PubMed Health⌕ Search

Biomedical subjects

Michel Goldman

Publications and source records attributed to Michel Goldman.

At least 19 recordsLinked to original sources
PubMed2007

Interferon regulatory factor 3-dependent responses to lipopolysaccharide are selectively blunted in cord blood cells.

The synthesis of interferon-beta (IFNbeta) and IFN-inducible factors elicited by lipopolysaccharide (LPS) depends on the transcriptional activity of interferon regulatory factor 3 (IRF-3) downstream of Toll-like receptor-4 (TLR4). To examine the ability of human newborns to mount TLR4-mediated IRF-3-dependent responses, we analyzed the pattern of genes expressed on the addition of LPS to cord blood or cord blood monocyte-derived dendritic cells (moDCs). Expression of IFNbeta and IFN-inducible genes was selectively impaired in neonatal blood and moDCs as compared with their adult counterparts. This selective defect was confirmed by microarray experiments on moDCs. Altered expression of IFN-inducible genes was related to impaired IFNbeta synthesis because IFNbeta signaling was functional in neonatal moDCs. However, addition of exogenous IFNbeta failed to restore LPS-induced IL-12p70 synthesis which was previously shown to be defective in neonatal moDCs. Although LPS-induced IRF-3 nuclear translocation was observed both in adult and neonatal moDCs, IRF-3 DNA-binding activity and association with the coactivator CREB-binding protein (CBP) were decreased in neonatal as compared with adult moDCs. We conclude that impaired IRF-3/CBP interaction in neonatal blood cells exposed to LPS is associated with impaired expression of IFNbeta and IFN-inducible genes. Because IRF-3 activity is also required for IL-12p70 synthesis, our findings provide a molecular basis for the decreased ability of LPS-stimulated neonatal moDCs to elicit Th1-type responses.

Active Transport, Cell Nucleus↗
PubMed2006

Antigen-specific central memory CD4+ T lymphocytes produce multiple cytokines and proliferate in vivo in humans.

The function of Ag-specific central (T(CM)) and effector (T(EM)) memory CD4+ T lymphocytes remains poorly characterized in vivo in humans. Using CD154 as a marker of Ag-specific CD4+T cells, we studied the differentiation of memory subsets following anti-hepatitis B immunization. Hepatitis B surface Ag (HBs)-specific memory CD4+T cells were heterogeneous and included T(CM) (CCR7+CD27+) and T(EM) (CCR7(-)CD27(+/-)). HBs-specific T(CM) and T(EM) shared the capacity to produce multiple cytokines, including IL-2 and IFN-gamma. Several years postimmunization, approximately 10% of HBs-specific memory CD4+ T cells were in cycle (Ki67+) and the proliferating cells were CCR7+. These results suggest that the model of functional specialization of T(CM) and T(EM) cannot be applied to protein vaccine Ags and support the concept that T(CM) are capable of self-renewal and contribute to maintain the pool of memory cells.

Adult↗
PubMed2006

Rottlerin inhibits human T cell responses.

Rottlerin is a pharmacological inhibitor of protein kinase C (PKC) theta, a novel PKC selectively expressed in T lymphocytes. PKC theta is known to regulate T cell receptor (TCR)/CD28 signalling pathways in T lymphocytes, but the impact of PKC theta inhibition on human T cell responses remains undefined. In this work, we describe the effects of rottlerin on the responses of CD4+ and CD8+ human T lymphocytes upon polyclonal activation. We observed a dose-dependent inhibition of CD4+ and CD8+ T cell proliferation in response to anti-CD3/anti-CD28 antibodies stimulation in the presence of rottlerin. This inhibition was associated with impaired CD25 expression and decreased interleukin (IL)-2 production in activated T cells. In contrast, rottlerin did not alter IL-2-induced T cell proliferation. Furthermore, we demonstrated that rottlerin blocked interferon (IFN) gamma, IL-10 and IL-13 mRNA expression in TCR/CD28 activated CD4+ T cells. These findings place rottlerin as a potent immunosuppressive agent for the development of novel therapies in T cell mediated immune disorders.

Acetophenones↗
PubMed2006

The replacement of graft endothelium by recipient-type cells conditions allograft rejection mediated by indirect pathway CD4+ T cells.

BACKGROUND: Whereas the participation of alloreactive T cells sensitized by indirect allorecognition in graft rejection is well documented, the nature of recipient antigen presenting cells recognized by indirect pathway CD4+ T cells within the graft has yet to be identified. The purpose of this study was to determine the role played by graft endothelium replacement in the immune recognition of cardiac allografts rejected by indirect pathway CD4+ T cells. METHODS: Transgenic RAG2-/- mice expressing I-Ab-restricted male antigen H-Y-specific TcR were studied for their capacity to reject H-2k male cardiac allografts. Chronic vascular rejection in this model was due to the indirect recognition of H-Y antigen shed from H-2k male allograft and presented by the recipient's own I-Ab APC to transgenic T cells. RESULTS: Immunohistochemical analysis of rejected grafts revealed the presence of numerous microvascular endothelial cells (EC) that expressed recipient's I-Ab MHC class II molecules. This observation suggested that graft endothelium replacement by I-Ab-positive cells of recipient origin could stimulate the rejection of male H-2k graft by I-Ab-restricted H-Y-specific T cells. To investigate further this possibility, hearts from H-2b-into-H-2k irradiation bone marrow (BM) chimera were transplanted in transgenic recipients. A direct correlation was observed between the presence of I-Ab-positive EC within myocardial microvessels and the induction of acute rejection of chimeric H-2k male cardiac allografts transplanted in transgenic recipients. CONCLUSIONS: We conclude that graft endothelium replacement by recipient-type cells is required for the rejection of cardiac allograft mediated by indirect pathway alloreactive CD4+ T cells.

Amino Acid Sequence↗
PubMed2006

The replacement of graft endothelium by recipient-type cells conditions allograft rejection mediated by indirect pathway CD4(+) T cells.

BACKGROUND: Whereas the participation of alloreactive T cells sensitized by indirect allorecognition in graft rejection is well documented, the nature of recipient antigen presenting cells recognized by indirect pathway CD4(+) T cells within the graft has yet to be identified. The purpose of this study was to determine the role played by graft endothelium replacement in the immune recognition of cardiac allografts rejected by indirect pathway CD4(+) T cells. METHODS: Transgenic RAG2(-/-) mice expressing I-A(b)-restricted male antigen H-Y-specific TcR were studied for their capacity to reject H-2(k) male cardiac allografts. Chronic vascular rejection in this model was due to the indirect recognition of H-Y antigen shed from H-2(k) male allograft and presented by the recipient's own I-A(b) APC to transgenic T cells. RESULTS: Immunohistochemical analysis of rejected grafts revealed the presence of numerous microvascular endothelial cells (EC) that expressed recipient's I-A MHC class II molecules. This observation suggested that graft endothelium replacement by I-A(b)-positive cells of recipient origin could stimulate the rejection of male H-2(k) graft by I-A(b)--restricted H-Y--specific T cells. To investigate further this possibility, hearts from H-2(b)--into--H-2(k) irradiation bone marrow (BM) chimera were transplanted in transgenic recipients. A direct correlation was observed between the presence of I-A(b)-positive EC within myocardial microvessels and the induction of acute rejection of chimeric H-2(k) male cardiac allografts transplanted in transgenic recipients. CONCLUSIONS: We conclude that graft endothelium replacement by recipient-type cells is required for the rejection of cardiac allograft mediated by indirect pathway alloreactive CD4(+) T cells.

Animals↗
PubMed2006

Relation of coronary hypersensitivity to serotonin in cardiac transplant recipients to vessel wall morphology and effect of vitamin C.

Coronary hypersensitivity to serotonin promotes platelet aggregation, entailing the progression of the atherosclerotic process. This abnormality is a common finding in cardiac transplant recipients and may be triggered by reactive oxygen species, which plays a main role in the inflammatory process. Hence, this study aimed to determine the influence of intimal hyperplasia on this abnormality and its reversibility after acute supplementation with the superoxide anion scavenger vitamin C. Therefore, intracoronary injections of serotonin (3 microg), bradykinin (600 ng), and nitroglycerin (isosorbide dinitrate 200 microg) were administered to 21 cardiac transplant recipients (1 year after transplantation) with normal coronary angiographic results; the serotonin injections were repeated after intracoronary vitamin C supplementation (40 mg/min for 14 minutes). In the segments in which serotonin effects were the most pronounced, the diameter changes were measured by quantitative angiography, and vessel wall morphology was studied by intravascular ultrasound (IVUS). The IVUS examination revealed moderate to severe intimal thickening (total area - luminal area/total area) in 9 patients (group 1) of 25 +/- 2%, compatible with the early stage of graft vasculopathy. In this group, hypersensitivity to serotonin remained unchanged after intracoronary vitamin C supplementation, from -21 +/- 3% (percentage from baseline) to -25 +/- 3%, whereas in the other 12 patients with mild intimal thickening (9 +/- 1%; group 2), hypersensitivity to serotonin was attenuated from -20 +/- 5% to -4 +/- 6% (p <0.01). In contrast, the responses to bradykinin and isosorbide dinitrate were similar in the 2 groups. In group 1, plasma levels of high-sensitivity C-reactive protein and proinflammatory cytokines (interleukin-6 and -8) were significantly enhanced. For all the patients studied, the effect of vitamin C on the response to serotonin was significantly correlated with the intimal thickening. In conclusion, at 1 year after transplantation, morphologic changes compatible with the early stage of the graft vasculopathy are accompanied by hypersensitivity to serotonin unresponsive to vitamin C, despite a relatively preserved endothelial function (unaltered response to bradykinin).

Adult↗
PubMed2006

Preferential production of the IL-12(p40)/IL-23(p19) heterodimer by dendritic cells from human newborns.

Human newborns present impaired T helper type 1 cell responses, associated with a defect in the synthesis of IL-12 by dendritic cells (DC). IL-23 is a heterodimeric cytokine structurally related to IL-12, implicated in protective and autoimmune responses. We recently showed that upon activation neonatal T cells up-regulate a functional IL-23 receptor and that this cytokine polarizes the differentiation of naive T cells. We therefore investigated the capacity of neonatal DC to secrete IL-23. Lipopolysaccharide (LPS) stimulation induced the transcription of IL-23(p19) mRNA in both adult and neonatal DC, in sharp contrast to the repressed IL-12(p35) gene expression observed in neonatal cells. In comparison to adult DC, neonatal DC produced similar levels of IL-23 protein, in reponse to Toll-like receptor (TLR)-2- and TLR-3 ligands, and higher levels in response to TLR-4- or TLR-8 ligands. The same profile was observed in neonatal mononuclear cells. The supernatant of LPS-stimulated DC induced the secretion of IL-17 by polyclonally activated neonatal CD8(+) T cells, confirming the IL-23 bioactivity. Altogether, these observations strongly suggest that IL-23 could play a role in the immune system of human newborns. In particular, a functional IL-23/IL-17 axis might compensate a suboptimal IL-12/IFN-gamma pathway in early life.

Adult↗
PubMed2006

Pertussis toxin activates adult and neonatal naive human CD4+ T lymphocytes.

Pertussis toxin (PTX) is known to be mitogenic for T lymphocytes, but its direct action on naive human T cells has not been specified. Herein, we show that PTX induces the proliferation of purified adult CD45RA(+)CD4(+) T cells independently of its ADP-ribosyltransferase activity. PTX directly induces TNF-alpha and IL-2 mRNA expression, modulates the level of several cell surface receptors and induces Forkhead box p3 (Foxp3) protein accumulation in naive CD4(+) T cells. Addition of autologous dendritic cells was found to be required for the production of high levels of IFN-gamma by PTX-stimulated naive T cells. These effects of PTX occurred in conjunction with activation of NF-kappaB and NFAT transcription factors. Overall, responses of neonatal CD4(+) T cells to PTX were similar to those of adult CD45RA(+)CD4(+) naive T cells except for their blunted CD40 ligand up-regulation. We suggest that the adjuvant properties of PTX during primary cell-mediated immune responses involve a direct action on naive T lymphocytes in addition to activation of antigen-presenting cells.

Adult↗
PubMed2006

Early immunosuppression withdrawal after living donor liver transplantation and donor stem cell infusion.

Long-term results of organ transplantation are still limited by serious side effects of immunosuppressive drugs. A major issue, therefore, is to elaborate novel therapeutic protocols allowing withdrawal or minimization of immunosuppressive therapy after transplantation. We report on 3 patients prospectively enrolled in an original protocol designed to promote graft acceptance in living donor liver transplantation, using posttransplant conditioning with high doses of antithymocyte globulin followed by injection of donor-derived stem cells. In 2 patients, early immunosuppression withdrawal was possible, without subsequent graft deterioration. In these 2 cases, in vitro studies showed indices of immunological tolerance as assessed by specific hyporesponsiveness to donor alloantigens in mixed lymphocytes culture. In the third patient, acute rejection rapidly occurred after discontinuation of immunosuppression, and minimal immunosuppression has to be maintained during long-term follow-up. In this case, a clearly distinct immunoreactive profile was observed as compared to tolerant patients, as no specific modulation of the antidonor response was observed in vitro. Of note, no macrochimerism could be detected in any of the 3 patients during the follow-up. In conclusion, these clinical observations demonstrated that, despite the absence of macrochimerism, donor stem cells infusion combined with recipient conditioning may allow early immunosuppression withdrawal or minimization after liver transplantation.

Antilymphocyte Serum↗
PubMed2006

Hypereosinophilic syndrome: lymphoproliferative and myeloproliferative variants.

Idiopathic hypereosinophilic syndrome is a largely heterogeneous disorder defined as persistent, marked hypereosinophilia of unknown origin complicated by end-organ damage. Recent research in cellular and molecular biology has led to the characterization of distinct underlying hematological disorders, primitively involving cells of the myeloid or lymphoid lineage. The ability to classify many hypereosinophilic syndrome patients on the basis of pathogenesis of hypereosinophilia has radically changed therapeutic perspectives. Indeed, imatinib mesylate has become first-line therapy for patients in whom the FIP1L1-PDGFRalpha fusion gene is detected, whereas corticosteroids remain the mainstay for management of patients in whom hypereosinophilia is secondary to the overproduction of interleukin 5 by abnormal T-cells. Use of monoclonal anti-interleukin-5 antibodies in the latter group of patients has a strong rationale and could decrease cumulative corticosteroid doses and toxicity. As far as prognosis of these disease variants is concerned, hypereosinophilic syndrome patients with the FIP1L1-PDGFRalpha fusion gene may develop acute myelogenous (eosinophilic) leukemia, whereas those with clonal interleukin-5-producing T-cells have an increased risk of developing T-cell lymphoma. It is currently unclear whether timely therapeutic intervention in such patients could interfere with long-term progression toward malignant hematological disorders.

Antibodies, Monoclonal↗
PubMed2005

IL-4 deficiency prevents eosinophilic rejection and uncovers a role for neutrophils in the rejection of MHC class II disparate skin grafts.

BACKGROUND: Acute rejection of MHC class II-disparate bm12 skin grafts by C57BL/6 recipient mice is characterized by massive graft infiltration by eosinophils, together with increased intragraft amounts of IL-4 and IL-5 mRNA. IL-5 blockade prevents the intragraft eosinophil infiltration and prolongs the survival of skin allografts. As the differentiation of T cell precursors into Th2 cells is largely driven by IL-4, we investigated the role of IL-4 in MHC class II-disparate allograft rejection. METHODS: We performed skin grafts from MHC class II incompatible bm12 mice into wild-type C57BL/6 mice (IL-4) or C57BL/6 IL-4 deficient mice (IL-4). Graft survival, in vitro T cell reactivity, and histology were compared. RESULTS: We observed that 50% of IL-4 mice rapidly rejected their bm12 allograft, whereas the other 50% retained their graft 60 days after transplantation. Histological examination of bm12 allografts retained by IL-4 mice showed a normal appearance with no inflammatory infiltrate and no eosinophils. Among IL-4 mice that acutely rejected their bm12 skin graft, we observed a dense polymorphonuclear infiltrate. The depletion of neutrophils significantly prolonged bm12 graft survival. CONCLUSIONS: Eosinophil infiltrates, typical of MHC class II disparate acute skin graft rejection, are critically dependent on the availability of IL-4. IL-4 mice reject MHC class II disparate skin grafts by a pathway of rejection where neutrophils play a direct causal role.

Animals↗
PubMed2005

Regulatory role of host CD8+ T lymphocytes in experimental graft-versus-host disease across a single major histocompatibility complex class II incompatibility.

BACKGROUND: CD8+ T cells are known to regulate type 2 helper T cell (Th2) alloreactive immune responses but their mode of activation is unclear. We investigated the role of host CD8+ T cells in experimental Th2-type graft-versus-host disease (GVHD) where donor/recipient disparity is restricted to a single major histocompatibility complex (MHC) class II antigen. METHODS: Immunoglobulin (Ig) E serum levels, eosinophilia and lymphoid tissue hyperplasia were compared after injection of bm12 CD4+ T cells in either wild-type or CD8+ T cell-deficient (CD8-/-) C57BL/6 mice. In vitro, we explored effects of the addition of CD8+ T cells from wild-type or IFN-gamma-/- mice in mixed leukocyte cultures prepared with beta2 microglobulin-deficient (beta2m-/-) CD4+ T cells as responders or beta2m dendritic cells as stimulators. RESULTS: HyperIgE resolved after 3 weeks in wild-type hosts whereas it persisted for 6 weeks in CD8-/- hosts. Eosinophil infiltrates in lymph nodes were significantly enhanced in CD8-/- hosts. Increased serum levels of IL-5 and IL-13 in CD8-/- hosts confirmed the enhancement of Th2-type responses in the context of recipient CD8+ T cell deficiency. Hyperplasia of lymph nodes and spleen were similar in both groups, as well as in vivo proliferation of donor CD4+ T cells. In vitro, CD8+ T cell regulation of the alloreactive Th2 response depended on their production of IFN-gamma and did not require expression of beta2m on CD4+ T cells or antigen-presenting cells. CONCLUSIONS: Host CD8+ T cells regulate alloreactive Th2 responses during graft-versus-host disease through an IFN-gamma dependent pathway, independently of the recognition of beta2m-associated MHC class I molecules.

Animals↗
PubMed2005

Myocardial homing of nonmobilized peripheral-blood CD34+ cells after intracoronary injection.

Granulocyte--colony-stimulating factor administered for autologous hematopoietic stem cell isolation from blood may favor restenosis in patients implanted after acute myocardial infarction (AMI). We therefore tested the isolation of peripheral-blood CD34+ cells without mobilization in six patients with AMI. After large-volume cytapheresis and positive CD34+ cell selection, 3.6 to 27.6 million CD34+ cells were obtained. We performed intra-coronary implantation of these cells and recorded no restenosis or arrhythmia. We used positron emission tomography (PET) to assess myocardial-labeled CD34+ cell homing, which accounted for 5.5% of injected cells 1 hour after implantation. In conclusion, large amounts of CD34+ cells, in the range reported in previous studies, can be obtained from nonmobilized peripheral blood. PET with [18F]-fluorodeoxyglucose cell labeling is an efficient imaging method for homing assessment.

Adult↗
PubMed2005

Interferon regulatory factor 3 is involved in Toll-like receptor 4 (TLR4)- and TLR3-induced IL-12p35 gene activation.

Interleukin-12 (IL-12) is a heterodimeric cytokine produced by dendritic cells (DCs) in response to Toll-like receptor (TLR) ligation. While the mechanisms regulating IL-12p40 chain gene expression are well characterized, molecular events involved in IL-12p35 chain gene activation remain to be clarified. Since IL-12p35 mRNA was induced in human DCs activated through TLR3 or TLR4 but not TLR2, we investigated the potential role of interferon regulatory factor 3 (IRF-3) in IL-12p35 gene transactivation. First, a binding site for IRF-3 named interferon-stimulated response element-1 (ISRE-1) was identified in the human IL-12p35 promoter region between nucleotides -251 and -240. The ISRE-1 site was required for IL-12p35 gene activation in RAW 264.7 cells stimulated by lipopolysaccharide (LPS) or PolyI:C. Ectopic expression of IRF-3 was found to up-regulate IL-12p35 gene activation in the same system. Furthermore, chromatin immunoprecipitation (ChIP) studies demonstrated that IRF-3 is recruited to ISRE-1 site in TLR4- or TLR3-stimulated human DCs. Finally, experiments on DCs from IRF-3-deficient mice established that TLR4-induced IL-12p35 mRNA and IL-12p70 synthesis are impaired in absence of IRF-3. We conclude that IRF-3 binds to a critical cis-acting element in the IL-12p35 gene promoter and thereby represents a key factor for the induction of IL-12p70 synthesis in DCs.

Animals↗
PubMed2005

IL-4 and IL-13 mRNA real-time PCR quantification on whole blood to assess allergic response.

Although routinely used in clinical practice, skin prick tests and serum specific IgE often fail to distinguish between IgE-sensitization and symptomatic IgE-mediated allergy. There is therefore a need for new laboratory tests relating allergic symptoms to the offending agent. In this way, we evaluated the diagnostic reliability of a new whole blood quantitative real-time PCR assay for IL-4 and IL-13 mRNAs. We compared the response of cat allergic patients and non-cat allergic controls upon anti-IgE and cat allergen (Fel d1) stimulation of whole blood. Allergen addition led to a significant increase of IL-4 and IL-13 mRNAs in allergic patients compared to non-allergic controls (p<0.0001). Both cytokine mRNA levels were strongly correlated and peaked within 2 h after Fel d1 or anti-IgE addition. This rapid increase as well as purification experiments led us to the conclusion that basophils represent an important if not the main source of both transcripts in this setting. The effect was allergen-specific since not observed when stimulating blood from cat allergic patients with birch pollen. Interestingly, we found that IFN-gamma mRNA, contrary to IL-4 mRNA, reached higher levels in response to Fel d1 with control individuals than with patients allergic to cat. This study shows that whole blood real-time PCR is a valuable method for IL-4 and IL-13 mRNA measurement after in vitro allergen challenge. We suggest that it might be useful, complementing conventional markers, for the diagnosis and the follow-up of allergic diseases. Further assessments are required to evaluate the clinical potential of this technique.

Adult↗
PubMed2005

Thrombospondin-1 and indoleamine 2,3-dioxygenase are major targets of extracellular ATP in human dendritic cells.

Extracellular adenosine triphosphate affects the maturation of human monocyte-derived dendritic cells (DCs), mainly by inhibiting T-helper 1 (Th1) cytokines, promoting Th2 cytokines, and modulating the expression of costimulatory molecules. In this study, we report that adenosine triphosphate (ATP) can induce immunosuppression through its action on DCs, defining a new role for extracellular nucleotides. Microarray analysis of ATP-stimulated human DCs revealed inter alia a drastic up-regulation of 2 genes encoding mediators involved in immunosuppression: thrombospondin-1 (TSP-1) and indoleamine 2,3-dioxygenase (IDO). The release of TSP-1 by DCs in response to ATP was confirmed at the protein level by enzyme-linked immunosorbent assay (ELISA), immunodetection, and mass spectrometry analysis, and has an antiproliferative effect on T CD4+ lymphocytes through TSP-1/CD47 interaction. Our pharmacologic data support the involvement of purinergic receptor P2Y11 in this ATP-mediated TSP-1 secretion. We demonstrate also that ATP significantly potentiates the up-regulation of IDO--a negative regulator of T lymphocyte proliferation--and kynurenine production initiated by interferon-gamma (IFN-gamma) in human DCs. Thus, extracellular ATP released from damaged cells and previously considered as a danger signal is also a potent regulator of mediators playing key roles in immune tolerance. Consequently, nucleotides' derivatives may be considered as useful tools for DC-based immunotherapies.

Adenosine Triphosphate↗
PubMed2005

A new dendritic cell vaccine generated with interleukin-3 and interferon-beta induces CD8+ T cell responses against NA17-A2 tumor peptide in melanoma patients.

Dendritic cells derived from monocytes cultured in the presence of type I interferon were found to induce efficient T cell responses against tumor antigens in vitro. We vaccinated eight stage III or IV melanoma patients with dendritic cells generated with interferon-beta and interleukin-3, activated by poly I: C, and pulsed with the tumor-specific antigen NA17.A2. This dendritic cell vaccine was well-tolerated with only minor and transient flu-like symptoms and inflammatory reactions at the injection sites. In most patients, isotopic imaging documented dendritic cells (DC) migration from the intradermal injection site to the draining lymph nodes. Finally, mixed lymphocyte-peptide culture under limiting dilution conditions followed by tetramer labeling indicated that three out of eight patients mounted a CD8 T cell response against the NA17.A2 antigenic peptide. We conclude that DC generated in type I-IFN represent an interesting alternative to DC generated in IL-4 and GM-CSF for cancer immunotherapy.

Adult↗