Réponses immunitaires et cancer

Publications de l’équipe

Année de publication : 2012

Elodie Segura, Maxime Touzot, Armelle Bohineust, Antonio Cappuccio, Gilles Chiocchia, Anne Hosmalin, Marc Dalod, Vassili Soumelis, Sebastian Amigorena (2012 May 11)

Human inflammatory dendritic cells induce Th17 cell differentiation.

Immunity : 336-48 : DOI : 10.1016/j.immuni.2012.10.018 En savoir plus
Résumé

Dendritic cells (DCs) are critical regulators of immune responses. Under noninflammatory conditions, several human DC subsets have been identified. Little is known, however, about the human DC compartment under inflammatory conditions. Here, we characterize a DC population found in human inflammatory fluids that displayed a phenotype distinct from macrophages from the same fluids and from steady-state lymphoid organ and blood DCs. Transcriptome analysis showed that they correspond to a distinct DC subset and share gene signatures with in vitro monocyte-derived DCs. Moreover, human inflammatory DCs, but not inflammatory macrophages, stimulated autologous memory CD4(+) T cells to produce interleukin-17 and induce T helper 17 (Th17) cell differentiation from naive CD4(+) T cells through the selective secretion of Th17 cell-polarizing cytokines. We conclude that inflammatory DCs represent a distinct human DC subset and propose that they are derived from monocytes and are involved in the induction and maintenance of Th17 cell responses.

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Elodie Segura, Jenny Valladeau-Guilemond, Marie-Hélène Donnadieu, Xavier Sastre-Garau, Vassili Soumelis, Sebastian Amigorena (2012 Mar 21)

Characterization of resident and migratory dendritic cells in human lymph nodes.

The Journal of experimental medicine : 653-60 : DOI : 10.1084/jem.20111457 En savoir plus
Résumé

Dendritic cells (DCs) initiate adaptive immune responses in lymph nodes (LNs). In mice, LN DCs can be divided into resident and tissue-derived populations, the latter of which migrate from the peripheral tissues. In humans, different subsets of DCs have been identified in the blood, spleen, and skin, but less is known about populations of resident and migratory tissue-derived DCs in LNs. We have analyzed DCs in human LNs and identified two populations of resident DCs that are present in all LNs analyzed, as well as in the spleen and tonsil, and correspond to the two known blood DC subtypes. We also identify three main populations of skin-derived migratory DCs that are present only in skin-draining LNs and correspond to the DC subsets found in the skin. Resident DCs subsets induce both Th1 and Th2 cytokines in naive allogeneic T lymphocytes, whereas the corresponding blood subsets failed to induce efficient Th2 polarization. LN-resident DCs also cross-present antigen without in vitro activation, whereas blood DCs fail to do so. Among migratory DCs, one subset was poor at both CD4(+) and CD8(+) T cell activation, whereas the other subsets induced only Th2 polarization. We conclude that in humans, skin-draining LNs host both resident and migratory DC subsets with distinct functional abilities.

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Rhys S Allan, Elina Zueva, Florence Cammas, Heidi A Schreiber, Vanessa Masson, Gabrielle T Belz, Danièle Roche, Christèle Maison, Jean-Pierre Quivy, Geneviève Almouzni, Sebastian Amigorena (2012 Mar 8)

An epigenetic silencing pathway controlling T helper 2 cell lineage commitment.

Nature : 249-53 : DOI : 10.1038/nature11173 En savoir plus
Résumé

During immune responses, naive CD4+ T cells differentiate into several T helper (TH) cell subsets under the control of lineage-specifying genes. These subsets (TH1, TH2 and TH17 cells and regulatory T cells) secrete distinct cytokines and are involved in protection against different types of infection. Epigenetic mechanisms are involved in the regulation of these developmental programs, and correlations have been drawn between the levels of particular epigenetic marks and the activity or silencing of specifying genes during differentiation. Nevertheless, the functional relevance of the epigenetic pathways involved in TH cell subset differentiation and commitment is still unclear. Here we explore the role of the SUV39H1–H3K9me3–HP1α silencing pathway in the control of TH2 lineage stability. This pathway involves the histone methylase SUV39H1, which participates in the trimethylation of histone H3 on lysine 9 (H3K9me3), a modification that provides binding sites for heterochromatin protein 1α (HP1α) and promotes transcriptional silencing. This pathway was initially associated with heterochromatin formation and maintenance but can also contribute to the regulation of euchromatic genes. We now propose that the SUV39H1–H3K9me3–HP1α pathway participates in maintaining the silencing of TH1 loci, ensuring TH2 lineage stability. In TH2 cells that are deficient in SUV39H1, the ratio between trimethylated and acetylated H3K9 is impaired, and the binding of HP1α at the promoters of silenced TH1 genes is reduced. Despite showing normal differentiation, both SUV39H1-deficient TH2 cells and HP1α-deficient TH2 cells, in contrast to wild-type cells, expressed TH1 genes when recultured under conditions that drive differentiation into TH1 cells. In a mouse model of TH2-driven allergic asthma, the chemical inhibition or loss of SUV39H1 skewed T-cell responses towards TH1 responses and decreased the lung pathology. These results establish a link between the SUV39H1–H3K9me3–HP1α pathway and the stability of TH2 cells, and they identify potential targets for therapeutic intervention in TH2-cell-mediated inflammatory diseases.

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Année de publication : 2011

Laurence Zitvogel, Sebastian Amigorena, Jean-Luc Teillaud (2011 Dec 2)

[About Ralph M. Steinman and dendritic cells].

Médecine sciences : M/S : 1028-34 : DOI : 10.1051/medsci/20112711022 En savoir plus
Résumé

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Juan Sabatte, Wolfgang Faigle, Ana Ceballos, Willy Morelle, Christian Rodríguez Rodrígues, Federico Remes Lenicov, Michel Thépaut, Franck Fieschi, Emilio Malchiodi, Marisa Fernández, Fernando Arenzana-Seisdedos, Hugues Lortat-Jacob, Jean-Claude Michalski, Jorge Geffner, Sebastian Amigorena (2011 Oct 21)

Semen clusterin is a novel DC-SIGN ligand.

Journal of immunology (Baltimore, Md. : 1950) : 5299-309 : DOI : 10.4049/jimmunol.1101889 En savoir plus
Résumé

The C-type lectin receptor dendritic cell-specific ICAM-3-grabbing nonintegrin (DC-SIGN) is an important player in the recognition of pathogens by dendritic cells. A plethora of pathogens including viruses, bacteria, parasites, and fungi are recognized by DC-SIGN through both mannose and fucose-containing glycans expressed on the pathogen surface. In this study, we identified semen clusterin as a novel DC-SIGN ligand. Semen clusterin, but not serum clusterin, expresses an extreme abundance of fucose-containing blood-type Ags such as Le(x) and Le(y), which are both excellent DC-SIGN ligands. These motifs enable semen clusterin to bind DC-SIGN with very high affinity (K(d) 76 nM) and abrogate the binding of HIV-1 to DC-SIGN. Depletion of clusterin from semen samples, however, did not completely prevent the ability of semen to inhibit the capture of HIV-1 by DC-SIGN, supporting that besides clusterin, semen contains other DC-SIGN ligands. Further studies are needed to characterize these ligands and define their contribution to the DC-SIGN-blocking activity mediated by semen. Clusterin is an enigmatic protein involved in a variety of physiologic and pathologic processes including inflammation, atherosclerosis, and cancer. Our results uncover an unexpected heterogeneity in the glycosylation pattern of clusterin and suggest that the expression of high concentrations of fucose-containing glycans enables semen clusterin to display a unique set of biological functions that might affect the early course of sexually transmitted infectious diseases.

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Juan Sabatté, Federico Remes Lenicov, Mercedes Cabrini, Christian Rodriguez Rodrigues, Matías Ostrowski, Ana Ceballos, Sebastián Amigorena, Jorge Geffner (2011 Jul 20)

The role of semen in sexual transmission of HIV: beyond a carrier for virus particles.

Microbes and infection / Institut Pasteur : 977-82 : DOI : 10.1016/j.micinf.2011.06.005 En savoir plus
Résumé

Unprotected sexual intercourse between discordant couples is by far the most frequent mode of HIV-1 (human immunodeficiency virus type 1) transmission being semen the main vector for HIV-1 dissemination worldwide. Semen is usually considered merely as a vehicle for HIV-1 transmission. In this review we discuss recent observations suggesting that beyond being a carrier for virus particles semen markedly influences the early events involved in sexual transmission of HIV through the mucosal barriers.

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Ingrid S Zeelenberg, Wendy W C van Maren, Alexandre Boissonnas, Maaike A Van Hout-Kuijer, Martijn H M G M Den Brok, Jori A L Wagenaars, Alie van der Schaaf, Eric J R Jansen, Sebastian Amigorena, Clotilde Théry, Carl G Figdor, Gosse J Adema (2011 Jun 28)

Antigen localization controls T cell-mediated tumor immunity.

Journal of immunology (Baltimore, Md. : 1950) : 1281-8 : DOI : 10.4049/jimmunol.1003905 En savoir plus
Résumé

Effective antitumor immunotherapy requires the identification of suitable target Ags. Interestingly, many of the tumor Ags used in clinical trials are present in preparations of secreted tumor vesicles (exosomes). In this study, we compared T cell responses elicited by murine MCA101 fibrosarcoma tumors expressing a model Ag at different localizations within the tumor cell in association with secreted vesicles (exosomes), as a nonsecreted cell-associated protein, or as secreted soluble protein. Remarkably, we demonstrated that only the tumor-secreting vesicle-bound Ag elicited a strong Ag-specific CD8(+) T cell response, CD4(+) T cell help, Ag-specific Abs, and a decrease in the percentage of immunosuppressive regulatory T cells in the tumor. Moreover, in a therapeutic tumor model of cryoablation, only in tumors secreting vesicle-bound Ag could Ag-specific CD8(+) T cells still be detected up to 16 d after therapy. We concluded that the localization of an Ag within the tumor codetermines whether a robust immunostimulatory response is elicited. In vivo, vesicle-bound Ag clearly skews toward a more immunogenic phenotype, whereas soluble or cell-associated Ag expression cannot prevent or even delay outgrowth and results in tumor tolerance. This may explain why particular immunotherapies based on these vesicle-bound tumor Ags are potentially successful. Therefore, we conclude that this study may have significant implications in the discovery of new tumor Ags suitable for immunotherapy and that their location should be taken into account to ensure a strong antitumor immune response.

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Pascale Hubert, Adèle Heitzmann, Sophie Viel, André Nicolas, Xavier Sastre-Garau, Pablo Oppezzo, Otto Pritsch, Eduardo Osinaga, Sebastian Amigorena (2011 Jun 24)

Antibody-dependent cell cytotoxicity synapses form in mice during tumor-specific antibody immunotherapy.

Cancer research : 5134-43 : DOI : 10.1158/0008-5472.CAN-10-4222 En savoir plus
Résumé

Antibody-dependent cell cytotoxicity (ADCC) plays a critical role in monoclonal antibody (mAb)-mediated cancer therapy. ADCC, however, has not been directly shown in vivo but inferred from the requirement for IgG Fc receptors (FcγR) in tumor rejection in mice. Here, we investigated the mechanism of action of a Tn antigen-specific chimeric mAb (Chi-Tn), which binds selectively to a wide variety of carcinomas, but not to normal tissues, in both humans and mice. Chi-Tn mAb showed no direct toxicity against carcinomas cell lines in vitro but induced the rejection of a murine breast tumor in 80% to 100% of immunocompetent mice, when associated with cyclophosphamide. Tumor rejection was abolished in Fc receptors-associated γ chain (FcR-γ)-deficient mice, suggesting a role for ADCC. Indeed, tumor cells formed stable conjugates in vivo with FcR-γ chain-expressing macrophages and neutrophils in Chi-Tn mAb-treated but not in control mAb-treated mice. The contact zone between tumor cells and ADCC effectors accumulated actin, FcγR and phospho-tyrosines. The in vivo formed ADCC synapses were organized in multifocal supra-molecular activation clusters. These results show that in vivo ADCC mediated by macrophages and neutrophils during tumor rejection by Chi-Tn mAb involves a novel type of multifocal immune synapse between effectors of innate immunity and tumor cells.

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Ignacio Cebrian, Geraldine Visentin, Nicolas Blanchard, Mabel Jouve, Alexandre Bobard, Catarina Moita, Jost Enninga, Luis F Moita, Sebastian Amigorena, Ariel Savina (2011 May 17)

Sec22b regulates phagosomal maturation and antigen crosspresentation by dendritic cells.

Cell : 1355-68 : DOI : 10.1016/j.cell.2011.11.021 En savoir plus
Résumé

Antigen (Ag) crosspresentation by dendritic cells (DCs) involves the presentation of internalized Ags on MHC class I molecules to initiate CD8+ T cell-mediated immunity in response to certain pathogens and tumor cells. Here, we identify the SNARE Sec22b as a specific regulator of Ag crosspresentation. Sec22b localizes to the ER-Golgi intermediate compartment (ERGIC) and pairs to the plasma membrane SNARE syntaxin 4, which is present in phagosomes (Phgs). Depletion of Sec22b inhibits the recruitment of ER-resident proteins to Phgs and to the vacuole containing the Toxoplasma gondii parasite. In Sec22b-deficient DCs, crosspresentation is compromised after Ag phagocytosis or endocytosis and after invasion by T. gondii. Sec22b silencing inhibited Ag export to the cytosol and increased phagosomal degradation by accelerating lysosomal recruitment. Our findings provide insight into an intracellular traffic pathway required for crosspresentation and show that Sec22b-dependent recruitment of ER proteins to Phgs critically influences phagosomal functions in DCs.

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Année de publication : 2010

G Sugano, I Bernard-Pierrot, M Laé, C Battail, Y Allory, N Stransky, S Krumeich, M-L Lepage, P Maille, M-H Donnadieu, C C Abbou, S Benhamou, T Lebret, X Sastre-Garau, S Amigorena, F Radvanyi, C Théry (2010 Oct 20)

Milk fat globule–epidermal growth factor–factor VIII (MFGE8)/lactadherin promotes bladder tumor development.

Oncogene : 642-53 : DOI : 10.1038/onc.2010.446 En savoir plus
Résumé

Milk fat globule-epidermal growth factor-factor VIII (MFGE8), also called lactadherin or SED1, is a secreted integrin-binding protein that promotes elimination of apoptotic cells by phagocytes leading to tolerogenic immune responses, and vascular endothelial growth factor (VEGF)-induced angiogenesis: two important processes for cancer development. Here, by transcriptomic analysis of 228 biopsies of bladder carcinomas, we observed overexpression of MFGE8 during tumor development, correlated with expression of genes involved in cell adhesion or migration and in immune responses, but not in VEGF-mediated angiogenesis. To test whether MFGE8 expression was instrumental in bladder tumor development, or a simple consequence of this development, we used genetic ablation in a mouse model of carcinogen-induced bladder carcinoma. We showed that Mfge8 was also upregulated in mouse carcinoma, and that in its absence, Mfge8-deficient animals developed less advanced tumors. Angiogenesis was similar in carcinogen-treated Mfge8-expressing or -deficient bladders, thus ruling out a major role of the proangiogenic function of Mfge8 for its protumoral role. By contrast, the tumor-promoting role of Mfge8 was not observed anymore in mice devoid of adaptive immune system, and human tumors overexpressing MFGE8 where invaded with macrophages and regulatory T cells, thus suggesting that MFGE8/lactadherin favors development of bladder tumors at least partly by an immune system-dependent mechanism. Our observations suggest future use of MFGE8-inhibiting molecules as therapies of bladder carcinomas, and of a limited number of other human cancers, in which our analysis of public databases also revealed overexpression of MFGE8.

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Vanessa Contreras, Céline Urien, Rachel Guiton, Yannick Alexandre, Thien-Phong Vu Manh, Thibault Andrieu, Karine Crozat, Luc Jouneau, Nicolas Bertho, Mathieu Epardaud, Jayne Hope, Ariel Savina, Sebastian Amigorena, Michel Bonneau, Marc Dalod, Isabelle Schwartz-Cornil (2010 Aug 13)

Existence of CD8α-like dendritic cells with a conserved functional specialization and a common molecular signature in distant mammalian species.

Journal of immunology (Baltimore, Md. : 1950) : 3313-25 : DOI : 10.4049/jimmunol.1000824 En savoir plus
Résumé

The mouse lymphoid organ-resident CD8alpha(+) dendritic cell (DC) subset is specialized in Ag presentation to CD8(+) T cells. Recent evidence shows that mouse nonlymphoid tissue CD103(+) DCs and human blood DC Ag 3(+) DCs share similarities with CD8alpha(+) DCs. We address here whether the organization of DC subsets is conserved across mammals in terms of gene expression signatures, phenotypic characteristics, and functional specialization, independently of the tissue of origin. We study the DC subsets that migrate from the skin in the ovine species that, like all domestic animals, belongs to the Laurasiatheria, a distinct phylogenetic clade from the supraprimates (human/mouse). We demonstrate that the minor sheep CD26(+) skin lymph DC subset shares significant transcriptomic similarities with mouse CD8alpha(+) and human blood DC Ag 3(+) DCs. This allowed the identification of a common set of phenotypic characteristics for CD8alpha-like DCs in the three mammalian species (i.e., SIRP(lo), CADM1(hi), CLEC9A(hi), CD205(hi), XCR1(hi)). Compared to CD26(-) DCs, the sheep CD26(+) DCs show 1) potent stimulation of allogeneic naive CD8(+) T cells with high selective induction of the Ifngamma and Il22 genes; 2) dominant efficacy in activating specific CD8(+) T cells against exogenous soluble Ag; and 3) selective expression of functional pathways associated with high capacity for Ag cross-presentation. Our results unravel a unifying definition of the CD8alpha(+)-like DCs across mammalian species and identify molecular candidates that could be used for the design of vaccines applying to mammals in general.

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Sebastian Amigorena, Ariel Savina (2010 Feb 23)

Intracellular mechanisms of antigen cross presentation in dendritic cells.

Current opinion in immunology : 109-17 : DOI : 10.1016/j.coi.2010.01.022 En savoir plus
Résumé

The induction of most CD8+ T cell responses by dendritic cells (DCs) requires the presentation of peptides from internalized antigen by class I MHC molecules. Increasing number of reports have shown that cross presentation is involved in transplant rejection, in immune responses to viral infections, in certain autoimmune diseases and cancer. The precise role of cross presentation in the initiation of immune responses in vivo, however, remains a matter of debate. This ongoing controversy is, at least in part, due to a lack of understanding of the molecular machinery that determine cross presentation pathways in terms of cell biology. The present review aims to summarize recent insights and advances that help enlighten the intracellular steps of antigen cross presentation in DCs.

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Alexandre Boissonnas, Alix Scholer-Dahirel, Virginie Simon-Blancal, Luigia Pace, Fabien Valet, Adrien Kissenpfennig, Tim Sparwasser, Bernard Malissen, Luc Fetler, Sebastian Amigorena (2010 Feb 9)

Foxp3+ T cells induce perforin-dependent dendritic cell death in tumor-draining lymph nodes.

Immunity : 266-78 : DOI : 10.1016/j.immuni.2009.11.015 En savoir plus
Résumé

Regulatory T (Treg) cells limit the onset of effective antitumor immunity, through yet-ill-defined mechanisms. We showed the rejection of established ovalbumin (OVA)-expressing MCA101 tumors required both the adoptive transfer of OVA-specific CD8(+) T cell receptor transgenic T cells (OTI) and the neutralization of Foxp3(+) T cells. In tumor-draining lymph nodes, Foxp3(+) T cell neutralization induced a marked arrest in the migration of OTI T cells, increased numbers of dendritic cells (DCs), and enhanced OTI T cell priming. Using an in vitro cytotoxic assay and two-photon live microscopy after adoptive transfer of DCs, we demonstrated that Foxp3(+) T cells induced the death of DCs in tumor-draining lymph nodes, but not in the absence of tumor. DC death correlated with Foxp3(+) T cell-DC contacts, and it was tumor-antigen and perforin dependent. We conclude that Foxp3(+) T cell-dependent DC death in tumor-draining lymph nodes limits the onset of CD8(+) T cell responses.

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Année de publication : 2009

Ariel Savina, Pablo Vargas, Pierre Guermonprez, Ana-Maria Lennon, Sebastian Amigorena (2009 Nov 27)

Measuring pH, ROS production, maturation, and degradation in dendritic cell phagosomes using cytofluorometry-based assays.

Methods in molecular biology (Clifton, N.J.) : 383-402 : DOI : 10.1007/978-1-60761-421-0_25 En savoir plus
Résumé

Phagosomes are complex organelles that form after ingestion by phagocytic cells of pathogens, dying cells, or cell debris. Highly dynamic interactions of phagosomes first with endosomes and then with lysosomes lead to the maturation of phagosomes into phagolysosomes. Contrary to other phagocytes, which degrade ingested particles to amino acids, dendritic cells only partially degrade ingested proteins, preserving short peptides for the onset of adaptive immune responses. We have modified a series of latex bead-based techniques, previously reported, in order to analyze phagosome maturation using flow cytometry. The analysis of the phagosomal pH, degradation, or oxidation relies on techniques based on the fate of specific probes bound to particles to be phagocytosed. These techniques are very sensitive and quantitative.

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Fernando E Sepulveda, Sophia Maschalidi, Renaud Colisson, Lea Heslop, Cristina Ghirelli, Emna Sakka, Ana-Maria Lennon-Duménil, Sebastian Amigorena, Lucien Cabanie, Bénédicte Manoury (2009 Nov 3)

Critical role for asparagine endopeptidase in endocytic Toll-like receptor signaling in dendritic cells.

Immunity : 737-48 : DOI : 10.1016/j.immuni.2009.09.013 En savoir plus
Résumé

Intracellular Toll-like receptor 3 (TLR3), TLR7, and TLR9 localize in endosomes and recognize single-stranded RNA and nucleotides from viruses and bacteria. This interaction induces their conformational changes resulting in the production of proinflammatory cytokines and upregulation of cell surface molecules. TLR9 requires a proteolytic cleavage for its signaling. Here, we report that myeloid and plasmacytoid dendritic cells (DCs) deficient for the asparagine endopeptidase (AEP), a cysteine lysosomal protease, showed a decrease in the secretion of proinflammatory cytokines in response to TLR9 stimulation in vitro and in vivo. Upon stimulation, full-length TLR9 was cleaved into a 72 kDa fragment and this processing was strongly reduced in DCs lacking AEP. Processed TLR9 coeluted with the adaptor molecule MyD88 and AEP after size exclusion chromatography. When expressed in AEP-deficient DCs, the 72 kDa proteolytic fragment restored TLR9 signaling. Thus, our results identify an endocytic protease playing a critical role in TLR processing and signaling in DCs.

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