Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have examined for synergy between the IIIB strain of HIV-1 and Epstein-Barr virus (EBV) during infection of a homogeneous cell type. In order to obtain a cell population consisting of a homogeneous cell type, CD19-positive B lymphocytes were purified from human tonsils by flow cytometry. CD19-positive lymphocytes did not express detectable surface CD4 antigen. However, CD4 mRNA could be detected in CD19-positive lymphocytes by reverse transcription coupled to polymerase chain reaction and by dot blot hybridization using an antisense riboprobe. Transcription of CD4 mRNA in CD19-positive lymphocytes was suppressed by infection with the B95-8 strain of EBV and lost in B95-8-transformed lymphoblastoid cell lines. In contrast, the P3HR-1K strain of EBV had no effect on the level of CD4 mRNA. HIV-1 could infect CD19-sorted B cells as measured by accumulation of reverse transcriptase and syncytia induction after coculture with SupT1 cells. HIV-1 infection of CD19-bearing lymphocytes was blocked by OKT4a antibodies. The ability of HIV-1 to replicate in CD19-positive B lymphocytes declined following preinfection with B95-8 but not with P3HR-1K. These results as well as results with an EBNA-2 expression vector suggest that down-regulation of both CD4 mRNA and HIV-1 infection in human B cells is a function of EBV nuclear antigen EBNA-2. The fact that native CD19-positive B lymphocytes express sufficient CD4 receptor mRNA to allow HIV-1 infection strengthens the possibility that HIV-1 replication in B cells directly participates in AIDS pathogenesis. In addition, infection with EBV may modulate the ability of HIV-1 to infect and establish a latent infection in B lymphocytes in co-infected individuals.
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PMID:CD4 mRNA expression in CD19-positive B cells and its suppression by the Epstein-Barr virus. 750 84

We describe a new, rapid, sensitive, and reproducible method for examining gene expression of several cell specific surface cluster determinants, CD2, CD3-gamma, CD4, CD8-beta, CD14, CD19, CD20, CD23, and CD25-alpha, and terminal deoxynucleotidyl transferase which heretofore have been commonly detected by flow cytometry. The method presented uses the reverse transcriptase polymerase chain reaction (RT-PCR) to analyze CD gene expression in stable human cell lines, peripheral blood lymphocytes, bone marrow, and lymph node cells. Polymerase chain reaction products were quantitated by incorporation of radiolabeled nucleotide during PCR and the amount of nucleotide incorporated into DNA was measured by ion exchange filter chromatography. The usefulness of this methodology is demonstrated in an analysis of peripheral blood samples from a patient who presented with B cell deficiency. Results of analyses of peripheral blood samples from this patient by flow cytometry and RT-PCR are similar except that the increased sensitivity of RT-PCR permitted the detection of CD19, CD20, and CD23 in the blood samples of this patient who otherwise appeared to be lacking in all markers of B cell development.
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PMID:Detection of cell specific cluster determinant expression by reverse transcriptase polymerase chain reaction. 751 Jul 56

A new human monoclonal plasma cell line, designated UTMC-2, was established from the pleural effusion of a patient with immunoglobulin (Ig)A kappa-related multiple myeloma. The cultured cells were Epstein-Barr virus-negative and exhibited the morphological and ultrastructural features characteristic of plasma cells. Immunohistochemical analyses revealed the presence of cytoplasmic IgA kappa as well as the plasma cell-associated surface antigens CD38 and CD56. Other B-cell markers, including CD10, CD19, CD20, and HLA-DR, were absent. The UTMC-2 cells were interleukin (IL)-6 responsive: Co-culture with IL-6 increased IgA kappa synthesis and cell proliferation in a dose-dependent manner. In contrast, an IL-6 antisense oligonucleotide had an opposite effect. Although the UTMC-2 cells expressed IL-6 mRNA (as demonstrated by reverse transcriptase-polymerase chain reaction (RT-PCR)) and contained IL-6, the concentration of this cytokine in cell culture supernatants was less than that detectable by the enzyme-linked immunosorbent assay (ELISA) employed (i.e. <3 pg/ml). Further, cell growth was not inhibited by polyclonal or monoclonal anti-IL-6 antibodies. Flow cytometric analysis revealed that IL-6 receptors present on the surface of the UTMC-2 cells were not saturated with endogenous IL-6. Taken together, these results indicate that, in this human plasma cell line, IL-6 functions uniquely in an intracellular autocrine fashion to enhance Ig synthesis and cell growth. In this respect, the UTMC-2 cells represent a novel resource for further study of the role of IL-6 in the pathogenesis of multiple myeloma.
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PMID:Characterization of a novel interleukin-6 autocrine-dependent human plasma cell line. 752 62

A new human pre-B acute lymphoblastic leukemia cell line (KMO-90) was established from the bone marrow sample of a 12-year-old girl with acute lymphoblastic leukemia (ALL) carrying 1;19 chromosome translocation. KMO-90 cells expressed HLA-DR, CD10, CD19, and CD22 antigens. These cells had also cytoplasmic immunoglobulin lacking surface immunoglobulin, indicating that these had a pre-B phenotype. Chromosome analysis of this cell line showed 48, XX, +8, +19, t(1;19)(q23;p13). Southern blot analysis showed the same sized rearrangements of the E2A gene in KMO-90 cells as those in the original leukemic cells. By means of reverse transcriptase-polymerase chain reaction analysis, we detected E2A/PBX1 fusion transcripts in KMO-90 cells. KMO-90 is useful when studying the role of the 1;19 translocation in the etiology of pre-B ALL. Furthermore, we studied alterations of the p53 gene in this cell line by polymerase chain reaction, single-strand conformation polymorphism analysis. KMO-90 cells were identified to have a point mutation at codon 177 (CCC-->TCC) of the p53 gene, suggesting that alterations of the p53 gene may have an important role in the establishment of this cell line.
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PMID:Establishment of a new human pre-B acute lymphoblastic leukemia cell line (KMO-90) with 1;19 translocation carrying p53 gene alterations. 841 23

The syndecans comprise a family of integral membrane proteoglycans that regulate cell behaviors by binding to extracellular matrix and binding growth factors. In mouse blood cells, syndecan expression is restricted to cells of the B-cell lineage where it is expressed by pre-B cells and plasma cells, but is absent from circulating B cells. In the present study, we examined the expression, structure, and function of syndecan on human myeloma cell lines and myeloma patient bone marrow cells. On myeloma cells, syndecan is a small (modal relative molecular mass [M(r)] = 120 Kd) heparan sulfate proteoglycan localized at the cell surface. Syndecan was detected by immunodot blotting on 7 of 10 human myeloma cell lines and by reverse transcriptase polymerase chain reaction on 10 of 14 patient samples. Cell binding assays show that myeloma cells expressing syndecan bind to type I collagen via heparan sulfate chains, while those cell lines not expressing syndecan do not bind to collagen. Furthermore, the cell lines expressing syndecan were negative for CD19 and CD45 staining, indicating that syndecan expression is restricted to tumors having a well-differentiated phenotype. We conclude that syndecan acts as a matrix receptor on human myeloma cells but is not expressed by all tumors, suggesting that syndecan may participate in regulating myeloma cell adhesion to the bone marrow stromal matrix.
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PMID:Expression of syndecan regulates human myeloma plasma cell adhesion to type I collagen. 842 68

In mice and chickens, J chain appears to be expressed only in activated B cells and plasma cells. In humans, studies based mainly on transformed cells suggest that J chain expression may initiate during earlier stages in B lineage differentiation. In the present study, we isolated a series of hematopoietic subpopulations from human fetal and adult tissues by immunofluorescence cell sorting and examined each subpopulation for J chain expression by reverse transcriptase-PCR. In fetal and adult bone marrow, J chain transcripts were detected at all stages of B lineage differentiation, including the progenitor (CD34+/CD19-) and pro-B (CD34+/CD19+) cell subpopulations. J chain mRNA was also detected during fetal thymocyte development: double negative (CD4-/CD8-) through single positive (CD4+ or CD8+) cell subpopulations. The J chain message was not detected in peripheral CD3+ T cells, CD14+ monocytes, and CD56+ NK cells from either fetal or adult samples. The nucleotide sequence of J chain PCR products from CD34+/CD19- bone marrow progenitors and CD4+/CD8- thymocytes proved identical to the previously reported sequence of functionally spliced J chain mRNA. These results suggest that the J chain gene is transcriptionally active during early stages of both B cell and T cell differentiation, before the expression of their respective Ag receptors.
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PMID:The J chain gene is transcribed during B and T lymphopoiesis in humans. 866 93

Peripheral blood mononuclear cells (PBMC) from patients with multiple myeloma (MM) are here shown to include 23% +/- 2% of CD34+ cells, the majority of which coexpress CD19, as identified by a panel of 17 anti-CD34 antibodies. The expression of CD34 mRNA by sorted CD34+ PBMC from MM was confirmed by in situ reverse transcriptase-polymerase chain reaction (RT-PCR) with CD34-specific primers. The majority of CD34+ MM PBMC were CD19+ cells that expressed mRNA for CD19 and for rearranged IgH as identified with consensus IgH VDJ primers, as well as having cytoplasmic Ig, definitively identifying them as B cells, in absolute numbers of 0.06 to 0.69 x 10(9)/L of blood. CD34 is largely absent from normal B cells. To determine the clonal relationship of CD34+ B cells to autologous MM plasma cells, IgH VDJ DNA rearrangements of sorted CD34+ MM blood B cells were amplified by nested PCR using consensus primers followed by Southern blotting with allele-specific oligonucleotides for 7 MM patients, and clonotypic IgH mRNA expression was assessed for 4 MM patients using quantitative patient-specific in situ RT-PCR. For 9 of 11 myeloma patients tested, CD34+ blood B cells included IgH gene rearrangements or expressed IgH mRNA identical to that of autologous bone marrow plasma cells. For 4 of 4 MM patients, 74% to 94% of individual sorted CD34+19+ B cells expressed clonotypic IgH mRNA, as detected by in situ RT-PCR with patient-specific primers. Clonotypic IgH VDJ sequences were absent from B cells of unrelated MM patients and of normal donors. Clonotypic CD34+ B cells were detected before, during, and after treatment, and during relapse. Our results indicate a clonal relationship between CD34+ MM B cells and malignant plasma cells. We speculate that CD34 may play an important role in the biology of myeloma by facilitating extravasation from blood and thus spread of myeloma through the skeletal system.
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PMID:CD34+ cells in the blood of patients with multiple myeloma express CD19 and IgH mRNA and have patient-specific IgH VDJ gene rearrangements. 905 69

The presence of HCV RNA in peripheral blood mononuclear cells (PBMC) has been reported. To identify the cell populations carrying HCV RNA, the presence and amount of HCV RNA was investigated by limiting dilution nested reverse transcriptase-polymerase chain reaction (PCR) in PBMC subpopulations fractionated by automated cell sorting. Fifteen chronically HCV-infected patients were included in the study, 4 of whom also had mixed cryoglobulinemia. HCV RNA was present in the CD19 cells of all 15 patients, but only 5 (35.7%) of 14 and 5 (41.6%) of 12 showed HCV RNA in CD3 and CD14 cells, respectively (P < .001 by Fisher's test for each comparison). The median titer of HCV RNA was 1 PCR unit/380 CD19 cells, compared with median of 1 PCR unit/6600 PBMC as a whole. Titration was difficult in the CD3 and CD14 cells because of the frequent negativity of the first diluted sample. This study suggests that HCV RNA is selectively concentrated in B cells.
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PMID:Detection of hepatitis C virus RNA in CD19 peripheral blood mononuclear cells of chronically infected patients. 935 20

We have investigated a case of acute myelocytic leukaemia derived from myelodysplastic syndrome (MDS-AML) with an 8;21 translocation. In this case the AML1/MTG8 (ETO) fusion transcript was not detected by reverse transcriptase-polymerase chain reaction (RT-PCR), and the rearrangement of the AML1 gene locus was not detected by Southern blot nor pulse field gel electrophoresis (PFGE) analyses using specific probes for the AML1 gene. Fluorescence in-situ hybridization (FISH) study using cosmid probes for 21q22 revealed that the breakpoint of 21q22 was telomeric to the AML1 gene locus and centromeric from D21S259, 351, 3421 loci. This is the first report concerning the t(8;21)(q22;q22) carrying AMLs (de novo AML, MDS-AML and therapy-related AML) to show that the breakpoint at 21q22 is located outside the AML1 gene locus. It is also noteworthy that the cell-surface antigen expression pattern of the bone marrow (BM) blasts was changed from CD7+ CD2+ CD13+ CD33+ CD19- CD11b+ CD14+ CD36+ to CD7- CD2- CD13+ CD19+ CD11b- CD14- CD33+ CD34+ CD36- CD56+ during leukaemic progression, and the pattern in leukaemic phase was similar to the characteristic phenotype of de novo AML cases with t(8;21), when the AML1/MTG8 fusion transcripts are always detected by RT-PCR.
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PMID:Genetic analysis of 8;21 chromosomal translocation without AML1 gene involvement in MDS-AML. 940 Oct 77

Epstein-Barr-virus-associated posttransplant lymphoproliferative disease ranges from transient lymphadenitis to aggressive lymphoma. This study characterizes an in vitro model to study the pathogenesis of this disease with a cell culture system. Five B-cell lines derived from posttransplant lymphoproliferative disease tissue were characterized with regard to immunophenotype, karyotype, molecular genetics, cytokine production, and growth regulation. All cell lines expressed CD19, CD21, CD22, CD43, and CD77, but not CD10 antigens. Immunoglobulin light chain restriction was seen in four of five cell lines, and cytogenetic abnormalities were demonstrable in three of the five. Cells proliferating in culture contained multiple Epstein-Barr virus episomes and showed lytic viral replication. All cell lines produced tumor necrosis factor-beta and interleukin-10 without evidence of autocrine growth regulatory loops involving these cytokines. No evidence of IL-1 alpha, IL-2, IL-4, IL-5 or IL-6 production was found by reverse transcriptase polymerase chain reaction. Adding 500 U IFN-alpha/ml to the culture medium resulted in 30% inhibition of [3H]thymidine incorporation.
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PMID:In vitro culture of B-lymphocytes derived from Epstein-Barr-virus-associated posttransplant lymphoproliferative disease: cytokine production and effect of interferon-alpha. 946 86


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