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G Trinchieri

Publications and source records attributed to G Trinchieri.

At least 217 records · Page 12Linked to original sources
PubMed1986

Tumor necrosis factor and lymphotoxin induce differentiation of human myeloid cell lines in synergy with immune interferon.

We show that the cytotoxins tumor necrosis factor (TNF) or lymphotoxin (LT), at concentrations of approximately 10(-11) M induce monocytic differentiation of human myeloid cell lines. After 5 d of culture in the presence of rTNF and LT, a significant proportion of the myeloid cell lines express monocyte differentiation antigens and ANAE activity, and become able to reduce nitroblue tetrazolium (NBT) and mediate low levels of ADCC against tumor target cells. These markers of differentiation, however, are maximally induced when rIFN-gamma, at concentrations as low as 4 U/ml, is present simultaneously with the cytotoxins, and the two classes of cytokines act synergistically to induce terminal differentiation. The appearance of monocytic antigens is accompanied by acquisition of morphology and other functional properties of mature monocytic cells, such as chemiluminescence and phagocytosis, and by expression of FcR for monomeric IgG. A decrease in cell proliferation accompanies induced differentiation, and is not due to the cytotoxic properties of TNF or LT, as indicated in simultaneous analysis of surface phenotype and cell cycle. The lack of cytotoxicity of TNF on the HL-60 cell line is also demonstrated by the enhancing effect of TNF on HL-60 cell growth and nucleoside uptake in the first 2 d of culture. These data show that the cytotoxins TNF and LT mediate complex effects on cells of the myelomonocytic lineage and, in synergy with IFN-gamma, can fully induce immature myeloid cells to differentiate into cells with phenotypic, functional, and proliferative characteristics of terminally differentiated myelomonocytic cells.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1986

Requirement for HLA-DR+ accessory cells in natural killing of cytomegalovirus-infected fibroblasts.

The role of HLA-DR+ cells in NK activity against CMV-infected FS4 foreskin fibroblasts and K562 erythroleukemia cells was examined. When nonadherent PBMC were depleted of either HLA-DR+ or Leu-11b+ cells by treatment with mAbs plus C, NK activity against CMV-FS4 target cells was markedly reduced. In contrast, depletion of HLA-DR+ cells had no effect on NK activity against K562 target cells. When HLA-DR-depleted cells were added to Leu-11b-depleted cells, NK activity against CMV-FS4 was restored. Negative selection experiments indicated that the HLA-DR+ cells contributing to NK activity against CMV-FS4 are not B or T cells, while negative and positive selection experiments excluded a role for monocytes. Experiments in which HLA-DR- and Leu-11b- cells were mixed in varying proportions indicated that NK(CMV-FS4) is mediated by Leu-11b+ cells, while HLA-DR+ cells provide an accessory function. Irradiation (50 GY) abolished the NK effector function of Leu-11b+ cells, but not the accessory function of HLA-DR+ cells. The NK activity against CMV-FS4 of HLA-DR- cells was restored by the addition of rIFN-alpha or of cell-free supernatants generated by coculturing PBMC or Leu-11b- cells with CMV-FS4. The ability of these supernatants to restore NK activity of HLA-DR- cells was completely abrogated by the addition of neutralizing amounts of antibody to IFN-alpha. In related experiments, neutralization of IFN-alpha in NK assays had little or no effect on NK activity against CMV-FS4, suggesting that the accessory function of HLA-DR+ cells might be mediated by alternative mechanisms in addition to the secretion of extracellular IFN-alpha.

Antigen-Presenting Cells↗
PubMed1986

Gamma interferon and lymphotoxin, released by activated T cells, synergize to inhibit granulocyte/monocyte colony formation.

We have shown that lymphocytes stimulated by PHA produce colony-forming unit of granulocyte/monocyte (CFU-GM)-stimulating and -inhibiting activities, IFN-gamma, and lymphotoxin (LT). IFN-gamma is necessary for inhibition of CFU-GM by PHA-conditioned medium (CM), as shown by experiments in which removal of IFN-gamma from PHA-CM abrogated inhibition. However, experiments in which rIFN-gamma was added to IFN-gamma-depleted PHA-CM revealed the presence, in PHA-CM, of other factors that act in synergy with IFN-gamma to inhibit CFU-GM. Fractionation of PHA-CM on a Sephadex G-100 column was used to separate IFN-gamma and LT. Colony-inhibiting activity was eluted in fractions that contained both IFN-gamma and LT activities, identifying LT as a factor present in PHA-CM that synergizes with IFN-gamma to inhibit CFU-GM. Treatment of PHA-CM with mAb against either IFN-gamma or LT completely abrogated the colony-inhibiting activity, demonstrating a requirement for both lymphokines in PHA-CM-induced inhibition of CFU-GM. Experiments using rIFN-gamma and preparations of purified LT confirmed that neither lymphokine alone, when added to bone marrow cells at the concentrations present in PHA-CM, strongly inhibited day 7 or day 14 CFU-GM, but that the two lymphokines, added together, behaved synergistically to inhibit CFU-GM by up to 70%. The inhibition observed using purified preparations of lymphokines shows that synergy between IFN-gamma and LT is sufficient to explain PHA-CM-induced inhibition of CFU-GM. Our findings suggest that activated T cells regulate hematopoiesis through the release of inhibitory as well as stimulatory factors, and that the simultaneous production of IFN-gamma and LT may represent a mechanism of suppression of hematopoiesis in the cases of bone marrow failure associated with the presence of activated T cells.

Animals↗
PubMed1986

Distinct functional domains on the recombinant human immune interferon molecule.

Two monoclonal antibodies directed against distinct epitopes of recombinant human immune interferon (rIFN-gamma) were used to investigate the relationship between the molecular organization of IFN-gamma and its various biological activities on cultured human melanoma cells. Both monoclonal antibodies inhibited the increase in the expression of cell surface human lymphocyte antigens Class I and II antigens and the antiproliferative and antiviral actions of rIFN-gamma. On the other hand neither monoclonal antibody affected the binding of rIFN-gamma to melanoma cells and its ability to reduce the expression of a high molecular weight-melanoma associated antigen. These data indicate that the functional domains of IFN-gamma responsible for antiviral activity, increased human lymphocyte antigen expression and antiproliferative effects on human melanoma cells may be distinct from that (those) involved in reduced expression of the high molecular weight-melanoma associated antigen and in IFN-gamma binding to cell receptors.

Antibodies, Monoclonal↗
PubMed1985

Natural killer (NK) cell-derived hematopoietic colony-inhibiting activity and NK cytotoxic factor. Relationship with tumor necrosis factor and synergism with immune interferon.

We characterize the natural killer (NK) cell colony-inhibiting activity (CIA) produced in supernatants from cultures of human peripheral blood lymphocytes (PBL) with NK-sensitive target cell lines, and study its relationship with NK cell-derived cytotoxic factor (NKCF). Using monoclonal antibodies (mAb) specific for NK cells or other lymphocyte populations, we unambiguously identify NK cells as the only PBL subset able to produce both NKCF and NK-CIA. We present functional and biochemical data suggesting that NKCF and NK-CIA represent the same molecule: (a) a highly significant positive correlation exists between the quantity of NKCF and NK-CIA in supernatants independently produced by different PBL subsets; (b) both NK-CIA and NKCF are induced by culture of PBL with NK-sensitive, but not with NK-insensitive cell lines, and with HLA-DR+ bone marrow cells; (c) both NKCF and NK-CIA are absorbed on the same cell lines or bone marrow cell types; (d) the two activities coelute in the same gel filtration fractions; (e) D-mannose-6-phosphate blocks both NKCF and NK-CIA activity, and prevents their absorption by K562 cells; and (f) both NKCF and NK-CIA activity are lost after 2 d at 37 degrees C. The NK-CIA-containing preparations are devoid of antiviral activity, and antiinterferon (anti-IFN) antibodies do not block the inhibitor activity of NK-CIA. The effect of NK-CIA on day 14 (early) colony-forming units of granulocytes and macrophages (CFU-GM) is synergistic with that of IFN-gamma, and this synergy is also evident on day 7 (late) CFU-GM growth. A combination of NK-CIA and IFN-gamma suppresses late CFU-GM, at concentrations of the two lymphokines that are completely ineffective when used independently. No synergy between NK-CIA and IFN-alpha or -beta was observed, due to a direct inhibitory effect of these two IFN types on late CFU-GM. Antibodies specific for tumor necrosis factor (TNF), but not those specific for lymphotoxins, inhibit both NK-CIA and NKCF activity in the NK cell-derived supernatant. Recombinant TNF, in the range of concentrations corresponding to that of the cytotoxic activity on L-929 cells present in supernatants, mediated both NKCF and NK-CIA activity.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1985

Inhibition of bone marrow colony formation by human natural killer cells and by natural killer cell-derived colony-inhibiting activity.

Incubation of human peripheral blood lymphocytes with bone marrow cells resulted in significant inhibition of colony formation by committed myeloid and erythroid cells. Using positively selected homogeneous natural killer (NK) cell preparations and lymphocyte subpopulations depleted of or enriched for NK cells, we definitively characterize as NK cells the cells in normal peripheral blood that are responsible for inhibition of bone marrow colony growth. The inhibitory effect of NK cells on hematopoiesis can be mediated by a soluble factor that is produced only by NK cells upon culture with HLA-DR+ hematopoietic cells and with NK-sensitive cell lines. Both NK cells and the NK-produced, colony-inhibiting activity (NK-CIA) are suppressive for allogeneic and autologous bone marrow CFU-GEMM (colony-forming units, granulocyte, erythroid, monocyte, megakaryocyte), CFU-E (CFU, erythroid), and early CFU-GM (CFU, granulocyte, monocyte), but not for either BFU-E (burst-forming units, erythroid) or late CFU-GM. [3H]Thymidine incorporation was inhibited by NK-CIA-containing supernatants in HLA-DR+ but not HLA-DR- bone marrow cell populations stimulated to proliferative by colony-stimulating factor (CSF). These data suggest that the NK cell-mediated inhibitory effect on proliferation and differentiation of hematopoietic precursor cells is mediated in part or completely by the secreted NK-CIA. The concentration of NK-CIA reached in the supernatant of the mixture of NK cell-containing lymphocyte populations with bone marrow cells is sufficient to account for the inhibitory effect mediated by NK cells. Our data support the hypothesis that human NK cells play a major role in the control of hematopoiesis, down-regulating it under conditions in which the NK cells are functionally activated.

Animals↗
PubMed1985

A leukocyte subset bearing HLA-DR antigens is responsible for in vitro alpha interferon production in response to viruses.

In this report, we characterize the major human peripheral blood nonadherent mononuclear cell subset that is responsible for the production in vitro of alpha-interferon (alpha IFN) in response to influenza, Sendai, and Newcastle disease viruses. Using a panel of anti-monocyte, anti-B, anti-T and anti-natural killer cell monoclonal antibodies to purify and recover both positive and negative cell populations, we show that the major alpha IFN-producing cells are HLA-DR(+) cells with no other surface markers characteristic of either lymphocytes or myelomonocytic cells. These cells copurify, on Percoll density gradients, with cells mediating NK activity, but the cell population responsible for alpha IFN production can be distinguished unambiguously from NK cells based on the former's reactivity with an anti-HLA-DR monoclonal antibody, the lack of reactivity with antibodies that detect the low-affinity receptor for IgG on human natural killer cells and granulocytes, and the inability to mediate spontaneous cytotoxicity. Double immunofluorescence assays indicate that cells of this subset, the lineage of which is as yet undetermined but which might be related to dendritic cells, constitute a minor proportion (approximately 1-1.5%) of the nonadherent mononuclear cells from healthy donors.

Antibodies, Monoclonal↗
PubMed1985

Phenotypic characteristics of human natural killer cells.

Surface antigen analysis of human natural killer (NK) cells using anti-lymphocyte monoclonal antibodies identifies NK cells as a discrete cell type (average 15% of peripheral blood lymphocytes) distinct from T, B, and myelomonocytic cells. Virtually all NK cells bear low-affinity Fc receptors for IgG, as detected by antibody B73.1 and N901 antigen; 80-90% of NK cells express the E receptor (OKT11), the C3bi receptor (OKM1), and the T10 antigen; 30-50% are T8 (+), and 30-70% are Leu7 (+). This phenotype is maintained on NK cell-derived clones and on activated NK cells, which are induced to express interleukin 2 receptor (Tac antigen), transferrin receptor, HLA-DR, and several T cell activation antigens but not, like resting NK cells, antigens (T1, T3, T4) characteristic of T cells. On the contrary, NK cell-derived leukemias may express T1 or, more frequently, T3 antigens.

Antigens, Surface↗
PubMed1985

Induction of proliferation in vitro of resting human natural killer cells: expression of surface activation antigens.

In this report, we show that resting human peripheral blood NK cells, positively enriched with antibody B73.1, can be induced to proliferate in vitro in short-term cultures, and newly express membrane activation antigens. B73.1+ NK cells, cultured for 6 days in the presence of conditioned medium containing IL 2 and irradiated B lymphoblastoid cells, show significant [3H]TdR incorporation beginning on day 4. At that time, a large proportion of the cells express HLA-DR and 4F2 antigens, and transferrin and IL 2 receptors, all detectable at high density by indirect immunofluorescence with the use of monoclonal antibodies. These cells maintain their ability to lyse target cells spontaneously or in the presence of antibodies. By two-color immunofluorescence and cell cycle analysis combined with indirect immunofluorescence, we demonstrate directly that the activation antigens are expressed on all NK (B73.1+) cells in the S/G2/M phases of the cell cycle, and on only a proportion of those in the G0/G1 phases.

Animals↗
PubMed1985

Role of immune interferon in the monocytic differentiation of human promyelocytic cell lines induced by leukocyte conditioned medium.

Conditioned medium (CM) from lectin-stimulated human leukocytes contains factors that induce human promyelocytic cell lines to differentiate along the monocytic pathway. In this report, we show that human promyelocytic cell lines are also induced to differentiate along this pathway by immune interferon (IFN gamma). Various preparations of IFN alpha tested did not induce this differentiation. In cultures containing IFN gamma, the cells are induced to coordinately express monocyte markers and functions such as monocyte-specific surface antigens, HLA-DR antigens, nonspecific esterase, receptors for the Fc fragment of IgG, and the ability to mediate antibody-dependent cell-mediated cytotoxicity. Our data indicate that differentiation induced by IFN gamma is not secondary to an arrest of growth of promyelocytic cell lines, but rather that a proportion of cells is induced along a programmed pathway of terminal differentiation similar to that of normal monocytes. CM contains IFN gamma, but its ability to induce differentiation is greater than expected on the basis of its content of IFN gamma. Treatments at 56 degrees C or at pH 2.0, which abolish IFN gamma activity, abrogate the differentiation ability of CM. The antiviral activity and the differentiation activity contained in the CM are coeluted from gel filtration and reverse-phase columns. Monoclonal antibodies anti-IFN gamma, which completely abrogate the differentiation ability of IFN gamma and the antiviral activity in the CM, completely suppress the induction of some monocyte markers by CM, but only reduce the expression of others. When IFN gamma is added to CM, promyelocytic cell lines are induced to differentiate to a much greater extent than that induced by either IFN gamma or IFN gamma-depleted CM alone. These results show that the differentiation activity of leukocyte CM is due to the synergistic effect of IFN gamma and other factors not yet identified.

Animals↗
PubMed1985

Immunochemical analysis of the modulation of human melanoma-associated antigens by DNA recombinant immune interferon.

By utilizing the human melanoma cell line Colo 38, a panel of monoclonal antibodies, and a combination of serologic and immunochemical assays, the effect of recombinant immune interferon (IFN-gamma) on the synthesis, expression, and shedding of a cytoplasmic melanoma-associated antigen (MAA) and of the membrane-bound high m.w. MAA (HMW-MAA), 115K MAA, and 100K MAA has been investigated. IFN-gamma increased the synthesis and shedding of the cytoplasmic MAA, but reduced the synthesis and cell surface expression of the HMW-MAA and of the 100K MAA. The cell surface expression of the 115K MAA on IFN-gamma-treated melanoma cells was reduced, although its synthesis was not markedly changed. The effects were dose-dependent and were related to the incubation time of cells with IFN-gamma. Among the three membrane-bound MAA analyzed, the 100K MAA was the most susceptible to modulation by IFN-gamma. The effects of IFN-gamma preparations are not mediated by contaminants in IFN-gamma preparations because removal of IFN-gamma by affinity chromatography on anti-IFN-gamma monoclonal antibodies abolished its modulating activity. The effects of IFN-gamma on the cytoplasmic MAA are similar to those of leukocyte and fibroblast interferons, whereas those on the membrane-bound MAA are significantly different. The potential implications of the marked changes in the antigenic profile of melanoma cells treated with IFN-gamma are discussed in view of the changes in the immunogenicity of IFN-gamma-treated melanoma cells.

Animals↗
PubMed1984

Response of resting human peripheral blood natural killer cells to interleukin 2.

The present study shows that recombinant interleukin 2 (IL-2) purified to homogeneity induces a rapid and potent enhancement of spontaneous cytotoxicity of human peripheral blood lymphocytes. The cells mediating cytotoxicity after 18-h treatment with IL-2 have surface markers of natural killer (NK) cells and are generated from the peripheral blood subset containing spontaneous cytotoxic cells. A parallel production of gamma interferon (IFN-gamma) is induced by recombinant IL-2 (rIL-2), and NK cells appear to be the major producer cells, whereas T cells are unable to produce IFN-gamma under these experimental conditions. However, the kinetics of the enhancement of cytotoxicity are faster than those of IFN-gamma production, and monoclonal anti-IFN-gamma antibodies do not suppress this effect, making it unlikely that the IFN-gamma produced is responsible for the enhancement. The enhancement of NK cell activity induced by rIL-2 precedes any proliferative response of the lymphocytes, which is instead observed in longer-term cultures of both NK and T cells.

Adjuvants, Immunologic↗
PubMed1984

The Fc receptor for IgG on human natural killer cells: phenotypic, functional, and comparative studies with monoclonal antibodies.

We compare five monoclonal antibodies ( B73 .1, 3G8 , Leu- 11a , Leu- 11b , and VEP13 ) that react with natural killer (NK) cells and polymorphonuclear cells (PMN). We show that all of these antibodies are directed against and inhibit the functional properties of the receptor for the Fc portion of IgG (FcR). Modulation of the FcR on NK cells after reaction with immune complexes induces the disappearance of the antigen(s) recognized by each of the five antibodies. Conversely, the antibodies block binding of IgG-sensitized erythrocytes to the NK cells and PMN and inhibit their ability to mediate cytotoxicity against antibody-sensitized tumor target cells. By using two-color immunofluorescence techniques, we characterize directly the lymphocyte population recognized by these antibodies and show that it is a homogeneous subset that does not bear markers of either B or T cells, with the exception of the 33,000 dalton antigen characteristic of suppressor/cytotoxic T cells present in 20 to 50% of the cells, and the 45,000 dalton receptor for sheep erythrocytes present on 80 to 90% of the cells. The phenotype of the cells reacting with the monoclonal antibodies corresponds to that of NK cells. Cross-competition experiments indicate that these antibodies detect at least two distinct epitopes on FcR, one ( B73 .1) preferentially expressed on NK cells and one or more ( 3G8 /Leu- 11a /Leu- 11b / VEP13 ) preferentially expressed on PMN. The lack of reactivity of these antibodies with B cells suggests that human B cells bear a different FcR from that on NK cells and PMN.

Antibodies, Monoclonal↗
PubMed1984

Antibody 3G8, specific for the human neutrophil Fc receptor, reacts with natural killer cells.

Antibody 3G8 reacts with the receptor for the Fc fragment of aggregated IgG present on the majority of neutrophilic granulocytes and on a small proportion of lymphocytes. In this report, we compare the pattern of reactivity of antibody 3G8 on peripheral blood lymphocytes (PBL) and on polymorphonuclear leukocytes (PMN) with that of antibody B73.1, which reacts with the Fc receptor of natural killer (NK) cells or with a molecule functionally associated with it. We show that 3G8 reacts with the same PBL subset detected by antibody B73.1 and is responsible for virtually all NK cytotoxic activity. The lymphocyte subset recognized by the two antibodies has the morphology of large granular lymphocytes and includes neither B nor T cells. Our results indicate that NK cells and PMN express the same Fc receptor for immune complexes, and that B73.1 and 3G8 recognize on the same receptor two distinct epitopes that are preferentially expressed on NK cells and on PMN, respectively.

Antibodies, Monoclonal↗
PubMed1984

Phorbol esters enhance spontaneous cytotoxicity of human lymphocytes, abrogate Fc receptor expression, and inhibit antibody-dependent lymphocyte-mediated cytotoxicity.

Phorbol esters with tumor promoter activity enhance the spontaneous cytotoxicity of human lymphocytes against a variety of target cell lines, with an efficiency that correlates with their potency as tumor promoters or skin irritants. Analysis of surface marker expression of the lymphocytes cytotoxic after treatment with phorbol ester identified the cytotoxic cell subset as that containing natural killer cells. Although gamma-interferon (IFN gamma) is produced by T cells treated with phorbol esters, IFN gamma is probably not the mediator of enhancement of natural killer cell activity, because anti-IFN gamma antibodies failed to block this enhancement. Spontaneous cell-mediated cytotoxicity is inhibited when phorbol esters are present during the cytotoxic assay, but is enhanced when the effector cells are pretreated with these agents. On the other hand, antibody-dependent cytotoxicity mediated by lymphocytes is inhibited by phorbol ester pretreatment of the effector cells or by phorbol esters present during the cytotoxic assay. Treatment of lymphocytes with phorbol esters at 37 degrees C, but not at 4 degrees C, completely abrogates in 1 to 2 hr the expression of the receptor for the Fc fragment of IgG, as detected by rosette formation with IgG-sensitized erythrocytes and by reactivity with anti-Fc receptor antibodies. The inhibition of antibody-dependent cytotoxicity by phorbol esters is probably secondary to their effect on the Fc receptor.

Animals↗
PubMed1984

The cytotoxic effector cells in preparations of adherent mononuclear cells from human peripheral blood.

We have characterized the effector cells present in fresh adherent cell preparations from human peripheral blood that are responsible for the lysis of K562 and IgG antibody-sensitized P815Y target tumor cells. Purified lymphocytes and monocytes, separated from adherent cell preparations by using techniques that utilized light scatter properties and reactivity of the cells with monoclonal antibodies, were used as effectors for the spontaneous and antibody-dependent cytotoxicity. The role of monocytes was also studied at the single cell level. Our results indicate that when a subpopulation of adherent cells that is B73.1+ (NK cells), B44.1- (non-monocyte), with light scatter characteristics of lymphocytes, is removed from the total adherent cell population, the resultant purified monocytes are unable to spontaneously kill K562 target cells. This data suggests that fresh unstimulated adherent cell cytotoxicity against K562 cells is mediated by lymphocyte contamination in these preparations and that the cell responsible for this killing is probably the NK cell. In contrast antibody-dependent cellular cytotoxicity against P815Y target cells is mediated by monocytes and lymphocytes.

Antibodies, Monoclonal↗
PubMed1983

Immune interferon and leukocyte-conditioned medium induce normal and leukemic myeloid cells to differentiate along the monocytic pathway.

Conditioned medium from phytohemagglutinin-stimulated human leukocytes contains a factor that can induce promyelocytic cell lines and certain acute myelogenous leukemia cells to differentiate along the monocytic pathway. In this report, we show that immature myeloid cells from normal bone marrow or the peripheral blood of patients with chronic myelogenous leukemia can be induced to differentiate to monocyte-like cells by immune gamma interferon (IFN gamma). We have identified IFN gamma as the predominant differentiation factor contained in the conditioned medium. Purified or recombinant IFN gamma, but not various preparations of IFN alpha or beta, can induce monocytic differentiation in myeloid cells. In cultures containing conditioned medium, the cells fail to continue myeloid maturation, and are induced to express monocyte markers and functions, such as monocyte-specific surface antigens, HLA-DR antigens, Fc receptors for monomeric immunoglobulins, nonspecific esterase, and the ability to mediate antibody-dependent, cell-mediated cytotoxicity. Even myeloid cells as mature as metamyelocytes or band cells can be induced by IFN gamma to undergo monocyte differentiation, but monocyte-specific or HLA-DR antigens are not induced in mature neutrophils. These findings reveal a previously unknown, specific function of human IFN gamma and offer new insights to the regulation of monocyte recruitment and differentiation during a virus infection or immune response.

Bone Marrow Cells↗