1,721,180 research outputs found
The biological basis for clinical use of interferon.
No full textInterferons represent the body's most rapid defence against virus infection. Natural recovery from viral infections is correlated with interferon production; the inhibition of interferon enhances the severity of infection and interferon has been shown to protect animals from some viral infections. beta-Interferon is produced by fibroblasts in response to viral infection. Leucocyte (a) interferon may be induced by foreign or infected cells or by viruses, and it is continuously released into the bloodstream during infection, declining with time. gamma-Interferon are produced later in viral infection by virus-sensitized T lymphocytes. The antiviral action of interferon is induced by interaction with specific receptors on cell surfaces leading to translation of antiviral proteins. Interferons may also enhance immune responses by increasing expression of lymphocyte surface antigens and by increasing the cytotoxic activity of natural killer cells. In chronic hepatitis B and C, it seems likely that interferon's antiviral activity is responsible for the early fall of viral products, while its immunomodulatory activity is responsible for long-term effects, including the destruction of infected hepatocytes, with persistent loss of viral antigens and seroconversio
Human interferon-gamma enhances the expression of class I and class II major histocompatibility complex products in neoplastic cells more effectively than interferon-alpha and interferon-beta
No full textReplication of human immunodeficiency virus: yield of infectious virus under single growth cycle conditions.
No full textReplication kinetics of HIV was studied under single growth cycle conditions by backtitrating infectious virus released or remained cell-associated at each time point. Under these conditions HIV seems to replicate faster than previously estimated. The amount of cell-associated virus always exceeds the one detectable in the medium
Interactions of interferon with in vitro model systems involved in hematopoietic cell differentiation.
No full textDifferences in the expression and release of DR, BR, and DQ molecules in human cells treated with recombinant interferon gamma: comparison to other interferons
No full textThis study presents a comparative analysis of the effects of different interferons tlFNJ on the three recognizable subsets of human HLA class II molecules: DR, BR, and DQ. Both cellular expression and shedding of class II molecules have been determined on three different cell type.*. The results can be summarized as follows: class II molecules are marked!~ increased by IFN gamma: IFN beta has a lower enhancing effect, and IFN alpha has only a slight, if any, effect. Kinetically, the action of IFN gamma is prompter and longer lasting than that of IFN beta. DQ expression is much more enhanced by IFN gamma than either DR or BR: IFN beta has the same effect on all three subsets. Parallel changes of the cellular expression and of the shedding of these molecules are observed. A melanoma and a lymphob/astoid cell line and perzpheral blood mononuclear cells show qualitatively similar modificatio
Interferon effects on Friend leukaemia cells. I. EXpression of virus and erythroid markers in untreated and dimethyl sulphoxide-treated cells
No full textCD4-positive lymphoid cells rescue HIV-1 replication from abortively infected human primary endothelial cells.
No full textHuman primary endothelial cell cultures, derived from umbilical vein (HUVEC), can be infected by different strains of HIV-1, but mature virus production remains undetectable both in supernatants and in cellular extracts. Yet viral DNA-is transiently detectable during the first days of infection, but progressively declines during the subsequent days. This finding is characteristic of abortive infections. Co-culture of HUVEC carrying HIV DNA with activated peripheral blood mononuclear cells or with CD 4-positive lymphoid cells elicited a massive cpe (syncytia formation and cell degeneration) in the latter cells, caused by the establishment of productive HIV-1 infection. HUVEC infected in the presence of AZT were significantly impaired in the ability to transmit the infection of CD 4-positive cells, indicating that active DNA synthesis is required in HUVEC before rescue by CD 4-positive cells.
These results are of interest in view of the possibility that endothelial cells can play a role in the transmission of HIV-1 infection from infected pregnant women to the foetuses, and, more generally, suggest a potential role of endothelial cells as a transient reservoir of HIV-1
Interactions of interferon with in vitro model systems involved in hematopoietic cell differentiation.
No full textDifferential effects of gamma interferon on expression of HLA class II molecules controlled by the DR and DC loci.
No full textInterferon-gamma affected the expression of the products of the immunoassociated antigen complex by a differential modulation of DR- and DC-locus-controlled molecules. In melanoma M14 cells treated with interferon-gamma, levels of DR molecules were increased two- to threefold, whereas levels of DC molecules were increased six- to sevenfold. Similar effects were induced on the two allelic products of each locus
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