Simian Varicella Virus Expresses a Latency-Associated Transcript That Is Antisense to Open Reading Frame 61 (ICP0) mRNA in Neural Ganglia of Latently Infected Monkeys

dVaricella zoster virus (VZV) is a neurotropic alphaherpesvirus that causes chickenpox during primary infection and establishes latency in sensory ganglia. Infection of rhesus macaques (RM) with the homologous simian varicella virus (SVV) recapitulates hallmarks of VZV infection. We have shown that an antisense transcript of SVV open reading frame 61 (ORF61), a viral transactivator, was detected most frequently in latently infected RM sensory ganglia. In this study, we compared disease progression, viral replication, immune response, and the establishment of latency following intrabronchial infection with a recombinant SVV lacking ORF61 (SVV⌬ORF61) to those following infection with wild-type (WT) SVV. Varicella severity and viral latency within sensory ganglia were comparable in RMs infected with SVV⌬ORF61 and WT SVV. In contrast, viral loads, B and T cell responses, and plasma inflammatory cytokine levels were decreased in RMs infected with SVV⌬ORF61. To investigate the mechanisms underlying the reduced adaptive immune response, we compared acute SVV gene expression, frequency and proliferation of dendritic cell (DC) subsets, and the expression of innate antiviral genes in bronchoalveolar lavage (BAL) samples. The abundance of SVV transcripts in all kinetic classes was significantly decreased in RMs infected with SVV⌬ORF61. In addition, we detected a higher frequency and proliferation of plasmacytoid dendritic cells in BAL fluid at 3 days postinfection in RMs infected with SVV⌬ORF61, which was accompanied by a slight increase in type I interferon gene expression. Taken together, our data suggest that ORF61 plays an important role in orchestrating viral gene expression in vivo and interferes with the host antiviral interferon response. V aricella zoster virus (VZV) is a neurotropic human alphaherpesvirus that causes chickenpox (varicella) during primary infection. VZV establishes a life-long latent infection in sensory ganglia, including the trigeminal and dorsal root ganglia. Reactivation of VZV leads to herpes zoster (HZ; shingles), which is estimated to affect 1 million individuals each year in the United States and can result in significant morbidity and occasionally mortality in aged and immunocompromised individuals (1-4). Reactivation of VZV is generally believed to be due to a decline in T cell immunity (5-10); however, the viral genes that control the switch between latent and lytic replication remain unknown. This is due in part to the fact that VZV is strictly a human pathogen, and animal models of VZV infection recapitulate only certain aspects of pathogenesis. We have previously shown that rhesus macaques (RMs) infected with simian varicella virus (SVV) display the hallmarks of VZV infection in humans, including generalized varicella, development of cellular and humoral immunity, and establishment of latency (11).Utilizing this model, we previously found that SVV open reading frame 61 (ORF61) was the most prevalent transcript detected during latency in sensory ganglia (12). Interestingly, SVV ORF61 ...

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confidence: 63%

Attenuation of the Adaptive Immune Response in Rhesus Macaques Infected with Simian Varicella Virus Lacking Open Reading Frame 61

Meyer

Kerns

Haberthur

et al. 2013

“…Notably, T-cell numbers and clusters were not increased in ganglia corresponding to the site of zoster rash (Table 1). SVV open reading frame 61 (ORF61) antisense transcripts are abundant in latently infected ganglia of rhesus macaques (10,11). Thus, we analyzed consecutive ganglionic sections after reactivation by in situ hybridization (ISH) for SVV ORF61 antisense RNA and by immunohistochemistry (IHC) for CD3 expression and SVV antigen to determine if SVV infection might mediate T-cell infiltration of ganglia.…”

Section: Fig 2 Increased Number Of Ganglion-infiltrating T Cells and mentioning

confidence: 99%

T-Cell Infiltration Correlates with CXCL10 Expression in Ganglia of Cynomolgus Macaques with Reactivated Simian Varicella Virus

Ouwendijk

Abendroth

Traina‐Dorge

et al. 2013

Self Cite

Ganglia of monkeys with reactivated simian varicella virus (SVV) contained more CD8 than CD4 T cells around neurons. The abundance of CD8 T cells was greater less than 2 months after reactivation than that at later times and correlated with that of CXCL10 RNA but not with those of SVV protein or open reading frame 61 (ORF61) antisense RNA. CXCL10 RNA colocalized with T-cell clusters. After SVV reactivation, transient T-cell infiltration, possibly mediated by CXCL10, parallels varicella zoster virus (VZV) reactivation in humans. Varicella zoster virus (VZV) causes varicella (chickenpox) and becomes latent in ganglia, producing zoster (shingles) upon reactivation. Because VZV infects only humans, studies of virus latency and reactivation have been restricted to autopsy tissues. Analyses of ganglia obtained after death from individuals with recent zoster revealed lymphocytic infiltration (1, 2), possibly mediated by antigenic stimuli or chemokines, including CXCL10 (3). VZV-specific T cells have not been identified in human ganglia latently infected with VZV (4, 5). Simian varicella virus (SVV) infection in monkeys closely resembles VZV infection in humans (6). Earlier, we demonstrated reactivation of latent SVV in immunosuppressed monkeys (7). Herein, we extended those studies by examining ganglia containing reactivated SVV for infiltrating T cells. Four cynomolgus macaques (GP02, -04, -06, and -07) were naturally infected with SVV (7). Ten to 14 days later, all monkeys developed varicella ( Fig. 1). At 4 months postinfection, monkeys were immunosuppressed with tacrolimus, resulting in a 34% reduction in mean white blood cell counts at 6 weeks posttreatment (7). Monkeys GP02, -06, and -07 developed zoster at 23, 3, and 10 days, respectively, after starting tacrolimus. Monkeys were euthanized at monthly intervals post-tacrolimus treatment (Fig. 1). Detection of SVV glycoproteins in lungs and multiple ganglia in monkey GP04, which did not develop skin rash, confirmed subclinical reactivation (7).Immunohistochemical analysis of consecutive ganglion tissue sections from these monkeys and from an uninfected control monkey (CTRL) for CD3, CD4 and CD8 expression showed that SVV reactivation was associated with T-cell infiltration, mostly CD8 T cells, in ganglia along the entire neuraxis (Fig. 2). T cells were dispersed throughout ganglia. T-cell clusters, of both CD4 and CD8 T cells, were occasionally detected adjacent to neurons ( Fig. 2A). Rare granzyme B ϩ (grB) cells, not restricted to T-cell clusters, were observed in ganglia from all monkeys ( Fig. 2A), suggesting that ganglion-infiltrating T cells did not encounter their cognate antigen (8). Ganglion-infiltrating CD8 T cells in zoster patients are also predominantly grB negative (9).We analyzed 11 to 19 ganglia from each monkey to determine the number of T cells per neuron. The number of ganglionic neurons counted in sections from each anatomical level of the neuraxis ranged from 657 to 3,991 (Table 1). Ganglia obtained from monkey GP02, euthanized at 4 days post-...

“…SVV ORF 61 is a viral transactivator that also expresses an antisense transcript. ORF 61 sense transcripts are detected most often during acute infection, whereas antisense transcripts are more abundant during latent infection (40). ORF 61 was detected in 10 of 16 ganglia from control RMs, 8 of 8 ganglia from aged RMs, 8 of 12 ganglia from CD4-depleted RMs, 2 of 14 ganglia from CD8-depleted RMs, and 2 of 13 ganglia from CD20-depleted RMs (Table 3).…”

Section: Discussionmentioning

confidence: 99%

“…Viral latency is generally characterized by a quiescent state with limited gene expression; for example, during herpes simplex virus (HSV) latency, only the latency-associated transcripts (LATs) are abundantly expressed (1). However, VZV latency can be associated with the transcription of multiple genes, including open reading frames (ORFs) 4,11,18,21,29,40,41,43,57,62,63,66, and 68 (2)(3)(4)(5)(6)(7)(8)(9). We recently examined the SVV latent transcriptome from juvenile rhesus macaques (RMs) and found that SVV latency is characterized by a restricted gene expression profile (10).…”

Section: S Imian Varicella Virus (Svv) and Varicella-zoster Virus (Vzv)mentioning

confidence: 99%

Age and Immune Status of Rhesus Macaques Impact Simian Varicella Virus Gene Expression in Sensory Ganglia

Meyer

Dewane²,

Kerns³

et al. 2013

S imian varicella virus (SVV) and varicella-zoster virus (VZV)are neurotropic alphaherpesviruses that establish latency within the sensory ganglia during primary infection. Viral latency is generally characterized by a quiescent state with limited gene expression; for example, during herpes simplex virus (HSV) latency, only the latency-associated transcripts (LATs) are abundantly expressed (1). However, VZV latency can be associated with the transcription of multiple genes, including open reading frames (ORFs) 4, 11, 18, 21, 29, 40, 41, 43, 57, 62, 63, 66, and 68 (2-9). We recently examined the SVV latent transcriptome from juvenile rhesus macaques (RMs) and found that SVV latency is characterized by a restricted gene expression profile (10). SVV ORF 61 was the most prevalent transcript detected during latent infection, present in at least one sensory ganglion in all RMs tested and in 10 of 16 sensory ganglia total. We also detected SVV ORFs A, B, 4, 10, 55, 63, 64, 65, 66, 67, and 68, although less frequently, in 1 to 4 of 16 latently infected sensory ganglia from juvenile RMs.Several clinical observations highlight the importance of cellmediated immune responses in controlling VZV infection and reactivation. Specifically, a lack of immunoglobulin production due to agammaglobulinemia does not complicate the outcome of varicella in children (11,12). In contrast, T cell deficiencies, including congenital deficiencies or those induced by HIV infection or immune suppression, lead to severe and disseminated varicella (13-17). Similarly, a higher incidence of herpes zoster (HZ) in aged patients is associated with diminished T cell proliferation to VZV antigens in vitro, while antibody titers remain stable (18). Moreover, HIV patients are more susceptible to HZ when their absolute numbers of CD4 T cells decline to less than 500 cells per microliter (19)(20)(21). Finally, the frequency of VZV reactivation is related to the intensity of immune suppression, with higher incidence in patients receiving combined therapy than in patients receiving chemotherapy or radiotherapy alone (22).We have recently shown that the resolution of acute SVV infection is also dependent on cellular immunity. Specifically, loss of CD4 T cells during acute SVV infection in juvenile RMs resulted in higher peak viral loads, prolonged viremia, and disseminated varicella compared to these parameters in controls (23). CD8-depleted RMs had slightly higher viral loads and more prolonged varicella rash than controls. Lastly, CD20 depletion did not alter the severity of varicella or the kinetics and magnitude of the T cell response. Our data indicate that CD4 T cell immunity is critical in controlling acute SVV infection in RMs and are in agreement with clinical observations during acute VZV infection.To improve HZ-associated morbidity, it is critical to understand the virological and immunological parameters that control latency and reactivation. In the present study, we extend our previous reports (10, 23) and investigate the impact of T cell and B c...