Béatrice Clémenceau

Centre Hospitalier Universitaire de Nantes, Naoned, Pays de la Loire, France

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Publications (25)109.69 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Ovarian cancer has the highest mortality rate among gynecologic malignancies. The monoclonal antibody 12G4 specifically recognizes the human Müllerian inhibiting substance type II receptor (MISRII) that is strongly expressed in human granulosa cell tumors (GCT) and in the majority of human epithelial ovarian cancers (EOC). To determine whether MISRII represents an attractive target for antibody-based tumor therapy, we first confirmed by immunohistochemistry with 12G4 its expression in all tested GCT samples (4/4) and all, but one, EOC human tissue specimens (13/14). We then demonstrated in vitro the internalization of 12G4 in MISRII(high)COV434 cells after binding to MISRII and its ability to increase the apoptosis rate (FACS, DNA fragmentation) in MISRII(high)COV434 (GCT) and MISRII(medium)NIH-OVCAR-3 (EOC) cells that express different levels of MISRII. A standard (51)Cr release assay showed that 12G4 mediates antibody-dependent cell-meditated cytotoxicity. Finally, in vivo assessment of 12G4 anti-tumor effects showed a significant reduction of tumor growth and an increase of the median survival time in mice xenografted with MISRII(high)COV434 or MISRII(medium)NIH-OVCAR-3 cells and treated with 12G4 in comparison to controls treated with an irrelevant antibody. Altogether, our data indicate that MISRII is a new promising target for the control of ovarian GCTs and EOCs. A humanized version of the 12G4 antibody, named 3C23K, is in development for the targeted therapy of MISRII-positive gynecologic cancers.
    mAbs 09/2014; 6(5):1314-26. · 5.28 Impact Factor
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    ABSTRACT: Rituximab (RTX), a chimeric IgG1 monoclonal antibody directed against the CD20 antigen, has revolutionized the treatment of B-cell malignancies. Nevertheless, the relapsed/refractory rates are still high. One strategy to increase the clinical effectiveness of RTX is based on antibody-cytokine fusion protein (immunocytokine; ICK) vectorizing together at the tumor site the antibody effector activities and the cytokine co-signal required for the generation of cytotoxic cellular immunity. Such ICKs linking various antibody formats to interleukin (IL)-2 are currently being investigated in clinical trials and have shown promising results in cancer therapies. IL-15, a structurally-related cytokine, is now considered as having a better potential than IL-2 in antitumor immunotherapeutic strategies. We have previously engineered the fusion protein RLI, linking a soluble form of human IL-15Rα-sushi+ domain to human IL-15. Compared with IL-15, RLI displayed better biological activities in vitro and higher antitumor effects in vivo in murine and human cancer models. In this study, we investigated the advantages of fusing RLI to RTX. Anti-CD20-RLI kept its binding capacity to CD20, CD16 and IL-15 receptor and therefore fully retained both antibody effector functions (ADCC and CDC), and the cytokine potential of RLI. In a severe combined immunodeficiency (SCID) mouse model of disseminated residual lymphoma, anti-CD20-RLI was found to induce long-term survival of 90% of mice up to at least 120 days whereas RLI and RTX, alone or in combination, just delayed the disease onset (100% of death at 28, 40 and 51 days respectively). These findings suggest that such ICK could improve the clinical efficacy of RTX, particularly in patients with refractory B-cell lymphoma.
    mAbs 07/2014; 6(6):1026-37. · 5.28 Impact Factor
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    ABSTRACT: We report herein the results we obtained and the limitations we experienced during the production and use of a bank of Epstein-Barr virus (EBV)-transformed human cytotoxic T lymphocytes (EBV-CTLs). To assess the feasibility and toxicity of this strategy, we selected and stored, in liquid nitrogen, 4 billion EBV-CTLs from each of the 13 selected donors. Subsequently, in a multicenter phase I/II study, 11 patients with EBV-associated lymphoma resistant to conventional treatments received 1-3 doses of 5 million EBV-CTLs/kg with 1-3 and 0-4 compatibilities for human leukocyte antigen (HLA)-I and HLA-II, respectively. Except for one event of fever after injection, no immediate or delayed toxicity, no graft versus host disease, and no graft rejection attributable to CTL infusion were observed. Three patients presented complete remission and 1 partial remission after treatment. Considering the clinical options currently available, and the constrains associated with CTL preparation and implementation, we conclude that CTL banks should consist of a reasonably small number of cell lines with documented specificities. This objective could be more easily achieved if the few homozygous donors for the most frequent HLA alleles of the targeted population could be made available for such a project.
    Journal of immunotherapy (Hagerstown, Md.: 1997) 03/2014; · 3.20 Impact Factor
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    ABSTRACT: FcγRIIIA/CD16A, the low-affinity receptor for the IgG Fc portion expressed on human CD56(dim) NK cells and involved in Ab-dependent cell cytotoxicity, is shed upon NK cell activation. We found that recombinant a disintegrin and metalloprotease (ADAM) 17 cleaved the ectodomain of FcγRIIIA/CD16A and a peptide for which the sequence encompasses aa 191-201 of the FcγRIIIA/CD16A stalk region but not ADAM10. MALDI-TOF analysis revealed that the peptide was cleaved between Ala(195) and Val(196) (i.e., 1 aa upstream of the expected position). This location of the cleavage site was confirmed by the finding that ADAM17 failed to cleave a peptide in which Ala and Val were reversed. ADAM17 was found to be expressed on NK cells, and stimulation with PMA or N-ethyl-maleimide resulted in the shedding of FcγRIIIA/CD16A and CD62L, a specific substrate of ADAM17. Selective inhibition of ADAM17 prevented the shedding of both molecules. Moreover, the shedding of FcγRIIIA/CD16A was strongly correlated with degranulation when a wide range of CD56(dim) NK cell activating receptors were stimulated, whereas both ADAM17-dependent shedding and internalization were involved in FcγRIIIA/CD16A downmodulation when the latter was engaged. Finally, the shedding of FcγRIIIA/CD16A was restricted to activated cells, suggesting that ADAM17 acts mainly, if not exclusively, in cis. Taken together, our results demonstrated for the first time, to our knowledge, at the molecular level that ADAM17 cleaves the stalk region of FcγRIIIA/CD16A and identified its cleavage site. The shedding of FcγRIIIA/CD16A was at least partially ADAM17 dependent, and it may be considered as a marker of FcγRIIIA/CD16A-independent NK cell activation highly correlated with degranulation.
    The Journal of Immunology 12/2013; · 5.52 Impact Factor
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    ABSTRACT: To take advantage of the large number of well-characterized mouse immunoglobulins (IgGs) for the study of antibody-dependent cell-mediated cytotoxicity (ADCC) in human cells, we armed human cytotoxic lymphocytes with a mouse receptor for the Fc portion of IgG antibodies. The human ΝΚ-92 natural killer cell line was transduced with a mouse receptor gene (mCD16), which was stably expressed on the cell surface (referred to as NK-92 (mCD16) ). When tested against a B-lymphoblastoid cell line (BLCL) coated with mouse anti-CD20 IgG1, IgG2a or IgG2b monoclonal antibodies (mAbs), the newly expressed mouse Fc receptor enabled the NK-92 (mCD16) cells to kill the BLCL by ADCC. Next, using the NK-92 (mCD16) we compared mouse mAbs directed at B lineage specific CD antigens for their ability to induce ADCC against human Epstein-Barr virus- infected B lymphoblastoid (for anti-CD19, -CD20 and -CD21) or against myeloma (for anti-CD38 and -CD138) target cells. Our results demonstrated that the "NK-92 (mCD16) assay" allows convenient and sensitive discrimination of mouse mAbs for their ability to mediate ADCC in a human cellular system. In addition, our results provide examples of dissociation between opsonization and target cell killing through ADCC. These "murinized" human effector cells thus represent a convenient cellular tool for the study of ADCC.
    mAbs 05/2013; 5(4). · 5.28 Impact Factor
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    ABSTRACT: CD28, CTLA-4 and PD-L1, the three identified ligands for CD80/86, are pivotal positive and negative costimulatory molecules that, among other functions, control T cell motility and formation of immune synapse between T cells and antigen-presenting cells (APCs). What remains incompletely understood is how CD28 leads to the activation of effector T cells (Teff) but inhibition of suppression by regulatory T cells (Tregs), while CTLA-4 and PD-L1 inhibit Teff function but are crucial for the suppressive function of Tregs. Using alloreactive human T cells and blocking antibodies, we show here by live cell dynamic microscopy that CD28, CTLA-4, and PD-L1 differentially control velocity, motility and immune synapse formation in activated Teff versus Tregs. Selectively antagonizing CD28 costimulation increased Treg dwell time with APCs and induced calcium mobilization which translated in increased Treg suppressive activity, in contrast with the dampening effect on Teff responses. The increase in Treg suppressive activity after CD28 blockade was also confirmed with polyclonal Tregs. Whereas CTLA-4 played a critical role in Teff by reversing TCR-induced STOP signals, it failed to affect motility in Tregs but was essential for formation of the Treg immune synapse. Furthermore, we identified a novel role for PD-L1-CD80 interactions in suppressing motility specifically in Tregs. Thus, our findings reveal that the three identified ligands of CD80/86, CD28, CTLA-4 and PD-L1, differentially control immune synapse formation and function of the human Teff and Treg cells analyzed here. Individually targeting CD28, CTLA-4 and PD-L1 might therefore represent a valuable therapeutic strategy to treat immune disorders where effector and regulatory T cell functions need to be differentially targeted.
    PLoS ONE 01/2013; 8(12):e83139. · 3.53 Impact Factor
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    ABSTRACT: The cover shows a modified electron microscopic image of HPV16-virus-like particle (HPV16-VLP)-internalization by NK cells. The colour added to the cover image is purely for aesthetic purposes and has no biological significance. The original, unmodified image is from Renoux et al. (pp. 3240-3252) in which the authors demonstrate that HPV16-VLPs are taken up by NK cells by macropinocytosis. CD16 is shown to play a central role in the NK cell response to HPV16, being shown to be required for viral uptake, and for granzyme and cytokine release.
    European Journal of Immunology 11/2011; 41(11). · 4.97 Impact Factor
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    ABSTRACT: During serial assays designed to amplify natural killer (NK) cells in vitro, we observed that when peripheral blood mononuclear cells (PBMCs) from human immunodeficiency virus positive (HIV+) patients were stimulated for 2 weeks with an Epstein-Barr virus-infected B lymphoblastic cell line and interleukin-2, a well known procedure to amplify NK cells in vitro, 44.4 ± 18% CD3CD16 T lymphocytes were recovered together with NK cells, of which 78.2% expressed an αβ T-cell receptor (TCR). To identify the T-cell compartment from which they originated (naive, antigen experienced, CD16, or CD16), we first compared the results obtained with HIV+ patients' PBMCs (where essentially all CD8 cells are antigen experienced) with those obtained from cord blood lymphocytes (essentially naive) and PBMC from healthy donors (with variable antigen experience). Two weeks after stimulation, αβ TCR CD16 T lymphocytes increased from 0.3%, 2.2%, and 8.2% to 2.5%, 7.7%, and 36.3%, for cord blood, healthy donors, and HIV+ patients, respectively. Second, using cell-sorting experiments for CD16 cells and antibody-dependent cellular cytotoxicity assays, we demonstrated that a functional CD16 receptor could also be induced at the cell surface of αβ TCR CD16 T lymphocytes. Together, these results demonstrate that under stimulation conditions known to induce NK cell proliferation, a subset of αβ TCR CD16 T cells arises from antigen-experienced CD16 cells but also from antigen-experienced CD16 T lymphocytes, revealing the possibility to increase a patient's antibody-dependent cellular cytotoxicity potential through simple stimulation of this particular memory compartment.
    Journal of immunotherapy (Hagerstown, Md.: 1997) 09/2011; 34(7):542-9. · 3.20 Impact Factor
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    ABSTRACT: Human papillomavirus (HPV) infections account for more than 50% of infection-linked cancers in women worldwide. The immune system controls, at least partially, viral infection and around 90% of HPV-infected women clear the virus within two years. However, it remains unclear which immune cells are implicated in this process and no study has evaluated the direct interaction between HPVs and NK cells, a key player in host resistance to viruses and tumors. We demonstrated an NK-cell infiltration in HPV-associated preneoplastic cervical lesions. Since HPVs cannot grow in vitro, virus-like particles (VLPs) were used as a model for studying the NK-cell response against the virus. Interestingly, NK cells displayed higher cytotoxic activity and cytokine production (TNF-α and IFN-γ) in the presence of HPV-VLPs. Using flow cytometry and microscopy, we observed that NK-cell stimulation was linked to rapid VLP entry into these cells by macropinocytosis. Using CD16(+) and CD16(-) NK-cell lines and a CD16-blocking antibody, we demonstrated that CD16 is necessary for HPV-VLP internalization, as well as for degranulation and cytokine production. Thus, we show for the first time that NK cells interact with HPVs and can participate in the immune response against HPV-induced lesions.
    European Journal of Immunology 08/2011; 41(11):3240-52. · 4.97 Impact Factor
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    ABSTRACT: Monoclonal antibodies (mAb) against GD2 ganglioside have been shown to be effective for the treatment of neuroblastoma. Beneficial actions are, however, associated with generalized pain due to the binding of anti- GD2 mAbs to peripheral nerve fibers followed by complement activation. Neuroblastoma cells that express GD2 also express its O-acetyl derivative, O-acetyl- GD2 ganglioside (OAcGD2). Hence, we investigated the distribution of OAcGD2 in human tissues using mAb 8B6 to study the cross-reactivity of mAb 8B6 with human tissues. The distribution of OAcGD2 was performed in normal and malignant tissues using an immunoperoxydase technique. Anti-tumor properties of mAb 8B6 were studied in vitro and in vivo in a transplanted tumor model in mice. We found that OAcGD2 is not expressed by peripheral nerve fibers. Furthermore, we demonstrated that mAb 8B6 was very effective in the in vitro and in vivo suppression of the growth of tumor cells. Importantly, mAb 8B6 anti-tumor efficacy was comparable to that of mAb 14G2a specific to GD2. Development of therapeutic antibodies specific to OAcGD2 may offer treatment options with reduced adverse side effects, thereby allowing dose escalation of antibodies.
    PLoS ONE 01/2011; 6(9):e25220. · 3.53 Impact Factor
  • Cytokine 01/2011; 56(1):102-102. · 2.52 Impact Factor
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    ABSTRACT: Epstein-Barr virus (EBV)-transformed B-lymphoblastoid cell lines (LCLs) are used to prepare human EBV-specific T lymphocytes (EBV-CTL) in vitro. Within an LCL, up to 5-7% the cells release infectious EBV, and this has fostered safety concerns for therapeutic applications because of the exposure of T cells to EBV. The release of infectious viruses can be prevented by ganciclovir, but this drug may seriously affect LCL growth. In the wake of these concerns, the present work was designed to compile safety data on EBV-CTL preparation for the purpose of submission to a regulatory agency. We showed that further to supernatant exclusion, the number of EBV genome copies (EBVc) associated with the EBV-CTL always made up a constant proportion of the EBVc number detected in the culture supernatant. In addition, such was the case whether infectious virus could be produced by the LCL or not, suggesting that the EBV signal detected was due to a DNA contamination rather than an infection. Furthermore, we demonstrated that the number of EBVc associated with the EBV-CTL was highly sensitive to DNAse treatment, and finally that EBVc could no longer be detected after the EBV-CTL had been amplified in the absence of LCL. Consequently, during in vitro EBV-CTL preparation, either T cells cannot be infected or they die rapidly after EBV infection.
    Cancer Immunology and Immunotherapy 12/2010; 59(12):1867-75. · 3.64 Impact Factor
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    ABSTRACT: Intercellular transfer of cell surface proteins by trogocytosis is common and could affect T cell responses. Yet, the role of trogocytosis in T cell function is still elusive, and it is unknown whether a molecule, once captured by T cells, harbors the same biological properties as in donor APC. In this study, we showed that FcgammaR as well as the associated FcRgamma subunit could be detected at high levels on murine and human T cells after their intercellular transfer from FcgammaR-expressing APC. Capture of FcgammaR occurred during coculture of T cells with FcgammaR-expressing APC upon Ab- or Ag-mediated T cell stimulation. Once captured by T cells, FcgammaR were expressed in a conformation compatible with physiological function and conferred upon T cells the ability to bind immune complexes and to provision B cells with this source of Ag. However, we were unable to detect downstream signal or signaling-dependent function following the stimulation of FcgammaR captured by T cells, and biochemical studies suggested the improper integration of FcgammaR in the recipient T cell membrane. Thus, our study demonstrates that T cells capture FcgammaR that can efficiently exert ligand-binding activity, which, per se, could have functional consequences in T cell-B cell cooperation.
    The Journal of Immunology 11/2009; 183(10):6102-13. · 5.52 Impact Factor
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    European Journal of Immunology 02/2009; 39(1):324. · 4.97 Impact Factor
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    ABSTRACT: NK-cell function is regulated by a balance between inhibitory and activating killer cell immunoglobulin-like receptors (KIR) that specifically recognize HLA class I molecules. Using KIR-specific mAb to discriminate between KIR2DS1 and KIR2DL1 receptors, we show that KIR2DS1(+) NK cells are C2-alloreactive only from C2(-) individuals. Moreover, using an in vitro model of NK-cell expansion, we show here that the frequency of KIR2DL1(+) NK cells is significantly higher in the absence of C2 ligand on stimulator EBV-B cells than in its presence. This observation was made regardless of the presence or absence of the autologous C2 ligand, suggesting that the C2(-) EBV-B stimulator cells used in this in vitro model could activate unlicensed KIR2DL1(+) NK cells. In the case of KIR2DL1(+)/S1(+) genotyped individuals, KIR2DS1(+) NK-cell frequency was increased after stimulation with C2(+) compared with C2(-) stimulator B cells, but only from C2(-) individuals. Altogether, these data highlight the C2 alloreactivity of KIR2DS1(+) NK cells that is only observed in C2(-) individuals. These results provide new insights into the way in which NK KIR cell expansion might be regulated in an allogeneic environment.
    European Journal of Immunology 12/2008; 38(12):3474-86. · 4.97 Impact Factor
  • 23ème Congrès de la Société Française de Greffe de Moelle et de Thérapie Cellulaire; 10/2008
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    ABSTRACT: Human memory T cells are comprised of distinct populations with different homing potential and effector functions: central memory T cells that mount recall responses to Ags in secondary lymphoid organs, and effector memory T cells that confer immediate protection in peripheral tissues. In the present study we demonstrate that a proportion of effector memory T cells express FcgammaRIIIa (CD16), are perforin positive, and directly mediate Ab-dependent cytotoxicity ex vivo. This particular alphabeta T lymphocyte subset has the morphology of large granular lymphocytes, increases proportionately in vivo during reactive lymphocytosis, and can be detected in vitro among EBV-specific T lymphocytes after stimulation with EBV Ags. Consequently, during a normal immune response, amplification of these effector memory T lymphocytes that are capable of Ab-dependent cytotoxicity may have beneficial or harmful consequences depending on the presence of pathogen- or tissue-specific Abs, respectively.
    The Journal of Immunology 05/2008; 180(8):5327-34. · 5.52 Impact Factor
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    ABSTRACT: Human memory T cells are comprised of distinct populations with different homing potential and effector functions: central memory T cells that mount recall responses to Ags in secondary lymphoid organs, and effector memory T cells that confer immediate protection in peripheral tissues. In the present study we demonstrate that a proportion of effector memory T cells express FcγRIIIa (CD16), are perforin positive, and directly mediate Ab-dependent cytotoxicity ex vivo. This particular αβ T lymphocyte subset has the morphology of large granular lymphocytes, increases proportionately in vivo during reactive lymphocytosis, and can be detected in vitro among EBV-specific T lymphocytes after stimulation with EBV Ags. Consequently, during a normal immune response, amplification of these effector memory T lymphocytes that are capable of Ab-dependent cytotoxicity may have beneficial or harmful consequences depending on the presence of pathogen- or tissue-specific Abs, respectively.
    The Journal of Immunology 04/2008; 180(8):5327-5334. · 5.52 Impact Factor
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    ABSTRACT: We previously generated a mouse monoclonal antibody (mAb) specific for the tumor-associated GD2 ganglioside antigen. Here, we describe the development of a chimeric anti-GD2 mAb for more effective tumor immunotherapy. We cloned the cDNA encoding the immunoglobulin light and heavy chains of the 60C3 anti-GD2 mAb, and constructed chimeric genes by linking the cDNA fragments of the variable regions of the murine light and heavy chains to cDNA fragments of the human kappa and gamma1 constant regions, respectively. The resultant chimeric anti-GD2 mAb, c.60C3, showed identical binding affinity and specificity to that of its murine counterpart. Both c.60C3 and 60C3 were rapidly internalized by tumor cells at 37 degrees C. When human serum and human natural killer cells were used as effectors in complement-mediated cytotoxicity and antibody-dependent cell cytotoxicity, respectively, c.60C3 was more effective in killing GD2-expressing tumor cells. However, c.60C3 was ineffective at inducing cell death by apoptosis, although binding of 60C3 induced apoptotic death in vitro. In an in vivo, GD2-expressing, syngeneic tumor model, i.v. injection of c.60C3, but not of 60C3, significantly suppressed tumor growth in mice (P<0.0005). Immune effector functions mediated by this antibody and its potentially reduced immunogenicity make chimeric c.60C3 a promising therapeutic agent against neuroectodermic tumors.
    Clinical Cancer Research 09/2007; 13(18 Pt 2):5613s-5620s. · 7.84 Impact Factor
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    ABSTRACT: In the context of transplantation, donor and virus-specific T-lymphocyte infusions have demonstrated the dramatic potential of T cells as immune effectors. Unfortunately, most attempts to exploit the T-cell immune system against nonviral malignancies in the syngeneic setting have been disappointing. In contrast, treatments based on monoclonal antibodies (Abs) have been clinically successful and have demonstrated the clinical relevance of several antigens as therapeutic targets and the importance of the antibody-dependent cellular cytotoxicity (ADCC) pathway. In the present study, we considered the possibility of arming specific T cells with a receptor that would enable them to mediate ADCC. After transduction with a CD16/gamma receptor gene, CD4(+) and CD8(+) cytotoxic T lymphocytes displayed stable expression of the CD16 receptor at their surface. In the absence of Ab, CD16/gamma expression did not affect the capacity of specific T lymphocytes to kill their target following "natural" T-cell receptor recognition. When tested against the autologous B-lymphoblastoid cell line (BLCL) coated with anti-CD20 mAb, the newly expressed Fc receptor enabled the T cells to kill the BLCL through ADCC. Adoptive transfer of such newly designed immune effector may be considered to increase antibody efficiency by harnessing the immune potential of T cells.
    Blood 07/2006; 107(12):4669-77. · 9.78 Impact Factor

Publication Stats

101 Citations
109.69 Total Impact Points

Institutions

  • 2004–2013
    • Centre Hospitalier Universitaire de Nantes
      Naoned, Pays de la Loire, France
  • 2008–2011
    • French Institute of Health and Medical Research
      Lutetia Parisorum, Île-de-France, France
    • Unité Inserm U1077
      Caen, Lower Normandy, France
  • 2009
    • French National Centre for Scientific Research
      Lutetia Parisorum, Île-de-France, France