Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A total of 9 calves were used to test the interferon-inducing activity of strain Vulchedrum of the bovid Herpes virus 1. The virus of stomatitis vesiculosa adapted to cell cultures of calf kidney was used as an indicator of interferon. The antiviral action of interferon was demonstrated in the serum and the nose discharge of calves. The dynamics of interferon production in calves varied, depending on the venous, muscular, and tracheal route of application of the virus. Highest interferon titer in the serum was established at the venous application. In the nose discharge highest titers were found following tracheal application. Additional criteria demonstrating the presence of interferon in the positive serum and discharge samples were the unchanged activity at pH 2 and 4 degrees C for 24 hours; the unchanged activity following heating at 56 degrees C for 30 min; the unchanged activity following treatment with ether; the lack of activity following heating at 25 degrees C for 30 min; and the lack of activity at incubation with trypsin. The positive samples showed also antiviral unspecificity--inhibited was not only the virus of stomatitis vesiculosa, but also M. parainfluenza-3.
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PMID:[Interferon induction in calves after experimental infection with bovine herpesvirus 1]. 618 69

The production of interferon by bovine peripheral blood leukocytes infected with bovid herpesvirus 2 (BHV-2) was investigated in preparation for studying mechanisms of resistance to BHV-2. It was found that bovine peripheral blood monocytes produced high levels of interferon in response to BHV-2 inoculated at a multiplicity of 1. Virus-induced interferon was not stable at pH 2, was destroyed at 56 degrees C or by incubation with trypsin and was active against both vesicular stomatitis virus and BHV-2. Interferon of high specific activity was produced by incubating monocytes for 5 h with BHV-2 in serum-containing medium, replacing the inoculum with serum-free medium for an additional 16 h, and concentrating the serum-free medium by dialysis against dry polyethylene glycol. Interferon concentrations of 40,000 units per mg of protein were readily attained.
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PMID:Production of interferon by bovine peripheral blood monocytes infected with bovid herpesvirus 2. 618 82

Several Togaviridae of the alphavirus and flavivirus genera agglutinate trypsinized human group O erythrocytes (THOE) (Shortridge and Hu, 1976). Haemagglutinin titers of Semliki Forest virus (SFV) and Japanese encephalitis virus (JEV) measured with THOE were equivalent to, if not higher than, those obtained with Embden gander erythrocytes, even with unextracted haemagglutinin. Results obtained with THOE in JEV haemagglutination-inhibition tests on sera taken from a previously infected individual over a 20-yr period were similar to those measured during the initial JEV infection. The inhibition of SFV haemagglutinin production as measured with THOE was a very sensitive bioassay for chicken interferon: interferon titers were 6- to 10-fold higher than those obtained with the vesicular stomatitis virus plaque-reduction method. The generally greater availability of human erythrocytes (including those stabilized with glutaraldehyde), the simplicity of the trypsin treatment, and the possibility of using unextracted haemagglutinin recommend this technique for use with haemagglutinating Togaviridae.
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PMID:Interferon and antibody titrations using haemagglutinating Togaviridae and trypsinized human erythrocytes. 618 50

Interferon(IFN) can be produced from lymphocytes in vitro as well as in vivo using various immune stimuli. This paper shows that the amount of IFN or IFN-like substance increases in pregnancy sera as pregnancy proceeds. 1) IFN activity was detected in 45% of 97 pregnant women overall and more frequently as pregnancy went on. 2) The IFN was trypsin sensitive, beat labile, acid sensitive and species specific. 3) Maternal lymphocytes produced approximately twice as much interferon as cord blood lymphocytes did by phytohemagglutinin stimulation. 4) IFN was detected in half of the mixed lymphocyte cultures(MLR) containing cord blood and maternal blood. Whether or not they can produce IFN may be an indication of the immunological competence of pregnant women and the interferon may contribute to the immunoregulation of fetal acceptance.
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PMID:[Interferon-like substance in pregnancy sera]. 619 Sep 68

Murine fibroblast interferon (MuIFN, 90% beta, 10% alpha) was associated with both positively and negatively charged liposomes formed by reverse-phase evaporation. This interferon-liposome association occurred predominantly in a manner that resulted in protection of a significant portion of the IFN's antiviral activity from trypsin digestion, yet also permitted biological expression of this activity without prior liposome disruption. A differential dissociation of antiviral and antimitogenic activities was observed with MuIFN associated with positively vs negatively charged liposomes, as reflected by differential sensitivities to trypsin inactivation. This may reflect either (1) differential associations of various molecular species of MuIFN with liposomes, or (2) that different portions of the IFN molecule are responsible for the antiviral and the antimitogenic activities.
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PMID:Partial dissociation of antiviral and antimitogenic activities of murine interferon after its incorporation into liposomes. 619 85

Cell-free cytoplasmic extracts of the Syrian hamster cell lines C13/SV28 and BHK-21F were immunogenic in Syrian hamsters. The resulting antisera cross-reacted completely with antisera against lymphocytic choriomeningitis virus (LCMV) in an immunoradiometric assay employing BHK-21F antigen. Several other Syrian hamster cell lines not previously known to be infected with LCMV were also strongly positive when assayed for viral antigens. Also, several mouse sera and antisera raised in Syrian hamsters against cells transformed by papovaviruses had high titers of anti-LCMV activity. No cytopathic effect was evident in any of the persistently infected cell lines. Culture media from these cells were not infectious and showed no evidence of defective interfering particles. However, cell-free extracts of all the persistently infected cells contained material capable of transmitting the persistent infection to uninfected cells of Syrian hamsters, rats, mice, green monkeys, and humans. The onset of infection is much slower than when LCMV virions are used. When 2 X 10(6) uninfected BHK cells were treated with an extract from 100 persistently infected cells, the new infection was apparent within about 12 days. When an extract from 10(6) cells was used, the new infection was apparent within about 5 days, but not sooner. The intracellular infectious material was sensitive to treatment with deoxycholate, Nonidet P-40, or ether but resistant to treatment with RNase or trypsin. It was also large (5,000S) and heterodisperse on sucrose gradients. The infectious material was probably contained in large lipid vesicles and their integrity was probably essential for infection. When a few persistently infected cells were cocultivated with many uninfected cells, a few discrete colonies positive for LCMV antigens were observed after about 5 days. Since the culture media were not infectious, the infection probably spread by cell-cell contact. Several different experiments indicated that interferon did not play a major role in mediating persistence in this case. Persistent infections by LCMV can be maintained without expression of extracellular virus particles and without appearance of large amounts of viral antigens on the cell surface. Cell-cell contact could still allow transmission of intracellular infectious material. In an animal, these properties could circumvent immune surveillance.
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PMID:Persistent infection of some standard cell lines by lymphocytic choriomeningitis virus: transmission of infection by an intracellular agent. 619 87

In the present work we show that sarcoma and normal hamster tissues contain a protein which agglutinates normal and transformed cells. The inhibition of agglutination by galacturonic acid and occasionally by fucose suggests a resemblance of this protein with vegetal lectins. When added 5 h after interferon, the crude semipurified and electrophoretically homogeneous preparations reduce within 20 h the antiviral state pre-established by interferon. These two biological tests have enabled us to monitor the subsequent purification steps. The isolation of the biologically active protein is greatly facilitated by its resistance to pepsin and nucleases, whereas its sensitivity to trypsin and Pronase suggests its proteinaceous character. Furthermore, the molecule is stable when heated 1-2 min at 100 degrees C in the presence or absence of sodium dodecyl sulfate. After pepsin treatment, Sephacryl G-200 gel filtration, and ion exchange chromatography on DEAE-cellulose, 25-40-fold purification can be obtained. When controlled by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, a double band (DEAE-cellulose sample) or single band (octyl-agarose sample) is detected in the 65,000-dalton region and no other contaminator is present. The eluted protein retains full biological activity when assayed by the degradation of the interferon-induced antiviral protection in the cell or titrated by cell agglutination.
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PMID:Sarcolectin: an interferon antagonist extracted from hamster sarcomas and normal muscles. Isolation, characterization, and purification. 619 52

The binding of [3H]leucine-labelled pure human interferon alpha from Namalwa cells to human FL and Daudi cells was studied, and evidence obtained to indicate receptor-mediated internalization of interferon. Cell surface-bound and internalized interferons were quantified separately as trypsin-released and unreleased radioactivities, respectively. At 37 degrees C, surface-bound interferon reached a maximum after 1 h and then decreased, while internalized interferon reached a maximum after 2 h. At 21 degrees C, in contrast, surface-bound interferon reached a maximum after 2 h and did not decrease thereafter; no internalization was observed. The same was true at 37 degrees C in the presence of NaF, indicating dependence of internalization on temperature and energy. In control cultures at 37 degrees C, internalized interferon, after reaching a maximum, decreased after prolonged incubation, and concomitantly acid-soluble radioactivity appeared in the culture medium. The decrease in internalized interferon and the emergence of degraded interferon were inhibited by the lysosomotropic agents, ammonium chloride and chloroquine. The fate of labelled interferon, bound to the cell surface of FL cells at 21 degrees C was studied at 37 degrees C, and the results indicated that trypsin-unreleased interferon was derived from the surface-bound interferon, and was secreted in part into the culture fluid in a degraded form upon prolonged incubation. The relation of internalization of interferon to its biological activity was studied in three ways. In FL cells, the antiviral activity was not induced when internalization of interferon was entirely blocked (at 21 degrees C or in the presence of NaF at 37 degrees C). In Daudi cells, both 2'-5'-oligoadenylate (2-5A) synthetase induction by interferon and internalization of interferon were inhibited completely by diethyldithiocarbamate (DDC), whereas in the case of FL cells, DDC inhibited neither 2-5A synthetase induction nor internalization of interferon. Raji cells, which have an interferon-specific binding site on the cell surface but are insensitive to interferon, were found not to internalize interferon, whereas other Burkitt's lymphoma cells, Daudi and Namalwa, which are sensitive to interferon, did internalize it. These findings suggest (but do not prove) that internalization is required for the establishment of interferon activity.
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PMID:Cell surface receptor-mediated internalization of interferon: its relation to the antiviral activity of interferon. 619 40

Interferon production was demonstrated by the goldfish-derived CAR cell line in response to infection by goldfish virus-2. Supernatants of infected cultures provided antiviral protection to CAR cells and another cell line derived from goldfish, ABIII. The protective factor retained activity after ultracentrifugation, dialysis, freezing and thawing, acid treatment (pH 2), or heating to 56 degrees C but was sensitive to trypsin. Supernatants of infected cultures did not affect adsorption of virus. Previous studies have shown that replication of goldfish virus type 2 is enhanced by pretreatment of cultures with subcytotoxic concentrations of carbaryl. In the present study, pesticide-treated cultures were found to synthesize reduced levels of interferon.
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PMID:Suppression of interferon synthesis by the pesticide carbaryl as a mechanism for enhancement of goldfish virus-2 replication. 620 Nov 37

A homogeneous population of trypsin-resistant epidermal cells has been isolated from newborn ICR mice. These cells are characterized by adherence, receptors for Fc-IgG, ATPase activity, phagocytosis of latex particles and opsonized sheep erythrocytes, and secretion of lysozyme and interferon. The production of interferon by these cells suggests that they may be important in protection against viral infections of the skin as well as in regulation of immune responses. The ultrastructure of these trypsin-resistant epidermal cells shows striking similarity to that of reticuloendothelial cells.
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PMID:Isolation and characterization of interferon-producing reticuloendothelial cells from mouse epidermis. 620 12


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