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. 2010 Nov 30;107(48):20738-43.
doi: 10.1073/pnas.1009635107. Epub 2010 Nov 12.

V体育安卓版 - Human T-cell leukemia virus type 1 p8 protein increases cellular conduits and virus transmission

Nancy Van Prooyen  1 , Heather Gold, Vibeke Andresen, Owen Schwartz, Kathryn Jones, Frank Ruscetti, Stephen Lockett, Prabhakar Gudla, David Venzon, Genoveffa Franchini
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VSports在线直播 - Human T-cell leukemia virus type 1 p8 protein increases cellular conduits and virus transmission

Nancy Van Prooyen et al. Proc Natl Acad Sci U S A. .

Abstract

The human T-cell leukemia virus type 1 (HTLV-1) is the cause of adult T-cell leukemia/lymphoma as well as tropical spastic paraparesis/HTLV-1-associated myelopathy VSports手机版. HTLV-1 is transmitted to T cells through the virological synapse and by extracellular viral assemblies. Here, we uncovered an additional mechanism of virus transmission that is regulated by the HTLV-1-encoded p8 protein. We found that the p8 protein, known to anergize T cells, is also able to increase T-cell contact through lymphocyte function-associated antigen-1 clustering. In addition, p8 augments the number and length of cellular conduits among T cells and is transferred to neighboring T cells through these conduits. p8, by establishing a T-cell network, enhances the envelope-dependent transmission of HTLV-1. Thus, the ability of p8 to simultaneously anergize and cluster T cells, together with its induction of cellular conduits, secures virus propagation while avoiding the host's immune surveillance. This work identifies p8 as a viral target for the development of therapeutic strategies that may limit the expansion of infected cells in HTLV-1 carriers and decrease HTLV-1-associated morbidity. .

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"V体育官网" Conflict of interest statement

The authors declare no conflict of interest.

Figures

Fig. 1.
Fig. 1.
p8 but not p12 increases T-cell contact and virus transmission. (A) Jurkat T cells were transfected with the WT HTLV-1 pAB, p12KO, Δenv (defective in the envelope gene), or Δint (defective in the integrase gene) molecular clones with and without p12 or p8. After 24 h from transfection, the Jurkat T cells were cocultured with the BHK1E6 cells. The data are representative of three independent experiments. Western blots analysis of p12-HA and p8-HA expression and tubulin as control are shown (Bottom). (B) p8-HA, p12-HA, and control pME transfected Jurkat T cells were mixed at a 1:1 ratio with untransfected Jurkat T cells prestained with CellTracker Orange (blue) for 20 min, fixed, and stained with anti-HA antibody and Alexa-488 (red). (Scale bar, 10 μm.) (C) Effects of inhibitors of microtubule (1 μM nocodazole) and actin (1 μM cytochalasin D) on cell conjugation (>300 cells were analyzed and counted per each condition) following transfection of Jurkat T cells with pME, p12-HA, or p8-HA. (D) Deconvolution confocal image of one untransfected (bottom cell) and one p8-HA–expressing (red, top cell) Jurkat T cell stained with LFA-1 on the cell surface (green). (Scale bar, 5 μm.) (E) Jurkat T cells were plated on ICAM-1 Fc-coated coverslips for 30 min at 37 °C. Adhesion was measured as a percentage of adherent cells of the total cells added per well. Values are mean ± SEM of quadruplicate experiments. MT-2 cells were transfected with pME, p12-HA, or p8-HA expression vectors and mixed at a 1:1 ratio with freshly isolated PBMCs that were in a resting state or stimulated with antibodies toward CD3 and CD28 or PMA/ionomycin (for 24 h), then stained with CellTracker Orange (blue). Cells were stained with anti-HA (red), Gag (green), and Env (blue) and imaged on a confocal microscope. (F) An example a single optical section (1 μm) of the formation of a conduit between one MT-2 T cell expressing p8-HA (donor) and two resting PBMCs. (Scale bar, 10 μm.) (G) Quantification of the percentage of conduits (a minimum of 40 cells analyzed per conditions) formed among MT-2 and resting or stimulated PBMCs (**P = 0.005).
Fig. 2.
Fig. 2.
p8 protein is transferred to T cells and induces cellular conduits. (A) p8 (in red) is seen in a neighboring untransfected Jurkat T cell prestained with CellTracker Orange (blue) for 20 min. This picture was obtained 20 min after coculture of expressing and prestained untransfected Jurkat T cells. (Scale bar, 5 μm.) (B) Relative mean intensity of HA-staining in prestained untransfected Jurkat T cells (blue) cocultured with p8-HA or p12-HA–expressing (C–E) Jurkat T cells (>80 cells counted per condition). Jurkat T cells were left untransfected or transfected with Tax1 with or without p12-HA or p8-HA and mixed with untransfected Jurkat T cells. For each condition, 40 cells were analyzed. We enumerated the percent of cells forming conduits (C), the length of each TNT conduit (D), and the number of conduits per cell (E). Jurkat T cells were cotransfected with the HTLV-1 pAB or the p12KO molecular clones with or without p12 and p8 and mixed with prestained untransfected Jurkat T cells. The percent of cell conjugates (F) and the number of cells with conduits (G) was calculated on more than 50 cells per condition.
Fig. 3.
Fig. 3.
p8 increases virus transmission from chronically HTLV-1–infected T cells. (A) Coculture of MT-2 cells expressing pME, p12, or p8 with the BHK1E6 cells and enumeration of cells expressing β-gal. Bottom: Western blot to confirm the expression of p8 and p12 as well as of tubulin as a control. (B) MT-2 T cells (donor cells) were transfected with HA-tagged pME, p12, or p8 and mixed at a 1:1 ratio with untransfected prestained Jurkat T cells (blue) and the percentage of cells with conjugates were counted. (C) The MT-2 were mixed with Jurkat T cells CellTracker Orange (blue) for 20 min and fixed and stained with anti-HA (red) and anti–HTLV-1 gag (green) antibodies. (Scale bar, 5 μm.) (D) The confocal image illustrates a MT-2 cell transfected with p8-HA (red) surrounded by several prestained untransfected Jurkat T cells (blue) and several long cellular conduits. (Scale bar, 10 μm.) (E) In the coculture of MT-2 cell and Jurkat T cells, we calculated the percentage of MT-2 cells with conduits, (F) the length of conduits, and (G) the number of cells containing at least one conduit of 5 μm or longer. The length of each of the conduits was calculated on Fiji Simple Neurite Tracer on more than 50 cells.
Fig. 4.
Fig. 4.
Kinetics of p8 and virus transfer throughout conduits. (A) MT-2 cells were cotransfected with NC-YFP HTLV-1 construct and the p8-mCherry protein (red) and mixed with untransfected Jurkat T cells. Time-lapse microscopy reveals that cellular conduits form within minutes in an MT-2 cell. White arrows indicate transfer of NC-YFP (green) within a cellular conduit to Jurkat T cells. The red arrow indicates the formation of a conduit not directed toward a neighboring T cell. (Scale bar, 10 μm.) (B–D) Transmission EM of p8-HA transfected MT-2 T cells mixed with target Jurkat T cells. Virus particles are indicated by a black arrow at the junction between two conduits or by a white arrow at the junction between a conduit and a cell. (B) Scale bar, 2 μm. (C–D) Scale bar, 500 nm. (E) Model of the effect of p12 and p8 on HTLV-1 transmission and immune evasion. An HTLV-1–infected cell (donor), depicted in the center in purple, upon TCR ligation, produces a low level of virus (because p8, by decreasing TCR proximal signaling, decreases NFAT and Tax activity) and escapes immune recognition by CD8+ T cells (CTL in green) and NK cells (in yellow) because the orf-I gene down-regulates MHC-I and ICAM-1 and ICAM 2. The expression of p8 in the donor cell increases LFA-1 clustering that in turn recruits T cells (in red). p8-induced conduit formation allows rapid transfer of p8 and virus to all T cells. The newly infected cell will also be anergized by p8. This strategy confers further protection from CTL killing of the donor infected cells, when the newly infected cell is a CTL because the p8-induced down-regulation of TCR will further weaken MHC-I/TCR interaction and inhibit cell killing. This model explains how the perpetuation of this cycle can influence virus persistence in an immune competent host and why HTLV-1–infected individuals have some degree of immune deficiency (46).
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References (V体育ios版)

    1. Poiesz BJ, et al. Detection and isolation of type C retrovirus particles from fresh and cultured lymphocytes of a patient with cutaneous T-cell lymphoma. Proc Natl Acad Sci USA. 1980;77:7415–7419. - PMC (V体育ios版) - PubMed
    1. Gallo RC. The first human retrovirus. Sci Am. 1986;255:88–98. - PubMed (V体育官网入口)
    1. Gessain A, et al. Antibodies to human T-lymphotropic virus type I in patients with tropical spastic paraparesis. Lancet. 1985;2:407–410. - PubMed (VSports)
    1. Koralnik IJ, et al. Protein isoforms encoded by the pX region of human T-cell leukemia/lymphotropic virus type I. Proc Natl Acad Sci USA. 1992;89:8813–8817. - PMC - PubMed
    1. Ciminale V, et al. Expression and characterization of proteins produced by mRNAs spliced into the X region of the human T-cell leukemia/lymphotropic virus type II. Virology. 1995;209:445–456. - PubMed

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