Development-dependent expression of cyclin D3 in precursor T-cell lymphoblastic leukemia/lymphoma

In contrast to the clear oncogenic role of cyclins D1 and D2, cyclin D3 is suggested to have a role in the initiation and/or maintenance of differentiation in a lineage-associated manner in addition to its basic role in proliferation. Recently, it has been reported that in cyclin D3-deficient mice, normal expansion of T lymphocytes is impaired because of maturation arrest at the double-negative thymocyte stage, suggesting a crucial role for cyclin D3 in early T-cell development. Therefore, cyclin D3 expression was examined in 36 human precursor T-lymphoblastic leukemia/lymphomas (T-LBLL), a neoplastic counterpart of T cells at the early developmental stages of differentiation. Using a standard panel of differentiation markers, all T-LBLL were categorized into four stages according to differentiation: progenitor, double-negative, double-positive, and single-positive stages. Cyclin D3 expression was initiated at the boundary between double-negative and double-positive stages, and was sustained in the single-positive stage. T-cell receptor was expressed simultaneously with cyclin D3, whereas CD79a expression was specific in the double-negative stage, and thus it was inversely correlated with that of cyclin D3. Taken together with the crucial and non-redundant role in T-cell development in mice, this molecule is suggested to play an important role in human T-cell development.     

Effects of thymocytes on marrow cells from normal and busulfan-treated mice

To study the effects of thymocytes on hemopoiesis, we 1) cocultured marrow cells with and without thymocytes in an erythroid burst (BFU-E) culture system, 2) injected marrow cells with and without thymocytes into supralethally irradiated mice to assay CFU-S, and 3) assessed the survival of supralethally irradiated mice transplanted with marrow cells with or without thymocytes. The marrow cells used were either from mice given six injections of busulfan and then permitted to rest for 2, 5, or 10 weeks or from mice treated similarly with the busulfan vehicle alone. Thymocytes did not alter spleen surface colony counts or survivorship in any of the test groups. Thymocytes did effect an increase in BFU-E cultured from marrow obtained from the vehicle-treated mice but not from marrow of busulfan-treated mice. Thus, in addition to decreasing the population of hemopoietic precursors in the marrow, busulfan alters the nature of the remaining early erythroid precursor cell population rendering it unresponsive to thymocytes in vitro.     

L615白血病鼠胸腺和脾脏淋巴细胞脱氢酶同工酶的研究

本文对比观察L615鼠和615鼠胸腺及脾脏淋巴细胞的乳酸脱氢酶同工酶(LDH Isoenzyme)、6-磷酸葡萄糖脱氢酶同工酶(G6PD Isoenzyme).结果表明L615鼠与615鼠相比,胸腺淋巴细胞G6PD-3活性明显下降.脾脏淋巴细胞LDH-1、2活性显著减弱,LDH-5活性相应明显增强,同时G6PD-1活性上升,G6PD-2活性下降.LDH、G6PD全酶活性应用全自动扫描显微分光光度计进行单一细胞酶活性全面积扫描,结果为L615白血病鼠胸腺淋巴细胞G6PD及脾脏淋巴细胞LDH、G6PD酶活性明显增强.     

低剂量率低水平辐射对机体某些免疫功能的影响

用⁶⁰CoY源, 剂量率0.068mGy/分, 对C57BL/6小鼠进行全身照射, 照射剂量为24.4、48.8,73.2,97.6和122.0mGy.照射后检测小鼠脾脏抗体形成细胞(PFC),胸腺细胞³H-TdR自发掺入率。脾脏及胸腺有核细胞数, 脾细胞酸性α醋酸蒙酯酶(ANAE)染色的变化。结果表明, 当照射荆瑶为24.4mGy时, 胸腺细胞自发掺八率明显增高, 当照射剂量为73.2mGy时, 脾脏PFc明显增加。以上低剂量率小剂量作用下呈现出的机体某些免疫功能的刺激作用, 并非由于调节性T细胞数量的变化所致。讨论了引起不同免疫学多数刺激效应均不同辐射剂量与各参数辐射敏感住之闻的可能关系。     

艾氏腹水癌腹水对刀豆素A诱导胸腺细胞增殖反应的影响

本文究研了艾氏腹水癌腹水对刀豆素A诱导的胸腺细胞增殖反应的影响,发现腹水中至少存在两种对胸腺细胞增殖反应起相反作用的因子,一种为活化因子,来源于宿主的粘附细胞,能明显提高胸腺细胞对刀豆素A的反应,作用迅速,发生于细胞接受有丝分裂原刺激之前;另一种为抑制因子,来源于肿瘤细胞。     

Modulation of cadmium induced alterations in murine thymocytes by piperine: oxidative stress, apoptosis, phenotyping and blastogenesis

Piperine, a main component of Piper longum Linn. and Piper nigrum Linn., is a plant alkaloid with a long history of medicinal use in Indian medicine. It is known to exhibit a variety of biological activities which include anti-pyretic, anti-inflammatory, anti-depressant, hepatoprotective and antitumor. Its immunomodulatory role has so far been limited to humoral response. The influence of piperine on murine thymocytes, immunocompromised by cadmium has been reported by us in this investigation. The various biochemical parameters such as oxidative stress markers (ROS and GSH), Bcl-2 protein expression, mitochondrial membrane potential, caspase-3 activity, DNA damage, blastogenesis and T lymphocyte phenotypes were determined. Cadmium (25 microM) induced apoptosis earliest at 6 h. Alterations in ROS and GSH preceded mitochondrial membrane depolarization and caspase-3 activation followed by apoptosis. The phenotypic changes occurred at 18 h and blastogenesis at 72 h. Various conc. of piperine (1, 10 and 50 microg/ml) when added along with Cd (25 microM) from 1.5 to 72 h, caused a dose and time dependent amelioration in all the cellular events mentioned above. Modulation of oxidative stress has earlier been reported to reduce Cd induced apoptosis in murine lymphocytes. Inhibition of the ROS production and replenishment of GSH by piperine, may in part be responsible for the suppression of downstream cascade of events, i.e. apoptosis, blastogenesis and T lymphocyte phenotyping. The study clearly demonstrated the anti-oxidative, anti-apoptotic, and restorative ability against cell proliferative mitogenic response and phenotypic alterations by piperine, suggesting its therapeutic usefulness in immunocompromised conditions.     

Developmental shift in TcR-mediated rescue of thymocytes from glucocorticoid-induced apoptosis

Glucocorticoid hormone (GC) production by thymic epithelial cells influences TcR signalling in DP thymocytes and modifies their survival. In the present work, we focused on exploring details of GC effects on DP thymocyte apoptosis with or without parallel TcR activation in AND transgenic mice, carrying TcR specific for pigeon cytochrome C, in vivo. Here we show that the glucocorticoid receptor (GR) protein level was the lowest in DP thymocytes, and it was slightly down-regulated by GC analogue, anti-CD3, PCC and combined treatments as well. Exogenous GC analogue treatment or TcR stimulation alone lead to marked DP cell depletion, coupled with a significant increase of early apoptotic cell ratio (AnnexinV staining), marked abrogation of the mitochondrial function in DP cells (CMXRos staining), and significant decrease in the Bcl-2(high) DP thymocyte numbers, respectively. On the other hand, the simultaneous exposure to these two proapototic signals effectively reversed all the above-described changes. The parallel analysis of CD4 SP cell numbers, AnnexinV, CMXRos, Bcl-2 and GR stainings revealed, that the GR and TcR signals were not antagonistic on the mature thymocytes. These data provide experimental evidence in TcR transgenic mice, in vivo, that when TcR activation and GR signals are present simultaneously, they rescue double positive thymocytes from programmed cell death. The two separate signalling pathways merge in DP thymocytes at such important apoptosis regulating points as the Bcl-2 and GR, showing that their balanced interplay is essential in DP cell survival.     

X-ray irradiation selectively kills thymocytes of different stages and impairs the maturation of donor-derived CD4~+CD8~+ thymocytes in recipient thymus

The aim of the present study was to determine whether the sensitivity of thymocytes to X-ray radiation depends on their proliferative states and whether radiation impairs the maturation of donor-derived thymocytes in recipient thymus.We assigned 8-week-old C57BL/6J mice into three treatment groups:1) untreated;2) X-ray radiation;3) X-ray radiation plus bone marrow transplantation with donor bone marrow cells from transgenic mice express-ing enhanced green fluorescent protein(GFP) on a universal promoter.After 4 weeks,the size of the thymus,the number and proliferation of thymocytes and ratios of different stage thymocytes were analyzed by immunohisto-chemistry and flow cytometry.The results showed that:1) CD4+CD8+ thymocytes were more sensitive to X-ray radiation-induced cell death than other thymocytes;2) the proliferative capacity of CD4+CD8+ thymocytes was higher than that of other thymocytes;3) the size of the thymus,the number of thymocytes and ratios of thymo-cytes of different stages in irradiated mice recovered to the normal level of untreated mice by bone marrow trans-plantation;4) the ratio of GFP-positive CD4+CD8+ thymocytes increased significantly,whereas the ratio of GFP-positive CD4+ or CD8+ thymocytes decreased significantly.These results indicate that the degree of sensitivity of thymocytes to X-ray radiation depends on their proliferative states and radiation impairs the maturation of donor-derived CD4+CD8+ thymocytes in recipient thymus.