In vivo imaging of murid herpesvirus-4 infection

Milho, Ricardo; Smith, Christopher M.; Marques, Sofia; Alenquer, Marta; May, Janet S.; Gillet, Laurent; Gaspar, Miguel; Efstathiou, Stacey; Simas, J. Pedro; Stevenson, Philip G.

doi:10.1099/vir.0.006569-0

Cited by 73 publications

(151 citation statements)

References 57 publications

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“…7B), suggesting that other B-cell populations express mLANA at those time points. In addition, B cells, macrophages, and dendritic cells are latently infected at other sites, including the blood, lymph nodes, lung, and peritoneal cavity (16,17,39,54,65). Future experiments will be critical to determine whether mLANA is expressed in other major infected cell populations.…”

Section: Discussionmentioning

confidence: 99%

Use of a Virus-Encoded Enzymatic Marker Reveals that a Stable Fraction of Memory B Cells Expresses Latency-Associated Nuclear Antigen throughout Chronic Gammaherpesvirus Infection

Nealy

Coleman

et al. 2010

J Virol

102

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An integral feature of gammaherpesvirus infections is the ability to establish lifelong latency in B cells. During latency, the viral genome is maintained as an extrachomosomal episome, with stable maintenance in dividing cells mediated by the viral proteins Epstein-Barr nuclear antigen 1 (EBNA-1) for Epstein-Barr virus and latencyassociated nuclear antigen (LANA) for Kaposi's sarcoma-associated herpesvirus. It is believed that the expression of episome maintenance proteins is turned off in the predominant long-term latency reservoir of resting memory B cells, suggesting that chronic gammaherpesvirus infection is primarily dormant. However, the kinetics of LANA/ EBNA-1 expression in individual B-cell subsets throughout a course of infection has not been examined. The infection of mice with murine gammaherpesvirus 68 (MHV68, ␥HV68) provides a model to determine the specific cellular and molecular events that occur in vivo during lifelong gammaherpesvirus latency. In work described here, we make use of a heterologously expressed enzymatic marker to define the types of B cells that express the LANA homolog (mLANA) during chronic MHV68 infection. Our data demonstrate that mLANA is expressed in a stable fraction of B cells throughout chronic infection, with a prominent peak at 28 days. The expression of mLANA was detected in naïve follicular B cells, germinal-center B cells, and memory B cells throughout infection, with germinalcenter and memory B cells accounting for more than 80% of the mLANA-expressing cells during the maintenance phase of latency. These findings suggest that the maintenance phase of latency is an active process that involves the ongoing proliferation or reseeding of latently infected memory B cells.Gammaherpesviruses such as Epstein-Barr virus (EBV), Kaposi's sarcoma-associated virus (KSHV, HHV-8), and murine gammaherpesvirus 68 (MHV68, ␥HV68) are associated with lymphoproliferative diseases and a variety of malignancies of both epithelial and lymphoid origin. The strict species specificity exhibited by gammaherpesviruses has limited research on the human viruses primarily to in vitro studies. MHV68 is genetically colinear to the human gammaherpesviruses and exhibits many similar pathogenic features (54, 62). MHV68 is a natural pathogen of rodents (6, 9, 44), making the inoculation of mice with MHV68 a useful small-animal model to study gammaherpesvirus infection in vivo.A hallmark of gammaherpesvirus infections is the establishment of lifelong latency in B cells. During latency, the viral genome is maintained as an extrachromosomal episome, viral gene expression is highly restricted, and no new progeny virions are generated. The stable maintenance of the episome in dividing cells requires regulated plasmid DNA replication and the efficient partitioning of replicated genomes to daughter cells. These processes are mediated by critical episome maintenance protein Epstein-Barr nuclear antigen 1 (EBNA-1) for EBV and latency-associated nuclear antigen (LANA) for KSHV. EBNA-1 and LANA facilitate the re...

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Section: Discussionmentioning

confidence: 99%

Use of a Virus-Encoded Enzymatic Marker Reveals that a Stable Fraction of Memory B Cells Expresses Latency-Associated Nuclear Antigen throughout Chronic Gammaherpesvirus Infection

Nealy

Coleman

et al. 2010

J Virol

102

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“…In vivo imaging studies can be performed only on sufficiently smallanimal models to ensure effective transmission and detection of light (20), which renders rabbits difficult to use with this system. However, bioluminescent signals can effectively be detected from explanted organs of euthanized animals (28). In order to detect AlHV-1 infection ex vivo during WD-MCF, we used the recent BAC clone of the infectious and pathogenic C500 strain of AlHV-1 (13) and produced a recombinant strain expressing LUC as a reporter protein.…”

Section: Discussionmentioning

confidence: 99%

Ex Vivo Bioluminescence Detection of Alcelaphine Herpesvirus 1 Infection during Malignant Catarrhal Fever

Dewals

Myster

Palmeira

et al. 2011

J Virol

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Alcelaphine herpesvirus 1 (AlHV-1), carried by wildebeest asymptomatically, causes malignant catarrhal fever (WD-MCF) when cross-species transmitted to a variety of susceptible species of the Artiodactyla order. Experimentally, WD-MCF can be reproduced in rabbits. WD-MCF is described as a combination of lymphoproliferation and degenerative lesions in virtually all organs and is caused by unknown mechanisms. Recently, we demonstrated that WD-MCF is associated with the proliferation of CD8 ؉ cells supporting a latent type of infection in lymphoid tissues. Here, we investigated the macroscopic distribution of AlHV-1 infection using ex vivo bioluminescence imaging in rabbit to determine whether it correlates with the distribution of lesions in lymphoid and nonlymphoid organs. To reach that goal, a recombinant AlHV-1 strain was produced by insertion of a luciferase expression cassette (luc) in an intergenic region. In vitro, the reconstituted AlHV-1 luc ؉ strain replicated comparably to the parental strain, and luciferase activity was detected by bioluminescence imaging. In vivo, rabbits infected with the AlHV-1 luc ؉ strain developed WD-MCF comparably to rabbits infected with the parental wild-type strain, with hyperthermia and increases of both CD8 ؉ T cell frequencies and viral genomic charge over time in peripheral blood mononuclear cells and in lymph nodes at time of euthanasia. Bioluminescent imaging revealed that AlHV-1 infection could be detected ex vivo in lymphoid organs but also in lung, liver, and kidney during WD-MCF, demonstrating that AlHV-1 infection is prevalent in tissue lesions. Finally, we show that the infiltrating mononuclear leukocytes in nonlymphoid organs are mainly CD8 ؉ T cells and that latency is predominant during WD-MCF.

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“…However SCLN infection is asynchronous, making early events hard to capture. This reflects the fact that mucosal penetration requires viral replication: a replicationdeficient mutant (ORF50 2 MHV-GFP; Milho et al, 2009) gave no EGFP + cells in SCLNs (data not shown). Therefore, we also tracked popliteal LN (PLN) infection after MuHV-4 inoculation into footpads (10 5 p.f.u.…”

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confidence: 97%