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Biomedical subjects

G Trinchieri

Publications and source records attributed to G Trinchieri.

At least 163 records · Page 9Linked to original sources
PubMed1994

Cooperation of natural killer cell stimulatory factor/interleukin-12 with other stimuli in the induction of cytokines and cytotoxic cell-associated molecules in human T and NK cells.

The ability of natural killer cell stimulatory factor/interleukin-12 (IL-12) to induce cytokines other than IFN-gamma from both T and NK cells was studied. Both the direct effect of IL-12 and the cooperation between IL-12 and other cytokine inducers such as IL-2, phorbol diesters, and receptor antibodies were evaluated. It was found that IL-12 induces mRNA accumulation and production of GM-CSF and TNF-alpha from both T and NK cells and, as tested on NK cells only, induces M-CSF mRNA accumulation. Compared with cytokine inducers, IL-12 ability to induce IFN-gamma production was severalfold higher than its ability to induce GM-CSF or TNF-alpha. Likewise, the synergistic effect of IL-12 with the other stimuli to induce IFN-gamma was stronger than that observed in the case of GM-CSF or TNF-alpha. The IL-12-mediated enhancement of NK cytotoxicity is accompanied by an increased accumulation of mRNA for at least two genes encoding cytotoxic cell granule-associated proteins, the serine esterase granzyme B and the pore-forming protein perforin. IL-12 induction of perforin mRNA accumulation was not synergistic with either IL-2 or anti-CD16 stimulation, whereas granzyme B mRNA accumulation, induced by IL-2 or anti-CD16 stimulation, was slightly potentiated by IL-12. Thus, although IFN-gamma production is probably one of the most physiologically relevant effects of IL-12, induction of other cytokines by IL-12 in the presence of other inflammatory or immune stimuli may have a role in the in vivo functions of IL-12. The observation that both the IL-12-mediated enhancement of NK cell-mediated cytotoxicity and the increased expression of genes encoding cytotoxic cell granule-associated proteins were not cooperative with the effect of other NK cell activators suggests that the effect of IL-12 on cytotoxic cells is in part independent from that of other stimuli regulating the functions of these cells.

CD3 Complex↗
PubMed1994

Interleukin-12: a bridge between innate resistance and adaptive immunity with a role in infection and acquired immunodeficiency.

Interleukin-12 (IL-12) is a disulfide-linked heterodimeric cytokine originally identified as a product of EBV-transformed B cell lines. Monocyte/macrophages are the physiologically most relevant producers of IL-12, in response to both Gram-positive and -negative bacteria, bacterial products, and intracellular parasites. Although IL-12 has an enhancing effect on the survival and growth of early hematopoietic progenitor cells, most of the IL-12 biological activity has been described on T and NK cells, on which it induces production of lymphokines, primarily IFN-gamma, enhances cytotoxic activity, and, in cooperation with other stimuli, increases proliferation. IL-12 is an inducer of development of T helper type 1 (Th-1) cells and the equilibrium between IL-12 and IL-4 is probably important for the balance in vivo between Th-1 and Th-2 responses. IL-12 has an important role in the host resistance to infection, in particular to intracellular pathogens, by activating macrophages through induction of IFN-gamma from NK and T cells and by enhancing cell-mediated immune responses, dependent on Th-1 cell development. Peripheral blood mononuclear cells from HIV-seropositive individuals are impaired in their ability to produce IL-12 in response to bacterial stimulation, and IL-12 restores in vitro some of the depressed immunological functions, suggesting that a defect in IL-12 production may have a pathogenic role in the immunodeficiency of HIV-infected individuals. Natural IL-12 appears to provide a regulatory link between innate resistance and the development of the antigen-specific adaptive immune response and the recombinant protein has therapeutic potential because of its activity against tumors and infections and its effectiveness as an adjuvant enhancing cell-mediated immunity in vaccination.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Infection with Leishmania major induces interleukin-12 production in vivo.

Experimental infections of mice with the protozoan parasite Leishmania major provide an excellent model for defining the conditions required for generation of CD4+ Th1 and Th2 cells in vivo. Since interleukin-12 (IL-12) has been implicated in the development of Th1 cells, we investigated whether L. major stimulates IL-12 production in vitro or in vivo. Surprisingly, macrophages cultured in vitro failed to produce IL-12 following L. major infection. In contrast, lymph node cells from C3H mice infected for 2 days with L. major produced elevated levels of IL-12. In order to determine if the inability to stimulate IL-12 production was limited to in vitro infections, we infected macrophages in vivo by inoculating L. major into the peritoneal cavity. Peritoneal cells isolated 24 h later exhibited a significant increase in the number of cells producing IL-12. In addition, supernatants harvested from these cells following culture contained elevated levels of IL-12. These data indicate that L. major infection induces increased IL-12 production in mice.

Animals↗
PubMed1993

Identification of a novel signal transduction surface molecule on human cytotoxic lymphocytes.

In this study, we have used a newly generated monoclonal antibody (mAb C1.7) to identify a novel 38-kD signal-transducing surface molecule (p38) expressed by lymphocyte subsets capable of cell-mediated cytotoxicity. Virtually all CD16+/CD56+ natural killer (NK) cells and approximately half of CD8+ (T cell receptor [TCR] alpha/beta+) T cells and TCR-gamma/delta+ T cells express the p38 surface molecule. Stimulation of p38 on NK cells with mAb C1.7 activated cytotoxicity, induced lymphokine production, and initiated polyphosphoinositol turnover and [Ca2+]i increases. Unlike other NK cell surface molecules that activate cytotoxicity, p38 stimulation did not result in the release of the granule enzyme N-carbobenzoxy-L-thiobenzyl ester-esterase even under conditions in which mAb C1.7 induced NK cell-mediated redirected lysis of Fc gamma R+ target cells. Activated (recombinant interleukin 2 [rIL-2], 5 d) CD8+ T cells mediated non-major histocompatibility complex (MHC)-restricted cytotoxicity, and the CD8+/p38+ subset contained the overwhelming majority of this activity. F(ab')2 fragments of mAb C1.7 inhibited non-MHC-restricted cytotoxicity mediated by resting NK cells and rIL-2-cultured T cells but did not affect spontaneous cytotoxicity mediated by activated, cultured NK cells. Taken as a whole, our results suggest that p38 may have a direct role in the recognition, signal transduction, and/or lytic mechanisms of non-MHC-restricted cytotoxicity.

Animals↗
PubMed1993

Interleukin 10 (IL-10) inhibits human lymphocyte interferon gamma-production by suppressing natural killer cell stimulatory factor/IL-12 synthesis in accessory cells.

Natural killer cell stimulatory factor or interleukin 12 (NKSF/IL-12) is a heterodimeric cytokine produced by monocytes/macrophages, B cells, and possibly other accessory cell types primarily in response to bacteria or bacterial products. NKSF/IL-12 mediates pleiomorphic biological activity on T and NK cells and, alone or in synergy with other inducers, is a powerful stimulator of interferon gamma (IFN-gamma) production. IL-10 is a potent inhibitor of monocyte-macrophage activation, that inhibits production of tumor necrosis factor alpha (TNF-alpha), IL-1 and also IFN-gamma from lymphocytes acting at the level of accessory cells. Because TNF-alpha and IL-1 are not efficient inducers of IFN-gamma, the mechanism by which IL-10 inhibits IFN-gamma production is not clear. In this paper, we show that IL-10 is a potent inhibitor of NKSF/IL-12 production from human peripheral blood mononuclear cells activated with Staphylococcus aureus or lipopolysaccharide (LPS). Both the production of the free NKSF/IL-12 p40 chain and the biologically active p70 heterodimer are blocked by IL-10. NKSF/IL-12 p40 chain mRNA accumulation is strongly induced by S. aureus or LPS and downregulated by IL-10, whereas the p35 mRNA is constitutively expressed and only minimally regulated by S. aureus, LPS, or IL-10. Although IL-10 is able to block the production of NKSF/IL-12, a powerful inducer of IFN-gamma both in vitro and in vivo, the mechanism of inhibition of IFN-gamma by IL-10 cannot be explained only on the basis of inhibition of NKSF/IL-12 because IL-10 can partially inhibit IFN-gamma production induced by NKSF/IL-12, and also, the IFN-gamma production in response to various stimuli in the presence of neutralizing antibodies to NKSF/IL-12. Our findings that antibodies against NKSF/IL-12, TNF-alpha, or IL-1 beta can significantly inhibit IFN-gamma production in response to various stimuli and that NKSF/IL-12 and IL-1 beta can overcome the IL-10-mediated inhibition of IFN-gamma, suggest that IL-10 inhibition of IFN-gamma production is primarily due to its blocking production from accessory cells of the IFN-gamma-inducer NKSF/IL-12, as well as the costimulating molecule IL-1 beta.

Antigen-Presenting Cells↗
PubMed1993

Production of tumor necrosis factor and other proinflammatory cytokines by human mononuclear phagocytes stimulated with myelin P2 protein.

In this study we examined the effect of myelin P2 protein on some proinflammatory functions exerted by human mononuclear phagocytes. Northern blot analysis demonstrated that P2 protein selectively induced in monocytes and macrophages mRNA accumulation of tumor necrosis factor (TNF), interleukin 1 beta (IL-1 beta), and interleukin 8 (IL-8) in a time-dependent manner. Natural killer stimulating factor (IL-12) mRNA and protein secretion was strongly induced by lipopolysaccharide but not by P2 protein. Supernatants harvested from P2-stimulated monocytes contained significant amounts of TNF, IL-1 beta, and IL-8, whereas those from macrophages contained only TNF and IL-8. The effect of the P2 protein on TNF and IL-8 mRNA accumulation and secretion was not affected by polymyxin B, which, on the other hand, almost completely abolished the effect of lipopolysaccharide. Finally, P2 protein did not directly trigger hydrogen peroxide release but, through the induced release of TNF, potentiated monocyte respiratory burst capability. Since P2 protein is the antigen responsible for the induction of experimental allergic neuritis, these findings identify a potential mechanism involved in the inflammatory reaction and myelin damage during experimental allergic neuritis.

Cytokines↗
PubMed1993

Regulation of hematopoiesis in vitro by alloreactive natural killer cell clones.

Natural killer (NK) cells lyse autologous and allogeneic target cells even in the absence of major histocompatibility complex (MHC) class I antigens on the target cells. Recently, however, human allospecific NK cell clones have been generated that recognize at least five distinct specificities inherited recessively and controlled by genes linked to the MHC. Because the genetic specificity of these alloreactive NK cells in vitro appears analogous to that of in vivo NK cell-mediated murine hybrid resistance, i.e., the rejection of parental bone marrow in irradiated F1 animals, we tested the ability of human alloreactive NK clones to recognize allogeneic hematopoietic progenitor cells. NK cells from two specificity 1 alloreactive NK clones, ES9 and ES10, significantly and often completely suppressed colony formation by purified peripheral blood hematopoietic progenitor cells from specificity 1-susceptible donors, but had no significant effect on the cells of specificity 1-resistant donors. Activated polyclonal NK cells were less efficient than the NK clones in inhibiting colony formation and had a similar effect on cells from both specificity 1-susceptible and -resistant donors. The alloreactive NK clones produced cytokines with a suppressive effect on in vitro hematopoiesis, such as interferon gamma (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha), when exposed to phytohemagglutinin blasts from specificity 1-susceptible, but not -resistant donors. However, the mechanism by which alloreactive NK cells inhibit colony formation is more consistent with a direct cytotoxic effect than with the production of inhibitory cytokines because antibodies (anti-IFN-gamma, alpha-TNF-alpha, and -lymphotoxin) that completely blocked the inhibition by polyclonal NK cells had only a minimal effect on the inhibition by the alloreactive clones. Moreover, the alloreactive clones were directly cytolytic in a 51Cr release assay against enriched preparations of peripheral blood progenitor cells from specificity 1-susceptible donors. These data indicate that the alloreactive NK cells are likely the human counterpart of the cells mediating murine hybrid resistance and that these cells might play clinically important roles in rejection or in graft-versus-leukemia reactions after allogeneic bone marrow transplantation.

Cell Line↗
PubMed1993

Natural killer cell stimulatory factor (interleukin 12 [IL-12]) induces T helper type 1 (Th1)-specific immune responses and inhibits the development of IL-4-producing Th cells.

The effects exerted on the in vitro development of antigen-specific T cell lines and T cell clones by addition or neutralization of interleukin 12 (IL-12) in lymphocyte bulk culture were examined. T cell lines specific for Dermatophagoides pteronyssinus group I (Der p I) derived in the presence of IL-12 exhibited reduced ability to produce IL-4 and increased ability to produce interferon gamma (IFN-gamma), and developed into Der p I-specific CD4+ T cell clones showing a T helper type 0 (Th0)- or Th1-, instead of Th2-, like cytokine profile. In contrast, purified protein derivative (PPD)-specific T cell lines derived in the presence of anti-IL-12 antibody exhibited an increased ability to produce IL-4 and developed into PPD-specific CD4+ T cell clones showing a Th0-, instead of Th1-, like profile. The influence of IL-12 on the cytokine secretion profile of Der p I-specific T cell lines was not prevented by addition to lymphocyte bulk cultures of anti-IFN-gamma antibody, but could be at least partially inhibited by the removal from bulk cultures of CD16+ cells. Thus, IL-12 and CD16+ cells appear to have inhibitory effects on the development of IL-4-producing cells and to play an inductive role in promoting Th1-like responses.

Animals↗
PubMed1993

Enhancing effect of natural killer cell stimulatory factor (NKSF/interleukin-12) on cell-mediated cytotoxicity against tumor-derived and virus-infected cells.

Natural killer cell stimulatory factor (NKSF) or interleukin-12 (IL-12) is a heterodimeric cytokine with pleiomorphic effects on T and NK cells, including induction of lymphokine production, mitogenesis, and enhancement of spontaneous cytotoxic activity. Similarly to IL-2, NKSF/IL-12 enhances NK cell-mediated cytotoxicity within a few hours and independently from induced proliferation. This effect is independent from other induced cytokines, because it is not prevented by antibodies neutralizing interferon (IFN)-alpha, IFN-beta, IFN-gamma, IL-2 or tumor necrosis factor (TNF)-alpha and, unlike the induction of IFN-gamma production by peripheral blood lymphocytes, it does not require HLA class II-positive accessory cells. Enhanced cytotoxicity is accompanied by morphologic changes in NK cells, including a significant increase in the number of cytoplasmic granules. In addition to the previously described ability to enhance the cytotoxic activity of NK cells against tumor-derived target cells, NKSF/IL-12 is also a potent stimulator of cytotoxicity against virus-infected cells, either fibroblasts acutely infected with herpes viruses or T cell lines chronically infected with human immunodeficiency virus-1. NK cell-mediated antibody-dependent cytotoxicity or anti-CD16 antibody-redirected lysis is not significantly enhanced by NKSF/IL-12. However, the ability of resting peripheral blood T cells to mediate anti-CD3 antibody-redirected lysis is enhanced by 18-h incubation with NKSF/IL-12, indicating that this lymphokine can modulate the cytotoxic capability of both NK and T cells.

Animals↗
PubMed1993

Cytokine cross-talk between phagocytic cells and lymphocytes: relevance for differentiation/activation of phagocytic cells and regulation of adaptive immunity.

Cytokines represent one of the most important elements in the communication among different cell types. They play an increasingly better understood role in the communication among hematopoietic cells and in particular in the reciprocal regulation of effector cell types of innate or natural resistance (phagocytic cells and Natural Killer (NK) cells) and those of adaptive immunity (T and B lymphocytes). Lymphocytes produce several cytokines with either stimulatory (e.g., colony stimulatory factor) or suppressive (e.g., tumor necrosis factors and interferons) effects on proliferation of early hematopoietic cells. Many of these cytokines, alone or acting in synergistic combinations, also have a differentiation-inducing ability on immature myeloid cells and act as powerful potentiators of the cellular functions of terminally differentiated phagocytic cells. The communication between lymphocytes and phagocytic cells is not unidirectional, as phagocytic cells produce factors that regulate lymphocyte activation. In addition to their role as antigen presenting cells expressing costimulatory accessory molecules and secreting cytokines (e.g., IL-1, IL-6, TNF), phagocytic cells have been recently shown to produce Natural Killer cell Stimulatory Factor (NKSF/IL-12). IL-12 is a heterodimeric cytokine with important modulatory functions on cytotoxicity of NK and T cells, lymphocyte proliferation, lymphokine production, and development of T helper cell subsets. These communications between phagocytic cells and lymphocytes are further regulated by negative and positive feedback mechanisms that contribute to maintain the homeostasis of the system in physiologic conditions and to govern the changes in this equilibrium needed for the response to infectious or other foreign agents.

Animals↗
PubMed1993

Characterization of a human monocyte antigen, B148.4, regulated during cell differentiation and activation.

We analyzed the phenotypic changes associated with monocyte activation and differentiation using a newly developed monoclonal antibody (B148.4). Among peripheral blood leukocytes, the antigen recognized by this antibody is expressed on monocytes and granulocytes at high and low density, respectively. Antigen expression is lost during in vitro differentiation of monocytes and is absent on tissue macrophages, indicating that expression of this antigen is related to monocyte differentiation. Only 1 alpha,25-dihydroxyvitamin D3 and phorbol diesters, of several inducers tested, up-regulate B148.4 antigen expression on cells (monocytes and certain myeloid cell lines) that constitutively bear the antigen, without, however, allowing its maintenance during monocytic differentiation or inducing it on negative cells. By immunoprecipitation from B148.4+ U937 cells, the antigen is a complex of a major 116-kd and two minor 38- and 46-kd molecules. Analysis of eight different tissues reveals that the antigen is shared with endothelial cells. Biochemical characteristics, cellular distribution, and expression pattern on monocytes, myeloid cell lines, and AML cells upon culture with different stimuli indicate that B148.4 is a novel monocyte differentiation antigen.

Antibodies, Monoclonal↗
PubMed1993

Differential effects of tyrosine kinase inhibition in CD69 antigen expression and lytic activity induced by rIL-2, rIL-12, and rIFN-alpha in human NK cells.

The effect of rIL-12 on induction of CD69 antigen expression and cytolytic activity in purified human NK cells was evaluated in comparison to the effects of rIL-2 and rIFN-alpha. It was found that rIL-12 directly induced CD69 antigen expression in NK cells, although the period of incubation required by rIL-12 was longer than the period required by rIL-2 or by rIFN-alpha. Similarly, the cytolytic activity induced by rIL-12 in NK cells against the NK-resistant target cell line Raji was consistently lower than the cytolytic activity induced by rIL-2 or rIFN-alpha when measured after 6 hr of incubation, and increased during the following 18 hr of incubation. To compare the involvement of tyrosin kinases in activation of NK cells induced by rIL-2, rIL-12, and rIFN-alpha, the effect of the specific inhibitor of tyrosin kinases, genistein, was evaluated on induction of CD69 antigen expression and lytic function mediated by the three cytokines. It was found that genistein inhibited CD69 antigen expression induced by rIL-2 and by rIL-12, but not that induced by rIFN-alpha. Unlike the effect on CD69 antigen expression, the cytolytic activity induced by all three cytokines was inhibited by genistein. These results, together with the finding that CD69 antigen expression induced by rIL-2 but not by rIL-12 or rIFN-alpha was inhibited by addition of rIL-4, strongly suggest that IL-2, IL-12, and IFN-alpha mediate their effects, leading to induction of CD69 antigen expression through different activation pathways.

Antigens, CD↗
PubMed1993

Interleukin-12 and its role in the generation of TH1 cells.

Over the past few years a growing number of new cytokines have been discovered. Here, Giorgio Trinchieri reports on one of these, Interleukin 12, and discusses the significance of the many effects it has on the regulation of immunity and its importance to the generation of TH1 cells.

Allergy and Immunology↗
PubMed1992

Natural killer (NK) cell stimulatory factor or IL-12 has differential effects on the proliferation of TCR-alpha beta+, TCR-gamma delta+ T lymphocytes, and NK cells.

We have analyzed the effects of NK cell stimulatory factor/IL-12, on proliferation of PBL and their subsets. IL-12 synergizes with lectins and phorbol diesters to induce proliferation of CD4+ and CD8+ peripheral blood T lymphocytes. In the case of phorbol-diester-induced proliferation, the effect of IL-12 is in part mediated by induced IL-2 production, as suggested by the observation that IL-12 enhances IL-2 production in these cultures and that anti-IL-2 antibodies inhibit proliferation. IL-12 synergizes also with anti-CD3 antibodies and with allogeneic stimulation in MLC in inducing T cell proliferation. IL-12 alone is mitogenic for preactivated T and NK lymphoblasts. This mitogenic effect is observed with similar doses of IL-12 on NK lymphoblasts as well as on CD4+ and CD8+ TCR-alpha beta+ and on TCR-gamma delta+ lymphoblasts. On TCR-alpha beta+ T lymphocytes the effect of IL-12 is always additive to that of IL-2 over a wide dose range. The same effect is observed on highly activated, actively proliferating NK cells. However, on NK and TCR-gamma delta+ lymphoblasts reverting to a resting state after stimulation and on a TCR-gamma delta+ acute leukemia-derived T cell line, IL-12 inhibits significantly the proliferation induced by moderate to high doses (10 to 100 U/ml) of IL-2. This inhibitory effect is, at least in part, indirect, and depends on IL-12-induced production of TNF. Neutralizing anti-TNF antibodies, but not anti-IFN-gamma and anti-transforming growth factor antibodies, restore by more than 70% the inhibition of proliferation induced by IL-12 in these cultures. However, TNF alone cannot mimic the inhibitory effect of IL-12 on the IL-2-induced proliferation of NK and TCR-gamma delta+ lymphoblasts, suggesting the involvement of additional mechanisms. The relevance of these findings for the biology of lymphocyte subsets mediating MHC nonrestricted cytotoxicity is discussed.

Flow Cytometry↗