1,720,976 research outputs found
DENSITY-DEPENDENT RESPONSIVENESS TO AUTOCRINE GROWTH-FACTORS OF EPSTEIN-BARR-VIRUS TRANSFORMED HUMAN LYMPHOCYTES-B
No full textAnalysis of the growth requirements of Epstein-Barr virus (EBV)-transformed B lymphocytes shows that interleukin 1 and thioredoxin, a disulfide reducing enzyme, are able to induce a marked increase in DNA synthesis in the early phases of in vitro culture. By contrast, interleukin 6 induces a steady increase in DNA synthesis comparable to that observed with crude conditioned supernatant. Furthermore, EBV-transformed B cells exhibit a density-dependent responsiveness to autocrine growth factors, thus suggesting that growth regulation of EBV-transformed B cells might result from the interplay between different self-stimulating soluble factors and from the competence of the cells to respond to autocrine growth factors
DETECTION OF AN IDIOTOPE ON A HUMAN MONOCLONAL AUTOANTIBODY BY MONOCLONAL ANTIIDIOTYPIC ANTIBODY AND ITS RELATIONSHIP TO EPSTEIN-BARR VIRUS-INDUCED AUTOIMMUNITY
No full textWe have recently described a human IgM monoclonal antibody (mAb), reactive with both self antigens, i.e., cytoskeleton filaments and smooth muscle, and Epstein-Barr virus (EBV)-induced nuclear antigen (EBNA), produced by EBV-transformed B lymphocytes isolated from a patient with infectious mononucleosis (IM). In order to achieve higher antibody secretion in culture supernatant, the mAb-producer cells were fused with ouabain-resistant mouse myeloma cells and a stable human-mouse heterohybrid, coded HY 5488, producing up to 80 micrograms/ml IgM mAb, was isolated after 4 cloning procedures. Purified HY 5844 mAb was used to immunize mice for the production of a murine anti-idiotypic mAb, which was used to probe the expression of the idiotope of HY 5488 mAb (Id 5488) in sera of IM patients and normal controls by ELISA. It was found that Id 5488 is expressed both in IM patients and normal controls, and that Id 5488 expression is significantly higher in IM patients' sera; furthermore, in IM sera a statistically significant correlation between Id 5488 expression and anti-cytoskeleton and anti-smooth muscle autoantibodies was found. It is suggested that at least part of EBV-induced IgM autoantibodies appearing during IM are secreted by B lymphocytes programmed to the production of "natural antibodies" bearing Id 5488-like idiotopes
Potential role of the Epstein-Barr virus in systemic lupus erythematosus autoimmunity
No full textOBJECTIVE: To investigate the possibility that Epstein-Barr virus (EBV), the agent of infectious mononucleosis (IM), may play a role in systemic lupus erythematosus (SLE).
METHODS: EBV was searched for by PCR and by culture isolation in oropharyngeal lavage fluids of 15 SLE patients and, as controls, in 13 IM patients and in 28 healthy individuals with past EBV infection. Computer analysis was performed to select an antigenic domain of the virus-encoded nuclear antigen EBNA-2, in order to set up a synthetic peptide-based immunoassay. IgG antibodies to a 20-amino acid synthetic peptide derived from the selected domain of EBNA-2 (354GRGKGKSRDKQRKPGGPWRP373) were titrated in the sera of 20 SLE patients, 24 IM patients and 12 healthy subjects.
RESULTS: EBV type 1 DNA was demonstrated by PCR in the oropharyngeal secretions of 8 SLE patients and the virus was isolated from 6 DNA-positive specimens. Moreover, 50% of the patients with SLE and 100% of the patients in the acute phase of IM, but none of the EBV-seropositive normal individuals, produced IgG antibodies to the EBNA-2-derived synthetic peptide. Computer analysis revealed a high degree of homology between the EBNA-2 354GRGKGKSRDKQRKPGGPWRP373 sub-sequence and the antigenic C-terminal domain 101GRGRGRGRGRGRGRGGPRR119 of the SmD1 ribonucleoprotein, a target of autoantibodies in a portion of SLE patients.
CONCLUSION: We suggest the possibility that EBV may establish a persistent infection at least in a certain number of SLE patients. The antibodies elicited by the viral antigen EBNA-2 may cross-react with SmD1, thus indicating a role of EBV-specific immune responses in the outcome of SmD1 autoantibodies in SLE patients
EPSTEIN-BARR VIRUS-TRANSFORMED LYMPHOCYTE-B PRODUCE LOW-MOLECULAR MASS MOLECULES WITH AUTOCRINE GROWTH-FACTOR AND COMPETENCE FACTOR ACTIVITY
No full textA human Epstein-Barr virus (EBV)-positive lymphoblastoid B cell line, named BA-D10-4, produces a factor of a molecular mass less than 10 kDa that promotes cell proliferation of both BA-D10-4 cells and other human T or B lymphoid cell lines, either EBV-positive or -negative. The factor synergizes with higher molecular mass autocrine growth factors and makes both BA-D10-4 cells and B cell lines from Burkitt's lymphoma, but not cells from T cell leukemia, more responsive to interleukin-1 and interleukin-6. Therefore, this low molecular mass factor seems to be an autocrine growth factor per se and to have the characteristics of a competence factor
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
ANTIBODIES TO HISTONES IN INFECTIOUS-MONONUCLEOSIS
No full textA polyspecific human monoclonal (auto)antibody, isolated from a patient in the acute phase of infectious mononucleosis, was found to react with all subfractions (H1, H2A, H2B, H3 and H4) of histones. This finding prompted us to study the occurrence of antibodies to histones in sera of patients with infectious mononucleosis. It was found that IgM binding to histones was detectable both in control and patient sera; however, sera from patients showed binding values of IgM antibodies to histones significantly higher than those of healthy controls; moreover, both in control and patient groups anti-histone IgM activity was found to correlate with serum IgM concentration. These findings suggest that anti-histone IgM antibodies belong to the class of antibodies defined as "natural antibodies" and that their increase during infectious mononucleosis is due to Epstein-Barr virus-induced polyclonal B cell activation
PCR ELISA for the quantitative detection of Epstein-Barr virus genome
No full textA highly sensitive and nonradioactive microplate hybridization assay for the detection of Epstein–Barr virus
(EBV)-specific polymerase chain reaction (PCR) product was developed. The PCR product is labelled by adding
digoxigenin-dUTP directly to the reaction mixture and, after denaturation, is captured by a microtitre plate coated
with an extravidin-linked biotinylated probe. Captured products are reacted with a peroxidase-conjugated anti-digoxigenin
antibody and detected using tetramethylbenzidine. The assay detected less than ten EBV genomes in a
background EBV-negative DNA of 0.75 mg and, when tested on clinical samples, it was able to define the viral load
in throat washings of patients with acute infectious mononucleosis, immunosuppressed patients with HIV infection,
and rare normal individuals who shed the virus in the oropharynx
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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