title: Human pegivirus RNA is found in multiple blood mononuclear cells in vivo and serum-derived viral RNA-containing particles are infectious in vitro.
abstract: Human pegivirus (HPgV; previously called GB virus C/hepatitis G virus) has limited pathogenicity, despite causing persistent infection, and is associated with prolonged survival in human immunodeficiency virus-infected individuals. Although HPgV RNA is found in and produced by T- and B-lymphocytes, the primary permissive cell type(s) are unknown. We quantified HPgV RNA in highly purified CD4(+) and CD8(+) T-cells, including naïve, central memory and effector memory populations, and in B-cells (CD19(+)), NK cells (CD56(+)) and monocytes (CD14(+)) using real-time reverse transcription-PCR. Single-genome sequencing was performed on viruses within individual cell types to estimate genetic diversity among cell populations. HPgV RNA was present in CD4(+) and CD8(+) T-lymphocytes (nine of nine subjects), B-lymphocytes (seven of ten subjects), NK cells and monocytes (both four of five). HPgV RNA levels were higher in naïve (CD45RA(+)) CD4(+) cells than in central memory and effector memory cells (P<0.01). HPgV sequences were highly conserved among subjects (0.117±0.02 substitutions per site; range 0.58-0.14) and within subjects (0.006±0.003 substitutions per site; range 0.006-0.010). The non-synonymous/synonymous substitution ratio was 0.07, suggesting a low selective pressure. Carboxyfluorescein succinimidyl ester (CFSE)-labelled HPgV RNA-containing particles precipitated by a commercial exosome isolation reagent delivered CSFE to uninfected monocytes, NK cells and T- and B-lymphocytes, and HPgV RNA was transferred to PBMCs with evidence of subsequent virus replication. Thus, HPgV RNA-containing serum particles including microvesicles may contribute to delivery of HPgV to PBMCs in vivo, explaining the apparent broad tropism of this persistent human RNA virus.
authors.affiliation: Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA.|Medicine Service, Iowa City Veterans Affairs Medical Center, Iowa City, IA 52246, USA.
authors.forename: Ernest T
authors.initials: ET
authors.lastname: Chivero
authors.affiliation: Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA.|Medicine Service, Iowa City Veterans Affairs Medical Center, Iowa City, IA 52246, USA.
authors.forename: Nirjal
authors.initials: N
authors.lastname: Bhattarai
authors.affiliation: Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA.
authors.forename: Robert T
authors.initials: RT
authors.lastname: Rydze
authors.affiliation: Division of Infectious Diseases, Stanford University School of Medicine, Stanford, CA 94305, USA.|AIDS Research Center, VA Palo Alto Health Care System, Palo Alto, CA 94304, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Winters
authors.affiliation: Division of Infectious Diseases, Stanford University School of Medicine, Stanford, CA 94305, USA.|AIDS Research Center, VA Palo Alto Health Care System, Palo Alto, CA 94304, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Holodniy
authors.affiliation: Department of Microbiology, University of Iowa, Iowa City, IA 52242, USA.|Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA.|Medicine Service, Iowa City Veterans Affairs Medical Center, Iowa City, IA 52246, USA.
authors.forename: Jack T
authors.initials: JT
authors.lastname: Stapleton
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D001402:B-Lymphocytes / Q000821:virology; D001483:Base Sequence; D015496:CD4-Positive T-Lymphocytes / Q000821:virology; D018414:CD8-Positive T-Lymphocytes / Q000821:virology; D017124:Conserved Sequence; D005260:Female; D018178:Flaviviridae Infections / Q000150:complications / Q000821:virology; D029407:GB virus C / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity*; D015658:HIV Infections / Q000150:complications; D006525:Hepatitis, Viral, Human / Q000150:complications / Q000821:virology; D006801:Humans; D007694:Killer Cells, Natural / Q000821:virology; D007963:Leukocytes, Mononuclear / Q000821:virology*; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D009000:Monocytes / Q000821:virology; D010802:Phylogeny; D020365:RNA Helicases / Q000235:genetics; D012367:RNA, Viral / Q000097:blood* / Q000235:genetics; D012697:Serine Endopeptidases / Q000235:genetics; D017361:Viral Nonstructural Proteins / Q000235:genetics; D014774:Virulence; D055815:Young Adult; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
chemical_list: D020365:RNA Helicases; D012367:RNA, Viral; D012697:Serine Endopeptidases; D017361:Viral Nonstructural Proteins; C060028:NS3 protein, flavivirus; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases