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

---

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

To evaluate subclass specificity and aggregate size requirements of IgG receptors on mouse cells, we measured binding of radiolabeled monomeric and BDB-aggregated mouse myeloma proteins fractionated into various sizes by means of gel filtration. Monomers, tetramers, and high molecular weight (approximately 10(7) daltons) aggregates were used. The various cells and cell lines studied could be segregated into three patterns of reactivity: (a) Macrophage and macrophage-like cell lines bound monomer IgG2a preferentially; high molecular weight IgG aggregates bound as follows: IgG1 = IgG2b = IgG2a. (b) Lymphoid lines D2N and S49 showed no capacity to bind monomer IgG2a; high molecular weight aggregates bound as follows: IgG1 = IgG2b less than IgG2a. (c) Other Thy-1-positive lymphoid cell lines (EL4 and L5178) and normal T and B cells showed no capacity to bind monomer IgG; high molecular weight IgG aggregates bound to a lesser extent than to cells of the first two categories in the following manner: IgG1 less than IgG2b greater than or equal to IgG2a. The variable pattern of reactivity of the macrophage-like cell lines with monomer and aggregated IgG suggested that two distinct receptors for IgG were present: one capable of binding IgG2a and another capable of binding all aggregates. Further evidence for this hypothesis was obtained by analysis of the inhibitory capacity of different IgG subclasses on the binding of aggregated IgG and monomer IgG2a to P388 cells. Inhibition of monomer IgG2a binding was effected only by monomer or aggregated IgG2a, whereas inhibition of binding of aggregated IgG1 or IgG2b was noted with aggregates of all three subclasses with some preferential inhibition by monomer IgG2b being observed. Furthermore, monomer IgG2b binding was preferentially inhibitable by monomer IgG2b. It is postulated from these data that two receptor sites are present on this macrophage-like cell line, one reactive with aggregates of all three subclasses as well as monomer IgG2b, and another receptor specific for monomer IgG2a which also binds aggregated IgG2a. Support of this concept was obtained by trypsinization experiments in which the binding of monomer IgG2a was markedly decreased by trypsin treatment of cells, whereas the binding of aggregated IgG2b was unaffected by this treatment.
...
PMID:Receptors for IgG: subclass specificity of receptors on different mouse cell types and the definition of two distinct receptors on a macrophage cell line. 30 Jul 83

Studies were carried out to investigate the nature of the lymphocyte membrane receptor involved in the specific lysis of [51Cr]EL4 target cells by BALB/c cytotoxic peritoneal exudate lymphocytes (PEL) in vitro. In confirmation of earlier related studies, the cytolytic reaction is markedly inhibited by trypsin treatment (1 mg of trypsin/10(6) PEL/ml; 37 C for 30 min) of the PEL. Trypsinized PEL recover their cytolytic activity after 6 hr of incubation in trypsin-free medium at 37 C; recovery is suppressed at 4 C. Significantly, trypsinization of PEL inhibits their ability to adsorb to EL4 target monolayers, indicating that lymphocyte-target cell binding is a trypsinsensitive step of the cytolytic interaction. Specificity of binding for EL4 is restored upon recovery from trypsin treatment. In addition, trypsin treatment, under conditions sufficient to inhibit cytolysis, causes a drastic nonspecific deletion of iodinatable membrane species from the surface of PEL. Thus, a direct correlation between altered cytolytic function and membrane structure cannot be made. Interestingly, trypsinized PEL retain the capacity to kill EL4 to which they are agglutinated by concanavalin-A, suggesting that the lytic mechanism, as distinguished from the binding receptor, is still intact. Papain and pronase also have an inhibitory effect on cytolysis, while neuraminidase causes a significant augmentation of lymphocyte-mediated cytolysis.
...
PMID:Functional characterization of membrane components of cytotoxic peritoneal exudate T lymphocytes. II. Trypsin sensitivity of the killer cell receptor. 108 Jun 13

We have purified the 31-kDa precursor of human interleukin 1 beta (proIL1 beta) from recombinant Escherichia coli expressing the protein. The recombinant precursor was characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, spectroscopy, Western blot, and for biological and receptor binding activity. The protein migrates at the expected molecular weight on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and analytical gel filtration columns. The specific activity of the recombinant precursor is less than 10(2) units/mg in the EL4 thymoma assay compared with 5 x 10(8) units/mg for the recombinant 17-kDa mature protein. The inactivity of the precursor is attributable to the inability of the protein to bind the IL1 receptor on EL4 cells as shown by receptor competition studies using 125I-labeled 17-kDa IL1 beta. Inactivity of the IL1 beta precursor is not due to degradation of the protein in either the bioactivity or receptor binding assays. The inactive IL1 beta precursor is converted to an active form following proteolysis with chymotrypsin which generates a carboxyl-terminal fragment of 17 kDa that is 6 orders of magnitude more active than the starting IL1 beta precursor. Removal of the first 114 amino acids from proIL1 beta generates a fully active molecule. In contrast, removal of the first 77 amino acids by treatment with trypsin only partially restores activity. The resultant 22-kDa protein exhibits a 600-fold increase in both biological and receptor binding activity, demonstrating a direct correlation between the ability of sequences within the pro-region to inhibit biological activity and inhibit binding to the IL1 receptor. Far-UV circular dichroism spectroscopy indicates that proIL1 beta is similar in secondary structure to mature IL1 beta; both proteins are nonhelical beta sheet proteins.
...
PMID:Purification and characterization of human recombinant precursor interleukin 1 beta. 264 2

In oxidation-dependent cytotoxicity (ODCC), cytolytic T lymphocytes (CTL) non-specifically recognize, bind to and lyse oxidized target cells (O-TC) but the precise mechanism whereby CTL react with O-TC is far from clear (Berke, G., Immunol. Rev. 1983. 72:5). Here we present evidence that CTL/O-TC interactions are blocked by aldehyde-reactive reagents such as hydroxylamine, adipic acid dihydrazide and thiocarbohydrazide and that preformed CTL/O-TC conjugates dissociate upon reduction with NaBH4, suggesting that active aldehyde groups of O-TC rather than intercellular Schiff bases are involved in the recognition and lysis of O-TC by CTL in ODCC. The aldehydes are bound to trypsin-sensitive, non-H-2 glycoproteins that appear to be different and unique in the three different target cell lines so far examined (EL4, L1210, R1.1). In view of these and previous findings we would like to suggest that in ODCC, active aldehydes react with adjacent major histocompatibility complex and perhaps other cell-surface molecules to create a multitude of modified conformations, responsible for the "polyclonal" (nonspecific) MHC recognition and lysis of O-TC by CTL, as well as for an altered pattern of H-2 antibody binding to O-TC.
...
PMID:Interaction of periodate-oxidized target cells and cytolytic T lymphocytes: a model system of "polyclonal MHC recognition". 301 6

Rat antiserum (as well as purified IgG and F(ab')2 fragments) raised against cellfree cytosolic extracts (CFE) of an alloimmune cytotoxic T lymphocyte (CTL) clone (B6.1.SF.1) is a potent inhibitor of CTL-mediated cytotoxicity. Inhibition by this antiserum (termed alpha CTLL) occurred during the postbinding lethal hit stages of cytolysis, because it did not inhibit target cell binding, nor did it prematurely dissociate CTL-target cell conjugates; inhibition was observed regardless of the H-2 haplotype of the target cell or CTL employed; inhibition was reversible when pretreated, and washed CTL were used as effectors; and in Ca++ pulse experiments alpha CTLL inhibited cytolysis beyond the Ca++-dependent (lethal hit) stage of cytolysis. This antiserum did not inhibit lysis of P815 cells by activated murine macrophages or by human cytotoxic cells, and extensive absorption of the antiserum on viable thymocytes, normal spleen cells, or CTL did not reduce its blocking activity. CFE prepared from several sources of CTL, including in vivo elicited peritoneal exudate lymphocytes (PEL), secondary MLC-generated CTL, alloimmune splenic T cells, and CTL clones, contained material(s) that inhibited the ability of alpha CTLL to block CTL-mediated cytolysis. The inhibitory activity was not detected in CFE from a variety of noncytotoxic cell sources, including thymocytes, normal C57BL/6 spleen cells, EL4 or P815 tumor cells, macrophages, and helper T cell clones. It was also absent in CFE prepared from human CTL cells. Furthermore, although alpha CTLL neutralizing activity was not detectable in CFE prepared from memory CTL, it rapidly appeared in CTL parallel to the development of cytolytic activity during secondary MLC cultures. The inhibitory material in CTL-CFE appeared to be specific for alpha CTLL antibody, as it did not affect the CTL blocking activity of anti-Lyt-2 or anti-target cell antisera. Finally, CTL-CFE did not contain proteases that degraded the alpha CTLL antibody. By the use of a soluble-phase immunoabsorbent assay, the biochemical properties of materials present CFE derived from CTL and reactive with alpha CTLL antibody were examined. CTL cytosolic material(s) reactive with alpha CTLL IgG was unstable to brief heating (50 degrees C) or acidic pH, but not to high ionic strength buffers. The material was inactivated by treatment with pronase but not by DNase, collagenase, or trypsin. Gel filtration chromatography of CTL-CFE revealed multiple peaks of alpha CTLL neutralizing activity.(ABSTRACT TRUNCATED AT 400 WORDS)
...
PMID:Studies on the cytolytic attack mechanism of the cytotoxic T lymphocyte (CTL): preparation of antisera against cellfree cytosolic extracts of a CTL clone capable of blocking the lethal hit stage of CTL cytolysis and analysis of the cytolytic structure. 315 7

Human lymphoblastic leukemia cells of line CEM-C7 are glucocroticoid-sensitive and contain glucocorticoid receptors of wild-type characteristics. EL4 mouse lymphoma cells are resistant to lysis by glucocorticoids due to mutant receptors that exhibit abnormal DNA binding. Hybrids between the two cell lines were prepared and analyzed with respect to glucocorticoid responsiveness and to receptor types by DNA-cellulose chromatrography. Sensitive hybrid cell clones contained the CEM-C7-specific receptor in addition to the EL4 type of receptor. Several sensitive hybrid cell clones were used for selection of resistant segregants by growth in the presence of high concentrations of glucocorticoid. These segregants had lost the wild-type CEM-C7 receptor, while the EL4-specific receptor was retained. To identify the human chromosome that was lost concordantly with the CEM-C7 receptor the chromosomes of hybrid cells were studied by alkaline Giemsa (G-11) staining and trypsin/Giemsa banding. All hybrids contained human chromosomes in addition to one to two sets of EL4 chromosomes. Human chromosome 5 was present in all hybrid cell clones that expressed the CEM-C7 receptor and it was absent from those that did not. This absolute correlation was not observed for any other human chromosome. We conclude that the human gene for the glucocorticoid receptor is located on chromosome 5.
...
PMID:Assignment of the human gene for the glucocorticoid receptor to chromosome 5. 385 47

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.
...
PMID:A macrophage-derived factor that inhibits the production and action of interleukin 2. 389 22

Peritoneal exudate cells (PEC), obtained after the rejection of EL4 leukemia by BALB/c mice, are much more effective in the specific in vitro destruction of (51)Cr-labeled EL4 cells than are spleen, thymus, lymph node, or peripheral blood lymphocytes. The presence of a large number of effector cells at the site of graft rejection is reflected in the potent cytolytic activity seen in vitro. Effector cells temporarily lose cytolytic reactivity when treated with trypsin but regain reactivity with time. This recovery occurs in normal as well as in immune serum. The destructive reactivity of PEC is increased when macrophages are removed. The remaining population of nonadherent PEC is composed primarily of small- to medium-sized lymphocytes. Complex tissue culture media are not needed, but there is a definite requirement for serum. The required serum component is heat stable, nondialyzable, and is not consumed during the reaction. The use of an ascites allograft system made these observations possible and permitted the isolation of those host cells intimately associated with rejection.
...
PMID:Rejection of ascites tumor allografts. I. Isolation, characterization, and in vitro reactivity of peritoneal lymphoid effector cells from BALB-c mice immune to EL4 leukosis. 502 38

Peritoneal macrophages obtained from normal CBA mice expressed significant cytotoxicity against the DBA/2-derived P815 mastocytoma but not against DBA/2-derived SL2 tumor or the C57BL-derived tumors TLX9 and EL4. The macrophages also expressed some cytotoxicity against the DBA/2-derived L5178Y tumor. Incubation of normal CBA macrophages with cell-free exudate of intraperitoneally growing P815 cells resulted in cytotoxicity against the SL2 and against the EL4 lymphosarcoma. Incubation of SL2 tumor cells with P815 ascitic fluid before adding the SL2 tumor cells to normal CBA macrophage monolayers also resulted in inhibition of SL2 tumor cell growth on these monolayers. Trypsinization of the macrophages after incubation with ascitic fluid (or tumor extract) but before challenge with tumor cells abolished cytotoxic activity of the macrophages. Incubation of normal macrophages with a comparable amount of trypsin before tumor cells were added had no influence on their activity. Cytotoxicity could be induced after 7 days storage of the exudate at 5 degrees C, but this ability was lost within 72 hr when kept at room temperature. Storage at -20 degrees C had no influence. Gel fractionation of the cell-free exudate showed that the product responsible for the effect is a small molecular weight product (mol wt less than 1000). Furthermore the "product" was dialyzable. The "factor" could not be shown in the supernatant of P815 cell cultures unless the cultures comprised greater than or equal to 40% dead cells.
...
PMID:Murine macrophage cytotoxicity induced by mastocytoma cells, cell-free mastocytoma exudates, and extracts. 679 44

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.
...
PMID:Production of immune interferon by an interleukin 2-independent murine T cell line. 681 57


1 2 Next >>

---