Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have cloned and sequenced a cDNA encoding gp34, a novel glycoprotein expressed in cells bearing human T-cell leukemia virus type I (HTLV-I). HTLV-I has a trans-acting transcriptional activator, p40tax, that is thought to be implicated in leukemogenesis through the activation of cellular enhancers. With a subline (JPX-9) of the human T-cell line Jurkat, in which p40tax is inducible, gp34 was shown to be of cellular origin and to be transcriptionally activated by p40tax. It was also demonstrated that two species of mRNA are generated from one copy of the gp34 gene and that these mRNAs encode the identical gp34 product and differ in the 3' untranslated region. Analysis of the deduced amino acid sequence of gp34 showed that it lacks typical signal peptides; however, it has a hydrophobic stretch for membrane anchoring and four possible N-linked glycosylation sites at the carboxy-terminal portion, indicating that it belongs to the family of membrane proteins whose carboxy-terminal portion protrudes out of the cell. The gp34 gene displayed relatively delayed induction compared with other genes activated by p40tax. Taken together with the observation of the dependence of gp34 expression on HTLV-I p40tax, unlike other p40tax-dependent genes such as those for the interleukin-2 receptor alpha chain and c-fos, which are expressed or induced under physiological conditions, we predict that the mechanism involved in the induction of gp34 expression by p40tax is distinct from and more intricate than those for the previously characterized genes.
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PMID:Molecular cloning and characterization of a novel glycoprotein, gp34, that is specifically induced by the human T-cell leukemia virus type I transactivator p40tax. 199 93

The kappa B sequence (GGGACTTTCC) binds a factor, NF-kappa B, that is constitutively found in its functional, DNA binding form only in B lymphocytes. A factor with apparently indistinguishable sequence specificity can be induced in many other cell types, where it is used to regulate inducible gene expression. For example, kappa B-related sequences have been shown to be important for the transcription of a few inducible genes, such as the interleukin 2 receptor alpha-chain gene and the beta-interferon gene. However, these genes are not constitutively active in B lymphocytes, suggesting that other regulatory mechanisms must play a role in determining the patterns of expression. We have investigated the constitutive and inducible transcriptional activity mediated by five kappa B-related sequence elements in two different cell types. We show that in S194 plasma cells the activity of each element correlates well with the relative affinity of B-cell-derived NF-kappa B for that element. This leads to significantly lower transcription enhancement by sites derived from the interleukin 2 receptor or T-cell receptor genes in S194 cells. However, in either EL-4 (T) cells or S194 cells, both lower-affinity sites can be significantly induced by the tax gene product of human T-cell leukemia virus type I, showing that NF-kappa B activity can be modulated even in a B-cell line that constitutively expresses this factor.
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PMID:Comparison of constitutive and inducible transcriptional enhancement mediated by kappa B-related sequences: modulation of activity in B cells by human T-cell leukemia virus type I tax gene. 200 51

Disseminated erythematous papules and plaques developed in a 60-year-old man 3 years before the appearance of neurologic manifestations. A biopsy specimen of the plaque revealed Pautrier's microabscess and a dense mononuclear cell infiltration with atypical convoluted nuclei in the papillary dermis. These cells were helper/inducer T lymphocytes that expressed the interleukin 2 receptor. The patient's white blood cell count was normal, but 1% atypical lymphocytes and a high titer of anti-human T-lymphotropic virus (HTLV)-I antibody were detected in his serum. A smoldering type of adult T-cell leukemia was diagnosed. While he was being treated with PUVA, a gait disturbance developed. A high titer of anti-HTLV-I antibody, characteristic of HTLV-I-associated myelopathy, was demonstrated in his cerebrospinal fluid.
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PMID:HTLV-I-associated myelopathy in a patient with adult T-cell leukemia. 203 44

We have proposed a multichain model for the high-affinity interleukin-2 (IL-2) receptor involving two IL-2-binding peptides, a 70/75 kilodalton (kD) and a 55 kD, reactive with the anti-Tac monoclonal antibody, which are associated in a receptor complex. With the use of coprecipitation analysis, radiolabeled interleukin-2 cross-linking procedures, and flow cytometric resonance energy transfer measurements, a series of additional peptides of molecular weight 22,000, 35,000, 40,000, 75,000 (non-IL-2 binding), 95,000-105,000, and 180,000 has been associated with the two interleukin-2-binding peptides. In contrast to resting T cells, the abnormal T cells of patients with human T-cell lymphotropic virus I-associated adult T-cell leukemia, patients with select autoimmune disorders, and individuals rejecting allografts express the Tac peptide (p55) of the IL-2 receptor. To exploit this difference in Tac antigen expression, we have initiated therapeutic trials using unmodified anti-Tac, conjugates of anti-Tac with truncated Pseudomonas exotoxin PE-40, interleukin-2-truncated toxin fusion proteins, and alpha- and beta-emitting isotopic chelates of anti-Tac. Furthermore, by genetic engineering humanized hyperchimeric anti-Tac molecules have been prepared in which the molecule is entirely human IgG1, except for the small complementarity-determining regions that are retained from the mouse antibody. This "humanized" antibody manifested the ability to perform antibody-dependent cellular cytotoxicity absent in the original mouse monoclonal. The clinical application of anti-interleukin-2 receptor-directed therapy represents a new perspective for the treatment of certain neoplastic diseases and autoimmune disorders and for the prevention of allograft rejection.
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PMID:Lymphokine receptor-directed therapy: a model of immune intervention. 208 86

Cell line PER-315 was established from a bone marrow sample of a 5-year-old boy diagnosed with acute lymphoblastic leukemia (ALL) of T cell lineage. PER-315 cells express the surface markers present on immature thymocytes, express cytoplasmic CD3, and their growth is dependent on interleukin-2 (IL-2). Hence, this cell line represents a new type of precursor T-ALL, which is IL-2 dependent. Assessment of the T cell receptor rearrangements confirmed the clonal origin of cell line PER-315, and comparison with the patient's leukemia cells revealed an identical pattern. PER-315 cells show strong cytotoxicity against cell lines K562, Daudi, and Molt-4. They do not express the Tac antigen, but bind IL-2 with a Kd of 650 pM. Since PER-315 cells represent immature thymocytes, this new cell line may provide a model to further investigate the IL-2 receptor structure present at this stage of T cell differentiation.
Leukemia 1990 Apr
PMID:Characterization of an interleukin-2 dependent human leukemic cell line, PER-315, with an immature T cell phenotype which does not express the tac antigen. 216 20

Anti-Tac(Fv)-PE40 is a recombinant single-chain immunotoxin containing the heavy and light variable regions of the anti-Tac monoclonal antibody fused to a mutant form of Pseudomonas exotoxin (PE). Anti-Tac binds to the p55 subunit of the human interleukin 2 (IL-2) receptor, and anti-Tac(Fv)-PE40 kills human or monkey cell lines that contain either the intact IL-2 receptor or its p55 subunit alone. To assess the usefulness of anti-Tac(Fv)-PE40 in treatment of IL-2 receptor-positive leukemia, we tested peripheral blood mononuclear cells from six patients with adult T-cell leukemia. In each of the six patients, anti-Tac(Fv)-PE40 was extremely cytotoxic to the malignant cells. Metabolic activity and sensitivity of the fresh cells improved when a small amount of IL-2 (10 units per ml) was present during incubation. The toxin concentration necessary to inhibit protein synthesis by 50% after 16-hr incubation of cells with immunotoxin varied from 1.6 to 16 ng/ml (2.5-25 x 10(-11) M). In every case, binding was by means of the Tac antigen because anti-Tac(Fv)-PE40 cytotoxicity was prevented by adding excess anti-Tac antibody. Moreover, anti-Tac alone or an inactive mutant of anti-Tac(Fv)-PE40 without ADP-ribosylation activity had very little cytotoxic activity. Peripheral blood mononuclear cells from normal controls, from a patient with Tac-negative leukemia, and from adult T-cell leukemia patients without significant peripheral blood involvement were not sensitive to anti-Tac(Fv)-PE40. These results indicate that anti-Tac(Fv)-PE40 is a potent cytotoxin against adult T-cell leukemia cells in vitro and warrants clinical testing.
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PMID:The recombinant immunotoxin anti-Tac(Fv)-Pseudomonas exotoxin 40 is cytotoxic toward peripheral blood malignant cells from patients with adult T-cell leukemia. 223 41

Expression of the pX gene products (p40tax, p27rex and p21X-III) of human T cell leukemia virus type 1 (HTLV-1), which is known to be a causative agent of adult T cell lymphoma/leukemia, induces expression of the interleukin-2 receptor alpha chain (IL-2R alpha) on infected T cells. Comparison of IL-2R alpha promoter activities has revealed that the transcriptional activation of the promoter alone cannot explain the large numbers of IL-2R alpha expressed on HTLV-1 infected cells. We found that the rates of the IL-2R alpha mRNA degradation were greatly reduced in pX-positive cells as compared with pX-negative cells. Simultaneous transfection of the expression vector plasmid containing IL-2R alpha cDNA and similar plasmids containing various pX sequences showed that p27rex elongated the half life of IL-2R alpha mRNA. As p27rex did not affect the transport of the IL-2R alpha mRNA from nucleus to cytoplasm, prolongation of the IL-2R alpha mRNA half life by p27rex is ascribed to stabilization of the mRNA. Experiments using deletion mutants and chimeric constructs of the IL-2R alpha cDNA demonstrated that the coding sequence but not the 5' or 3' untranslated region of the IL-2R alpha mRNA sequence is responsible for its protection by p27rex.
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PMID:HTLV-1 p27rex stabilizes human interleukin-2 receptor alpha chain mRNA. 224 70

We measured blood concentrations of tumor necrosis factor (TNF), interleukin-1 beta (IL 1-beta), soluble interleukin 2 receptor (s-IL 2r), and interferon alpha (IFN alpha) in 30 patients with disseminated intravascular coagulation (DIC) and compared the results to those of 25 patients without DIC. Plasma levels of TNF, IL 1-beta, and s-IL 2r were higher in patients with DIC than in those without DIC. In one case of acute promyelocytic leukemia, plasma levels of TNF and IL-1 beta increased at the onset of DIC but decreased upon DIC improvement. These findings suggest that activation of the immune system is involved in the development of DIC. However, these concentrations were not markedly increased in patients with leukemia, although blood TNF and s-IL 2 r were markedly elevated in patients with solid cancers. Especially in patients with solid cancers, hyperactivation of the immune system may cause an increase in blood TNF and IL-1 beta and the development of DIC.
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PMID:[Elevated levels of cytokines in plasma from patients with disseminated intravascular coagulation]. 225 53

The Mr 55,000 interleukin 2 receptor peptide (Tac; CD25) is not expressed by normal resting T-cells but is markedly up-regulated in adult T-cell leukemia and other malignancies, as well as on T-cells activated in normal immune, autoimmune, allograft, and graft-versus-host settings. Anti-Tac is a mouse monoclonal antibody directed against the Tac peptide. Our prior attempts to use this antibody in humans for antitumor therapy and immune regulation have been limited by weak recruitment of effector functions and neutralization by antibodies to mouse immunoglobulins. To circumvent these difficulties, we prepared several chimeric "humanized" anti-Tac antibodies by genetic engineering, including one "hyperchimeric" antibody (anti-Tac-II) in which the molecule is human except for the small hypervariable segments of the complementarity-determining regions retained from the mouse antibody. These constructs maintain high affinities for antigen and abilities to block T-cell activation and demonstrate new capabilities to perform antibody-dependent cell-mediated cytotoxicity, absent in the mouse anti-Tac. Hence, humanized antibodies have been developed to a tumor-associated antigen and activated T-cell marker with significant features that offer new therapeutic possibilities for select neoplastic and immune disorders.
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PMID:Anti-Tac-H, a humanized antibody to the interleukin 2 receptor with new features for immunotherapy in malignant and immune disorders. 240 13

A human eosinophilic leukemia cell line, designated as EoL, was established from the peripheral blood of a patient with Philadelphia chromosome-negative eosinophilic leukemia (EL). The EoL cell line grows in single cell suspension with a doubling time of 48 hours for about one year. The reactivity of these cells was tested with a panel of monoclonal antibodies; they were found to express surface IA antigen, myeloid antigen (IF10, MY9) and membrane receptors for interleukin 2 (IL-2, Tac antigen). Under standard culture conditions, a small percentage of cells having more typical eosinophilic characteristics was present. These cells had cytoplasmic granules and were positive for Luxol-fast-blue and eosinophil peroxidase. Under culture conditions to induce the maturation of myeloid cells, such as alkaline medium or addition of dimethyl sulfoxide (DMSO), the frequency of cells with typical eosinophilic features increased to about 40%. In addition, cytogenetic studies showed that cultured cells and original leukemic blasts presented similar chromosome abnormalities. EoL seems to be a unique leukemic line committed to the eosinophilic lineage and can provide a useful in vitro model for the study of malignant eosinophilic properties.
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PMID:Establishment and characterization of a new human eosinophilic leukemia cell line. 241 85


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