Epstein–Barr virus microRNAs reduce immune surveillance by virus-specific CD8+ T cells

M Albanese, T Tagawa, M Bouvet… - Proceedings of the …, 2016 - National Acad Sciences
M Albanese, T Tagawa, M Bouvet, L Maliqi, D Lutter, J Hoser, M Hastreiter, M Hayes…
Proceedings of the National Academy of Sciences, 2016National Acad Sciences
Infection with Epstein–Barr virus (EBV) affects most humans worldwide and persists life-long
in the presence of robust virus-specific T-cell responses. In both immunocompromised and
some immunocompetent people, EBV causes several cancers and lymphoproliferative
diseases. EBV transforms B cells in vitro and encodes at least 44 microRNAs (miRNAs),
most of which are expressed in EBV-transformed B cells, but their functions are largely
unknown. Recently, we showed that EBV miRNAs inhibit CD4+ T-cell responses to infected …
Infection with Epstein–Barr virus (EBV) affects most humans worldwide and persists life-long in the presence of robust virus-specific T-cell responses. In both immunocompromised and some immunocompetent people, EBV causes several cancers and lymphoproliferative diseases. EBV transforms B cells in vitro and encodes at least 44 microRNAs (miRNAs), most of which are expressed in EBV-transformed B cells, but their functions are largely unknown. Recently, we showed that EBV miRNAs inhibit CD4+ T-cell responses to infected B cells by targeting IL-12, MHC class II, and lysosomal proteases. Here we investigated whether EBV miRNAs also counteract surveillance by CD8+ T cells. We have found that EBV miRNAs strongly inhibit recognition and killing of infected B cells by EBV-specific CD8+ T cells through multiple mechanisms. EBV miRNAs directly target the peptide transporter subunit TAP2 and reduce levels of the TAP1 subunit, MHC class I molecules, and EBNA1, a protein expressed in most forms of EBV latency and a target of EBV-specific CD8+ T cells. Moreover, miRNA-mediated down-regulation of the cytokine IL-12 decreases the recognition of infected cells by EBV-specific CD8+ T cells. Thus, EBV miRNAs use multiple, distinct pathways, allowing the virus to evade surveillance not only by CD4+ but also by antiviral CD8+ T cells.
National Acad Sciences