Novel activation of gamma-interferon in nonimmune cells during human cytomegalovirus replication.
This is the first study documenting the induction of gamma-interferon (IFN-gamma) in human embryonic fibroblasts during human cytomegalovirus (HCMV) replication. Infection of cells with HCMV resulted in the consistent production of IFN-gamma RNA, as determined by RT-PCR and Northern blot analysis. Western blot analysis of cell lysates and immunoprecipitates from the cultural fluids of infected cells demonstrated the presence of IFN-gamma at the protein level. Induction of IFN-gamma required infectious HCMV, since high-dose ultraviolet inactivation of the virus stock eliminated IFN-gamma production. Further, IFN-gamma induction appears to be a late event in the virus replication cycle, since inhibition of HCMV DNA synthesis (e.g., phosphonoacetic acid) blocked the increase in IFN-gamma. Soluble factor(s) released from HCMV-infected cells apparently did not contribute to the induction of IFN-gamma, since virus stocks from which virus had been removed by sedimentation did not induce production of IFN-gamma. The appearance of IFN-gamma at late stages of HCMV infection and its elimination in the presence of an inhibitor (Actinomycin D) of RNA synthesis indicate a true transcriptional induction of this lymphokine at the RNA and protein levels. The significance of IFN-gamma production with regard to the replication and pathogenesis of HCMV in vitro and in vivo will require further investigation.
Boldogh
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Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston 77555-1019, USA.
Bui
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Szaniszlo
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Bresnahan
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Albrecht
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Hughes
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D015152:Blotting, Northern; D015153:Blotting, Western; D002460:Cell Line; D003587:Cytomegalovirus / Q000502:physiology*; D004261:DNA Replication / Q000187:drug effects; D004279:DNA, Viral / Q000235:genetics; D003609:Dactinomycin / Q000494:pharmacology; D005347:Fibroblasts; D005786:Gene Expression Regulation; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis* / Q000235:genetics / Q000494:pharmacology; D007700:Kinetics; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D010746:Phosphonoacetic Acid / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D012313:RNA / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins; D014466:Ultraviolet Rays; D014779:Virus Replication / Q000187:drug effects
D004279:DNA, Viral; D019384:Nucleic Acid Synthesis Inhibitors; D011994:Recombinant Proteins; D003609:Dactinomycin; D012313:RNA; D007371:Interferon-gamma; D010746:Phosphonoacetic Acid