Two Types of HTLV-1 Particles Are Released from MT-2 Cells

Morozov, V A; Weiss, Robin A.

doi:10.1006/viro.1998.9578

Cited by 31 publications

(21 citation statements)

References 26 publications

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“…CA fragments in both CA-containing proviruses (class 3) were nearly 120 bp. Class 3 strongly resembles the p28 provirus present and expressed in MT-2 cells (15,25). No clear association with pathology was observed for any of the identified groups of deleted proviruses, although class 2 was more frequent in HAM/TSP patients.…”

Section: Resultsmentioning

confidence: 86%

“…These proviruses contained an open reading frame (ORF) coding for a chimeric protein (p28) composed of Gag (MA [matrix] and truncated CA [capsid]) and a short pX fragment (12). RNA transcripts for MT-2 cell defective provirus are packaged in virions and can be translated into a p28 chimeric protein (25), and they establish new provirus in culture (1). HTLV-1 proviruses with internal deletions have also been found in other cell lines (9,33) and in peripheral blood mononuclear cells (PBMC) of ATLL patients (18,31), as well as defective proviruses in human immunodeficiency virus infection (29).…”

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confidence: 99%

“…Using the p28 provirus of MT-2 cells as a prototype, we designed a set of PCR primers corresponding to the Gag and pX regions (25), which allowed us to amplify proviruses with large internal deletions provided they contained the corresponding gag and pX sequences but not the gag-pol-env-pX sequence of the completed provirus. The aim of our research was to detect and analyze possible defective proviruses with large internal deletions in HTLV-1-infected individuals with different pathologies: HAM/TSP, ATLL, and asymptomatic carriers.…”

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confidence: 99%

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Chimeric Matrix Proteins Encoded by Defective Proviruses with Large Internal Deletions in Human T-Cell Leukemia Virus Type 1-Infected Humans

Morozov

Lagaye

Taylor

et al. 2000

J Virol

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Human T-cell leukemia virus type 1 (HTLV-1) is the etiologic agent of adult T-cell leukemia/lymphoma (ATLL), HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), and other diseases. The mechanisms of virus pathogenesis are still obscure. The occurrence of defective proviruses in HTLV-1-infected cell lines and the peripheral blood mononuclear cells (PBMC) of infected individuals is a frequent feature of virus infection. We detected defective proviruses with large internal deletions in PBMC from ATLL and HAM/TSP patients and in asymptomatic HTLV-1 carriers. Seventeen PCR-amplified defective proviruses were sequenced, and three types of deletions were found. Besides truncated MA and the 5 end of the genome, truncated CA, truncated SU, and more frequently truncated TM linked to the pX region were detected. Reverse transcription-PCR analysis of PBMC from ATLL patients and asymptomatic carriers also revealed RNA transcripts with large internal deletions. Analysis of two RT-PCR cDNA clones confirmed a Gag-TM-pX structure of the transcripts. Most defective proviruses contained numerous internal stop codons, but some were capable of coding for the truncated MA linked to a variable out-of-frame peptide. Cloned defective proviruses with long open reading frames were subjected to in vitro transcription-translation followed by radioimmunoprecipitation, which showed expression of chimeric proteins between 8 and 12 kDa. Possible roles of defective proviruses and chimeric proteins are discussed, although there is no firm association with pathogenesis.The human T-cell leukemia virus type 1 (HTLV-1) is a retrovirus which causes two distinct pathologies: adult T-cell leukemia/lymphoma (ATLL) (10, 27) and chronic progressive myelopathy-tropical spastic paraparesis (TSP), also called HTLV-1-associated myelopathy (HAM) (5, 26). Recent studies have suggested that HTLV-1 is also associated with other human diseases (23).Previous comparative studies of different HTLV-1 isolates indicated the following: the protein patterns of the viruses from cells of individuals with ATL and HAM/TSP were identical (6), DNA blotting (11, 33) and sequence comparisons of proviruses from ATLL and HAM/TSP revealed nearly 97% homology (4, 21), and restriction endonuclease analysis did not reveal any selected integration sites for the proviruses in the DNA of infected individuals (33). Occasional cases of ATLL associated with TSP-HAM pathology have been reported (14,24), and infection of a patient with blood from a HAM/TSP donor resulted in HAM/TSP in the recipient (8). Thus, different diseases in association with one virus remains a paradox of HTLV-1. The mechanisms by which the virus induces different diseases and the cofactors, either virus associated or host related, that contribute to different forms of disease manifestations or progression remain to be determined.Defective proviruses have been observed in cells from ATLL patients and could be important elements in pathogenesis (9,17,32). We have therefore compared the presence of defecti...

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Section: Resultsmentioning

confidence: 86%

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confidence: 99%

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confidence: 99%

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Chimeric Matrix Proteins Encoded by Defective Proviruses with Large Internal Deletions in Human T-Cell Leukemia Virus Type 1-Infected Humans

Morozov

Lagaye

Taylor

et al. 2000

J Virol

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“…It was therefore important to determine if binding of SU-Fc to cells could be competitively blocked by native virally expressed envelope protein. Conditioned medium supernatants from HTLV-1-infected MT-2 cells contain significant amounts of virus-associated or free soluble gp46 SU (5,29). Since the viral gp46 is relatively dilute, we concentrated MT-2 medium supernatants 30-fold for these experiments.…”

Section: Vol 75 2001mentioning

confidence: 99%

Human T-Cell Leukemia Virus Type 1 Receptor Expression among Syncytium-Resistant Cell Lines Revealed by a Novel Surface Glycoprotein-Immunoadhesin

Jassal

Pöhler

Brighty

2001

J Virol

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The envelope glycoproteins of human T-cell leukemia virus type 1 (HTLV-1) perform functions that are crucial for virus entry into cells. The surface glycoprotein (SU) is responsible for viral recognition of, and binding to, target cells through its interaction with an unknown cell surface receptor. To facilitate molecular analysis of the receptor-binding properties of SU and to characterize the cellular receptor employed by HTLV-1, we have expressed a recombinant SU fused to the Fc domain of human immunoglobulin G. Here, we demonstrate that this novel SU-immunoadhesin retains both the biochemical properties of Fc and the receptorbinding specificity of the HTLV-1 SU. We use this SU-immunoadhesin to demonstrate, by direct cell surface binding assays, that the receptor used by HTLV-1 has been conserved through vertebrate evolution. Moreover, using murine-human somatic cell hybrids we provide data that do not support the previously assigned location for the HTLV-1 receptor on human chromosome 17. Most importantly, we show that many cell lines that are resistant to HTLV-1 envelope-mediated infection and syncytium formation express functional receptors that are recognized by the HTLV-1 SU. Based on our results, we suggest that for some HTLV-1-resistant cell lines the block to viral entry occurs at a late post-receptor-binding step of the entry process. Our findings will be of value in developing new strategies to identify the cellular receptor used by HTLV-1.Human T-cell leukemia virus (HTLV-1) is the etiologic agent of a rare but aggressive adult T-cell leukemia-lymphoma and a progressive demyelinating disease known as HTLV-1-associated myelopathy or tropical spastic paraparesis. HTLV-1 is endemic in Southern Japan, West Africa, Central and South America, and the Caribbean basin. Although uncommon in Europeans, HTLV-1 infections have been reported among indigenous and immigrant European populations and are prevalent among intravenous-drug users both in Europe and in the United States (reviewed in references 1, 4, 21, and 48). HTLV-1 primarily infects and immortalizes human CD4 ϩ T cells in vivo, but in in vitro coculture systems HTLV-1 infection, viral replication, and virally induced syncytium formation can be supported by a variety of primate and nonprimate cell types (1,4,30,45,46,49).The promiscuous pattern of tropism observed for HTLV-1 in vitro has generated considerable interest in the molecular events that promote viral entry into cells, and a number of informative studies have highlighted the crucial role played by the viral envelope glycoproteins in the entry process (31-36, 44). The envelope is expressed as a 68-kDa precursor that is posttranslationally cleaved by a cellular protease to yield the 46-kDa surface glycoprotein (gp46, SU) and a 21-kDa transmembrane glycoprotein (gp21, TM) (4,8,31,36). The gp46 surface glycoprotein remains associated with the transmembrane glycoprotein by noncovalent interactions following precursor cleavage, and this envelope complex is retained on the surfaces of virions or i...

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“…This cell line was grown in high-glucose Dulbecco's modified Eagle's medium (Gibco, USA) supplemented with 10% heat inactivated fetal bovine serum (FBS), 100 units-100 µg/mL penicillinstreptomycin (PAA, Austria), and 2 mM L-glutamine, and kept at 37°C in 5% CO 2 . MT2 (HTLV-1-transformed human T-cell line) (28) and Jurkat (an HTLV unrelated human Tlymphoblast-like cell line) (29) were maintained in RPMI 1640 (PAA) with the same supplements.…”

Section: Cell Lines and Culturementioning

confidence: 99%

Examination of a Reporter Vector for HTLV-1 Infectivity Using MT2, a HTLV-1 Producer Cell Line

Abdizadeh

Makvandi

Samarbafzadeh

et al. 2013

Jundishapur J Microbiol

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Background: HTLV-1 (Human T_cell lymphotropic virus type 1), with about 20 million individuals infected worldwide, is a global health problem that is endemic in certain areas such as Japan and Khorasan province of Iran.HTLV-1 is the causative agent of progressive diseases, Adult T cell Leukemia (ATL), and HTLV-I Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP), which do not yet have approved effective treatment. Due to the non-cytolytic characteristic of this virus and cell associated properties, there is no routine Procedure for drug study in vitro and it's confined to some HTLV infected cell lines. Therefore construction of a reporter vector is necessary to evaluate HTLV-1 infectivity in cell culture for drug studies, since designed reporters for retroviruses are usually based on long terminal repeat (LTR) transactivation. LTR region of HTLV-1 contains a virus promoter that plays the most important role in replication and transcription by the Tax transactivation effect. Objectives: In this project we attempted to construct a reporter vector containing the luciferase gene coupled to the HTLV-1 promoter for evaluation of HTLV-1 infectivity. Material and Methods: LTR region was digested from pUCLTR-Lac by HindIII and sub-cloned into the Multiple cloning site (MCS) region of a promoter-less reporter vector, pGL4.17, upstream to the luciferase gene. Colonies were screened by Colony PCR, then selected colonies were confirmed by restriction enzyme digestion and sequencing. Human embryonic kidney (HEK) 293T cell line was transfected by a recombinant vector and inducible expression of luciferase was evaluated. Results: Recombinant vector, pGL4LTR-Luc, has expression levels of more than 50 folds compared to the control when co-transfected with the Tax expressing vector into HEK 293T cells. Moreover, cells display more than 30 folds of luciferase expression over 2 days when cocultured with MT2 cell, a HTLV-1 producer cell line. Conclusions: According to the high functionality of the produced recombinant vector, it seems a good applicable tool for making an indicator cell line in subsequent basic and drug studies.

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Two Types of HTLV-1 Particles Are Released from MT-2 Cells

Cited by 31 publications

References 26 publications

Chimeric Matrix Proteins Encoded by Defective Proviruses with Large Internal Deletions in Human T-Cell Leukemia Virus Type 1-Infected Humans

Chimeric Matrix Proteins Encoded by Defective Proviruses with Large Internal Deletions in Human T-Cell Leukemia Virus Type 1-Infected Humans

Human T-Cell Leukemia Virus Type 1 Receptor Expression among Syncytium-Resistant Cell Lines Revealed by a Novel Surface Glycoprotein-Immunoadhesin

Examination of a Reporter Vector for HTLV-1 Infectivity Using MT2, a HTLV-1 Producer Cell Line

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