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)

RNA-directed DNA polymerase (reverse transcriptase) from leukocytes of individual leukemic patients can be grouped by velocity gradient analyses into two distinct classes, a low-molecular-weight (LMW) class of approximately 70,000 and a high-molecular-weight (HMW) class of 130,000 to 140,000. The reverse transcriptases from mammalian type-C viruses have with one exception (see text) been isolated as enzymes with molecular weights of 70,000. In this study, the reverse transcriptase from extracellular gibbon ape leukemia virus was also isolated only as the LMW class. However, the enzyme from gibbon virus-producing cells was isolated partially in the HMW form; this form was converted completely to the LMW form by treatment with 0.5 M KC1 and 0.5% Triton X-100 and could be re-converted to the HMW form by lowering the KC1 and Triton X-100 concentrations. A similar conversion from a HMW form to a LMW form was demonstrated with enzyme from human leukemic cells. The LMW form of the human and gibbon ape cellular enzymes utilized synthetic primer-templates in a similar fashion to viral enzyme, and this form was strongly inhibited by antisera (IgG) to reverse transcriptase from simian (woolly monkey) type-C virus. The HMW form of both enzymes utilized synthetic primer-templates less efficiently than the LMW form, and was resistant to inhibition by antipolymerase IgG of simian type-C virus. The HMW form of the cellular reverse transcriptases transcribed viral 70S RNA in the absence of synthetic primer relatively more efficiently than did the extracellular viral form. These data suggest that the HMW form is due in part to aggregation of the LMW form and in part to a cellular factor(s) which may affect both the form and function of intracellular reverse transciptase.
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PMID:RNA-directed DNA polymerase from human leukemic blood cells and from primate type-C virus-producing cells: high- and low-molecular-weight forms with variant biochemical and immunological properties. 4 50

By means of gel filtration and isoelectric focusing, an antigen of the bovine C-type leukemia virus was isolated in a highly purified form from extracts of infected cells. The antigen has a molecular weight of approximately 25,000 daltons and an isoelectric point of 6.4 to 6.6. In immunodiffusion experiments, the antigen forms a line of identity with an antigen extracted from highly purified bovine C-type leukemia virus by treatment with ether or Triton X-100. As determined by immunodiffusion analyses, the bovine C-type leukemia virus antigen does not have antigenic determinants in common with the murine or feline leukemia viruses, the foamy-like bovine syncytia virus, or the Mason Pfizer monkey virus.
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PMID:Isolation and characterization of an antigen of the bovine C-type virus. 5 93

An experimental procedure for detecting and characterizing tumor-associated, virion, and histocompatibility antigens has been developed. The method takes advantage of the high resolution that proteins, solubilized by Triton X-100 and reduced, display after sodium dodecyl sulfate gel electrophoresis. The antigens can be detected as distinct molecular weight species by a highly sensitive inhibition of cytotoxic reaction. When coupled to the lactoperoxidase-catalyzed iodination of intact cells, the procedure permits the determination of externally exposed antigens. In the present study, the method has been applied to the Moloney leukemia virus-induced YAC lymphoma cells of strain A mice, which express a Moloney leukemia virus-determined cell surface antigen (MCSA) in addition to the type C viral proteins gp71, p30, p15, p15(E), p12, and p10. MCSA was identified as an exposed surface protein distinct in size and antigenic determinants from the major envelope and core protein of Moloney leukemia virus and the histocompatibility antigens. Multiple molecular weight species possessing antigenic determinants for MCSA, gp71, and H-2(a) have been detected. These results provide direct confirmation that MCSA is unrelated to the known virion structural proteins or to the H-2(a) antigen. This method should permit the direct identification and molecular weight characterization of any antigen whose determinants are not solely dependent on a complex quaternary structure and for which serological reagents are available.
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PMID:Moloney leukemia virus-induced cell surface antigen: detection and characterization in sodium dodecyl sulfate gels. 7 31

Moloney leukemia virus activated both the classical and alternative pathways of human complement. About 500,000 virions were required to detect activation of the classical pathway whereas 5,000 times as many virions were necessary to initiate the alternative pathway, indicating that in this system only the former is of biological significance. Disruption of the virus with Triton X-100 destroyed its ability to initiate the alternative pathway without affecting its ability to activate the classical pathway. After ultracentrifugation of disrupted virus the active component could be recovered in the supernate and was isolated by isoelectric focusing in granulated gels. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic and analysis and cyanogen bromide digestion studies revealed that the activity resided in a methionine-containing protein having a pI of 7.5 and a molecular weight of approximately equal to 15,000 daltons. The purified protein interacts strongly with Clq and efficiently activates Cl. RNase and lipolytic enzymes had no effect on the isolated protein but incubation with trypsin resulted in loss of activity. Enzymatic digestion studies of surface-labeled virus indicate that the active protein is a viral membrane protein. On the basis of these results it is concluded that the complement receptor of Moloney leukemia virus is the surface protein p15E.
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PMID:Lysis of oncornaviruses by human serum. Isolation of the viral complement (C1) receptor and identification as p15E. 63 50

The possible existence of several species of DNA-dependent DNA polymerases in mammalian cells in addition to those 2 polymerases which are the smaller enzyme from nucleus and larger one from cytoplasm each having distinct characteristics, have been reported recently. In order to examine the heterogeneity of DNA polymerases in murine leukemia L1210 cells and to characterize their general properties, we have attempted to separate the DNA polymerase activities from L1210 cells. By diethylaminoethyl (DEAE)-cellulose chromatography (0.2 M-1M KCl) of the whole cell extract from L1210 solubilized by 1% Triton X-100 and 0.5 mM ethylenediaminetetraacetate (EDTA), 4 fractions with DNA-dependent DNA polymerase activities were obtained and designated as DD-1, DD-2, DD-3, and DD-4 for eluents with each corresponding concentration of 0.2, 0.3, 0.5, and 0.7 M KCl, respectively. They were distinguishable in properties such as template preference, divalent cation requirement, DNase sensitivity, isoelectric point (pI) and the behavior on the phosphocellulose chromatography. DD-1 preferred native DNA as template exhibiting similar characteristic as nuclear polymerase with low molecular weight and insensitivity to SH-inhibitors. DD-2, DD-3, and DD-4 utilized activated DNA most efficiently, while activity of DD-3 increased even in the presence of DNase 1 under the condition where the others were completely inhibited. Distribution of DNA polymerase activities in the cells is discussed briefly.
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PMID:Separation and properties of DNA polymerase from murine leukemia L1210 cells. 117 38

Immunoglobulins derived from sera containing anti-antiidiotypic antibodies (Ab2) generated in renal transplant recipients after OKT3 monoclonal antibody therapy, as reported in our previous study (1), have now been proved to bind to several bands of T cell membrane lysates (TCML) in immunoblotting analyses ranging in molecular weight from 40 to 55 KD. These sera also blocked the expression of the ligand binding to WT31 in flow cytometry. WT31 is a MAb that recognizes a common determinant on the T cell receptor (TCR). Immunoglobulins from these sera suppressed the activation of normal peripheral blood T lymphocytes (PBT) induced by OKT3. All patients (7/32) who developed this Ab2 had distinct culture-proved cytomegaloviral infections. In further immunoblotting studies, alpha F1, another MAb recognizing the framework of the TCR alpha chain, more deeply inserted in the T cell membrane, also showed binding to protein bands of cytomegalovirus pellet lysates derived from virus-infected embryonic fibroblasts. In addition, alpha F1 showed positive binding to several ligands in the membrane lysate of CMV-infected, but not noninfected MRC-5 cells. An anti-CMV MAb recognizing late nuclear antigen (LAb), also strongly bound to a approximately 50 KD band of TCML and several bands (approximately 34, approximately 40, and approximately 50 KD) of H33HJAJ1 (human T leukemia) cell lysate. Furthermore, alpha F1 immunoprecipitated a approximately 96 KD ligand of CMV-infected MRC5 lysate that had the same electrophoretic mobility as one of the proteins precipitable with LAb. Both LAb and alpha F1 also showed positive binding to paraformaldehyde-fixed and Triton X-100-permeabilized PBT in flow cytometry. Sera containing Ab2 blocked alpha F1 binding to acetone-fixed cytofuged PBT preparations on slides. Moreover, both alpha F1 and LAb inhibited mitogen-stimulated lymphocyte activation in vitro. These data support the notion that T cell functional abnormalities associated with CMV infection observed after treatment of transplant recipients with anti-T cell monoclonals might be caused by binding to T cell ligands by a variety of crossreacting human Igs operative in a regulatory network. Confirmatory evidence is the effect of MAbs generated against CMV virion epitopes crossreacting with T cell ligands, and vice versa.
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PMID:Evidence that antibodies to cytomegalovirus and the T cell receptor (TCR)/CD3 complex may have common ligands. 184 53

P48 is a recently described 48-kDa differentiation-inducing cytokine isolated from the culture medium of the human leukemia line Reh. P48 induces differentiation and cytolytic activity in the promyelocytic cell line HL-60, and stimulates the release of TNF-alpha and IL-1 from peripheral blood monocytes. In further studies designed to examine the biosynthesis and function of P48, surface immunofluorescence flow cytometry analysis as well as 125I surface labeling and immunoprecipitation, revealed the presence of P48 on the surface of Reh cells. Triton X-114-treated Reh cells were partitioned into detergent and aqueous phases and separated by SDS-PAGE. Western blot analysis revealed that P48 partitioned exclusively into the detergent phase, suggesting an integral membrane association. Reh cells fixed with paraformaldehyde, but not K562 or P815, were able to stimulate the release of TNF-alpha from peripheral blood monocytes in a manner similar to that of secreted P48. Isolated plasma membranes from Reh cells could also stimulate TNF-alpha release. This TNF-alpha-releasing activity could be removed from detergent solubilized Reh membranes by immunoaffinity chromatography on an anti-P48 column. This study suggests that, in addition to being secreted into the culture medium, P48 is expressed on the surface of Reh cells in a biologically active form. The membrane form of P48 may be 1) a final maturation step before secretion or 2) a cell membrane-associated form that may be analogous to the membrane forms of TNF-alpha and IL-1.
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PMID:Differentiation-inducing cytokine P48 exists in a membrane-associated form. 186 Oct 78

An enzyme-linked immunosorbent assay (ELISA)-based glycosyltransferase assay has been used to measure UDP-Gal:N-acetylglucosamine beta-1,4-galactosyl-transferase (EC 2.4.1.38) activity in detergent extracts of chinese hamster ovary (CHO) cells. LEC11 cells (a mutant of the CHO cell line, Pro -5), which are known to express a complex array of carbohydrate structures, were used to develop the assay for use with whole cell extracts. A detergent-solubilized preparation of the enzyme from whole cells was used to convert the substrate, lactotriglycosylceramide, to the product, neolactotetraglycosylceramide. The monoclonal antibody, 1B2, which specifically binds to the Gal beta 1-4GlcNAc epitope, was used in an ELISA to identify and quantify the product. The enzyme activity in the preparations was found to be similar to that obtained by conventional radioactive assay methods. The beta-galactosyltransferase found in LEC11 cell detergent extracts exhibited an absolute requirement for the nucleotide sugar and MnCl2. The activity of the enzyme was also strictly dependent on the presence of exogenous glycolipid acceptor. When Triton X-114 was used to solubilize the LEC11 beta-galactosyltransferase, activity was found in both the hydrophilic and the hydrophobic phases, suggesting the presence of two forms of the enzyme. The ELISA-based assay was used to compare beta-1,4-galactosyltransferase activity in detergent extracts of four CHO cell lines: Pro-5, Lec1, LEC11, and LEC12 and in detergent-solubilized microsomes from human leukemia cells. The results from this study demonstrate the utility of the ELISA-based assay for measuring glycosyltransferase activity in detergent-solubilized whole cells and microsome preparations.
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PMID:Measurement of beta-galactosyltransferase activity in cell extracts with an ELISA-based assay. 211 99

The authors studied accumulation of the fluorescent probe Hoechst 33258 in leukemia P 388 sensitive (P 388/0) and resistant to doxorubicin (P 388/DOX) cells. It was shown that intensity of fluorescence of the dye increased after binding with nuclear DNA during 25 min for both lines of the cells. Intensity of fluorescence was 40% greater in sensitive than resistant cells. If Triton X-100 was added no difference between two lines of the cell was observed. When doxorubicin was added to the cells with dye, the intensity of fluorescence decreased. It was suggested to use Hoechst 33258 for assessment extent doxorubicin accumulation in nuclei of the cells.
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PMID:[Comparative accumulation of the Hoechst 33258 fluorescent probe in leukemia P388 cells sensitive and resistant to doxorubicin]. 226 26

A simple, sensitive, and specific polymerase chain reaction (PCR) protocol for the detection of human immunodeficiency virus type 1 (HIV-1) is described. We have improved all three PCR steps: sample preparation, DNA amplification, and detection of the amplified product. Some of the improvements have been described previously, but they have never been combined into a complete PCR protocol. Peripheral blood mononuclear cells were lysed directly in a buffer containing sodium dodecyl sulfate, Triton X-100, and proteinase K. This crude cell lysate was amplified in a two-step PCR, first with outer primers and then with inner primers nested within the first primers. The PCR product was visualized by agarose gel electrophoresis and ethidium bromide staining. Thus, we avoided conventional DNA extraction as well as hybridization for the detection of the PCR product. The samples were analyzed with four sets of nested primers (JA4 through JA7, JA9 through JA12, JA13 through JA16, and JA17 through JA20) designed to amplify HIV-1 gag, env gp120, env gp41, and pol sequences, respectively. We were able to amplify HIV-1 sequences in all samples from 90 HIV-1-seropositive individuals with mostly mild symptoms. Of these individuals, 24 were negative in HIV-1 isolation and 9 were selected because they were infected by African and Haitian HIV-1 strains. Eighty-five (94%) individuals were positive with at least three of four primer sets. Samples from 26 healthy blood donors, as well as cells infected in vitro with human immunodeficiency virus type 2 and human T-cell leukemia virus type I, were negative in PCR, thus demonstrating the specificity of the amplification.
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PMID:Simple, sensitive, and specific detection of human immunodeficiency virus type 1 in clinical specimens by polymerase chain reaction with nested primers. 238 Mar 80


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