title: Targeting CD28, CTLA-4 and PD-L1 costimulation differentially controls immune synapses and function of human regulatory and conventional T-cells.
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.
authors.affiliation: Institut National de la Santé Et de la Recherche Médicale, Unité mixte de Recherche 1064, Nantes, France.
authors.forename: Nahzli
authors.initials: N
authors.lastname: Dilek
authors.affiliation: Institut National de la Santé Et de la Recherche Médicale, Unité mixte de Recherche 1064, Nantes, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Poirier
authors.affiliation: Institut National de la Santé Et de la Recherche Médicale, Unité mixte de Recherche 892, Nantes, France ; Cellular and Tissular Imaging Core Facility (MicroPICell), Nantes, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Hulin
authors.affiliation: Institut National de la Santé Et de la Recherche Médicale, Unité mixte de Recherche 1064, Nantes, France.
authors.forename: Flora
authors.initials: F
authors.lastname: Coulon
authors.affiliation: Institut National de la Santé Et de la Recherche Médicale, Unité mixte de Recherche 1064, Nantes, France ; Effimune S.A.S, Nantes, France.
authors.forename: Caroline
authors.initials: C
authors.lastname: Mary
authors.affiliation: Institut National de la Santé Et de la Recherche Médicale, Unité mixte de Recherche 1064, Nantes, France.
authors.forename: Simon
authors.initials: S
authors.lastname: Ville
authors.affiliation: Institut National de la Santé Et de la Recherche Médicale, Unité mixte de Recherche 892, Nantes, France.
authors.forename: Henri
authors.initials: H
authors.lastname: Vie
authors.affiliation: Institut National de la Santé Et de la Recherche Médicale, Unité mixte de Recherche 892, Nantes, France.
authors.forename: Béatrice
authors.initials: B
authors.lastname: Clémenceau
authors.affiliation: Institut National de la Santé Et de la Recherche Médicale, Unité mixte de Recherche 1064, Nantes, France ; Centre Hospitalier Universitaire de Nantes, Institut de Transplantation Urologie Néphrologie, Nantes, France ; Université de Nantes, Faculté de Médecine, Nantes, France.
authors.forename: Gilles
authors.initials: G
authors.lastname: Blancho
authors.affiliation: Institut National de la Santé Et de la Recherche Médicale, Unité mixte de Recherche 1064, Nantes, France ; Effimune S.A.S, Nantes, France ; Université de Nantes, Faculté de Médecine, Nantes, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Vanhove
mesh_terms: D000911:Antibodies, Monoclonal / Q000494:pharmacology; D018122:B7-1 Antigen / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology; D051940:B7-2 Antigen / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology; D060890:B7-H1 Antigen / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology*; D018106:CD28 Antigens / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology*; D060908:CTLA-4 Antigen / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology*; D002450:Cell Communication / Q000187:drug effects / Q000276:immunology; D002465:Cell Movement / Q000187:drug effects; D003713:Dendritic Cells / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D015870:Gene Expression; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects; D058990:Molecular Targeted Therapy; D011485:Protein Binding / Q000187:drug effects; D013602:T-Lymphocytes, Cytotoxic / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000166:cytology / Q000187:drug effects / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D018122:B7-1 Antigen; D051940:B7-2 Antigen; D060890:B7-H1 Antigen; C423236:CD274 protein, human; D018106:CD28 Antigens; D060908:CTLA-4 Antigen