Dialogue entre Cellules T et Cellules Dendritiques

Publications de l’équipe

Année de publication : 2017

Claire Hivroz, Paola Larghi, Mabel Jouve, Laurence Ardouin (2017 Mar 4)

Purification of LAT-Containing Membranes from Resting and Activated T Lymphocytes.

Methods in molecular biology (Clifton, N.J.) : 355-368 : DOI : 10.1007/978-1-4939-6881-7_21 En savoir plus
Résumé

In T lymphocytes, the immune synapse is an active zone of vesicular traffic. Directional transport of vesicular receptors and signaling molecules from or to the immune synapse has been shown to play an important role in T-cell receptor (TCR) signal transduction. However, how vesicular trafficking is regulating the activation of T cells is still a burning question, and the characterization of these intracellular compartments remains the first step to understand this process. We describe herein a protocol, which combines a separation of membranes on flotation gradient with an affinity purification of Strep-tagged fusion transmembrane proteins with Strep-Tactin(®) resin, allowing the purification of membranes containing the Strep-tagged molecule of interest. By keeping the membranes intact, this protocol leads to the purification of molecules physically associated with the Strep-tagged protein as well as of molecules present in the same membrane compartment: transmembrane proteins, proteins strongly associated with the membranes, and luminal proteins. The example shown herein is the purification of membrane compartment prepared from T lymphocytes expressing LAT fused to a Strep-tag.

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Année de publication : 2016

Asma Beldi-Ferchiou, Marion Lambert, Stéphanie Dogniaux, Frédéric Vély, Eric Vivier, Daniel Olive, Stéphanie Dupuy, Frank Levasseur, David Zucman, Céleste Lebbé, Damien Sène, Claire Hivroz, Sophie Caillat-Zucman (2016 Sep 24)

PD-1 mediates functional exhaustion of activated NK cells in patients with Kaposi sarcoma.

Oncotarget : DOI : 10.18632/oncotarget.12150 En savoir plus
Résumé

Programmed Death-1 (PD-1), an inhibitory receptor expressed by activated lymphocytes, is involved in regulating T- and B-cell responses. PD-1 and its ligands are exploited by a variety of cancers to facilitate tumor escape through PD-1-mediated functional exhaustion of effector T cells. Here, we report that PD-1 is upregulated on Natural Killer (NK) cells from patients with Kaposi sarcoma (KS). PD-1 was expressed in a sub-population of activated, mature CD56dimCD16pos NK cells with otherwise normal expression of NK surface receptors. PD-1pos NK cells from KS patients were hyporesponsive ex vivo following direct triggering of NKp30, NKp46 or CD16 activating receptors, or short stimulation with NK cell targets. PD-1pos NK cells failed to degranulate and release IFNγ, but exogenous IL-2 or IL-15 restored this defect. That PD-1 contributed to NK cell functional impairment and was not simply a marker of dysfunctional NK cells was confirmed in PD-1-transduced NKL cells. In vitro, PD-1 was induced at the surface of healthy control NK cells upon prolonged contact with cells expressing activating ligands, i.e. a condition mimicking persistent stimulation by tumor cells. Thus, PD-1 appears to plays a critical role in mediating NK cell exhaustion. The existence of this negative checkpoint fine-tuning NK activation highlights the possibility that manipulation of the PD-1 pathway may be a strategy for circumventing tumor escape not only from the T cell-, but also the NK-cell mediated immune surveillance.

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Lionel Guillou, Avin Babataheri, Michael Saitakis, Armelle Bohineust, Stéphanie Dogniaux, Claire Hivroz, Abdul I Barakat, Julien Husson (2016 Sep 9)

T lymphocyte passive deformation is controlled by unfolding of membrane surface reservoirs.

Molecular biology of the cell : DOI : mbc.E16-06-0414 En savoir plus
Résumé

T lymphocytes in the human body routinely undergo large deformations, both passively when going through narrow capillaries and actively when transmigrating across endothelial cells or squeezing through tissue. We investigate physical factors that enable and limit such deformations and explore how passive and active deformations may differ. Employing micropipette aspiration to mimic squeezing through narrow capillaries, we find that T lymphocytes maintain a constant volume while increasing their apparent membrane surface area upon aspiration. Human resting T lymphocytes, T lymphoblasts and the leukemic Jurkat T cells all exhibit membrane rupture above a critical membrane area expansion that is independent of either micropipette size or aspiration pressure. The unfolded membrane matches the excess membrane contained in microvilli and membrane folds, as determined using scanning electron microscopy. In contrast, during transendothelial migration, a form of active deformation, we find that the membrane surface exceeds by a factor of two the amount of membrane stored in microvilli and folds. These results suggest that internal membrane reservoirs need to be recruited, possibly through exocytosis, for large active deformations to occur.

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Chantal Lagresle-Peyrou, Sonia Luce, Farid Ouchani, Tayebeh Shabi Soheili, Hanem Sadek, Myriam Chouteau, Amandine Durand, Isabelle Pic, Jacek Majewski, Chantal Brouzes, Nathalie Lambert, Armelle Bohineust, Els Verhoeyen, François-Loïc Cosset, Aude Magerus-Chatinet, Frédéric Rieux-Laucat, Virginie Gandemer, Delphine Monnier, Catherine Heijmans, Marielle van Gijn, Virgil A Dalm, Nizar Mahlaoui, Jean-Louis Stephan, Capucine Picard, Anne Durandy, Sven Kracker, Claire Hivroz, Nada Jabado, Geneviève de Saint Basile, Alain Fischer, Marina Cavazzana, Isabelle André-Schmutz (2016 Jul 14)

X-linked primary immunodeficiency associated with hemizygous mutations in the moesin (MSN) gene.

The Journal of allergy and clinical immunology : DOI : S0091-6749(16)30423-7 En savoir plus
Résumé

We investigated 7 male patients (from 5 different families) presenting with profound lymphopenia, hypogammaglobulinemia, fluctuating monocytopenia and neutropenia, a poor immune response to vaccine antigens, and increased susceptibility to bacterial and varicella zoster virus infections.

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