Causal association between inflammatory bowel disease and herpes virus infections: a two-sample bidirectional Mendelian randomization study.

Background: Previous observational or retrospective studies have suggested an association between inflammatory bowel disease (IBD) and herpes virus infections. Using Mendelian randomization (MR) approach, our objective was to determine whether there was a causal association between IBD and herpes virus infections. Methods: In genome-wide association study (GWAS) datasets of the International Inflammatory Bowel Disease Genetics Consortium, we obtained genetic instrumental variables for three phenotypes from 34,652 participants (12,882 IBD cases and 21,770 controls), 27,432 participants [6,968 ulcerative colitis (UC) cases and 20,464 controls], and 20,883 participants [5,956 Crohn's disease (CD) cases and 14,927 controls], respectively. Summary statistics for herpes virus infections (chickenpox, herpes zoster, and mononucleosis) were obtained from the FinnGen database. MR results were expressed as odds ratio (OR) with 95% confidence interval (CI). Results: Our study found no evidence of a causal effect of genetically predicted IBD on herpes virus infections [P value for inverse variance weighting (IVW): 0.063 to 0.652]. For the subtypes of IBD, UC had a suggestive association with mononucleosis (P value for IVW: 0.023). It appeared that CD was also weakly associated with mononucleosis (P value for IVW: 0.058; P value for Weighted median: 0.036). In addition, we found a suggestive causality for CD on chickenpox (P value for IVW: 0.038). Neither UC (P value for IVW: 0.574) nor CD (P value for IVW: 0.168) has a causal effect on herpes zoster. The results of the bidirectional MR analysis did not indicate that herpes virus infections were associated with IBD, UC or CD (P value for IVW: 0.239 to 0.888). Conclusion: This study showed a suggestive causality for both CD-chickenpox and UC-mononucleosis, despite no associations reaching a statistical significance value after corrections for multiple testing. There was no evidence of a causal association between IBD and its two subtypes on herpes zoster.

Acute zoster plasma contains elevated amyloid, correlating with Aß42 and amylin levels, and is amyloidogenic.

Herpes zoster is associated with an increased dementia and neovascular macular degeneration risk and a decline in glycemic control in diabetes mellitus. Because amyloid is present and pathogenic in these diseases, we quantified amyloid, Aß40, Aß42, and amylin in 14 zoster and 10 control plasmas. Compared with controls, zoster plasma had significantly elevated amyloid that correlated with Aß42 and amylin levels and increased amyloid aggregation with addition of exogenous Aß42 or amylin. These results suggest that zoster plasma contains factor(s) that promotes aggregation of amyloidogenic peptides, potentially contributing to the toxic amyloid burden and explaining accelerated disease progression following zoster.

Varicella-Zoster Virus (VZV) Small Noncoding RNAs Antisense to the VZV Latency-Encoded Transcript VLT Enhance Viral Replication.

Small noncoding RNAs (sncRNA), including microRNA (miR), are expressed by many viruses to provide an additional layer of gene expression regulation. Our work has shown that varicella-zoster virus (VZV; also called human herpesvirus 3 [HHV3]), the human alphaherpesvirus causing varicella and herpes zoster, expresses 24 virally encoded sncRNA (VZVsncRNA) in infected cells. Here, we demonstrate that several VZVsncRNA can modulate VZV growth, including four VZVsncRNA (VZVsncRNA10, -11, -12, and -13) that are antisense to VLT, a transcript made in lytic infections and associated with VZV latency. The influence on productive VZV growth and spread was assessed in epithelial cells transfected with locked nucleotide analog antagonists (LNAA). LNAA to the four VZVsncRNA antisense to VLT significantly reduced viral spread and progeny titers of infectious virus, suggesting that these sncRNA promoted lytic infection. The LNAA to VZVsncRNA12, encoded in the leader to ORF61, also significantly increased the levels of VLT transcripts. Conversely, overexpression of VZVsncRNA13 using adeno-associated virus consistently increased VZV spread and progeny titers. These results suggest that sncRNA antisense to VZV may regulate VZV growth, possibly by affecting VLT expression. Transfection of LNAA to VZVsncRNA14 and VZVsncRNA9 decreased and increased VZV growth, respectively, while LNAA to three other VZVsncRNA had no significant effects on replication. These data strongly support the conclusion that VZV replication is modulated by multiple virally encoded sncRNA, revealing an additional layer of complexity of VZV regulation of lytic infections. This may inform the development of novel anti-sncRNA-based therapies for treatment of VZV diseases.IMPORTANCE Varicella-zoster virus (VZV) causes herpes zoster, a major health issue in the aging and immunocompromised populations. Small noncoding RNAs (sncRNA) are recognized as important actors in modulating gene expression. This study extends our previous work and shows that four VZVsncRNA clustering in and near ORF61 and antisense to the latency-associated transcript of VZV can positively influence productive VZV infection. The ability of multiple exogenous small oligonucleotides targeting VZVsncRNA to inhibit VZV replication strengthens the possibility that they may inform development of novel treatments for painful herpes zoster.

RNA Polymerase III as a Gatekeeper to Prevent Severe VZV Infections.

In most individuals, varicella zoster virus (VZV) causes varicella upon primary infection and zoster during reactivation. However, in a subset of individuals, VZV may cause severe disease, including encephalitis. Host genetics is believed to be the main determinant of exacerbated disease manifestations. Recent studies have demonstrated that defects in the DNA sensor RNA polymerase III (POL III) confer selective increased susceptibility to VZV infection, thus providing fundamental new insight into VZV immunity. Here we describe the roles of POL III in housekeeping and immune surveillance during VZV infection. We present the latest knowledge on the role of POL III in VZV infection and discuss outstanding questions related to the role of POL III in VZV immunity, and how this insight can be translated into clinical medicine.

Increased herpes zoster risk associated with poor HLA-A immediate early 62 protein (IE62) affinity.

Around 30% of individuals will develop herpes zoster (HZ), caused by the varicella zoster virus (VZV), during their life. While several risk factors for HZ, such as immunosuppressive therapy, are well known, the genetic and molecular components that determine the risk of otherwise healthy individuals to develop HZ are still poorly understood. We created a computational model for the Human Leukocyte Antigen (HLA-A, -B, and -C) presentation capacity of peptides derived from the VZV Immediate Early 62 (IE62) protein. This model could then be applied to a HZ cohort with known HLA molecules. We found that HLA-A molecules with poor VZV IE62 presentation capabilities were more common in a cohort of 50 individuals with a history of HZ compared to a nationwide control group, which equated to a HZ risk increase of 60%. This tendency was most pronounced for cases of HZ at a young age, where other risk factors are less prevalent. These findings provide new molecular insights into the development of HZ and reveal a genetic predisposition in those individuals most at risk to develop HZ.

Transient Receptor Potential Vanilloid-1 in Epidermal Keratinocytes May Contribute to Acute Pain in Herpes Zoster.

The role of transient receptor potential vanilloid-1 (TRPV1) in the initiation of neurogenic inflammation and transduction of pain is well established. In this study 33 patients with herpes zoster (HZ) were recruited from a single centre and underwent a questionnaire interview at their first visit. Punch biopsies from the HZ lesions and the contralateral unaffected skin were performed to localize and quantify the expression of TRPV1. Immunofluorescent staining for TRPV1 was most prominent in the epidermal keratinocytes. Both TRPV1 mRNA and protein levels were significantly higher in the HZ epidermis than in control epidermis (relative ratio 1.62 ± 0.27, p = 0.033 and 2.55 ± 0.51, p = 0.005, respectively). Protein TRPV1 ratio (HZ lesion/control) correlated with the degree of pain (measured on a visual analogue scale; VAS) (p = 0.017) and was significantly lower in patients who had taken either HZ medication or painkillers prior to their visit. These results suggest that non-neuronal TRPV1 may contribute to acute pain in herpes zoster.

Activation of H2AX and ATM in varicella-zoster virus (VZV)-infected cells is associated with expression of specific VZV genes.

Mammalian cells activate DNA damage response pathways in response to virus infections. Activation of these pathways can enhance replication of many viruses, including herpesviruses. Activation of cellular ATM results in phosphorylation of H2AX and recruits proteins to sites of DNA damage. We found that varicella-zoster (VZV) infected cells had elevated levels of phosphorylated H2AX and phosphorylated ATM and that these levels increased in cells infected with VZV deleted for ORF61 or ORF63, but not deleted for ORF67. Expression of VZV ORF61, ORF62, or ORF63 alone did not result in phosphorylation of H2AX. While BGLF4, the Epstein-Barr virus homolog of VZV ORF47 protein kinase, phosphorylates H2AX and ATM, neither VZV ORF47 nor ORF66 protein kinase phosphorylated H2AX or ATM. Cells lacking ATM had no reduction in VZV replication. Thus, VZV induces phosphorylation of H2AX and ATM and this effect is associated with the presence of specific VZV genes in virus-infected cells.

Cellular transcription factor YY1 mediates the varicella-zoster virus (VZV) IE62 transcriptional activation.

Several cellular transcription factors have been shown to be involved in IE62-mediated activation. The YY1 cellular transcription factor has activating and repressive effects on gene transcription. Analysis of the VZV genome revealed 19 postulated YY1 binding sites located within putative promoters of 16 VZV genes. Electrophoretic mobility shift assays (EMSA) confirmed the binding of YY1 to ORF10, ORF28/29 and gI promoters and the mutation of these binding sites inhibited YY1 binding and the promoter activation by IE62 alone or following VZV infection. Mutation of the ORF28/29 YY1 site in the VZV genome displayed insignificant influence on virus growth in melanoma cells; but it inhibited the virus replication significantly at day 5 and 6 post infection in HELF cells. This work suggests a novel role for the cellular factor YY1 in VZV replication through the mediation of IE62 activation of viral gene expression.

[Frequency of the occurrence of spliced variants of the messenger RNA DR3/LARD in herpesviral infection].

Analysis of frequency of the occurrence of membrane and soluble forms of the mRNA DR3/LARD in blood in herpesviral infection of various etiology was studied. Four forms of the mRNA DR3/LARD were detected with various frequencies in blood cells of healthy volunteers. Patients with herpesviral infection of various etiology were studied using RT-PCR. Two forms encoded membrane molecules (mRNA LARD 1a, mRNA DR3beta) and two other forms accorded soluble forms of receptor (mRNA LARD 3, mRNA soluble DR3beta). It was revealed that the frequency of the occurrence of mRNA soluble DR3beta form decreased in patients with the varicella zoster virus (VZV) infection in comparison with healthy volunteers. However, the patients with the Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infection did not display significant change in occurrence of mRNA soluble DR3beta form. As a whole, changes in frequency of occurrence of spliced variants of mRNA DR3/LARD are directed toward modulation of apoptosis and restraint antiviral immune response.

Allotype analysis to distinguish the origin of varicella-zoster virus immunoglobulin G after allogeneic stem cell transplantation.

Varicella-zoster virus (VZV) reactivation is a frequent complication after allogeneic hematopoietic stem cell transplantation (HSCT). Although previous studies have revealed that cellular immunity is important for suppressing reactivation, the role of humoral immunity against VZV has been poorly evaluated. We analyzed inherited polymorphisms in the immunoglobulin G (IgG) heavy chain constant regions of 50 HSCT recipient-donor pairs to distinguish donor-derived and recipient-derived antibodies. Twelve pairs were informative regarding the origin of IgG, since either the donors (n = 3) or recipients (n = 9) were homozygous null for the IgG1m(f) allotype. In these 9 homozygous-null recipients, allotype-specific IgG against VZV were measured by enzyme-linked immunosorbent assay and compared with measles-IgG. All 9 homozygous-null recipients were monitored for more than 1 year after HSCT, with (n = 4, localized zoster) or without (n = 5) clinical VZV disease. In 3 patients with VZV disease, donor-derived IgG against VZV was elevated between 500 to 700 days after HSCT after the episode of VZV disease. In 1 patient who suffered from VZV disease just before HSCT, donor-derived VZV IgG was elevated within 3 months after HSCT. On the other hand, 2 patients who received reduced-intensity conditioning (RIC) transplantation from an IgG1m(f) null donor maintained recipient-derived IgG against VZV for more than 1 year, whereas it was decreased within 3 months in 1 recipient who received conventional conditioning. In conclusion, the production of anti-VZV IgG by recipient plasma cells persists long after RIC. In patients without symptomatic VZV reactivation, donor-derived anti-VZV IgG did not reach titers comparable to those measured in healthy virus carriers.

Varicella-zoster viruses associated with post-herpetic neuralgia induce sodium current density increases in the ND7-23 Nav-1.8 neuroblastoma cell line.

Post-herpetic neuralgia (PHN) is the most significant complication of herpes zoster caused by reactivation of latent Varicella-Zoster virus (VZV). We undertook a heterologous infection in vitro study to determine whether PHN-associated VZV isolates induce changes in sodium ion channel currents known to be associated with neuropathic pain. Twenty VZV isolates were studied blind from 11 PHN and 9 non-PHN subjects. Viruses were propagated in the MeWo cell line from which cell-free virus was harvested and applied to the ND7/23-Nav1.8 rat DRG x mouse neuroblastoma hybrid cell line which showed constitutive expression of the exogenous Nav 1.8, and endogenous expression of Nav 1.6 and Nav 1.7 genes all encoding sodium ion channels the dysregulation of which is associated with a range of neuropathic pain syndromes. After 72 hrs all three classes of VZV gene transcripts were detected in the absence of infectious virus. Single cell sodium ion channel recording was performed after 72 hr by voltage-clamping. PHN-associated VZV significantly increased sodium current amplitude in the cell line when compared with non-PHN VZV, wild-type (Dumas) or vaccine VZV strains ((POka, Merck and GSK). These sodium current increases were unaffected by acyclovir pre-treatment but were abolished by exposure to Tetrodotoxin (TTX) which blocks the TTX-sensitive fast Nav 1.6 and Nav 1.7 channels but not the TTX-resistant slow Nav 1.8 channel. PHN-associated VZV sodium current increases were therefore mediated in part by the Nav 1.6 and Nav 1.7 sodium ion channels. An additional observation was a modest increase in message levels of both Nav1.6 and Nav1.7 mRNA but not Nav 1.8 in PHN virally infected cells.

Varicella-zoster virus inhibition of the NF-κB pathway during infection of human dendritic cells: role for open reading frame 61 as a modulator of NF-κB activity.

Dendritic cells (DC) are antigen-presenting cells essential for initiating primary immune responses and therefore an ideal target for viral immune evasion. Varicella-zoster virus (VZV) can productively infect immature human DCs and impair their function as immune effectors by inhibiting their maturation, as evidenced by the expression modulation of functionally important cell surface immune molecules CD80, CD86, CD83, and major histocompatibility complex I. The NF-κB pathway largely regulates the expression of these immune molecules, and therefore we sought to determine whether VZV infection of DCs modulates the NF-κB pathway. Nuclear localization of NF-κB p50 and p65 indicates pathway activation; however, immunofluorescence studies revealed cytoplasmic retention of these NF-κB subunits in VZV-infected DCs. Western blotting revealed phosphorylation of the inhibitor of κBα (IκBα) in VZV-infected DCs, indicating that the pathway is active at this point. We conclude that VZV infection of DC inhibits the NF-κB pathway following protein phosphorylation but before the translocation of NF-κB subunits into the nucleus. An NF-κB reporter assay identified VZV open reading frame 61 (ORF61) as an inhibitor of tumor necrosis factor alpha-induced NF-κB reporter activity. Mutational analysis of ORF61 identified the E3 ubiquitin ligase domain as a region required for NF-κB pathway inhibition. In summary, we provide evidence that VZV inhibits the NF-κB signaling pathway in human DCs and that the E3 ubiquitin ligase domain of ORF61 is required to modulate this pathway. Thus, this work identifies a mechanism by which VZV modulates host immune function.

Human sensory neurons derived from induced pluripotent stem cells support varicella-zoster virus infection.

After primary infection, varicella-zoster virus (VZV) establishes latency in neurons of the dorsal root and trigeminal ganglia. Many questions concerning the mechanism of VZV pathogenesis remain unanswered, due in part to the strict host tropism and inconsistent availability of human tissue obtained from autopsies and abortions. The recent development of induced pluripotent stem (iPS) cells provides great potential for the study of many diseases. We previously generated human iPS cells from skin fibroblasts by introducing four reprogramming genes with non-integrating adenovirus. In this study, we developed a novel protocol to generate sensory neurons from iPS cells. Human iPS cells were exposed to small molecule inhibitors for 10 days, which efficiently converted pluripotent cells into neural progenitor cells (NPCs). The NPCs were then exposed for two weeks to growth factors required for their conversion to sensory neurons. The iPS cell-derived sensory neurons were characterized by immunocytochemistry, flow cytometry, RT-qPCR, and electrophysiology. After differentiation, approximately 80% of the total cell population expressed the neuron-specific protein, ßIII-tubulin. Importantly, 15% of the total cell population co-expressed the markers Brn3a and peripherin, indicating that these cells are sensory neurons. These sensory neurons could be infected by both VZV and herpes simplex virus (HSV), a related alphaherpesvirus. Since limited neuronal populations are capable of supporting the entire VZV and HSV life cycles, our iPS-derived sensory neuron model may prove useful for studying alphaherpesvirus latency and reactivation.

Varicella-zoster virus infection triggers formation of an interleukin-1ß (IL-1ß)-processing inflammasome complex.

Innate cellular immunity is the immediate host response against pathogens, and activation of innate immunity also modulates the induction of adaptive immunity. The nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs) are a family of intracellular receptors that recognize conserved patterns associated with intracellular pathogens, but information about their role in the host defense against DNA viruses is limited. Here we report that varicella-zoster virus (VZV), an alphaherpesvirus that is the causative agent of varicella and herpes zoster, induces formation of the NLRP3 inflammasome and the associated processing of the proinflammatory cytokine IL-1ß by activated caspase-1 in infected cells. NLRP3 inflammasome formation was induced in VZV-infected human THP-1 cells, which are a transformed monocyte cell line, primary lung fibroblasts, and melanoma cells. Absent in melanoma gene-2 (AIM2) is an interferon-inducible protein that can form an alternative inflammasome complex with caspase-1 in virus-infected cells. Experiments in VZV-infected melanoma cells showed that NLRP3 protein recruits the adaptor protein ASC and caspase-1 to form an NLRP3 inflammasome complex independent of AIM2 protein and in the absence of free radical reactive oxygen species release. NLRP3 was also expressed extensively in infected skin xenografts in the severe combined immunodeficiency mouse model of VZV pathogenesis in vivo. We conclude that NLRP3 inflammasome formation is an innate cellular response to infection with this common pathogenic human herpesvirus.

Serology and serum DNA detection in shingles.

AIM: To investigate the sensitivity of various laboratory approaches in the diagnosis of herpes zoster from patient serum. METHODS: Paired sera from 53 consecutive adult patients with acute herpes zoster were tested for the presence of varicella-zoster virus (VZV) antibodies. All acute sera were tested subsequently by real-time polymerase chain reaction (PCR) for the presence of VZV DNA. In addition, convalescent sera of patients who tested initially positive for VZV DNA underwent PCR analysis. RESULTS: VZV IgM antibodies were found by enzyme immunoassay (EIA) in 5 acute (9%) and 20 convalescent (38%) zoster sera. VZV DNA was detected by PCR in 21 (40%) acute zoster sera and was no longer detectable in the convalescent samples. A seroconversion or a fourfold or greater titre increase was found by complement fixation (CF) test in 41 (77%), by IgG indirect fluorescent antibody assay (IgG IFA) in 43 (81%) and by CF and IgG IFA combined in 45 of 53 (85%) paired zoster sera. The combination of all serological methods detected 51 (96%) and PCR combined with serology identified 52 (98%) of 53 patients. CONCLUSIONS: Optimal laboratory sensitivity in the diagnosis of herpes zoster from serum can be achieved by the combination of PCR and serology of paired serum samples. Serological methods alone are of limited value for early diagnosis of zoster when therapy can be initiated, because CF and IgG IFA need convalescent serum and IgM test sensitivity is insufficient. Early diagnosis of VZV reactivation is possible from serum by PCR in the first days of illness and test sensitivity needs further improvement. The findings highlight the need for future studies into the usefulness of PCR and serology in atypical cases of VZV reactivation.

[Viral infection of herpes simplex, Epstein-Barr, varicela zoster, human papilloma, cytomegalovirus, or adenovirus are not related to sinonasal adenocarcinomas]. / Las infecciones por virus herpes simplex, Epstein-Barr, varicela zoster, papiloma humano, citomegalovirus o adenovirus no tienen relación con los adenocarcinomas nasosinusales.

OBJECTIVE: Several types of virus have been implicated in the development of head and neck tumors. However, until now sinonasal adenocarcinomas (ACN) have not been studied. The aim of this study is to screen a series of ACN for the presence of a number of viruses known to play a role in cancer. MATERIAL AND METHOD: Viral DNA sequences of herpes simplex virus, Epstein-Barr, varicela zoster, human papilloma, cytomegalovirus, and adenovirus were analysed by PCR in 37 primary ACN. RESULTS: Three tumors (8.1%) were positive for Epstein-Barr virus and 1 case (2.7%) for cytomegalovirus. CONCLUSIONS: Viral infections do not seem to play a role in the etiology of ACN.

Clinical and genetic risk factors of herpes zoster in patients with systemic lupus erythematosus.

OBJECTIVE: The aim of this study was to determine the clinical and genetic risk factors that influence herpes zoster occurrence in patients with systemic lupus erythematosus (SLE). METHODS: Three hundred three SLE patients meeting the American College of Rheumatology criteria were enrolled in this study. Herpes zoster was diagnosed when classic grouped vesicles were noted. Medical records were reviewed retrospectively to collect clinical information. For Fc gamma receptor IIa (Fc gamma RIIa) and Fc gamma RIIIa genotyping, polymerase chain reaction (PCR) using allele-specific primers was performed. The PCR sequence-specific oligonucleotide probe method was utilized in human HLA-DRB1 genotyping. RESULTS: Forty-two cases (13.9%) of zoster occurred among 303 SLE patients. The incidence of zoster in patients with SLE was 32.5/1,000 patients per year. Patients who developed zoster had higher rates of lupus nephritis (P = 0.018) and positive anti-Sm antibody (P = 0.019). However, Fc gamma RIIa and Fc gamma RIIIa polymorphism and the HLA-DRB1 genotype did not influence herpes zoster occurrence. CONCLUSION: Systemic lupus erythematosus patients with lupus nephritis or anti-Sm antibody are at higher risk of herpes zoster. Fc gamma RIIa (H/R131), Fc gamma RIIIa (F/V176), and HLA-DRB1 genetic polymorphisms did not influence the occurrence of herpes zoster in these patients.

Association of HLA-A*3303-B*4403-DRB1*1302 haplotype, but not of TNFA promoter and NKp30 polymorphism, with postherpetic neuralgia (PHN) in the Japanese population.

Herpes zoster is a common disease caused by reactivation of the varicella zoster virus (VZV). In a small number of herpes zoster patients, pain persists beyond 4 weeks or more after healing of vesicular eruptions; this condition is termed postherpetic neuralgia (PHN). Positive associations of human histocompatibility leukocyte antigens (HLA) class I antigens, A33 and B44, with PHN in the Japanese population have been reported. Our hypothesis is that susceptibility genes to PHN might exist in the HLA region and the study objective is to further examine possible associations of genes in HLA class I, II and III regions, HLA-A, -B, -DRB1, tumor necrosis factor alpha (TNFA) promoter, and a natural killer cell activating receptor, NKp30 polymorphisms with PHN. Although TNFA or NKp30 in the class III region had been considered as a candidate locus, we found no associations of TNFA promoter or NKp30 polymorphisms with PHN in this study. We demonstrated that HLA-A*3303, -B*4403 and -DRB1*1302 alleles were significantly associated with PHN (P = 0.0007 for A*3303, P = 0.001 for B*4403 and P = 0.001 for DRB1*1302). The frequency of the HLA-A*3303-B*4403-DRB1*1302 haplotype was also significantly higher in the PHN patients than in the healthy controls (P = 0.0039). Our results suggest that this haplotype might be related to the pathogenesis of PHN.

Infectious simian varicella virus expressing the green fluorescent protein.

Clinical, pathologic, immunologic and virologic features of simian varicella virus (SVV) infection in primates closely resemble varicella-zoster virus (VZV) infection in humans. Such similarities provide a rationale to analyze SVV infection in primates as a model of varicella pathogenesis and latency. Thus, we constructed an SVV-expressing green fluorescent protein (SVV-GFP) by inserting the GFP gene into the unique short segment of the virus genome by homologous recombination. Analysis of recombinant viral DNA and the expressed proteins of plaque-purified SVV-GFP confirmed the location of the GFP insert and that the recombinant SVV expressed the 27 kDa GFP. Infection of monkey kidney cells in tissue culture with SVV-GFP revealed bright green fluorescence associated with the characteristic focal cytopathic effect produced by SVV infection. Microscopic examination of lung from a 3-month-old African green monkey 10 days after infection with SVV-GFP revealed bright green fluorescence in areas of acute necrotizing pneumonitis. SVV-GFP allows ready identification of cells infected with SVV both in vitro and in vivo, and will be useful for further analysis of varicella pathogenesis and latency in experimentally infected animals--studies not possible in humans.