PubMed Health⌕ Search

Biomedical subjects

J M Decker

Publications and source records attributed to J M Decker.

At least 19 recordsLinked to original sources
PubMed1991

Evidence that specific high mannose structures directly regulate multiple cellular activities.

Previous studies have demonstrated that much of the immunomodulatory activity of the glycoprotein uromodulin can be attributed to attached oligosaccharides. Structural studies of isolated and purified saccharides derived from uromodulin suggest that the structure Man6GlcNAc2-asn can inhibit in vitro assays of antigen driven T cell proliferation. Based on these observations, we isolated a series of high mannose glycopeptides from a variety of natural sources and tested them for biological activity in a number of assays. We found that purified mannose rich glycopeptides are able to activate the hexose monophosphate (HMP) shunt, induce prostaglandin synthesis, and directly stimulate IL-1 synthesis. These in vitro effects appear to have in vivo counterparts. Thus in a species-restricted fashion, high mannose compounds are able to directly activate a delayed mononuclear cell infiltrate after intradermal injection. Our data suggest that specific mannose oligosaccharides may activate as well as inhibit cellular immune responses at several different levels. These findings support the hypothesis that specific saccharide structures could participate in the physiologic regulation of the immune response.

Animals↗
PubMed1990

Pregnancy-associated changes in oligomannose oligosaccharides of human and bovine uromodulin (Tamm-Horsfall glycoprotein).

The urinary glycoprotein uromodulin (Tamm-Horsfall glycoprotein) exhibits a pregnancy-associated ability to inhibit antigen-specific T cell proliferation, and the activity is associated with a carbohydrate moiety [Muchmore and Decker (1985) Science 229:479-81; Hession et al., (1987) Science 237:1479-84; Muchmore, Shifrin and Decker (1987) J Immunol 138:2547-53]. We report here that the Man6(7)GlcNAc2-R glycopeptides derived from uromodulin inhibit antigen-specific T cell proliferation by 50% at 0.2-2 microM, and further studies, reported elsewhere, confirm that oligomannose glycopeptides from other sources are also inhibitory, with Man9GlcNAc2-R the most inhibitory of those tested [Muchmore et al., J Leukocyte Biol (in press)]. In this work, we have extended the observation of pregnancy-associated inhibitory activity to a second species, and have compared the oligomannose profile of Tamm-Horsfall glycoprotein (nonpregnant) with that of uromodulin (pregnant) derived from both human and bovine sources. Surprisingly, there was a pregnancy-associated decrease in the total content of oligomannose chains due predominantly to a reduction in Man5GlcNAc2-R and Man6GlcNAc2-R. Man7GlcNAc2-R, which did not decrease with pregnancy, comprised a significantly greater proportion of the total oligomannose chains in pregnant vs. nonpregnant samples from both species (human; 34.6% vs. 25.9%: bovine; 14.4% vs. 7.2%).

Animals↗
PubMed1989

IL-2, a lectin with specificity for high mannose glycopeptides.

Utilizing a solid phase binding assay, we have demonstrated that rIL-2 binds with high affinity to the human urinary glycoprotein uromodulin. This binding is specifically inhibited by the saccharides diacetylchitobiose and Man(alpha 1-3)(Man(alpha 1-6]Man-O-methyl and by the high mannose glycopeptides Man5GlcNAc2-R and Man6GlcNAc2-R, but not by Man9GlcNAc2-R. rIL-2 also binds OVA, a glycoprotein which contains approximately 50% high mannose chains at a single glycosylation site, and to yeast mannan. This binding is inhibited by the same battery of saccharides which inhibit the binding to uromodulin. The conclusion that rIL-2 is a lectin is further supported by the observation that the sequence of IL-2 shares 27% homology with a 33-residue sequence of the carbohydrate-binding domain of human mannose-binding protein. The potential physiologic relevance of the carbohydrate binding activity is further elucidated by studies which show that 1) binding of soluble rIL-2 to immobilized uromodulin is enhanced at a pH of 4 to5 in the presence of divalent cations, and 2) neither uromodulin nor the high mannose glycopeptide Man5GlcNAc2Asn blocks the binding of rIL-2 to the IL-2R. Thus the carbohydrate-binding site of rIL-2 is distinct from the cell surface receptor-binding site, and might function preferentially in acidic microenvironments.

Amino Acid Sequence↗
PubMed1988

The lectin-like interaction between recombinant tumor necrosis factor and uromodulin.

The polypeptide of uromodulin, an immunosuppressive glycoprotein isolated from human urine, has been shown to be identical to that of Tamm-Horsfall glycoprotein and is synthesized exclusively in the kidney (Hession, C., Decker, J. M., Sherblom, A. P., Kumar, S. (1987) Science 237, 1479-1484). Uromodulin binds recombinant murine interleukin 1 alpha with high affinity, and this binding can be inhibited by addition of specific saccharides (Muchmore, A. V., and Decker, J. M. (1987) J. Immunol. 138, 2541-2546). We now report that uromodulin binds recombinant human tumor necrosis factor (rTNF) with high affinity. Both diacetylchitobiose and Man(alpha 1-6)(Man(alpha 1-3]-Man-O-ethyl are effective inhibitors of the binding, whereas a wide variety of other saccharides are not inhibitory. Although Tamm-Horsfall glycoprotein contains predominantly tetraantennary N-linked chains, the binding to rTNF is unaffected by removal of terminal sialic acid, galactose, and N-acetylhexosamine residues. Fractionation of a Pronase digest of uromodulin by gel filtration yields material that inhibits the binding of uromodulin to rTNF but is of lower molecular weight than the major oligosaccharide. Uromodulin does not inhibit the cytotoxic activity of rTNF as monitored by lysis of tumor cell targets but effectively protects mice from lethal challenge with lipopolysaccharide, an event that may involve lymphokine toxicity. We have previously shown that rTNF binds to sections of human kidney and is localized in the same region as uromodulin. Thus, rTNF interacts with uromodulin via carbohydrate chains that are less processed than the major tetraantennary chain, and this interaction may be critical in promoting clearance and/or reducing toxicity of TNF and other lymphokines.

Animals↗
PubMed1987

Uromodulin (Tamm-Horsfall glycoprotein): a renal ligand for lymphokines.

The protein portion of the immunosuppressive glycoprotein uromodulin is identical to the Tamm-Horsfall urinary glycoprotein and is synthesized in the kidney. Evidence that the glycoproteins are the same is based on amino acid sequence identity, immunologic cross-reactivity, and tissue localization to the thick ascending limb of Henle's loop. Nucleic acid sequencing of clones for uromodulin isolated from a complementary DNA bank from human kidney predicts a protein 639 amino acids in length, including a 24--amino acid leader sequence and a cysteine-rich mature protein with eight potential glycosylation sites. Uromodulin and preparations of Tamm-Horsfall glycoprotein bind to recombinant murine interleukin-1 (rIL-1) and human rIL-1 alpha, rIL-1 beta, and recombinant tumor necrosis factor (rTNF). Uromodulin isolated from urine of pregnant women by lectin adherence is more immunosuppressive than material isolated by the original salt-precipitation protocol of Tamm and Horsfall. Immunohistologic studies demonstrate that rIL-1 and rTNF bind to the same area of the human kidney that binds to antiserum specific for uromodulin. Thus, uromodulin (Tamm-Horsfall glycoprotein) may function as a unique renal regulatory glycoprotein that specifically binds to and regulates the circulating activity of a number of potent cytokines, including IL-1 and TNF.

Amino Acid Sequence↗
PubMed1987

Evidence that recombinant IL 1 alpha exhibits lectin-like specificity and binds to homogeneous uromodulin via N-linked oligosaccharides.

Uromodulin, a recently described immunosuppressive glycoprotein isolated from human pregnancy urine, has been shown to inhibit T cell proliferative assays dependent upon interleukin 1 (IL 1). We have also recently demonstrated that uromodulin binds specifically to IL 1. We now show that not only the biologic activity but also the binding affinity of uromodulin for recombinant IL 1 is dependent upon intact glycosylation. Furthermore, oligosaccharides isolated from pronase-digested uromodulin are immunosuppressive by themselves and are able to compete with native uromodulin for binding to IL 1. We conclude that recombinant IL 1 exhibits lectin-like specificity, and uromodulin is a biologically functional glycoprotein target of the lectin-like specificity of IL 1.

Carbohydrate Conformation↗
PubMed1987

In vitro evidence that carbohydrate moieties derived from uromodulin, an 85,000 dalton immunosuppressive glycoprotein isolated from human pregnancy urine, are immunosuppressive in the absence of intact protein.

Our laboratory recently reported the purification of a unique immunosuppressive glycoprotein isolated from human pregnancy urine (7). This glycoprotein, which we term uromodulin, has a m.w. of 85,000 as assessed on SDS-PAGE and is 30% carbohydrate. Uromodulin blocks in vitro antigen-specific T cell proliferation to recall antigens such as tetanus toxoid at concentrations as low as 100 pM. This glycoprotein also blocks the in vitro generation of spontaneous monocyte-mediated cytotoxicity (7, 36). Recent evidence strongly suggests that the primary action of uromodulin is to act as a specific ligand and modulator of IL 1 (10, 33). We now report additional biochemical characterization of uromodulin, and based on three independent lines of evidence, find that its immunologic activity appears to result from its glycosylation. First, measures to alter the tertiary folding of the protein backbone of uromodulin, including succinylation or reduction and carboxymethylation, fail to significantly affect its in vitro bioactivity. Second, after extensive digestion of intact uromodulin with pronase, the majority of the in vitro bioactivity can be recovered in a single carbohydrate-rich fraction. Finally, digestion with N-glycanase (N-glycosidase F-, an enzyme specific for N-asparagine-linked oligosaccharides) and subsequent purification on thin layer chromatography yields a single complex oligosaccharide that appears to be responsible for the majority of the in vitro immunosuppression mediated by uromodulin. These data suggest that uromodulin displays N-linked carbohydrate sequences capable of down-regulating antigen-specific T cell responses in vitro. It has been suggested that endogenous lectins may play an important role as recognition molecules in mammalian, as well as more primitive immune systems (23, 24). Our in vitro biologic data strongly suggest that the carbohydrate portion of uromodulin is an excellent candidate to function as a potential lectin receptor.

Alkylation↗
PubMed1986

Binding and mitogenic properties of a galactosyl-specific lectin from the tunicate Didemnum candidum for murine thymocytes and splenocytes.

The affinity-purified major galactosyl-specific lectin (DCL-I) from the tunicate Didemnum candidum binds and induces blastogenesis in untreated and Vibrio cholerae neuraminidase (VCN)-treated murine splenocytes. However, it only binds and stimulates murine thymocytes when they have been pretreated with VCN. Binding and stimulation of VCN-treated splenocytes and thymocytes is specifically inhibited by D-galactose. Binding of lectin to splenocytes is highly increased by the VCN treatment, but the cells are stimulated to the same extent in both untreated and VCN-treated cells. This suggests that although additional DCL-I carbohydrate acceptors are uncovered by VCN treatment of the splenocytes, the ones responsible for triggering blastogenesis are already exposed on the untreated cells. On the contrary, cleavage of terminal sialic acids from the thymocyte cell surface is required to expose DCL-I carbohydrate acceptors in order to obtain a mitogenic response. Our results suggest that the distribution of cell surface galactosyl carbohydrate moieties to which DCL-I binds is different in thymocytes and splenocytes.

Animals↗
PubMed1986

Uromodulin. An immunosuppressive 85-kilodalton glycoprotein isolated from human pregnancy urine is a high affinity ligand for recombinant interleukin 1 alpha.

Uromodulin is an 85-kDa immunosuppressive glycoprotein originally isolated from human pregnancy urine. It exhibits immunosuppressive activity in vitro at concentrations between 10(-9) and 10(-11) M. Recent data demonstrate that uromodulin is able to specifically inhibit in vitro assays dependent upon interleukin 1 (IL-1). We now present evidence that uromodulin is a high affinity ligand for recombinant murine IL-1 alpha. Since uromodulin has been purified to homogeneity, this should allow extensive further characterization of the mechanism of action of both uromodulin and IL-1.

Animals↗
PubMed1985

Uromodulin: a unique 85-kilodalton immunosuppressive glycoprotein isolated from urine of pregnant women.

Crude fractions of urine from pregnant women are immunosuppressive in vitro. An 85-kilodalton immunosuppressive glycoprotein purified to homogeneity from such urine inhibited in vitro assays of human T-cell and monocyte activity at concentrations of 10(-9) to 10(-11) molar. This material was nontoxic and blocked early events required for normal T-cell proliferation in vitro. On the basis of its tissue source and its in vitro activity, the name "uromodulin" is proposed for this glycoprotein.

B-Lymphocytes↗
PubMed1985

Surface expression and partial characterization of an arsonate hapten-specific idiotype-bearing T-cell receptor.

Anti-idiotype antibodies raised against the arsonate hapten idiotype have been used to detect arsonate-binding receptors on the surface of peripheral T cells of A/J mice and to isolate this material after biosynthetic labeling for partial chemical characterization. It was found that 2-3% of splenic T cells from arsonate-immune mice specifically bound the hapten using immunofluorescent keyhole limpet hemocyanin as a carrier. In double-immunofluorescence labeling experiments, a high proportion (approximately equal to 70%) of these cells also bound the (Fab')2 fragment of rabbit anti-idiotype antibody in exactly the same patches on the cell as the arsonate hemocyanin antigen. In addition, the anti-idiotype antibody inhibited the binding of the hapten-carrier complex to T cells by approximately equal to 70%. In parallel experiments, fowl antibodies against mouse (Fab')2 fragments bound to 100% of arsonate-binding T cells in the same cell-surface patches as the hapten, and were capable of inhibiting 100% of the hapten-binding cells. Capping, shedding, and resynthesis experiments indicated that the T cells synthesized their antigen-binding idiotype-bearing receptors. Immunoblots of unreduced detergent extracts of purified splenic T cells developed with anti-idiotype antibodies showed bands at 150,000 and 94,000 Da. Equal amounts of protein extracted from liver and analyzed in the same gels as the T-cell material failed to show any reactivity with anti-idiotype antibodies. To confirm the biosynthetic origin of the idiotype-positive materials, detergent extracts from 75Se-methionine- or [3H]leucine-labeled Con A-treated splenic T cells were reacted with anti-idiotype antibodies and the bound material was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In the presence of 2-mercaptoethanol the major band was at 68,000 Da, with variable minor levels of material at 45,000 Da, while when hapten was used to isolate the receptor a dominant 25,000- to 30,000-Da band was seen. We believe that the higher-molecular-weight materials are multimers of the 25,000-30,000 subunit.

Animals↗
PubMed1979

MICC cytotoxic effector function of human T lymphocyte subpopulations bearing Fc-receptors for IgG and IgM.

Purified subpopulations of human T lymphocytes bearing Fc-IgG and Fc-IgM receptors were studied for their ability to mediate mitogen (PHA) induced cellular cytotoxicity (MICC) to chicken erythrocyte (CRBC) and DBA/Mastocytoma P815Y tumour cell targets. There were marked differences in the ability of the Fc-IgG receptor-bearing T cell (T gamma) and the Fc-IgM (T mu) to mediating MICC to CRBC and P815Y target cells. T gamma cells were very efficient killers of CRBC and T mu cells had no cytotoxic activity to CRBC. On the other hand, both the T gamma and T mu subpopulations were able to mediate MICC to P815Y tumour cell targets.

Cytotoxicity, Immunologic↗
PubMed1979

Synergistic cytotoxicity. II. In vitro arming of monocytes and T cells by a heat labile fraction of human plasma.

In a previous paper we demonstrated that freshly obtained human plasma contain a heat labile nonantibody factor that induced human mononuclear cells to become nonspecifically cytotoxic toward xenogeneic but not allogeneic RBC targets. We now present evidence that this factor has a loose affinity for human monocytes and human T cells and can arm then to kill xenogeneic RBC targets. Furthermore, proteolytic enzymes markedly enhance this arming effect. This ability to be armed by a heat labile component found in fresh human plasma and the fact that proteolytic enzymes markedly enhance cytotoxicity clearly dissociate this model of nonspecific cytotoxicity for previously reported NK models.

Absorption↗
PubMed1979

Spontaneous cytotoxicity. III. Inhibition of human monocyte mediated cytotoxicity by pokeweed mitogen.

We have shown that human mononuclear cells become spontaneously cytotoxic to a variety of erythrocyte targets after 7 days of in vitro culture. This phenomenon of spontaneous cytotoxicity occurs in low concentration of either autologous serum of FCS and is independent of any known stimulant. It does not require exogenous antibody, mitogen, or antigen. Once expressed, the cytotoxic cell has little, if any, specificity. Monocytes appear to be responsible for this observed in vitro cytotoxicity. We now present evidence that the development of spontaneous monocyte-mediated cytotoxicity in vitro is completely reversed by the addition of optimally mitogenic doses of PWM. PWM appears to reverse monocyte-mediated killing by stimulating a potent cell-mediated suppressor. This suppressor cell is radiosensitive and its action is blocked by inhibitors of protein synthesis. In contrast to other mitogen-driven suppressor models, PWM will inhibit spontaneous monocyte-mediated cytotoxicity even when added as late as 6 hr before the end of a 7-day culture.

Cell Separation↗
PubMed1979

Synergistic cytotoxicity. I. Characterization of a heat labile plasma fraction that induces nonspecific cytotoxicity by human mononuclear cells.

The mechanism by which non-immune mononuclear cells recognize invading foreign material and are activated for cytotoxic attack was studied in a model system employing human mononuclear cells, fresh plasma, and 51Cr-labeled xenogeneic target erythrocytes. In these experiments, fresh antibody-depleted plasma or mononuclear leukocytes alone were poorly cytotoxic to xenogenic erythrocytes. However, these target cells were rapidly lysed when both fresh antibody-depleted plasma and mononuclear cells were present in the assay. The plasma factor could not be removed by extensive absorption with the target cells, was present in plasma from hypogammaglobulinemic patients, was heat labile, and was sensitive to incubation with zymosan and cobra venom factor. The "antigen" specificity of this reaction was directed by the serum factor inasmuch as target cells autologous to the effector cells could be killed in the presence of antibody-depleted xenogeneic plasma, but not autologous plasma. These data suggest that an important mechanism for the recognition of "foreigness" by non-immune mononuclear cells is via interaction with a plasma component, possibly a factor related to serum complement.

Absorption↗