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癌细胞株的发生情况。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细胞淋巴癌细胞株HuT102，Burkitt’s淋巴癌细胞株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0．05C02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B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。主耍观察指标：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癌细胞株的发生情况。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DB2-J132 sjTRECs与DB25’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Jurkat TCR Dβ2-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。     

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。     

Identification of the human T cell lymphoma virus in B cell lines established from patients with adult T cell leukemia.

Cell lines were established from the peripheral blood of two patients with adult T cell leukemia. In contrast to our previous experience, where all such lines expressed T cell markers, these two cell lines expressed B cell antigens and Ig light chains (kappa on CF-2, lambda on HS). Human T cell lymphoma proviral (HTLV) sequences were demonstrated in both cell lines. Since only a portion of the cells in culture expressed Ig light chains, experiments were carried out to exclude the possibility that the cultures were not a mixture of B and T or non-B cells. Cells that expressed kappa- or lambda-light chains were separated by cell sorting from kappa- or lambda-negative cells and replaced in culture. Light chain negative cells reexpressed light chains after time in culture. After 5-azacytidine treatment of the cell lines, all cells expressed Ig light chains. These studies show that the human retrovirus HTLV, which has been demonstrated to be associated with certain T cell malignancies, can infect B cells or B cell precursors.     

T cell receptor alpha-chain gene rearrangements in B-precursor leukemia are in contrast to the findings in T cell acute lymphoblastic leukemia. Comparative study of T cell receptor gene rearrangement in childhood leukemia.

We have analyzed T cell receptor alpha-chain gene configuration using three genomic joining (J) region probes in 64 children with acute lymphoblastic leukemia (ALL). 11 out of 18 T-ALLs were T3 positive; alpha-chain gene rearrangements were demonstrated in only two of 18, indicating that the majority of T-ALLs would have rearrangements involving J alpha segments located upstream of these probes. In contrast, 15 out of 46 B-precursor ALLs showed rearrangements of the alpha-chain gene and J alpha segments located approximately 20-30 kb upstream of the constant region were involved in 13 of these patients. Nine of 15 B-precursor ALLs with rearranged alpha-chain genes had rearrangements of both gamma- and beta-chain genes, whereas the remaining six had no rearrangements of gamma- and beta-chain genes. These findings indicated that alpha-chain gene rearrangement is not specific for T lineage cells and gamma- and/or beta-chain gene rearrangement does not appear essential for alpha-chain gene rearrangement, at least in B-precursor leukemic cells.     

Rat lymphoid cell lines producing human T cell leukemia virus. II. Constitutive expression of rat interleukin 2 receptor

Three rat lymphoid cell lines (TARS-1, TARL-2, and TART-1) (12) transformed by human T cell leukemia/lymphoma virus I (HTLV-I) had rearrangement of the beta chain gene of the T cell antigen receptor, and had integrated proviral DNA from HTLV-I in their genomes. As is the case with adult T cell leukemia (ATL)-derived human T cell lines transformed by HTLV-I, these rat cell lines unequivocally expressed interleukin 2 (IL-2) receptor, as determined by radiolabeled IL-2 binding. By Scatchard plot analysis, one of the cell lines, TART-1, proved to have high affinity receptors (Ka = 1.3 X 10(11)/M and 8.8 X 10(9)/M). Rat IL-2 receptor, not human IL-2 receptor, was expressed on HTLV+ rat cell lines, as demonstrated by the fact that they expressed antigens reactive with monoclonal antibodies (ART-18) against rat IL-2 receptor, but not with anti-Tac antibodies. The collective evidence indicates that the endogenous IL-2 receptor gene is activated in human and rat lymphoid cell lines with HTLV-I production. The mechanism of abnormal IL-2 receptor expression in HTLV infection is discussed.     

T cell receptor beta chain gene rearrangement shared by murine T cell lines derived from a site of autoimmune inflammation.

Advances in our understanding of the structure and molecular biology of the T lymphocyte antigen-receptor have now made it feasible to study human autoimmune diseases using new approaches. One such approach involves cloning of T cells from sites of autoimmune pathology followed by identification of putative disease-related T cell oligoclonality at the level of the T cell receptor gene rearrangements. We have now tested the feasibility of this approach in an animal model of autoimmunity, murine experimental allergic encephalomyelitis (EAE). Spinal cord-derived, self (murine) myelin basic protein (MBP)-reactive T cell lines and sublines were analyzed at the level of their receptor beta chain rearrangements using Southern blots. We now report that the MBP-reactive T cell lines and sublines derived from the spinal cords of four of five SJL/J mice with EAE share a 14.5-kb rearranged T cell receptor beta 1 band on Southern blots. A spinal cord-derived T cell line that was reactive to purified protein derivative of tuberculin (PPD), several lymph node-derived ovalbumin- and PPD-reactive T cell lines, as well as one MBP-reactive spinal cord-derived T cell line did not share this 14.5-kb rearranged beta 1 band. These results suggest that analysis of the antigen receptors used by T cells cloned from sites of inflammation may be a useful initial approach for identifying pathogenetically relevant T cells in the study of certain human autoimmune diseases.     

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.     

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.     

Rat lymphoid cell lines with human T cell leukemia virus production. I. Biological and serological characterization

Cocultivation of spleen cells, lymph node cells, and thymocytes of female Wistar-King-Aptekman rats with short-term cultured male adult T cell leukemia (ATL) cells in the presence of 5-bromo-2'-deoxyuridine (BrdUrd) resulted in the establishment of rat lymphoid cell lines, TARS-1, TARL-2, and TART-1. Cytogenetic analysis of the three cell lines showed a female rat karyotype with 42 chromosomes. The surface phenotypes of TARS-1 and TART-1 were those of rat T cells. TARL-2 was only positive for rat Ia and leukocyte common antigens. The cell lines continuously produced a type C retrovirus, human T cell leukemia virus (HTLV) and expressed ATL-associated antigens. TARS-1 and TART-1, but not TARL-2 were transplantable into newborn syngeneic rats and nude mice. These results strongly indicate that HTLV not only immortalizes, but also transforms rat T cells in vitro. Adult rats immunized with either TARS-1 or TARL-2 produced antibodies specific for HTLV. The biochemical analysis of the antigens that reacted with rat sera revealed that they are the two HTLV-specific polypeptides, p24 and p28.     

New insights on human T cell development by quantitative T cell receptor gene rearrangement studies and gene expression profiling

To gain more insight into initiation and regulation of T cell receptor (TCR) gene rearrangement during human T cell development, we analyzed TCR gene rearrangements by quantitative PCR analysis in nine consecutive T cell developmental stages, including CD34+ lin- cord blood cells as a reference. The same stages were used for gene expression profiling using DNA microarrays. We show that TCR loci rearrange in a highly ordered way (TCRD-TCRG-TCRB-TCRA) and that the initiating Ddelta2-Ddelta3 rearrangement occurs at the most immature CD34+CD38-CD1a- stage. TCRB rearrangement starts at the CD34+CD38+CD1a- stage and complete in-frame TCRB rearrangements were first detected in the immature single positive stage. TCRB rearrangement data together with the PTCRA (pTalpha) expression pattern show that human TCRbeta-selection occurs at the CD34+CD38+CD1a+ stage. By combining the TCR rearrangement data with gene expression data, we identified candidate factors for the initiation/regulation of TCR recombination. Our data demonstrate that a number of key events occur earlier than assumed previously; therefore, human T cell development is much more similar to murine T cell development than reported before.     

Immunoglobulin mu-chain gene rearrangement in a patient with T cell acute lymphoblastic leukemia

A 6-yr-old girl with T cell acute lymphoblastic leukemia (ALL) is described. She had a mediastinal mass and her leukemic cells expressed T cell-associated antigens (Leu 1+, OKT3+, OKT9+, and OKT10+). When we examined genomic DNA from the leukemic cells, we detected Ig mu-chain gene rearrangement with germ-line configuration of light chain genes. As reported recently, detecting Ig gene rearrangement has become an important procedure for further classifying B cell precursor cells. This case, however, suggests that there is also heterogeneity among patients with T cell ALL, not only at the level of cell surface phenotypes, but also at the level of the Ig gene. These findings have major implications when we consider both the ontogenesis of these leukemic cells and the normal differentiation of human lymphocytes.     

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.