aimé vazquez - Academia.edu (original) (raw)
Papers by aimé vazquez
Journal of Immunology, Jun 15, 1991
Differential regulation of surface Ig-and Lyb2-mediated B cell activation by cyclic AMP. I. Evide... more Differential regulation of surface Ig-and Lyb2-mediated B cell activation by cyclic AMP. I. Evidence for alternative regulation of signaling through two different receptors linked to phosphatidylinositol hydrolysis in murine B cells.
Cell Death & Differentiation, Jun 22, 2007
Heavy metals are important regulators of cell apoptosis. Manganese (Mn 2 þ) is a potent inducer o... more Heavy metals are important regulators of cell apoptosis. Manganese (Mn 2 þ) is a potent inducer of apoptosis in different cell types, but the precise mechanisms that mediate such effects are not well defined. We previously reported that Mn 2 þ was a potent apoptotic agent in human B cells, including lymphoma B cell lines. We show here that Mn 2 þ-induced cell death in human B cells is associated with caspase-8-dependent mitochondrial activation leading to caspase-3 activity and apoptosis. We used specific caspase-8 interfering shRNAs to reduce caspase-8 expression, and this also reduced Mn 2 þ-induced caspase-3 activation and apoptosis. Mn 2 þ-triggered caspase-8 activation is associated with a specific pathway, which is independent of Fas-associated death domain protein, and dependent on the sequential activation of p38-mitogen-activated protein kinase (p38 MAPK) and mitogen-and stress-response kinase 1 (MSK1). Inhibition of p38 activity using either pharmacological inhibitors or dominant-negative mutant forms of p38 blocked Mn 2 þ-mediated phosphorylation of MSK1 and blocked subsequent caspase-8 activation. However, specific inhibitors and the expression of a dominant-interfering mutant of MSK1 only inhibited caspase-8 activation, but not p38 activity. These findings suggest a novel model for the regulation of caspase-8 during Mn 2 þ-induced apoptosis based on the sequential activation of p38 MAPK, MSK1, caspase-8 and mitochondria, respectively.
Journal of Immunology, 1989
Biochemical and physicochemical characterization of mouse B cell growth factor: a lymphokine dist... more Biochemical and physicochemical characterization of mouse B cell growth factor: a lymphokine distinct from interleukin 2.
Journal of Immunology, Apr 1, 1997
IL-4 activates resting B cells and, in conjunction with cosignals such as anti-IgM (anti-mu) Ab o... more IL-4 activates resting B cells and, in conjunction with cosignals such as anti-IgM (anti-mu) Ab or CD40 ligand, modulates progression of B cells through the cell cycle, leading to proliferation. In this study, we show that the mitogenic combination of IL-4 and anti-mu Ab triggered induction of cyclin D3 and up-regulated cyclin-dependent kinase (cdk) 6 expression, whereas such regulation was not observed in B cells activated by IL-4 or anti-mu Ab alone. Furthermore, cyclin D3 immunoprecipitated fron as associated with cdk6, and the cyclin D3/cdk6 complex was able to phosphorylate recombinant retinoblastoma protein in vitro. In addition, B cells activated with either IL-4 or 1L-13 alone expressed a higher amount of p27kip1 (p27) cdk inhibitor than nonstimulated cells. In contrast, p27 expression was decreased when cells were activated with mitogenic combinations of IL-4 and anti-mu Ab or anti-CD40 mAb. We also observed that the IL-4-mediated inhibition of the proliferation of anti-mu/IL-2- or anti-mu/phorbol 12,13-dibutyrate-activated human leukemic B cells was associated with the maintenance of large amounts of p27 in these cells. These data suggest that IL-4 controls B cell proliferation by action during at least two steps of the regulation of the cell cycle, cyclin D3/cdk6 complex regulation and p27 inhibitor expression.
The Journal of Immunology
Engagement of the B cell Ag receptor can induce a suicide pathway in various B cell types. Earlie... more Engagement of the B cell Ag receptor can induce a suicide pathway in various B cell types. Earlier studies showed that anti-IgM mAb treatment triggers apoptotic death in the Burkitt lymphoma-derived cell line, Ramos. We show that two B cell surface molecules, CD19 and CD22, which have been reported to interact either functionally or structurally with the B cell Ag receptor, also stimulate cell suicide when sufficiently aggregated, both in the Ramos and EBV-infected Ramos AW cell lines. In conditions of lower cross-linking, both molecules enhance the apoptotic response induced by a suboptimal dose of anti-IgM mAb in Ramos cells, reinforcing the notion that CD19 and CD22 may be involved in the death pathway and modulate Ag-induced B cell apoptosis. Similar outcomes were obtained with human tonsillar B cells, which enter the death program upon treatment with cross-linked anti-IgM, -CD19, or -CD22 mAbs. These results indicate that Ag-induced B cell suicide may affect mature B cells in t...
The Journal of Immunology
The addition of monoclonal antibodies against the human C3b/C4b receptor (CR1) to cultures of per... more The addition of monoclonal antibodies against the human C3b/C4b receptor (CR1) to cultures of peripheral blood lymphocytes in the presence of suboptimal amounts of TNP bound to polyacrylamide beads enhanced by 150 to 400% the specific anti-TNP response, as measured by a plaque-forming cell assay on day 7. Anti-CR1 antibodies similarly enhanced the anti-fluorescein antibody response. Enhancement only occurred in cultures performed in the presence of the relevant antigen. No enhancing effect on the anti-TNP response was observed on addition to cultures of monoclonal antibodies directed against other surface antigens of B cells or an anti-T cell antibody of the same subclass as that of anti-CR1 antibodies. Anti-CR1 antibodies alone did not induce nonspecific B cell proliferation and did not provide B cells with a first signal for proliferation in the presence of a source of B cell growth factors. Anti-CR1 antibodies did not enhance the nonspecific proliferative response of B cells to g...
Blood, 1996
Human interleukin-13 (IL-13) acts at different stages of the normal B- cell maturation pathway wi... more Human interleukin-13 (IL-13) acts at different stages of the normal B- cell maturation pathway with a spectrum of biologic activities overlapping those of IL-4. B chronic lymphocytic leukemia (B-CLL) is characterized by the accumulation of slow-dividing and long-lived monoclonal B cells, arrested at the intermediate stage of their differentiation. In vitro, B-CLL cells exhibit a spontaneous apoptosis regulated by different cytokines. In this report, we show that IL-13 (10 to 200 ng/mL) acts directly on monoclonal B-CLL cells from 12 patients. (1) IL-13 enhances CD23 expression and induces soluble CD23 secretion by B-CLL cells but does not exhibit a growth factor activity. (2) IL-13 inhibits IL-2 responsiveness of B-CLL cells, activated either with IL-2 alone or through crosslinking of lgs or ligation of CD40 antigen. (3) IL-13 protects B-CLL cells from in vitro spontaneous apoptosis. The effects of IL-13 on neoplasic B cells were slightly less than those of IL-4 and occurred indepen...
Http Www Theses Fr, Oct 10, 2013
, that willingly participated in the evaluation of my work during my thesis. George Thyphronitis,... more , that willingly participated in the evaluation of my work during my thesis. George Thyphronitis, for encouraging me to move to France for an internship during my studies. Aimé Vazquez, for the warm welcome and his constant support since my first year in France. Nicolas Bidère, for an excellent cooperation and everyday presence and availability during my thesis.
Néphrologie & Thérapeutique, 2014
Introduction De nombreux arguments cliniques et experimentaux suggerent qu’un dysfonctionnement d... more Introduction De nombreux arguments cliniques et experimentaux suggerent qu’un dysfonctionnement du systeme immunitaire serait associe a la recidive de hyalinose segmentaire et focal (HSF). Nous avons identifie que CASK (calcium/calmodulin-dependent serine protein kinase) est presente dans le serum des patients et agit comme un facteur de permeabilite. Nous avons cherche si CASK pourrait etre exprimee dans les PBMC (cellules mononucleaires de sang peripherique) des patients. Patients et methodes Nous avons etudie l’expression de CASK dans les PBMC des patients (HSF, diabetique ayant syndrome nephrotique et sujet sain) par cytometrie en flux et dans plusieurs types de cellules hematopoietiques en immunoblot. Discussion et conclusion Nous avons observe que CASK est principalement exprimee par des cellules CD14+ (25 % ± 3 %) et dans une fraction plus faible des lymphocytes T (3 % ± 4 %) et des lymphocytes B (4 % ± 4,5 %) chez les patients atteints HSF. Elle n’est detectee ni chez les sujets sains ni chez les sujets ayant une nephropathie diabetique. L’expression de CASK est egalement detectee dans les lignees lymphocytaires KMH2 (cellule de Lymphome de Hodgkin) et Jurkat (leucemie des lymphocytes T). Dans les cultures primaires nous avons observe l’expression de CASK dans une sous-population de macrophage ayant une polarite du type M2 in vitro. Cette sous-population est caracterisee par un phenotype CD163 (Scavenger receptor) et CD206 (Mannose receptor C type 1) et joue un role dans la reparation tissulaire et l’angiogenese. Nos resultats suggerent qu’une expression/regulation aberrante de CASK pourrait etre generee dans un contexte inflammatoire par des monocytes/macrophages des patients atteints de HSF. La polarisation des macrophages in vitro nous permettra de comprendre le mecanisme de la regulation de la synthese de CASK.
The Journal of Immunology
We previously reported that p56lck expression is upregulated in human B lymphocytes upon mitogeni... more We previously reported that p56lck expression is upregulated in human B lymphocytes upon mitogenic stimulation. In this report, we characterized the molecules associated with p56lck in vivo in leukemic B cells costimulated with anti-mu Ab and IL-2 for 72 h. In vitro phosphorylation after p56lck immunoprecipitation indicated that p56lck is associated in vivo with the beta chain of the IL-2 receptor and p42 MAP kinase as well as a number of other proteins. Moreover, p56lck-associated MAP kinase is tyrosine and threonine phosphorylated, suggesting that it is activated. Prevention of DNA synthesis with aphidicolin abrogated this molecular association, and furthermore, cell cycle analysis with IL-2-dependent T cells showed that in cells in G1, MAP kinase was not associated to p56lck, whereas this p56lck-MAP kinase association was observed when cells are in S phase. Thus, p56lck and MAP kinase are only associated during S phase. These data suggest that MAP kinase in association with p56lc...
Transfection of MEFs with poly(I:C) triggers TBK1 accumulation at the centrosome at late time poi... more Transfection of MEFs with poly(I:C) triggers TBK1 accumulation at the centrosome at late time points. (A) MEFs were either left untreated (MOCK) or transfected with LMW poly(I:C) (5 μg/mL) for 4 h (trPoly(I:C)). TBK1 staining was then analyzed by immunofluorescence. The Golgi apparatus was labeled with an antibody against GM130, whereas TBK1 was detected with a rabbit monoclonal antibody. Scale bars, 10 μm. (B–E) MEFs were either left untreated (MOCK) or transfected with HMW poly(I:C) (5 μg/mL) for 4 h (trPoly(I:C)). The indicated proteins were analyzed by immunofluorescence staining with specific antibodies. The Golgi apparatus was labeled with an antibody against GM130, whereas centrosomes were labeled with an antibody against pericentrin. Scale bars, 10 μm. On the right, enlargement of the framed zone in the overlay. (PDF 1624 kb)
OPTN silencing impairs IRF3 signaling after RLR or TLR3 activation. (A) HEK293T cells were transf... more OPTN silencing impairs IRF3 signaling after RLR or TLR3 activation. (A) HEK293T cells were transfected with a control nonspecific siRNA (NS) or with five individual OPTNspecific siRNAs (OPTN A, B, C, D and E) or a NEMO-specific siRNA. The cells were then transfected, 48 h later, with an IFNβ promoter reporter or with a NF-κB reporter and the Renilla luciferase gene as an internal control. Then, 24 h after transfection, cells were either left unstimulated (Unstim) or infected with Sendai virus (+SeV) for 7 h. Luciferase assays were performed and the results were normalized against Renilla luciferase activity. The data shown are means ± SD from three independent experiments (analysis of variance and comparison with NS siRNA-transfected cells in Student's t-test). RLU, relative luminescence units. ns, not significant. (B) HEK293T cells were transfected with a control nonspecific siRNA (NS) or with two individual OPTN-specific siRNAs (OPTN A and OPTN B) or a NEMO-specific siRNA. The...
Cancer research, Jan 15, 1987
Using in vitro-growing myeloma cell lines, we studied the growth factors involved in human multip... more Using in vitro-growing myeloma cell lines, we studied the growth factors involved in human multiple myeloma, and particularly the potential of autocrine secretion and response to B-cell growth factor (BCGF) of RPMI 8226, the best-documented Epstein-Barr virus-negative human myeloma cell line. We found that three myeloma cell lines (RPMI 8226, U266, and IM9) produce an autostimulatory growth factor (AGF) and thus increase their own proliferation by 2- to 3-fold in cells cultured at low density. Optimal AGF production was obtained after 24 h of culture at a cell density ranging from 2.5 to 5 million cells/ml. The three myeloma cell lines produce type II BCGF, able to induce the proliferation of highly purified human peripheral blood B-cells, only after anti-mu activation. The BCGF produced by RPMI 8226 can be absorbed onto RPMI 8226 cells together with the RPMI 8226 AGF, and the two are copurified on gel filtration in a peak with an apparent molecular weight of 70,000. RPMI 8226 can b...
Oncogene, 2008
In this study, we showed that the transforming growth factor b (TGFb)-mediated apoptosis of Burki... more In this study, we showed that the transforming growth factor b (TGFb)-mediated apoptosis of Burkitt's lymphoma BL41 cells is dependent on the BH3-only protein Bim. In contrast to what has been observed with other cell types, TGFb activation did not promote Bim upregulation in BL41 cells, but instead resulted in Bim release from the mitochondria. Indeed, Bim levels were high in healthy BL41 cells, in which they dimerized with the Bcl-2-like protein Mcl-1 at the mitochondrial surface. In healthy and TGFb-activated BL41 cells, unlike in epithelial cells or hepatocytes, Bim did not associate with Bcl-2 or Bcl-xL. TGFb activation of BL41 cells triggered the p38dependent activation of caspase-8, causing the cleavage of Mcl-1 and the transfer of Bim from the mitochondria to the cytoskeleton. In addition to mitochondrial activation, this relocation of Bim may facilitate the complete demise of a cell death that is beyond the commitment point to apoptosis and may represent a hallmark of the TGFbmediated apoptosis of human lymphoma B cells.
Kidney International, 2005
A novel biological assay to detect the active form of TGF-b in urine to monitor renal allograft r... more A novel biological assay to detect the active form of TGF-b in urine to monitor renal allograft rejection. Background. Transforming growth factor-b (TGF-b) plays an important role in renal fibrosis. Measurement of the concentration of the active form of TGF-b particularly in urine may help our understanding of the mechanism of chronic allograft nephropathy and could be used as a diagnostic tool. However, TGF-b release and activation are complex and, consequently, there is currently no accurate way to measure TGF-b activity. Methods. TGF-b-sensitive BL41 cells were stably transfected with a reporter plasmid harboring a synthetic TGF-b-inducible DNA sequence upstream from the luciferase gene. Cells were incubated with urine samples from normal donors or transplanted recipients with or without patent nephropathy, and the active form of TGF-b was determined as luciferase activity. Results. We have established a cell line which expresses luciferase activity in response to active TGF-b in a dosedependent manner. Moreover, the use of a histone deacetylase inhibitor greatly increased sensitivity to TGF-b and also stabilized luciferase inductibility. This test is highly specific to active TGF-b. Detectable levels of TGF-b were found in urine from patients with renal dysfunction due to acute or chronic renal allograft rejection (P < 0.001), but not in that from patients with stable, correctly functional kidneys. Conclusion. We describe a highly sensitive and specific assay for active TGF-b. We also show that, in cases of renal allograft, TGF-b expression is highly and significantly correlated with acute or chronic rejections. Numerous recent studies have investigated the role of transforming growth factor-b (TGF-b) in renal transplantation and strong evidence support the involvement of TGF-b in renal fibrosis [1]. TGF-b is a cytokine with profibrogenic but also anti-inflammatory and immunosuppressive effects [2]. In cases of renal allograft, on one
European Journal of Immunology, 1985
The C3d receptor is a specific marker of B lymphocytes. Recently we have shown that C3d receptor ... more The C3d receptor is a specific marker of B lymphocytes. Recently we have shown that C3d receptor activity is carried by a gp 140 membrane antigen. A polyclonal antibody has been prepared by immunizing a rabbit with highly purified gp 140 molecule isolated from membranes of the human B lymphoblastoid cell line Raji and its high specificity was previously demonstrated. We tested the effect of this antibody to the C3d receptor on the B cell proliferative response. Purified B cells from human blood were induced to proliferate by a B cell growth factor (BCGF)-containing partially purified supernatant from activated T cells. The anti-C3d receptor F(ab')2 enhanced the BCGF-dependent B cell proliferation. This effect was dose dependent, was observed in the presence of different concentrations of BCGF and did not correspond to a change in the time course of the response. The anti-C3d receptor F(ab')2 had no mitogenic effect in the absence of T cell supernatant. In contrast the undigested anti-C3d receptor IgG suppressed the BCGF-dependent B cell proliferation. These results emphasize the potentialities of anti-gp 140 F(ab')2 to explore the involvement of the C3d receptor in the regulation of B cell response to T cell products.
European Journal of Immunology, 1988
Atherosclerosis, 1999
We studied the cytotoxic effect of copper-oxidized LDL in human primary human umbilical vein endo... more We studied the cytotoxic effect of copper-oxidized LDL in human primary human umbilical vein endothelial cells (HUVEC) and the immortalized EA.hy 926 cell line. Copper oxidized LDL (50-200 mg apoB/ml) induced concentration-dependent apoptotic cell death in HUVEC but did not induce apoptosis in EA.hy 926 cells. Only necrotic EA.hy 926 cells were evidenced at all copper oxidized LDL concentrations (25-200 mg apoB/ml), oxidation states (lightly, moderately and extensively copper-oxidized LDL) and incubation periods (4, 8 and 20 h). The different mechanisms of cell death induced by copper-oxidized LDL in EA.hy 926 cells and HUVEC may be related to various factors such as cytokines. In this study, we investigated whether interleukin-8 may be implicated in this process. The interleukin-8 production was increased in EA.hy 926 cells but not in HUVEC incubated with oxidized LDL. This increase in EA.hy 926 cells was associated with necrosis but not apoptosis. Nevertheless, the addition of interleukin-8 to HUVEC did not inhibit apoptosis induced by oxidized LDL. As the lower antioxidant capacity of EA.hy 926 cells results in higher sensitivity to oxidized LDL cytotoxicity (as we previously described), the redox status of cells may also control the form of endothelial cell death. In atherosclerotic lesions, the formation of apoptotic endothelial cells may result in part from the induction by oxidized LDL.
The Journal of Immunology, 2000
Recent studies have defined several phenotypic and molecular changes associated with the maturati... more Recent studies have defined several phenotypic and molecular changes associated with the maturation of naive human B cells within the milieu of germinal centers. Although naive B cells serve as natural precursors to germinal center (GC)/memory (M) subpopulations, little is known about the physiological requirements for the survival of the naive B cell pool in the absence of cell-cell contact or Ag-mediated activation. Because IL-4 induces expression of several membrane receptors such as CD23 which are uniquely present on resting human naive B lymphocytes, we hypothesized that these cells might be intrinsically programmed to respond to IL-4 in the absence of cell division. Using buoyant density-dependent isolation and further enrichment by negative/positive selection of human naive and GC/M subpopulations, we characterized cytokine receptor moieties on these cells and analyzed their survival and growth in the presence of IL-4 or IL-10. Resting naive B cells expressed significantly hi...
Revue Francaise de Transfusion et Immuno-hématologie, 1985
ABSTRACT A specific IgM antibody response toward the trinitrophenol (TNP) hapten can be induced i... more ABSTRACT A specific IgM antibody response toward the trinitrophenol (TNP) hapten can be induced in mononuclear blood cell suspensions upon culture with a particulate antigen: polyacrylamide beads conjugated with the TNP hapten (TNP-PAA). The response, and its specificity, are demonstrated by an increase in the number of TNP binding B lymphocytes (specific rosette forming cells), by the appearance of cells producing anti-TNP antibody at a high rate (haemolytic plaques), (ELISA test). The anti-TNP response requires monocytes, the role of which is to produce interleukin-1 (IL-1) and T lymphocytes (belonging to the T4 helper subset) the role of which is to produce interleukins (the characterization of which is under study). We propose a model or B cell activation based on the following signals: an early specific signal, provided by the particulate antigen; several non specific signals, provided by T derived interleukins. The anti-TNP response is negatively regulated by monocytes, the functional states of which can be modified in certain situations (autoimmunity, aging) or influenced by glucocorticoids. Suppressor T lymphocytes of this response (not exclusively of the T8 phenotype) can be induced and this can allow the evaluation of T suppressor cell function. This was used in adult idiopathic thrombocytopenic purpura treated with high doses of intra-venous gammaglobulins.
Journal of Immunology, Jun 15, 1991
Differential regulation of surface Ig-and Lyb2-mediated B cell activation by cyclic AMP. I. Evide... more Differential regulation of surface Ig-and Lyb2-mediated B cell activation by cyclic AMP. I. Evidence for alternative regulation of signaling through two different receptors linked to phosphatidylinositol hydrolysis in murine B cells.
Cell Death & Differentiation, Jun 22, 2007
Heavy metals are important regulators of cell apoptosis. Manganese (Mn 2 þ) is a potent inducer o... more Heavy metals are important regulators of cell apoptosis. Manganese (Mn 2 þ) is a potent inducer of apoptosis in different cell types, but the precise mechanisms that mediate such effects are not well defined. We previously reported that Mn 2 þ was a potent apoptotic agent in human B cells, including lymphoma B cell lines. We show here that Mn 2 þ-induced cell death in human B cells is associated with caspase-8-dependent mitochondrial activation leading to caspase-3 activity and apoptosis. We used specific caspase-8 interfering shRNAs to reduce caspase-8 expression, and this also reduced Mn 2 þ-induced caspase-3 activation and apoptosis. Mn 2 þ-triggered caspase-8 activation is associated with a specific pathway, which is independent of Fas-associated death domain protein, and dependent on the sequential activation of p38-mitogen-activated protein kinase (p38 MAPK) and mitogen-and stress-response kinase 1 (MSK1). Inhibition of p38 activity using either pharmacological inhibitors or dominant-negative mutant forms of p38 blocked Mn 2 þ-mediated phosphorylation of MSK1 and blocked subsequent caspase-8 activation. However, specific inhibitors and the expression of a dominant-interfering mutant of MSK1 only inhibited caspase-8 activation, but not p38 activity. These findings suggest a novel model for the regulation of caspase-8 during Mn 2 þ-induced apoptosis based on the sequential activation of p38 MAPK, MSK1, caspase-8 and mitochondria, respectively.
Journal of Immunology, 1989
Biochemical and physicochemical characterization of mouse B cell growth factor: a lymphokine dist... more Biochemical and physicochemical characterization of mouse B cell growth factor: a lymphokine distinct from interleukin 2.
Journal of Immunology, Apr 1, 1997
IL-4 activates resting B cells and, in conjunction with cosignals such as anti-IgM (anti-mu) Ab o... more IL-4 activates resting B cells and, in conjunction with cosignals such as anti-IgM (anti-mu) Ab or CD40 ligand, modulates progression of B cells through the cell cycle, leading to proliferation. In this study, we show that the mitogenic combination of IL-4 and anti-mu Ab triggered induction of cyclin D3 and up-regulated cyclin-dependent kinase (cdk) 6 expression, whereas such regulation was not observed in B cells activated by IL-4 or anti-mu Ab alone. Furthermore, cyclin D3 immunoprecipitated fron as associated with cdk6, and the cyclin D3/cdk6 complex was able to phosphorylate recombinant retinoblastoma protein in vitro. In addition, B cells activated with either IL-4 or 1L-13 alone expressed a higher amount of p27kip1 (p27) cdk inhibitor than nonstimulated cells. In contrast, p27 expression was decreased when cells were activated with mitogenic combinations of IL-4 and anti-mu Ab or anti-CD40 mAb. We also observed that the IL-4-mediated inhibition of the proliferation of anti-mu/IL-2- or anti-mu/phorbol 12,13-dibutyrate-activated human leukemic B cells was associated with the maintenance of large amounts of p27 in these cells. These data suggest that IL-4 controls B cell proliferation by action during at least two steps of the regulation of the cell cycle, cyclin D3/cdk6 complex regulation and p27 inhibitor expression.
The Journal of Immunology
Engagement of the B cell Ag receptor can induce a suicide pathway in various B cell types. Earlie... more Engagement of the B cell Ag receptor can induce a suicide pathway in various B cell types. Earlier studies showed that anti-IgM mAb treatment triggers apoptotic death in the Burkitt lymphoma-derived cell line, Ramos. We show that two B cell surface molecules, CD19 and CD22, which have been reported to interact either functionally or structurally with the B cell Ag receptor, also stimulate cell suicide when sufficiently aggregated, both in the Ramos and EBV-infected Ramos AW cell lines. In conditions of lower cross-linking, both molecules enhance the apoptotic response induced by a suboptimal dose of anti-IgM mAb in Ramos cells, reinforcing the notion that CD19 and CD22 may be involved in the death pathway and modulate Ag-induced B cell apoptosis. Similar outcomes were obtained with human tonsillar B cells, which enter the death program upon treatment with cross-linked anti-IgM, -CD19, or -CD22 mAbs. These results indicate that Ag-induced B cell suicide may affect mature B cells in t...
The Journal of Immunology
The addition of monoclonal antibodies against the human C3b/C4b receptor (CR1) to cultures of per... more The addition of monoclonal antibodies against the human C3b/C4b receptor (CR1) to cultures of peripheral blood lymphocytes in the presence of suboptimal amounts of TNP bound to polyacrylamide beads enhanced by 150 to 400% the specific anti-TNP response, as measured by a plaque-forming cell assay on day 7. Anti-CR1 antibodies similarly enhanced the anti-fluorescein antibody response. Enhancement only occurred in cultures performed in the presence of the relevant antigen. No enhancing effect on the anti-TNP response was observed on addition to cultures of monoclonal antibodies directed against other surface antigens of B cells or an anti-T cell antibody of the same subclass as that of anti-CR1 antibodies. Anti-CR1 antibodies alone did not induce nonspecific B cell proliferation and did not provide B cells with a first signal for proliferation in the presence of a source of B cell growth factors. Anti-CR1 antibodies did not enhance the nonspecific proliferative response of B cells to g...
Blood, 1996
Human interleukin-13 (IL-13) acts at different stages of the normal B- cell maturation pathway wi... more Human interleukin-13 (IL-13) acts at different stages of the normal B- cell maturation pathway with a spectrum of biologic activities overlapping those of IL-4. B chronic lymphocytic leukemia (B-CLL) is characterized by the accumulation of slow-dividing and long-lived monoclonal B cells, arrested at the intermediate stage of their differentiation. In vitro, B-CLL cells exhibit a spontaneous apoptosis regulated by different cytokines. In this report, we show that IL-13 (10 to 200 ng/mL) acts directly on monoclonal B-CLL cells from 12 patients. (1) IL-13 enhances CD23 expression and induces soluble CD23 secretion by B-CLL cells but does not exhibit a growth factor activity. (2) IL-13 inhibits IL-2 responsiveness of B-CLL cells, activated either with IL-2 alone or through crosslinking of lgs or ligation of CD40 antigen. (3) IL-13 protects B-CLL cells from in vitro spontaneous apoptosis. The effects of IL-13 on neoplasic B cells were slightly less than those of IL-4 and occurred indepen...
Http Www Theses Fr, Oct 10, 2013
, that willingly participated in the evaluation of my work during my thesis. George Thyphronitis,... more , that willingly participated in the evaluation of my work during my thesis. George Thyphronitis, for encouraging me to move to France for an internship during my studies. Aimé Vazquez, for the warm welcome and his constant support since my first year in France. Nicolas Bidère, for an excellent cooperation and everyday presence and availability during my thesis.
Néphrologie & Thérapeutique, 2014
Introduction De nombreux arguments cliniques et experimentaux suggerent qu’un dysfonctionnement d... more Introduction De nombreux arguments cliniques et experimentaux suggerent qu’un dysfonctionnement du systeme immunitaire serait associe a la recidive de hyalinose segmentaire et focal (HSF). Nous avons identifie que CASK (calcium/calmodulin-dependent serine protein kinase) est presente dans le serum des patients et agit comme un facteur de permeabilite. Nous avons cherche si CASK pourrait etre exprimee dans les PBMC (cellules mononucleaires de sang peripherique) des patients. Patients et methodes Nous avons etudie l’expression de CASK dans les PBMC des patients (HSF, diabetique ayant syndrome nephrotique et sujet sain) par cytometrie en flux et dans plusieurs types de cellules hematopoietiques en immunoblot. Discussion et conclusion Nous avons observe que CASK est principalement exprimee par des cellules CD14+ (25 % ± 3 %) et dans une fraction plus faible des lymphocytes T (3 % ± 4 %) et des lymphocytes B (4 % ± 4,5 %) chez les patients atteints HSF. Elle n’est detectee ni chez les sujets sains ni chez les sujets ayant une nephropathie diabetique. L’expression de CASK est egalement detectee dans les lignees lymphocytaires KMH2 (cellule de Lymphome de Hodgkin) et Jurkat (leucemie des lymphocytes T). Dans les cultures primaires nous avons observe l’expression de CASK dans une sous-population de macrophage ayant une polarite du type M2 in vitro. Cette sous-population est caracterisee par un phenotype CD163 (Scavenger receptor) et CD206 (Mannose receptor C type 1) et joue un role dans la reparation tissulaire et l’angiogenese. Nos resultats suggerent qu’une expression/regulation aberrante de CASK pourrait etre generee dans un contexte inflammatoire par des monocytes/macrophages des patients atteints de HSF. La polarisation des macrophages in vitro nous permettra de comprendre le mecanisme de la regulation de la synthese de CASK.
The Journal of Immunology
We previously reported that p56lck expression is upregulated in human B lymphocytes upon mitogeni... more We previously reported that p56lck expression is upregulated in human B lymphocytes upon mitogenic stimulation. In this report, we characterized the molecules associated with p56lck in vivo in leukemic B cells costimulated with anti-mu Ab and IL-2 for 72 h. In vitro phosphorylation after p56lck immunoprecipitation indicated that p56lck is associated in vivo with the beta chain of the IL-2 receptor and p42 MAP kinase as well as a number of other proteins. Moreover, p56lck-associated MAP kinase is tyrosine and threonine phosphorylated, suggesting that it is activated. Prevention of DNA synthesis with aphidicolin abrogated this molecular association, and furthermore, cell cycle analysis with IL-2-dependent T cells showed that in cells in G1, MAP kinase was not associated to p56lck, whereas this p56lck-MAP kinase association was observed when cells are in S phase. Thus, p56lck and MAP kinase are only associated during S phase. These data suggest that MAP kinase in association with p56lc...
Transfection of MEFs with poly(I:C) triggers TBK1 accumulation at the centrosome at late time poi... more Transfection of MEFs with poly(I:C) triggers TBK1 accumulation at the centrosome at late time points. (A) MEFs were either left untreated (MOCK) or transfected with LMW poly(I:C) (5 μg/mL) for 4 h (trPoly(I:C)). TBK1 staining was then analyzed by immunofluorescence. The Golgi apparatus was labeled with an antibody against GM130, whereas TBK1 was detected with a rabbit monoclonal antibody. Scale bars, 10 μm. (B–E) MEFs were either left untreated (MOCK) or transfected with HMW poly(I:C) (5 μg/mL) for 4 h (trPoly(I:C)). The indicated proteins were analyzed by immunofluorescence staining with specific antibodies. The Golgi apparatus was labeled with an antibody against GM130, whereas centrosomes were labeled with an antibody against pericentrin. Scale bars, 10 μm. On the right, enlargement of the framed zone in the overlay. (PDF 1624 kb)
OPTN silencing impairs IRF3 signaling after RLR or TLR3 activation. (A) HEK293T cells were transf... more OPTN silencing impairs IRF3 signaling after RLR or TLR3 activation. (A) HEK293T cells were transfected with a control nonspecific siRNA (NS) or with five individual OPTNspecific siRNAs (OPTN A, B, C, D and E) or a NEMO-specific siRNA. The cells were then transfected, 48 h later, with an IFNβ promoter reporter or with a NF-κB reporter and the Renilla luciferase gene as an internal control. Then, 24 h after transfection, cells were either left unstimulated (Unstim) or infected with Sendai virus (+SeV) for 7 h. Luciferase assays were performed and the results were normalized against Renilla luciferase activity. The data shown are means ± SD from three independent experiments (analysis of variance and comparison with NS siRNA-transfected cells in Student's t-test). RLU, relative luminescence units. ns, not significant. (B) HEK293T cells were transfected with a control nonspecific siRNA (NS) or with two individual OPTN-specific siRNAs (OPTN A and OPTN B) or a NEMO-specific siRNA. The...
Cancer research, Jan 15, 1987
Using in vitro-growing myeloma cell lines, we studied the growth factors involved in human multip... more Using in vitro-growing myeloma cell lines, we studied the growth factors involved in human multiple myeloma, and particularly the potential of autocrine secretion and response to B-cell growth factor (BCGF) of RPMI 8226, the best-documented Epstein-Barr virus-negative human myeloma cell line. We found that three myeloma cell lines (RPMI 8226, U266, and IM9) produce an autostimulatory growth factor (AGF) and thus increase their own proliferation by 2- to 3-fold in cells cultured at low density. Optimal AGF production was obtained after 24 h of culture at a cell density ranging from 2.5 to 5 million cells/ml. The three myeloma cell lines produce type II BCGF, able to induce the proliferation of highly purified human peripheral blood B-cells, only after anti-mu activation. The BCGF produced by RPMI 8226 can be absorbed onto RPMI 8226 cells together with the RPMI 8226 AGF, and the two are copurified on gel filtration in a peak with an apparent molecular weight of 70,000. RPMI 8226 can b...
Oncogene, 2008
In this study, we showed that the transforming growth factor b (TGFb)-mediated apoptosis of Burki... more In this study, we showed that the transforming growth factor b (TGFb)-mediated apoptosis of Burkitt's lymphoma BL41 cells is dependent on the BH3-only protein Bim. In contrast to what has been observed with other cell types, TGFb activation did not promote Bim upregulation in BL41 cells, but instead resulted in Bim release from the mitochondria. Indeed, Bim levels were high in healthy BL41 cells, in which they dimerized with the Bcl-2-like protein Mcl-1 at the mitochondrial surface. In healthy and TGFb-activated BL41 cells, unlike in epithelial cells or hepatocytes, Bim did not associate with Bcl-2 or Bcl-xL. TGFb activation of BL41 cells triggered the p38dependent activation of caspase-8, causing the cleavage of Mcl-1 and the transfer of Bim from the mitochondria to the cytoskeleton. In addition to mitochondrial activation, this relocation of Bim may facilitate the complete demise of a cell death that is beyond the commitment point to apoptosis and may represent a hallmark of the TGFbmediated apoptosis of human lymphoma B cells.
Kidney International, 2005
A novel biological assay to detect the active form of TGF-b in urine to monitor renal allograft r... more A novel biological assay to detect the active form of TGF-b in urine to monitor renal allograft rejection. Background. Transforming growth factor-b (TGF-b) plays an important role in renal fibrosis. Measurement of the concentration of the active form of TGF-b particularly in urine may help our understanding of the mechanism of chronic allograft nephropathy and could be used as a diagnostic tool. However, TGF-b release and activation are complex and, consequently, there is currently no accurate way to measure TGF-b activity. Methods. TGF-b-sensitive BL41 cells were stably transfected with a reporter plasmid harboring a synthetic TGF-b-inducible DNA sequence upstream from the luciferase gene. Cells were incubated with urine samples from normal donors or transplanted recipients with or without patent nephropathy, and the active form of TGF-b was determined as luciferase activity. Results. We have established a cell line which expresses luciferase activity in response to active TGF-b in a dosedependent manner. Moreover, the use of a histone deacetylase inhibitor greatly increased sensitivity to TGF-b and also stabilized luciferase inductibility. This test is highly specific to active TGF-b. Detectable levels of TGF-b were found in urine from patients with renal dysfunction due to acute or chronic renal allograft rejection (P < 0.001), but not in that from patients with stable, correctly functional kidneys. Conclusion. We describe a highly sensitive and specific assay for active TGF-b. We also show that, in cases of renal allograft, TGF-b expression is highly and significantly correlated with acute or chronic rejections. Numerous recent studies have investigated the role of transforming growth factor-b (TGF-b) in renal transplantation and strong evidence support the involvement of TGF-b in renal fibrosis [1]. TGF-b is a cytokine with profibrogenic but also anti-inflammatory and immunosuppressive effects [2]. In cases of renal allograft, on one
European Journal of Immunology, 1985
The C3d receptor is a specific marker of B lymphocytes. Recently we have shown that C3d receptor ... more The C3d receptor is a specific marker of B lymphocytes. Recently we have shown that C3d receptor activity is carried by a gp 140 membrane antigen. A polyclonal antibody has been prepared by immunizing a rabbit with highly purified gp 140 molecule isolated from membranes of the human B lymphoblastoid cell line Raji and its high specificity was previously demonstrated. We tested the effect of this antibody to the C3d receptor on the B cell proliferative response. Purified B cells from human blood were induced to proliferate by a B cell growth factor (BCGF)-containing partially purified supernatant from activated T cells. The anti-C3d receptor F(ab')2 enhanced the BCGF-dependent B cell proliferation. This effect was dose dependent, was observed in the presence of different concentrations of BCGF and did not correspond to a change in the time course of the response. The anti-C3d receptor F(ab')2 had no mitogenic effect in the absence of T cell supernatant. In contrast the undigested anti-C3d receptor IgG suppressed the BCGF-dependent B cell proliferation. These results emphasize the potentialities of anti-gp 140 F(ab')2 to explore the involvement of the C3d receptor in the regulation of B cell response to T cell products.
European Journal of Immunology, 1988
Atherosclerosis, 1999
We studied the cytotoxic effect of copper-oxidized LDL in human primary human umbilical vein endo... more We studied the cytotoxic effect of copper-oxidized LDL in human primary human umbilical vein endothelial cells (HUVEC) and the immortalized EA.hy 926 cell line. Copper oxidized LDL (50-200 mg apoB/ml) induced concentration-dependent apoptotic cell death in HUVEC but did not induce apoptosis in EA.hy 926 cells. Only necrotic EA.hy 926 cells were evidenced at all copper oxidized LDL concentrations (25-200 mg apoB/ml), oxidation states (lightly, moderately and extensively copper-oxidized LDL) and incubation periods (4, 8 and 20 h). The different mechanisms of cell death induced by copper-oxidized LDL in EA.hy 926 cells and HUVEC may be related to various factors such as cytokines. In this study, we investigated whether interleukin-8 may be implicated in this process. The interleukin-8 production was increased in EA.hy 926 cells but not in HUVEC incubated with oxidized LDL. This increase in EA.hy 926 cells was associated with necrosis but not apoptosis. Nevertheless, the addition of interleukin-8 to HUVEC did not inhibit apoptosis induced by oxidized LDL. As the lower antioxidant capacity of EA.hy 926 cells results in higher sensitivity to oxidized LDL cytotoxicity (as we previously described), the redox status of cells may also control the form of endothelial cell death. In atherosclerotic lesions, the formation of apoptotic endothelial cells may result in part from the induction by oxidized LDL.
The Journal of Immunology, 2000
Recent studies have defined several phenotypic and molecular changes associated with the maturati... more Recent studies have defined several phenotypic and molecular changes associated with the maturation of naive human B cells within the milieu of germinal centers. Although naive B cells serve as natural precursors to germinal center (GC)/memory (M) subpopulations, little is known about the physiological requirements for the survival of the naive B cell pool in the absence of cell-cell contact or Ag-mediated activation. Because IL-4 induces expression of several membrane receptors such as CD23 which are uniquely present on resting human naive B lymphocytes, we hypothesized that these cells might be intrinsically programmed to respond to IL-4 in the absence of cell division. Using buoyant density-dependent isolation and further enrichment by negative/positive selection of human naive and GC/M subpopulations, we characterized cytokine receptor moieties on these cells and analyzed their survival and growth in the presence of IL-4 or IL-10. Resting naive B cells expressed significantly hi...
Revue Francaise de Transfusion et Immuno-hématologie, 1985
ABSTRACT A specific IgM antibody response toward the trinitrophenol (TNP) hapten can be induced i... more ABSTRACT A specific IgM antibody response toward the trinitrophenol (TNP) hapten can be induced in mononuclear blood cell suspensions upon culture with a particulate antigen: polyacrylamide beads conjugated with the TNP hapten (TNP-PAA). The response, and its specificity, are demonstrated by an increase in the number of TNP binding B lymphocytes (specific rosette forming cells), by the appearance of cells producing anti-TNP antibody at a high rate (haemolytic plaques), (ELISA test). The anti-TNP response requires monocytes, the role of which is to produce interleukin-1 (IL-1) and T lymphocytes (belonging to the T4 helper subset) the role of which is to produce interleukins (the characterization of which is under study). We propose a model or B cell activation based on the following signals: an early specific signal, provided by the particulate antigen; several non specific signals, provided by T derived interleukins. The anti-TNP response is negatively regulated by monocytes, the functional states of which can be modified in certain situations (autoimmunity, aging) or influenced by glucocorticoids. Suppressor T lymphocytes of this response (not exclusively of the T8 phenotype) can be induced and this can allow the evaluation of T suppressor cell function. This was used in adult idiopathic thrombocytopenic purpura treated with high doses of intra-venous gammaglobulins.