Cutting edge: Epstein-Barr virus transactivates the HERV-K18 superantigen by docking to the human complement receptor 2 (CD21) on primary B cells.
EBV, a ubiquitous human herpesvirus, is the causative agent of infectious mononucleosis and is associated with many carcinomas. We have previously shown that the EBV latent genes LMP-1 and LMP-2A (for latent membrane proteins 1 and 2A), transactivate a human endogenous retrovirus (HERV), HERV-K18, in infected B lymphocytes. The envelope (Env) protein of HERV-K18 encodes a superantigen that strongly stimulates a large number of T cells. In this study we report that HERV-K18 env is transactivated even earlier in the infection process, before the establishment of latency; namely, we found that EBV, through its interaction with its cellular receptor CD21, induces the HERV-K18 env gene in resting B lymphocytes. This transactivation is direct and immediate, as up-regulation of transcripts can be detected within 30 min after EBV exposure. Thus, EBV binding to human CD21 on resting B cells triggers the expression of an endogenous superantigen. The biological significance of this superantigen expression for the EBV life cycle is discussed.
Hsiao
Francis C
FC
Department of Pathology, Tufts University School of Medicine, 150 Harrison Avenue, Boston, MA 02111, USA.
Lin
Miao
M
Tai
Albert
A
Chen
Gang
G
Huber
Brigitte T
BT
D000818:Animals; D016175:B-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism / Q000821:virology; D002478:Cells, Cultured; D004854:Herpesvirus 4, Human / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D014066:Palatine Tonsil / Q000166:cytology / Q000276:immunology / Q000378:metabolism / Q000821:virology; D017464:Receptors, Complement 3d / Q000235:genetics / Q000378:metabolism*; D018089:Superantigens / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism*; D015533:Transcriptional Activation; D014775:Virus Activation / Q000276:immunology*
C107453:ERVK-18 protein, human; D008565:Membrane Proteins; D017464:Receptors, Complement 3d; D018089:Superantigens