EBV persistence without its EBNA3A and 3C oncogenes in vivo

PLoS Pathog. 2018 Apr 30;14(4):e1007039. doi: 10.1371/journal.ppat.1007039. eCollection 2018 Apr.

Abstract

The oncogenic Epstein Barr virus (EBV) infects the majority of the human population and usually persists within its host for life without symptoms. The EBV oncoproteins nuclear antigen 3A (EBNA3A) and 3C (EBNA3C) are required for B cell transformation in vitro and are expressed in EBV associated immunoblastic lymphomas in vivo. In order to address the necessity of EBNA3A and EBNA3C for persistent EBV infection in vivo, we infected NOD-scid γcnull mice with reconstituted human immune system components (huNSG mice) with recombinant EBV mutants devoid of EBNA3A or EBNA3C expression. These EBV mutants established latent infection in secondary lymphoid organs of infected huNSG mice for at least 3 months, but did not cause tumor formation. Low level viral persistence in the absence of EBNA3A or EBNA3C seemed to be supported primarily by proliferation with the expression of early latent EBV gene products transitioning into absent viral protein expression without elevated lytic replication. In vitro, EBNA3A and EBNA3C deficient EBV infected B cells could be rescued from apoptosis through CD40 stimulation, mimicking T cell help in secondary lymphoid tissues. Thus, even in the absence of the oncogenes EBNA3A and 3C, EBV can access a latent gene expression pattern that is reminiscent of EBV persistence in healthy virus carriers without prior expression of its whole growth transforming program.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • B-Lymphocytes / metabolism
  • B-Lymphocytes / virology*
  • Cells, Cultured
  • Epstein-Barr Virus Infections / metabolism
  • Epstein-Barr Virus Infections / virology*
  • Epstein-Barr Virus Nuclear Antigens / metabolism*
  • Herpesvirus 4, Human / pathogenicity*
  • Humans
  • Mice
  • Mice, Inbred NOD
  • Mice, SCID
  • Mice, Transgenic

Substances

  • EBNA-3A antigen
  • EBNA-3C, epstein-barr virus
  • Epstein-Barr Virus Nuclear Antigens

Grants and funding

This work was supported by grants from the Swiss National Science Foundation (310030_162560 and CRSII3_160708), Cancer Research Switzerland (KFS-4091-02-2017), SPARKS (15UOZ01), Sobek Foundation, the Swiss MS Society, the Vontobel Foundation, the Swiss Vaccine Research Institute and the Forschungkredit as well as the clinical research priority programs on Multiple sclerosis (KFSPMS) and human hemato-lymphatic diseases (KFSPHHLD) of the University of Zürich to CM. Furthermore OC is recipient of a grant from Cancer Research Zurich and DM is supported by an MD-PhD fellowship from the Swiss National Science Foundation (323530_145247). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.