Respiratory syncytial virus infection of neonatal monocytes stimulates synthesis of interferon regulatory factor 1 and interleukin-1beta (IL-1beta)-converting enzyme and secretion of IL-1beta.
Interleukin-1beta (IL-1beta) production in response to respiratory syncytial virus (RSV) was investigated in normal neonate monocytes. Intracellular or culture supernatant IL-1beta protein levels were measured by enzyme immunoassay. The expression of mRNAs for interferon regulatory factor 1 (IRF-1), IL-1beta-converting enzyme (ICE), and IL-1beta in the cells was analyzed semiquantitatively by reverse transcriptase-PCR. Before RSV exposure, some IRF-1, ICE, and IL-1beta transcripts were already expressed in the monocytes. The levels of these transcripts increased significantly 2 h after RSV exposure compared with those in mock-infected cells. At that time, significantly higher intracellular IL-1beta protein levels were observed in RSV-exposed cells. After 20 h of RSV exposure, quantities of soluble IL-1beta secreted from RSV-exposed cells were moderately higher than those from noninfected cells. These observations suggest that RSV infection of neonatal monocytes triggers enhanced transcription and increased translation of the IL-1beta gene and increased secretion of the soluble protein. The later phase of these processes may be promoted by ICE activity, which was upregulated by increased IRF-1. The increase in IRF-1 activity may also result from RSV infection.
Takeuchi
R
R
Department of Pediatrics, Sapporo Medical University School of Medicine, Japan.
Tsutsumi
H
H
Osaki
M
M
Sone
S
S
Imai
S
S
Chiba
S
S
D017209:Apoptosis; D001483:Base Sequence; D020170:Caspase 1; D003546:Cysteine Endopeptidases / Q000096:biosynthesis* / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D066298:In Vitro Techniques; D007231:Infant, Newborn; D050856:Interferon Regulatory Factor-1; D007375:Interleukin-1 / Q000235:genetics / Q000378:metabolism*; D009000:Monocytes / Q000276:immunology* / Q000378:metabolism / Q000821:virology*; D010750:Phosphoproteins / Q000096:biosynthesis* / Q000235:genetics; D016133:Polymerase Chain Reaction; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012136:Respiratory Syncytial Viruses / Q000276:immunology / Q000472:pathogenicity*; D014158:Transcription, Genetic
D017931:DNA Primers; D004268:DNA-Binding Proteins; C494257:IRF1 protein, human; D050856:Interferon Regulatory Factor-1; D007375:Interleukin-1; D010750:Phosphoproteins; D012333:RNA, Messenger; D003546:Cysteine Endopeptidases; D020170:Caspase 1