title: CD8(+) T cells are an in vivo reservoir for human T-cell lymphotropic virus type I.
abstract: It is thought that human T-cell lymphotropic virus type I (HTLV-I) preferentially infects CD4(+) T cells in vivo. However, observations of high HTLV-I proviral load in patients with HTLV-I-associated myelopathy/tropical spastic paraparesis suggest that HTLV-I may infect other cell types in addition to CD4(+) T cells. To identify in vivo T-cell tropisms of HTLV-I, real-time quantitative polymerase chain reaction (PCR) and intracellular protein staining were used. A high amount of HTLV-I proviral DNA was detected from purified CD8(+) T cells by quantitative PCR (between 1.64 and 62.83 copies of HTLV-I provirus per 100 isolated CD8(+) T cells). CD8(+) T cells expressed HTLV-I-related antigens (HTLV-I Tax and p19 protein) after a short time in cultivation. These results demonstrate that CD8(+) T cells are also infected with HTLV-I and express HTLV-I antigens at levels that are comparable to HTLV-I-infected CD4(+) cells. Therefore, CD8(+) cells are an additional viral reservoir in vivo for HTLV-I and may contribute to the pathogenesis of HTLV-I-mediated disorders.
authors.affiliation: Viral Immunology Section, Neuroimmunology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
authors.forename: M
authors.initials: M
authors.lastname: Nagai
authors.forename: M B
authors.initials: MB
authors.lastname: Brennan
authors.forename: J A
authors.initials: JA
authors.lastname: Sakai
authors.forename: C A
authors.initials: CA
authors.lastname: Mora
authors.forename: S
authors.initials: S
authors.lastname: Jacobson
mesh_terms: D015496:CD4-Positive T-Lymphocytes / Q000821:virology; D018414:CD8-Positive T-Lymphocytes / Q000821:virology*; D002478:Cells, Cultured; D004279:DNA, Viral / Q000032:analysis; D015683:Gene Products, gag / Q000378:metabolism; D016356:Gene Products, tax / Q000378:metabolism; D015368:Human T-lymphotropic virus 1 / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D015682:Retroviridae Proteins, Oncogenic / Q000378:metabolism; D054301:gag Gene Products, Human Immunodeficiency Virus
chemical_list: D004279:DNA, Viral; D015683:Gene Products, gag; D016356:Gene Products, tax; D015682:Retroviridae Proteins, Oncogenic; D054301:gag Gene Products, Human Immunodeficiency Virus; C060955:p19 protein, Human T-lymphotropic virus 1