Virus research2010; 150(1-2); 138-142; doi: 10.1016/j.virusres.2010.02.013

Curing of HeLa cells persistently infected with equine arteritis virus by a peptide-conjugated morpholino oligomer.

Abstract: A significant consequence of equine arteritis virus (EAV) infection of horses is persistence of the virus in a variable percentage of infected stallions. We recently established an in vitro model of EAV persistence in cell culture for the purpose of furthering our understanding of EAV biology in general and viral persistence in the stallion in particular. In this study we investigated whether persistently infected HeLa cells could be cured of EAV infection by treatment with an antisense peptide-conjugated phosphorodiamidate morpholino oligomer (PPMO) designed to target the 5'-terminal region of the EAV genome. We found that persistently infected HeLa cells passaged three times in the presence of 5-10 microM EAV-specific PPMO produced no detectable virus. The PPMO-cured HeLa cells were free of infectious virus, viral antigen and EAV RNA as measured by plaque assay, indirect immunofluorescence assay and RT-PCR, respectively. Furthermore, when re-challenged with EAV at several passages after discontinuation of PPMO treatments, PPMO-cured HeLa cells were found to be refractory to re-infection and to the re-establishment of viral persistence. While these findings demonstrate that PPMO can be used to eliminate persistent EAV infection in cell culture, the efficacy of PPMO against EAV in vivo remains to be addressed.
Publication Date: 2010-03-03 PubMed ID: 20206215PubMed Central: PMC7114391DOI: 10.1016/j.virusres.2010.02.013Google Scholar: Lookup
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  • Journal Article
  • Research Support
  • Non-U.S. Gov't


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The study explores the possibility of eliminating persistent equine arteritis virus (EAV) infection in HeLa cells using a peptide-conjugated morpholino oligomer (PPMO) targeting the virus’s genome. The research findings were promising, with no detectable levels of EAV after treatment. However, in vivo effectiveness remains untested.

Understanding the Research Problems

  • The study is centered on EAV, a virus infecting horses that becomes persistent in a fluctuating percentage of infected stallions. The persistence of EAV poses challenges for the health of horses.
  • Scientists created an in vitro model in recent studies to investigate the EAV’s biology and its persistence in stallions. However, this study further explores the possibility of curing EAV persistence using a unique approach – applying an antisense peptide-conjugated morpholino oligomer (PPMO).

Study Methodology and Findings

  • The researchers used a specific PPMO designed to target the 5′-terminal region of the EAV genome. This antisense molecule was applied to HeLa cells persistently infected with EAV.
  • Subsequent to the application of EAV-specific PPMO (ranging between 5-10 microM) and passing the HeLa cells through three passages, no detectable virus was found.
  • The tests confirmed that PPMO-treated HeLa cells were devoid of infectious virus, viral antigen and EAV RNA. This was determined by the plaque assay, indirect immunofluorescence assay, and RT-PC
  • Moreover, the study found that these “cured” HeLa cells remained resistant to the EAV when re-challenged with the virus, even after several passages sans the PPMO treatments.
  • Overall, the findings confirm the efficacy of PPMO in eliminating persistent EAV infection in an in vitro cell culture environment.

Pending Research Directions

  • Although the findings from this in vitro study are promising, the effectiveness of PPMO against EAV in a real-world, in vivo setting remains unaddressed. Future research needs to take this direction to confirm if PPMO treatments could indeed eliminate persistent EAV infections in stallions.

Cite This Article

Zhang J, Stein DA, Timoney PJ, Balasuriya UB. (2010). Curing of HeLa cells persistently infected with equine arteritis virus by a peptide-conjugated morpholino oligomer. Virus Res, 150(1-2), 138-142.


ISSN: 1872-7492
NlmUniqueID: 8410979
Country: Netherlands
Language: English
Volume: 150
Issue: 1-2
Pages: 138-142

Researcher Affiliations

Zhang, Jianqiang
  • Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA.
Stein, David A
    Timoney, Peter J
      Balasuriya, Udeni B R

        MeSH Terms

        • Animals
        • Antiviral Agents / chemistry
        • Antiviral Agents / pharmacology
        • Equartevirus / drug effects
        • Equartevirus / growth & development
        • HeLa Cells
        • Horses
        • Humans
        • Morpholines / chemistry
        • Morpholines / pharmacology
        • Morpholinos
        • Oligonucleotides, Antisense / chemistry
        • Oligonucleotides, Antisense / pharmacology
        • Peptides / chemistry
        • Peptides / pharmacology


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        This article has been cited 2 times.
        1. Nan Y, Zhang YJ. Antisense Phosphorodiamidate Morpholino Oligomers as Novel Antiviral Compounds.. Front Microbiol 2018;9:750.
          doi: 10.3389/fmicb.2018.00750pubmed: 29731743google scholar: lookup
        2. Balasuriya UB, Go YY, MacLachlan NJ. Equine arteritis virus.. Vet Microbiol 2013 Nov 29;167(1-2):93-122.
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