Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Twelve long-term cell lines were established from peripheral blood mononuclear cells (PBMC) or cerebrospinal fluid cells of patients with human T lymphotropic virus type I (HTLV-1) seropositive tropical spastic paraparesis (TSP) originating from the French West Indies, French Guyana or the Central African Republic. Most of these long-term interleukin-2-dependent cell lines exhibited a pattern characteristic of CD4(+)-activated T cells with high expression of CD2, CD3 and CD4 antigens, associated with a strong density of TAC and DR molecules. Nevertheless, in five cases CD8 expression was present at a significant level. HTLV-I antigens were never detected in uncultured PBMC, but they were expressed in a few cells after short-term culture and after 4 months the majority of the cells were HTLV-I positive, as demonstrated by indirect immunofluorescence (IF) using polyclonal or monoclonal anti-p19 and anti-p24 antibodies. Low and variable levels of reverse transcriptase activity were detected in supernatant fluids of these cell lines only after 4 months of culture, when at least 50% of the cells exhibited HTLV-I antigens by IF. However, numerous type C HTLV-I-like viral particles were detected, mostly in the extracellular spaces, with rare budding particles. Similar findings were found in three T cell lines derived from West Indian and African patients with adult T-cell leukaemia/lymphoma (ATLL). Differences in high Mr polypeptides were detected by Western blot in cell lysates when comparing TSP- or ATLL-derived T cell lines. Thus a signal of 62K was easily detectable in all the TSP lines, but not in the ATLL lines. In all cell lines bands corresponding to p53, p24 and p19 viral core polypeptides were present, as was the env gene-coded protein p46.
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PMID:Cell surface phenotype and human T lymphotropic virus type 1 antigen expression in 12 T cell lines derived from peripheral blood and cerebrospinal fluid of West Indian, Guyanese and African patients with tropical spastic paraparesis. 230 64

Infection with a simian retrovirus (STLV-I) closely related to human T-lymphotropic virus type I (HTLV-I) was investigated in non-human primates living in their native countries in Africa and Asia. Serum antibodies cross-reacting with HTLV-I antigens were detected in 85 of 567 non-human primates of 30 species. Seropositive animals were found among African green monkeys, olive baboons, Sykes' monkeys, mandrills and patas monkeys in several countries in Africa, and cynomolgus monkeys, Celebes macaques and siamangs in Indonesia. The frequency of seropositivity was much higher in adult than in young African green monkeys, cynomolgus monkeys and Celebes macaques. STLV-Is were isolated by establishing II lines of virus-producing lymphoid cells in the presence of interleukin-2 from 5 species of seropositive non-human primates, i.e. the African green monkey, Sykes' monkey, Celebes macaque, cynomolgus monkey and siamang. All these cell lines had T-cell markers and Tac antigen, and the cell lines from the African green monkey and Sykes' monkeys were Leu2a+ while those from other species were Leu3a+. These cell lines expressed viral antigens reacting with human sera from adult T-cell leukemia (ATL) patients and monoclonal antibodies (MAbs) against p19 and p24 of HTLV-I core proteins, and produced virus particles having RNA-dependent DNA polymerase activity. Cellular DNAs from these cell lines contained provirus sequences homologous to HTLV-I, shown by Southern blot hybridization. The restriction patterns of these provirus genomes were different from those of HTLV-I and were also dissimilar in the different species.
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PMID:Serological survey and virus isolation of simian T-cell leukemia/T-lymphotropic virus type I (STLV-I) in non-human primates in their native countries. 244 Aug 20

The Fairfield Hospital experience with isolation of HIV from peripheral blood leucocytes, cerebrospinal fluid and semen is described. To date HIV has been isolated from single specimens of blood from 45% of patients with AIDS, 35% of patients with lymphadenopathy syndrome AIDS-related complex or ARC and 14% of asymptomatic antibody positive individuals. HIV was recovered from peripheral blood leucocytes in the presence of phytohemagglutinin and interleukin-2. The presence of virus in the supernatant fluid was detected using reverse transcriptase and immunofluorescence assays. Supernatants with borderline activity were confirmed by infection of a continuous cell line.
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PMID:Isolation of HIV from Australian patients with AIDS, AIDS related conditions and healthy antibody positive individuals. 245 95

Two strains of feline immunodeficiency virus (FIV) were isolated directly from peripheral blood mononuclear cells (PBMCs) of Japanese domestic cats or indirectly from PBMCs of specific pathogen free (SPF) cats inoculated with whole blood from naturally infected cats with FIV by cocultivation with primary PBMCs from SPF cats. Two isolates, designated as FIV TM 1 and FIV TM 2, had a lentivirus-like morphology by electron microscopy, a tropism for interleukin-2 dependent T-lymphocytes and Mg2+-dependent reverse transcriptase activity. By immunoblotting the isolates gave bands at 130, 48, 44, 40, 28, 17, and 13 kDa, and these bands except 130 kDa were detected in FIV Petaluma strain when reacted with the plasma of cats infected naturally with FIV TM 1 strain.
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PMID:Preliminary comparisons of the biological properties of two strains of feline immunodeficiency virus (FIV) isolated in Japan with FIV Petaluma strain isolated in the United States. 248 Jul 65

Bovine leukemia virus (BLV) infection of rabbits provides a safe and relatively inexpensive in vivo mammalian system for the study of the mechanisms controlling expression of a unique group of lymphotropic retroviruses. This group of viruses, which includes C-type human T-lymphotropic virus types I and II and lentiviruslike human immunodeficiency virus type 1, possesses genes coding for "trans-activating" products. Rabbits experimentally inoculated with BLV became persistently infected, as demonstrated by a number of tests. All BLV-inoculated rabbits developed persistent serum antibody to BLV. Furthermore, all BLV-inoculated rabbits had peripheral blood mononuclear cells which, when stimulated, expressed the virus, as demonstrated by viral induction of syncytium formation in a BLV-susceptible fibroblast line. The presence of BLV in circulating cells was confirmed by using peripheral blood mononuclear cells from randomly selected BLV-inoculated rabbits, which showed the presence of viral reverse transcriptase activity, BLV transcriptional activity, or BLV proviral DNA. Additional tests showed that infected lymphocytes maintained in culture with recombinant human interleukin-2 formed multinucleated giant cells and produced virus when incubated in cytokine-containing medium. BLV-infected rabbits also showed alterations in several parameters associated with immunity, beginning 6 months after inoculation. Thirty-eight percent of infected rabbits developed abnormally low T-cell responses, as measured by phytolectin stimulation, and T-cell responses cycled between normal and abnormally low over a period of 20 to 24 months. Forty-four percent of rabbits infected for longer than 12 months suffered from recurrent conjunctivitis and rhinitis. By 24 months postinoculation, 28% of infected rabbits were dead or were killed because of poor clinical condition.
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PMID:Persistent infection of rabbits with bovine leukemia virus associated with development of immune dysfunction. 255 35

Simian retroviruses closely related to human T-cell leukemia virus (HTLV) were isolated by establishing virus-producing lymphoid cell lines from 7 species of non-human primates. By co-cultivation with human umbilical cord-blood cells and/or in the presence of interleukin-2, lymphoid cell lines were successfully established from the chimpanzee. African green monkey, pig-tailed macaque, red-faced macaque, Formosan monkey, Japanese monkey and bonnet monkey that had antibodies against HTLV antigens. These cell lines reacted with human sera of ATL patients and monoclonal antibodies against p19 and p24 of HTLV antigens. Cellular DNAs contained the provirus sequences homologous to HTLV-I by Southern blot hybridization. Moreover, they produced extracellular type-C virus particles and RNA-dependent DNA polymerase. All of these lymphoid line cells had Tac antigen, interleukin-2 receptor, and those of chimpanzee and red-faced macaque had helper/induced T-cell markers, while those derived from African green monkey had suppressor/cytotoxic T-cell markers. Furthermore, simian HTLV-related viruses of pig-tailed macaque, red-faced macaque and Japanese monkey were transmitted to human lymphocytes on co-cultivation.
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PMID:Isolation of simian retroviruses closely related to human T-cell leukemia virus by establishment of lymphoid cell lines from various non-human primates. 257 38

Infection of normal peripheral blood T cells by the acquired immune deficiency syndrome (AIDS)-associated retrovirus (ARV) was evaluated in long-term cultures of helper-inducer T cells (T4 cells). Cells that were inoculated with ARV and maintained in medium supplemented with interleukin-2 remained productively infected with this virus for more than 4 months in culture, although they showed no cytopathic effects characteristic of acute ARV infection. The presence of replicating virus was demonstrated by reverse transcriptase activity of culture fluids and by viral antigens and budding particles detected on cells by immunofluorescence and electron microscopy. Virus produced in these cultures remained infectious and could induce cytopathic effects and viral antigens in uninfected lymphoid cells. The finding that normal lymphocytes may be productively infected by an AIDS retrovirus in the absence of cell death suggests that a range of biologic effects may occur after infection in vivo.
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PMID:Persistent noncytopathic infection of normal human T lymphocytes with AIDS-associated retrovirus. 299 22

Human retroviruses have been detected in supernatants of cultures of Ficoll-enriched lymphocytes from peripheral blood, lymph nodes and bone marrow of (a) 32 out of 42 patients with Acquired Immunodeficiency Syndrome (AIDS), (b) 34 out of 64 patients with AIDS-related Complex (ARC), (c) 9 out of 18 asymptomatic children born from Human Immunodeficiency Virus (HIV) seropositive mothers, and (d) 9 out of 28 asymptomatic drug abusers or hemophiliacs. Virus detection was monitored by assaying culture supernatants for the presence of Mg++-dependent reverse transcriptase (R.T.) activity. A number of these virus-positive sups were passaged repeatedly in cultures of phytohemagglutinin-stimulated and Interleukin-2 (IL-2) treated fresh lymphocytes from healthy blood donors. Occasionally, multiple samples were obtained at varying time intervals from the same patient and consistently yielded detectable retroviral activity. Several isolates were characterized as closely related if not identical to HIV, HTLV-IIIB strain, since cells from either patients' own lymphocyte cultures or subcultures infected with passaged virus were stained in an indirect immunofluorescent assay with both patients sera and monoclonal antibody against p24 antigen of the HTLV-IIIB strain. Representative isolates, grown on fresh lymphocytes of healthy donors and metabolically labelled with 35S-cysteine, were also analyzed in a radioimmunoprecipitation assay (RIPA) against patients' sera to define their antigenic pattern, which was widely superimposable to that obtained with HTLV-IIIB-infected H9 cells. DNA from lymphocytes infected with 2 representative isolates were Southern-blotted and probed with an insert from a plasmid containing the entire genome of the HTLV-IIIB strain. The hybridization patterns were comparable with those obtained with DNA from H9-infected cells.
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PMID:Recovery of HIV-related retroviruses from Italian patients with AIDS or AIDS-related complex and from asymptomatic at-risk individuals. 343 18

We report the successful generation of human T-cell hybridomas that constitutively secrete lymphokines. An acute lymphoblastic leukemia T-cell line, CCRF-H-SB2, free of reverse transcriptase and mycoplasma, was sensitized to hypoxanthine, aminopterin, and thymidine (HAT) by selecting out a mutant deficient in hypoxanthine guanine phosphoribosyl transferase (HGPRT) in 8-azaguanine. Peripheral blood T lymphocytes from normal donors were incubated in vitro with 10 micrograms/ml of concanavalin A for 48 h and subsequently fused with the CCRF-H-SB2 HAT-sensitive cell line. Following 5 weeks in culture, 38 of 440 wells (8.6%) demonstrated hybridoma growth. Supernatants of these cultures were screened for interleukin-2 (IL-2), chemotactic factor, interferon, migration inhibition factor, and macrophage-activating factor activities. Twelve (of 38) hybrids exhibited IL-2 activity, and eight of these were successfully cloned. The highest secreting clone was demonstrated to have mRNA to IL-2 while the parent CCRF-H-SB2 had no detectable mRNA to IL-2. Three hybrid cultures produced chemotactic factor; one was successfully cloned and grown in serum-free medium, where it continued to constitutively produce chemotactic factor as well as IL-2 activity. The chemotactic factor was determined to have the same molecular weight (12,500 daltons) as leukocyte-derived chemotactic factor. Constitutive IL-2 production remained stable for over 12 months. None of the hybridomas tested produced detectable levels of gamma interferon, migration inhibition factor, or macrophage activation factor. Because these T-cell hybridomas produce lymphokines constitutively and this phenotype is stable, they can be an important source of highly purified human lymphokines for clinical and laboratory investigations.
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PMID:The generation of stable human T-cell hybridomas which constitutively produce interleukin-2 and chemotactic factor. 393 Mar 88

Peripheral blood lymphocytes from male individuals at risk for AIDS were cultured in the presence of interleukin-2. Approximately 90% of cultures originating from pre-AIDS and AIDS patients were retrovirus-positive as detected by the reverse transcriptase (RT) assay and confirmed by electron microscopy. Prolonged incubation of the retrovirus-positive cells resulted in the establishment of several interleukin-2-independent B-lymphoblastoid cell lines. These cells were positive for Epstein-Barr virus (EBV)-specific antigens and contained EBV particles. When irradiated cells from the new lines were cocultivated with an RT-negative T-cell line CEM, an efficient transmission of retrovirus was detected. The supernatants from cocultivated cells had 5-10 fold higher levels of RT activity as compared with the supernatant from the cell line alone. Type-C retroviral particles and budding structures similar to those of human T cell leukemia virus type III (HTLV-III) and lymphadenopathy-associated virus (LAV) were found by electron microscopy. HTLV-III/LAV-specific polypeptides were detected by immunoprecipitation with sera from lymphadenopathy and AIDS patients, but not with sera from healthy individuals. Our data suggest that EBV-infected B lymphocytes from individuals at risk for AIDS may serve as a biological reservoir for the AIDS-associated retrovirus.
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PMID:Establishment of retrovirus-, Epstein-Barr virus-positive B-lymphoblastoid cell lines derived from individuals at risk for acquired immune deficiency syndrome (AIDS). 608 40


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