the external genital skin four times daily for 10 days beginning 48 h post viral inoculation. This study was designed to optimize the CRT formulations that would be used to quantify the synergistic effect of the CRT components. SKH-1 male hairless mice were inoculated with 1 x 10(7) HSV-1 (McIntyre strain) on the dorsal surface of the mouse and treated with CRT formulations starting on the afternoon of the day of infection, and treated for the following 14 days. In the guinea pig model, the CRT formula that contained all three CRT components, worked synergistically to reduce lesion development, duration and severity scores significantly compared to vehicle control or acyclovir. Acyclovir was the only compound that reduced viral titers, but in contrast to CRT, acyclovir did not reduce lesion development, duration or severity. The quantitative effect of the three CRT components was demonstrated in the mouse model.

Latent herpes simplex virus type 1 gene expression in ganglia innervating the human gastrointestinal tract

Using in situ hybridization, we demonstrated that latent herpes simplex virus type 1 (HSV-1) gene expression is prevalent in human adult nodose ganglia. This suggests that infection of gastrointestinal sensory nerves, probably through swallowed virus-laden oral secretions, occurs commonly and that HSV-1 reactivating from this site may play a role in recurrent gastrointestinal disorders.

Perinatal herpesvirus infections. Herpes simplex, varicella, and cytomegalovirus

The herpesvirus infections (herpes simplex, varicella, and cytomegalovirus) create many dilemmas when encountered during pregnancy. This article reviews the epidemiologic diagnosis and management of perinatal herpesvirus infections. A review of possible future trends is also included.

Patient recognition of recrudescent herpes labialis: a clinical and virological assessment

OBJECTIVES

The purpose of this study was to ascertain how accurate the general public was at diagnosing the condition of recrudescent herpes labialis.

METHODS

An advertisement was placed in a local newspaper inviting patients to attend the Oral Medicine Clinic as soon as they thought they developed the clinically evident stage of herpes labialis. At the clinic, patients were examined to confirm the clinical presence of herpes labialis and also had a swab of the lesion(s) taken for virus culture. Virus culture was by the HEP-2 culture technique capable of detecting both herpes simplex Type 1 and herpes simplex Type 2. Patients also completed a detailed questionnaire concerning their knowledge of herpes labialis.

RESULTS

In total, 41 patients attended for screening. The findings were that all patients had clinical herpes labialis, and herpes simplex virus was isolated in 96% of cases. In contrast, in only about 50% of cases were patients aware that their herpes labialis was caused by a virus.

CONCLUSIONS

The general public are very good at recognizing herpes labialis lesions but need to be given more information about their infectivity.

Oral inoculation with herpes simplex virus type 1 infects enteric neuron and mucosal nerve fibers within the gastrointestinal tract in mice

Herpes simplex virus type 1 (HSV-1) is commonly encountered first during childhood as an oral infection. After this initial infection resolves, the virus remains in a latent form within innervating sensory ganglia for the life of the host. We have previously shown, using a murine model, that HSV-1 placed within the lumen of the esophagus gains access to nerves within the gut wall and establishes a latent infection in sensory ganglia (nodose ganglia) of the tenth cranial nerve (R. M. Gesser, T. Valyi-Nagy, S. M. Altschuler, and N. W. Fraser, J. Gen. Virol. 75:2379-2386, 1994). Peripheral processes of neurons in these ganglia travel through the vagus nerve and function as primary sensory receptors in most of the gastrointestinal tract, relaying information from the gut wall and mucosal surface to secondary neurons within the brain stem. In the work described here, we further examined the spread of HSV-1 through the enteric nervous system after oral inoculation. By immunohistochemistry, HSV-1 was found to infect myenteric ganglia in Auerbach's plexus between the inner and outer muscle layers of the gut wall, submucosal ganglia (Meisner's plexus), and periglandular ganglion plexuses surrounding submucosal glands. Virus-infected nerve fibers were also seen projecting through the mucosal layer to interact directly with surface epithelial cells. These intramucosal nerve fibers may be a conduit by which intraluminal virus is able to gain access to the enteric nervous system from the gastrointestinal lumen.

Attenuation of the natural course of herpes simplex virus infection in human oral epithelial cell cultures by smokeless tobacco extracts suggests the possibility of a synergistic mechanism for carcinogenesis

High prevalence of both tobacco use and latent herpes simplex virus type 1 suggests the opportunity for synergism between these agents as cocarcinogens. In this study, postprimary human oral epithelial cell cultures were infected with herpes simplex virus type 1 pretreated with 2% extracts of either loose leaf, moist, or dry snuffs. Cultures were subsequently periodically exposed to the tobacco. Parameters measured included percentage of cultures undergoing active virus production, onset and time course of cytopathic effects, and concentration of virus released into the media over time. Results showed inhibition of both herpes simplex virus-mediated cell lysis and viral replication by tobacco extracts. This is the first time that these phenomena have been demonstrated in normal human oral epithelial cells. The work described here provides evidence to support a hypothesis that herpes simplex virus type 1 and smokeless tobacco may act synergistically in oral carcinogenesis.

Rapid detection of HSV with an enzyme-linked virus inducible system™ (ELVIS™) employing a genetically modified cell line

BACKGROUND

Infections with herpes simplex viruses (HSV) are common and may cause severe disease in immunocompromised hosts and in neonates. Isolation of infectious HSV in tissue culture is the most sensitive method of detection, but is not the most rapid. Recently, however, an Enzyme-Linked Virus Inducible System (ELVIS) for rapid detection of HSV in culture has been developed. The system employs genetically engineered baby hamster kidney (BHK) cells (ELVIS cells) whose DNA bears and HSV inducible promoter gene chimerically linked to an E. coli LacZ "reporter" gene. Induction of the promoter by HSV leads to the production of LacZ product, beta-galactosidase, which is readily detected histochemically.

OBJECTIVE

To evaluate these ELVIS cells, as a test for HSV, in comparison with HSV detection in MRC-5 cells in shell vial cultures confirmed by staining with fluorescent antibodies.

STUDY DESIGN

Over a period of one month, 167 specimens submitted to the laboratory for detection of HSV were evaluated. Specimens were inoculated onto MRC-5 cells growing on glass coverslips in each of two shell vials and into two wells of a 24-well cluster plate containing ELVIS cells. MRC-5 shell vial cultures were observed daily for cpe for up to 7 days. With the appearance of cpe, the coverslips were fixed and the cells were typed for HSV-1 and HSV-2 with monoclonal antibodies. Specimens inoculated onto ELVIS cells were incubated for 16-24 h, then substrate was added to stain for beta-galactosidase. ELVIS cells, induced by HSV infection to express beta-galactosidase, stained blue upon reaction with substrate.

RESULTS

Of 167 specimens inoculated onto MRC-5 cells, 13 were excluded because of contamination or toxicity. Among the remaining 154 specimens, 24 were positive for HSV in the MRC-5 shell vials. Of 166 specimens inoculated into the ELVIS cell, all were completed within 24 h. Twenty-three (23) of the 24 shell-vial-positive cultures also were positive on the ELVIS cells. All 23 specimens detected in the ELVIS cells were positive within 24 h, whereas only nine were positive within 24 hours in MRC-5 shell vial cultures. The remaining 15 became positive after 24 h. Specimens positive for viruses other than HSV-1 or HSV-2 were not positive on the ELVIS cells.

CONCLUSIONS

The ELVIS assay for HSV is simple to perform, is rapid, sensitive, and specific. The assay detects both HSV-1 and HSV-2. No antibodies are required unless typing, which can be done on the ELVIS cells, is necessary.