scholarly journals A Novel Viral Transcript with Homology to Human Interleukin-10 Is Expressed during Latent Human Cytomegalovirus Infection

2004 ◽  
Vol 78 (3) ◽  
pp. 1440-1447 ◽  
Author(s):  
Christina Jenkins ◽  
Allison Abendroth ◽  
Barry Slobedman
Keyword(s):  
Human Cytomegalovirus ◽  
Mononuclear Cells ◽  
Latent Infection ◽  
Interleukin 10 ◽  
Productive Infection ◽  
Viral Gene ◽  
Immune Recognition ◽  
Viral Transcript ◽  
Latently Infected ◽  
Latent Phase

ABSTRACT Human cytomegalovirus (CMV) establishes latent infections in hematopoietic cells such as granulocyte-macrophage progenitors (GM-Ps). During latency the virus is sequestered in a nonreplicating state, although limited transcriptional activity has been previously reported. In this study we sought to further examine viral gene expression during the latent phase of infection. Using an experimental model of latency, primary human GM-Ps were latently infected with CMV strain Toledo and extracted RNA subjected to reverse transcription-PCR by using CMV gene-specific primers. Using this approach, we detected transcription from the UL111.5A region of the viral genome. This transcription was also detected in GM-Ps latently infected with AD169 and Towne strains, indicating that expression was CMV strain independent. Significantly, we detected UL111.5A-region transcripts in mononuclear cells from healthy bone marrow and mobilized peripheral blood allograft donors, demonstrating expression during natural latent infection. Mapping experiments with RNA extracted from latently infected GM-Ps revealed the expression of a novel UL111.5A region transcript with a splicing pattern that differed from that reported during productive infection of permissive cells. This UL111.5A region transcript expressed during latent infection is predicted to encode a 139-amino-acid protein with homology to the potent immunosuppressor interleukin-10 (IL-10) and to the viral IL-10 homolog that is expressed during productive CMV infection. Expression of a latency-associated cmvIL-10 may confer upon the virus an ability to avoid immune recognition and clearance during the latent phase of infection.

scholarly journals Immunohistochemical Analysis of Primary Sensory Neurons Latently Infected with Herpes Simplex Virus Type 1

2000 ◽  
Vol 74 (1) ◽  
pp. 209-217 ◽  
Author(s):  
L. Yang ◽  
C. C. Voytek ◽  
T. P. Margolis
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Sensory Neurons ◽  
Latent Infection ◽  
Productive Infection ◽  
Viral Gene ◽  
Primary Sensory Neurons ◽  
Neuronal Populations ◽  
Latently Infected ◽  
Simplex Virus

ABSTRACT We characterized the populations of primary sensory neurons that become latently infected with herpes simplex virus (HSV) following peripheral inoculation. Twenty-one days after ocular inoculation with HSV strain KOS, 81% of latency-associated transcript (LAT)-positive trigeminal ganglion (TG) neurons coexpressed SSEA3, 71% coexpressed TrkA (the high-affinity nerve growth factor receptor), and 68% coexpressed antigen recognized by monoclonal antibody (MAb) A5; less than 5% coexpressed antigen recognized by MAb KH10. The distribution of LAT-positive, latently infected TG neurons contrasted sharply with (i) the overall distribution of neuronal phenotypes in latently infected TG and (ii) the neuronal distribution of viral antigen in productively infected TG. Similar results were obtained following ocular and footpad inoculation with KOS/62, a LAT deletion mutant in which the LAT promoter is used to drive expression of theEscherichia coli lacZ gene. Thus, although all neuronal populations within primary sensory ganglia appear to be capable of supporting a productive infection with HSV, some neuronal phenotypes are more permissive for establishment of a latent infection with LAT expression than others. Furthermore, expression of HSV LAT does not appear to play a role in this process. These findings indicate that there are marked differences in the outcome of HSV infection among the different neuronal populations in the TG and highlight the key role that the host neuron may play in regulating the repertoire of viral gene expression during the establishment of HSV latent infection.

scholarly journals Immunomodulatory Properties of a Viral Homolog of Human Interleukin-10 Expressed by Human Cytomegalovirus during the Latent Phase of Infection

2008 ◽  
Vol 82 (7) ◽  
pp. 3736-3750 ◽  
Author(s):  
C. Jenkins ◽  
W. Garcia ◽  
M. J. Godwin ◽  
J. V. Spencer ◽  
J. Lewis Stern ◽  
...  
Keyword(s):  
Human Cytomegalovirus ◽  
Neutralizing Antibodies ◽  
Latent Infection ◽  
Cell Types ◽  
Interleukin 10 ◽  
Immune Recognition ◽  
Necrosis Factor Alpha ◽  
Mhc Ii ◽  
Immunosuppressive Cytokine ◽  
The Impact

ABSTRACT Human cytomegalovirus (HCMV) establishes a latent infection in hematopoietic cells, from which it can reactivate to cause significant disease in immunocompromised individuals. HCMV expresses a functional homolog of the immunosuppressive cytokine interleukin-10 (termed cmvIL-10), and alternate splicing of the cmvIL-10 transcript results in expression of a latency-associated cmvIL-10 transcript (LAcmvIL-10). To determine whether LAcmvIL-10 encodes immunosuppressive functions, recombinant LAcmvIL-10 protein was generated, and its impact on major histocompatibility complex class II (MHC-II) expression was examined on granulocyte macrophage progenitor cells (GM-Ps) and monocytes. LAcmvIL-10 (and cmvIL-10) downregulated MHC-II on the surfaces of both cell types. This downregulation was associated with a decrease in total MHC-II protein and transcription of components of the MHC-II biosynthesis pathway. Unlike cmvIL-10, LAcmvIL-10 did not trigger phosphorylation of Stat3, and its ability to downregulate MHC-II was not blocked by neutralizing antibodies to the human IL-10 receptor, suggesting that LAcmvIL-10 either does not engage the cellular IL-10 receptor or utilizes it in a different manner from cmvIL-10. The impact of LAcmvIL-10 on dendritic cell (DC) maturation was also assessed. In contrast to cmvIL-10, LAcmvIL-10 did not inhibit the expression of costimulatory molecules CD40, CD80, and CD86 and the maturation marker CD83 on DCs, nor did it inhibit proinflammatory cytokines (IL-1α, IL-1β, IL-6 and tumor necrosis factor alpha). Thus, LAcmvIL-10 retains some, but not all, of the immunosuppressive functions of cmvIL-10. As GM-Ps and monocytes support latent infection, expression of LAcmvIL-10 may enable HCMV to avoid immune recognition and clearance during latency.

scholarly journals Single cell analysis reveals human cytomegalovirus drives latently infected cells towards an anergic-like monocyte state

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Miri Shnayder ◽  
Aharon Nachshon ◽  
Batsheva Rozman ◽  
Biana Bernshtein ◽  
Michael Lavi ◽  
...  
Keyword(s):  
Immune Response ◽  
Single Cell ◽  
Human Cytomegalovirus ◽  
Single Cell Analysis ◽  
Viral Gene Expression ◽  
Viral Gene ◽  
Viral Transcript ◽  
Hematopoietic Stem ◽  
Latently Infected ◽  
Stem And Progenitor Cells

Human cytomegalovirus (HCMV) causes a lifelong infection through establishment of latency. Although reactivation from latency can cause life-threatening disease, our molecular understanding of HCMV latency is incomplete. Here we use single cell RNA-seq analysis to characterize latency in monocytes and hematopoietic stem and progenitor cells (HSPCs). In monocytes, we identify host cell surface markers that enable enrichment of latent cells harboring higher viral transcript levels, which can reactivate more efficiently, and are characterized by reduced intrinsic immune response that is important for viral gene expression. Significantly, in latent HSPCs, viral transcripts could be detected only in monocyte progenitors and were also associated with reduced immune-response. Overall, our work indicates that regardless of the developmental stage in which HCMV infects, HCMV drives hematopoietic cells towards a weaker immune-responsive monocyte state and that this anergic-like state is crucial for the virus ability to express its transcripts and to eventually reactivate.

scholarly journals Human Cytomegalovirus Latency-Associated Protein pORF94 Is Dispensable for Productive and Latent Infection

2000 ◽  
Vol 74 (19) ◽  
pp. 9333-9337 ◽  
Author(s):  
Kirsten Lofgren White ◽  
Barry Slobedman ◽  
Edward S. Mocarski
Keyword(s):  
Human Cytomegalovirus ◽  
Latent Infection ◽  
Cultured Cells ◽  
Wild Type Virus ◽  
Wild Type ◽  
Reading Frame ◽  
Latently Infected ◽  
Infected Cells ◽  
Latent Phase

ABSTRACT Human cytomegalovirus latency in bone marrow-derived myeloid progenitors is characterized by the presence of latency-associated transcripts encoded in the ie1/ie2 region of the viral genome. To assess the role of ORF94 (UL126a), a conserved open reading frame on these transcripts, a recombinant virus (RC2710) unable to express this gene was constructed. This virus replicated at wild-type levels and expressed productive as well as latency-associatedie1/ie2 region transcripts. During latency in granulocyte-macrophage progenitors, RC2710 DNA was detected at levels indistinguishable from wild-type virus, latent-phase transcription was present, and RC2710 reactivated when latently infected cells were cocultured with permissive fibroblasts. These data suggest pORF94 is not required for either productive or latent infection as assayed in cultured cells despite being the only known nuclear latency-associated protein.

scholarly journals The Mouse Cytomegalovirus Immediate-Early 1 Gene Is Not Required for Establishment of Latency or for Reactivation in the Lungs

2009 ◽  
Vol 83 (9) ◽  
pp. 4030-4038 ◽  
Author(s):  
Andreas Busche ◽  
Anja Marquardt ◽  
Andre Bleich ◽  
Peter Ghazal ◽  
Ana Angulo ◽  
...  
Keyword(s):  
Latent Infection ◽  
Acute Infection ◽  
Lytic Replication ◽  
Immediate Early ◽  
Productive Infection ◽  
Viral Gene ◽  
Mouse Cytomegalovirus ◽  
Early Protein ◽  
Latently Infected

ABSTRACT The immediate-early protein IE1 of human and mouse cytomegalovirus (MCMV) is one of the first proteins expressed during the productive infection cycle and upon reactivation from latency. The CMV IE1 proteins have been found to inhibit histone deacetylases, suggesting a role in the epigenetic regulation of viral gene expression. Consequently, the IE1 protein is considered to have a profound effect on reactivation, because small amounts of IE1 may be decisive for the switch to lytic replication. Here we asked if an MCMV Δie1 mutant is able both to establish latency and to reactivate from the lungs of latently infected mice. Since the Δie1 mutant was known to be attenuated during acute infection, we first defined conditions that led to comparable levels of viral genomes during latent infection with mutant and wild-type (wt) MCMV. Viral genome copy numbers dropped considerably at the onset of the latent infection but then remained steady for both viruses even after several months. Reactivation of the Δie1 mutant and of wt MCMV from latency occurred with similar incidences in lung explant cultures at 4, 7, and 12 months postinfection. The increase in the frequency of a subset of MCMV-specific memory T cells, a possible indicator of frequent transcriptional reactivation events during latency, was in a comparable range for both viruses. Recurrence of the Δie1 virus infection in vivo could also be induced by hematoablative treatment of latently infected mice. We conclude that the ie1 gene is not essential for the establishment of latency or for the reactivation of MCMV.

The role of the human cytomegalovirus UL111A gene in down-regulating CD4+ T-cell recognition of latently infected cells: implications for virus elimination during latency

Blood ◽  
2009 ◽  
Vol 114 (19) ◽  
pp. 4128-4137 ◽  
Author(s):  
Allen K. L. Cheung ◽  
David J. Gottlieb ◽  
Bodo Plachter ◽  
Sandra Pepperl-Klindworth ◽  
Selmir Avdic ◽  
...  
Keyword(s):  
T Cell ◽  
Human Cytomegalovirus ◽  
Latent Infection ◽  
Interleukin 10 ◽  
Cd4 T Cell ◽  
Cell Recognition ◽  
T Cell Recognition ◽  
Latently Infected ◽  
Infected Cells

AbstractThe capacity of human cytomegalovirus (HCMV) to establish and maintain a latent infection from which it can later reactivate ensures its widespread distribution in the population, but the mechanisms enabling maintenance of latency in the face of a robust immune system are poorly understood. We examined the role of the HCMV UL111A gene, which encodes homologs of the immunosuppressive cytokine interleukin-10 in the context of latent infection of myeloid progenitor cells. A UL111A deletion virus was able to establish, maintain, and reactivate from experimental latency in a manner comparable with parental virus, but major histocompatibility complex class II levels increased significantly on the surfaces of cells infected with the deletion virus. Importantly, there was an increase in both allogeneic and autologous peripheral blood mononuclear cells and CD4+ T-cell responses to UL111A deletion virus-infected myeloid progenitors, indicating that loss of the capacity to express viral interleukin-10 during latency results in latently infected cells becoming more readily recognizable by a critical arm of the immune response. The detection of a viral gene that suppresses CD4+ T-cell recognition of latently infected cells identifies an immune evasion strategy that probably enhances the capacity of HCMV to persist in a latent state within the human host.

scholarly journals The gammaherpesvirus 68 viral cyclin facilitates reactivation by promoting latent gene expression

2019 ◽  
Author(s):  
Brian F Niemeyer ◽  
Joy E Gibson ◽  
Jennifer N Berger ◽  
Lauren M Oko ◽  
Eva Medina ◽  
...  
Keyword(s):  
Gene Expression ◽  
Critical Role ◽  
Productive Infection ◽  
Viral Gene ◽  
Cellular Distribution ◽  
Viral Cyclin ◽  
Latently Infected ◽  
Infected Cells ◽  
Virally Encoded ◽  
The Impact

AbstractGammaherpesviruses establish life-long infections within their host and have been shown to be the causative agents of devastating malignancies. Chronic infection within the host is mediated through cycles of transcriptionally quiescent stages of latency with periods of reactivation into more active lytic and productive infection. The mechanisms that regulate reactivation from latency remain poorly understood. Previously, we defined a critical role for the viral cyclin in promoting reactivation from latency. Disruption of the viral cyclin had no impact on the frequency of cells containing viral genome during latency, yet it remains unclear whether the viral cyclin influences latently infected cells in a qualitative manner. To define the impact of the viral cyclin on latent gene expression, we utilized a viral cyclin deficient variant expressing a LANA-beta-lactamase fusion protein (LANA::βla), to enumerate both the cellular distribution and frequency of latent gene expression. Disruption of the viral cyclin did not affect the cellular distribution of latently infected cells, but did result in a significant decrease in the frequency of cells that expressed LANA::βla across multiple tissues and in both immunocompetent and immunodeficient hosts. Strikingly, whereas the cyclin-deficient virus had a reactivation defect in bulk culture, sort purified cyclin-deficient LANA::βla expressing cells were fully capable of reactivation. These data emphasize that the γHV68 latent reservoir is comprised of at least two distinct stages of infection characterized by differential latent gene expression, and that a primary function of the viral cyclin is to promote latent gene expression within infected cells in vivo.AUTHOR SUMMARYGammaherpesviruses are ubiquitous viruses with oncogenic potential that establish latency for the life of the host. These viruses can emerge from latency through reactivation, a process that is controlled by the immune system. Control of viral latency and reactivation is thought to be critical to prevent γHV-associated disease. This study focuses on a virally-encoded cyclin that is required for reactivation from latency. By characterizing how the viral cyclin influences latent infection in pure cell populations, we find that the viral cyclin has a vital role in promoting viral gene expression during latency. This work provides new insight into the function of a virally encoded cyclin in promoting reactivation from latency.

scholarly journals Human cytomegalovirus sequences expressed in latently infected individuals promote a latent infection in vitro

Blood ◽  
2007 ◽  
Vol 110 (3) ◽  
pp. 937-945 ◽  
Author(s):  
Felicia Goodrum ◽  
Matthew Reeves ◽  
John Sinclair ◽  
Kevin High ◽  
Thomas Shenk
Keyword(s):  
Human Cytomegalovirus ◽  
Latent Infection ◽  
Open Reading Frames ◽  
Progeny Virus ◽  
Recombinant Viruses ◽  
Human Cd34 ◽  
Cd34 Cells ◽  
Latently Infected ◽  
Low Passage

AbstractLatency enables human cytomegalovirus (HCMV) to persist in the hematopoietic cells of infected individuals indefinitely and prevents clearance of the pathogen. Despite its critical importance to the viral infectious cycle, viral mechanisms that contribute to latency have not been identified. We compared the ability of low-passage clinical and laboratory-adapted strains of HCMV to establish a latent infection in primary human CD34+ cells. The low-passage strains, Toledo and FIX, established an infection with the hallmarks of latency, whereas the laboratory strains, AD169 and Towne, replicated producing progeny virus. We hypothesized that ULb′ region of the genome, which is unique to low-passage strains, may encode a latency-promoting activity. We created and analyzed recombinant viruses lacking segments or individual open reading frames (ORFs) in the ULb′ region. One 5-kb segment, and more specifically the UL138 ORF, was required for HCMV to establish and/or maintain a latent infection in hematopoietic progenitor cells infected in vitro. This is the first functional demonstration of a virus-coded sequence required for HCMV latency. Importantly, UL138 RNA was expressed in CD34+ cells and monocytes from HCMV-seropositive, healthy individuals. UL138 might be a target for antivirals against latent virus.

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