Showing papers by "Wolf H. Fridman published in 2001"
TL;DR: In this paper, the crystal structure of a human Fc receptor (FcgammaRIIIB) in complex with an Fc fragment of human IgG1 determined from orthorhombic and hexagonal crystal forms at 3.0-and 3.5-A resolution, respectively.
393 citations
TL;DR: The detection and cytokine modulation of FcγRIIb2 in human myeloid cells provide evidence of a negative regulator of immune complex-mediated responses in human phagocytes and offer a new approach to limit Ab-triggered inflammation in autoimmune disease.
Abstract: Immune complex-mediated inflammatory responses are initiated by Fc gamma R on phagocytes. We report in this study that an inhibitory receptor, Fc gamma RIIb2, is expressed on circulating human monocytes, and when co-cross-linked with stimulatory Fc gamma R it down-regulates effector function. Fc gamma RIIb2 expression is increased by IL-4 and decreased by IFN-gamma, in contrast to the activating receptor, Fc gamma RIIa, which is increased by IFN-gamma and decreased by IL-4. Thus, Th1 and Th2 cytokines differentially regulate the opposing Fc gamma R systems, altering the balance of activating and inhibiting Fc gamma R. The detection and cytokine modulation of Fc gamma RIIb2 in human myeloid cells provide evidence of a negative regulator of immune complex-mediated responses in human phagocytes and offer a new approach to limit Ab-triggered inflammation in autoimmune disease.
257 citations
TL;DR: The genetic defect of a selective and complete C1s deficiency in a Caucasian patient with complex autoimmune diseases is characterized for the first time.
Abstract: We have investigated the molecular basis of selective and complete C1s deficiency in 2-year-old girl with complex autoimmune diseases including lupus-like syndrome, Hashimoto’s thyroiditis, and autoimmune hepatitis. This patient’s complement profile was characterized by the absence of CH50 activity, C1 functional activity
61 citations
TL;DR: It is suggested that serum sIL-2Ralpha could be considered as an independent serum biomarker in head and neck cancer patients and less likely to develop distant metastasis during the 36 months follow up.
55 citations
TL;DR: The results suggest that the recruitment of LC at epithelial surface might be suppressed during Th1 and Th2 immune responses, and amplified during regulatory immune responses involving IL-10 and TGF-β.
Abstract: Immune responses are initiated by dendritic cells (DC) that form a network comprising different populations. In particular, Langerhans cells (LC) appear as a unique population of cells colonizing epithelial surfaces. We have recently shown that macrophage-inflammatory protein-3α/CCL20, a chemokine secreted by epithelial cells, induces the selective migration of LC among DC populations. In this study, we investigated the effects of cytokines on the expression of the CCL20 receptor, CCR6, during differentiation of LC. We found that both IL-4 and IFN-γ blocked the expression of CCR6 and CCL20 responsiveness at different stages of LC development. The effect of IL-4 was reversible and most likely due to the transient blockade of LC differentiation. In contrast, IFN-γ-induced CCR6 loss was irreversible and was concomitant to the induction of DC maturation. When other cytokines involved in DC and T cell differentiation were tested, we found that IL-10, unlike IL-4 and IFN-γ, maintained CCR6 expression. The effect of IL-10 was reversible and upon IL-10 withdrawn, CCR6 was lost concomitantly to final LC differentiation. In addition, IL-10 induced the expression of CCR6 and responsiveness to CCL20 in differentiated monocytes that preserve their ability to differentiate into mature DC. Finally, TGF-β, which induces LC differentiation, did not alter early CCR6 expression, but triggered its irreversible down-regulation, in parallel to terminal LC differentiation. Taken together, these results suggest that the recruitment of LC at epithelial surface might be suppressed during Th1 and Th2 immune responses, and amplified during regulatory immune responses involving IL-10 and TGF-β.
48 citations
TL;DR: FcγRIIB phosphorylation may not be sufficient in vivo to enable the recruitment of SHP-1 but that (pathological?) conditions that would hyperphosphorylate FcγrIIB might enable SHp-1 recruitment.
45 citations
TL;DR: Decysin represents the first marker for this previously unrecognized cell population of the mouse spleen, which may represent a precursor for GCDC and may be specialized in the transport of unprocessed Ag from the MZ into developing GC.
Abstract: Decysin, a gene encoding a disintegrin metalloprotease, is transcribed in human dendritic cells (DC) and germinal centers (GC). We have cloned its murine homologue and show that it is processed by the endoprotease furin before secretion of the catalytic domain. We have defined the cell types that express decysin in mouse spleen in the course of an immune response to T cell-dependent Ags. Like in humans, decysin is transcribed by activated CD11c + DC that enter the T cell zone from the marginal zone (MZ). In the GC, decysin is expressed by follicular DC and tingible body macrophages. In addition, a MZ cell population expresses decysin and appears to migrate into the B cell follicle. The majority of these follicle-homing cells express the mannose receptor ligand, a marker for the macrophage-like MZ metallophils. The follicle-homing cells are M-CSF dependent, as they are absent in op/op mice that lack functional M-CSF. This suggests that mannose receptor ligand + MZ metallophils differentiate into cells that migrate from the MZ into the B cell follicle. Decysin represents the first marker for this previously unrecognized cell population of the mouse spleen, which may represent a precursor for GCDC and may be specialized in the transport of unprocessed Ag from the MZ into developing GC.
38 citations
TL;DR: The results demonstrate that FcγRIIB use SHIP1 to inhibit pathways shared by receptor tyrosine kinases and immunoreceptors to trigger cell proliferation and cell activation, respectively, but that, in the absence ofSHIP1, F cγR IIB can use other effectors that specifically inhibit cell proliferation.
37 citations
TL;DR: It is demonstrated that soluble CD16 (sCD16; soluble FcγRIII), a natural ligand of CR3, inhibits the infection of monocytes by primary R5 HIV-1 strain opsonized with serum of seronegative individuals, and it is observed that the concentration of sCD16 is greatly decreased in sera of HIV-infected patients with low lymphocyte CD4+ counts.
Abstract: We demonstrate that soluble CD16 (sCD16; soluble Fc gamma RIII), a natural ligand of CR3, inhibits the infection of monocytes by primary R5 HIV-1 strain opsonized with serum of seronegative individuals. Inhibition of monocyte infection by sCD16 was similar to that observed with anti-CR3 mAbs, indicating that opsonized HIV may use a CR3-dependent pathway for entry in monocytic cells. Cultured human monocytes express both CR3 (CD11b/CD18) and CCR5 receptors. RANTES, the natural ligand of CCR5, inhibited infection of monocytes with unopsonized HIV particles and partially that of monocytes infected with HIV particles opsonized with complement-derived fragments. Although HIV-infected monocytes from homozygous CCR5 Delta 32/Delta 32 (CCR5(-/-)) individuals produce low levels of p24, cells infected with opsonized particles produced higher levels of p24 than cells infected with unopsonized particles. Our results thus suggest that CR3 may represent an alternative coreceptor to CCR5 of opsonized primary R5 virus entry into monocytes/macrophages. We also observed that the concentration of sCD16 is greatly decreased in sera of HIV-infected patients with low lymphocyte CD4(+) counts. Taken together, our findings suggest that sCD16, present in plasma, may play an important role in controlling HIV-1 spread.
35 citations
Journal Article•
TL;DR: Increased IL-18 production in chronic CD lesions is shown and epithelial cells and macrophages are identified as IL- 18-producing cells and these results are in accordance with a putative role of matureIL-18 in the pathogenesis of CD.
Abstract: A local increase of interleukin-18 (IL-18) expression has been recently demonstrated in Crohn's disease (CD), suggesting a role for mature IL-18 (cleaved by ICE protease) in the induction of proinflammatory cytokines and Th1 polarization observed in CD lesions. The aim of this study was to investigate IL-18 modulation and its potential immune consequences in CD lesions. We showed increased IL-18 production in chronic CD lesions and identified epithelial cells and macrophages as IL-18-producing cells. A twofold increase in ICE alpha, beta, and/or gamma mRNA that encodes for the complete mature peptide was required for ICE activity, and a marked increase in IL-18R-positive immune cells was observed in chronic lesions compared to uninvolved areas or normal control samples. Chronic lesions also displayed intense transcription of IL-18-induced cytokines, IFN-gamma, IL-1beta, TNF-alpha, and IL-8. By contrast, when neither IL-18 nor ICE mRNAs were enhanced (early asymptomatic CD lesions), IL-18-induced cytokines were not up-regulated. These results are in accordance with a putative role of mature IL-18 in the pathogenesis of CD.
29 citations
TL;DR: In vivo Winn tests performed in SCID mice showed that the expression of anti-CD16 scFv on tumor cells, but not of the negative control anti-phOx scFV, prevented tumor cell growth, representing a novel and potent antibody-based gene therapy approach, which may have clinical applications in cancer therapy.
Abstract: We have developed a novel immunostimulatory molecule against tumor cells, composed of an anti-FcgammaRIII (CD16) scFv fused to the platelet-derived growth factor receptor (PDGFR) transmembrane region. This fusion molecule was stably expressed on the tumor cell surface and retained the ability of the parental antibody to bind soluble CD16. Tumor cells expressing anti-CD16 scFv triggered the release of IL-2 by Jurkat-CD 16/gamma cells and of TNFalpha by monocytes when co-cultured with these cells. Furthermore, NK cells could kill scFv-transfected HLA+ class I H1299 lung carcinoma tumor cells, but not the parental cells, indicating that anti-CD16 scFv tumor expression prevents the killer inhibitory receptor (KIR)-mediated inhibition of NK cell cytotoxicity. This anti-CD16 scFv tumor expression also enhanced tumor phagocytosis by IFNgamma-activated macrophages, a mechanism known to induce a protective long-term adaptative immunity to tumors. In vivo Winn tests performed in SCID mice showed that the expression of anti-CD16 scFv on tumor cells, but not of the negative control anti-phOx scFv, prevented tumor cell growth. Thus, expression of FcR antibodies or other FcR-specific ligands on tumor cells represents a novel and potent antibody-based gene therapy approach, which may have clinical applications in cancer
TL;DR: Allogeneic mixed lymphocyte reactions (MLR) showed that MAKs are poor stimulatory cells compared with MAC–DCs, while MAK should be primarily used as effector killer cells.
Abstract: Clinical grade ex vivo-generated antigen-presenting cells, macrophage–dendritic cells (MAC–DCs) or macrophage-activated killers (MAKs) were derived from peripheral blood mononuclear cells (PBMCs). Cultures (7 d) were performed in non-adherent conditions in the presence of granulocyte–macrophage colony-stimulating factor (GM-CSF) and either interleukin 13 (IL-13) or dihydroxy-vitamin D3 respectively. MAKs were activated during the last 24 h with interferon γ (IFNγ). Reverse transcription polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) analyses indicated that IL-1β and tumour necrosis factor α (TNFα) were produced by both cells. Higher pro-inflammatory cytokine (IL-1β and TNFα) amounts were detected on average in MAK supernatants. In contrast, IL-12 p40 was found only in MAC–DC supernatants, but the biologically active IL-12 form (p70) was never detected. T-cell cytokines (IL-2, IL-4, IL-10) were not produced in culture conditions in which T cells were nevertheless present. At d 7, TNFα or lipopolysaccharide (LPS) upregulated IL-12 p40 production by MAC–DCs, while IL-12 p70 remained undetectable. LPS stimulation also increased TNFα production by these cells. Allogeneic mixed lymphocyte reactions (MLR) showed that MAKs are poor stimulatory cells compared with MAC–DCs. The MAC–DC stimulatory capacity was enhanced by LPS, although the expression of HLA class II, CD83, CD80 and CD86 was unmodified. Thus, MAC–DCs represent a tool for triggering adaptative immunity, while MAK should be primarily used as effector killer cells.
TL;DR: A method is set up which allows to purify functional human recombinant FcγRIIa2 for further characterization of its biological activities and a specific binding of the purified recombinant molecule to surface IgG expressed by human B cells is demonstrated.
Abstract: The present study describes the methodology used to purify human recombinant low-affinity FcγRIIa2 produced in E. coli and to evaluate its binding to surface IgG. The recombinant molecule was purified by a two-step chromatographic procedure, including affinity chromatography using IV.3 anti-FcγRIIa1/2 immunosorbent, followed by gel filtration chromatography. Using this method, the purified recombinant FcγRIIa2 was 99% pure. It exhibited an isoeletric point of 5.2. Binding studies demonstrated a specific binding of the purified recombinant molecule to surface IgG expressed by human B cells. Thus, we have set up a method which allows to purify functional human recombinant FcγRIIa2 for further characterization of its biological activities. *Work for which these authors equally contributed.
01 Jan 2001
TL;DR: The present review discusses recent findings that shed the molecular bases for the affinity of the FcyRIIB ITIM for SHIPs, that explained why SHips, rather than SH2 domain-containing protein tyrosine phosphatases, are recruited by F CyRITB in vivo, and that unraveled a dual mechani sm used by Fcy RIIB to negatively regulate B cell activation via SHIPI.
Abstract: The intracytoplasmic domain of FcγRIIB, a family of widely expressed IgG receptors, contains an Immunoreceptor Tyrosine-based Inhibition Motif (ITIM) that accounts for the ability of these receptors to negatively regulate cell activation and cell proliferation induced by receptors containing Immunoreceptor Tyrosine-based Activation Motif (ITAMs) and by receptors with an intrinsic protein tyrosine kinase activity. These properties lie in the affinity of the FcγRIIB ITIM for SH2 domain-containing inositol 5-phosphatases (SHIPs). FcγRIIB are the only known ITIM-bearing receptors capable of recruiting SHIPs in vivo. The present review discusses recent findings that established the molecular bases for the affinity of the FcγRIIB ITIM for SHIPs, that explained why SHIPs, rather than SH2 domain-containing protein tyrosine phosphatases, are recruited by FcγRIIB in vivo, that unraveled a dual mechanism used by FcγRIIB to negatively regulate B cell activation via SHIP1, and that demonstrated the role of SHIP1 in FcγRIIB-dependent negative regulation of mast cell proliferation induced by the growth factor receptor Kit.