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Biomedical subjects

G Trinchieri

Publications and source records attributed to G Trinchieri.

At least 235 records · Page 13Linked to original sources
PubMed1983

Immune interferon induces the receptor for monomeric IgG1 on human monocytic and myeloid cells.

We report here that FcR for human monomeric IgG1 can be induced on cells of myeloid origin cultured in the presence of IFN gamma for 8 h. Supernatant fluids from cultures of lymphocytes infected with a variety of viruses or cocultured with cell lines have the same FcR enhancing effect as IFN gamma. We identify the factor in the supernatant fluid responsible for the induction as immune interferon. Among the different types of IFN, only the gamma type (both purified and recombinant) specifically induces the appearance of FcR for monomeric IgG1 on normal and leukemic myeloid cells but not on cells of lymphoid origin. This effect is also evident on mature PMN. We show that the specificity and the affinity of the receptor induced on HL-60 promyelocytic cells, peripheral blood monocytes, and PMN are identical to those of the receptor spontaneously present on the same cells, except for PMN, which do not spontaneously express this type of receptor. The results of inhibition experiments performed with mouse IgG of and IgG3. These results suggest that the receptor present on human monocytes different isotypes indicate that the receptor can be inhibited by murine IgG2a or immature myeloid cells, selectively inducible by IFN gamma, has a specificity similar to the FcR1 described on mouse macrophages.

Bone Marrow Cells↗
PubMed1983

Membrane proteins on human megakaryocytes and platelets identified by monoclonal antibodies.

We describe five monoclonal antibodies that react with four discrete antigens present on human platelets. Antibodies B2.12 and B59.2 precipitate the glycoprotein IIb-IIIa complex from radiolabeled platelet membrane extracts and inhibit platelet aggregation induced by adenosine diphosphate (ADP), collagen, or epinephrine. The antigen recognized by the two antibodies is present on megakaryocytes but either absent entirely or expressed in small amounts on platelets from Glanzmann's thrombasthenic patients. The antigen recognized by antibody B37.3 is absent from thrombasthenic platelets. Antibody B1.12 reacts with an antigen shared by platelets and 20% of peripheral blood lymphocytes and is a potent inducer of platelet aggregation. Antibody B2.10 reacts specifically with platelets and megakaryocytes but does not affect platelet functions. Thus, these reagents are useful tools in diagnostic and functional studies of both normal and abnormal platelets.

Antibodies, Monoclonal↗
PubMed1983

Characterization by monoclonal antibodies of the cytotoxic effector cells in human peripheral blood mononuclear cells reactive against anchorage-dependent tumour cell lines.

The effector cells for spontaneous cytotoxicity against anchorage-dependent human or mouse tumour cell lines in a 72-h iododeoxyuridine-release assay by normal human peripheral blood cells (PBMNC) or monocyte-enriched fractions were analysed by the use of monoclonal antibodies. PBMNC or adherent or elutriated monocyte-enriched populations of PBMNC were depleted of monoclonal antibody-reactive cells by complement-dependent lysis or separated into monoclonal-antibody-positive or -negative subsets by an indirect rosetting technique followed by Ficoll-Hypaque density gradient separation. The experimental data indicated that in both PBMNC and monocyte-enriched populations, an appreciable proportion of the effector cells with cytolytic activity against adherent human or mouse tumour target cells were positive with B73.1.1 (an antibody with a high degree of selectivity for natural killer (NK) cells), B43.4.1 (or OKM1), and with OKT11a (an antibody recognizing the receptors for sheep erythrocytes), and had the morphology of large granular cells, which have previously been shown to mediate NK activity. These effector cells were mostly negative for BRL.1, BRL.2, B52.1.1, B44.1.1, B13.4.1 and DR antigens, unlike classical monocytes. Some cells which are cytotoxic for the adherent mouse, SV-40-transformed kidney tumour line, TU-5, may bear B52.1.1 or other monocyte-like antigens. Taken together, these results indicate that, in monocyte-enriched populations, both NK cells and monocytes have cytotoxic effector activity against various human and mouse adherent target cell lines.

Animals↗
PubMed1983

Correlation between differentiation, expression of monocyte-specific antigens, and cytotoxic functions in human promyelocytic cell lines treated with leukocyte-conditioned medium.

Human promyelocytic cells lines treated with conditioned medium from PHA-stimulated leukocytes acquire several phenotypic and functional markers of differentiated monocytes. In this paper, we demonstrate that promyelocytic cells treated with conditioned medium express, among other markers, monocyte-specific and HLA-DR antigens absent from the parental cells and become potent effectors of antibody-dependent cell-mediated cytotoxicity against erythrocytes and tumor cells. In cultures of promyelocytic cell lines maintained in the presence of conditioned medium, an equilibrium between proliferation and differentiation is established, and two cell populations can be separated on the basis of expression of differentiation surface markers. One population has a differentiated morphology, expresses nonspecific esterase activity, Fc receptors, C receptors, monocyte-specific and HLA-DR antigens, is able to mediate antibody-dependent cytotoxicity, and has a limited ability to proliferate. A second population retains the phenotype of undifferentiated promyelocytes and continues to proliferate. The differentiated monocyte-like cells originate from a proportion of the proliferating promyelocytes that respond to the differentiation inducers contained in the conditioned medium.

Antigens, Surface↗
PubMed1983

Exposure of platelet fibrinogen-binding sites by collagen, arachidonic acid, and ADP: inhibition by a monoclonal antibody to the glycoprotein IIb-IIIa complex.

Following stimulation with adenosine diphosphate (ADP), collagen, or arachidonic acid, unstirred human platelet suspensions bind 125I-fibrinogen in a reaction that reaches completion within 30 min. Scatchard analysis of these binding data reveals two sets of binding sites with all 3 agents: a high affinity site (Kd 0.029-0.045 microM) binding 1000-1600 fibrinogen molecules per platelet, and a lower affinity site (Kd 1.2-2.0 microM) binding 46,000-76,000 fibrinogen molecules per platelet. At a concentration of apyrase that inhibited ADP-induced fibrinogen binding by greater than 85%, fibrinogen binding induced by collagen and arachidonic acid was only partially affected. This suggests that fibrinogen binding induced by collagen or arachidonic acid does not require released ADP. We isolated a monoclonal antibody, B59.2, which precipitated the glycoprotein IIb-IIIa complex from solubilized platelet membranes. Binding of labeled antibody to platelets before or after exposure to ADP, collagen, or arachidonic acid showed a single class of approximately 22,000 binding sites with Kd 0.019 microM. Binding of B59.2 was complete within 1 min and was not inhibited by EDTA. Preincubation of platelet suspensions with a 2.1 microM concentration of B59.2 caused inhibition of secretion and aggregation, but not of thromboxane-B2 synthesis, in response to 1 microgram/ml collagen, 40 microM arachidonic acid, or 4 microM ADP, concentrations of aggregating agents that produced complete aggregation and secretion in the absence of B59.2. At this concentration of B59.2, fibrinogen binding to stimulated platelets was inhibited by approximately 45%-55%. These data demonstrate that collagen and arachidonic acid can expose fibrinogen binding sites independently of released ADP; and that the glycoprotein IIb-IIIa complex is involved in secretion, aggregation, and fibrinogen binding, but not in thromboxane synthesis occurring in response to collagen, arachidonic acid, or ADP.

Adenosine Diphosphate↗
PubMed1983

Human natural killer cells analyzed by B73.1, a monoclonal antibody blocking Fc receptor functions. II. Studies of B73.1 antibody-antigen interaction on the lymphocyte membrane.

In this paper, we characterize the antigen recognized by the monoclonal antibody B73.1 and the modification occurring at the membrane of the positive cells after interaction with the antibody. The B73.1-defined antigen is a protein of 50,000 to 72,000 daltons that is sensitive to pronase but not to trypsin treatment. B73.1 antibody, and its F(ab')2 fragment, directly block, at high concentrations, the binding of IgG antibody-sensitized erythrocytes to the Fc receptors (FcR) of a subpopulation of lymphocytes and neutrophils. B73.1 antibody dissociates rapidly from the positive cells, but concomitant modulation of both B73.1 antigen and FcR is induced when cells are incubated in the continuous presence of antibody or when B73.1 antibody is cross-linked at the cell membrane with an anti-mouse immunoglobulin antiserum. Reaction of lymphocytes with immune complexes also induces modulation of both FcR and B73.1 antigen, without affecting the expression of other antigens on the positive cells. The possibility that the antigen is internalized and digested by the cell after reaction with the antibody is discussed. B73.1 antibody inhibits antibody-dependent cytotoxicity mediated by lymphocytes (K cells) and neutrophils, whereas it does not affect spontaneous cytotoxicity of NK cells. These results suggest the B73.1-defined antigen might be the FcR or a structure closely related to it on K/NK cells.

Antibodies, Monoclonal↗
PubMed1983

A human NK and K cell subset shares with cytotoxic T cells expression of the antigen recognized by antibody OKT8.

The antigen recognized by monoclonal antibody OKT8 is expressed on the cell membrane of 30 to 50% of human NK/K cells. The reactivity of OKT8 with NK/K cells was determined by indirect methods (treatment of the effector cells with OKT8 antibody and complement (C) and separation of OKT8(+) and (-) effector cell populations by fluorescence-activated cell sorting or by rosetting techniques) and, at single cell level, by C-dependent lysis of effector NK cells that bind and kill K562 targets. Analysis by indirect immunofluorescence (flow cytofluorometry) of lymphocyte subpopulations mediating NK/K cytotoxic activity and deprived of OKT8(+) T cells reveals that the NK/K cell subset bears OKT8 antigen at a density lower than that present on cytotoxic T cells. The OKT8 antigen on NK/K cells is trypsin- and pronase-sensitive, but it is resynthesized by the same effector cells during 24 hr of culture at 37 degrees C. OKT8 antibody does not inhibit NK killing, and, on a per cell basis, OKT8(+) cells within the NK/K subset mediate the same level of cytotoxic activity as OKT8(-) NK/K cells. Analogous results were obtained by using anti-Leu-2a, an antibody with the same specificity as OKT8 on cytotoxic/suppressor T cells, but not when OKT5 was used, which might identify a distinct epitope on the same antigenic molecule. The possible significance of these findings in understanding the cell lineage of NK/K cells is discussed.

Animals↗
PubMed1983

Human natural killer cells analyzed by B73.1, a monoclonal antibody blocking Fc receptor functions. I. Characterization of the lymphocyte subset reactive with B73.1.

We describe the production of the monoclonal antibody B73.1, reacting with a subset of human lymphocytes and, in about one-half of the donors, with neutrophilic polymorphonuclear leukocytes. In the peripheral blood from normal adult donors, 14.6 +/- 8.5% of the lymphocytes react with B73.1 antibody. The B73.1(+) lymphocyte subset does not bear markers of typical T or B cells and corresponds to the lymphocyte subset containing antibody-dependent killer (K) and natural killer (NK) cells. We demonstrate that: a) virtually all lymphocytes with K/NK cytotoxic activity are found in the lymphocyte subpopulation bearing the B73.1-defined antigen; b) the B73.1(+) lymphocyte subset bears the combination of antigens known to be present on K/NK cells; and c) there is a positive correlation between the level of cytotoxicity and the actual number of B73.1(+) lymphocytes in individual donors. We also report the distribution of B73.1(+) lymphocytes according to donor age and tissue types. The use of the B73.1 antibody in quantitating the actual number of K/NK cells and in performing functional studies on spontaneous cytotoxicity is discussed.

Adolescent↗
PubMed1982

Binding of platelets to human monocytes: a source of artifacts in the study of the specificity of antileukocyte antibodies.

A serious and often ignored source of artifacts when testing the specificity of antibodies is the contamination of leukocyte preparations with platelets which subsequently adhere to monocytes. The presence of Ca2+ chelating agents or acetylsalicylic acid in the washing buffers inhibits adhesion of platelets to monocytes, thus permitting an accurate distinction among antibodies that are specific for monocytes, platelets or both. The analysis of the specificity of various new or recently described monoclonal antibodies reactive with these cell types is reported here.

Antibodies, Monoclonal↗
PubMed1982

Monoclonal antibodies that detect differentiation surface antigens on human myelomonocytic cells.

We describe here the production and characterization of several new monoclonal antibodies that recognize differentiation antigens present on human cells of the myelomonocytic lineage. The lineage and the stage specificities of our reagents (myeloid-, monocytic-, and myelomonocytic-specific) were determined on the basis of their reactivity with human cell lines and with human peripheral blood and bone marrow cells. Cross-competition experiments demonstrated that some of the antibodies react with the same or closely associated antigenic determinants. Five antigens have been identified in this way: one present on myeloid, one on monocytic, and three on both myeloid and monocytic cells. The possible relationship of our antibodies with other established monoclonal antibodies is discussed, in addition to their use in the in vitro study of the differentiation pathways of human hemopoietic cells and in the characterization of leukemias.

Animals↗
PubMed1981

Cytotoxic activity and interferon production by lymphocytes from patients with multiple sclerosis.

Peripheral blood lymphocytes from MS patients and from healthy control donors were compared for their ability to mediate spontaneous and antibody-dependent cell-mediated cytotoxicity. They were also compared for their ability to respond to infection with various strains of measles and sSPE viruses with interferon production and enhanced NK activity. Neither SLMC nor ADCC against several different target cells was found to be impaired in the MS population. Furthermore, no defect was detected in the response of patients' lymphocytes to virus challenge in vitro in terms of both activation of NK cells and interferon production. Enhanced NK activity was also induced by an exogenous interferon preparation and by Poly I:C to the same extent in patients and controls.

Adult↗
PubMed1981

Antagonistic effects of interferons on the cytotoxicity mediated by natural killer cells.

Human interferons (IFs) can induce a several-fold increase in the natural cytotoxicity of human lymphocytes on target cell lines. IFs increase the efficiency of cytotoxicity and the number of natural killer (NK) cells. In mixed cultures of lymphocytes and other tumor-derived or virus-infected cells, endogenous IF is produced, which mediates 70-90% of the observed cytotoxicity. The effect of IF on target cells is antagonistic to its effect on lymphocytes: the susceptibility to lysis of cells treated with IF decreases. Whereas normal fibroblasts are protected by IF, virus-infected cells and most tumor-derived cells are not. The protective effect is specific for NK cells cytotoxicity: IF-treated target cells are lysed to the same extent as the untreated controls by antibody-dependent killer cells, by phytohemagglutinin-stimulated lymphocytes, by cytotoxic T lymphocytes, and by antibodies and complement. NK cells bind to IF-treated fibroblasts, but are unable to lyse them. The cytotoxic ability of NK cells is inactivated after interaction with normal fibroblasts, but not with IF-treated fibroblasts. Unlabeled, normal fibroblasts but not IF-treated fibroblasts compete for the cytotoxicity mediated by NK cells in 51Cr-labeled target fibroblasts. IF, by stimulating very efficient, nonspecific cytotoxic cells, and by protecting normal cells from lysis, might render the NK cell system an inducible defense mechanism against virus-infected and tumor cells.

Cell Line↗
PubMed1981

Terminal differentiation surface antigens of myelomonocytic cells are expressed in human promyelocytic leukemia cells (HL60) treated with chemical inducers.

The expression of two surface antigens present on the cell membrane of both human granulocytes and monocytes was studied during the process of myelomonocytic differentiation using two monoclonal antibodies (B9.8.1 and B13.4.1). These surface antigens are not present on immature myeloid cells nor on nonmyeloid hematopoietic cells, but can be detected when the cells are terminally differentiated. Among the bone marrow cells, B13.4.1 binds to metamyelocytes and B9.8.1 to metamyelocytes and a fraction (30%) of myelocytes. HL60 human promyelocytic leukemia cells did not react with such monoclonal antibodies. However, when such cells were induced to differentiate in vitro into mature myeloid elements by treatment with retinoic acid or dimethyl sulfoxide, 70%--90% of the differentiated cells expressed both surface antigens. Cell sorting studies on these treated HL60 cells indicated that myelocytes and metamyelocytes were the most immature cells expressing such markers. Expression of the two surface antigens was also observed when HL60 cells were induced to differentiate into monocyte/macrophage cells by treatment with the tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate. Thus, human promyelocytic leukemia cells induced to differentiate in vitro by treatment with specific chemical agents express membrane antigens in the same pattern as normal bone marrow myeloid cells at the corresponding stage of differentiation.

Animals↗
PubMed1981

Interferon-induced resistance of fibroblasts to cytolysis mediated by natural killer cells: specificity and mechanism.

Interferons (IF) have been shown to have a complex regulatory effect on cell-mediated cytotoxicity. In this paper, we described our analysis of the protective effect of IF on human fibroblast target cells. Fibroblasts that have been preincubated with IF are not lysed by natural killer (NK) cells. This IF-induced protection is not observed in antibody-dependent cell-mediated cytotoxicity nor in complement-dependent lysis. Both types of leukocyte IF, viral and immune, and fibroblast IF protect fibroblasts from NK cell-mediated lysis. Electrophoretically purified viral type leukocyte IF also induces protection. Experiments of absorption of NK cells on target cell monolayers and analysis of cytotoxicity at the single-cell level in semisolid medium demonstrate that NK cells bind to both IF-treated and untreated fibroblasts but lyse only the latter. The cytotoxic ability of NK cells is inactivated after interaction with fibroblasts but not with IF-treated fibroblasts. Unlabeled normal fibroblasts, but not IF-treated fibroblasts, compete for the cytotoxicity mediated by NK cells on 51Cr-labeled target fibroblasts. Based on these findings, we propose a possible interpretation of the paradoxic existence of cells that can kill normal cells in the organism and still function in cell-mediated immunity to protect against virus-infected or tumor cells.

Absorption↗
PubMed1981

Inactivation of natural killer cell cytotoxic activity after interaction with target cells.

Human peripheral blood lymphocytes were cultured with unlabeled target cells or absorbed to K562 cells and then isolated by centrifugation on discontinuous Ficoll-Methrizoate gradient. In both cases, lymphocytes that reacted with these target cells at 37 degrees C were inactivated and were no longer able to kill freshly added 51Cr-labeled target cells that were susceptible to spontaneous killing. This inactivation was time and temperature dependent and did not alter the ability of lymphocytes to lyse antibody-sensitized target cells. The natural killer (NK) cell inactivation that followed the interaction with target cells was not observed when target cells were used that were able to induce interferon (IFN) production when cultured with lymphocytes. This NK inactivation was reversed by incubation of the inactivated effector cell preparations with IFN.

Animals↗
PubMed1980

Monoclonal antibodies specific for kappa chain, lambda chain, and IgG1 of human gammaglobulin.

Hybrid cell lines secreting antibodies specific for human gammaglobulin (HGG) were prepared by cell fusion and cloning techniques. The monoclonal antibodies were tested for their antibody reacts with a different antigenic determinant of HGG. One reacts with isolated kappa (kappa) light chains, one with isolated lambda (lambda) light chains, and one with the Fc fragment of IgG1 molecules. The reactivity patterns of two additional monoclonal antibodies are more complex. One reacts with a determinant present on the Fc of all IgG subclasses and the other binds to a determinant on the Fab of IgG molecules. The two monoclonal antibodies reactive with light chains also bind to surface components of human B cells. The murine immunoglobulin (Ig) class of each clone product was identified.

Animals↗
PubMed1980

Interferon production by human and murine lymphocytes in response to alloantigens.

The production of interferon (IF) by human and mouse lymphocytes sensitized to alloantigens in mixed lymphocyte cultures (MLC) was analyzed. During primary MLC, IF appeared in the culture fluid on day 2 and was maximal on day 5. Based on several biologic criteria, the IF produced is of the "immune" type. When lymphocytes sensitized to alloantigens were reestimulated in vitro, IF was produced within a few hours of culture. In all stimulated cultures, cell proliferation was observed in spite of the high concentrations of IF. The IF-producing cells in human MLC were identified as T lymphocytes lacking the receptor for the Fc fragment of IgG molecules (Fc gamma R(-)). Human MLC supernatants containing immune type IF mediate the enhancement of natural killer (NK) cell activity and protect NK target cells from lysis.

Animals↗