Kagoshima-shi, Japan
Kagoshima-shi, Japan

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Satou Y.,Kyoto University | Satou Y.,Imperial College London | Utsunomiya A.,Imamura Bun in Hospital | Tanabe J.,Kyoto University | And 3 more authors.
Retrovirology | Year: 2012

Background: HTLV-1 utilizes CD4 T cells as the main host cell and maintains the proviral load via clonal proliferation of infected CD4+ T cells. Infection of CD4+ T cells by HTLV-1 is therefore thought to play a pivotal role in HTLV-1-related pathogenicity, including leukemia/lymphoma of CD4+ T cells and chronic inflammatory diseases. Recently, it has been reported that a proportion of HTLV-1 infected CD4+ T cells express FoxP3, a master molecule of regulatory T cells. However, crucial questions remain unanswered on the relationship between HTLV-1 infection and FoxP3 expression.Results: To investigate the effect of HTLV-1 infection on CD4+ T-cell subsets, we used flow cytometry to analyze the T-cell phenotype and HTLV-1 infection in peripheral mononuclear cells (PBMCs) of four groups of subjects, including 23 HTLV-1-infected asymptomatic carriers (AC), 10 patients with HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP), 10 patients with adult T-cell leukemia (ATL), and 10 healthy donors. The frequency of FoxP3+ cells in CD4+ T cells in AC with high proviral load and patients with HAM/TSP or ATL was higher than that in uninfected individuals. The proviral load was positively correlated with the percentage of CD4+ T cells that were FoxP3+. The CD4+FoxP3+ T cells, themselves, were frequently infected with HTLV-1. We conclude that FoxP3+ T- cells are disproportionately infected with HTLV-1 during chronic infection. We next focused on PBMCs of HAM/TSP patients. The expression levels of the Treg associated molecules CTLA-4 and GITR were decreased in CD4+FoxP3+ T cells. Further we characterized FoxP3+CD4+ T-cell subsets by staining CD45RA and FoxP3, which revealed an increase in CD45RA-FoxP3low non-suppressive T-cells. These findings can reconcile the inflammatory phenotype of HAM/TSP with the observed increase in frequency of FoxP3+ cells. Finally, we analyzed ATL cells and observed not only a high frequency of FoxP3 expression but also wide variation in FoxP3 expression level among individual cases.Conclusions: HTLV-1 infection induces an abnormal frequency and phenotype of FoxP3+CD4+ T cells. © 2012 Satou et al.; licensee BioMed Central Ltd.

Sugata K.,Kyoto University | Satou Y.,Kyoto University | Yasunaga J.-I.,Kyoto University | Hara H.,Kyoto University | And 4 more authors.
Blood | Year: 2012

Adult T-cell leukemia (ATL) patients and human T-cell leukemia virus-1 (HTLV-1) infected individuals succumb to opportunistic infections. Cell mediated immunity is impaired, yet the mechanism of this impairment has remained elusive. The HTLV-1 basic leucine zipper factor (HBZ) gene is encoded in the minus strand of the viral DNA and is constitutively expressed in infected cells andATL cells. To test the hypothesis that HBZ contributes to HTLV-1-associated immunodeficiency, we challenged transgenic mice that express the HBZ gene in CD4 T cells (HBZ-Tg mice) with herpes simplex virus type 2 or Listeria monocytogenes, and evaluated cellular immunity to these pathogens. HBZ-Tg mice were more vulnerable to both infections than non-Tg mice. The acquired immune response phase was specifically suppressed, indicating that cellular immunity was impaired in HBZ-Tg mice. In particular, production of IFN-γ by CD4 T cells was suppressed in HBZ-Tg mice. HBZ suppressed transcription from the IFN-γ gene promoter in a CD4 T cell-intrinsic manner by inhibiting nuclear factor of activated T cells and the activator protein 1 signaling pathway. This study shows that HBZ inhibits CD4 T-cell responses by directly interfering with the host cell-signaling pathway, resulting in impaired cell-mediated immunity in vivo. © 2012 by The American Society of Hematology.

Utsunomiya A.,Imamura Bun in Hospital | Choi I.,National Kyushu Cancer Center | Chihara D.,Aichi Cancer Center Research Institute | Seto M.,Kurume University | Seto M.,Immuno Biological Laboratories
Cancer Science | Year: 2015

Recent advances in treatment for adult T-cell leukemia-lymphoma (ATL) are reviewed herein. It is currently possible to select a therapeutic strategy for ATL and predict prognosis by classification of patients by clinical subtypes and clinicopathological factors. Although the overall survival (OS) of patients with ATL has increased marginally because of advances in chemotherapy, further prolongation of survival might be difficult with conventional chemotherapy alone. Promising results have been reported for antiviral therapy using zidovudine and interferon-α, and, indeed, antiviral therapy is currently the standard treatment for patients with ATL in western countries. Remarkably, the 5-year OS rates are 100% for both the smoldering-type and chronic-type ATL. Recently, treatments for ATL have included allogeneic hematopoietic stem cell transplantation and molecular targeted therapies. Furthermore, the anti-CCR4 monoclonal antibody mogamulizumab has been shown to have marked cytotoxic effects on ATL cells, especially in the leukemic type of ATL. In the lymphoma type of ATL, the response rate may be improved by combining mogamulizumab with chemotherapy. It should be recognized that prevention of infection from carriers of human T-cell leukemia virus type-I and transfer of the virus from mother to infant are crucial issues for the eradication of ATL. © 2015 The Authors. Cancer Science published by Wiley Publishing Asia Pty Ltd on behalf of Japanese Cancer Association.

Kurosawa N.,University of Toyama | Fujimoto R.,Kochi Medical School | Ozawa T.,University of Toyama | Itoyama T.,Imamura Bun in Hospital | And 2 more authors.
PLoS ONE | Year: 2013

Background: Adult T-cell leukemia/lymphoma (ATLL) develops in a small proportion of human T-cell leukemia virus type I (HTLV-I)-infected individuals. However, the mechanism by which HTLV-I causes ATLL has not been fully elucidated. To provide fundamental insights into the multistep process of leukemogenesis, we have mapped the chromosomal abnormalities in 50 ATLL cases to identify potential key regulators of ATLL. Results: The analysis of breakpoints in one ATLL case with the translocations t(14;17)(q32;q22-23) resulted in the identification of a Kruppel zinc finger gene, BCL11B, which plays a crucial role in T-cell development. Among the 7 ATLL cases that we examined by immunofluorescence analysis, 4 displayed low and one displayed moderate BCL11B signal intensities. A dramatically reduced level of the BCL11B protein was also found in HTLV-I-positive T-cell lines. The ectopic expression of BCL11B resulted in significant growth suppression in ATLL-derived cell lines but not in Jurkat cells. Conclusions: Our genetic and functional data provide the first evidence that a reduction in the level of the BCL11B protein is a key event in the multistep progression of ATLL leukemogenesis. © 2013 Kurosawa et al.

Nishikawa H.,Osaka University | Maeda Y.,Osaka University | Ishida T.,Nagoya City University | Gnjatic S.,Sloan Kettering Cancer Center | And 11 more authors.
Blood | Year: 2012

Adult T-cell leukemia/lymphoma (ATLL) is an intractable hematologic malignancy caused by human T-lymphotropic virus type 1 (HTLV-1), which infects approximately 20 million people worldwide. Here, we have explored the possible expression of cancer/testis (CT) antigens by ATLL cells, as CT antigens are widely recognized as ideal targets of cancer immunotherapy against solid tumors. A high percentage (87.7%) of ATLL cases (n = 57) expressed CT antigens at the mRNA level: NY-ESO-1 (61.4%), MAGE-A3 (31.6%), and MAGE-A4 (61.4%). CT antigen expression was confirmed by immunohistochemistry. This contrasts with other types of lymphoma or leukemia, which scarcely express these CT antigens. Humoral immune responses, particularly against NY-ESO-1, were detected in 11.6% (5 of 43) and NY-ESO-1-specific CD8+ T-cell responses were observed in 55.6% (5 of 9) of ATLL patients. NY-ESO-1-specific CD8+T cells recognized autologous ATLL cells and produced effector cytokines. Thus, ATLL cells characteristically express CT antigens and therefore vaccination with CT antigens can be an effective immunotherapy of ATLL. © 2012 by The American Society of Hematology.

Kinpara S.,Tokyo Medical and Dental University | Kinpara S.,Japan Society for the Promotion of Science | Kijiyama M.,Tokyo Medical and Dental University | Takamori A.,Tokyo Medical and Dental University | And 6 more authors.
Retrovirology | Year: 2013

Background: Human T-cell leukemia virus type-1 (HTLV-1) is the causative retrovirus of adult T-cell leukemia/lymphoma (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). HTLV-1 gene expression is maintained at low levels in vivo by unknown mechanisms. A combination therapy of interferon-α (IFN-α) and zidovudin (AZT) shows therapeutic effects in ATL patients, although its mechanism is also obscure. We previously found that viral gene expression in IL-2-dependent HTLV-1-infected T-cells (ILTs) derived from ATL patients was markedly suppressed by stromal cells through a type I IFN response. Here, we investigated the effects of IFN-α with or without AZT on viral gene expression and cell growth in ILTs.Results: ILTs expressed variable but lower amounts of HTLV-1 Tax protein than HTLV-1-transformed HUT102 cells. Following the addition of IFN-α, the amounts of HTLV-1 p19 in the supernatants of these cells decreased in three days, while HTLV-1 gene expression decreased only in ILTs but not HUT102 cells. IFN-α also suppressed the spontaneous HTLV-1 induction in primary ATL cells cultured for 24 h. A time course study using ILTs revealed that the levels of intracellular Tax proteins decreased in the first 24 h after addition of IFN-α, before the reduction in HTLV-1 mRNA levels. The initial decreases of Tax protein following IFN-α treatment were observed in 6 of 7 ILT lines tested, although the reduction rates varied among ILT lines. An RNA-dependent protein kinase (PKR)-inhibitor reversed IFN-mediated suppression of Tax in ILTs. IFN-α also induced cell cycle arrest at the G0/G1 phase and suppressed NF-κB activities in these cells. AZT alone did not affect HTLV-1 gene expression, cell viability or NF-κB activities. AZT combined with IFN-α markedly induced cell apoptosis associated with phosphorylation of p53 and induction of p53-responsive genes in ILTs.Conclusions: IFN-α suppressed HTLV-1 gene expression at least through a PKR-mediated mechanism, and also induced cell cycle arrest in ILTs. In combination with AZT, IFN-α further induced p53 signaling and cell apoptosis in these cells. These findings suggest that HTLV-1-infected cells at an IL-2-dependent stage retain susceptibility to type I IFN-mediated regulation of viral expression, and partly explain how AZT/IFN-α produces therapeutic effects in ATL. © 2013 Kinpara et al.; licensee BioMed Central Ltd.

Umino A.,Aichi Cancer Center Research Institute | Umino A.,Mie University | Nakagawa M.,Aichi Cancer Center Research Institute | Utsunomiya A.,Imamura Bun in Hospital | And 5 more authors.
Blood | Year: 2011

Adult T-cell leukemia/lymphoma (ATLL) is the neoplasm caused by human T-cell leukemia virus type 1 (HTLV-1). We performed oligo-array comparative genomic hybridization (CGH) against paired samples comprising peripheral blood (PB) and lymph node (LN) samples from 13 patients with acute ATLL. We found that the genome profiles of the PB frequently differed from those of the LN samples. The results showed that 9 of 13 cases investigated had a log2 ratio imbalance among chromosomes, and that chromosome imbalances were more frequent in LN samples. Detailed analysis revealed that the imbalances were likely caused by the presence of multiple subclones in the LN samples. Five of 13 cases showed homozygous loss regions in PB samples, which were not found in the LN samples, indicating that tumors in the PB were derived from LN subclones in most cases. Southern blot analysis of TCRγ showed that these multiple subclones originated from a common clone. We concluded that in many ATLL cases, multiple subclones in the LNs originate from a common clone, and that a selected subclone among the LN subclones appears in the PB. © 2011 by The American Society of Hematology.

Ishii T.,Nagoya City University | Ishii T.,Kyowa Hakko Kirin Co | Ishida T.,Nagoya City University | Utsunomiya A.,Imamura Bun in Hospital | And 9 more authors.
Clinical Cancer Research | Year: 2010

Purpose: Adult T-cell leukemia/lymphoma (ATLL) has a very poor prognosis. We have developed the humanized defucosylated anti-CC chemokine receptor 4 (CCR4) monoclonal antibody KW-0761 as a next generation immunotherapeutic agent. The first aim of the present study was to evaluate whether the antitumor activity of KW-0761 would likely be sufficient for therapeutic clinical application against ATLL. The second aim was to fully elucidate the mechanism of antibody-dependent cellular cytotoxicity (ADCC) mediated by this defucosylated monoclonal antibody. Experimental Design: The antitumor activity of KW-0761 against ATLL cell lines was evaluated in vitro using human cells and in mice in vivo. Primary ATLL cells from 23 patients were evaluated for susceptibility to autologous ADCC with KW-0761 by two independent methods. Results: KW-0761 showed potent antitumor activity against ATLL cell lines both in vitro and in the ATLL mouse model in vivo. In addition, KW-0761 showed potent antitumor activity mediated by highly enhanced ADCC against primary ATLL cells both in vitro and ex vivo in an autologous setting. The degree of KW-0761 ADCC against primary ATLL cells in an autologous setting was mainly determined by the amount of effector natural killer cells present, but not the amount of the target molecule CCR4 on the ATLL cell surface. Conclusion: KW-0761 should be sufficiently active for therapeutic clinical application for ATLL. In addition, combination treatment strategies that augment natural killer cell activity should be promising for amplifying the effect of KW-0761. In the near future, the actual efficacy of KW-0761 will be established in pivotal clinical trials. ©2010 AACR.

Kannagi M.,Tokyo Medical and Dental University | Hasegawa A.,Tokyo Medical and Dental University | Kinpara S.,Tokyo Medical and Dental University | Shimizu Y.,Tokyo Medical and Dental University | And 2 more authors.
Cancer Science | Year: 2011

Human T-cell leukemia virus type 1 (HTLV-1) is the causative retrovirus of adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). HTLV-1-specific T-cell responses elicit antitumor and antiviral effects in experimental models, and are considered to be one of the most important determinants of the disease manifestation, since they are activated in HAM/TSP but not in ATL patients. The combination of low T-cell responses and elevated HTLV-1 proviral loads are features of ATL, and are also observed in a subpopulation of HTLV-1 carriers at the asymptomatic stage, suggesting that these features may be underlying risk factors. These risks may potentially be reduced by vaccination to activate HTLV-1-specific T-cell responses. HAM/TSP and ATL patients also differ in their levels of HTLV-1 mRNA expression, which are generally low in vivo but slightly higher in HAM/TSP patients. Our recent study indicated that viral expression in HTLV-1-infected T-cells is suppressed by stromal cells in culture through type-I IFNs. The suppression was reversible after isolation from the stromal cells, mimicking a long-standing puzzling phenomenon in HTLV-1 infection where the viral expression is very low in vivo and rapidly induced in vitro. Collectively, HTLV-1 is controlled by both acquired and innate immunity in vivo: HTLV-1-specific T-cells survey infected cells, and IFNs suppress viral expression. Both effects would contribute to a reduction in viral pathogenesis, although they may potentially influence or conflict with one another. The presence of double control systems for HTLV-1 infection provides a new concept for understanding the pathogenesis of HTLV-1-mediated malignant and inflammatory diseases. © 2011 Japanese Cancer Association.

Kannagi M.,Tokyo Medical and Dental University | Hasegawa A.,Tokyo Medical and Dental University | Takamori A.,Tokyo Medical and Dental University | Kinpara S.,Tokyo Medical and Dental University | Utsunomiya A.,Imamura Bun in Hospital
Frontiers in Microbiology | Year: 2012

Human T-cell leukemia virus type 1 (HTLV-1) causes adult T-cell leukemia (ATL) and HTLV1-associated myelopathy/tropical spastic paraparesis in small subsets of HTLV-1 carriers. HTLV-1-specific T-cell responses play critical roles in anti-viral and anti-tumor host defense during HTLV-1 infections. Some HTLV-1 carriers exhibit selective loss or anergy of HTLV-1specific T-cells at an asymptomatic stage. This is also observed in ATL patients and may therefore be an underlying risk factor of ATL in combination with elevated proviral loads. HTLV-1-specific T-cells often recognize the viral oncoprotein Tax, indicating expression of Tax protein in vivo, although levels of HTLV-1 gene expression are known to be very low. A type-I interferon (IFN) response can be induced by HTLV-1-infected cells and suppresses HTLV-1 expression in vitro, suggesting a role of type-I IFN response in viral suppression and pathogenesis in vivo. Both acquired and innate immune responses control the status of HTLV-1-infected cells and could be the important determinants in the development of HTLV-1-mediated malignant and inflammatory diseases. ©2012 Kannagi,Hasegawa, Takamori, Kinpara and Utsunomiya.© 2012 Kannagi,Hasegawa, Takamori, Kinpara and Utsunomiya.

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