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)

Rapid progress in studies of cytokines have clarified their roles in processes of lymphocyte proliferation and differentiation. However, the involvement of these molecules in lymphopoiesis during embryonic development has not yet been well documented. In this study we screened for possible existence of cytokines that influence lymphopoiesis in murine amniotic fluid (AF) obtained from non-autoimmune prone "normal" strains of mice (CBA/J, BALB/c, A/J, SWR, and C57B/6) and autoimmune-prone NZB mice. Significant colony stimulating activity-1 (CSA-1)-like activities were found in AF of all of the strains tested, but relatively low activities were present in AF of NZB mice. No interleukin 2 (IL 2) or interleukin 3 (IL 3)-like activities were detected, Weak IL 1-like activity was found in AF of most of the strains tested; however, the results of the standard thymocyte proliferation assays varied with each AF sample. This variation is probably related to the presence of nonspecific inhibitors including alpha-fetoprotein in murine AF. Therefore, pooled AF from CBA and NZB strains of mice were subjected to several purification procedures to assess the actual amount of IL 1-like activity present in murine AF. After (NH4)2SO4 precipitation and hydrophobic phenyl-Sepharose chromatography, the measurable level of IL 1-like activity could be increased significantly. With lentil-lectin affinity chromatography, IL 1-like activity was completely dissociated from CSA-like activity. Moreover, a significantly larger amount of IL 1-like activity was found in NZB AF fractions (approximately sixfold higher). Apparent pI values estimated by preparative isoelectric focusing (IEF) were 5.9, 7.2, and 7.4 in CBA AF fractions, and 6.5 and 7.3 in NZB AF fractions. The NZB AF fraction with pI of 7.3 showed significantly higher IL 1 activity than the other fractions studied. These partially purified molecules were found to be resistant to pH 2 and the reducing agent, 2-mercaptoethanol, but were inactivated by heat (56 degrees C, 1 hr) or trypsin. None of the fractions showed IL 2-like activity but some that had IL 1-like activity induced IL 2 production in a IL 1-dependent, IL 2-producing B lymphoma cell line. Apparent m.w. of these IL 1-like activities were 14,000, 14,500, 17,000, 18,000, and 21,000 in CBA AF fractions, and 15,000, 19,000, and 21,000 in NZB AF fractions according to SDS-polyacrylamide gel electrophoresis.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:IL 1-like activities present in murine amniotic fluid. A significantly larger amount of IL 1 beta-like activity is present in the amniotic fluid of autoimmune NZB mice. 355 25

The human monocytic leukemia cell line THP-1 produces an immunosuppressive factor that inhibits interleukin 1 (IL-1)-dependent proliferation of mouse thymocytes as well as the mitogenic effects of concanavalin A (Con A) and phytohemagglutinin (PHA) on human peripheral blood mononuclear cells. The mechanism of action of this factor includes interference with both the production of interleukin 2 (IL-2) and its effects on target cells. Thus, the suppressor abrogates the proliferation of an IL-2-dependent cytotoxic T cell line (CTLL), but not of IL-2 independent cells like the L929 fibroblasts or the EL4 T lymphoma and U937 histiocytic lymphoma lines. It also suppresses IL-2 production by human peripheral blood enriched T cells and mouse splenocytes. The mediator has a molecular weight of 60,000-70,000 dalton, as determined by gel filtration chromatography, is heat labile, and is sensitive to trypsin, chymotrypsin, and protease.
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PMID:A macrophage-derived factor that inhibits the production and action of interleukin 2. 389 22

Soluble factors that enhance maturation of murine B lineage precursor cells in vitro were partially purified from the serum of very young NZB mice and characterized biochemically and biologically. Activity was initially detected by induction of colony-forming activity and surface immunoglobulin (sIg) on normal sIg- marrow cells as well as responsiveness of a pre-B cell line. Pooled sera from 4- to 5-wk-old NZB mice were initially fractionated on Sephacryl S-300 and Sephadex G-100 superfine columns. Fractions with activity (corresponding to m.w. of 15,000 to 45,000) were pooled and further separated. The activity was eluted as a single peak by hydrophobic (phenyl-Sepharose, with 0.8 M (NH4)2SO4) and lentil lectin affinity chromatography but resolved into three distinct peaks in preparative isoelectric focusing (IEF), with pI values of 3.5, 7.8, and 8.4. The latter two merged into a single peak with a pI value of 8.8 when the sample was further treated with neuraminidase before IEF. These three IEF fractions, each of which were enriched at least 1000-fold in specific activity relative to starting serum, were then characterized. Each was stable at pH 2 but sensitive to trypsin, 10 M urea, and heat treatment (56 degrees C for 1 hr). In nonreduced SDS-poly-acrylamide gel electrophoresis, their mobilities corresponded to m.w. of 17,000 for peak I (pI 3.5), 15,000 for peak II (pI 7.8), and 15,000 for peak III (pI 8.4). Interleukin 1, interleukin 2, interleukin 3, colony-stimulating factor for granulocyte and macrophage progenitors, antiviral, or B cell growth factor type I-like activities were not demonstrable. Peaks II and III, but not peak I, induced Ig secretion of anti-stimulated B cells. Peak I was also less effective than peaks II and III in induction of sIg on an established pre-B cell line. However, all fractions were equally effective in enhancing maturation of normal sIg- B lineage cells. Thus, serum from 4- to 5-wk-old NZB mice contains at least two distinct soluble factors that can enhance the maturation of sIg- B lineage cells in vitro. The biologic and biochemical characteristics of these factors appear to differ from those of previously well-defined cytokines.
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PMID:Humoral factors in very young NZB mice that enhance the maturation of normal B cell precursors. Partial purification and characterization. 392 91

We previously demonstrated the development of a cloned human T cell hybridoma that secretes B cell growth factor (BCGF) in the absence of demonstrable interleukin 2 or B cell differentiation factor. Sephadex gel filtration chromatography demonstrated the m.w. of this factor to be 18 to 20K. The present studies were performed to further characterize the biochemical properties of the molecule and to determine its target cell specificity. Temperature stability studies showed the monoclonal BCGF to be stable at 37 degrees C for 12 hr and at 70 degrees C for 15 min; however, most (93%) of the activity was lost after incubation at 70 degrees C for 30 min. Aliquots of hybridoma supernatant were exposed to buffer solutions with variable pH with no diminution in activity over a pH range of 4.0 to 10.0 BCGF activity was not affected by 2-mercaptoethanol, neuraminidase, or nucleic acid denaturing enzymes. In contrast, all activity was destroyed by 10 M urea, trypsin, and chymotrypsin. Chromatofocusing demonstrated the isoelectric point of BCGF to be 6.3 to 6.6. Finally, absorption experiments demonstrated that BCGF activity was absorbed by large, activated B cells. Mitogen-stimulated T cell blasts, small resting B cells, and CESS cells failed to absorb BCGF activity from the hybridoma supernatant. These and future studies with purified monoclonal human BCGF should enhance our understanding of its immunochemical properties and of its role in the immunoregulation of human B cell responses.
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PMID:Characterization of monoclonal B cell growth factor (BCGF) produced by a human T-T hybridoma. 642 36

In previous studies, cultured melanoma cells were shown to have a suppressive influence on the induction of cytotoxic T cells. Our investigation of the mechanism of these effects revealed that supernatants from certain cultures of melanoma cells contained inhibitory activity against the production of interleukin 2 (IL 2) from phytohemagglutinin (PHA)-stimulated cultures of lymphocytes. These supernatants did not inhibit interleukin 1 production, and also did not inhibit the mitogenic activity of performed IL 2 on IL 2-dependent target cells. Production of the inhibitory activity could be reduced by inhibitors of protein synthesis, but this activity was not inhibited by digestion with the proteolytic enzymes trypsin or pronase. Gel filtration analysis of tumor supernatants revealed that the majority of the inhibitory activity was detected in fractions of approximately 44 and 7 Kd. The addition of supernatants with inhibitory activity to PHA-stimulated cultures of lymphocytes was associated with reduced transition of cells from G1 to S phase of cell division, which could be reversed by the addition of IL 2. Preliminary studies suggest that the release of the factor(s) from melanoma cells may be related to rapid progression of tumor growth in patients, and therefore may be of prognostic significance in tumor host relationships.
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PMID:Inhibition of interleukin 2 production by factors released from tumor cells. 660 93

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

This report describes a simple scheme for the simultaneous purification of cationic human granzymes A, B, and 3 from human interleukin 2 (IL-2)-activated lymphocytes. The process, which requires approximately 8 h, includes: (1) cell cavitation, (2) two centrifugation steps, (3) four granule solubilization steps, and (4) cation-exchange chromatography. Granule solubilization consists of three extractions with a hypotonic buffer (25 mM NaCl) that contained Triton X-100 followed by a final extraction in hypertonic detergent-free buffer (390 mM NaCl). We recovered approximately 35% of the trypsin-like (tryptase) activities mediated by granzymes A and 3, respectively, and approximately 25% of the asp-ase activity of granzyme B. The granzymes were identified after elution from the Mono S column by Western blot with a polyclonal antibody that reacts with a conserved amino acid sequence (9-16) of lymphoid/myeloid serine proteases. By amino-terminal sequencing, eluted granzyme A and B were indeed homogeneous. Granzyme 3, although highly enriched, appears to be contaminated with an uncharacterized granzyme. Although we have developed this scheme to rapidly isolate the granzymes, the procedure should assist the purification of secretory granule-associated cationic proteins that reside in neutrophils and mast cells as well as other cells that possess secretory function.
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PMID:Rapid purification of cationic granule proteases: application to human granzymes. 825 51

Swine interleukin 2 (IL-2) activity was assayed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) colorimetric assay using murine IL-2 dependent cell line (CTLL-2). The culture supernatant of mesenteric lymph node (MLN) cells stimulated with phytohemagglutinin-P (PHA) induced a generation of MTT formazan in a dose-dependent manner, suggesting dose-dependent proliferation of CTLL-2. The maximal swine IL-2 activity was observed in the culture of MLN cells at 1 to 2 x 10(7) cells/ml when stimulated with 20 to 40 micrograms/ml PHA for 48 hr. Based on these findings, a large culture of MLN cells to prepare swine IL-2 were performed under the following condition; cell concentration of 1 x 10(7) cells/ml, PHA concentration of 20 micrograms/ml, a culture scale of 200 to 400 ml, and a stirring speed of 30 rpm. Swine IL-2 activity was detected from 4 hr after PHA stimulation, and rapidly increased until 16 hr. Almost maximal IL-2 activity in stirring culture was observed at the incubation of 20 hr. Swine IL-2 was partially purified by Sephacryl S-200 gel filtration and the estimated molecular weight was about 32 kD based on the peak of IL-2 activity. The pI value of swine IL-2 was estimated to be approximately pH 5.3. Swine IL-2 was sensitive to acid (pH 3.2) or alkaline (pH 10.5), 4 or 8 M urea, trypsin, and the heating at 70 degrees C. These physico-chemical properties of swine IL-2 was similar to those of human, murine or feline IL-2.
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PMID:Swine interleukin 2 activity produced by mesenteric lymph node cells. 828 23

DNA fusions encoding chimeric proteins in which human interleukin 2 (IL2) was fused to the A subunit of the plant cytotoxin ricin (RA) have been expressed in Xenopus oocytes. The constructs contained N-terminal IL2 and C-terminal RA, or N-terminal RA and C-terminal IL2. In the expressed chimeric proteins, the IL2 and RA moieties were joined by a peptide sequence containing a proteolytic cleavage site. Two proteolytically-sensitive peptide sequences were utilized; a peptide that forms the trypsin-sensitive disulfide-bonded loop in diphtheria toxin (DT) or a synthetic peptide containing the factor Xa recognition site in a sequence flanked by two cysteine residues. In an in vitro cell free system the RA component was biologically active in all chimeric proteins produced since it specifically depurinated 28S ribosomal RNA. Proteolytic cleavage of the chimeras with either trypsin or factor Xa as appropriate separated the IL2 and RA moieties, but they did not remain covalently linked by a disulfide bond. Because of this, the cytotoxicity of protease-treated chimeras could not be assessed. Chimeras not pretreated with factor Xa but which contained the factor Xa target sequence were not cytotoxic to CTLL-2 cells. Rather, these molecules had a stimulatory effect that was ascribed to the IL2 moiety. In contrast, recombinant chimeric toxins containing the DT loop sequence were cytotoxic to CTLL-2 cells. Taken together the data suggest that RA-containing chimeras require intracellular proteolytic cleavage to release the RA moiety to render them cytotoxic to target cells.
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PMID:Biologically active interleukin 2-ricin A chain fusion proteins may require intracellular proteolytic cleavage to exhibit a cytotoxic effect. 830 13

The beta-amyloid peptide (A beta) is a normal proteolytic processing product of the amyloid precursor protein, which is constitutively expressed by many, if not most, cells. For reasons that are still unclear, A beta is deposited in an aggregated fibrillar form in both diffuse and senile plaques in the brains of patients with Alzheimer's disease (AD). The factor(s) responsible for the clearance of soluble A beta from biological fluids or tissues are poorly understood. We now report that human alpha2-macroglobulin (alpha2M), a major circulating endoproteinase inhibitor, which has recently been shown to be present in senile plaques in AD, binds 125I-A beta(1-42) with high affinity (apparent dissociation constant of 3.8 x 10(-10) M). Approximately 1 mol of A beta is bound per mole of alpha2M. Both native and methylamine-activated alpha2M bind 125I-A beta(1-42). The binding of 125I-A beta(1-42) to alpha2M is enhanced by micromolar concentrations of Zn2+ (but not Ca2+) and is inhibited by noniodinated A beta(1-42) and A beta(1-40) but not by the reverse peptide A beta(40-1) or the cytokines interleukin 1beta or interleukin 2. alpha1-Antichymotrypsin, another plaque-associated protein, inhibits both the binding of 125I-A beta(1-42) to alpha2M as well as the degradation of 125I-A beta(1-42) by proteinase-activated alpha2M. Moreover, the binding of 125I-A beta(1-42) to alpha2M protects the peptide from proteolysis by exogenous trypsin. These data suggest that alpha2M may function as a carrier protein for A beta and could serve to either facilitate or impede clearance of A beta from tissues such as the brain.
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PMID:alpha2-Macroglobulin as a beta-amyloid peptide-binding plasma protein. 920 23


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