Induction of endogenous human cytomegalovirus gene expression after differentiation of monocytes from healthy carriers.
Monocytes are one site of carriage of the human cytomegalovirus (HCMV) genome in healthy human carriers. However, as there are conflicting data detailing the level of HCMV gene expression during persistence in these cells, we have analyzed monocytes for evidence of viral immediate-early, early, and late transcription by using reverse transcription followed by PCR. We were unable to find evidence of HCMV lytic gene transcription in freshly isolated peripheral blood monocytes from HCMV-seropositive subjects. However, as differentiation of monocytes to monocyte-derived macrophages results in increased permissiveness to infection with HCMV in vitro, we examined whether such differentiation could result in reactivation of endogenous viral gene expression. Here we show that in vitro differentiation of monocytes does result in expression of endogenous HCMV immediate-early genes. Although this differentiation led to reactivation of endogenous viral immediate-early expression, we were unable to detect any early or late viral transcription. Cocultivation experiments correlated with this level of gene induction, as no productive infection was detected. These data strongly suggest a mechanism of persistence of HCMV in the peripheral blood that is independent of HCMV lytic gene expression and that initial phases of lytic gene expression in monocytes can be induced by differentiation of these cells to monocyte-derived macrophages.
Taylor-Wiedeman
J
J
Department of Medicine, University of Cambridge, United Kingdom.
Sissons
P
P
Sinclair
J
J
D000328:Adult; D000956:Antigens, Viral / Q000096:biosynthesis*; D001483:Base Sequence; D002353:Carrier State / Q000382:microbiology*; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D003587:Cytomegalovirus / Q000235:genetics*; D003586:Cytomegalovirus Infections / Q000097:blood / Q000235:genetics*; D015967:Gene Expression Regulation, Viral; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006262:Health; D006801:Humans; D017874:Immediate-Early Proteins / Q000096:biosynthesis*; D008264:Macrophages / Q000166:cytology / Q000382:microbiology; D008969:Molecular Sequence Data; D009000:Monocytes / Q000166:cytology / Q000382:microbiology; D016133:Polymerase Chain Reaction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014158:Transcription, Genetic; D015533:Transcriptional Activation
D000956:Antigens, Viral; D017874:Immediate-Early Proteins; C044582:immediate-early proteins, cytomegalovirus; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D013755:Tetradecanoylphorbol Acetate