Interleukin 1 gene expression in adult T cell leukemia.

The adult T cell leukemia (ATL) is a T cell neoplasm etiologically associated with human T lymphotropic virus type I (HTLV-I) infection. ATL cells often abnormally express interleukin 2 (IL-2) receptors, and ATL patients may show clinical evidence of hypercalcemia, osteolytic bone lesions, or increased bone turnover. Whereas interleukin 1 (IL-1) is not generally recognized as a product of T cells, this cytokine is capable of both altering IL-2 receptor expression and activating osteoclasts. Thus, we investigated the possibility that primary ATL leukemic T cells and HTLV-I-infected long-term ATL cell lines produce IL-1. S1 nuclease protection assays demonstrated that primary leukemic ATL cells from five out of six patients, as well as one patient with T4+ chronic lymphocytic leukemia, contained considerable quantities of IL-1 beta messenger RNA (mRNA) and small amounts of IL-1 alpha mRNA. These primary leukemic T cells also released biologically active IL-1 protein as evaluated in the murine thymocyte comitogenesis bioassay. In contrast to primary tumor cells, four out of six long-term ATL cell lines produced variable amounts of IL-1 alpha mRNA in the absence of detectable IL-1 beta mRNA as measured by S1 nuclease protection. These data demonstrate that IL-1 gene (especially IL-1 beta) expression occurs in many primary HTLV-I-infected leukemic T cells raising the possibility that this mediator may play a role in the pathological changes associated with this leukemia. Also, these studies show that the pattern of IL-1 alpha and IL-1 beta gene expression differs between primary ATL tumor cells and long-term cultured ATL cell lines, indicating an interesting biological difference in these two HTLV-I-infected cell populations.     

HTLV-1 infection promotes excessive T cell activation and transformation into adult T cell leukemia/lymphoma

Human T cell leukemia virus type 1 (HTLV-1) mainly infects CD4⁺ T cells and induces chronic, persistent infection in infected individuals, with some developing adult T cell leukemia/lymphoma (ATL). HTLV-1 alters cellular differentiation, activation, and survival; however, it is unknown whether and how these changes contribute to the malignant transformation of infected cells. In this study, we used single-cell RNA-sequencing and T cell receptor–sequencing to investigate the differentiation and HTLV-1–mediated transformation of T cells. We analyzed 87,742 PBMCs from 12 infected and 3 uninfected individuals. Using multiple independent bioinformatics methods, we demonstrated the seamless transition of naive T cells into activated T cells, whereby HTLV-1–infected cells in an activated state further transformed into ATL cells, which are characterized as clonally expanded, highly activated T cells. Notably, the greater the activation state of ATL cells, the more they acquire Treg signatures. Intriguingly, the expression of HLA class II genes in HTLV-1–infected cells was uniquely induced by the viral protein Tax and further upregulated in ATL cells. Functional assays revealed that HTLV-1–infected cells upregulated HLA class II molecules and acted as tolerogenic antigen-presenting cells to induce anergy of antigen-specific T cells. In conclusion, our study revealed the in vivo mechanisms of HTLV-1–mediated transformation and immune escape at the single-cell level.     

Transactivation of the transforming growth factor beta 1 (TGF-beta 1) gene by human T lymphotropic virus type 1 tax: a potential mechanism for the increased production of TGF-beta 1 in adult T cell leukemia

We examined the effect of the human T lymphotropic virus type 1 (HTLV-I) Tax gene product on the human transforming growth factor beta 1 (TGF-beta 1) promoter. Transfection of deleted constructs of the TGF-beta 1 promoter revealed regions homologous with AP-1 binding sites that were required for Tax-induced transactivation of the TGF-beta 1 promoter. In addition, we examined the expression and secretion of TGF-beta in fresh leukemic cells isolated from patients with adult T cell leukemia (ATL) and in HTLV-1-infected T cell lines. We report that fresh leukemic cells from ATL patients constitutively produce high levels of TGF-beta 1 mRNA and secrete TGF-beta 1 but not TGF-beta 2 into the culture medium. In addition, long-term ATL cell lines expressed significant amounts of TGF-beta 1 mRNA as well as detectable levels of TGF-beta 1 protein. These results suggest a role for Tax in the upregulation of TGF-beta 1 in HTLV-I-infected cells.     

Close association between interleukin 2 receptor mRNA expression and human T cell leukemia/lymphoma virus type I viral RNA expression in short-term cultured leukemic cells from adult T cell leukemia patients.

Human T cell leukemia/lymphoma (T-lymphotropic) virus type I (HTLV-I) infection has been considered to be closely associated with the leukemogenesis of adult T cell leukemia (ATL), in which interleukin 2 (IL-2) receptors are abnormally expressed. In this study, however, Southern blot analysis revealed no gross rearrangement or obvious amplification of the IL-2 receptor gene in ATL leukemic cells, indicating that abnormal IL-2 receptor expression in ATL is not due to the structural change of its gene. Hence, we studied the expression of the IL-2 receptor and HTLV-I at the RNA level during short-term cultures of leukemic cells from 9 ATL patients. Cytoplasmic dot hybridization and Northern hybridization revealed that fresh leukemic cells from seven of nine patients expressed a small amount of IL-2 receptor mRNA but HTLV-I RNA was undetectable in all cases. After cultures for up to 7 d, both IL-2 receptor mRNA and HTLV-I RNA (including pX message) expression concomitantly increased, whereas the amounts of other cellular genes, except for beta-actin, did not. The increases in their RNA expression were inhibited by early addition (within 12 h after the beginning of the culture) of cycloheximide, indicating that these increases are mediated by newly synthesized protein(s). These results strongly suggested that IL-2 receptor expression is closely associated with HTLV-I expression in leukemic cells from ATL patients.     

Origin of human T-lymphotrophic virus I-positive T cell lines in adult T cell leukemia. Analysis of T cell receptor gene rearrangement

Using the clone-specific rearrangement of the T cell receptor gene as the genetic marker of the clonotype, we analyzed the clonal origin of the interleukin 2 (IL-2)-dependent human T-lymphotrophic virus I (HTLV-I)-positive T cell lines established from various adult T cell leukemia (ATL) patients. From a patient with chronic ATL, whose leukemic cells proliferated in vitro in response to IL-2, we repeatedly established leukemic T cell clones having the same rearrangement profile of the T beta chain gene as the leukemic cells. By contrast, established cell lines from acute ATL patients had different beta chain gene rearrangements from those of the leukemic cells. These HTLV-I+ T cell lines might not be the direct progeny of the leukemic cells, but that of T cells infected either in vivo or in vitro. These IL-2-reactive nonleukemic T cells might have been selected in vitro, because their leukemic cells failed to respond to IL-2, despite the expression of IL-2 receptor. The analysis of the T cell receptor gene rearrangement may give a new approach for the elucidation of the mechanism of leukemogenesis and the origin of the HTLV-I+ T cell lines in ATL.     

Association between expression of intercellular adhesion molecule-1 and integration of human T-cell-leukemia virus type 1 in adult T-cell leukemia cells

It is known that the expression levels of intercellular adhesion molecule-1 (ICAM-1) in adult T cell leukemia(ATL) cells are high, whereas those in T-lymphoid cells are not. In order to investigate the factors that influence the induction of ICAM-1 molecules, Northern blot analysis to measure the expression level of ICAM-1 mRNAs and Southern blot hybridization to analyze the integration of human T-cell-leukemia virus type 1 (HTLV-1) provirus were done. The levels of ICAM-1 mRNA expression of ATL cells were generally higher than those of T-lymphoid cells. However, ILT-mat cells and ATL16T(-) cells, although they were ATL cells, showed rather low surface ICAM-1 expression and ICAM-1 mRNA expression. Southern blot hybridization showed that only two and four bands were found in ILT-mat and ATL16T(-) cells, respectively, whereas >10 bands were detected in other ATL cells. These results suggest that monoclonal integration of HTLV-1 provirus to the genome of T cell, especially the number of integration sites, is one of the factors for induction of ICAM-1 molecules. J. Clin. Lab. Anal. 11:186–189, 1997. © 1997 Wiley-Liss, Inc.     

Functional and phenotypic studies of Japanese adult T cell leukemia cells.

The cell surface marker profile and functional analysis of peripheral blood lymphocytes from 11 Japanese adult T cell leukemia patients were studied. The phenotypic analysis of Japanese adult T cell leukemia (ATL) cells by a series of 13 monoclonal antibodies showed that all ATL cells are anti-T4 reactive but some differ in their expression of T3, T11, and T12 antigens. Thus, considerable phenotypic heterogeneity exists in these populations of leukemia cells. When analyzed in functional assays, ATL cells were suppressive when added to a pokeweed mitogen- (PWM) driven Ig synthesis system. However, the suppression mechanism seemed to be more complex than originally conceived. ATL cells examined in this study seem to function mainly as an inducer of suppressor cells, and as such, activate normal T8 precursors of suppressor cells rather than function as suppressor effector cells. In addition, no evidence was obtained to suggest that suppression of PWM-stimulated IgG synthesis was mediated by natural killer (NK) activity of ATL cells. Rather, ATL cells seem to be markedly deficient in NK activity. These studies suggest that the majority of ATL cells tested are representative of and seem to be the leukemic counterparts of the T4+ suppressor inducer subset.     

Constitutive activation of different Jak tyrosine kinases in human T cell leukemia virus type 1 (HTLV-1) tax protein or virus-transformed cells.

HTLV-1 infection causes an adult T cell leukemia in humans. The viral encoded protein tax, is thought to play an important role in oncogenesis. Our previous data obtained from a tax transgenic mouse model revealed that tax transforms mouse fibroblasts but not thymocytes, despite comparable levels of tax expression in both tissues. Constitutive tyrosine phosphorylation of a 130-kD protein(s) was observed in the tax transformed fibroblast B line and in HTLV-1 transformed human lymphoid lines, but not in thymocytes from Thy-tax transgenic mice. Phosphotyrosine immunoprecipitation followed by Western blot analysis with a set of Jak kinase specific antibodies, identified p130 as Jak2 in the tax transformed mouse fibroblastic cell line and Jak3 in HTLV-1 transformed human T cell lines. Phosphorylation of Jak2 in tax transformed cells resulted from high expression of IL-6. Tyrosine phosphorylation of this protein could also be induced in Balb/c3T3 cells using a supernatant from the B line, which was associated with induction of cell proliferation. Both phosphorylation and proliferation were inhibited by IL-6 neutralizing antibodies. Constitutive phosphorylation of Jak kinases may facilitate tumor growth in both HTLV-1 infected human T cells and the transgenic mouse model.     

Interleukin-2 receptor (Tac antigen) expressed on adult T cell leukemia cells.

We studied the expression of the interleukin-2 (IL-2) receptor and the proliferative response to exogenous IL-2 of peripheral blood leukemic cells from patients with adult T cell leukemia (ATL) in order to see whether IL-2 receptor expressed on ATL cells is different from normal IL-2 receptor and whether it plays a role in the neoplastic growth in ATL. Peripheral blood leukemic cells from 42 patients with ATL examined expressed IL-2 receptors that were detected by anti-Tac monoclonal antibody when examined immediately after the separation of cells or after the culture for 24 or 48 h. The number of anti-Tac binding sites ranged from 3,100 to 11,400 in fresh cells and from 3,600 to 96,000/cell in short-term cultured leukemic cells, whereas phytohemagglutinin-P (PHA-P)-stimulated normal T cells exhibited 6,900-35,000 anti-Tac binding sites per cell. ATL-derived and human T cell leukemia/lymphoma virus, type I (HTLV-I)-infected cell lines such as MT-1 and Hut102 expressed a much higher number of anti-Tac binding sites. Leukemic cells from 15 patients with ATL examined showed no or very poor proliferative response to various concentrations of immunoaffinity-purified IL-2, although they expressed Tac antigen (Ag). Radiolabeled IL-2 binding experiments demonstrated that ATL leukemic cells could bind IL-2, and they expressed both high and low affinity IL-2 receptors, although the number of high affinity IL-2 receptor was much less than that of low affinity IL-2 receptor and that of anti-Tac binding sites. In contrast, leukemic T cells from a patient with T cell chronic lymphocytic leukemia (CLL), in whom HTLV-I infection was not demonstrated, responded as well as PHA-P-stimulated normal T cells, and their IL-2 receptors, unlike ATL cells, were modulated (down regulated) by anti-Tac antibody. No differences were noted between ATL cells and normal activated T cells in one-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis of the IL-2 receptor. Thus, leukemic cells in ATL spontaneously and continuously express IL-2 receptor, which appears to be abnormally regulated and unresponsive to IL-2. These results, taken together with those on normal IL-2 receptors on HTLV-I-negative T-CLL cells, suggest that abnormal expression of the IL-2 receptor in ATL is closely associated with HTLV-I infection and may play a role in the neoplastic growth of ATL cells.     

High human T cell lymphotropic virus type 1 (HTLV-1)-specific precursor cytotoxic T lymphocyte frequencies in patients with HTLV-1-associated neurological disease

The frequencies of human T cell lymphotropic virus type 1 (HTLV-1)- specific CD8+ precursor cytotoxic T lymphocytes (pCTL) were quantitated from lymphocytes obtained from the peripheral blood and cerebrospinal fluid (CSF) of infected individuals with and without HTLV-1-associated neurological disease. An estimate of the pCTL was obtained by separating CD8+ cells, plating these cells in limiting dilution, and testing wells for HTLV-1 specific lysis. Targets consisted of autologous lymphoblastoid cell lines (LCL) infected with vaccinia constructs expressing HTLV-1 gene products or LCL pulsed with HTLV-1 synthetic peptides. In patients with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), the frequency of HTLV-1 p40X-specific pCTL was at least 40-280-fold higher than in asymptomatic HTLV-1-infected individuals. All HAM/TSP patients (five of five) predominantly recognized HTLV-1 products encoded within the pX region. Lower pCTL to env were demonstrated in three patients, and only one of five HAM/TSP patients had pCTL to gag. A synthetic peptide corresponding to the tax region of HTLV-1 (peptide 11-19, amino acid sequence LLFGYPVYV) was recognized in association with human histocompatibility leukocyte antigen (HLA)-A2 in two HLA-A2 HAM/TSP patients with a high CD8+ pCTL frequency of 1/325 and 1/265, respectively. A second immunodominant region of HTLV-1 tax (peptide 90- 55, amino acid sequence VPYKRIEEL) was identified to be restricted by HLA-B14 in two HLA-B14 HAM/TSP patients with a CD8+ pCTL frequency of 1/640 and 1/1,125, respectively. Lymphocytes from the CSF of a patient with HAM/TSP also showed a pCTL frequency against p40X of similar magnitude to that demonstrated from peripheral blood lymphocytes (PBL). The HLA-A2-mediated CSF pCTL activity to the immunodominant tax- specific peptide 11-19 was also comparable to pCTL from PBL. These results indicate that an extremely high pCTL frequency to HTLV-1 tax- encoded peptides may be related to pathogenesis of myeloneuropathy associated with HTLV-1.     

Functional and phenotypic comparison of human T cell leukemia/lymphoma virus positive adult T cell leukemia with human T cell leukemia/lymphoma virus negative Sézary leukemia, and their distinction using anti-Tac. Monoclonal antibody identifying the human receptor for T cell growth factor.

Adult T cell leukemia (ATL) and Sézary leukemia are malignant proliferations of T lymphocytes that share similar cell morphology and clinical features. ATL is associated with HTLV (human T cell leukemia/lymphoma virus), a unique human type C retrovirus, whereas most patients with the Sézary syndrome do not have antibodies to this virus. Leukemic cells of both groups were of the T3, T4-positive, T8-negative phenotype. Despite the similar phenotype, HTLV-negative Sézary leukemic cells frequently functioned as helper cells, whereas some HTLV-positive ATL and HTLV-positive Sézary cells appeared to function as suppressors of immunoglobulin synthesis. One can distinguish the HTLV-positive from the HTLV-negative leukemias using a monoclonal antibody (anti-Tac) that appears to identify the human receptor for T cell growth factor (TCGF). Resting normal T cells and most HTLV-negative Sézary cells were Tac-negative, whereas all ATL cell populations were Tac-positive. The observation that ATL cells manifest TCGF receptors suggests the possibility that an abnormality of the TCGF-TCGF receptor system may partially explain the uncontrolled growth of these cells.     

人白血病细胞株重组激活基因表达及T细胞受体基因重排的检测

背景:淋巴细胞特异性重组激活基因编码的重组激活基因1与重组激活基因2蛋白是参与V(D)J重排机制的重要的重组酶。除参与V(D)J重排以外,近年的研究结果表明重组激活基因介导的转位作用可能与染色体易位及淋巴性恶性肿瘤的发生有关,但迄今尚未有明确定论。目的:检测重组激活基因、DNA修复因子Ku70/Ku80和末端脱氧核苷转移酶mRNA表达以及T细胞受体基因重排在人白血病和淋巴瘤细胞株的发生情况。设计:重复测量实验。单位:南方医科大学生物技术学院分子免疫研究所。材料:T淋巴白血病细胞株Jurkat和6T-CEM购自上海细胞生物研究所;T淋巴白血病细胞株Molt-4,皮肤T细胞淋巴瘤细胞株HuT102,Burkitt’s淋巴瘤细胞株Raji和Daudi以及原髓细胞白血病细胞株HL-60和慢性髓原白血病细胞株K562均由本实验室保存。细胞用含有体积分数0.1胎牛血清的RPMI1640培养基于37℃,体积分数0.05CO2条件下培养。方法:实验于2005-10/2006-01在南方医科大学生物技术学院分子免疫研究所完成。采用反转录聚合酶链反应检测重组激活基因1,重组激活基因2,非同源末端连接装置途径中的DNA修复因子Ku70/Ku80,以及末端脱氧核苷转移酶mRNA表达;采用巢式、半巢式聚合酶链反应、连接介导的聚合酶链反应等方法检测T细胞受体重排删除DNA环和T细胞受体β链重组信号序列两端的断裂点。了解参与V(D)J重排过程的基因表达和T细胞受体基因重排中间体的产生情况。主要观察指标:重组激活基因、DNA修复因子Ku70/Ku80和末端脱氧核苷转移酶mRNA表达以及T细胞受体基因重排在人白血病和淋巴瘤细胞株的发生情况。结果:反转录聚合酶链反应检测结果显示:重组激活基因1mRNA在4种T细胞株中均被检测到,在两种B细胞株和两种髓性白血病细胞株中未检测到;重组激活基因2和末端脱氧核苷转移酶mRNA表达仅在Jurkat,Molt-4和6T-CEM3种T细胞株中检测到,但在6T-CEM表达较弱;除HL-60细胞未检测到Ku80表达外,所有细胞株均检测到Ku70和Ku80表达。对4种T细胞株T细胞受体重排中间体检测结果表明:仅在Jurkat细胞中检测到Dβ2-Jβ2sjTRECs与Dβ25’端和3’RSS断点,表明Jurkat细胞发生T细胞受体基因重排。同时发现JurkatTCRDβ2-Jβ2重排删除环结合区具有明显的多样性特征。结论:重组激活基因可能与T细胞白血病具有更为密切的关系。Jurkat细胞有可能成为研究重组激活基因与T细胞淋巴性肿瘤的一个潜在的细胞模型。     

B7-H1基因在白血病细胞中的表达及其临床意义

本研究通过检测B7-H1基因在多种白血病细胞中的表达水平,探讨其临床意义。采用SYBR GreenⅠ实时定量PCR法检测9株白血病细胞系、4株IFN-γ体外诱导后的白血病细胞系,59例原代急性白血病细胞、10例原代白血病细胞诱导生成的树突状细胞(DC)以及2株实体肿瘤细胞系,10例正常人骨髓单个核细胞中B7-H1mRNA的表达水平,并对59例急性白血病患者的治疗反应与其白血病细胞中B7-H1基因表达水平之间的相关性进行了分析。结果显示:B7-H1 mRNA在白血病细胞系、原代急性白血病细胞中的表达水平较低,在IFN-γ体外诱导后的白血病细胞系、原代白血病细胞诱导生成的DC中的表达水平明显上调,在化疗后未获完全缓解(CR)的患者白血病细胞中B7-H1 mRNA表达水平明显高于化疗后获得CR的患者。结论:B7-H1基因在白血病细胞中的表达水平较低,但在某些因素作用下其表达水平明显上调。白血病细胞中B7-H1基因表达水平与患者的治疗反应有显著相关性。     

HTLV-1 propels untransformed CD4 lymphocytes into the cell cycle while protecting CD8 cells from death

Human T cell leukemia virus type 1 (HTLV-1) infects both CD4⁺ and CD8⁺ lymphocytes, yet it induces adult T cell leukemia/lymphoma (ATLL) that is regularly of the CD4⁺ phenotype. Here we show that in vivo infected CD4⁺ and CD8⁺ T cells displayed similar patterns of clonal expansion in carriers without malignancy. Cloned infected cells from individuals without malignancy had a dramatic increase in spontaneous proliferation, which predominated in CD8⁺ lymphocytes and depended on the amount of tax mRNA. In fact, the clonal expansion of HTLV-1–positive CD8⁺ and CD4⁺ lymphocytes relied on 2 distinct mechanisms — infection prevented cell death in the former while recruiting the latter into the cell cycle. Cell cycling, but not apoptosis, depended on the level of viral-encoded tax expression. Infected tax-expressing CD4⁺ lymphocytes accumulated cellular defects characteristic of genetic instability. Therefore, HTLV-1 infection establishes a preleukemic phenotype that is restricted to CD4⁺ infected clones.     

Adult T cell leukemia/lymphoma (ATL)

Adult T cell leukemia/lymphoma(ATL) is an aggressive, fatal malignancy associated with human T-lymphotropic virus type I(HTLV-I). The median survival time of acute- and lymphoma-type ATL is 6 and 10 months, respectively. According to recent reports, nearly half of the ATL patients who received allogeneic hematopoietic stem cell transplantation could survive without disease for over 3 years. However, the population of patients who are eligible for conventional transplantation is extremely limited. Therefore, a reduced-intensity allogeneic stem cell transplantation(RIST) is applied to ATL patients and a multi-center phase I clinical trial is now underway. In our institute, 5 patients, who received RIST, are all alive, with 1 case relapsed after 6 months. Thus, RIST is considered very promising.