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D Olive

Publications and source records attributed to D Olive.

At least 163 records · Page 9Linked to original sources
PubMed1990

Human T cell clones with gamma/delta and alpha/beta receptors are differently stimulated by monoclonal antibodies to CD2.

Requirements for stimulating autocrine proliferation of human T cell clones expressing either alpha/beta or gamma/delta antigen receptors via the "alternative" CD2 pathway have been examined using a large set of monoclonal antibodies (mAb). In the presence of autologous accessory cells (AC, B-lymphoblastoid cell lines) 2 of 13 single CD2 mAb (CLB-T11.1/1 and 6F10.3) stimulated proliferation of gamma/delta but not alpha/beta cells. Interleukin (IL) 1 or IL 6 did not substitute for AC in stimulating gamma/delta clones. Addition of CD28 mAb YTH 913.12 with the CD2 mAb did not result in stimulation of any alpha/beta clones. In the absence of AC, none of the CD2 mAb singly could stimulate any T cell clones, but pairs of mAb directed to different epitopes of CD2 (CLB-T11.1/1 + CLB- T11.2/1 or 6F10.3 + 39C1.5) stimulated both alpha/beta and gamma/delta clones. In both cases, stimulation was reduced by the presence of CD3 mAb. These results confirm that the established AC-independent alternative pathway of T cell activation, which requires binding of two separate epitopes of CD2, operates in both gamma/delta and alpha/beta T cells, and further suggest that an additional pathway initiated by binding of a single CD2 epitope in the presence of AC is exclusively operational in gamma/delta cells.

Antibodies, Monoclonal↗
PubMed1989

Monoclonal antibodies against LFA-1 or its ligand ICAM-1 accelerate CD2 (T11.1 + T11.2)-mediated T cell proliferation.

Activation of human-purified T cells can be mediated by pairwise combinations of monoclonal antibodies directed against T11.1 and T11.2 epitopes on the CD2 molecule. Monoclonal antibodies (mAbs) reactive with either the alpha and beta chains of the lymphocyte-function-associated antigen-1 (LFA-1) molecule or one of its ligands, intercellular adhesion molecule-1 (ICAM-1), were found to accelerate anti-CD2-induced proliferation. This effect was seen on thymocytes and resting or preactivated T cells (phytohemagglutinin blasts and alloproliferative T cell clones) and could be observed, following the introduction of anti-LFA-1 or -ICAM-1 mAbs, up to 50 hr after the CD2 stimulatory signal. This effect was equally abrogated by 55 kDa anti-interleukin-2 (IL-2) receptor mAb, but neither the expression of IL-2 receptor nor the production of IL-2 was modified. The effects of anti-LFA-1 or anti-ICAM-1 on T cell activation through the CD2 pathway were therefore opposite to those observed in the CD3 pathway, where both mAbs strongly delayed T cell proliferation.

Antibodies, Monoclonal↗
PubMed1989

Correlation of CD2 binding and functional properties of multimeric and monomeric lymphocyte function-associated antigen 3.

LFA-3 was purified with an intact (mLFA-3) or an enzymatically removed membrane-anchoring domain (sLFA-3). Gel filtration and sucrose gradient sedimentation showed sLFA-3 to be a single highly glycosylated polypeptide chain in solution, while mLFA-3 formed micelles of 8 LFA-3 monomers. 125I-mLFA-3 bound to Jurkat T leukemic cell surface CD2 with much higher avidity than sLFA-3. mLFA-3 binding had characteristics of a multivalent interaction with cell surface CD2 and had an avidity of 1.5 nM for Jurkat cells and 12 nM for resting T cells. Two CD2 mAbs tested did not block mLFA-3 binding: 9-1 and CD2.1. These mAbs were tested in combination with LFA-3 for their ability to activate T cells. The combination of mLFA-3 and CD2.1 mAbs induced a rapid increase in cytosolic free Ca2+ in Jurkat cells which was proportional to mLFA-3 occupation of CD2 sites. sLFA-3 showed no activity in the Ca2+ flux assay. The combination of mLFA-3 and the CD2.1 mAbs significantly stimulated proliferation of PBMC. The combination of mLFA-3 and 9-1 mAbs was weakly or not mitogenic for the same cells. The combination of CD2.1 and sLFA-3 at concentrations up to 480 nM was not consistently mitogenic. Therefore, monomeric LFA-3/CD2 interaction appears to have a relatively low affinity, while multimeric LFA-3 binds with high avidity. T cell activation by binding of LFA-3 to CD2 appears to require occupation of 10(4) to 10(5) CD2 sites, which is likely to occur during adhesion, but is rare in receptor systems with soluble ligands.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1989

IL-2 receptors on circulating natural killer cells and T lymphocytes. Similarity in number and affinity but difference in transmission of the proliferation signal.

IL-2-binding sites expressed on purified circulating NK cells and high density T lymphocytes were enumerated in 125I-IL-2 binding assays and analyzed by autoradiography after chemical cross-linking of IL-2 to the cells. Quite similar profiles of IL-2R were exhibited by both types of cells consisting of the simultaneous expression of approximately 150 high affinity Tac+ receptors/cell (Kd congruent to 19 pM) and of approximately 540 intermediate affinity Tac- receptors/cell (Kd congruent to 800 pM) which appeared, in cross-linking experiments, to be the isolated 70-kDA protein (p70) subunit of the 55-kDa protein (p55)/p70 heterodimer. The high affinity receptors were distributed on less than 3% of the cells and could be eliminated by complement lysis with anti-p55 mAb. In these conditions, Scatchard analysis no longer revealed two classes of binding sites but only one class of binding sites with intermediate affinity. Although expressed in equal numbers on the surface of NK cells and resting T lymphocytes, the constitutive p70 chains seemed to transmit differently the proliferation signal after effective ligand interaction. Thus, NK cells proliferated strongly in the presence of only 260 pM IL-2, (40 U/ml), whereas resting T cells remained unresponsive to IL-2 concentrations able to saturate the existing p70 receptors (6.5 nM IL-2, 1000 U/ml IL-2) unless monocytes were present. The initiation of cell division seemed to involve the synthesis of p55 chains and the constitution of high affinity receptors as introducing anti-Tac antibody at the start of the cultures inhibited IL-2-induced proliferation. Tac mRNA transcripts accumulated rapidly in NK cells during a 18-h observation period whether anti-Tac antibody was present or not during IL-2 stimulation. In contrast a weak Tac mRNA induction was observed in resting T cells in the same conditions.

Dose-Response Relationship, Immunologic↗
PubMed1989

Analysis of cytosolic ionized calcium variation in polymorphonuclear leukocytes using flow cytometry and Indo-1 AM.

The present report describes the increase in cytosolic-free calcium levels (Ca2+i) induced by chemoattractants in polymorphonuclear leukocytes (PMN) using the new fluorescent Ca2+ chelator Indo-1 AM. Increases in cytosolic Ca2+ were measured by flow cytometry. With this approach, 98% of PMN were found to respond to F-Met-Leu-Phe (FMLP) and leukotriene B4 (LTB4) stimulation. Although both substances induced a rapid and relatively homogeneous rise in Ca2+i, only FMLP gave a sustained Ca2+i rise, whereas that induced by LTB4 appeared transient. In addition, the combined use of wide-angle light scatter and electronic cell volume measurement allowed analysis of Ca2+i variations in the total peripheral blood cell population. The supernatant of a human fibrous histiocytoma cell line (GCT) was able to increase Ca2+ release in PMN. This activity may be ascribed to a new granulocytic activation factor, as neither human recombinant interleukin-1 alpha (IL-1 alpha), granulocyte-colony stimulating factor (G-CSF), nor granulocyte-macrophage-colony stimulating factor (GM-CSF), which were present in this supernatant, were able to induce a Ca2+i rise in PMN.

Calcium↗
PubMed1989

T cell activation via the CD2 molecule is associated with protein kinase C translocation from the cytosol to the plasma membrane.

T cell activation via the CD2 molecule involves phospholipase C and phosphoinositide hydrolysis. Here we demonstrate that the triggering of subclones of the human T leukemia Jurkat cell line by anti-CD2 as well as anti-CD3 monoclonal antibodies is able to induce activation (i.e. translocation from cytosol to cell membrane) of protein kinase C (PKC), which is dependent on the formation of 1,2-diacylglycerol from inositol 4-5-bisphosphate. The kinetics of PKC translocation parallels the rise in intracellular calcium following both CD2 and CD3 stimulations. These results further demonstrate that CD2 and CD3 activation pathways use similar signal transduction mechanisms.

Antibodies, Monoclonal↗
PubMed1989

Cholera toxin inhibits the increase in cytoplasmic free calcium induced via the CD2 pathway of human T-lymphocyte activation.

We investigated the action of cholera toxin on the intracellular ionized calcium [Ca2+]i increase induced by anti-CD2 and anti-CD3 monoclonal antibodies in the leukemic human T-cell line Jurkat. Cholera toxin inhibits in a dose-dependent manner these two pathways of human T-lymphocyte activation but with different half maximal inhibition doses (75 ng/ml for CD3, 30 ng/ml for CD2). This effect cannot be accounted for only by the increase in cAMP induced by cholera toxin because forskolin, which raises cellular cyclic adenosine monophosphate (cAMP) to the same levels, induced only a small inhibition of the [Ca2+]i increase in similar conditions. Cholera toxin induced a decrease in the surface expression of the CD3 molecule, suggesting a down-regulation of the CD3 molecules. On the other hand, the expression of CD2 remained unchanged. Cell surface disappearance of the CD3 molecule cannot account for all the inhibitory effects of cholera toxin because CD2 molecule expression was not affected (no modifications in the half maximal binding of anti-CD2 monoclonal antibodies). All together, these results suggest that cholera toxin acts on substrates, possibly G proteins, that could regulate the [Ca2+]i increase induced by anti-CD2 and anti-CD3 mAbs in Jurkat cells. In addition, the present study demonstrated that the rise in cellular cAMP partially inhibits the [Ca2+]i increase induced by anti-CD2 and anti-CD3 mAbs.

Antibodies, Monoclonal↗
PubMed1989

Initial chemotherapy including ifosfamide in the management of Ewing's sarcoma: preliminary results. A protocol of the French Pediatric Oncology Society (SFOP).

Phase II studies using ifosfamide both alone and combined with vindesine and cisplatin have shown the effectiveness of this drug in patients with Ewing's sarcoma (ES) who had relapsed during VAC (vincristine, actinomycin, cyclosphosphamide)/VAd (vincristine, Adriamycin) therapy. In November 1984, these results led the SFOP to adopt a protocol consisting of (1) initial chemotherapy with three cycles of IVA (ifosfamide, 3 g/m2 on days 1 and 2; actinomycin D, 750 mg/m2 on days 1-3; vincristine, 1.5 mg/m2 on day 1) alternating every 3 weeks with IVAd (vincristine on day 22; ifosfamide on days 21-23; Adriamycin, 60 mg/m2 on day 22); (2) radical surgery if possible; (3) local radiotherapy (RT); and (4) maintenance chemotherapy with alternating IVA and VAd (vincristine, Adriamycin) for up to 9 months. In May 1987, 87 patients with previously untreated ES entered the study; 61 had localized ES. To date, 54 patients with localized disease and 22 with metastatic disease have finished initial chemotherapy; 40 patients with localized disease have been evaluated. In all, 28 patients (70%) were in complete remission (17 patients) or had a tumor regression of greater than 50% 11 patients) and were considered to be good responders; 12 patients were considered to be poor responders. After local radiotherapy in all but 7 patients and surgical resection in 29, 52 of 54 were considered to be in clinical remission. A total of 13 patients with metastatic disease were good responders at the completion of the initial chemotherapy. These results confirm the efficacy of primary chemotherapy using ifosfamide for the treatment of ES.

Adolescent↗
PubMed1989

Estrogen induces the development of autoantibodies and promotes salivary gland lymphoid infiltrates in normal mice.

There are important bidirectional interactions between the immune and the endocrine system. Sex hormones influence the immune system throughout life including postnatal and prenatal stages. For example, we find that administration of estrogen to normal mice markedly augments the ability of CD5+ B cells to express their autoimmune potential by producing increased numbers of plaque-forming cells (APFC) to bromelain-treated mouse erythrocytes (Br-ME). The effect of sex hormones on immune function at the most critical stage of development, the prenatal period, remains unstudied. We hypothesize that an imbalance of the in utero sex hormone microenvironment critically influences the fetal immune system. We have termed this influence immunological imprinting. After birth this imprinting could contribute to immune-mediated disorders. To test this hypothesis, we developed a mouse model in which normal mice were prenatally exposed to estrogens. In preliminary experiments, these mice produced higher numbers of APFC to Br-ME, particularly in the peritoneal cavity cell exudates. Furthermore, mice prenatally exposed to estrogens had accelerated development of autoimmune salivary gland lesions indistinguishable from Sjögren's syndrome (SS) in humans. Further experiments are warranted to confirm these findings. The prenatal effects of estrogen may have relevance for familial and neonatal autoimmune syndromes.

Animals↗
PubMed1989

Pilot phase I study using zidovudine in association with a 10-day course of anti-CD4 monoclonal antibody in seven AIDS patients.

Experimental evidence has demonstrated that monoclonal antibody (MAb) 13B8.2, a workshop-qualified anti-CD4 MAb, (1) inhibits in vitro syncytium formation as well as in vitro HIV infection of CD4+ T cells; (2) delivers negative signals to T cells, thus preventing T-cell activation and viral replication; (3) contributes to CD4+ T-cell clearance by its Fc portion, and (4) induces an immune response by the patient, contributing potentially to an anti-idiotypic response of interest for the control of the immune parameters of the disease. On this basis a phase I study combining zidovudine treatment and a 10-day course of anti-CD4 MAb was performed in seven AIDS patients (Centers for Disease Control group IV). The treatment was well tolerated. MAb dosage and schedule were adjusted on the basis of circulating CD4+ cells and MAb pharmacokinetics; immunological and virological parameters were also monitored. One patient presented a transient increment in CD4+ T cells associated with augmented T-cell function, the suppression of p24 in the serum and a negative RT assay. A second patient had a steady increment of CD4+ T cells after completion of the treatment, with a transient decrease of serum p24 5 days after completion of the anti-CD4 protocol.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Human B cell activating factor (BCAF): production by a human T cell tumor line.

In a previous study, we demonstrated that supernatants from human T cell clones stimulated by a pair of anti-CD2 monoclonal antibodies cause resting human B cells to become activated and to proliferate in the absence of any other signals. The activity responsible for these effects was shown to be different from already characterized lymphokines and in particular from IL-2 and IL-4, and was named B Cell Activating Factor or BCAF. In this paper, we describe the production of BCAF by a human T cell tumor line T687 after phorbol myristate acetate (PMA) stimulation; this production can be potentiated by phytohemagglutinin (PHA). We further show that the stimulatory phase can be separated from the secretory phase thereby avoiding contamination of BCAF-containing supernatant by PMA and PHA. Supernatants produced under these conditions do not contain either IL-4 or IFN but contain traces of lymphotoxin and 2 to 10 ng/ml of IL-2. The T687 cell line will allow us to obtain a large volume of supernatant for biochemical study and purification of the molecule(s) responsible for BCAF activity.

B-Lymphocytes↗
PubMed1989

Anti LFA1 monoclonal antibody for the prevention of graft rejection after T cell-depleted HLA-matched bone marrow transplantation for leukemia in adults.

A mouse IgG monoclonal antibody (MoAb) directed against the human LFA1 molecule (25.3 MoAb) was used in nine adult leukemic patients to prevent graft rejection after T cell-depleted HLA matched bone marrow transplantation. Based on the results of a previous study in children 0.1 mg/kg of 25.3 was given on days -3, -1, +1, +3, +5 in addition to a standard conditioning regimen with cyclophosphamide (120 mg/kg) and fractionated total body irradiation. The marrow transplant was T cell-depleted using T101 Fab immunotoxin ricin A chain. Seven patients received post-graft immunosuppression with methotrexate and cyclosporine A; two patients received no immunosuppression post-graft. A mean T cell depletion of 98.3% (80-100%) was achieved. Tolerance to the infusions of 25.3 MoAb was excellent. No patient developed any form of graft-versus-host disease. However two patients failed to engraft and three patients had delayed graft failures. These results show that this regimen of anti LFA1 MoAb, which was extremely good at permitting engraftment of HLA mismatched T cell-depleted transplant in children with constitutional diseases, is not able to prevent graft failure and rejection of T cell-depleted HLA matched transplants in adults with leukemia. Further efforts are needed to overcome graft failures in this clinical situation.

Adult↗
PubMed1988

The CD2 ligand LFA-3 activates T cells but depends on the expression and function of the antigen receptor.

The T cell Ag receptor (CD3/Ti) and the sheep E receptor (CD2) expressed on the surface of human T cells are both capable of initiating intracellular signals necessary for T cell activation. CD3/Ti interacts with Ag to initiate cellular immune responses. Although the exact function of CD2 is unknown, lymphocyte function-associated Ag 3 (LFA-3), a 55- to 70-kDa receptor expressed on a broad spectrum of hemopoietic and nonhemopoietic cells, has recently been shown to be its natural ligand. We show here that although purified multimeric LFA-3 is not capable of initiating transmembrane signaling events on its own, the combination of LFA-3 and the anti-CD2 mAb CD2.1 induces intracellular calcium increases, phosphatidylinositol second messenger generation and lymphokine secretion in the T cell leukemic line Jurkat. In order to study the signaling requirements of CD2, we compared the ability of CD2 mAb and LFA-3 to initiate activation signals in Jurkat and in three Jurkat-derived mutants. A CD3-CD2+ mutant failed to increase calcium or exhibit phosphatidylinositol hydrolysis to either the combination of agonist CD2 mAb 9-1 and 9.6 or LFA-3 and CD2.1. Reconstitution of the Ag receptor by transfection of the Ti-beta-chain restored the expression of the CD3/Ti complex and the ability to respond to either combination of CD2 ligands. However, no response to CD2 ligands was detected in a CD3+CD2+ mutant selected for signaling defects to CD3/Ti ligands. Complementation of the CD3/Ti signaling defect by cell fusion also restored competency to respond to CD2 agonists. These results demonstrate that LFA-3 under appropriate conditions can activate T cells via the CD2 complex and that this activation requires not only the cell surface expression of the CD3/Ti complex but also a functional Ag receptor pathway.

Adjuvants, Immunologic↗
PubMed1988

Role of the LFA3-CD2 interaction in human specific B cell differentiation.

We examined the role of the lymphocyte function-associated (LFA)3 molecule in human B cell response. A mAb to this molecule did not influence B cell proliferation induced by anti-mu antibody and IL. In contrast, the same mAb inhibited the specific T-dependent B cell response induced by a particulate Ag. In the same line, two anti-CD2 mAb (directed toward the T11-1 and T11-2 epitopes) inhibited this response, whether used alone or in association. These inhibitions took place at an early stage of the response, and anti-LFA3 and anti-CD2 mAb acted on B cells and T cells, respectively. In contrast, when T cell help was provided by exogenous IL-2, the B cell response was resistant to the inhibitory effect of anti-LFA3 mAb. Taken together, these results indicate that the LFA3-CD2 pair play a major role in the direct T-B interaction required for T cell help.

Animals↗
PubMed1988

Synergistic activation of human T cells by interleukin 1 and interleukin 6.

Purified human interleukin 6 (IL 6) was found to stimulate the proliferation of human tonsillar and peripheral rosetting T cells subliminally activated with phytohemagglutinin (PHA). This response seemed independent of IL 2 but highly dependent on the presence of accessory cells. Indeed, when accessory cell-depleted tonsillar T cells were activated with PHA and exposed to IL 6, only minimal proliferations were observed. A similar result was obtained with IL 1. However, a combination of these two cytokines induced strong proliferations, indicating that IL 1 and IL 6 plays a synergistic role in the interactions between accessory cells and T lymphocytes.

Antigen-Presenting Cells↗