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:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Culture supernatants of splenic T cells from susceptible CBA mice chronically infected with Trypanosoma cruzi contain a suppressive substance which can inhibit the induction of delayed-type hypersensitivity (DTH) to a wide range of antigens. The suppressive substance is distinct from T. cruzi antigen inasmuch as the supernatant depleted of any residual T. cruzi antigen by an affinity column still retains the suppressive activity, whereas addition of T. cruzi antigens to control supernatant did not confer suppressive function. The suppressive supernatant does not contain detectable levels of IL-1, IL-2, IL-3, or IFN-gamma but a modest level of IL-1 and IL-2 inhibitory activities. However, both these inhibitory activities elute at a different position from the DTH suppressive activity on gel filtration. The DTH suppressive activity is heat labile (1 h, 56 degrees C), cryostable, but destroyed by trypsin treatment. It binds to ricin but not to lentil lectin. Sepharose 4B gel filtration and HPLC analysis in mild chaotropic agents (urea, ethylene glycol) demonstrate that the suppressive substance has an apparent Mr of 30 to 60 kDa, but full DTH-suppressive activity is retained only in an aggregated form.
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PMID:Suppressive substance produced by T cells from mice chronically infected with Trypanosoma cruzi. II. Partial biochemical characterization. 312 53

This study was performed to determine the effect of Pseudomonas aeruginosa on gamma interferon (IFN-gamma) production by antigen-stimulated human T-cell clones. Crude bacterial filtrates prepared from certain strains of P. aeruginosa inhibited IFN-gamma production by T cells and reduced the antiviral activity of preformed IFN-gamma. Bacterial filtrates prepared from mutant strains that did not produce the exoenzyme alkaline protease (AP) did not inhibit IFN-gamma activity. The inhibitory activity of bacterial filtrates was heat and trypsin sensitive and was neutralized by an antiserum to AP. Crystalline AP mimicked the effects of the bacterial filtrates, and an inactive filtrate from a protease-deficient mutant strain was reconstituted by the addition of AP. AP-treated recombinant IFN-gamma showed altered migration on Western blots (immunoblots) of polyacrylamide gels, and this modification correlated with a dose-dependent loss of antiviral activity. The ability of recombinant IFN-gamma to elevate the expression of Fc receptors on cells of the U-937 histiocytic cell line was also diminished by AP treatment. These results indicate that the Pseudomonas protease AP can inhibit the antiviral and immunomodulatory activities of IFN-gamma.
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PMID:Pseudomonas aeruginosa alkaline protease degrades human gamma interferon and inhibits its bioactivity. 313 65

Supernatants from PHA-activated human peripheral blood mononuclear cells, depleted of virtually all IL-2 activity by an anti-rIL-2 immunoadsorbent column, contain a factor(s) which synergizes with rIL-2 in facilitating the generation of allogeneic human CTL responses in vitro. This factor, provisionally termed CTL maturation factor (TcMF), did not appear to promote CTL responses in the absence of rIL-2. Furthermore, it acted later than IL-2 in facilitating CTL responses and could not be replaced by recombinant IFN-gamma. In this report we show that rIFN-alpha, rIL-1 alpha, and rIL-1 beta likewise lack TcMF activity. The TcMF activity in lymphokine-containing culture supernatants could be eliminated by trypsin or pronase but not by neuraminidase or RNase. Gel filtration revealed two peaks of TcMF activity, one at 12,000 to 25,000 Da and the other at 45,000 to 65,000 Da. Isoelectrofocusing demonstrated substantial charge heterogeneity. The majority of TcMF activity was recovered between pI 4.0 and pI 5.5 with a minor component at pI 6.5, corresponding to the areas in which IL-1 activity was also found. However, TcMF activity could be separated from IL-1 by reverse-phase HPLC. Moreover, TcMF recovered following reverse-phase HPLC was also found to be depleted of IL-4 activity. These studies suggest that TcMF activity is mediated by a protein(s) distinct from IL-1, IL-2, IL-4, and interferon-alpha or-gamma.
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PMID:Characterization of a factor(s) which synergizes with recombinant interleukin 2 in promoting allogeneic human cytolytic T-lymphocyte responses in vitro. 327 3

A lymphokine inhibitory for cellular DNA synthesis (termed STIF) was isolated from the culture supernatants of concanavalin A (Con A)-stimulated SD rat spleen cells. STIF inhibited the DNA synthesis of mouse bone marrow cells as well as mouse leukemia cells. STIF has an apparent m.w. of 45,000 to 50,000 and is separable from IL 2, m.w. 20,000 to 25,000, by Sephacryl S-200 gel filtration, but not from immune interferon (IFN) having the same m.w. as STIF. Con A-Sepharose chromatography of the fraction containing STIF and IFN could separate these lymphokines into Con A-unbound and Con A-bound fractions, respectively. Further fractionation of the STIF fraction by DEAE-Sephadex A-50 or Mono Q-FPLC anion exchange chromatography indicated that the STIF fraction contained two components of STIF activity, both showing the same pI value (5.1 to 5.6) on flat-bed isoelectric focusing. STIF was characterized as a sugar-free lymphokine of trypsin-sensitive protein nature.
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PMID:Stimulated rat T cell-derived inhibitory factor for cellular DNA synthesis (STIF). I. Isolation and characterization. 391 68

Serum specimens from mice treated orally with Ge-132 (100 mg/kg) exhibited antitumor activity against Ehrlich (allogeneic) and RL 1 (syngeneic) ascites tumors in BALB/c mice. Sera obtained from mice 24 hours after Ge-132 administration displayed the highest antitumor effect and the antitumor activity was dose-dependent. Sera prepared from mice 12, 36 or 48 hours after Ge-132 treatment had no protective effect. Circulating interferon (IFN) was induced at 24 hours after administration. The antiviral activity of serum from Ge-132-treated mice was inactivated by treatment with trypsin, low pH, and anti-IFN-gamma antiserum. The inactivated preparations of serum IFN induced by Ge-132 did not show antitumor activity when administered to mice bearing Ehrlich ascites tumors. These results suggest that the antitumor activity in the sera of Ge-132-treated mice may have been expressed through IFN-gamma which was induced by Ge-132.
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PMID:[Ability of sera from mice treated with Ge-132, an organo-germanium compound, to inhibit experimental murine ascites tumors]. 393 51

An inhibitor of interferon action has been identified which is present in IFN-gamma preparations. The inhibitor is produced following rising interferon concentrations in mitogen stimulated mouse spleen cell cultures. Indications are that the inhibitor is produced in response to the production of interferon, and may therefore be a feedback control mechanism for the interferon system. The action of the inhibitor is independent of both interferon type and concentration, and seems to act by preventing the establishment of the interferon-induced antiviral state at some point following the interaction of the interferon molecule with the cell membrane. The inhibitor has an apparent molecular weight of 8,000 to 10,000 daltons and is stable to treatment with low pH, heat, and trypsin. It is proposed that the inhibitor has the specific role in vivo of controlling interferon-mediated activities.
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PMID:Control of the interferon system: an inhibitor of interferon action. 629 94

Studies reported earlier [ Joshi et al. (1982) J. Biol. Chem. 257, 13884-13887] have indicated that human interferon-alpha 2 (HuIFN-alpha 2) binds to a specific macromolecular receptor on human cells as identified by cross-linking with bifunctional cross-linking reagents and analysis by polyacrylamide gel electrophoresis. We have carried out experiments to investigate the fate of the interferon-receptor complex on the cell surface under conditions which lead to cellular response. As analyzed by cross-linking and gel electrophoresis, the interferon-receptor complex, formed on incubation with 125I-IFN-alpha 2 at 4 degrees C, persisted at the cell surface for several hours at 4 degrees C; however, if the cells were switched to 37 degrees C, there was a rapid decline in the complex, apparently due to a loss of the interferon receptors from the cell surface. This was associated with an internalization of the 125I-interferon as indicated by the fact that, on incubation at 37 degrees C, an appreciable fraction of the cell-associated interferon (approximately equal to 50%) became resistant to trypsin digestion, or dissociation on incubation in growth medium or low-pH buffer. A large fraction of the trypsin-resistant (internalized) 125I-labeled material migrated as intact interferon in polyacrylamide gels, and it was immunoprecipitated by anti-(HuIFN-alpha)antibodies but not by anti-(HuIFN-beta)antibodies. The bulk of the internalized 125I-interferon was recovered in a particulate fraction and, on cross-linking with disuccinimidyl suberate, a 150000-Mr complex could be detected. The results suggest that interferon may be internalized as a complex with the receptor, which may account for the loss of the interferon-receptors on the cell surface. This modulation of the IFN-alpha/beta receptors was induced by HuIFN-alpha and HuIFN-beta but not by HuIFN-gamma. The recovery of the IFN-alpha/beta receptors, lost upon incubation with HuIFN-alpha, took several hours and required protein synthesis. The significance of the results is discussed.
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PMID:Interferon receptor interaction. Internalization of interferon alpha 2 and modulation of its receptor on human cells. 632 98

The most marked production of immune interferon by human peripheral blood leukocytes and splenocytes stimulated with phytohemagglutinin (PHA) and staphylococcal enterotoxin A (SEA) was shown to be achieved when lymphoid cells are propagated under conditions of constant sparing mixing on roller apparatus at a temperature of 37 degrees +/- 0.5 degrees C. The resulting interferon was sensitive to low pH, thermolabile, inactivated by treatment with trypsin, and not neutralised by antisera to human alpha- and beta-interferons. The antiviral properties with regard to vesicular stomatitis and Semliki Forest viruses were practically similar in PHA- and SEA-induced interferon and human alpha- and beta-interferons. The capacity to inhibit colony formation by HeLa cells was 30 times higher in gamma-interferon than the antiproliferative activity of alpha- and beta-interferons.
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PMID:[Human immune interferon: production and action]. 632 69

Moderate titres of antiviral activity were demonstrated in 48-58% of sera obtained from patients suffering from seropositive and seronegative rheumatoid arthritis (RA), psoriatic arthritis, Reiter's syndrome, ankylosing spondylitis, and juvenile rheumatoid arthritis. Sera from blood donors and from patients with various noninflammatory diseases were positive in 16% of cases. The activity was species-specific, mediated by the homologous cells, and destroyed by treatment with trypsin and exposure to pH 2. Antibodies against human IFN-alpha did not neutralise the activity. These characteristics are compatible with those of IFN-gamma or immune interferon. Neither the presence nor the titre of IFN was correlated with disease activity defined by concentration of C-reactive protein, C3 concentration, and erythrocyte sedimentation rate. IFN-gamma was present in 4 of 10 synovial fluids from patients with RA. The titre in one of these was higher than in the corresponding serum, indicating local production in the rheumatoid joint.
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PMID:Immune interferon in serum and synovial fluid in rheumatoid arthritis and related disorders. 641 86

An interleukin 2-independent murine T cell line (BFS) was isolated that produced immune interferon after stimulation with phorbol 12-myristate 13-acetate. The BFS cell line did not produce detectable levels of interleukin 1, interleukin 2, B cell growth factor, macrophage-granulocyte colony-stimulating factor, macrophage-activating factor, or T cell replacing factor. Maximal interferon was induced 48 hr after stimulation with phorbol myristate acetate at 10-100 ng/ml. Production of interferon by phorbol myristate acetate-stimulated BFS cell cultures was synergistically increased by the addition of EL4 thymoma cell culture supernatants. BFS-derived interferon activity was sensitive to pH 2 treatment and was neutralized with antiserum to immune interferon but was resistant to heating at 56 degrees C and to treatment with antiserum to type I interferon. In addition, the interferon activity was sensitive to trypsin but resistant to RNase. BFS-derived interferon had an apparent molecular weight of 48,000 and a pI of 5.5-6.0. Each of these properties is consistent with the conclusion that the BFS cell line produces immune interferon after stimulation with phorbol myristate acetate.
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PMID:Production of immune interferon by an interleukin 2-independent murine T cell line. 681 57


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