Human herpesvirus 7 is a T-lymphotropic virus and is related to, but significantly different from, human herpesvirus 6 and human cytomegalovirus.
An independent strain (JI) of human herpesvirus 7 (HHV-7) was isolated from a patient with chronic fatigue syndrome (CFS). No significant association could be established by seroepidemiology between HHV-7 and CFS. HHV-7 is a T-lymphotropic virus, infecting CD4+ and CD8+ primary lymphocytes. HHV-7 can also infect SUP-T1, an immature T-cell line, with variable success. Southern blot analysis with DNA probes scanning 58.8% of the human herpesvirus 6 (HHV-6) genome and hybridizing to all HHV-6 strains tested so far revealed homology to HHV-7 with only 37.4% of the total probe length. HHV-7 contains the GGGTTA repetitive sequence, as do HHV-6 and Marek's disease chicken herpesvirus. DNA sequencing of a 186-base-pair fragment of HHV-7(JI) revealed an identity with HHV-6 and human cytomegalovirus of 57.5% and 36%, respectively. Oligonucleotide primers derived from this sequence (HV7/HV8, HV10/HV11) amplified HHV-7 DNA only and did not amplify DNA from other human herpesviruses, including 12 different HHV-6 strains. Southern blot analysis with the p43L3 probe containing the 186-base-pair HHV-7 DNA fragment hybridized to HHV-7 DNA only. The molecular divergence between human cytomegalovirus, on the one hand, and HHV-6 and HHV-7, on the other, is greater than between HHV-6 and HHV-7, which, in turn, is greater than the difference between HHV-6 strains. This study supports the classification of HHV-7 as an additional member of the human beta-herpesviruses.
Berneman
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Laboratory of Tumor Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.
Ablashi
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DV
Li
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Eger-Fletcher
M
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Reitz
M S
MS
Hung
C L
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Brus
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Komaroff
A L
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Gallo
R C
RC
D000595:Amino Acid Sequence; D001483:Base Sequence; D015139:Blotting, Southern; D015704:CD4 Antigens / Q000276:immunology; D016827:CD8 Antigens / Q000276:immunology; D002460:Cell Line; D003001:Cloning, Molecular; D003587:Cytomegalovirus / Q000145:classification* / Q000235:genetics*; D015342:DNA Probes; D004279:DNA, Viral / Q000235:genetics; D015654:Herpesvirus 6, Human / Q000145:classification* / Q000235:genetics*; D016199:Herpesvirus 7, Human / Q000145:classification* / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D016133:Polymerase Chain Reaction / Q000379:methods; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013601:T-Lymphocytes / Q000382:microbiology
D015704:CD4 Antigens; D016827:CD8 Antigens; D015342:DNA Probes; D004279:DNA, Viral; D009838:Oligodeoxyribonucleotides