title: Tax secretion from peripheral blood mononuclear cells and Tax detection in plasma of patients with human T-lymphotropic virus-type 1-associated myelopathy/tropical spastic paraparesis and asymptomatic carriers.
abstract: Human T-lymphotropic virus-type 1 (HTLV-1) is the etiologic agent of the neurologic disease HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Tax viral protein plays a critical role in viral pathogenesis. Previous studies suggested that extracellular Tax might involve cytokine-like extracellular effects. We evaluated Tax secretion in 18 h-ex vivo peripheral blood mononuclear cells (PBMCs) cultures from 15 HAM/TSP patients and 15 asymptomatic carriers. Futhermore, Tax plasma level was evaluated from other 12 HAM/TSP patients and 10 asymptomatic carriers. Proviral load and mRNA encoding Tax were quantified by PCR and real-time RT-PCR, respectively. Intracellular Tax in CD4(+)CD25(+) cells occurred in 100% and 86.7% of HAM/TSP patients and asymptomatic carriers, respectively. Percentage of CD4(+)CD25(+) Tax+, proviral load and mRNA encoding Tax were significantly higher in HAM/TSP patients. Western blot analyses showed higher secretion levels of ubiquitinated Tax in HAM/TSP patients than in asymptomatic carriers. In HTLV-1-infected subjects, Western blot of plasma Tax showed higher levels in HAM/TSP patients than in asymptomatic carriers, whereas no Tax was found in non-infected subjects. Immunoprecipitated plasma Tax resolved on SDS-PAGE gave two major bands of 57 and 48 kDa allowing identification of Tax and Ubiquitin peptides by mass spectrometry. Relative percentage of either CD4(+)CD25(+) Tax+ cells, or Tax protein released from PBMCs, or plasma Tax, correlates neither with tax mRNA nor with proviral load. This fact could be explained by a complex regulation of Tax expression. Tax secreted from PBMCs or present in plasma could potentially become a biomarker to distinguish between HAM/TSP patients and asymptomatic carriers.
authors.affiliation: Faculty of Chemical and Pharmaceutical Sciences, Department of Biochemistry and Molecular Biology, University of Chile, Santiago, Chile.
authors.forename: Fernando
authors.initials: F
authors.lastname: Medina
authors.affiliation: Faculty of Chemical and Pharmaceutical Sciences, Department of Biochemistry and Molecular Biology, University of Chile, Santiago, Chile.
authors.forename: Sebastián
authors.initials: S
authors.lastname: Quintremil
authors.affiliation: Faculty of Chemical and Pharmaceutical Sciences, Department of Biochemistry and Molecular Biology, University of Chile, Santiago, Chile.
authors.forename: Carolina
authors.initials: C
authors.lastname: Alberti
authors.affiliation: Faculty of Chemical and Pharmaceutical Sciences, Department of Biochemistry and Molecular Biology, University of Chile, Santiago, Chile.
authors.forename: Fabián
authors.initials: F
authors.lastname: Godoy
authors.affiliation: Faculty of Chemical and Pharmaceutical Sciences, Department of Biochemistry and Molecular Biology, University of Chile, Santiago, Chile.
authors.forename: María E
authors.initials: ME
authors.lastname: Pando
authors.affiliation: Faculty of Chemical and Pharmaceutical Sciences, Department of Biochemistry and Molecular Biology, University of Chile, Santiago, Chile.
authors.forename: Andrés
authors.initials: A
authors.lastname: Bustamante
authors.affiliation: Faculty of Chemical and Pharmaceutical Sciences, Department of Biochemistry and Molecular Biology, University of Chile, Santiago, Chile.
authors.forename: Andrés
authors.initials: A
authors.lastname: Barriga
authors.affiliation: Faculty of Medicine, Department of Neurological Sciences, University of Chile, Santiago, Chile.
authors.forename: Luis
authors.initials: L
authors.lastname: Cartier
authors.affiliation: Faculty of Chemical and Pharmaceutical Sciences, Department of Biochemistry and Molecular Biology, University of Chile, Santiago, Chile.
authors.forename: Javier
authors.initials: J
authors.lastname: Puente
authors.affiliation: Department of Immunology, Graduate School and Faculty of Medicine, University of the Ryukyus, Ryukyus, Japan.
authors.forename: Yuetsu
authors.initials: Y
authors.lastname: Tanaka
authors.affiliation: Faculty of Chemical and Pharmaceutical Sciences, Department of Biochemistry and Molecular Biology, University of Chile, Santiago, Chile.
authors.forename: María A
authors.initials: MA
authors.lastname: Valenzuela
authors.affiliation: Faculty of Medicine, Program of Virology, ICBM, University of Chile, Santiago, Chile.|Department of Virology, Public Health Institute of Chile, Santiago, Chile.
authors.forename: Eugenio
authors.initials: E
authors.lastname: Ramírez
mesh_terms: D000328:Adult; D000368:Aged; D058345:Asymptomatic Infections; D015415:Biomarkers / Q000097:blood; D002353:Carrier State / Q000821:virology; D002478:Cells, Cultured; D004279:DNA, Viral / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D016356:Gene Products, tax / Q000097:blood*; D015368:Human T-lymphotropic virus 1 / Q000235:genetics / Q000502:physiology*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000821:virology*; D008297:Male; D008875:Middle Aged; D015493:Paraparesis, Tropical Spastic / Q000821:virology*; D011533:Proviruses / Q000235:genetics; D012333:RNA, Messenger; D054875:Ubiquitination; D019562:Viral Load
chemical_list: D015415:Biomarkers; D004279:DNA, Viral; D016356:Gene Products, tax; D012333:RNA, Messenger
keywords: HAM/TSP patients; HTLV-1; Tax secretion; asymptomatic carriers