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)

The human T leukemia line Jurkat maintains functional characteristics of normal T cells in responding to inducing stimuli by the release of interleukin 2 (IL 2). Presence of a phorbol ester during stimulation eliminated the requirement for specialized accessory cells in the response to cell mitogenic agents such as the lectin concanavalin A or treatment with neuraminidase and galactose oxidase. Antibodies directed against the T cell receptor-associated antigen T3 served as efficient stimuli, especially if aided by agents that cross-link immunoglobulin, indicating that a triggering signal is received by a T cell via aggregation of its antigen receptor complex. A Burkitt lymphoma cell line, Raji, was found to selectively trigger Jurkat cells, suggesting the ability of those cells to respond to certain foreign stimuli. The Jurkat cell line has been instrumental in the purification of IL 2 and cloning of the corresponding gene. Our data suggest it can also serve as a useful model for induction of T cell responses.
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PMID:Analysis of human T lymphocyte activation in a T cell tumor model system. 387 19

The gibbon leukemia cell line MLA 144 differs from every other T-lymphocyte line in that it constitutively makes interleukin 2 (IL-2) (also called T-cell growth factor) without stimulation by antigen, lectin, or tumor promoters. Previous work in which glucocorticoids were used to inhibit IL-2 production has indicated that proliferation of this cell line is dependent upon endogenously produced IL-2. We have found that the MLA 144 cell line has a copy of the gibbon leukemia virus inserted into the 3' nontranslated region of the IL-2 gene. This integration event produces a composite mRNA made up of the protein coding sequences of the IL-2 gene transcript but incorporating the viral long terminal repeat (LTR) in the 3' nontranslated region of the mRNA. This composite mRNA transcript uses the polyadenylylation signal in the viral 5' LTR and incorporates the viral transcriptional control regions. The integration event must involve only one allele of the IL-2 gene, since transcripts essentially identical to normal human IL-2 mRNA are also produced in cloned sublines of MLA 144. That the viral LTR contains a 94-base-pair repeat reminiscent of enhancer sequences in several viruses suggests that the integration of the viral LTR at the 3' end of the IL-2 gene is responsible for the constitutive production of IL-2 in the MLA 144 cell line.
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PMID:A viral long terminal repeat in the interleukin 2 gene of a cell line that constitutively produces interleukin 2. 387 7

Ricin-resistant variants of the SH9 T-cell line were selected after growth of this line in medium containing toxic amounts of ricin, a lectin derived from Ricinus communis. The ricin-resistant SH9 lines, SH9.R0 and SH9.R1, were demonstrated to be deficient in cell surface ricin-binding sites, but otherwise had the cellular phenotype of SH9 cells. Ricin-resistant T-cell hybridomas were prepared by fusion of SH9.R0 and SH9.R1 with activated T-lymphocytes. The presence of ricin in the selection medium rapidly killed unfused T-lymphocytes and prevented cell transformation by human T-cell leukaemia virus type 1 (HTLV-1) which is shed by the SH9.R0 and SH9.R1 cells. This ensured that the cells growing out were indeed hybridomas. Ricin-resistant T-cell hybridomas were characterised and also shown to lack cell surface receptors for ricin. Analysis of T-cell surface markers indicated that the T-cell hybridomas could be the result of fusions between SH9.R1 cells and T-helper lymphocytes or T-suppressor lymphocytes. All of the T-cell hybridomas prepared in this study spontaneously produced interferon gamma (IFN gamma).
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PMID:Ricin-resistant human T-cell hybridomas producing interferon gamma. 392 Mar 24

Cell surface alteration was studied in a subline of murine lymphocytic leukaemia resistant to the broad-spectrum anticancer agent adriamycin (P388/ADR) employing concanavalin A(Con A)-induced agglutination and rearrangement of lectin receptors. Con A induced more agglutination of P388/ADR when compared to the drug-sensitive parental cell line (P388/S). Studies on the redistribution of Con A and Ricinus communis agglutinin-I revealed a high percentage of P388/ADR showing internalized fluorescence, while a majority of P388/S displayed a uniform distribution of fluorescence on the cell surface.
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PMID:Cell surface alterations in murine leukaemia P388 adriamycin-resistant cells: studies on lectin-induced agglutination and rearrangement of lectin receptors. 403 47

Revertants of Kirsten sarcoma virus transformed nonproducer BALB/3T3 cells (KA31 cells) were isolated after exposing the transformed cells to 5-fluorodeoxyuridine at high cell density, or when suspended in methylcellulose. Revertants were also isolated by treating KA31 cells with the lectin, concanavalin A, which is manyfold more toxic to transformed cells than for normal cells. The revertants resemble BALB/3T3 cells in their morphology and growth characteristics in that they have a low saturation density, fail to grow in 1% calf serum or when suspended in methylcellulose, and cease to synthesize DNA after reaching their saturation density. Infection by murine leukemia virus rescues Kirsten sarcoma virus from only the concanavalin-A-selected variants, though all the revertants are susceptible to infection by leukemia virus. The concanavalin A revertants also become transformed after infection with murine leukemia virus. All the revertants can be transformed by Kirsten sarcoma virus but not by simian virus 40.
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PMID:Selection of revertants of Kirsten sarcoma virus transformed nonproducer BALB-3T3 cells. 436

Interleukin-2 (IL-2) is a lymphokine synthesized by some T cells following activation. Resting T cells do not express IL-2 receptors but receptors are rapidly expressed on T cells following the interaction of antigens, mitogens, or monoclonal antibodies with the antigen specific T-cell receptor complex. Using anti-Tac a monoclonal antibody that recognizes the IL-2 receptor, the receptor has been purified. The receptor is a 33 kdalton peptide that is post-translationally glycosylated to a 55 kdalton mature form. Mature receptors contain both N-linked and O-linked sugars and are both sulfated and phosphorylated. Using an oligonucleotide probe, based on the N-terminal amino acid sequence, cDNAs encoding this receptor have been cloned, sequenced and expressed. The addition of anti-Tac to in vitro culture systems blocks the IL-2 induced DNA synthesis of IL-2 dependent T-cell lines and inhibits soluble auto- and alloantigen induced T-cell proliferation. Furthermore, it prevents the generation of cytotoxic and suppressor effector T cells. The anti-receptor antibody also inhibits lectin stimulated immunoglobulin synthesis and the sequential expression of late appearing activation antigens on T cells. Normal resting T cells and most leukemic T-cell populations do not express IL-2 receptors however the leukemic cells of all patients with human T-cell leukemia/lymphoma virus (HTLV-I) associated, adult T-cell leukemia (ATL) examined expressed the Tac antigen. In HTLV-I infected cells the 42 kdalton long open reading frame (LOR) protein encoded in part, by the pX region of HTLV-I may act as a transacting transcriptional activator that induces transcription of the IL-2 receptor gene thus providing an explanation for the constant association of HTLV-I infection of lymphoid cells and IL-2 receptor expression. The constant display of large numbers of IL-2 receptors which may be aberrant in the ATL cells may play a role in the uncontrolled growth of these leukemic T cells. Patients with the Tac positive ATL are being treated with an anti-Tac monoclonal antibody directed towards this growth factor receptor.
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PMID:Interleukin-2 receptor expression in retrovirus associated adult T-cell leukemia. 610 Jun 44

A new procedure for enrichment of marrow precursors and removal of T lymphocytes from large volumes of human bone marrow, involving initial differential agglutination of T lymphocytes and mature marrow elements with soybean agglutinin, followed by rosetting with sheep red blood cells, was used to fractionate marrow cells from an HLA-A, B, DR non-identical, MLC non-reactive, paternal donor for transplantation into an infant with acute leukaemia. This transplant became completely engrafted and resulted in full recovery of normal, donor-derived haematopoietic function without graft-versus-host disease, sustained for 11 weeks after transplantation, at which time the patient's leukaemia recurred. Subsequently, the patient received chemotherapy and achieved a remission with regeneration of normal marrow cells of donor origin. The patient's course demonstrated the potential of lectin-separated marrow grafts to restore durable haematopoiesis, without graft versus host disease, in a lethally irradiated allogeneic host.
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PMID:Transplantation for acute leukaemia with HLA-A and B nonidentical parental marrow cells fractionated with soybean agglutinin and sheep red blood cells. 611 10

Beta 2-microglobulin-bound T-cell membrane components containing both human TL-like antigens and HLA(A, B, C) antigens were partially purified from Renex 30-solubilized membrane material of cells of a human T-cell-type leukemia cell line, HPB-ALL. The radioiodinated preparation was subjected to limited papain digestion; the HLA(A, B, C) antigens split, whereas a large portion of the human TL-like antigens remained intact. The antigen molecules were recovered by lentil-lectin affinity chromatography and separated by gel filtration on the basis of the induced difference in molecular size. The human TL-like-antigen preparation thus obtained was essentially free of HLA(A, B, C) antigens. The human TL-like antigens were immunospecifically precipitated and the component polypeptide, heavy and light, chains were separated by acid dissociation followed by gel filtration. The component chains were compared with the corresponding chains of HLA(A, B, C) antigens obtained similarly from the same HPB-ALL cells with respect to their fragmentation patterns on chemical or enzymatic cleavage. The results provided convincing evidence for the identity of the light chains of human TL-like antigens and HLA(A, B, C) antigens, and also evidence suggesting the presence of substantial differences in the fundamental structure of the heavy chains of human TL-like antigens and HLA(A, B, C) antigens.
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PMID:Separation and comparison of human TL-like antigens and HLA(A, B, C) antigens expressed on cultured T cells. 616 35

Some factors influencing the interaction in vitro between dimethylsulphoxide-induced Friend leukaemia erythroblasts (IFLE) and syngeneic mouse peritoneal macrophages (M phi) have been investigated. Desialation of erythroblasts by treatment with neuraminidase resulted in a significant increase in their association with and ingestion by M phi. In addition, the interaction with M phi of both neuraminidase-treated and untreated IFLE was found to be influenced by a heat-stable serum factor. gamma-globulin markedly enhanced the weak IFLE-M phi interaction which occurred at low serum concentration suggesting that the heat-stable factor may be an immunoglobulin. Desialation of the IFLE-rendered them agglutinable by peanut lectin which was used as a probe for neuraminidase-induced membrane changes. By contrast, cycloheximide treatment of IFLE which also enhances their interaction with M phi, did not result in the exposure of receptors for this lectin. It is proposed that both desialation and cycloheximide treatment of IFLE lead to secondary alterations in their membrane structure which renders them recognizable by M phi.
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PMID:Interaction between erythroblasts and macrophages in vitro: effect of neuraminidase-treatment of erythroblasts and the role of serum factors. 619 4

The presence and the sugar specificity of membrane lectins on the cell surface of mouse L1210 leukemia cells were demonstrated by using various neoglycoproteins (glycosylated serum albumin) substituted with fluorescein or methotrexate. Neoglycoproteins were prepared by reaction of glycosidophenylisothiocyanates with bovine serum albumin. The binding of neoglycoproteins to L1210 cells depends on the nature of the carried sugar and on the number of bound sugar residues per neoglycoprotein molecule. The best results were obtained with fucosylated serum albumin containing 25 +/- 5 residues of fucose. The amount of cell-associated fluorescein-labeled neoglycoproteins was several fold higher at 37 degrees C than at 4 degrees C suggesting a specific endocytotic process. The membrane lectin-mediated endocytosis was further demonstrated by showing that the cell-associated fluorescence upon cell incubation in the presence of fluorescein-labeled neoglycoproteins at 37 degrees C increased several fold after addition of monensin, a proton/sodium ionophore known to raise the pH of endosomes and lysosomes. The analysis of fluorescein-labeled neoglycoproteins association to the L1210 cells were achieved by quantitative flow cytofluorometry after standardization with calibrated polystyrene sulfonate beads carrying various amounts of 1-(fluoresceinylthioureido)-4,8-diazalicosane. In addition, the cytotoxicity of neoglycoprotein-bound methotrexate was shown to be related to the presence and to the nature of the carried sugar: fucosylated serum albumin was shown to be the most efficient neoglycoprotein carrier, and to have a cytotoxicity close to that of anti L1210 cell IgM monoclonal antibody carrying methotrexate.
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PMID:Uptake of neoglycoproteins via membrane lectin(s) of L1210 cells evidenced by quantitative flow cytofluorometry and drug targeting. 624 Mar 1


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