[Show abstract][Hide abstract] ABSTRACT: Chemokine receptors have been implicated in a wide range of CNS inflammatory diseases and have important roles in the recruitment and positioning of immune cells within tissues. Among them, the chemokine (C-C motif) receptor 5 (CCR5) can be targeted by maraviroc, a readily available and well-tolerated drug that was developed for the treatment of HIV. Correlative evidence implicates the CCR5-chemokine axis in multiple sclerosis, Rasmussen encephalitis, progressive multifocal leukoencephalopathy-associated immune reconstitution inflammatory syndrome, and infectious diseases, such as cerebral malaria and HIV-associated neurocognitive disorders. On the basis of this evidence, we postulate in this Review that CCR5 antagonists, such as maraviroc, offer neuroprotective benefits in settings in which CCR5 promotes deleterious neuroinflammation, particularly in diseases in which CD8(+) T cells seem to play a pivotal role.
Full-text · Article · Jan 2016 · Nature Reviews Neurology
[Show abstract][Hide abstract] ABSTRACT: Objective:
Narcolepsy with cataplexy is tightly associated with the HLA class II allele DQB1*06:02. Evidence indicates a complex contribution of HLA class II genes to narcolepsy susceptibility with a recent independent association with HLA-DPB1. The cause of narcolepsy is supposed be an autoimmune attack against hypocretin-producing neurons. Despite the strong association with HLA class II, there is no evidence for CD4+ T-cell-mediated mechanism in narcolepsy. Since neurons express class I and not class II molecules, the final effector immune cells involved might include class I-restricted CD8+ T-cells.
HLA class I (A, B, and C) and II (DQB1) genotypes were analyzed in 944 European narcolepsy with cataplexy patients and in 4043 control subjects matched by country of origin. All patients and controls were DQB1*06:02 positive and class I associations were conditioned on DQB1 alleles.
HLA-A*11:01 (OR = 1.49 [1.18-1.87] P = 7.0*10-4), C*04:01 (OR = 1.34 [1.10-1.63] P = 3.23*10-3), and B*35:01 (OR=1.46 [1.13-1.89] P = 3.64*10-3) were associated with susceptibility to narcolepsy. Analysis of polymorphic class I amino-acids revealed even stronger associations with key antigen-binding residues HLA-A-Tyr9 (OR = 1.32 [1.15-1.52] P = 6.95*10-5) and HLA-C-Ser11 (OR=1.34 [1.15-1.57] P = 2.43*10-4).
Our findings provide a genetic basis for increased susceptibility to infectious factors or an immune cytotoxic mechanism in narcolepsy, potentially targeting hypocretin neurons.
[Show abstract][Hide abstract] ABSTRACT: The immune system is strongly implicated in the pathophysiology of multiple sclerosis (MS), as demonstrated by the efficacy of therapies targeting various components of adaptive immunity. However, the disease still progresses despite these treatments in many patients, while others experience life-threatening adverse effects, urging for the discovery of new immune-targeting medications. Among the immune cell types participating to MS pathogenesis, decades of work have highlighted the prominent role of CD4 T cells. More recent data demonstrate the involvement of CD8 T cells as well. The existence of both pathogenic and protective CD8 T cells subsets has been suggested, adding an additional layer of complexity to the picture. Mucosal-associated invariant T (MAIT) cells are innate-like lymphocytes that make up to 25% of CD8 T cells in healthy subjects. They are specific for conserved microbial ligands and may constitute an important barrier against invasive bacterial and fungal infection. An increasing number of reports also suggest their possible involvement in chronic inflammatory diseases, including MS. MAIT cells could participate through their ability to produce IFNγ and/or IL-17, two major cytokines in the pathogenesis of several chronic inflammatory/autoimmune diseases. However, the mechanisms by which MAIT cells could be activated in these sterile conditions are not known. Furthermore, contradictory observations have been made, reporting either a protective or a pro-inflammatory behavior of MAIT cells in MS or its murine model, experimental autoimmune encephalomyelitis. In this review article, we will describe the current knowledge on MAIT cell biology in health and disease, and discuss the possible mechanisms behind their role in MS. The specific features of this new non-conventional T cell subset make it an interesting candidate as a biomarker or as the target of immune-mediated intervention.
Full-text · Article · Sep 2015 · Frontiers in Immunology
[Show abstract][Hide abstract] ABSTRACT: Dendrimers are poly-functional nano-objects of perfectly defined structure that can provide innovative alternatives for the treatment of chronic inflammatory diseases, including multiple sclerosis (MS). To investigate the efficiency of a recently described amino-bis(methylene phosphonate)-capped ABP dendrimer as a potential drug candidate for MS, we used the classical mouse model of MOG35-55-induced experimental autoimmune encephalomyelitis (EAE). Our study provides evidence that the ABP dendrimer prevents the development of EAE and inhibits the progression of established disease with a comparable therapeutic benefit as the approved treatment Fingolimod. We also show that the ABP dendrimer redirects the pathogenic myelin-specific CD4+ T cell response towards IL-10 production.
No preview · Article · Sep 2015 · Biomacromolecules
[Show abstract][Hide abstract] ABSTRACT: Although CD8 T cells are key players in neuro-inflammation, little is known about their trafficking cues into the central nervous system (CNS). We used a murine model of CNS autoimmunity to define the molecules involved in cytotoxic CD8 T-cell migration into the CNS. Using a panel of monoclonal antibodies, we here show that the α4β1-integrin is essential for CD8 T-cell interaction with CNS endothelium. We also investigated which α4β1-integrin ligands expressed by endothelial cells are implicated. The blockade of vascular cell adhesion molecule-1 did not protect against autoimmune encephalomyelitis, and only partly decreased the CD8 T-cell infiltration into the CNS. In addition, inhibition of junctional adhesion molecule-B expressed by CNS endothelial cells also decreases CD8 T-cell infiltration. CD8 T cells may use additional and possibly unidentified adhesion molecules to gain access to the CNS. This article is protected by copyright. All rights reserved.
Full-text · Article · Sep 2015 · European Journal of Immunology
[Show abstract][Hide abstract] ABSTRACT: Central nervous system (CNS) inflammation occurs in a large number of neurological diseases. The type and magnitude of CNS inflammation, as well as the T-cell contribution, vary depending on the disease. Different animal models of neurological diseases have shown that T cells play an important role in CNS inflammation. Furthermore, recent studies of human neurological disorders have indicated a significant role for T cells in disease pathology. Nevertheless, how individual T-cell subsets affect neuronal survival, damage and/or loss remains largely unclear. In this review we discuss the processes by which T cells mediate either beneficial or deleterious effects within the CNS, with emphasis on the direct interaction between T cells and neurons, as occurs in multiple sclerosis, paraneoplastic cerebellar degeneration, and viral encephalitis. The therapeutic approaches targeting T cells and their mediators as treatment for neurological diseases are also described here. This article is protected by copyright. All rights reserved.
Full-text · Article · Sep 2015 · European Journal of Immunology
[Show abstract][Hide abstract] ABSTRACT: The implication of CD8 T cells in infectious and inflammatory diseases of the central nervous system has received increasing attention. CD8 T cells are crucial players of the adaptive immune system against neurotropic infections, but can also trigger tissue damage. Here we review the molecular mechanisms used by CD8 T cells to migrate into the central nervous system, and describe diseases that imply CD8 T cell-mediated pathogenicity. We also suggest therapeutic strategies targeting this population.
Full-text · Article · Sep 2015 · Medecine sciences: M/S
[Show abstract][Hide abstract] ABSTRACT: Lymphatic endothelial cells (LECs) directly express peripheral tissue antigens and induce CD8 T-cell deletional tolerance. LECs express MHC-II molecules, suggesting they might also tolerize CD4 T cells. We demonstrate that when β-galactosidase (β-gal) is expressed in LECs, β-gal-specific CD8 T cells undergo deletion via the PD-1/PD-L1 and LAG-3/MHC-II pathways. In contrast, LECs do not present endogenous β-gal in the context of MHC-II molecules to β-gal-specific CD4 T cells. Lack of presentation is independent of antigen localization, as membrane-bound haemagglutinin and I-Eα are also not presented by MHC-II molecules. LECs express invariant chain and cathepsin L, but not H2-M, suggesting that they cannot load endogenous antigenic peptides onto MHC-II molecules. Importantly, LECs transfer β-gal to dendritic cells, which subsequently present it to induce CD4 T-cell anergy. Therefore, LECs serve as an antigen reservoir for CD4 T-cell tolerance, and MHC-II molecules on LECs are used to induce CD8 T-cell tolerance via LAG-3.
[Show abstract][Hide abstract] ABSTRACT: Whereas preclinical investigations and clinical studies have established that CD8(+) T cells can profoundly affect cancer progression, the underlying mechanisms are still elusive. Challenging the prevalent view that the beneficial effect of CD8(+) T cells in cancer is solely attributable to their cytotoxic activity, several reports have indicated that the ability of CD8(+) T cells to promote tumor regression is dependent on their cytokine secretion profile and their ability to self-renew. Evidence has also shown that the tumor microenvironment can disarm CD8(+) T cell immunity, leading to the emergence of dysfunctional CD8(+) T cells. The existence of different types of CD8(+) T cells in cancer calls for a more precise definition of the CD8(+) T cell immune phenotypes in cancer and the abandonment of the generic terms "pro-tumor" and "antitumor." Based on recent studies investigating the functions of CD8(+) T cells in cancer, we here propose some guidelines to precisely define the functional states of CD8(+) T cells in cancer.
[Show abstract][Hide abstract] ABSTRACT: The discovery of hypocretins (orexins) and their causal implication in narcolepsy is the most important advance in sleep research and sleep medicine since the discovery of rapid eye movement sleep. Narcolepsy with cataplexy is caused by hypocretin defi ciency owing to destruction of most of the hypocretin-producing neurons in the hypothalamus. Ablation of hypocretin or hypocretin receptors also leads to narcolepsy phenotypes in animal models. Although the exact mechanism of hypocretin defi ciency is unknown, evidence from the past 20 years strongly favours an immune-mediated or autoimmune attack, targeting specifi cally hypocretin neurons in genetically predisposed individuals. These neurons form an extensive network of projections throughout the brain and show activity linked to motivational behaviours. The hypothesis that a targeted immune-mediated or autoimmune attack causes the specifi c degeneration of hypocretin neurons arose mainly through the discovery of genetic associations, fi rst with the HLA-DQB1*06:02 allele and then with the T-cell receptor α locus. Guided by these genetic fi ndings and now awaiting experimental testing are models of the possible immune mechanisms by which a specifi c and localised brain cell population could become targeted by T-cell subsets. Great hopes for the identifi cation of new targets for therapeutic intervention in narcolepsy also reside in the development of patient-derived induced pluripotent stem cell systems.
Full-text · Article · Mar 2015 · The Lancet Neurology
[Show abstract][Hide abstract] ABSTRACT: Therapeutic strategies that modulate the deleterious immune response underlying progressive multifocal leukoencephalopathy-associated immune reconstitution inflammatory syndrome (PML-IRIS) are warranted . Maraviroc, an antagonist of the CCR5 chemokine receptor that entered recently the HIV armamentarium, has been suggested to be beneficial in preventing or treating PML-IRIS [1, 4]. Since chemokine receptors play an important role in inflammatory cell migration, we investigated whether the molecular target of maraviroc is expressed on pathogenic T cells infiltrating PML-IRIS lesions. Paraffin-embedded brain specimens of inflammatory PML, obtained through diagnostic stereotactic brain biopsy, were analyzed from five previously described HIV-infected patients who developed PML-IRIS after initiation of antiretroviral therapy (ART) , and two non-HIV-infected patients who developed PML after chemotherapy or natalizumab, one who developed PML-IRIS, and the other at high risk of PML-IRIS ...
Full-text · Article · Jan 2015 · Acta Neuropathologica
[Show abstract][Hide abstract] ABSTRACT: During the past decades, anticancer immunotherapy has evolved from a promising therapeutic option to a robust clinical reality. Many immunotherapeutic regimens are now approved by the US Food and Drug Administration and the European Medicines Agency for use in cancer patients, and many others are being investigated as standalone therapeutic interventions or combined with conventional treatments in clinical studies. Immunotherapies may be subdivided into "passive" and "active" based on their ability to engage the host immune system against cancer. Since the anticancer activity of most passive immunotherapeutics (including tumor-targeting monoclonal antibodies) also relies on the host immune system, this classification does not properly reflect the complexity of the drug-host-tumor interaction. Alternatively, anticancer immunotherapeutics can be classified according to their antigen specificity. While some immunotherapies specifically target one (or a few) defined tumor-associated antigen(s), others operate in a relatively non-specific manner and boost natural or therapy-elicited anticancer immune responses of unknown and often broad specificity. Here, we propose a critical, integrated classification of anticancer immunotherapies and discuss the clinical relevance of these approaches.
[Show abstract][Hide abstract] ABSTRACT: Multiple sclerosis (MS), a demyelinating disease of the central nervous system (CNS), presents as a complex disease with variable clinical and pathological manifestations, involving different pathogenic pathways. Animal models, particularly experimental autoimmune encephalomyelitis (EAE), have been key to deciphering the pathophysiology of MS, although no single model can recapitulate the complexity and diversity of MS, or can, to date, integrate the diverse pathogenic pathways. Since the first EAE model was introduced decades ago, multiple classic (induced), spontaneous, and humanized EAE models have been developed, each recapitulating particular aspects of MS pathogenesis. The advances in technologies of genetic ablation and transgenesis in mice of C57BL/6J background and the development of myelin-oligodendrocyte glycoprotein (MOG)-induced EAE in C57BL/6J mice yielded several spontaneous and humanized EAE models, and resulted in a plethora of EAE models in which the role of specific genes or cell populations could be precisely interrogated, towards modeling specific pathways of MS pathogenesis/regulation in MS. Collectively, the numerous studies on the different EAE models contributed immensely to our basic understanding of cellular and molecular pathways in MS pathogenesis as well as to the development of therapeutic agents: several drugs available today as disease modifying treatments were developed from direct studies on EAE models, and many others were tested or validated in EAE. In this review, we discuss the contribution of major classic, spontaneous, and humanized EAE models to our understanding of MS pathophysiology and to insights leading to devising current and future therapies for this disease.
Full-text · Article · Aug 2014 · Journal of Autoimmunity
[Show abstract][Hide abstract] ABSTRACT: The recognition of multiple ligands by a single TCR is an intrinsic feature of T cell biology, with important consequences for physiological and pathological processes. Polyspecific T cells targeting distinct self-antigens have been identified in healthy individuals as well as in the context of autoimmunity. We have previously shown that the 2D2 TCR recognizes the myelin oligodendrocyte glycoprotein epitope (MOG)35-55 as well as an epitope within the axonal protein neurofilament medium (NF-M15-35) in H-2(b) mice. In this study, we assess whether this cross-reactivity is a common feature of the MOG35-55-specific T cell response. To this end, we analyzed the CD4 T cell response of MOG35-55-immunized C57BL/6 mice for cross-reactivity with NF-M15-35. Using Ag recall responses, we established that an important proportion of MOG35-55-specific CD4 T cells also responded to NF-M15-35 in all mice tested. To study the clonality of this response, we analyzed 22 MOG35-55-specific T cell hybridomas expressing distinct TCR. Seven hybridomas were found to cross-react with NF-M15-35. Using an alanine scan of NF-M18-30 and an in silico predictive model, we dissected the molecular basis of cross-reactivity between MOG35-55 and NF-M15-35. We established that NF-M F24, R26, and V27 proved important TCR contacts. Strikingly, the identified TCR contacts are conserved within MOG38-50. Our data indicate that due to linear sequence homology, part of the MOG35-55-specific T cell repertoire of all C57BL/6 mice also recognizes NF-M15-35, with potential implications for CNS autoimmunity.
Full-text · Article · Aug 2014 · The Journal of Immunology