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Biomedical subjects

C N Abboud

Publications and source records attributed to C N Abboud.

At least 73 records · Page 4Linked to original sources
PubMed1988

Expression of IgG Fc receptors in myeloid leukemic cell lines. Effect of colony-stimulating factors and cytokines.

Three classes of FcR have been defined on human myeloid cells by their reactivity with mAb; FcRI (mAb 32); FcRII (mAb IV3); and FcRIII (mAb 3G8). We have quantitated the expression of each FcR on human myeloid leukemia cells and cell lines (KG-1, HL-60, U937, and K562). Detailed analysis of FcR surface expression is provided for the U937 cell line after exposure to CSF and cytokines. Increased expression of FcRI and FcRII occurred at 72 h in cells exposed to GCT or Mo cell line-conditioned medium as well as to medium from PHA-treated mononuclear cells. The augmentation of FcRII required protein synthesis and was diminished by a neutralizing antibody to granulocyte-macrophage CSF. We also show that fractions containing natural granulocyte CSF or granulocyte-macrophage CSF as well as r-granulocyte and r-granulocyte-macrophage CSF are capable of inducing FcRII on these cells, whereas other cytokines such as IL-1 and IL-2, TNF-alpha, INF-gamma and macrophages CSF failed to do so.

Antibodies, Monoclonal↗
PubMed1988

Macrophage colony-stimulating factor in nerve growth factor preparations.

Following a report that nerve growth factor preparations have granulocyte-colony-stimulating activity, we investigated the presence of colony-stimulating factors in 7s mouse submaxillary nerve growth factor and its subunits. Macrophage colonies were formed in mouse bone marrow cultures after exposure to preparations of 7s nerve growth factor, the gamma subunit, and, to a small extent, the alpha subunit; the beta subunit, which is responsible for the nerve growth function, did not stimulate colony growth. Furthermore, the esteropeptidase activity of the gamma subunit was not detected in preparations of macrophage colony-stimulating factor purified from the giant cell tumor (GCT) cell line. Immunoprecipitation of radiolabeled gamma subunit with a polyclonal antibody to L-cell macrophage colony-stimulating factor showed a protein band that could represent the gamma subunit of nerve growth factor. Separation of the macrophage activity from the esteropeptidase activity of the gamma subunit was accomplished on the basis of molecular size. Thus, macrophage colony-stimulating factor was a contaminant of nerve growth factor produced by the mouse submaxillary gland and copurified with the gamma subunit.

Animals↗
PubMed1988

Effect of hydrocortisone and interleukins 1 and 2 on eosinophil progenitors in hypereosinophilic states.

The growth of eosinophil progenitors (CFU-Eo) and its modulation by hydrocortisone (HC), mononuclear cells, interleukin 1 (IL-1), and interleukin 2 (IL-2) in three cases of eosinophilia are reported in this paper. One microM HC decreased the proportion of CFU-Eo in each of these three patients, and in each case, the addition of autologous mononuclear cells at a 1:1 ratio abrogated the effect of HC on CFU-Eo. As studied in two of the three cases, IL-1 and IL-2 were able to prevent the effect of HC. Further studies showed no effect of HC when monocyte T cell-depleted marrow cells were used as the target population. These results suggest that CFU-Eo production in eosinophilic states is subject to modulation by HC and T lymphocytes.

Adult↗
PubMed1988

Purification of GCT cell-derived human colony-stimulating factors.

We have purified human-active colony-stimulating factors from the human cell line, GCT, using sequential ultrafiltration; cation exchange, gel permeation, and reverse-phase high performance liquid chromatography (RHPLC); and ion-exchange HPLC. Activity eluted from sodium dodecyl sulfate-polyacrylamide gels with a peak at 17,500 daltons. Similar results were obtained by processing 35S-methionine-labeled conditioned medium, which showed a labeled band in the same region of activity. This purified HPLC fraction, which had a specific activity of greater than 1 x 10(7) colonies/mg protein, stimulated neutrophil colonies at day 7 and neutrophil, neutrophil-macrophage, and eosinophil colonies at day 14 of culture, suggesting that it contained both granulocyte (G-CSF) and granulocyte-macrophage (GM-CSF) colony-stimulating factors. It also promoted the growth of erythroid progenitors, and the GM-CSF fraction purified by hydrophobic chromatography had erythroid-enhancing activity. Separation of G-CSF from GM-CSF was accomplished by the addition of trifluoroacetic acid to the mobile phase at the reverse-phase HPLC step.

Chromatography, High Pressure Liquid↗
PubMed1987

Interactions of dimethyl sulfoxide and granulocyte-macrophage colony-stimulating factors on the growth and maturation of HL-60 cells.

We have studied the interactions of dimethyl sulfoxide (DMSO), Giant Cell Tumor (GCT) cell-conditioned medium (GCT CM), and highly purified granulocyte-macrophage colony-stimulating factors (GM-CSF) on the growth and maturation of a highly passaged population of HL-60 cells. DMSO produced dose-dependent inhibition of HL-60 growth in liquid and semisolid media. Growth was partially to completely restored by the addition of GCT CM to cultures. Experiments in which cell volume, cell cycle kinetics, tritiated thymidine (3HTdr) incorporation, cell number, and nitroblue tetrazolium (NBT) reduction were compared during culture indicated that DMSO inhibited the spontaneous increase in cell volume and flow of cells through the cell cycle which occurred in the first day of culture, the increase in 3HTdr incorporation which was detectable by day 2; and the increment in cell counts which occurred by day 3. These effects were opposed by GCT CM. In contrast, the DMSO-induced increase in NBT reduction which occurred by day 6 was not influenced by GCT CM. The major principle opposing DMSO was GM-CSF, since (1) highly purified GM-CSF from GCT cells and recombinant GM-CSF from COS cells transfected with the Mo cell GM-CSF gene overcame greater than 50% of DMSO inhibition; and (2) conditioned media from cells not producing CSF, G-CSF from GCT cells, and recombinant G-CSF from Escherichia coli transfected with the G-CSF gene from 5,637 cells were inactive. DMSO had little or no effect on the elaboration of autostimulatory activity by HL-60 cells. DMSO is a useful agent for inhibiting the spontaneous growth of HL-60 cells and restoring their dependence on GM-CSF, a property which may be mediated through the effects of DMSO on cell cycle kinetics and/or maturation.

Cell Cycle↗
PubMed1986

Lysis of human fibroblast colony-forming cells and endothelial cells by monoclonal antibody (6-19) and complement.

The murine IgG2a monoclonal antibody 6-19 binds to a wide variety of nonhematopoietic cells including human marrow-derived stromal cells but does not bind to marrow or peripheral blood cells. We studied the effects of this antibody and rabbit complement on marrow cells. Fibroblast colonies were eliminated from light density marrow cells by a single incubation with monoclonal antibody 6-19 and complement. The growth and composition of granulocytic and erythroid colonies were unaffected. Specific complement mediated cytotoxicity of the antibody was confirmed on passaged human fibroblasts derived from marrow (more than 99.6% of fibroblasts are killed by a single treatment). Similar results were obtained with human umbilical cord endothelial cells. In addition, such treatment abolished the initiation of Dexter culture stroma. Incubation of bone marrow cell suspensions with this antibody and complement will allow the study of stroma-free marrow cells in long-term liquid cultures.

Antibodies, Monoclonal↗
PubMed1985

The requirements for ionized calcium and magnesium in lymphocyte proliferation.

The extracellular ionized calcium and magnesium requirements for lectin-induced lymphocyte DNA synthesis were measured in a serum-free system. The use of this system permitted measurements of the ionized calcium and magnesium concentrations with ion-selective electrodes. Maximal DNA synthesis was observed at 270 microM ionized calcium and at 100 microM ionized magnesium in phytohemagglutinin-treated lymphocytes. Lymphocyte DNA synthesis was much more sensitive to reduction of external ionized calcium than to reduction of ionized magnesium. In calcium-free medium (ionized calcium 25 microM), DNA synthesis was reduced by 90%, but in magnesium-free medium (ionized magnesium concentration 7 microM) DNA synthesis was reduced by only 30%. Fifty percent of DNA synthesis stimulated by phytohemagglutinin (PHA) and concanavalin A (Con A) was observed at external ionized calcium concentrations of 97 and 43 microM, respectively. When lymphocytes were stimulated with PHA and the external calcium was chelated with EGTA, 50% inhibition of DNA synthesis was observed at 98 microM ionized calcium. This value agreed well with the free calcium required for PHA activation of DNA synthesis (97 microM). Cytoplasmic calcium, measured with the fluorescent probe Quin 2, increased following lectin exposure if the extracellular ionized calcium concentration was greater than 80 microM. No increase in cytoplasmic calcium could be detected in lectin-treated lymphocytes below 80 microM extracellular ionized calcium, although substantial DNA synthesis was sustained.

Calcium↗
PubMed1985

Modulation of in vitro eosinophil progenitors by hydrocortisone: role of accessory cells and interleukins.

The growth of human eosinophil progenitors (CFU-Eo) and the modulation of growth by hydrocortisone were studied as functions of the presence of lymphocytes and monocytes in marrow cells under study; and the source of colony-stimulating factors, specifically, media conditioned by macrophage-like cell line, GCT; phytohemagglutinin-stimulated mononuclear cells (PHA-LCM); or the T cell line, MO. CFU-Eo growth was greatest in marrow containing accessory cells as compared to marrow depleted of accessory cells; and in marrow treated with phytohemagglutinin-stimulated leukocyte conditioned media (PHA-LCM) or MO (T cell line)-conditioned medium (MO-CM) as compared with GCT cell-conditioned medium (GCT-CM). Hydrocortisone reproducibly inhibited eosinophil progenitor growth in unfractionated marrow stimulated by GCT-CM. This effect was abrogated by admixing irradiated mononuclear cells or T lymphocytes with the target marrow or by adding interleukin 1 or interleukin 2 (IL-1, IL-2). Inhibition by hydrocortisone did not occur when monocyte and T lymphocyte depleted marrow was studied. Unlike GCT-CM, MO-CM and PHA-LCM stimulated equal proportions of eosinophil progenitors in nondepleted and accessory cell-depleted marrow and demonstrated less hydrocortisone inhibition. However, both GCT-CM and PHA-LCM produced in the presence of hydrocortisone stimulated significantly fewer CFU-Eos in both unfractionated and accessory cell-depleted marrow target populations. These results indicate that the growth of CFU-Eo and inhibition of growth by hydrocortisone is a direct function of a monocyte-T cell interaction and probably is mediated through effects on the production/release of eosinophil colony stimulating factor (Eo-CSF).

Antigen-Presenting Cells↗
PubMed1984

Development of calcium and secretory responses in the human promyelocytic leukemia cell line HL60.

We have begun to characterize the development of the excitation-response coupling sequence in the human promyelocytic leukemia cell line HL60. Using the recently developed fluorescent calcium probe quin-2, it was found that DMSO induced myeloid differentiation of the HL60 cells is accompanied by the development of a calcium response to the addition of the chemotactic factors fMet-Leu-Phe and leukotriene B4. The characteristics (time course, concentration dependence, stereospecificity, and metabolic dependence) of the calcium response are extremely similar to those previously described in human neutrophils. These results imply that functional receptors for leukotriene B4 appear in HL60 cells upon the induction of differentiation and also lend strong support to the use of these HL60 cells as a model of human myeloid differentiation. We have also characterized the emergence of a secretory response to fMet-Leu-Phe and leukotriene B4 in cytochalasin B treated HL60 cells. In addition, it is found that differentiation was required for the calcium ionophore A23187 to express its secretory activity toward the HL60 cells. This last set of results implies that differentiation is accompanied by the coordinated appearance of surface receptors and cytoplasmic factors required for the expression of cellular responsiveness.

Aminoquinolines↗
PubMed1984

Survival of granulocytic progenitors in the nonadherent and adherent compartments of human long-term marrow cultures.

We have studied the survival of granulocytic and monocytic progenitor cells (CFU-GM) in human liquid marrow cultures. CFU-GM were present in the nonadherent cell population for a mean of 12 weeks without recharging . Histochemical analysis of agar gels revealed that most day-7 colonies were of neutrophilic type (CFU-N), whereas the majority of day-14 colonies were of mixed neutrophilic-macrophagic type (CFU-NM) for the first four weeks of culture and became predominantly of macrophagic type (CFU-M) thereafter. Eosinophilic colonies (CFU-Eo) declined after week 2 of culture. We have documented that CFU-GM were present in the adherent layer of these cultures, and that the CFU-GM in the nonadherent compartment arise from the adherent layer. In addition, we have compared the pre-CFU-GM survival in the adherent and nonadherent populations and determined that these progenitors were rapidly depleted from both compartments though their survival at the end of week 1 was better in the adherent than in the nonadherent layer.

Bone Marrow Cells↗
PubMed1983

The effect of steroids and filtration leukapheresis on circulating hematopoietic progenitor cells.

Filtration leukapheresis (FL) in which donors are pretreated with steroids, induces a rapid neutropenia followed by neutrophilia. To investigate whether these phenomena are associated with changes in circulating progenitor cells (CFU-GM and BFU-E), 5 donors who underwent FL following steroid administration were compared with a control group who received steroids alone. Steroids alone caused an initial reduction in both circulating lymphocytes and committed progenitor cells followed by a rebound above baseline. Among donors undergoing FL, the changes in lymphocyte counts were identical to the steroid controls and the same early suppression of progenitor cells also occurred, but the rebound was blunted. Thus, the neutrophilia that occurs as a result of the FL procedure is not associated with an increase in circulating progenitor cells; and hence, the procedure does not appear to be a useful adjunct for increasing the yield of hematopoietic stem cells from the peripheral blood.

Female↗
PubMed1982

Secretion of plasminogen activator by the human macrophage-like cell line, GCT: separation from colony-stimulating and erythropoiesis-enhancing activities.

The human macrophage-like cell line, GCT, elaborates monokines such as colony-stimulating activity (CSA) and erythropoiesis-enhancing activity (EEA) which stimulate the growth of primitive blood progenitors in culture. These cells also secrete a fibrinolysis activator (FA), which can be identified if cells are cultured in serum-free medium. FA was found to have a similar molecular weight to CSA and EEA by gel filtration but could be separated from them by ion exchange chromatography. Subcellular fractionation of GCT cells indicated that fibrinolytic activity was present in the cell membranes and cytosol, whereas CSA and EEA were present only in the cytosol. FA resembled urokinase in molecular weight and its strict requirement for plasminogen as a substrate. Double immunodiffusion of GCT activator and urokinase against anti-urokinase antiserum resulted in a line of identity, and incubation of activator with antiserum resulted in loss of its fibrinolytic activity. Thus, GCT activator was similar, if not identical to the plasminogen activator, urokinase.

Cell Line↗
PubMed1981

Autostimulation of growth by human myelogenous leukemia cells (HL-60).

We have studied the effects of medium conditioned by the human progranulocytic leukemia cell line, HL-60, on the subsequent growth of new inocula of HL-60 cells. When HL-60 cells were cultured at high cell density, optimal growth rate occurred in liquid suspension and confluent colony growth was observed in viscous medium without the addition of conditioned medium. However, when cells were cultured at lower cell density, growth rate was reduced and colony growth was nil unless conditioned medium from HL-60 culture was added. All HL-60 populations studied, including the earliest available passage, 9, both elaborated and responded to HL-60 CM. HL-60 CM did not stimulate normal human or mouse granulocyte-monocyte colony-forming cell (CFU-GM) growth. Conditioned media from other human cell lines varied in the ability to stimulate HL-60 cell and CFU-GM proliferation. Some, such as GCT CM, stimulated both HL-60 cells and normal CFU-GM, whereas others, like HL-60 CM, stimulated only HL-60 growth. The majority of cell line CMs tested did not stimulate either HL-60 or CFU-GM. Chromatography of HL-60 CM on Ultrogel AcA54 showed a single peak of HL-60 stimulating activity of apparent molecular weight 13,000. The ability of HL-60 cells to elaborate this activity provides a possible explanation for their proliferation at higher cell densities. Autostimulation may prove to be important in the high growth potential of other cell populations that undergo unrepressed proliferation.

Animals↗
PubMed1981

Hydrophobic adsorption chromatography of colony-stimulating activities and erythroid-enhancing activity from the human monocyte-like cell line, GCT.

The human cell line, GCT, secretes hemopoietins into serum-free culture medium. The conditioned medium contains activities that stimulate neutrophil-monocyte, macrophage, eosinophil, and erythroid colony growth in human marrow cultures. We have used hydrophobic adsorption chromatography to separate a neutrophil-monocyte colony-stimulating factor (CSF) from the other colony-stimulating activities. This hydrophobic CSF has no eosinophil-stimulating activity and is virtually devoid of erythroid-stimulating activity.

Adsorption↗
PubMed1980

Erythropoietic enhancing activity (EEA) secreted by the human cell line, GCT.

Medium conditioned by the monocyte-like cell line GCT contains colony-stimulating activity (CSA), a mediator of in vitro granulopoiesis. Also, the conditioned medium (CM) contains erythroid-enhancing activity (EEA), which can be demonstrated in a system utilizing either nonadherent marrow or blood mononuclear cells, erythropoietin (1-2 units/ml), and 20 ml/dl fetal calf serum. Under these conditions, GCT CM enhances the growth of CFU-E and BFU-E. Attempts were made to characterize the molecular features of EEA. Serum-free GCT cell CM was fractionated on Sephacryl S200 and Ultrogel AcA54. EEA and CSA cochromatographed with apparent molecular weights of approximately 40,000 daltons on Sephacryl and approximately 30,000 daltons on Ultrogel. Fractionation on DEAE Sephacel led to an apparent separation of CSA from EEA; however, when diluted, the fractions containing CSA and EEA. Undiluted fractions containing potent CSA inhibited erythropoiesis; however, dilution of these fractions resulted in marked EEA. Diluted crude GCT CM and DEAE Sephacel fractions enriched in EEA were also capable of sustaining BFU-E in liquid culture and mediating erythropoietin-independent colony growth. CSA could not be unequivocally separated from EEA on concanavalin A-Sepharose, since the diluted void volume containing CSA also had EEA. EEA was present in CM boiled for 60 minutes, whereas CSA was markedly reduced but not abolished. The inverse relationship between CSA concentration and EEA mandates dilution of fractions when bioassayed for these two activities. Although CSA and EEA are similar in molecular weight, they appear to be partially separable by ion-exchange chromatography and heat stability.

Cell Line↗
PubMed1980

The fractionation, characterization, and subcellular localization of colony-stimulating activities released by the human monocyte-like cell line, GCT.

GCT, a human monocyte-like cell line, has been shown to release biochemically distinct colony-stimulating activities (CSAs) for mouse and human marrows. These appear to be periodate-sensitive proteins with critical disulfide bonds. One, of molecular weight 145,000 daltons, stimulates macrophagic colony growth and is related to a 30,000-dalton molecule that also stimulates mouse growth. A 30,000-dalton CSA for human marrow can be separated from the 30,000-dalton mouse CSA by isoelectric focusing and gradient polyacrylamide gel electrophoresis. This distinction agrees with our previous finding of differential neutralization with anti-human urinary CSF antibody. The 30,000-dalton CSAs stimulate neutrophil, neutrophil-monocyte, and eosinophil colony growth in human marrow but only neutrophil and neutrophil-monocyte colonies in the mouse. Subcellular fractionation of GCT cells indicates that there are pools of preformed CSAs primarily associated with the cell cytosol that have similar apparent molecular weights to their secreted counterparts.

Animals↗
PubMed1979

The exceptional responsiveness of certain human myeloid leukemia cells to colony-stimulating activity.

We have studied the marrow cells from a patient with acute myeloid leukemia (AML) for their responsiveness to colony-stimulating activity (CSA) in vitro. The AML cells were stimulated by CSA to rapid and extended growth in liquid culture. In the absence of CSA, the majority of cells died. CSA also stimulated the clonal growth of AML cells, and the minimum requirement for CSA was one-tenth to one-fiftieth that required to stimulate the growth of normal marrow CFU-C. CSA for AML cells was eluted from Sephacryl S-200 columns in fractions that represented an apparent molecular weight of 45,000 daltons. This fraction also produced optimal stimulation of normal human marrow. During remission, the patient's marrow cells did not grow in liquid culture and produced normal numbers of granulocytic and erythroid colonies in response to CSA and erythropoietin. Extended culture of the AML cells resulted in cell differentiation evidenced by decreasing proliferative capacity and by morphological and histochemical changes. These studies indicate that certain AML cells are extraordinarily responsive to CSA, an in vitro mediator of normal granulopoiesis.

Adult↗