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Epstein-Barr virus IL-10 gene expression by a recombinant murine gammaherpesvirus in vivo enhances acute pathogenicity but does not affect latency or reactivation.

Lindquester GJ, Greer KA, Stewart JP, Sample JT - Herpesviridae (2014)

Bottom Line: Many viral genes affect cytokine function within infected hosts, with interleukin 10 (IL-10) as a commonly targeted mediator.Recombinant murine gammaherpesvirus expressing EBV vIL-10 rose to significantly higher titers in lungs and promoted an increase in spleen cell number in infected mice in comparison to MHV strains lacking the vIL-10 gene.Given that EBV and MHV wild-type strains contain other genes that induce cIL-10 expression in latency (e.g. LMP-1 and M2, respectively), vIL-10 may have evolved to serve the specific role in acute infection of enlarging the permissive host cell population, perhaps to facilitate initial survival and dissemination of viral-infected cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biology, Rhodes College, Memphis, TN 38112, USA.

ABSTRACT

Background: Many viral genes affect cytokine function within infected hosts, with interleukin 10 (IL-10) as a commonly targeted mediator. Epstein-Barr virus (EBV) encodes an IL-10 homologue (vIL-10) expressed during productive (lytic) infection and induces expression of cellular IL-10 (cIL-10) during latency. This study explored the role of vIL-10 in a murine gammaherpesvirus (MHV) model of viral infection.

Methods: The EBV vIL-10 gene was inserted into MHV-76, a strain which lacks the ability to induce cIL-10, by recombination in transfected mouse cells. Mice were infected intranasally with the recombinant, vIL-10-containing MHV-76 or control virus strains and assayed at various days post infection for lung virus titer, spleen cell number, percentage of latently infected spleen cells and ability to reactivate virus from spleen cells.

Results: Recombinant murine gammaherpesvirus expressing EBV vIL-10 rose to significantly higher titers in lungs and promoted an increase in spleen cell number in infected mice in comparison to MHV strains lacking the vIL-10 gene. However, vIL-10 expression did not alter the quantity of latent virus in the spleen or its ability to reactivate.

Conclusions: In this mouse model of gammaherpesvirus infection, EBV vIL-10 appears to influence acute-phase pathogenicity. Given that EBV and MHV wild-type strains contain other genes that induce cIL-10 expression in latency (e.g. LMP-1 and M2, respectively), vIL-10 may have evolved to serve the specific role in acute infection of enlarging the permissive host cell population, perhaps to facilitate initial survival and dissemination of viral-infected cells.

No MeSH data available.


Related in: MedlinePlus

vIL-10 is expressed in transfected cells. NIH-3T3 cells were transfected with plasmid containing the Pgp150.vIL10 expression cassette or control plasmid (pGL3-Promoter) and infected or not with MHV-76 at a MOI of 1. After 24, 36, and 48 hours, supernatant was tested for the presence of vIL-10 by ELISA. Data points represent the averages of two readings of each sample in duplicate experiments. Error bars indicate +/- 1 standard deviation.
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Figure 2: vIL-10 is expressed in transfected cells. NIH-3T3 cells were transfected with plasmid containing the Pgp150.vIL10 expression cassette or control plasmid (pGL3-Promoter) and infected or not with MHV-76 at a MOI of 1. After 24, 36, and 48 hours, supernatant was tested for the presence of vIL-10 by ELISA. Data points represent the averages of two readings of each sample in duplicate experiments. Error bars indicate +/- 1 standard deviation.

Mentions: For expression of the EBV vIL-10 gene in MHV-76, we utilized the MHV-68 M7 late-gene promoter which allows transcription of the gp150 protein. A 660-bp fragment from upstream of the gp150 start codon was amplified by PCR and inserted directly upstream of the luciferase gene in Promega’s pGL3-basic vector. The promoter was successful in driving expression of luciferase when the plasmid was transfected into NIH-3T3 cells with or without MHV-76 viral infection (data not shown). The luciferase coding sequences were then replaced with the coding sequences for EBV vIL-10. The new constructs were successful in expressing vIL-10 in NIH-3T3 cells with similar expression levels in uninfected cells and in cells infected with MHV-76 (Figure 2).


Epstein-Barr virus IL-10 gene expression by a recombinant murine gammaherpesvirus in vivo enhances acute pathogenicity but does not affect latency or reactivation.

Lindquester GJ, Greer KA, Stewart JP, Sample JT - Herpesviridae (2014)

vIL-10 is expressed in transfected cells. NIH-3T3 cells were transfected with plasmid containing the Pgp150.vIL10 expression cassette or control plasmid (pGL3-Promoter) and infected or not with MHV-76 at a MOI of 1. After 24, 36, and 48 hours, supernatant was tested for the presence of vIL-10 by ELISA. Data points represent the averages of two readings of each sample in duplicate experiments. Error bars indicate +/- 1 standard deviation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4199788&req=5

Figure 2: vIL-10 is expressed in transfected cells. NIH-3T3 cells were transfected with plasmid containing the Pgp150.vIL10 expression cassette or control plasmid (pGL3-Promoter) and infected or not with MHV-76 at a MOI of 1. After 24, 36, and 48 hours, supernatant was tested for the presence of vIL-10 by ELISA. Data points represent the averages of two readings of each sample in duplicate experiments. Error bars indicate +/- 1 standard deviation.
Mentions: For expression of the EBV vIL-10 gene in MHV-76, we utilized the MHV-68 M7 late-gene promoter which allows transcription of the gp150 protein. A 660-bp fragment from upstream of the gp150 start codon was amplified by PCR and inserted directly upstream of the luciferase gene in Promega’s pGL3-basic vector. The promoter was successful in driving expression of luciferase when the plasmid was transfected into NIH-3T3 cells with or without MHV-76 viral infection (data not shown). The luciferase coding sequences were then replaced with the coding sequences for EBV vIL-10. The new constructs were successful in expressing vIL-10 in NIH-3T3 cells with similar expression levels in uninfected cells and in cells infected with MHV-76 (Figure 2).

Bottom Line: Many viral genes affect cytokine function within infected hosts, with interleukin 10 (IL-10) as a commonly targeted mediator.Recombinant murine gammaherpesvirus expressing EBV vIL-10 rose to significantly higher titers in lungs and promoted an increase in spleen cell number in infected mice in comparison to MHV strains lacking the vIL-10 gene.Given that EBV and MHV wild-type strains contain other genes that induce cIL-10 expression in latency (e.g. LMP-1 and M2, respectively), vIL-10 may have evolved to serve the specific role in acute infection of enlarging the permissive host cell population, perhaps to facilitate initial survival and dissemination of viral-infected cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biology, Rhodes College, Memphis, TN 38112, USA.

ABSTRACT

Background: Many viral genes affect cytokine function within infected hosts, with interleukin 10 (IL-10) as a commonly targeted mediator. Epstein-Barr virus (EBV) encodes an IL-10 homologue (vIL-10) expressed during productive (lytic) infection and induces expression of cellular IL-10 (cIL-10) during latency. This study explored the role of vIL-10 in a murine gammaherpesvirus (MHV) model of viral infection.

Methods: The EBV vIL-10 gene was inserted into MHV-76, a strain which lacks the ability to induce cIL-10, by recombination in transfected mouse cells. Mice were infected intranasally with the recombinant, vIL-10-containing MHV-76 or control virus strains and assayed at various days post infection for lung virus titer, spleen cell number, percentage of latently infected spleen cells and ability to reactivate virus from spleen cells.

Results: Recombinant murine gammaherpesvirus expressing EBV vIL-10 rose to significantly higher titers in lungs and promoted an increase in spleen cell number in infected mice in comparison to MHV strains lacking the vIL-10 gene. However, vIL-10 expression did not alter the quantity of latent virus in the spleen or its ability to reactivate.

Conclusions: In this mouse model of gammaherpesvirus infection, EBV vIL-10 appears to influence acute-phase pathogenicity. Given that EBV and MHV wild-type strains contain other genes that induce cIL-10 expression in latency (e.g. LMP-1 and M2, respectively), vIL-10 may have evolved to serve the specific role in acute infection of enlarging the permissive host cell population, perhaps to facilitate initial survival and dissemination of viral-infected cells.

No MeSH data available.


Related in: MedlinePlus