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Biomedical subjects

D G Payan

Publications and source records attributed to D G Payan.

At least 91 records · Page 5Linked to original sources
PubMed1987

Immunoaffinity purification of membrane protein constituents of the IM-9 lymphoblast receptor for substance P.

Substance P (SP) is an undecapeptide neuromediator that stimulates human T-lymphocyte function by binding to stereospecific membrane receptors. Human IM-9 cultured B-lymphoblasts express approximately 20,000 receptors per cell for [125I]SP with a Kd of 0.3 nM. [125I]SP was specifically crosslinked by disuccinimidyl suberate to IM-9 cell membrane proteins of 78, 58, and 33 kDa. An indirect immunoaffinity purification procedure has now been developed based on immunoabsorption of detergent-solubilized [125I]SP-labeled IM-9 cell membrane proteins to anti-SP antibody that was bound to an epoxide ultraffinity high-performance liquid chromatography column, followed by elution in acidic 8 M urea. The 58- and 33-kDa SP-receptor complexes were purified to apparent homogeneity by immunoaffinity chromatography and identified by autoradiography and silver staining of sodium dodecyl sulfate-polyacryl-amide gels.

Affinity Labels↗
PubMed1987

Distribution of substance P receptors on murine spleen and Peyer's patch T and B cells.

Previous studies have demonstrated that the sensory neuropeptide substance P (SP) can modulate immune responses in vitro. Work from this laboratory has shown that SP enhances immunoglobulin synthesis by murine splenic and Peyer's patch lymphocytes stimulated with concanavalin A. One mechanism underlying these effects is the binding of SP to specific receptors on lymphocytes. We examined the distribution of SP receptors on murine T and B lymphocytes and their subsets by one and two color fluorescence-activated cell sorter analysis. The specificity and nature of binding was examined using radiolabeled SP, and competitive inhibition experiments were performed with cold SP. In cytofluorimetry experiments, both T and B lymphocytes from Peyer's patches and spleen were bound to SP, with those from Peyer's patches having a higher proportion than lymphocytes from the spleen. The majority of T cells from both organs bound SP with binding being evenly distributed between Lyt-1+ and Lyt-2+ cells. Similarly, the majority of B lymphocytes from spleen and Peyer's patches showed SP binding. There were no significant isotype-specific differences within any organ. Studies using 125I-labeled SP showed specific binding to all lymphocyte subpopulations examined. SP receptors were fewer in number on cells isolated from spleen than on cells from Peyer's patches although the dissociation constants were similar for all populations examined. These studies demonstrated that SP receptors are present both on murine T and B lymphocytes from Peyer's patches and spleen. There is no evidence for differential SP receptor expression on distinct lymphocyte subsets in spleen or Peyer's patches.

Animals↗
PubMed1987

Specific high-affinity binding sites for a synthetic gliadin heptapeptide on human peripheral blood lymphocytes.

The synthetic peptide containing residues 43-49 of alpha-gliadin, the major protein component of gluten, has previously been shown to inhibit the production of lymphokine activities by mononuclear leukocytes. We now demonstrate using radiolabeled alpha-gliadin(43-49) that human peripheral blood lymphocytes express approximately 20,000-25,000 surface receptors for this peptide, with a dissociation constant (KD) of 20 nM. In addition, binding is inhibited by naloxone and an enkephalin analog, thus confirming the functional correlate which demonstrates inhibition by these agents of alpha-gliadin(43-49) functional effects. Furthermore, B-lymphocytes bind specifically a greater amount of [125I]alpha-gliadin(43-49) than T-lymphocytes. The lymphocyte alpha-gliadin(43-49) receptor may play an important role in mediating the immunological response to alpha-gliadin.

Binding Sites↗
PubMed1987

The mitogenic effects of vasoactive neuropeptides on cultured smooth muscle cell lines.

In order to investigate the relationship between the biochemical pathways that characterize contraction and cell growth, we have studied both contraction, mitogenesis and protein synthesis induced by the vasoactive neuropeptides, substance P (SP), calcitonin gene related peptide (CGRP) and vasoactive intestinal polypeptide (VIP) on four different established vascular and nonvascular smooth muscle cell lines. Contraction in vitro was evaluated by light microscopy and recorded photographically. Mitogenesis and protein synthesis were evaluated by [3H]-thymidine incorporation into cells and [3H]-amino acid incorporation into trichloroacetic acid precipitated materials, respectively. SP stimulated mitogenesis of A7r5 cells (embryonic rat aorta), but failed to induce significant contraction of these cells, whereas, SP induced contraction of cultured adult rat vascular smooth muscle cells (VSMC), but failed to stimulate mitogenesis. CGRP and VIP stimulated mitogenesis and protein synthesis, respectively, of DDT1MF-2 cells (hamster vas deferens), but neither induced contraction of this cell line. All three neuropeptides showed no effect on BC3H1 (mouse smooth muscle-like) cells. These results suggest that neuropeptides with vasoactive properties modulate different stages of cellular mitogenic responses which may be regulated by the degree of maturation of smooth muscle cell.

Animals↗
PubMed1987

Design and application of a versatile triple-laser cell and chromosome sorter.

A high-resolution triple-laser sorter was designed and constructed to provide flexible switchover and high-resolution sorting of cells or chromosomes with any combination of one, two, or three lasers. These features provide a central facility instrument that currently serves multiple users and analyzes different stain combinations with minimal switchover effort between experiments. Improved optics and mounts that focus the three laser beams independently are able to resolve beads and chromosomes better than our previously reported dual-laser sorter. An improved signal collection unit with electronically controlled reference positions can be focused more quickly and precisely for any signal combination. A removable dye laser extends the range of usable fluorochrome labels. A rapid sheath switchover permits sorting of sterile cells and sterile chromosomes sequentially without additional sterilization or reservoir sheath change. Improved dual-laser chromosome resolution is at least as good, analyzing 8,000 chromosomes/s, compared to the previous dual-laser bench at 2,000/s. Stimulated and unstimulated peripheral blood lymphocytes were analyzed according to simultaneous measurements of cell surface receptors labeled with a fluoresceinated neuropeptide and a Texas red-labeled antibody as well as DNA content during the cell cycle. These results demonstrate the broad range of potential applications of this triple-laser system.

Cell Separation↗
PubMed1987

Purification of the 33,000-dalton ligand binding-protein constituent of the lymphoblast substance P receptor.

Substance P (SP) acts as an immunoregulator by binding to specific functional cell surface receptors on a subpopulation of human T-helper lymphocytes. Receptors with similar properties have also been characterized on the human IM-9 B-lymphoblast cell line. Four distinct proteins of molecular weight (MW) 33,000, 58,000, 78,000, and 116,000 can be specifically affinity labeled using [125I]-SP Bolton-Hunter reagent and disuccinymidyl suberate (DSS). Peptide-mapping studies of these individually purified affinity labeled proteins have shown that the 33,000 MW membrane protein is present in the higher molecular weight cross-linked proteins. In the present studies, the 33,000 MW affinity-labeled protein was purified using semipreparative sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) followed by high-performance hydroxylapatite chromatography. Starting with 800 mg of affinity-labeled protein, the final yield was 39.0 micrograms of 33,000 MW affinity-labeled protein. Based on an estimate of 53 mg receptor per 800 mg membrane protein, this represents an overall yield of greater than 70%. Peptide mapping was done by digesting 20 micrograms of the receptor protein with bovine trypsin. The proteolytic fragments were separated by reverse-phase high-performance liquid chromatography, and the amino acid content of 13 distinct peptides was determined. With this procedure, sufficient receptor can now be purified so that partial amino acid sequences can be obtained for further structural studies.

Amino Acids↗
PubMed1987

Interleukin-3 modulation of mouse bone marrow derived mast cell receptors for somatostatin.

Receptors for somatostatin (SOM) were identified on mouse bone marrow derived mast cells (MBMMC) and shown to vary in expression with the state of proliferation and differentiation of the MBMMC. Flow cytometric studies of the binding of fluorescein-labeled SOM and concurrent analyses of the binding of [125I]SOM demonstrated that the population of MBMMC capable of recognizing SOM specifically is that exhibiting a proliferative response to interleukin-3. The MBMMC that bound SOM reached a maximal number at 72 hr following the addition of interleukin-3, and were distributed principally in the G2/M phase of the cell cycle. SOM did not influence directly the proliferative responses of MBMMC to interleukin-3. The level of expression of SOM receptors thus may reflect the state of differentiation of mast cells, as well as determining the functional sensitivity to the inhibitory effects of SOM.

Animals↗
PubMed1987

Distribution of somatostatin receptors on murine spleen and Peyer's patch T and B lymphocytes.

Recent evidence suggests that the neuropeptide somatostatin (SOM) plays an immunoregulatory role. We demonstrated previously that SOM inhibits concanavalin A-induced cell proliferation and immunoglobulin synthesis by murine Peyer's patch and splenic lymphocytes. Available data suggest that these effects are in part mediated by specific SOM receptors expressed by lymphocytes, but as yet these receptors have not been characterized. Using cytofluorimetry we investigated the distribution and specificity of binding of fluorescent SOM (SOM*) to murine Peyer's patch and splenic T- and B-lymphocyte subpopulations. The specificity of binding was confirmed by radioassay. T and B cells from both organs showed specific binding of SOM*. In Peyer's patches, approximately 50% of all cell populations studied (whole, T- and B-cell-enriched) bound SOM specifically and this was significantly higher than the corresponding splenic lymphocyte populations. Eighty to eighty-four percent of Peyer's patch Thy1.2+, Lyt1+, or L3T4+ cells and 94% of Lyt2+ cells bound SOM. Greater than 80% of B cells from this organ bound SOM (sIgA+ = sIgM+ greater than sIgG+ cells). In spleen, approximately 30% of Thy1.2+, Lyt1+, or L3T4+ cells bound SOM and this was significantly less than the proportion of Lyt2+ cells (53%) which did so. More sIgA+ (89%) than sIgG+ (66%) than sIgM+ (55%) B cells bound SOM*. Although we have previously shown that the effect of SOM on immunoglobulin synthesis was relatively isotype-specific (IgA synthesis was predominantly affected, especially in Peyer's patches) this cannot be explained solely on the basis of preferential expression of SOM receptors by distinct lymphocyte subsets. Instead, it is probably the result of the specific immunological microenvironment in which the lymphocytes reside.

Animals↗
PubMed1987

Substance P receptor-dependent responses of leukocytes in pulmonary inflammation.

Pulmonary immunologic responses may be mediated and modulated in part by neuropeptides released from the endings of nerve fibers that innervate the airways. Bronchoconstriction, mucosal edema, and increased airway secretions may be mediated by multiple locally generated neuropeptides. The neuropeptides affect directly and indirectly through other mediators the functions of endothelial cells, smooth muscle cells, blood vessels, and leukocytes. The high content of diverse potent neuropeptides in the ganglionated plexuses close to pulmonary smooth muscle bundles, along blood vessels, and in neural projections into the bronchial epithelium and regions containing acini of mucus glands provide tissue concentrations well within the range required to attain such biologic effects. The airway responses mediated principally by neuropeptides exhibit unique mechanisms of specificity attributable to the selective distribution of each neuropeptide in a distinct subset of nerve fibers that react differently to each stimulus and to the target cell specificity of the neuropeptides. At physiologically relevant in vitro concentrations, many of the neuropeptides have different effects on mast cells, basophils, monocytes, and lymphocytes. The direct actions of substance P (SP) and the capacity to initiate and modulate leukocyte responses are described in relation to the physiologic and pathopharmacologic consequences of pulmonary nerve stimulation. Selected cellular and molecular characteristics of the interactions of SP with mast cells, basophils, lymphocytes, endothelial cells, and smooth muscle cells also will be presented in order to define the functionally critical properties of receptors for the neuropeptide and to expose possible means of specifically modifying the interactions.

Animals↗
PubMed1987

Substance P and immunoregulation.

Peptides released from peripheral nerve endings in mammals, including the tachykinin substance P (SP) and vasoactive intestinal polypeptide (VIP), are potent mediators of smooth muscle and vascular functions. Significant neurophysiological activities of SP and VIP include the transmission of nociceptive and interneuron excitatory signals, respectively. SP has been shown to modulate distinct immediate hypersensitivity responses by stimulating the generation of arachidonic acid-derived mediators from mucosal mast cells but not basophils. Functions of mononuclear and polymorphonuclear leukocytes that characterize the inflammatory response and that are altered by SP include chemotaxis, lysosomal enzyme release, and phagocytic activities. The effects of SP on cell-mediated immunity are largely stimulatory, in that synthesis of DNA, protein, and immunoglobulin by mature T and B lymphocytes, respectively, is significantly enhanced at nanomolar concentrations of the neuropeptide. Functionally relevant receptors for SP on T lymphocytes have been demonstrated by cell sorter and radioligand-binding techniques, and the lymphocyte membrane proteins that comprise the SP receptor are currently being isolated and purified to homogeneity. The characterization of the structure of the SP lymphocyte receptor and identification of the receptor gene will permit detailed analyses of the molecular interactions between the immune and nervous systems.

Animals↗
PubMed1986

Binding characteristics and affinity labeling of protein constituents of the human IM-9 lymphoblast receptor for substance P.

The neuropeptide substance P (SP) stimulates human T-lymphocyte function in vitro. Human blood T-lymphocytes and cultured human IM-9 B-lymphoblasts express 7,000-10,000 and 25,000-30,000 substance P receptors per cell, respectively. The specific binding of 125I-SP is retained in IM-9 lymphoblast membranes solubilized in 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid (CHAPS) at a detergent-to-protein ratio of 1.0. In addition, specific and reversible SP binding to soluble IM-9 cell membrane proteins is demonstrated by gel filtration. The saturation of binding of 125I-SP to both intact and solubilized IM-9 cell membranes attained a steady state after 40-50 min at 4 degrees C. Scatchard analysis of the concentration dependence of 125I-SP binding to IM-9 cell membranes revealed a KD of 0.87 +/- 0.8 nM (mean +/- S.D., n = 4), which is similar to that observed in intact cells, and a density of receptors of 21 +/- 3 fmol/mg of membrane protein (mean +/- S.D.). Binding of 125I-SP to solubilized membranes demonstrated a KD of 0.75 +/- 0.33 nM (mean +/- S.D., n = 3) and a density of receptors of 3.7 +/- 1.5 fmol/mg of membrane protein (mean +/- S.D., n = 3). Affinity cross-linking of 125I-SP by disuccinimidyl suberate to intact IM-9 cells and membranes revealed specifically labeled proteins of Mr 58,000 and 33,000 in cells, and 58,000, 33,000, and 16,000 in membranes by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under both reducing and nonreducing conditions. Competitive effects of substituent peptides of SP on cross-linking and 125I-SP binding to membranes demonstrated that the SP receptor recognized the carboxyl-terminal domain of the peptide. Membranes from cells preincubated in vitro for 12 h at 37 degrees C with 10(-8) M SP demonstrated a decrease in SP receptor density to 13 +/- 2 fmol/mg (mean +/- S.D., n = 2), and a parallel diminution in the specific labeling of membrane proteins of Mr 58,000 and 33,000. These observations suggest that solubilization in CHAPS preserves the binding characteristics of the IM-9 lymphoblast receptor for SP, and that affinity cross-linking techniques identify by sodium dodecyl sulfate-polyacrylamide gel electrophoresis membrane proteins that are specifically labeled by SP.

Affinity Labels↗
PubMed1986

Development of receptors for leukotriene B4 on HL-60 cells induced to differentiate by 1 alpha,25-dihydroxyvitamin D3.

The incubation of HL-60 human promyelocytic leukemia cells for 7 days with 100 nM 1 alpha,25-dihydroxyvitamin D3 [1,25(OH)2D3] induced differentiation into monocyte-like cells, as assessed by morphologic and biochemical characteristics. Stereospecific receptors for leukotriene B4 (LTB4) developed on the surface of the HL-60 cell-derived monocytes that had the capacity to transduce LTB4 stimulation of a transient increase in the cytosolic concentration of calcium ([Ca+2]in). HL-60 cell-derived monocytes, but not undifferentiated HL-60 cells, expressed a high affinity subset of 6400 +/- 3700 receptors per cell with a dissociation constant (Kd) of 2.3 +/- 1 nM (mean +/- SD, n = 3) and a low affinity subset of approximately 2.2 X 10(6) receptors per cell with an apparent Kd of 680 +/- 410 nM. Derivatives of LTB4 inhibited the binding of [3H]LTB4 to HL-60 cell-derived monocytes with a rank order of potency of LTB4 greater than 20-OH-LTB4 greater than 3-aminopropyl amide-LTB4, which is similar to the order for LTB4 receptors of human blood PMNL. In contrast, leukotrienes C4 and D4 and formyl-methionyl chemotactic peptides did not inhibit the binding of [3H] LTB4, which demonstrates the specificity of these receptors for isomers of 5,12-dihydroxy-eicosatetraenoic acid. LTB4 stimulated an increase in [Ca+2]in in HL-60 cell-derived monocytes which reached 50% of the maximal level at an LTB4 concentration of 0.5 nM (EC50). Preincubation of HL-60 cell-derived monocytes with 10 nM LTB4 resulted in a selective loss of high affinity receptors, as assessed by binding of [3H]LTB4, and a 200-fold increase in the EC50 for stimulation by LTB4 of increases in [Ca+2]in, without alterations in either the low affinity receptors for LTB4 or the responsiveness of [Ca+2]in to formyl-methionyl chemotactic peptides. HL-60 cells that are induced to differentiate into monocytes thus develop stereospecific receptors for LTB4 with binding and transductional characteristics similar to those of human blood PMNL.

Calcitriol↗
PubMed1986

Alterations in human leukocyte function induced by ingestion of eicosapentaenoic acid.

Two groups of six adults with persistent asthma, who were identical clinically, received 0.1 or 4 g of purified eicosapentaenoic acid ethyl ester (EPA) daily for 8 weeks. Both doses increased significantly the generation of leukotriene B5 (LTB5) from EPA by polymorphonuclear (PMN) and mononuclear leukocytes, while only the high dose decreased leukocyte arachidonic acid (AA) and the generation of LTB4 and prostaglandin E2 from AA. Only the high dose led to inhibition of PMN leukocyte chemotaxis to multiple stimuli by a mean of 57-70% (P less than 0.01), without altering monocyte chemotaxis, the production of platelet-activating factor by mononuclear leukocytes, or the IgE-dependent release of histamine from basophils. Both doses of EPA increased the responses of T lymphocytes to phytohemagglutinin by a mean of 73% or more (P less than 0.01) without modifying the numbers of helper and suppressor T lymphocytes. EPA affects the functions of several types of leukocytes critical to inflammation and immunity.

Administration, Oral↗
PubMed1986

Abnormal responses to aspirin of leukocyte oxygenation of arachidonic acid in adults with aspirin intolerance.

The effect of 1 microM and 5 microM aspirin on oxygenation of arachidonic acid in vitro by basophils stimulated with anti-IgE was assessed with basophil-enriched suspensions of mononuclear leukocytes from five patients with asthma and hypertrophic allergic rhinitis and one patient with rhinitis alone who had recent adverse pulmonary reactions to aspirin, four aspirin-tolerant patients with asthma receiving therapy similar to that of the aspirin-sensitive patients, and eight normal subjects who resembled the patients with respect to sex and age. As quantified by the combined application of high-performance liquid chromatography and radioimmunoassays, the generation of the principal products prostaglandin E2 (PGE2) and leukotriene D4 was modified differently by aspirin but not sodium salicylate in the aspirin-sensitive patients. The alterations of PGE2 generation and of the ratio of leukotriene D4 to PGE2 generation by aspirin were much greater for basophil-containing leukocytes of aspirin-sensitive patients than those of the two control groups. Although the basic mechanism and relevance to pulmonary reactions of the observed effects of aspirin were not elucidated, aspirin clearly modifies the leukocyte oxygenation of arachidonic acid differently in aspirin-sensitive patients.

Adult↗