Search PubMed⌕ Search

Biomedical subjects

G Trinchieri

Publications and source records attributed to G Trinchieri.

At least 91 records · Page 5Linked to original sources
PubMed1997

Inhibition of human interleukin-12 production by pentoxifylline.

Pharmacological control of interleukin-12 (IL-12) production may be a key therapeutic strategy for modulating immunological diseases dominated by type-1 cytokine responses. In this study, we investigated the effects of pentoxifylline on the production of IL-12 by human blood mononuclear cells and primary human monocytes stimulated with heat-killed Staphylococcus aureus Cowan strain I (SAC) or lipopolysaccharide (LPS). Pentoxifylline potently suppressed production of IL-12 in a concentration-dependent manner. In these same experiments, tumour necrosis factor-alpha (TNF-alpha) production was inhibited and IL-10 and prostaglandin E2 (PGE2) production was enhanced by treatment with pentoxifylline. Suppression of IL-12 production by pentoxifylline was found to be independent of several known endogenous inhibitors of IL-12, such as IL-10, transforming growth factor-beta (TGF-beta), IL-4 and PGE2. RNase protection assays revealed that pentoxifylline inhibited accumulation of both IL-12 p40 and p35 mRNA, suggesting a predominant mRNA locus for pentoxifylline-induced IL-12 inhibition. Low levels of pentoxifylline added to the suppression of IL-12 production by suboptimal inhibiting doses of dexamethasone, suggesting that this drug combination may have therapeutic utility. These results provide a firm rationale for the use of pentoxifylline in clinical trials of immunological disorders characterized by inappropriate type-1 immune responses.

Cell Culture Techniques↗
PubMed1997

Function and clinical use of interleukin-12.

Interleukin-12 is a heterodimeric cytokine produced by phagocytic cells, professional antigen-presenting cells such as dendritic cells and skin Langerhans cells, and B cells. Interleukin-12 production is induced by bacteria, intracellular pathogens, fungi, viruses, or their products in a T-cell-independent pathway or a T-cell-dependent pathway, the latter mediated through CD40 ligand-CD40 interaction. Interleukin-12 is produced rapidly after infection and acts as a proinflammatory cytokine eliciting production of interferon gamma, by T and natural killer cells, which activates phagocytic cells. The production of interleukin-12 is strictly regulated by positive and negative feedback mechanisms. If interleukin-12 and interleukin-12-induced interferon gamma are present during early T-cell expansion in response to antigen, T-helper type-1 cell generation is favored and generation of T-helper type-2 cells is inhibited. Thus interleukin-12 is also a potent immunoregulatory cytokine that promotes T-helper type-1 differentiation and is instrumental in the T-helper type-1-dependent resistance to infections by bacteria, intracellular parasites, fungi, and certain viruses. By inhibiting T-helper type-2 cell response, interleukin-12 has a suppressive effect on allergic reactions; by promoting T-helper type-1 responses it participates in the immunopathology responsible for several organ-specific autoimmune diseases. Viruses inducing a permanent or transient immunodepression, such as HIV and measles, may act, in part, by suppressing interleukin-12 production. Because of its ability to enhance resistance to several infectious diseases and to act as an adjuvant in vaccination, and because of its powerful antitumor effect in vivo, interleukin-12 is currently in clinical trials in cancer patients and HIV-infected patients, and it is being considered for therapeutic use in other diseases.

Animals↗
PubMed1997

Calcitonin gene-related peptide inhibits proliferation and antigen presentation by human peripheral blood mononuclear cells: effects on B7, interleukin 10, and interleukin 12.

CGRP is a neuropeptide that has previously been described to possess immunosuppressive activities. CGRP is released from peripheral nerves that, in the skin, are in close physical association with dendritic APC. We sought to investigate the mechanisms by which CGRP can inhibit immune responses by studying its effects on human peripheral blood mononuclear cells (PBMC). Using allogeneic monocytes as stimulator cells, CGRP could inhibit the proliferation of PBMC by 47% when CGRP was present for the duration of culture. Interestingly, when the stimulator monocytes were incubated with CGRP for 2 h prior to irradiation then washed, the observed inhibition increased to 85%, suggesting that CGRP was exerting a direct effect on the monocyte stimulator population. Finally, the recall response to tetanus toxoid (TT) by PBMC from individuals vaccinated with TT 14 d prior was inhibited by 25-50% in the presence of CGRP. Also, CGRP decreased the levels of B7.2 but not B7.1 on treated monocytes, and this inhibition could be abrogated by the addition of anti-IL-10 antibody, suggesting that the inhibition was mediated by an increase in IL-10 production. Moreover, increased IL-10 production was confirmed by ELISA. Both IL-12 p40 and IFN-gamma levels in CGRP-treated cultures were found to be decreased by approximately 30%. The decrease in IL-12 p40 levels could be reversed by addition of anti-IL-10. These data suggest that CGRP inhibits PBMC proliferation, in part, through the release of IL-10, which in turn can downregulate important co-stimulatory molecules and the cytokines IL-12 and IFN-gamma.

Antigen Presentation↗
PubMed1996

The potential therapeutic role of interleukin-12 in cutaneous T-cell lymphoma.

Cutaneous T-cell lymphoma (CTCL) is a lymphoproliferative disorder characterized by skin invasion of clonally derived malignant CD4+ lymphocytes that phenotypically resemble mature T-helper (Th) cells. Sezary syndrome (SzS) represents an advanced form of CTCL associated with generalized erythroderma and involvement of the peripheral blood by the malignant cell population. We have previously demonstrated aberrant cytokine production by peripheral blood mononuclear cells (PBMCs) in SzS characterized by increased IL-4 and deficient IL-2 and IFN-gamma production, as well as increased expression of mRNA for IL-4 and IL-5 within active skin lesions, indicating that the clonal T-cell population is likely derived from the T-helper type 2 (Th2) subset of helper T lymphocytes. Furthermore, a variety of immune abnormalities have been observed in association with SzS that have been attributed to the cytokine abnormalities. Because IL-12 is a potent inducer of IFN-gamma production and causes the activation of cytotoxic lymphocytes, we assessed the production of IL-12 by PBMCs from SzS patients, and whether IL-12 could alter the unfavorable cytokine balance typical of SzS and, thus, possibly lead to correction of immune defects. In this review, we present our data, which indicate that patients with SzS exhibit marked defects in monocyte production of IL-12 p70. Moreover, in vitro culture of PBMC from SzS patients with recombinant IL-12 leads to reconstitution of normal IFN-gamma production and markedly enhances cell-mediated cytotoxicity.

Cells, Cultured↗
PubMed1996

Enhancement of porcine natural killer cell activity by recombinant human and murine IL-12.

These studies describe the effects of recombinant human (rHu) and recombinant murine (rMu) interleukin 12 (IL-12) in the porcine system. To examine the effects of rHu and rMu IL-12, porcine PBL were cultured with rHu and rMu IL-12, and then used for a NK assay. Significant enhancement of porcine NK cell cytotoxicity was observed, and maximal enhancement was reached after 26 hr culture in nanogram quantities (5 ng/ml = 10 units/ml) of rHu and rMu IL-12. Monoclonal antibody (mAb) specific for human IL-12, C8.6, blocked rHu IL-12 enhanced porcine natural killer (NK) cytotoxicity. It was also shown that rHu IL-12 had additive effects on enhancement of NK cell cytotoxicity with PNK-E/G7 mAbs which react with cytolytic trigger molecules on porcine NK cells. By using purified NK cells, porcine tumor necrosis factor-alpha (TNF-alpha) secretion was measured on rHu IL-12 and PNK-E/G7 mAb-activated NK cells. rHu IL-12 and PNK-E/G7 mAbs synergize to induce TNF-alpha secretion. These data indicate that rHu and rMu IL-12 are cross-reactive in the porcine system and suggest the potential use of the porcine system as an important animal model for further study of rHu IL-12.

Animals↗