Human pegivirus RNA is found in multiple blood mononuclear cells in vivo and serum-derived viral RNA-containing particles are infectious in vitro

• Published in: Journal of general virology Vol. 95; no. 6; pp. 1307 - 1319
• Main Authors: Chivero, Ernest T., Bhattarai, Nirjal, Rydze, Robert T., Winters, Mark A., Holodniy, Mark, Stapleton, Jack T.
• Format: Journal Article
• Language: English
• Published: England Society for General Microbiology 01.06.2014
• Subjects: Adult; Amino Acid Sequence; Animal; B-Lymphocytes - virology; Base Sequence; CD4-Positive T-Lymphocytes - virology; CD8-Positive T-Lymphocytes - virology; Conserved Sequence; Female; Flaviviridae Infections - complications; Flaviviridae Infections - virology; GB virus C - genetics; GB virus C - isolation & purification; GB virus C - pathogenicity; Hepatitis, Viral, Human - complications; Hepatitis, Viral, Human - virology; HIV Infections - complications; Humans; Killer Cells, Natural - virology; Leukocytes, Mononuclear - virology; Male; Middle Aged; Molecular Sequence Data; Monocytes - virology; Phylogeny; RNA Helicases - genetics; RNA, Viral - blood; RNA, Viral - genetics; Serine Endopeptidases - genetics; Viral Nonstructural Proteins - genetics; Virulence; Young Adult
• DOI: 10.1099/vir.0.063016-0
• ISSN: 0022-1317; 1465-2099

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.