Human herpesvirus-6B induces expression of the human endogenous retrovirus K18-encoded superantigen.
BACKGROUND
The superantigen, encoded by the envelope gene (env) of the human endogenous retrovirus (HERV)-K18, may be involved in autoimmunity. Its expression is transactivated in B cells during infection with Epstein-Barr virus and in peripheral blood mononuclear cells (PBMCs) that are treated with IFN-alpha.


OBJECTIVE
We investigated whether HHV-6B infection was able to induce the expression of HERV-K18 env.


METHODS
The expression of HERV-K18 env gene was measured by real-time quantitative PCR in HHV-6B-infected PBMC.


RESULTS
Infection of PBMCs with HHV-6B resulted in a rapid and dose-dependent induction of HERV-K18 env gene expression, predominantly in monocytes. Induction was dependent on the interaction of glycoprotein H with CD46, but did not require viral transcription or DNA synthesis. Cycloheximide inhibited both the induction and basal expression of HERV-K18 env, indicating that de novo synthesis of proteins was necessary.


CONCLUSIONS
HHV-6B induced transcriptional activation of the endogenous superantigen HERV-K18 independently of virus replication, which may have consequences for the development of autoimmunity.
Turcanova
Vanda Lauridsen
VL
Department of Medical Microbiology and Immunology, Aarhus University, Denmark. vt@microbiology.au.dk
Bundgaard
Bettina
B
Höllsberg
Per
P
D002478:Cells, Cultured; D020077:Endogenous Retroviruses / Q000502:physiology*; D020869:Gene Expression Profiling; D015654:Herpesvirus 6, Human / Q000502:physiology*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000821:virology; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000235:genetics; D018089:Superantigens / Q000096:biosynthesis* / Q000235:genetics
C107453:ERVK-18 protein, human; D008565:Membrane Proteins; D018089:Superantigens