title: TT virus (TTV) loads associated with different peripheral blood cell types and evidence for TTV replication in activated mononuclear cells.
abstract: TT virus (TTV) loads associated with the peripheral blood cells of seven patients known to carry the virus in plasma were investigated by real-time PCR. Whereas red cells/platelets were uniformly negative, six and four patients yielded positive peripheral blood mononuclear cells (PBMCs) and polymorphonuclear leukocytes, respectively, but viral titres were generally low. Fractionation of PBMCs into monocyte- and B, T4, and T8 lymphocyte-enriched subpopulations showed no pattern in the viral loads that might suggest the preferential association of TTV to one or more specific cell types. TTV-negative PBMCs absorbed measurable amounts of virus when incubated with infected plasma at 4 degrees C. Furthermore, cultures of TTV-negative phytohaemagglutinin-stimulated PBMCs exposed in vitro to virus-positive plasma and faecal extracts released considerable levels of infectious TTV into the supernatant fluid and the same was true for TTV-positive stimulated PBMCs. These results indicate that, whereas freshly harvested resting PBMCs seem to produce little, if any TTV, stimulated PBMCs actively replicate the virus.
authors.affiliation: Virology Section and Retrovirus Centre, Department of Biomedicine, University of Pisa, Via San Zeno 37, I-56127 Pisa, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Maggi
authors.forename: C
authors.initials: C
authors.lastname: Fornai
authors.forename: L
authors.initials: L
authors.lastname: Zaccaro
authors.forename: A
authors.initials: A
authors.lastname: Morrica
authors.forename: M L
authors.initials: ML
authors.lastname: Vatteroni
authors.forename: P
authors.initials: P
authors.lastname: Isola
authors.forename: S
authors.initials: S
authors.lastname: Marchi
authors.forename: A
authors.initials: A
authors.lastname: Ricchiuti
authors.forename: M
authors.initials: M
authors.lastname: Pistello
authors.forename: M
authors.initials: M
authors.lastname: Bendinelli
mesh_terms: D000328:Adult; D000368:Aged; D002478:Cells, Cultured; D004266:DNA Virus Infections / Q000097:blood / Q000821:virology*; D004279:DNA, Viral / Q000032:analysis; D005243:Feces / Q000821:virology; D005260:Female; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000821:virology; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000821:virology; D016133:Polymerase Chain Reaction; D022783:Torque teno virus / Q000235:genetics / Q000302:isolation & purification*; D019562:Viral Load
chemical_list: D004279:DNA, Viral