Publications
303 results found
Bangham CRM, Melamed A, Yaguchi H, et al., 2018, The human leukemia virus HTLV-1 alters the structure and transcription of host chromatin in cis, eLife, Vol: 7, Pages: 1-20, ISSN: 2050-084X
Chromatin looping controls gene expression by regulating promoter-enhancer contacts, the spread of epigenetic modifications, and the segregation of the genome into transcriptionally active and inactive compartments. We studied the impact on the structure and expression of host chromatin by the human retrovirus HTLV-1. We show that HTLV-1 disrupts host chromatin structure by forming loops between the provirus and the host genome; certain loops depend on the critical chromatin architectural protein CTCF, which we recently discovered binds to the HTLV-1 provirus. We show that the provirus causes two distinct patterns of abnormal transcription of the host genome in cis: bidirectional transcription in the host genome immediately flanking the provirus, and clone-specific transcription in cis at non-contiguous loci up to >300 kb from the integration site. We conclude that HTLV-1 causes insertional mutagenesis up to the megabase range in the host genome in >104 persistently-maintained HTLV-1+ T-cell clones in vivo.
Menz F, Menz J, Wilson K, et al., 2018, Infective dermatitis associated with human T-lymphotropic virus type 1 infection in Adelaide, South Australia, Australasian Journal of Dermatology, Vol: 59, Pages: 151-153, ISSN: 0004-8380
Satou Y, Katsuya H, Fukuda A, et al., 2018, Dynamics and mechanisms of clonal expansion of HIV-1-infected cells in a humanized mouse model (vol 7, 6913, 2017), SCIENTIFIC REPORTS, Vol: 8, ISSN: 2045-2322
Kulkarni A, Bangham CRM, 2018, HTLV-1: Regulating the Balance Between Proviral Latency and Reactivation, FRONTIERS IN MICROBIOLOGY, Vol: 9, ISSN: 1664-302X
HTLV-1 plus-strand transcription begins with the production of doubly-spliced tax/rex transcripts, the levels of which are usually undetectable in freshly isolated peripheral blood mononuclear cells (PBMCs) from HTLV-1-infected individuals. However, the presence of a sustained chronically active cytotoxic T-cell response to HTLV-1 antigens in virtually all HTLV-1-infected individuals, regardless of their proviral load, argues against complete latency of the virus in vivo. There is an immediate burst of plus-strand transcription when blood from infected individuals is cultured ex vivo. How is the HTLV-1 plus strand silenced in PBMCs? Is it silenced in other anatomical compartments within the host? What reactivates the latent provirus in fresh PBMCs? While plus-strand transcription of the provirus appears to be intermittent, the minus-strand hbz transcripts are present in a majority of cells, albeit at low levels. What regulates the difference between the 5′- and 3′-LTR promoter activities and thereby the tax-hbz interplay? Finally, T lymphocytes are a migratory population of cells that encounter variable environments in different compartments of the body. Could these micro-environment changes influence the reactivation kinetics of the provirus? In this review we discuss the questions raised above, focusing on the early events leading to HTLV-1 reactivation from latency, and suggest future research directions.
Einsiedel L, Pham H, Wilson K, et al., 2018, Human T-Lymphotropic Virus type 1c subtype proviral loads, chronic lung disease and survival in a prospective cohort of Indigenous Australians, PLoS Neglected Tropical Diseases, Vol: 12, ISSN: 1935-2727
BackgroundThe Human T-Lymphotropic Virus type 1c subtype (HTLV-1c) is highly endemic to central Australia where the most frequent complication of HTLV-1 infection in Indigenous Australians is bronchiectasis. We carried out a prospective study to quantify the prognosis of HTLV-1c infection and chronic lung disease and the risk of death according to the HTLV-1c proviral load (pVL).Methodology/Principal findings840 Indigenous adults (discharge diagnosis of bronchiectasis, 154) were recruited to a hospital-based prospective cohort. Baseline HTLV-1c pVL were determined and the results of chest computed tomography and clinical details reviewed. The odds of an association between HTLV-1 infection and bronchiectasis or bronchitis/bronchiolitis were calculated, and the impact of HTLV-1c pVL on the risk of death was measured.Radiologically defined bronchiectasis and bronchitis/bronchiolitis were significantly more common among HTLV-1-infected subjects (adjusted odds ratio = 2.9; 95% CI, 2.0, 4.3). Median HTLV-1c pVL for subjects with airways inflammation was 16-fold higher than that of asymptomatic subjects. There were 151 deaths during 2,140 person-years of follow-up (maximum follow-up 8.13 years). Mortality rates were higher among subjects with HTLV-1c pVL ≥1000 copies per 105 peripheral blood leukocytes (log-rank χ2 (2df) = 6.63, p = 0.036) compared to those with lower HTLV-1c pVL or uninfected subjects. Excess mortality was largely due to bronchiectasis-related deaths (adjusted HR 4.31; 95% CI, 1.78, 10.42 versus uninfected).Conclusion/SignificanceHigher HTLV-1c pVL was strongly associated with radiologically defined airways inflammation and with death due to complications of bronchiectasis. An increased risk of death due to an HTLV-1 associated inflammatory disease has not been demonstrated previously. Our findings indicate that mortality associated with HTLV-1c infection may be higher than has been previously appreciated. Further prospective studies are needed to
Melamed A, Yaguchi H, Miura M, et al., 2018, The human leukemia virus HTLV-1 alters the structure and transcription of host chromatin <i>in cis</i>
<jats:title>Abstract</jats:title><jats:p>Chromatin looping controls gene expression by regulating promoter-enhancer contacts, the spread of epigenetic modifications, and the segregation of the genome into transcriptionally active and inactive compartments. We studied the impact on the structure and expression of host chromatin by the human retrovirus HTLV-1. We show that HTLV-1 disrupts host chromatin structure by forming loops between the provirus and the host genome; certain loops depend on the critical chromatin architectural protein CTCF, which we recently showed binds to the HTLV-1 provirus. Finally, we show that the provirus causes two distinct patterns of abnormal transcription of the host genome <jats:italic>in cis</jats:italic>: bidirectional transcription in the host genome immediately flanking the provirus, and clone-specific transcription <jats:italic>in cis</jats:italic> at non-contiguous loci up to >300 kb from the integration site. We conclude that HTLV-1 causes insertional mutagenesis up to the megabase range in the host genome in >10<jats:sup>4</jats:sup> persistently-maintained HTLV-1<jats:sup>+</jats:sup> T-cell clones in vivo.</jats:p>
Bangham CRM, 2018, Human T Cell Leukemia Virus Type 1: Persistence and Pathogenesis, ANNUAL REVIEW OF IMMUNOLOGY, VOL 36, Vol: 36, Pages: 43-71, ISSN: 0732-0582
Billman MR, Rueda D, Bangham CRM, 2017, Single-cell heterogeneity and cell-cycle-related viral gene bursts in the human leukaemia virus HTLV-1 [version 2; peer review: 2 approved, 1 approved with reservations], Wellcome Open Research, Vol: 2, ISSN: 2398-502X
Background: The human leukaemia virus HTLV-1 expresses essential accessory genes that manipulate the expression, splicing and transport of viral mRNAs. Two of these genes, tax and hbz, also promote proliferation of the infected cell, and both genes are thought to contribute to oncogenesis in adult T-cell leukaemia/lymphoma. The regulation of HTLV-1 proviral latency is not understood. tax, on the proviral plus strand, is usually silent in freshly-isolated cells, whereas the minus-strand-encoded hbz gene is persistently expressed at a low level. However, the persistently activated host immune response to Tax indicates frequent expression of tax in vivo. Methods: We used single-molecule RNA-FISH to quantify the expression of HTLV-1 transcripts at the single-cell level in a total of >19,000 cells from five T-cell clones, naturally infected with HTLV-1, isolated by limiting dilution from peripheral blood of HTLV-1-infected subjects. Results: We found strong heterogeneity both within and between clones in the expression of the proviral plus-strand (detected by hybridization to the tax gene) and the minus-strand (hbz gene). Both genes are transcribed in bursts; tax expression is enhanced in the absence of hbz, while hbz expression increased in cells with high tax expression. Surprisingly, we found that hbz expression is strongly associated with the S and G 2/M phases of the cell cycle, independent of tax expression. Contrary to current belief, hbz is not expressed in all cells at all times, even within one clone. In hbz-positive cells, the abundance of hbz transcripts showed a very strong positive linear correlation with nuclear volume.Conclusions: The occurrence of intense, intermittent plus-strand gene bursts in independent primary HTLV-1-infected T-cell clones from unrelated individuals strongly suggests that the HTLV-1 plus-strand is expressed in bursts in vivo. Our results offer an explanation for the paradoxical correlations observed between the host immune
Furuta R, Yasunaga J-I, Miura M, et al., 2017, Human T-cell leukemia virus type 1 infects multiple lineage hematopoietic cells in vivo., PLoS Pathogens, Vol: 13, ISSN: 1553-7366
Human T-cell leukemia virus type 1 (HTLV-1) infects mainly CD4+CCR4+ effector/memory T cells in vivo. However, it remains unknown whether HTLV-1 preferentially infects these T cells or this virus converts infected precursor cells to specialized T cells. Expression of viral genes in vivo is critical to study viral replication and proliferation of infected cells. Therefore, we first analyzed viral gene expression in non-human primates naturally infected with simian T-cell leukemia virus type 1 (STLV-1), whose virological attributes closely resemble those of HTLV-1. Although the tax transcript was detected only in certain tissues, Tax expression was much higher in the bone marrow, indicating the possibility of de novo infection. Furthermore, Tax expression of non-T cells was suspected in bone marrow. These data suggest that HTLV-1 infects hematopoietic cells in the bone marrow. To explore the possibility that HTLV-1 infects hematopoietic stem cells (HSCs), we analyzed integration sites of HTLV-1 provirus in various lineages of hematopoietic cells in patients with HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP) and a HTLV-1 carrier using the high-throughput sequencing method. Identical integration sites were detected in neutrophils, monocytes, B cells, CD8+ T cells and CD4+ T cells, indicating that HTLV-1 infects HSCs in vivo. We also detected Tax protein in myeloperoxidase positive neutrophils. Furthermore, dendritic cells differentiated from HTLV-1 infected monocytes caused de novo infection to T cells, indicating that infected monocytes are implicated in viral spreading in vivo. Certain integration sites were re-detected in neutrophils from HAM/TSP patients at different time points, indicating that infected HSCs persist and differentiate in vivo. This study demonstrates that HTLV-1 infects HSCs, and infected stem cells differentiate into diverse cell lineages. These data indicate that infection of HSCs can contribute to the persistence and spread
Cook LB, Rowan A, Demontis M, et al., 2017, Long-term clinical remission maintained after cessation of zidovudine and interferon-α therapy in chronic adult T-cell leukemia/lymphoma, International Journal of Hematology, Vol: 107, Pages: 378-382, ISSN: 0925-5710
Globally, > 5–10 million people are estimated to be infected with Human T-lymphotropic virus type 1 (HTLV-1), of whom ~ 5% develop adult T-cell leukemia/lymphoma (ATL). Despite advances in chemotherapy, overall survival (OS) has not improved in the 35 years since HTLV-1 was first described. In Europe/USA, combination treatment with zidovudine and interferon-α (ZDV/IFN-α) has substantially changed the management of patients with the leukemic subtypes of ATL (acute or unfavorable chronic ATL) and is under clinical trial evaluation in Japan. However, there is only a single published report of long-term clinical remission on discontinuing ZDV/IFN-α therapy and the optimal duration of treatment is unknown. Anecdotal cases where therapy is discontinued due to side effects or compliance have been associated with rapid disease relapse, and it has been widely accepted that the majority of patients will require life-long therapy. The development of molecular methods to quantify minimal residual disease is essential to potentially guide therapy for individual patients. Here, for the first time, we report molecular evidence that supports long-term clinical remission in a patient who was previously treated with ZDV/IFN-α for 5 years, and who has now been off all therapy for over 6 years.
Bangham CRM, Matsuoka M, 2017, Human T-cell leukaemia virus type 1: parasitism and pathogenesis, PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES, Vol: 372, ISSN: 0962-8436
Human T-cell leukaemia virus type 1 (HTLV-1) causes not only adult T-cell leukaemia-lymphoma (ATL), but also inflammatory diseases including HTLV-1-associated myelopathy/tropical spastic paraparesis. HTLV-1 transmits primarily through cell-to-cell contact, and generates abundant infected cells in the host in order to survive and transmit to a new host. The resulting high proviral load is closely associated with the development of ATL and inflammatory diseases. To increase the number of infected cells, HTLV-1 changes the immunophenotype of infected cells, induces proliferation and inhibits apoptosis through the cooperative actions of two viral genes, tax and HTLV-1 bZIP factor (HBZ). As a result, infected cells survive, proliferate and infiltrate into the tissues, which is critical for transmission of the virus. Thus, the strategy of this virus is indivisibly linked with its pathogenesis, providing a clue for prevention and treatment of HTLV-1-induced diseases.
Kulkarni A, Mateus M, Thinnes CC, et al., 2017, Glucose metabolism and oxygen availability govern reactivation from latency of the human retrovirus HTLV-1, Cell Chemical Biology, Vol: 24, Pages: 1377-1387.e3, ISSN: 2451-9456
The human retrovirus HTLV-1 causes a hematological malignancy or neuroinflammatory disease in ∼10% of infected individuals. HTLV-1 primarily infects CD4+ T lymphocytes and persists as a provirus integrated in their genome. HTLV-1 appears transcriptionally latent in freshly isolated cells; however, the chronically active anti-HTLV-1 cytotoxic T cell response observed in infected individuals indicates frequent proviral expression in vivo. The kinetics and regulation of HTLV-1 proviral expression in vivo are poorly understood. By using hypoxia, small-molecule hypoxia mimics, and inhibitors of specific metabolic pathways, we show that physiologically relevant levels of hypoxia, as routinely encountered by circulating T cells in the lymphoid organs and bone marrow, significantly enhance HTLV-1 reactivation from latency. Furthermore, culturing naturally infected CD4+ T cells in glucose-free medium or chemical inhibition of glycolysis or the mitochondrial electron transport chain strongly suppresses HTLV-1 plus-strand transcription. We conclude that glucose metabolism and oxygen tension regulate HTLV-1 proviral latency and reactivation in vivo.
Billman MR, Rueda D, Bangham CRM, 2017, Single-cell heterogeneity and cell-cycle-related viral gene bursts in the human leukaemia virus HTLV-1 [version 1; peer review: 2 approved, 1 approved with reservations], Wellcome Open Research, Vol: 2, Pages: 87-87, ISSN: 2398-502X
Background: The human leukaemia virus HTLV-1 expresses essential accessory genes that manipulate the expression, splicing and transport of viral mRNAs. Two of these genes, tax and hbz, also promote proliferation of the infected cell, and both genes are thought to contribute to oncogenesis in adult T-cell leukaemia/lymphoma. The regulation of HTLV-1 proviral latency is not understood. tax, on the proviral plus strand, is usually silent in freshly-isolated cells, whereas the minus-strand-encoded hbz gene is persistently expressed at a low level. However, the persistently activated host immune response to Tax indicates frequent expression of tax in vivo. Methods: We used single-molecule RNA-FISH to quantify the expression of HTLV-1 transcripts at the single-cell level in a total of >19,000 cells from five T-cell clones, naturally infected with HTLV-1, isolated by limiting dilution from peripheral blood of HTLV-1-infected subjects. Results: We found strong heterogeneity both within and between clones in the expression of the proviral plus-strand (detected by hybridization to the tax gene) and the minus-strand ( hbz gene). Both genes are transcribed in bursts; tax expression is enhanced in the absence of hbz, while hbz expression increased in cells with high tax expression. Surprisingly, we found that hbz expression is strongly associated with the S and G 2/M phases of the cell cycle, independent of tax expression. Contrary to current belief, hbz is not expressed in all cells at all times, even within one clone. In hbz-positive cells, the abundance of hbz transcripts showed a very strong positive linear correlation with nuclear volume. Conclusions: The occurrence of intense, intermittent plus-strand gene bursts in independent primary HTLV-1-infected T-cell clones from unrelated individuals strongly suggests that the HTLV-1 plus-strand is expressed in bursts in vivo. Our results offer an explanat
Cook L, Melamed A, Yaguchi H, et al., 2017, The impact of HTLV-1 on the cellular genome., Current Opinion in Virology, Vol: 26, Pages: 125-131, ISSN: 1879-6265
Human T-lymphotropic virus type-1 (HTLV-1) is the causative agent of adult T-cell leukaemia/lymphoma (ATL), an aggressive CD4+ T-cell malignancy. The mechanisms of leukaemogenesis in ATL are incompletely understood. Insertional mutagenesis has not previously been thought to contribute to the pathogenesis of ATL. However, the recent discovery that HTLV-1 binds the key chromatin architectural protein CTCF raises the hypothesis that HTLV-1 deregulates host gene expression by causing abnormal chromatin looping, bringing the strong HTLV-1 promoter-enhancer near to host genes that lie up to 2Mb from the integrated provirus. Here we review current opinion on the mechanisms of oncogenesis in ATL, with particular emphasis on the local and distant impact of HTLV-1 on the structure and expression of the host genome.
Satou Y, Katsuya H, Fukuda A, et al., 2017, Dynamics and mechanisms of clonal expansion of HIV-1-infected cells in a humanized mouse model., Scientific Reports, Vol: 7, ISSN: 2045-2322
Combination anti-retroviral therapy (cART) has drastically improved the clinical outcome of HIV-1 infection. Nonetheless, despite effective cART, HIV-1 persists indefinitely in infected individuals. Clonal expansion of HIV-1-infected cells in peripheral blood has been reported recently. cART is effective in stopping the retroviral replication cycle, but not in inhibiting clonal expansion of the infected host cells. Thus, the proliferation of HIV-1-infected cells may play a role in viral persistence, but little is known about the kinetics of the generation, the tissue distribution or the underlying mechanism of clonal expansion in vivo. Here we analyzed the clonality of HIV-1-infected cells using high-throughput integration site analysis in a hematopoietic stem cell-transplanted humanized mouse model. Clonally expanded, HIV-1-infected cells were detectable at two weeks post infection, their abundance increased with time, and certain clones were present in multiple organs. Expansion of HIV-1-infected clones was significantly more frequent when the provirus was integrated near host genes in specific gene ontological classes, including cell activation and chromatin regulation. These results identify potential drivers of clonal expansion of HIV-1-infected cells in vivo.
Zhyvoloup A, Melamed A, Anderson I, et al., 2017, Digoxin reveals a functional connection between HIV-1 integration preference and T-cell activation, PLOS PATHOGENS, Vol: 13, ISSN: 1553-7366
HIV-1 integrates more frequently into transcribed genes, however the biological significance of HIV-1 integration targeting has remained elusive. Using a selective high-throughput chemical screen, we discovered that the cardiac glycoside digoxin inhibits wild-type HIV-1 infection more potently than HIV-1 bearing a single point mutation (N74D) in the capsid protein. We confirmed that digoxin repressed viral gene expression by targeting the cellular Na+/K+ ATPase, but this did not explain its selectivity. Parallel RNAseq and integration mapping in infected cells demonstrated that digoxin inhibited expression of genes involved in T-cell activation and cell metabolism. Analysis of >400,000 unique integration sites showed that WT virus integrated more frequently than N74D mutant within or near genes susceptible to repression by digoxin and involved in T-cell activation and cell metabolism. Two main gene networks down-regulated by the drug were CD40L and CD38. Blocking CD40L by neutralizing antibodies selectively inhibited WT virus infection, phenocopying digoxin. Thus the selectivity of digoxin depends on a combination of integration targeting and repression of specific gene networks. The drug unmasked a functional connection between HIV-1 integration and T-cell activation. Our results suggest that HIV-1 evolved integration site selection to couple its early gene expression with the status of target CD4+ T-cells, which may affect latency and viral reactivation.
Macchi B, Balestrieri E, Frezza C, et al., 2017, Quantification of HTLV-1 reverse transcriptase activity in ATL patients treated with zidovudine and interferon-α, Blood Advances, Vol: 1, Pages: 748-752, ISSN: 2473-9529
Bangham CRM, Gillet N, Melamed A, 2017, High-throughput mapping and clonal quantification of retroviral integration sites, Methods in Molecular Biology
Oksenhendler E, Turpin J, Lhote R, et al., 2017, Persistent risk of adult T-cell leukemia/lymphoma after neonatal HTLV-1 infection through exchange transfusion, INTERNATIONAL JOURNAL OF HEMATOLOGY, Vol: 105, Pages: 859-862, ISSN: 0925-5710
A 36-year-old Caucasian male presented with adult T-cell leukemia/lymphoma (ATL). HTLV-1 contamination was attributed to a neonatal exchange transfusion. Remission was achieved but 11 years later he presented with symptoms suggesting ATL relapse. Molecular studies of T-cell clonality and virus integration sites revealed a clonal disease, distinct from the first tumor.
Kagdi HH, taylor GPT, DEMONTIS MA, et al., 2016, Risk stratification of adult T cell leukemia/lymphoma using immunophenotyping, Cancer Medicine, Vol: 6, Pages: 298-309, ISSN: 2045-7634
Adult T cell leukemia/lymphoma (ATL), a human T lymphotropic virus type 1 (HTLV-1) –associated disease, has a highly variable clinical course and four subtypes with therapeutic and prognostic implications. However, there are overlapping features between ATL subtypes and between ATL and non-malignant (non-ATL) HTLV-1 infection complicating diagnosis and prognostication. To further refine the diagnosis and prognosis of ATL we characterized the immunophenotype of HTLV-1-infected cells in ATL and non-ATL. A retrospective study of peripheral blood samples from ten HTLV-1-uninfected subjects (UI), 54 HTLV-1infected patients with non-ATL and 22 with ATL was performed using flow cytometry. All patients with ATL had CD4+CCR4+CD26- immunophenotype and the frequency of CD4+CCR4+CD26- T cells correlated highly significantly with the proviral load in non-ATL suggesting CD4+CCR4+CD26- as a marker of HTLV-1 infected cells. Further immunophenotyping of CD4+CCR4+CD26- cells revealed that 95% patients with ATL had a CD7- (≤ 30% CD7+ cells) whereas 95% HTLV+ non-ATL had CD7+ (>30% CD7+ cells) immunophenotype. All patients with aggressive ATL had a CCR7+ (≥30%), whereas 92 % with indolent ATL and 100% non-ATL had a CCR7- (<30%) immunophenotype. Patients with non-progressing indolent ATL were CD127+ but those with progressive lymphocytosis requiring systemic therapy had a CD127- (≤ 30%) immunophenotype. In summary, HTLV-1-infected cells have a CD4+CCR4+CD26- immunophenotype. Within this population, CD7- phenotype suggests a diagnosis of ATL, CCR7+ phenotype identifies aggressive ATL, while CCR7- CD127- phenotype identifies progressive indolent ATL.
Gallo RC, Willems L, Hasegawa H, et al., 2016, Screening transplant donors for HTLV-1 and -2, Blood, Vol: 128, Pages: 3029-3031, ISSN: 1528-0020
Human T-cell leukemia virus-1 (HTLV-1) is the first pathogenic human retrovirus discovered in 1980.1 HTLV-1 causes 2 devastating diseases: adult T-cell leukemia/lymphoma (ATL) and a neurological disorder, HTLV-1–associated myelopathy/tropical spastic paraparesis (HAM/TSP or, more briefly, HAM). ATL becomes apparent in 2% to 5% of those infected with HTLV-1; another 1% to 2% will develop HAM.2 There are usually 2 to 3 decades of latency after the infection before the onset of symptoms. A second HTLV (HTLV-2) isolated in 1982 has been causally linked to HAM, but not ATL.3In other cases, HTLV-1 and HTLV-2 infection may remain asymptomatic for years while being transmitted from person-to-person through host cells in body fluids and breast milk, blood cell transfusions, and solid organ transplantation. There are no licensed vaccines to prevent HTLV-1 or HTLV-2 infections.
Turpin J, Alais S, Marcais A, et al., 2016, Whole body clonality analysis in an aggressive STLV-1 associated leukemia (ATLL) reveals an unexpected clonal complexity, CANCER LETTERS, Vol: 389, Pages: 78-85, ISSN: 0304-3835
HTLV-1 causes Adult T cell Leukemia/Lymphoma (ATLL) in humans. We describe an ATL-like disease in a 9 year-old female baboon naturally infected with STLV-1 (the simian counterpart of HTLV-1), with a lymphocyte count over 1010/L, lymphocytes with abnormal nuclear morphology, and pulmonary and skin lesions. The animal was treated with a combination of AZT and alpha interferon. Proviral load (PVL) was measured every week. Because the disease continued to progress, the animal was euthanized. Abnormal infiltrates of CD3+CD25+ lymphocytes and Tax-positive cells were found by histological analyses in both lymphoid and non-lymphoid organs. PVL was measured and clonal diversity was assessed by LM-PCR (Ligation-Mediated Polymerase Chain Reaction) and high throughput sequencing, in blood during treatment and in 14 different organs. The highest PVL was found in lymph nodes, spleen and lungs. One major clone and a number of intermediate abundance clones were present in blood throughout the course of treatment, and in organs. These results represent the first multi-organ clonality study in ATLL. We demonstrate a previously undescribed clonal complexity in ATLL. Our data reinforce the usefulness of natural STLV-1 infection as a model of ATLL.
Rowan A, Witkover A, Melamed A, et al., 2016, T cell receptor Vβ staining identifies the malignant clone in adult T cell leukemia and reveals killing of leukemia cells by autologous CD8+ T cells, Plos Pathogens, Vol: 12, ISSN: 1553-7374
There is growing evidence that CD8+ cytotoxic T lymphocyte (CTL) responses can contribute to long-term remission of many malignancies. The etiological agent of adult T-cell leukemia/lymphoma (ATL), human T lymphotropic virus type-1 (HTLV-1), contains highly immunogenic CTL epitopes, but ATL patients typically have low frequencies of cytokine-producing HTLV-1-specific CD8+ cells in the circulation. It remains unclear whether patients with ATL possess CTLs that can kill the malignant HTLV-1 infected clone. Here we used flow cytometric staining of TCRVβ and cell adhesion molecule-1 (CADM1) to identify monoclonal populations of HTLV-1-infected T cells in the peripheral blood of patients with ATL. Thus, we quantified the rate of CD8+-mediated killing of the putative malignant clone in ex vivo blood samples. We observed that CD8+ cells from ATL patients were unable to lyse autologous ATL clones when tested directly ex vivo. However, short in vitro culture restored the ability of CD8+ cells to kill ex vivo ATL clones in some donors. The capacity of CD8+ cells to lyse HTLV-1 infected cells which expressed the viral sense strand gene products was significantly enhanced after in vitro culture, and donors with an ATL clone that expressed the HTLV-1 Tax gene were most likely to make a detectable lytic CD8+ response to the ATL cells. We conclude that some patients with ATL possess functional tumour-specific CTLs which could be exploited to contribute to control of the disease.
Lewin A, Hamilton S, Witkover A, et al., 2016, Free serum haemoglobin is associated with brain atrophy in secondary progressive multiple sclerosis [version 1; peer review: 1 approved, 2 approved with reservations], Wellcome Open Research, Vol: 1, ISSN: 2398-502X
Background A major cause of disability in secondary progressive multiple sclerosis (SPMS) is progressive brain atrophy, whose pathogenesis is not fully understood. The objective of this study was to identify protein biomarkers of brain atrophy in SPMS. Methods We used surface-enhanced laser desorption-ionization time-of-flight mass spectrometry to carry out an unbiased search for serum proteins whose concentration correlated with the rate of brain atrophy, measured by serial MRI scans over a 2-year period in a well-characterized cohort of 140 patients with SPMS. Protein species were identified by liquid chromatography-electrospray ionization tandem mass spectrometry. Results There was a significant (p<0.004) correlation between the rate of brain atrophy and a rise in the concentration of proteins at 15.1 kDa and 15.9 kDa in the serum. Tandem mass spectrometry identified these proteins as alpha-haemoglobin and beta-haemoglobin, respectively. The abnormal concentration of free serum haemoglobin was confirmed by ELISA (p<0.001). The serum lactate dehydrogenase activity was also highly significantly raised (p<10(-12)) in patients with secondary progressive multiple sclerosis. Conclusions An underlying low-grade chronic intravascular haemolysis is a potential source of the iron whose deposition along blood vessels in multiple sclerosis plaques contributes to the neurodegeneration and consequent brain atrophy seen in progressive disease. Chelators of free serum iron will be ineffective in preventing this neurodegeneration, because the iron (Fe(2+)) is chelated by haemoglobin.
Kirk PDW, Huvet M, Melamed A, et al., 2016, Retroviruses integrate into a shared, non-palindromic DNA motif, Nature Microbiology, Vol: 2, Pages: 1-6, ISSN: 2058-5276
Many DNA-binding factors, such as transcription factors, form oligomeric complexes with structural symmetry that bind to palindromic DNA sequences1. Palindromic consensus nucleotide sequences are also found at the genomic integration sites of retroviruses2,3,4,5,6 and other transposable elements7,8,9, and it has been suggested that this palindromic consensus arises as a consequence of the structural symmetry in the integrase complex2,3. However, we show here that the palindromic consensus sequence is not present in individual integration sites of human T-cell lymphotropic virus type 1 (HTLV-1) and human immunodeficiency virus type 1 (HIV-1), but arises in the population average as a consequence of the existence of a non-palindromic nucleotide motif that occurs in approximately equal proportions on the plus strand and the minus strand of the host genome. We develop a generally applicable algorithm to sort the individual integration site sequences into plus-strand and minus-strand subpopulations, and use this to identify the integration site nucleotide motifs of five retroviruses of different genera: HTLV-1, HIV-1, murine leukaemia virus (MLV), avian sarcoma leucosis virus (ASLV) and prototype foamy virus (PFV). The results reveal a non-palindromic motif that is shared between these retroviruses.
Willems L, Hasegawa H, Accolla R, et al., 2016, Reducing the global burden of HTLV-1 infection: an agenda for research and action, Antiviral Research, Vol: 137, Pages: 41-48, ISSN: 1872-9096
Even though an estimated 10-20 million people worldwide are infected with the oncogenic retrovirus, human T-lymphotropic virus type 1 (HTLV-1), its epidemiology is poorly understood, and little effort has been made to reduce its prevalence. In response to this situation, the Global Virus Network launched a taskforce in 2014 to develop new methods of prevention and treatment of HTLV-1 infection and promote basic research. HTLV-1 is the etiological agent of two life-threatening diseases, adult T-cell leukemia and HTLV-associated myelopathy/tropical spastic paraparesis, for which no effective therapy is currently available. Although the modes of transmission of HTLV-1 resemble those of the more familiar HIV-1, routine diagnostic methods are generally unavailable to support the prevention of new infections. In the present article, the Taskforce proposes a series of actions to expand epidemiological studies; increase research on mechanisms of HTLV-1 persistence, replication and pathogenesis; discover effective treatments; and develop prophylactic and therapeutic vaccines.
Zhyvoloup A, Melamed A, Anderson I, et al., 2016, A capsid-dependent integration program linking T cell activation to HIV-1 gene expression, Publisher: BIOMED CENTRAL LTD, ISSN: 1742-4690
Manivannan K, Rowan AG, Tanaka Y, et al., 2016, CADM1/TSLC1 identifies HTLV-1-infected cells and determines their susceptibility to CTL-mediated lysis, PLOS Pathogens, Vol: 12, ISSN: 1553-7366
Human T cell lymphotropic virus-1 (HTLV-1) primarily infects CD4+ T cells, causing inflammatory disorders or a T cell malignancy in 5% to 10% of carriers. The cytotoxic T lymphocyte (CTL) response is a key factor that controls the viral load and thus the risk of disease. The ability to detect the viral protein Tax in primary cells has made it possible to estimate the rate at which Tax-expressing infected cells are eliminated by CTLs in persistently infected people. However, most HTLV-1-infected cells are Tax–at a given time, and their immunophenotype is poorly defined. Here, we aimed to identify a cell-surface molecule expressed by both Tax+ and Tax–HTLV-1-infected cells and use it to analyse the CTL response in fresh peripheral blood mononuclear cells. Cell adhesion molecule 1 (CADM1/TSLC1) was the best single marker of HTLV-1 infection, identifying HTLV-1-infected cells with greater sensitivity and specificity than CD25, CCR4 or ICAM-1. CADM1+CD4+ T cells carried a median of 65% of proviral copies in peripheral blood. In a cohort of 23 individuals, we quantified the rate of CTL-mediated killing of Tax+ and Tax−CADM1+ cells. We show that CADM1 expression is associated with enhanced susceptibility of infected cells to CTL lysis: despite the immunodominance of Tax in the CTL response, Tax+CADM1– cells were inefficiently lysed by CTLs. Upregulation of the CADM1 ligand CRTAM on CD8+ T cells correlated with efficient lysis of infected cells. Tax–CADM1+ cells were lysed at a very low rate by autologous CTLs, however, were efficiently killed when loaded with exogenous peptide antigen. High expression of CADM1 on most HTLV-1-infected cells in the face of enhanced CTL counterselection implies that CADM1 confers a strong benefit on the virus.
Satou Y, Miyazato P, Ishihara Y, et al., 2016, The retrovirus HTLV-1 inserts an ectopic CTCF-binding site into the human genome, Proceedings of the National Academy of Sciences of the United States of America, Vol: 113, Pages: 3054-3059, ISSN: 0027-8424
Human T-lymphotropic virus type 1 (HTLV-1) is a retrovirus thatcauses malignant and inflammatory diseases in 10% of infectedpeople. A typical host has between 104and 105clones of HTLV-1-infected T lymphocytes, each clone distinguished by the genomicintegration site of the single-copy HTLV-1 provirus. TheHBZgeneis constitutively expressed from the minus strand of the provirus,whereas plus-strand expression, required for viral propagation touninfected cells, is suppressed or intermittentin vivo, allowingescape from host immune surveillance. It remains unknown whatregulates this pattern of proviral transcription and latency. Herewe show that CTCF, a key regulator of chromatin structure andfunction, binds to the provirus at a sharp border in epigeneticmodifications in the pX region of the HTLV-1 provirus, in T cellsnaturally infected with HTLV-1. CTCF is a zinc-finger protein thatbinds to an insulator region in genomic DNA and plays a funda-mental role in controlling higher-order chromatin structure andgene expression in vertebrate cells. We show that CTCF boundto HTLV-1 acts as an enhancer blocker, regulates HTLV-1 mRNAsplicing, and forms long-distance interactions with flanking hostchromatin. CTCF binding sites have been propagated through-out the genome by transposons in certain primate lineages, butCTCF binding has not previously been described in present-dayexogenous retroviruses. The presence of an ectopic CTCF bindingsite introduced by the retrovirus in tens of thousands of genomiclocations has the potential to cause widespread abnormalities inhost cell chromatin structure and gene expression.
Kostic M, Crews CM, Hertweck C, et al., 2016, Cell Chemical Biology: Home of Exciting Chemical Biology, Cell Chemical Biology, Vol: 23, Pages: 1-2, ISSN: 2451-9456
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