title: Biphasic viremia and viral gene expression in leukocytes during acute cytomegalovirus infection of mice.
abstract: Circulating leukocytes are important in dissemination of cytomegalovirus (CMV) infection in humans. In the mouse model of murine CMV infection (MCMV), it has been shown that infection peaks on days 5 to 7 after experimental infection, when 0.01 to 0.1% of the circulating leukocytes contain viral DNA. In our laboratory, MCMV DNA was detected by in situ hybridization predominantly in the mononuclear cells on day 6 after acute infection. Infectious virus was recovered from day 6 mononuclear fractions in 16 of 16 mice compared with that from day 6 polymorphonuclear fractions in 4 of 16 mice. An eclipse phenomenon was noted in the blood leukocytes by quantitative blot hybridization: the amount of MCMV DNA present was small on day 2, diminished on days 3 and 4, and then increased markedly on days 5 and 6 in both the mononuclear and polymorphonuclear fractions immediately following viral augmentation in the liver and spleen. MCMV immediate-early and glycoprotein B (late) transcripts were present in pooled mononuclear fractions only on day 6 of acute infection but not in pooled polymorphonuclear fractions. Collectively, these data demonstrate that (i) circulating leukocytes, predominantly mononuclear, are involved in dissemination of MCMV; (ii) a primary viremia with dissemination of MCMV to reticuloendothelial organs (liver and spleen) occurs and is followed by viral amplification and a subsequent, more intense secondary viremia; and (iii) immediate-early viral mRNA and glycoprotein B mRNA transcripts are detectable only during peak infection on day 6 in mononuclear leukocytes but not in polymorphonuclear leukocytes.
authors.affiliation: Department of Medicine, University of Minnesota Medical School, Minneapolis 55455.
authors.forename: T M
authors.initials: TM
authors.lastname: Collins
authors.forename: M R
authors.initials: MR
authors.lastname: Quirk
authors.forename: M C
authors.initials: MC
authors.lastname: Jordan
mesh_terms: D000818:Animals; D001483:Base Sequence; D003587:Cytomegalovirus / Q000235:genetics* / Q000502:physiology; D003586:Cytomegalovirus Infections / Q000097:blood / Q000503:physiopathology*; D017931:DNA Primers; D004279:DNA, Viral / Q000032:analysis / Q000097:blood*; D004195:Disease Models, Animal; D005091:Exons; D005260:Female; D015870:Gene Expression; D017781:Genes, Immediate-Early; D006801:Humans; D017403:In Situ Hybridization; D007962:Leukocytes / Q000382:microbiology*; D008099:Liver / Q000382:microbiology; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000096:biosynthesis / Q000097:blood; D013154:Spleen / Q000382:microbiology; D013997:Time Factors; D014158:Transcription, Genetic; D014766:Viremia / Q000097:blood / Q000503:physiopathology*; D014779:Virus Replication
chemical_list: D017931:DNA Primers; D004279:DNA, Viral; D012333:RNA, Messenger