scholarly journals Envelope Is a Major Viral Determinant of the Distinct In Vitro Cellular Transformation Tropism of Human T-Cell Leukemia Virus Type 1 (HTLV-1) and HTLV-2

2006 ◽  
Vol 80 (4) ◽  
pp. 2073-2073
Author(s):  
Li Xie ◽  
Patrick L. Green
Keyword(s):  
T Cell ◽  
Leukemia Virus ◽  
Cellular Transformation ◽  
Cell Leukemia ◽  
Cell Leukemia Virus Type ◽  
Human T Cell ◽  
Viral Determinant ◽  
T Cell Leukemia Virus

scholarly journals In vitro infection of human macrophages with human T-cell leukemia virus type 1

Blood ◽  
1993 ◽  
Vol 81 (6) ◽  
pp. 1598-1606 ◽  
Author(s):  
T de Revel ◽  
A Mabondzo ◽  
G Gras ◽  
B Delord ◽  
P Roques ◽  
...  
Keyword(s):  
T Cell ◽  
Virus Type ◽  
Leukemia Virus ◽  
Cell Leukemia ◽  
Cell Leukemia Virus Type ◽  
Human Macrophages ◽  
Human T Cell ◽  
T Cell Leukemia Virus

Abstract The tropism of the human T-cell leukemia virus type 1 (HTLV-1) for the cells of monocyte-macrophage lineage was evaluated by the coculture of blood monocyte-derived macrophages, with irradiated cells of HTLV-1 producing cell lines MT2 or C91/PL. The susceptibility to HTLV-1 was assessed by the detection of viral DNA using the polymerase chain reaction method. HTLV-1 gene expression in the cells was detected using in situ hybridization and by immunofluorescent staining of viral antigen. The presence of type C virus-like particles detected by electron microscopy and the ability to infect normal cord blood lymphocytes demonstrated that the infected macrophages produced infectious virus. These results indicate that human macrophages are susceptible in vitro to productive HTLV-1 infection, and thus might be involved in the pathogenesis of HTLV-1-related diseases.

scholarly journals Molecular Interactions Involved in the Transactivation of the Human T-Cell Leukemia Virus Type 1 Promoter Mediated by Tax and CREB-2 (ATF-4)

2000 ◽  
Vol 20 (10) ◽  
pp. 3470-3481 ◽  
Author(s):  
Frederic Gachon ◽  
Sabine Thebault ◽  
Annick Peleraux ◽  
Christian Devaux ◽  
Jean-Michel Mesnard
Keyword(s):  
T Cell ◽  
Virus Type ◽  
Leukemia Virus ◽  
Viral Transcription ◽  
Cell Leukemia ◽  
Cell Leukemia Virus Type ◽  
Human T Cell ◽  
T Cell Leukemia Virus

ABSTRACT The human T-cell leukemia virus type 1 (HTLV-1) Tax protein activates viral transcription through three 21-bp repeats located in the U3 region of the HTLV-1 long terminal repeat and called Tax-responsive elements (TxREs). Each TxRE contains nucleotide sequences corresponding to imperfect cyclic AMP response elements (CRE). In this study, we demonstrate that the bZIP transcriptional factor CREB-2 is able to bind in vitro to the TxREs and that CREB-2 binding to each of the 21-bp motifs is enhanced by Tax. We also demonstrate that Tax can weakly interact with CREB-2 bound to a cellular palindromic CRE motif such as that found in the somatostatin promoter. Mutagenesis of Tax and CREB-2 demonstrates that both N- and C-terminal domains of Tax and the C-terminal region of CREB-2 are required for direct interaction between the two proteins. In addition, the Tax mutant M47, defective for HTLV-1 activation, is unable to form in vitro a ternary complex with CREB-2 and TxRE. In agreement with recent results suggesting that Tax can recruit the coactivator CREB-binding protein (CBP) on the HTLV-1 promoter, we provide evidence that Tax, CREB-2, and CBP are capable of cooperating to stimulate viral transcription. Taken together, our data highlight the major role played by CREB-2 in Tax-mediated transactivation.

In vitro infection of human macrophages with human T-cell leukemia virus type 1

Blood ◽  
1993 ◽  
Vol 81 (6) ◽  
pp. 1598-1606
Author(s):  
T de Revel ◽  
A Mabondzo ◽  
G Gras ◽  
B Delord ◽  
P Roques ◽  
...  
Keyword(s):  
T Cell ◽  
Virus Type ◽  
Leukemia Virus ◽  
Cell Leukemia ◽  
Cell Leukemia Virus Type ◽  
Human Macrophages ◽  
Human T Cell ◽  
T Cell Leukemia Virus

The tropism of the human T-cell leukemia virus type 1 (HTLV-1) for the cells of monocyte-macrophage lineage was evaluated by the coculture of blood monocyte-derived macrophages, with irradiated cells of HTLV-1 producing cell lines MT2 or C91/PL. The susceptibility to HTLV-1 was assessed by the detection of viral DNA using the polymerase chain reaction method. HTLV-1 gene expression in the cells was detected using in situ hybridization and by immunofluorescent staining of viral antigen. The presence of type C virus-like particles detected by electron microscopy and the ability to infect normal cord blood lymphocytes demonstrated that the infected macrophages produced infectious virus. These results indicate that human macrophages are susceptible in vitro to productive HTLV-1 infection, and thus might be involved in the pathogenesis of HTLV-1-related diseases.

scholarly journals Tocilizumab has no direct effect on cell lines infected with human T-cell leukemia virus type 1

2021 ◽  
Vol 49 (3) ◽  
pp. 030006052110020
Author(s):  
Yushiro Endo ◽  
Shoichi Fukui ◽  
Tomohiro Koga ◽  
Daisuke Sasaki ◽  
Hiroo Hasegawa ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Lines ◽  
Leukemia Virus ◽  
Cell Leukemia ◽  
Cell Leukemia Virus Type ◽  
Human T Cell ◽  
T Cell Leukemia Virus ◽  
T Cell Lines

Objective It remains unclear whether human T-cell leukemia virus type 1 (HTLV-1) infection influences therapeutic responses in patients with rheumatic diseases and whether immunosuppressive treatments increase the risk of HTLV-1-related complications in HTLV-1 carriers with rheumatic diseases. We examined the effects of tocilizumab (TCZ), an interleukin (IL)-6 receptor antagonist, on two HTLV-1-infected T-cell lines (HCT-5 and MT-2) in vitro. Methods We evaluated production of cytokines and chemokines, expression of HTLV-I associated genes, HTLV-1 proviral load (PVL), expression of HTLV-1 structural proteins, and apoptosis. Results There were no significant differences in cytokine and chemokine levels in the culture supernatants of HCT-5 and MT-2 cells treated with phosphate-buffered saline (PBS) or TCZ. No significant differences were detected in mRNA abundance of Tax or HBZ, PVL, expression of the HTLV-1 structural protein GAG, or apoptosis among HCT-5 and MT-2 cells treated with PBS or TCZ. Conclusions TCZ had no effect the cytokine profiles, HTLV-1 gene and protein expression, PVL, or apoptosis in HTLV-1-infected T-cell lines. Thus, TCZ treatment has no effect on HTLV-1 infection in vitro.

scholarly journals Physical Interaction of Human T-Cell Leukemia Virus Type 1 Tax with Cyclin-Dependent Kinase 4 Stimulates the Phosphorylation of Retinoblastoma Protein

2002 ◽  
Vol 22 (10) ◽  
pp. 3327-3338 ◽  
Author(s):  
Kerstin Haller ◽  
Yalin Wu ◽  
Elisabeth Derow ◽  
Iris Schmitt ◽  
Kuan-Teh Jeang ◽  
...  
Keyword(s):  
T Cell ◽  
Leukemia Virus ◽  
T Cell Leukemia ◽  
Cyclin Dependent Kinase ◽  
Cell Leukemia ◽  
Cell Leukemia Virus Type ◽  
Human T Cell ◽  
T Cell Leukemia Virus

ABSTRACT The Tax oncoprotein of human T-cell leukemia virus type 1 (HTLV-1) induces leukemia in transgenic mice and permanent T-cell growth in vitro. In transformed lymphocytes, it acts as an essential growth factor. Tax stimulates the cell cycle in the G1 phase by activating the cyclin-dependent kinase (CDK) CDK4 and CDK6 holoenzyme complexes. Here we show that Tax directly interacts with CDK4. This binding to CDK4 was specific, since Tax did not bind to either CDK2 or CDK1. The interaction with CDK4/cyclin D complexes was observed in vitro, in transfected fibroblasts, in HTLV-1-infected T cells, and in adult T-cell leukemia-derived cultures. Binding studies with several point and deletion mutants indicated that the N terminus of Tax mediates the interaction with CDK4. The Tax/CDK complex represented an active holoenzyme which capably phosphorylates the Rb protein in vitro and is resistant to repression by the inhibitor p21CIP. Binding-deficient Tax mutants failed to activate CDK4, indicating that direct association with Tax is required for enhanced kinase activity. Tax also increased the association of CDK4 with its positive cyclin regulatory subunit. Thus, protein-protein contact between Tax and the components of the cyclin D/CDK complexes provides a further mechanistic explanation for the mitogenic and immortalizing effects of this HTLV-1 oncoprotein.

scholarly journals In vitro Peptide Immunization of Target Tax Protein Human T-Cell Leukemia Virus Type 1–Specific CD4+ Helper T Lymphocytes

2006 ◽  
Vol 12 (12) ◽  
pp. 3814-3822 ◽  
Author(s):  
Hiroya Kobayashi ◽  
Toshihiro Ngato ◽  
Keisuke Sato ◽  
Naoko Aoki ◽  
Shoji Kimura ◽  
...  
Keyword(s):  
T Cell ◽  
Leukemia Virus ◽  
Cell Leukemia ◽  
Cell Leukemia Virus Type ◽  
Tax Protein ◽  
Helper T Lymphocytes ◽  
Human T Cell ◽  
T Cell Leukemia Virus

scholarly journals Host Sequences Flanking the Human T-Cell Leukemia Virus Type 1 Provirus In Vivo

2000 ◽  
Vol 74 (5) ◽  
pp. 2305-2312 ◽  
Author(s):  
India Leclercq ◽  
Franck Mortreux ◽  
Marielle Cavrois ◽  
Arnaud Leroy ◽  
Antoine Gessain ◽  
...  
Keyword(s):  
T Cell ◽  
Virus Type ◽  
Leukemia Virus ◽  
Cell Leukemia ◽  
Cell Leukemia Virus Type ◽  
Human T Cell ◽  
T Cell Leukemia Virus

ABSTRACT Human pathogenic retroviruses do not have common loci of integration. However, many factors, such as chromatin structure, transcriptional activity, DNA-protein interaction, CpG methylation, and nucleotide composition of the target sequence, may influence integration site selection. These features have been investigated by in vitro integration reactions or by infection of cell lines with recombinant retroviruses. Less is known about target choice for integration in vivo. The present study was conducted in order to assess the characteristics of cellular sequences targeted for human T-cell leukemia virus type 1 (HTLV-1) integration in vivo. Sequencing integration sites from ≥200 proviruses (19 kb of sequence) isolated from 29 infected individuals revealed that HTLV-1 integration is not random at the level of the nucleotide sequence. The virus was found to integrate in A/T-rich regions with a weak consensus sequence at positions within and without of the hexameric repeat generated during integration. These features were not associated with a preference for integration near active regions or repeat elements of the host chromosomes. Most or all of the regions of the genome appear to be accessible to HTLV-1 integration. As with integration in vitro, integration specificity in vivo seems to be determined by local features rather than by the accessibility of specific regions.

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