A model of human acute lymphoblastic leukemia in immune-deficient SCID mice

A human acute lymphoblastic leukemia (ALL) cell line that was transplanted into immune-deficient SCID mice proliferated in the hematopoietic tissues, invaded various organs, and led to the death of the mice. The distribution of leukemic cells in SCID mice was similar to the course of the disease in children. A-1 cells marked with a retrovirus vector showed clonal evolution after the transplant. SCID mice that were injected with bone marrow from three patients with non-T ALL had leukemic cells in their bone marrow and spleen. This in vivo model of human leukemia is an approach to understanding leukemic growth and progression and is a novel system for testing new treatment strategies.     

Myc-induced T cell leukemia in transgenic zebrafish

The zebrafish is an attractive model organism for studying cancer development because of its genetic accessibility. Here we describe the induction of clonally derived T cell acute lymphoblastic leukemia in transgenic zebrafish expressing mouse c-myc under control of the zebrafish Rag2 promoter. Visualization of leukemic cells expressing a chimeric transgene encoding Myc fused to green fluorescent protein (GFP) revealed that leukemias arose in the thymus, spread locally into gill arches and retro-orbital soft tissue, and then disseminated into skeletal muscle and abdominal organs. Leukemic cells homed back to the thymus in irradiated fish transplanted with GFP-labeled leukemic lymphoblasts. This transgenic model provides a platform for drug screens and for genetic screens aimed at identifying mutations that suppress or enhance c-myc- induced carcinogenesis.     

Transplanted precursors of nerve cells: their fate in the cerebellums of young rats

The multiplying cells of the external granular layer in 7-day-old rats were labeled with [(3)H]thymidine. Slabs of the cerebellum were transplanted into the same region of uninjected hosts of the same age. The transplanted, undifferentiated cells of the donors migrated actively in the cerebellar cortex of the hosts and apparently differentiated there into basket and granule cells.     

中草药红茶菌的制备及其体外抗口蹄疫病毒活性

[目的]研究中草药红茶菌的细胞、乳鼠毒性以及对口蹄疫病毒在体外的抗病毒活性。[方法]将中草药红茶菌过滤,用细胞培养液稀释,分别接种在BHK21细胞上观察细胞生长情况,评价其对细胞的毒性作用。将中草药红茶菌用灭菌水稀释,分别接种3日龄乳鼠,观察乳鼠生长、健康状态和接种部位变化情况,评价其对乳鼠的毒性作用。用稀释的中草药红茶菌与浓度为1000LD_50的口蹄疫病毒等量混合,37℃条件下作用30min,接种3日龄乳鼠,观察乳鼠发病死亡情况,估算中草药红茶菌体外可杀灭口蹄疫病毒的最大使用浓度。用稀释的中草药红茶菌与口蹄疫病毒混合,接种BHK21细胞,观察致细胞病变效应,记录不同稀释度的中草药红茶菌对口蹄疫病毒的杀灭效果。[结果]BHK21细胞和乳鼠试验表明,中草药红茶菌在1：4稀释后,对BHK21细胞无毒性反应,并可有效抑制1000TCID_50口蹄疫病毒在BHK21细胞生长繁殖;1：2稀释的红茶菌微生态制剂对3日龄乳鼠无毒性反应,并可有效杀灭1000LD_50口蹄疫病毒。[结论]中草药红茶菌是一种安全性好且对口蹄疫病毒有较好杀灭作用的口蹄疫预防中草药微生态制剂。     

Appearance of a new nucleosomal protein during differentiation of human leukemia (HL-60) cells

A 60-kilodalton protein was identified in chromatin digested by micrococcal nuclease during retinoic acid-induced differentiation of human leukemia (HL-60) cells to mature-like granulocytes. The protein was not detected in a retinoic acid-resistant variant of the HL-60 cell line treated with retinoic acid, in HL-60 cells induced with dimethyl sulfoxide, or in normal human granulocytes. This protein may have an important role in the regulation of retinoic acid-induced leukemic cell differentiation.     

The molecular control of blood cell development

The establishment of a cell culture system for the clonal development of blood cells has made it possible to identify the proteins that regulate the growth and differentiation of different blood cell lineages and to discover the molecular basis of normal and abnormal cell development in blood forming tissues. A model system with myeloid blood cells has shown that (i) normal blood cells require different proteins to induce cell multiplication (growth inducers) and cell differentiation (differentiation inducers), (ii) there is a hierarchy of growth inducers as cells become more restricted in their developmental program, and (iii) a cascade of interactions between proteins determines the correct balance between immature and mature cells in normal blood cell development. Gene cloning has shown that there is a family of different genes for these proteins. Normal protein regulators of blood cell development can control the abnormal growth of certain types of leukemic cells and suppress malignancy by inducing differentiation to mature nondividing cells. Chromosome abnormalities that give rise to malignancy in these leukemic cells can be bypassed and their effects nullified by inducing differentiation, which stops cells from multiplying. These blood cell regulatory proteins are active in culture and in the body, and they can be used clinically to correct defects in blood cell development.     

Expanded HIV-1 cellular tropism by phenotypic mixing with murine endogenous retroviruses

In view of the current interest in in vivo murine models for acquired immunodeficiency syndrome (AIDS), the interaction between human immunodeficiency virus type 1 (HIV-1) and endogenous murine leukemia virus (MuLV)-related retroviruses was investigated with a human leukemic T cell line (PF-382x) that acquired xenotropic MuLV (X-MuLV) after in vivo passage in immunosuppressed mice. Despite similar levels of membrane CD4 expression and HIV-1 125I-labeled gp 120 binding, a dramatic acceleration in the time course of HIV-1 infection was observed in PF-382x compared to its X-MuLV-negative counterpart (PF-382). Moreover, PF-382 cells coinfected by X-MuLV and HIV-1 generated a progeny of phenotypically mixed viral particles, enabling HIV-1 to productively infect a panel of CD4- human cells, including B lymphoid cells and purified normal peripheral blood CD4-/CD8+ T lymphocytes. Mixed viral phenotypes were also produced by human CD4+ T cells coinfected with an amphotropic MuLV-related retrovirus (A-MuLV) and HIV-1. These data show that endogenous MuLV acquired by human cells transplanted into mice can significantly interact with HIV-1, thereby inducing important alterations of HIV-1 biological properties.     

Initiating and cancer-propagating cells in TEL-AML1-associated childhood leukemia

Understanding cancer pathogenesis requires knowledge of not only the specific contributory genetic mutations but also the cellular framework in which they arise and function. Here we explore the clonal evolution of a form of childhood precursor-B cell acute lymphoblastic leukemia that is characterized by a chromosomal translocation generating a TEL-AML1 fusion gene. We identify a cell compartment in leukemic children that can propagate leukemia when transplanted in mice. By studying a monochorionic twin pair, one preleukemic and one with frank leukemia, we establish the lineal relationship between these "cancer-propagating" cells and the preleukemic cell in which the TEL-AML1 fusion first arises or has functional impact. Analysis of TEL-AML1-transduced cord blood cells suggests that TEL-AML1 functions as a first-hit mutation by endowing this preleukemic cell with altered self-renewal and survival properties.     

SD大鼠睾丸支持细胞的分离、培养、纯化及鉴定

为进一步简化、优化SD大鼠睾丸支持细胞的体外培养条件及鉴定方法,采用三酶两步消化法和差异贴壁法分离、培养、纯化SD大鼠支持细胞,并用HE染色、油红染色、Feulgen染色及透射电镜扫描其超微结构予以鉴定。结果表明：平均0．10g睾丸组织可获得2．5×10^6个支持细胞,细胞存活率90％以上,体外培养5h后开始贴壁,96h后细胞生长速率下降,其对数生长期为3—7d,整个体外生长周期约为10～15d。对获得的纯化细胞进行鉴定,发现其形态结构及超微结构与支持细胞的形态特征一致。可见,采用三酶两步消化法和差异贴壁法,可达到分离、培养、纯化SD大鼠支持细胞的目的。     

Effectiveness of donor natural killer cell alloreactivity in mismatched hematopoietic transplants

T cells that accompany allogeneic hematopoietic grafts for treating leukemia enhance engraftment and mediate the graft-versus-leukemia effect. Unfortunately, alloreactive T cells also cause graft-versus-host disease (GVHD). T cell depletion prevents GVHD but increases the risk of graft rejection and leukemic relapse. In human transplants, we show that donor-versus-recipient natural killer (NK)-cell alloreactivity could eliminate leukemia relapse and graft rejection and protect patients against GVHD. In mice, the pretransplant infusion of alloreactive NK cells obviated the need for high-intensity conditioning and reduced GVHD. NK cell alloreactivity may thus provide a powerful tool for enhancing the efficacy and safety of allogeneic hematopoietic transplantation.     

Hematopoietic stem cell quiescence maintained by p21cip1/waf1

Relative quiescence is a defining characteristic of hematopoietic stem cells, while their progeny have dramatic proliferative ability and inexorably move toward terminal differentiation. The quiescence of stem cells has been conjectured to be of critical biologic importance in protecting the stem cell compartment, which we directly assessed using mice engineered to be deficient in the G1 checkpoint regulator, cyclin-dependent kinase inhibitor, p21cip1/waf1 (p21). In the absence of p21, hematopoietic stem cell proliferation and absolute number were increased under normal homeostatic conditions. Exposing the animals to cell cycle-specific myelotoxic injury resulted in premature death due to hematopoietic cell depletion. Further, self-renewal of primitive cells was impaired in serially transplanted bone marrow from p21-/- mice, leading to hematopoietic failure. Therefore, p21 is the molecular switch governing the entry of stem cells into the cell cycle, and in its absence, increased cell cycling leads to stem cell exhaustion. Under conditions of stress, restricted cell cycling is crucial to prevent premature stem cell depletion and hematopoietic death.     

哺乳动物胚胎干细胞研究进展

胚胎干细胞(embryonic stem cells, ES)是指从桑椹胚或附植前囊胚内细胞团分离的多潜能细胞,它具有体外培养无限增殖、自我更新和多向分化的特性。无论在体外还是体内环境,ES细胞都能被诱导分化为机体几乎所有的细胞类型。自1981年Evans和Kaufman首次成功分离小鼠ES细胞,国内外研究人员已在仓鼠、大鼠、兔、猪、牛、绵羊、山羊、水貂、恒河猴、美洲长尾猴以及人类都分离获得了ES细胞,而且已经证明小鼠ES细胞可以分化为心肌细胞、造血细胞、卵黄囊细胞、骨髓细胞、平滑肌细胞、脂肪细胞、软骨细胞、成骨细胞、内皮细胞、黑素细胞、神经细胞、神经胶质细胞、少突胶质细胞、淋巴细胞、胰岛细胞、滋养层细胞等。人类ES细胞也可以分化为滋养层细胞、神经细胞、神经胶质细胞、造血细胞、心肌细胞等。ES细胞不仅可以作为体外研究细胞分化和发育调控机制的模型,而且还可以作为一种载体,将通过同源重组产生的基因组的定点突变导入个体,更重要的是,ES细胞将会给人类移植医学带来一场革命。     

狗舌草提取物体内抗L1210白血病效果的研究

建立淋巴性白血病L1210细胞荷瘤DBA/2小鼠模型,从荷瘤鼠T/C及腹围测定、荷瘤鼠腹水中L1210细胞形态观察、荷瘤鼠白细胞象检查和骨髓象检查几方面,检查狗舌草60%乙醇提取物在体内对淋巴性白血病的作用效果。发现狗舌草60%乙醇提取物与单猪屎豆碱和槲皮素在体内抑制淋巴性白血病方面具有一致性。     

Human leukemic cells: in vitro growth of colonies containing the Philadelphia (Ph) chromosome

Human leukemic cells with a marker (Philadelphia; Ph(1)) chromosome gave rise to granulocytic and mononuclear cell colonies when grown in vitro. All metaphases from a single colony were either Ph(1) positive or Ph(1) negative. No colonies contained a mixed cell population. This suggests that leukemic and normal cells exist simultaneously and that in vitro colonies are clonal in origin.     

The granulocyte-macrophage colony-stimulating factors

The granulocyte-macrophage colony-stimulating factors are well-characterized specific glycoproteins that interact to control the production, differentiation, and function of two related white cell populations of the blood, the granulocytes and monocyte-macrophages. Widely produced in the body, these regulators probably play an important role in resistance to infections. The proliferation of myeloid leukemia cells remains dependent on stimulation by colony-stimulating factors, although one of them also has the ability to suppress leukemic populations by inducing terminal differentiation.     

Modeling the initiation and progression of human acute leukemia in mice

Our understanding of leukemia development and progression has been hampered by the lack of in vivo models in which disease is initiated from primary human hematopoietic cells. We showed that upon transplantation into immunodeficient mice, primitive human hematopoietic cells expressing a mixed-lineage leukemia (MLL) fusion gene generated myeloid or lymphoid acute leukemias, with features that recapitulated human diseases. Analysis of serially transplanted mice revealed that the disease is sustained by leukemia-initiating cells (L-ICs) that have evolved over time from a primitive cell type with a germline immunoglobulin heavy chain (IgH) gene configuration to a cell type containing rearranged IgH genes. The L-ICs retained both myeloid and lymphoid lineage potential and remained responsive to microenvironmental cues. The properties of these cells provide a biological basis for several clinical hallmarks of MLL leukemias.     

Transformation of chick embryo neuroretinal cells by Rous sarcoma virus in vitro: induction of cell proliferation

Neuroretinal cells from 7-day-old chick embryos are transformed and induced to proliferate after infection with Rous sarcoma virus in vitro. Susceptibility of neuroretinal cells to the virus is also dependent on the stage of development since infection of cells from 10-day-old embryos is uneffective.     

Recombinant human granulocyte colony-stimulating factor: effects on normal and leukemic myeloid cells

Experiments were conducted to isolate and characterize the gene and gene product of a human hematopoietic colony-stimulating factor with pluripotent biological activities. This factor has the ability to induce differentiation of a murine myelomonocytic leukemia cell line WEHI-3B(D+) and cells from patients with newly diagnosed acute nonlymphocytic leukemia (ANLL). A complementary DNA copy of the gene encoding a pluripotent human granulocyte colony-stimulating factor (hG-CSF) was cloned and expressed in Escherichia coli. The recombinant form of hG-CSF is capable of supporting neutrophil proliferation in a CFU-GM assay. In addition, recombinant hG-CSF can support early erythroid colonies and mixed colony formation. Competitive binding studies done with 125I-labeled hG-CSF and cell samples from two patients with newly diagnosed human leukemias as well as WEHI-3B(D+) cells showed that one of the human leukemias (ANLL, classified as M4) and the WEHI-3B(D+) cells have receptors for hG-CSF. Furthermore, the murine WEHI-3B(D+) cells and human leukemic cells classified as M2, M3, and M4 were induced by recombinant hG-CSF to undergo terminal differentiation to macrophages and granulocytes. The secreted form of the protein produced by the bladder carcinoma cell line 5637 was found to be O-glycosylated and to have a molecular weight of 19,600.     

The role of CCR7 in TH1 and TH2 cell localization and delivery of B cell help in vivo

Subsets of murine CD4+ T cells localize to different areas of the spleen after adoptive transfer. Na?ve and T helper 1 (TH1) cells, which express the chemokine receptor CCR7, are home to the periarteriolar lymphoid sheath, whereas activated TH2 cells, which lack CCR7, form rings at the periphery of the T cell zones near B cell follicles. Retroviral transduction of TH2 cells with CCR7 forces them to localize in a TH1-like pattern and inhibits their participation in B cell help in vivo but not in vitro. Thus, differential expression of chemokine receptors results in unique cellular migration patterns that are important for effective immune responses.