IFN-β differentially regulates the function of T cell subsets in MS and EAE

Cytokine & Growth Factor Reviews 30 (2016) 47–54

Contents lists available at ScienceDirect

Cytokine & Growth Factor Reviews journal homepage: www.elsevier.com/locate/cytogfr

IFN-b differentially regulates the function of T cell subsets in MS and EAE Nadia Kavrochorianou* ,1, Melina Markogiannaki, Sylva Haralambous* Inflammation Research Group, Transgenic Technology Laboratory, Hellenic Pasteur Institute, Athens, Greece

A R T I C L E I N F O

A B S T R A C T

Article history: Received 29 February 2016 Accepted 21 March 2016 Available online 22 March 2016

Multiple sclerosis (MS) is considered as a T cell mediated autoimmune disease of the CNS, although a pathogenic role has also been attributed to other immune cell types as well as to environmental and genetic factors. Considering that T cells are interesting from an immunopathogenic point of view and consequently from a therapeutic perspective, various T cell targeted therapies have been approved for MS. Interferon beta (IFN-b) is widely used as first-line intervention for modulating T cell responses, although its pleiotropic and multifaceted activities influence its effectiveness on the disease development, with mechanisms that are not yet fully understood. Since different T cell populations, including pro-inflammatory and regulatory T cells, might affect the course of MS, the effects of IFN-b become even more complex. This review will summarize recent findings regarding the T cell targeted effect of IFN-b in MS and its animal model EAE, with emphasis on the direct actions of endogenous and exogenous IFN-b on each T cell subpopulation involved in CNS autoimmunity. Delineating how IFN-b exerts its action on different T cell types may eventually contribute to the designing of therapeutic strategies aiming to improve the effectiveness of this drug for MS treatment. ã 2016 Elsevier Ltd. All rights reserved.

Keywords: Multiple sclerosis Interferon beta T cell subsets Inflammation Experimental Autoimmune Encephalomyelitis

1. Introduction Multiple sclerosis (MS) is a chronic immune disease of the central nervous system (CNS), considered to be developed as a result of the breakdown of peripheral immune tolerance, thus

Abbreviations: APC, antigen-presenting cell; BBB, blood-brain barrier; CCR, C-C chemokine receptor; CNS, central nervous system; CSF, cerebrospinal fluid; CXCR, C-X-C chemokine receptor; EAE, experimental autoimmune encephalomyelitis; FoxA, forkhead box protein A; FOXP3, forkhead box P3; GITRL, glucocorticoidinduced TNF receptor-related protein; IFN, interferon; IFNAR, interferon receptor; IL, interleukin; IRF, interferon regulatory factor; LN, lymph nodes; MBP, myelin basic protein; MIP, macrophage inflammatory protein; MMP9, metalloproteinase-9; MOG, myelin oligodendrocyte glycoprotein; MS, multiple sclerosis; NAb, neutralizing antibody; NMO, neuromyelitis optica; PAMP, pathogen-associated molecular pattern; PBMC, peripheral blood mononuclear cell; pDC, plasmacytoid dendritic cell; PD-L, programmed death-ligand; PLP, proteolipid protein; PRR, pathogen recognition receptor; SOCS, suppressor of cytokine signaling; STAT, signal transducer and activator of transcription; Tfh, T follicular helper cell; Tfr, T follicular regulatory cell; Th, T helper cell; TNF, tumor necrosis factor; Tr1, type 1 regulatory cells; Treg, T regulatory cell; USP18, Ubiquitin specific peptidase 18; VLA4, very late antigen 4. * Corresponding authors. E-mail addresses: [email protected] (N. Kavrochorianou), [email protected] (S. Haralambous). 1 Current address: National and Kapodistrian University of Athens, School of Health Sciences, ICU Research Unit at “Agioi Anargyroi” General Hospital, Greece. http://dx.doi.org/10.1016/j.cytogfr.2016.03.013 1359-6101/ã 2016 Elsevier Ltd. All rights reserved.

leading to autoimmune attacks on CNS elements and eventually to neurodegeneration. The developing MS pathology includes visual disturbance, cognitive impairment and paralysis [1]. The pathogenesis of MS is complex and its etiology remains unknown, while several genetic, environmental and infectious factors (e.g. viruses) are proposed to be related with this disorder [2–4]. Nonetheless, T lymphocytes have been assumed to play a central role in the pathology of the disease, and MS is therefore considered as a classical T cell driven immune disease of the CNS [5]. The immune features of MS are well recapitulated by Experimental Autoimmune Encephalomyelitis (EAE), the most widely used animal model of the human disease, which is induced either by immunization with antigens derived from myelinspecific proteins of the CNS (active EAE), or by adoptive transfer of T cells from immunized mice to naïve recipients, in order to test the potential encephalitogenicity of the transferred cell population (passive EAE) [6]. Genome wide assay studies (GWAs) have revealed more than 100 potential MS risk-associated alleles with strong correlation to genes involved in immune functions, in particular T helper cell development or signaling [3]. Until now, there is no curative intervention for MS, although treatment options have been broadened during the last decades. Many of the currently approved therapies target T lymphocytes either directly (e.g. natalizumab, fingolimod) or indirectly via

", significantly higher: #, significantly lower, compared to control groups.

Type I IFNs are used for the treatment of a wide range of diseases, and particularly IFN-b as a first-line intervention for MS [22]. Although IFN-b is an important therapeutic approach, several side effects, limited activity required by patients and its failure to control the progressive forms of MS have been reported [23].

" IL-10 production by splenocytes [28] " IL-10 and " IL-10 mRNA levels in PLP-specific T cells and IL-10 protein in PLP- Foxp3 mRNA levels in serum and CSF [80] primed LN cells [40] " Treg proliferation [72]

# IL17 production by MOG-primed LN cells [28] # IL17 mRNA levels in spleen and LN cells [37,64] # Frequency of CD4+ IL-17+ cells in the brain [38] " Production of IL-27 by DCs [38] # Expression of Th17 chemokines and their receptors on CD4+ T cells in the CNS [54] # IL-17 production by MOG-primed splenocytes [51] # Frequency of CD4+ IL-17+ LN cells on day 4 of EAE [58] # Frequency of CD4+ IL-17+ and CD4+ CCR6+ splenocytes and IL17 production on day 10 of EAE [62] Th17

2.2. IFN-b: as first-line intervention for MS

Table 1 The effect of IFN-b on prominent T cell subsets in EAE and MS.

2.1. IFN-b: production, signaling and regulation

Tregs

# Th1 infiltration in CNS [53] # Expression of Th1 chemokines and their receptors on CD4+ T in the CNS [54] # IFN-g production by Th1 cells [53] # IFN-g production by MOG-primed splenocytes [51] Th1

2. Properties of IFN-b and its relevance to MS

Interferons (IFNs) were firstly described for their ability to interfere with and inhibit viral replication [12]. Soon after, more activities such as antiproliferative, antitumoral and immunoregulatory, were also acknowledged [13]. Based on the type of receptor they ligate, IFNs are classified in three categories; type I, type II and type III IFNs. Type I IFNs signal through a heterodimeric receptor, the IFN alpha receptor (IFNAR), composed of two subunits, IFNAR1 and IFNAR2, which are expressed in almost every cell type [14,15]. Type I IFN family comprises various members, but the most well defined IFN-a and IFN-b possess strong antiviral and immunomodulatory properties and regulate homeostatic processes [16,17]. Upon engagement of Pathogen Recognition Receptors (PRR) by pathogen-associated molecular patterns (PAMPs), several Interferon Regulatory Factors (IRFs) are activated, leading to type I IFNs synthesis [18]. Plasmacytoid dendritic cells (pDCs) are reportedly the main producers of type I IFNs [19]. Although there is evidence that type I IFNs trigger many different signaling pathways, the JAK-STAT pathway is the most well-defined [14]. Downstream of the signaling pathways, numerous IFN-stimulated genes (ISGs) are expressed, contributing to the various effects of type I IFNs stimulation [14,20]. Noteworthy, the signaling pathway initiated by type I IFNs may largely differ depending on the cell type they stimulate, the cell activation status and the density of IFNAR on the cell surface [21]. Furthermore, type I IFN signaling pathway may be suppressed by the induction of negative regulators (e.g. SOCS and USP18) and miRNAs [10]. This complexity may, in part, explain the conflicting results regarding the pleiotropic actions of type I IFNs in different contexts [20].

# IL-17A and IL-17F production by CD4+ T cells in PBMCs [63]

MS

Endogenous IFN-b Exogenous IFN-b Endogenous IFN-b

Exogenous IFN-b

broad effects on the immune system (e.g. glatiramer acetate, interferon beta) [7,8]. Moreover, T cell depletion approaches were also evaluated, unfortunately without success. Anti-CD3- (Muromonab) and anti-CD4-directed therapies (Priliximab) failed to show efficacy in humans, had limited therapeutic potential and/or exerted serious adverse effects [7]. Since interferon beta (IFN-b) preserves its long-term safety and efficacy, it is widely used as first-line treatment for MS. Metaanalysis of clinical trials indicates that IFN-b reduces MS relapses and attenuates novel inflammatory lesions, although many patients do not respond to the treatment [9]. Responses to IFNb are shown to be cell type-, dose- and context- dependent, shaping its role (anti- or pro-inflammatory) during the different phases of an immune response [10,11]. The current review discusses the impact of T cell dysfunction on CNS autoimmunity and highlights the pleiotropic actions of IFN-b on various T cell subpopulations during the course of the disease. We believe that extensive preclinical research on T cellassociated IFN-b-mediated mechanisms of action in EAE and MS is of great interest, as it can provide new insights towards meaningful clinical approaches for MS patients.

# Expression of T-bet and IFN-g genes in the blood [43] # CCR5 mRNA levels and its ligands on T cells [56] " CCR5, IL-12Rb2 and IFN-g mRNA levels in PBMCs [57] # Th17 cells differentiation in PBMCs [61,65] # IL-17 mRNA and protein levels in PBMCs [66,67] # Proportion of IL-17A+ and IL-17F+ CD4+ T cells in PBMCs [63] # Expression of IL17C and IL23R genes in PBMCs [63] " Treg function and proportion in peripheral blood [73] " IL-10 mRNA and protein levels in PBMCs [40,82] " IL-10 production by CD4+ T cells in PBMCs [65] " IL-10+ cells in PBMCs [67,80] " IL-10 mRNA and protein levels in CSF [67,80]

N. Kavrochorianou et al. / Cytokine & Growth Factor Reviews 30 (2016) 47–54

EAE

48

N. Kavrochorianou et al. / Cytokine & Growth Factor Reviews 30 (2016) 47–54

Although the precise underlying mechanisms are not yet elucidated, the immunomodulatory effects of IFN-b are exerted in a variable rather than in a Tcell selective and specific manner [24,25]. Cumulative data obtained from various in vitro and in vivo systems, indicate that IFN-b treatment beneficially affects MS patients by acting at different levels of the immune response; by increasing anti-inflammatory cytokines production, such as IL-4 and IL-10, decreasing pro-inflammatory cytokines production, such as IL-17, IL-23, osteopontin, IFN-g and TNF-a, inducing apoptosis of autoreactive T cells, decreasing leukocyte migration across the blood-brain barrier (BBB), and modulating the function of regulatory T cells (Tregs), while inducing expansion of naïve Treg populations [24]. Although treatment with IFN-b is commonly used for controlling exacerbations and progression in MS, several adverse events, partial efficacy, or even exacerbation of the disease have been reported [23]. These discrepancies may be attributed to several reasons, such as the production of neutralizing antibodies (NAbs) [26] and/or the elevated levels of endogenous IFN-b and its gene products prior to initiation of treatment [27]. Nonetheless, IFNbefficacy seems to be altered by the profile of encephalitogenic T helper cells; IFN-b alleviates symptoms in conditions with Th1 bias, whereas it promotes pathology in Th17 mediated disease [28,29]. Finally, it was recently suggested that high levels of serum IL-17F above a threshold prior to IFN-b treatment may also be responsible for the non-responsiveness of MS patients [29,30]. Therefore, in order to improve therapeutic approaches, it is imperative to understand how IFN-b exerts its multifaceted actions on different cell types involved in MS. Towards this direction we next summarize IFN-b effects on the most prominent T cell subpopulations (Table 1, Fig. 1).

49

3. Effects of IFN-b on T cell subsets involved in EAE and MS 3.1. CD4+ T cells CD4+T cell population consists of distinct cell subsets, including Th1, Th2, Th17, regulatory T cells (Tregs) and T follicular helper cells (Tfh), all characterized by specific functions and gene expression profiles but also by plasticity depending on the context [31,32]. Traditionally, CD4+ T cells reactive against myelin antigens are considered to be encephalitogenic and to lead the immune cascade that results in CNS autoimmunity. Therefore, the factors that regulate their differentiation into effector subtypes, and that affect their pathogenic potential have been extensively studied. How these T cell subpopulations contribute to EAE and MS immunopathogenesis has been reviewed previously [33,34]. The direct and indirect effect of IFN-b on T cell functions has been investigated under physiological or pathological conditions, often generating contradictory results, mainly due to differences in experimental settings used. Under normal conditions, using ifnb/ mice, endogenous IFNbwas shown to decrease lymph node (LN) cell proliferation upon aCD3 stimulation [35], while it was later demonstrated to induce T cell proliferation, by acting on dendritic cells [36]. Moreover, exogenously administered IFN-b is reported to directly reduce CD4+ T cell proliferation upon aCD3/aCD28 stimulation in both mouse and human studies [37,38]. Furthermore, IFN-b reduced matrix metalloproteinase-9 (MMP9) expression on healthy human T cells in vivo and inhibited T cell transmigration into the CNS ex vivo [39]. In CNS autoimmunity, the actions of IFN-b on T cells have been described in several studies. In passive EAE experiments, exogenous IFN-b was shown to impair the encephalitogenicity of PLP- and MBP- specific T cells [40], although such effect was not reported when ifnb/ mice were used [41]. Furthermore, IFN-b

Fig. 1. Schematic representation of IFN-b effects on the most prominent T cell subsets implicated in MS and EAE. IFN-b regulates T cell function via directly and indirectly modulating the expression of transcription factors that drive T cell differentiation, the production of effector cytokines by T cells, the expression of adhesion molecules and chemokine receptors on their surface as well as their functionality at different levels. IFN-b directly inhibits Th1 responses, by decreasing Th1-associated cytokines production, reducing VLA4 and CCR5 levels of on Th1 surface and decreasing their capacity to transfer EAE to naive recipients; IFN-b directly suppresses Th17 responses, by reducing Rorc expression in and IL-17 production by Th17 cells, and by decreasing the expression of CCR6 and IL-23R on their surface; IFN-b directly enhances IL-10 production by Tregs or other IL-10 producing T helper cells, possibly Tr1 cells. ?: potential mediator cell of IFN-b indirect effect on T helper cells

50

N. Kavrochorianou et al. / Cytokine & Growth Factor Reviews 30 (2016) 47–54

suppressed T cell effector function in the CNS indirectly, by acting on glial cells, the antigen presenting cell type of the CNS [42]. In human disease, CD4+ T cells isolated from IFN-b treated MS patients were reported to display decreased MBP-induced proliferation ex vivo [43], while VLA4 expression on the surface of CD4+T cells was also reduced in the same setting [44,45]. 3.2. Pro- versus anti- inflammatory CD4+ T cell subsets In CNS autoimmunity the imbalance between pro- and antiinflammatory events contributes to immunopathogenesis. The prevailing view from late 1980s was based on the Th1/Th2 paradigm according to which, Th1 cells were the main pathogenic T cell subtype in EAE and MS, while Th2 cells were the anti-inflammatory T cell subset. However, this paradigm could not explain all aspects of the disease [46]. After many years of intense research in the field, in 2005, a new pathogenic T cell lineage, Th17, evidenced to play a crucial role in many inflammatory diseases, including EAE and MS. The current view supports the idea that Th17cells play an essential role mainly in the initial phases of the disease, while Th1 cells have a more pronounced role later on [47]. On the other hand, regulatory mechanisms have evolved to suppress self-reactive T cell specificities that escaped central tolerance and this role was attributed to regulatory T cells (Tregs) [48,49]. The effects of IFN-b on each of these T cell subtypes will be the focus of the following sections. 3.2.1. Th1 cells Since IFN-gproducing Th1 cells were proved to be pathogenic in inflammatory conditions, such as EAE and MS, how IFN-b modulates Th1 responses in health and disease has been evaluated. In normal conditions, using ifnar1/ mice, endogenously produced type I IFNs were shown to upregulate IFN-g production by ovalbumin-specific (OT-II) T cells, upon stimulation with OT-II peptide [50]. On the other hand, the effect of exogenous IFN-b on Th1 cells in health has been extensively studied. Although IFN-b treatment of splenocytes or purified CD4+ T cells was reported to increase the proportion of CD4+IFN-g+ cells [28], Sweeney et al. demonstrated that activated PBMCs-derived CD4+ T cells from healthy donors and treated with IFN-b, produced less IFN-g compared to non IFN-b treated samples [38]. Regarding the role of endogenously produced type I IFNs on Th1 cells in CNS autoimmunity, the studies are inconclusive too. While Guo et al. reported that ifnar1/ MOG restimulated splenocytes produced higher amount of IFN-g [51], Prinz et al. detected no difference in a similar setting [52]. In accordance with the latter study, Teige et al. demonstrated that LN cells from ifnb/ EAE mice, restimulated with MOG ex vivo, produced same amount of IFN-g with LN cells from WT mice [41]. Moreover, it was recently suggested that exogenous IFN-b can directly suppress in vitro IFN-g production by Th1 cells in EAE partly due to the induction of the negative regulatory receptor TIM-3 on effector Th1 cells [53]. Apart from their capacity to produce IFN-g, Th1 cells also express characteristic chemokine receptors, such as CCR5 and CXCR3 [54]. A recent study demonstrated that, in vivo treatment with IFN-b during EAE decreased the absolute numbers of infiltrated CD4+ T cells expressing these receptors, along with reduced Th1 migration into the CNS [54]. Furthermore, IFN-b is shown to directly impair the encephalitogenicity of Th1 cells, since they are not capable to induce EAE when transferred into Rag1/ mice [53]. Along with animal studies, numerous MS studies have investigated the effect of IFN-b treatment on Th1 responses. On the one side, IFN-b is shown to suppress Th1 cells. Specifically, in vitro treatment of PBMCs from MS patients with IFN-b led to

decreased cell proliferation and IFN-g production [55]. Accordingly, the gene expression of transcription factor T-bet, as well as IFN-g, both Th1 cell-associated markers, was reduced in the blood from IFN-b treated MS patients [43]. Although in the aforementioned studies, the observed effect could be a result of IFN-b action on bystander cells, a direct effect on Th1 cells was previously demonstrated by Zang et al.; IFN-b treatment of T cells isolated from the blood of MS patients led to lower mRNA levels of CCR5 and its ligands, RANTES and MIP-1a compared to non IFN-b treated samples [56]. In the same study, similar results were reported in vivo upon IFN-b treatment of MS patients [56]. On the other side, several studies suggest that the effects of IFN-b are not only anti-inflammatory but also pro-inflammatory. Specifically Wandinger et al. detected increased mRNA levels of Th1 markers, CCR5, IL-12Rb2 and IFN-g in PBMCs from MS patients, upon treatment with IFN-b in vitro and in vivo [57]. 3.2.2. Th17 cells A number of studies have highlighted the central role of Th17 cells in the development and pathogenesis of EAE and MS and therefore the action of IFN-b on Th17 responses in health and disease has been examined. Using ifnb/mice, Galligan et al. demonstrated that endogenous IFN-b reduces the percentage of CD4+IL-17+ cells upon stimulation of splenocytes with aCD3/aCD28, although it was unclear whether this was a direct effect on T cells or via modulation of APCs [58]. On the contrary, making use of ifnar1/ mice, endogenously produced type I IFNs were shown to act on dendritic cells, in order to upregulate IL-17 production by OT-II T cells, upon stimulation with OT-II peptide [50]. In a similar setting, Pennell et al. recently reported a direct effect of endogenous IFN-b on sorted mouse CD4+ T cells, decreasing IL-17 production upon stimulation with aCD3/aCD28 [59]. Regarding the role of exogenously administered IFN-b in normal conditions, several studies draw no conclusion in the context of its direct or indirect effect on Th17 cells. Axtell et al. found that IFN-b administration reduced IL-17 production by Th17 polarized CD4+ T cells indirectly, via its effect on APCs [28]. However, a direct effect of IFN-b on T cells was reported recently, showing that, exogenous IFN-b reduced the production of IL-17 by Th17 polarized CD4+ T cells in a dose-dependent manner, as well as the proportion of CD4+IL-17+ cells [60]. In agreement with this study, Durelli et al. showed that exogenous IFN-b directly inhibited Th17 response of Th17 polarized human CD4+ T cells [61]. This study also revealed that IFN-b administration led to increased apoptosis of Th17 polarized PBMCs from healthy donors, without clarifying though whether Th17 cells were the direct target of IFNb. In line with these results, exogenous IFN-b reduced IL-17 mRNA and protein levels in stimulated mouse CD4+ T cells in vitro, indicating a direct effect on T cells [37], while similar results were obtained in human PBMC derived CD4+ T cells [38]. Apart from the plenty of studies on the role of IFN-b on Th17 differentiation in health, its effect on Th17 responses during EAE and MS was also extensively investigated. Using ifnar1/ mice, Prinz et al. demonstrated that endogenous type I IFNs did not alter IL-17 production by LN cells from EAE mice [52]. On the contrary, MOG restimulated splenocytes from ifnar1/ EAE mice secreted higher levels of IL-17, indicating that endogenous type I IFNs could affect IL-17 production in this specific context, although this effect could not be attributed to T cells directly [51]. A study performed during the disease course pointed out that endogenous IFN-b reduces the frequency of CD4+IL-17+ LN cells isolated on day 4 of EAE, but this effect was not observed on day 10 [58]. A recent study by our group, using ifnar1Tecxl mice that express IFNAR selectively on T cells, showed that endogenous IFN-b acted directly on T cells in vivo, reducing Th17 responses in the periphery on day

N. Kavrochorianou et al. / Cytokine & Growth Factor Reviews 30 (2016) 47–54

10 of EAE, but this effect was reversed on day 17 [62]. In addition, silencing of irf7, a factor that mediates IFN-b production, in CD4+ T cells from MS patients, led to secretion of higher levels of IL-17A and IL-17F, suggesting that endogenous IFN-b suppressed Th17 responses [63]. Besides the role of endogenous IFN-b in EAE and MS, exogenous IFN-b decreased IL-17 production by MOG-primed LN cells in vitro [28] and lessened IL-17 mRNA levels in LN and spleen cells from EAE mice [37,64]. In accordance with these results, Sweeney et al. detected lower frequency of CD4+IL-17+ cells in the brain of EAE mice, treated daily with recombinant IFN-b, accompanied by increased levels of IL-27 [38]. Furthermore, in vivo treatment with IFN-b during EAE significantly reduced the absolute numbers of CD4+ T cells expressing the Th17 characteristic chemokine receptors CCR2, CCR4 and CCR6 in the CNS, indicating that IFN-b decreases Th17 cell infiltration into the CNS [54]. Similar to animal studies, in vitro administration of IFN-b in CD4+ T cells from MS patients directly impaired Th17 cell differentiation, as evidenced by decreased RORc, IL23R and CCR6 levels [61,65]. Accordingly, IFN-b treatment of PBMCs from MS patients also lessened IL-17 mRNA and protein levels, but whether this effect was direct on T cells was not addressed in this study [66]. Recently, Kvarnström performed a longitudinal study and reported that IFN-b treatment of MS patients for one year decreased IL-17 production by PBMCs [67]. Additionally, IFN-b reduced in vitro the proportion of CD4+ IL-17A+ and CD4+ IL-17F+ T cells from MS patients’ PBMCs, while decreased in vivo gene expression of IL-17C and IL-23R in PBMCs from IFN-b treated MS patients [63]. Conclusively, IFN-b does indeed inhibit IL-17 production in vitro and in vivo, in animal and human studies, acting directly or indirectly on T cells. Noteworthy, IFN-b treatment was found to exacerbate Th17-mediated EAE [28]. In favor to this study, there are data reporting that IFN-b may be detrimental in other Th17 conditions, such as psoriasis and neuromyelitis optica (NMO) [68,69] and the underlying pathomechanism definitely requires further investigation. 3.2.3. Regulatory T cells (Tregs) An important CD4+ T cell subpopulation that contributes to immune homeostasis exhibiting anti-inflammatory activities and maintaining peripheral tolerance is the regulatory T cells. Several classes of Tregs have now been identified, including the naturally occurring CD4+CD25+Foxp3+Tregs (nTregs), and the induced Tregs (iTregs), including IL-10-producing Tr1 and TGF-b-producing Th3 cells [70]. In chronic inflammation, where the inflammatory environment dominates, Tregs are unable to reverse the imbalance between proand anti-inflammatory responses. This phenomenon may be due to inadequate numbers of Tregs, to intrinsic defects in their function and also to resistance of pathogenic effector T cells to Treg-induced suppression [71]. Under normal conditions, in vitro treatment of nTregs with IFNb prior to co-culture with naïve CD4+ T cells led to higher suppressive activity, as evaluated by cell proliferation [37]. In EAE experiments, in vivo administration of IFN-b promoted proliferation of Tregs via GITRL up-regulation on dendritic cells [72], thus the efficacy of IFN-b therapy may rely on the indirect enhancement of Treg proliferation. Moreover, in MS patients, IFN-b treatment has been associated with higher Treg frequency and enforced suppressive capacity, as well as with an increase in Foxp3 mRNA levels in sorted CD4+ CD25+ circulating cells [43,73]. On the contrary, an increase in Treg frequency was not observed in other studies [74,75]. Except for the already described classic Tregs, a subset of CD4+ T cells that express PD-L1high and differentiate under the

51

FoxA1 transcription factor, was recently identified and termed FoxA1+ Tregs [76]. Such Tregs developed in the CNS of EAE mice in an IFN-b- and IFNAR-dependent fashion. Nonetheless, human FoxA1+Treg were not only induced in vitro upon treatment of PBMCs with IFN-b, but also detected in peripheral blood from successfully treated with IFN-b MS patients [76]. Another subset of Tregs that possess impaired suppressive capacity in MS patients is the inducible IL-10 producing Tr1 cells [70,77]. IL-10 is a potential anti-inflammatory cytokine and numerous studies have revealed its importance in regulating EAE [78,79]. To our knowledge there are no data available concerning the effect of IFN-b on Tr1 cells, whereas the effect of IFN-b on IL-10 production has been extensively studied in mice and humans. It is evident that in normal conditions IFNbtreatment of mouse splenocytes or human PBMCs increased the levels of IL-10 mRNA and protein [28,40,80,81]. However, this action was not directly exerted on T cells, but rather on bystander monocytes and APCs [28,38]. On the contrary, treatment of Th17 polarized CD4+ T cells with IFN-b augmented IL-10 production and this effect was directly exerted on CD4+ T cells [60]. Not only in health, but also in CNS autoimmunity IFN-b is shown to enhance IL-10 release. Interestingly, a proportion of untreated MS patients demonstrate increased spontaneous expression of IFN-b inducible genes and this expression was correlated with increased expression levels of IL-10 and Foxp3 mRNA, indicating that endogenous IFN-b may induce the expression of immunoregulatory IL-10 in vivo [80]. In addition, stimulation of PLP-specific T cells with IFN-b in vitro led to elevated levels of IL-10 mRNA and protein [40], while IFN-b administration in EAE mice increased IL-10 production by total splenocytes [28]. Regarding the human disease, in vitro treatment of PBMCs from MS patients with IFN-b enhanced the expression of IL-10 mRNA and protein [40,82]. Moreover, IFN-b administered to MS patients augmented IL-10 mRNA and protein levels in serum and CSF [67,80]. A very important finding was that, although previous studies did not identify whether the effect of IFN-b was direct on T cells or mediated via modulation of bystander cells, Ramgolam et al. detected a direct increase of IL-10 production by CD4+ T cells, isolated from MS patients and treated with IFN-bin vitro [65]. In light of recent findings, another Tregs subset, highly expressed in MS patients, is the IFN-g producing Treg population. Notably, treatment of MS patients with IFN-b reduced the percentage of IFN-g+Foxp3+ T cells to levels similar to those of healthy controls [83], although this effect needs verification. 3.3. Other T cell subpopulations implicated in EAE and MS Apart from Th1, Th17 and Tregs, more T cell subsets are reportedly involved in CNS autoimmunity, such as IL-17+ IFNg+ T cells, CD8+ T cells, CD8+ Tregs, gd T cells, NKT cells, T follicular helper (Tfh) cells, T follicular regulatory (Tfr) cells and others. In order to have an overview of the data related to the contribution of these T cell subtypes in EAE and MS, in this section we will present available related data to date, although to our knowledge, limited number of reports have studied the impact of IFN-b on these T cell subpopulations. 3.3.1. IL-17+ IFN-g + T cells T cells producing both IL-17 and IFN-g, and express T-bet and RORgt, have been detected in the CNS during EAE [84]. Nonetheless, a recent human study identified an enrichment of T cells expressing both IL-17 and IFN-g in MS brain tissue [85,86]. Although Th1 and Th17 cells are reported to transmigrate through the BBB, IL-17+ IFN-g+ T cells appear to cross the BBB more efficiently in MS patients, fingering that this T cell subpopulation

52

N. Kavrochorianou et al. / Cytokine & Growth Factor Reviews 30 (2016) 47–54

may have higher encephalitogenic capacity [85]. Interestingly, these T cells were found to infiltrate the CNS prior to the onset of clinical symptoms of EAE, and may mediate CNS inflammation, partly, through microglial activation [47]. Although the effect of IFN-b on IL-17+ IFN-g+ T cells is least examined, it was recently shown that daily IFN-b administration during EAE leads to attenuated disease, along with reduced numbers of IL-17+ IFN-g+ T cells in the brain [38]. The potential encephalitogenicity of this T cell subpopulation, as well as where (periphery or CNS) and how IFN-b modulates the function of this T cell subset, need further investigation. 3.3.2. CD8+ T cells In the context of effector functions, cytotoxic CD8+ T cells are better suited to mediate CNS damage, since they can directly lyse neurons via FAS/FASL-mediated death [87]. Hence, CD8+ T cells are more prevalent in active lesions of MS brain tissue than are CD4+ T cells [88] and CD8+ cytotoxic Tcell response to MBP is increased in MS patients [5]. Interestingly, Lossius et al. reported the presence of EBVspecific CD8+ T cells in the CSF of MS patients [89], and this enrichment has been associated with MRI-based tissue damage [90]. Treatment of MS patients with IFN-b is shown to reduce the frequency of VLA4+ CD8+ T cells among total PBMCs, as well as VLA4 surface expression [44]. Similar results were obtained upon MOG stimulation of PBMCs from IFN-b-treated MS patients, where decreased frequencies of CD8+ and CD8+IFN-g+ T cells were observed [91]. 3.3.3. gd T cells Unlike conventional T cells, gd T cells recognize non-peptide antigens and produce cytokines influencing adaptive immune responses. Their role in autoimmune diseases has been thoroughly reviewed recently [92]. A very important finding was that gd T cells express CCR6 on their surface and can produce IL-17, raising the possibility that gd T cell-derived IL-17 may contribute to CNS pathology [93,94]. Although the consensus from various studies favors a pathogenic role for gd T cells in EAE [95], they may also have a preventive role during disease resolution, as indicated using gd T cell deficient mice or an antibody against gd TCR [96,97]. The exact mode of action of gd T cells in EAE and MS and moreover the effect of IFN-b on their functionality, require further investigation, in order to include them in the list of potential MS targets [98]. 3.3.4. T follicular helper cells (Tfh) and T follicular regulatory cells (Tfr) Tfh cells, a CD4+T cell subset essential for the generation of high affinity memory B cells in the germinal centers, are recently considered to implicate in the pathogenesis of MS [99]. In addition, a new Tfr cell subtype that participates in maintenance of selftolerance in the germinal centers, has been identified [100]. Dhaeze et al. recently showed that circulating Tfr cells in MS patients were functionally impaired, since lower frequency thereof and reduced suppressive capacity on T effector cell proliferation were recorded [101]. The contribution of Tfh and Tfr cells to EAE and MS remains to be verified, and if so, the impact of IFN-b on their function needs to be analyzed. 4. Concluding remarks The immunomodulatory IFN-b is used as first-line treatment for MS, but its pleiotropic effects on almost every cell may be responsible for the differential effectiveness of the drug and the adverse effects observed. Similarly, the effect of IFN-b on different subtypes of the same population may also variously regulates the disease outcome.

This review briefly discussed the dysregulation of main T cell subpopulations in CNS autoimmunity and summarized the T cell targeted effects of endogenous and exogenous IFN-b in health and EAE/MS, with emphasis on the direct actions of IFN-b on each T cell subset involved in the disease. Conclusively, due to ubiquitous expression of IFNAR, only few findings are related to the direct effect of IFN-b on T cells, especially in in vivo conditions, where the studying of T cell biology is more complex. Noteworthy, there are only two studies that reveal this specified action, using two different transgenic mouse models. Prinz et al. generated ifnar1fl/ fl CD4Cre mice that lack IFNAR on T cells [52], while our group reversely generated IFNAR1Texcl mice that express IFNAR exclusively on T cells [62]. These two different approaches enriched our knowledge on the beneficial effect of IFN-b on T cells and its dependence on the cellular environment and disease stage. An important feature of T cells is their plasticity, i.e. their capacity to convert into diverse T subtypes, depending on the cellular environment and cytokine milieu [32]. Since IFN-b affects many functional characteristics of T cell subsets both in health and disease, it would be important to investigate the effect of IFN-b on the T helper cell plasticity, which thereafter may affect the course of EAE and MS. Thorough investigation of the molecular mechanisms that underlie the beneficial effects of type I IFNs on each T cell subtype would be crucial for understanding the possibility of designing novel customized IFN-b-based therapies that selectively target and manipulate specific T cell subpopulation, thus possibly improving existing therapeutic interventions in MS. Acknowledgements This work was performed in the context of the InfeNeuTra project, part of the KRIPIS action, with Code Number MIS 450598, funded by the General Secretariat of Research & Technology (GSRT); the entire action was co-funded by Greece and the European Regional Development Fund of the European Union through Operational Program Competitiveness and Entrepreneurship of the National Strategic Reference Framework (NSRF) 2007–2013. The project was also partly supported by the Transgenic Technology Unit (TTU) of Hellenic Pasteur Institute. References [1] J. Goverman, Autoimmune T cell responses in the central nervous system, Nat. Rev. Immunol. 9 (2009) 393–407. [2] G.C. Ebers, Environmental factors and multiple sclerosis, Lancet Neurol. 7 (2008) 268–277. [3] A.H. Beecham, N.A. Patsopoulos, D.K. Xifara, M.F. Davis, A. Kemppinen, C. Cotsapas, et al., Analysis of immune-related loci identifies 48 new susceptibility variants for multiple sclerosis, Nat. Genet. 45 (2013) 1353– 1360. [4] J.D. Lünemann, C. Münz, EBV in MS: guilty by association? Trends Immunol. 30 (2009) 243–248. [5] M. Sospedra, R. Martin, Immunology of multiple sclerosis, Annu. Rev. Immunol. 23 (2005) 683–747. [6] M. Rangachari, V.K. Kuchroo, Using EAE to better understand principles of immune function and autoimmune pathology, J. Autoimmun. 45 (2013) 31– 39. [7] S. Bittner, H. Wiendl, Neuroimmunotherapies targeting T cells: from pathophysiology to therapeutic applications, Neurotherapeutics 13 (2015) 4– 19. [8] L. Tuosto, Targeting Inflammatory T Cells in Multiple Sclerosis: Current Therapies and Future Challenges, Austin J. Mult. Scler. & Neuroimmunol. 2 (2015) 1–9. [9] S. Nikfar, R. Rahimi, M. Abdollahi, A meta-analysis of the efficacy and tolerability of interferon-b in multiple sclerosis, overall and by drug and disease type, Clin. Ther. 32 (2010) 1871–1888. [10] L.B. Ivashkiv, L.T. Donlin, Regulation of type I interferon responses, Nat. Rev. Immunol. 14 (2014) 36–49. [11] A.H.H. van Boxel-Dezaire, M.R.S. Rani, G.R. Stark, Complex modulation of cell type-specific signaling in response to type I interferons, Immunity 25 (2006) 361–372.

N. Kavrochorianou et al. / Cytokine & Growth Factor Reviews 30 (2016) 47–54 [12] A. Isaacs, J. Lindenmann, Virus interference. I. The interferon, Proc. R. Soc. Lond. B Biol. Sci. 147 (1957) 258–267. [13] A.N. Theofilopoulos, R. Baccala, B. Beutler, D.H. Kono, Type I interferons (alpha/beta) in immunity and autoimmunity, Annu. Rev. Immunol. 23 (2005) 307–336. [14] L.C. Platanias, Mechanisms of type-I- and type-II-interferon-mediated signalling, Nat. Rev. Immunol. 5 (2005) 375–386. [15] G. Uzé, G. Schreiber, J. Piehler, S. Pellegrini, The receptor of the type I interferon family, Curr. Top. Microbiol. Immunol. 316 (2007) 71–95. [16] I. Gresser, Biologic effects of interferons, J. Invest. Dermatol. 95 (1990) 66S– 71S. [17] D.J. Gough, N.L. Messina, C.J.P. Clarke, R.W. Johnstone, D.E. Levy, Constitutive type I interferon modulates homeostatic balance through tonic signaling, Immunity 36 (2012) 166–174. [18] P.J. Hertzog, Overview. Type I interferons as primers, activators and inhibitors of innate and adaptive immune responses, Immunol. Cell Biol. 90 (2012) 471– 473. [19] G. Grouard, M.C. Rissoan, L. Filgueira, I. Durand, J. Banchereau, Y.J. Liu, The enigmatic plasmacytoid T cells develop into dendritic cells with interleukin (IL)-3 and CD40-ligand, J. Exp. Med. 185 (1997) 1101–1111. [20] J.M. González-Navajas, J. Lee, M. David, E. Raz, Immunomodulatory functions of type I interferons, Nat. Rev. Immunol. 12 (2012) 125–135. [21] S.Y. Fuchs, Hope and fear for interferon: the receptor-centric outlook on the future of interferon therapy, J. Interferon Cytokine Res. 33 (2013) 211–225. [22] D.W. Paty, D.K. Li, Interferon beta-1b is effective in relapsing-remitting multiple sclerosis. II. MRI analysis results of a multicenter randomized, double-blind, placebo-controlled trial. UBC MS/MRI Study Group and the IFNB Multiple Sclerosis Study Group, Neurology 43 (1993) 662–667. [23] Y. Warabi, Y. Matsumoto, H. Hayashi, Interferon beta-1b exacerbates multiple sclerosis with severe optic nerve and spinal cord demyelination, J. Neurol. Sci. 252 (2007) 57–61. [24] S. Dhib-Jalbut, S. Marks, Interferon-b mechanisms of action in multiple sclerosis, Neurology 74 (2010). [25] B.C. Kieseier, The mechanism of action of interferon-b in relapsing multiple sclerosis, CNS Drugs 25 (2011) 491–502. [26] H. Hegen, M. Schleiser, C. Gneiss, F. Di Pauli, R. Ehling, B. Kuenz, et al., Persistency of neutralizing antibodies depends on titer and interferon-beta preparation, Mult. Scler. 18 (2012) 610–615. [27] M. Comabella, D.W. Craig, C. Morcillo-Suárez, J. Río, A. Navarro, M. Fernández, et al., Genome-wide scan of 500,000 single-nucleotide polymorphisms among responders and nonresponders to interferon beta therapy in multiple sclerosis, Arch. Neurol. 66 (2009) 972–978. [28] R.C. Axtell, B.A. de Jong, K. Boniface, L.F. van der Voort, R. Bhat, P. De Sarno, et al., T helper type 1 and 17 cells determine efficacy of interferon-beta in multiple sclerosis and experimental encephalomyelitis, Nat. Med. 16 (2010) 406–412. [29] R.C. Axtell, C. Raman, L. Steinman, Type I interferons: beneficial in Th1 and detrimental in Th17 autoimmunity, Clin. Rev. Allergy Immunol. 44 (2013) 114–120. [30] H.-P. Hartung, L. Steinman, D.S. Goodin, G. Comi, S. Cook, M. Filippi, et al., Interleukin 17F level and interferon b response in patients with multiple sclerosis, JAMA Neurol. 70 (2013) 1017–1021. [31] D. Baumjohann, K.M. Ansel, MicroRNA-mediated regulation of T helper cell differentiation and plasticity, Nat. Rev. Immunol. 13 (2013) 666–678. [32] S. Nakayamada, H. Takahashi, Y. Kanno, J.J. O’shea, Helper T cell diversity and plasticity, Curr. Opin. Immunol. 24 (2012) 297–302. [33] M. Severa, F. Rizzo, E. Giacomini, M. Salvetti, E.M. Coccia, IFN-b and multiple sclerosis: cross-talking of immune cells and integration of immunoregulatory networks, Cytokine Growth Factor Rev. 26 (2015) 229– 239. [34] J.M. Fletcher, S.J. Lalor, C.M. Sweeney, N. Tubridy, K.H.G. Mills, T cells in multiple sclerosis and experimental autoimmune encephalomyelitis, Clin. Exp. Immunol. 162 (2010) 1–11. [35] R. Deonarain, A. Verma, A.C.G. Porter, D.R. Gewert, L.C. Platanias, E.N. Fish, Critical roles for IFN- in lymphoid development, myelopoiesis, and tumor development: links to tumor necrosis factor, Proc. Natl. Acad. Sci. 100 (2003) 13453–13458. [36] N. Zietara, M. Łyszkiewicz, N. Gekara, J. Puchałka, V.A.P.M. Dos Santos, C.R. Hunt, et al., Absence of IFN-beta impairs antigen presentation capacity of splenic dendritic cells via down-regulation of heat shock protein 70, J. Immunol. 183 (2009) 1099–1109. [37] F.M. Martín-Saavedra, C. González-García, B. Bravo, S. Ballester, Beta interferon restricts the inflammatory potential of CD4+ cells through the boost of the Th2 phenotype, the inhibition of Th17 response and the prevalence of naturally occurring T regulatory cells, Mol. Immunol. 45 (2008) 4008–4019. [38] C.M. Sweeney, R. Lonergan, S.A. Basdeo, K. Kinsella, L.S. Dungan, S.C. Higgins, et al., IL-27 mediates the response to IFN-b therapy in multiple sclerosis patients by inhibiting Th17 cells, Brain Behav. Immun. 25 (2011) 1170–1181. [39] O. Stuve, S. Chabot, S.S. Jung, G. Williams, V.W. Yong, Chemokine-enhanced migration of human peripheral blood mononuclear cells is antagonized by interferon beta-1b through an effect on matrix metalloproteinase-9, J. Neuroimmunol. 80 (1997) 38–46. [40] R. a Rudick, R.M. Ransohoff, J. Lee, R. Peppler, M. Yu, P.M. Mathisen, et al., In vivo effects of interferon beta-la on immunosuppressive cytokines in multiple sclerosis, Neurology 50 (1998) 1294–1300.

53

[41] I. Teige, A. Treschow, A. Teige, R. Mattsson, V. Navikas, T. Leanderson, et al., IFN-beta gene deletion leads to augmented and chronic demyelinating experimental autoimmune encephalomyelitis, J. Immunol. 170 (2003) 4776– 4784. [42] I. Teige, Y. Liu, S. Issazadeh-Navikas, IFN-beta inhibits T cell activation capacity of central nervous system APCs, J. Immunol. 177 (2006) 3542–3553. [43] L. Börnsen, J. Romme Christensen, R. Ratzer, C. Hedegaard, H.B. Søndergaard, M. Krakauer, et al., Endogenous interferon-b-inducible gene expression and interferon-b-treatment are associated with reduced T cell responses to myelin basic protein in multiple sclerosis, PLoS One 10 (2015) e0118830. [44] P.A. Muraro, T. Leist, B. Bielekova, H.F. McFarland, VLA-4/CD49d downregulated on primed T lymphocytes during interferon-beta therapy in multiple sclerosis, J. Neuroimmunol. 111 (2000) 186–194. [45] M. Soilu-Hänninen, M. Laaksonen, A. Hänninen, J.-P. Erälinna, M. Panelius, Downregulation of VLA-4 on T cells as a marker of long term treatment response to interferon beta-1a in MS, J. Neuroimmunol. 167 (2005) 175–182. [46] R.L. Coffman, Origins of the T(H)1-T(H)2 model: a personal perspective, Nat. Immunol. 7 (2006) 539–541. [47] A.C. Murphy, S.J. Lalor, M.A. Lynch, K.H.G. Mills, Infiltration of Th1 and Th17 cells and activation of microglia in the CNS during the course of experimental autoimmune encephalomyelitis, Brain Behav. Immun. 24 (2010) 641–651. [48] K. Ota, M. Matsui, E.L. Milford, G.A. Mackin, H.L. Weiner, D.A. Hafler, T-cell recognition of an immunodominant myelin basic protein epitope in multiple sclerosis, Nature 346 (1990) 183–187. [49] S. Sakaguchi, Regulatory T cells: key controllers of immunologic selftolerance, Cell 101 (2000) 455–458. [50] M.L. Shinohara, J.-H. Kim, V.A. Garcia, H. Cantor, Engagement of the type I interferon receptor on dendritic cells inhibits T helper 17 cell development: role of intracellular osteopontin, Immunity 29 (2008) 68–78. [51] B. Guo, E.Y. Chang, G. Cheng, The type I IFN induction pathway constrains Th17-mediated autoimmune inflammation in mice, J. Clin. Invest. 118 (2008) 1680–1690. [52] M. Prinz, H. Schmidt, A. Mildner, K.-P. Knobeloch, U.-K. Hanisch, J. Raasch, et al., Distinct and nonredundant in vivo functions of IFNAR on myeloid cells limit autoimmunity in the central nervous system, Immunity 28 (2008) 675– 686. [53] N. Boivin, J. Baillargeon, P.M.I.A. Doss, A.-P. Roy, M. Rangachari, Interferon-b suppresses murine Th1 cell function in the absence of antigen-presenting cells, PLoS One 10 (2015) e0124802. [54] W. Cheng, Q. Zhao, Y. Xi, C. Li, Y. Xu, L. Wang, et al., IFN-b inhibits T cells accumulation in the central nervous system by reducing the expression and activity of chemokines in experimental autoimmune encephalomyelitis, Mol. Immunol. 64 (2015) 152–162. [55] A. Noronha, A. Toscas, M.A. Jensen, Interferon beta decreases T cell activation and interferon gamma production in multiple sclerosis, J. Neuroimmunol. 46 (1993) 145–153. [56] Y.C. Zang, J.B. Halder, A.K. Samanta, J. Hong, V.M. Rivera, J.Z. Zhang, Regulation of chemokine receptor CCR5 and production of RANTES and MIP-1alpha by interferon-beta, J. Neuroimmunol. 112 (2001) 174–180. [57] K.P. Wandinger, C.S. Stürzebecher, B. Bielekova, G. Detore, A. Rosenwald, L.M. Staudt, et al., Complex immunomodulatory effects of interferon-beta in multiple sclerosis include the upregulation of T helper 1-associated marker genes, Ann. Neurol. 50 (2001) 349–357. [58] C.L. Galligan, L.M. Pennell, T.T. Murooka, E. Baig, B. Majchrzak-Kita, R. Rahbar, et al., Interferon-beta is a key regulator of proinflammatory events in experimental autoimmune encephalomyelitis, Mult. Scler. 16 (2010) 1458– 1473. [59] L.M. Pennell, E.N. Fish, Immunoregulatory effects of interferon-b in suppression of Th17 cells, J. Interferon Cytokine Res. 34 (2014) 330–341. [60] L. Zhang, S. Yuan, G. Cheng, B. Guo, Type I IFN promotes IL-10 production from T cells to suppress Th17 cells and Th17-associated autoimmune inflammation, PLoS One 6 (2011) e28432. [61] L. Durelli, L. Conti, M. Clerico, D. Boselli, G. Contessa, P. Ripellino, et al., Thelper 17 cells expand in multiple sclerosis and are inhibited by interferonbeta, Ann. Neurol. 65 (2009) 499–509. [62] N. Kavrochorianou, M. Evangelidou, M. Markogiannaki, M. Tovey, G. Thyphronitis, S. Haralambous, IFNAR signaling directly modulates T lymphocyte activity, resulting in milder experimental autoimmune encephalomyelitis development, J. Leukoc. Biol. 99 (2016) 175–188. [63] Y. Tao, X. Zhang, M. Chopra, M.-J. Kim, K.R. Buch, D. Kong, et al., The role of endogenous IFN- in the regulation of Th17 responses in patients with relapsing-remitting multiple sclerosis, J. Immunol. 192 (2014) 5610–5617. [64] F.M. Martín-Saavedra, N. Flores, B. Dorado, C. Eguiluz, B. Bravo, A. GarcíaMerino, et al., Beta-interferon unbalances the peripheral T cell proinflammatory response in experimental autoimmune encephalomyelitis, Mol. Immunol. 44 (2007) 3597–3607. [65] V.S. Ramgolam, Y. Sha, J. Jin, X. Zhang, S. Markovic-Plese, IFN-beta inhibits human Th17 cell differentiation, J. Immunol. 183 (2009) 5418–5427. [66] M. Chen, G. Chen, H. Nie, X. Zhang, X. Niu, Y.C.Q. Zang, et al., Regulatory effects of IFN-beta on production of osteopontin and IL-17 by CD4+ T cells in MS, Eur. J. Immunol. 39 (2009) 2525–2536. [67] M. Kvarnström, J. Ydrefors, C. Ekerfelt, M. Vrethem, J. Ernerudh, Longitudinal interferon-b effects in multiple sclerosis: differential regulation of IL-10 and IL-17A while no sustained effects on IFN-b, IL-4 or IL-13, J. Neurol. Sci. 325 (2013) 79–85.

54

N. Kavrochorianou et al. / Cytokine & Growth Factor Reviews 30 (2016) 47–54

[68] J. Palace, M.I. Leite, A. Nairne, A. Vincent, Interferon beta treatment in neuromyelitis optica: increase in relapses and aquaporin 4 antibody titers, Arch. Neurol. 67 (2010) 1016–1017. [69] L. van der Fits, L.I. van der Wel, J.D. Laman, E.P. Prens, M.C.M. Verschuren, In psoriasis lesional skin the type I interferon signaling pathway is activated, whereas interferon-alpha sensitivity is unaltered, J. Invest. Dermatol. 122 (2004) 51–60. [70] A.L. Astier, D.A. Hafler, Abnormal Tr1 differentiation in multiple sclerosis, J. Neuroimmunol. 191 (2007) 70–78, doi:http://dx.doi.org/10.1016/j. jneuroim.2007.09.018. [71] M. Buc, Role of regulatory T cells in pathogenesis and biological therapy of multiple sclerosis, Mediators Inflamm. 2013 (2013) 963748. [72] M. Chen, G. Chen, S. Deng, X. Liu, G.J. Hutton, J. Hong, IFN-b induces the proliferation of CD4 + CD25 + Foxp3+ regulatory T cells through upregulation of GITRL on dendritic cells in the treatment of multiple sclerosis, J. Neuroimmunol. 242 (2012) 39–46. [73] B. Trinschek, F. Luessi, C.C. Gross, H. Wiendl, H. Jonuleit, Interferon-beta therapy of multiple sclerosis patients improves the responsiveness of T cells for immune suppression by regulatory T cells, Int. J. Mol. Sci. 16 (2015) 16330– 16346. [74] P. Praksova, P. Stourac, J. Bednarik, E. Vlckova, Z. Mikulkova, J. Michalek, Immunoregulatory T cells in multiple sclerosis and the effect of interferon beta and glatiramer acetate treatment on T cell subpopulations, J. Neurol. Sci. 319 (2012) 18–23. [75] B. Puissant-Lubrano, F. Viala, P. Winterton, M. Abbal, M. Clanet, A. Blancher, Thymic output and peripheral T lymphocyte subsets in relapsing–remitting multiple sclerosis patients treated or not by IFN-beta, J. Neuroimmunol. 193 (2008) 188–194. [76] Y. Liu, R. Carlsson, M. Comabella, J. Wang, M. Kosicki, B. Carrion, et al., FoxA1 directs the lineage and immunosuppressive properties of a novel regulatory T cell population in EAE and MS, Nat. Med. 20 (2014) 272–282. [77] A.L. Astier, G. Meiffren, S. Freeman, D.A. Hafler, Alterations in CD46-mediated Tr1 regulatory T cells in patients with multiple sclerosis, J. Clin. Invest. 116 (2006) 3252–3257. [78] A.C. Anderson, J. Reddy, R. Nazareno, R.A. Sobel, L.B. Nicholson, V.K. Kuchroo, IL-10 plays an important role in the homeostatic regulation of the autoreactive repertoire in naive mice, J. Immunol. 173 (2004) 828–834. [79] E. Bettelli, M.P. Das, E.D. Howard, H.L. Weiner, R.A. Sobel, V.K. Kuchroo, IL-10 is critical in the regulation of autoimmune encephalomyelitis as demonstrated by studies of IL-10- and IL-4-deficient and transgenic mice, J. Immunol. 161 (1998) 3299–3306. [80] D. Hesse, M. Krakauer, H. Lund, H.B. Søndergaard, S.J.W. Limborg, P.S. Sørensen, et al., Disease protection and interleukin-10 induction by endogenous interferon-b in multiple sclerosis? Eur. J. Neurol. 18 (2011) 266– 272. [81] X. Feng, D. Yau, C. Holbrook, A.T. Reder, Type I interferons inhibit interleukin10 production in activated human monocytes and stimulate IL-10 in T cells: implications for Th1-mediated diseases, J. Interferon Cytokine Res. 22 (2002) 311–319. [82] Z. Liu, C.M. Pelfrey, A. Cotleur, J.-C. Lee, R.A. Rudick, Immunomodulatory effects of interferon beta-1a in multiple sclerosis, J. Neuroimmunol. 112 (2001) 153–162. [83] M. Dominguez-Villar, C.M. Baecher-Allan, D.A. Hafler, Identification of T helper type 1-like, Foxp3+ regulatory T cells in human autoimmune disease, Nat. Med. 17 (2011) 673–675. [84] S. Abromson-Leeman, R.T. Bronson, M.E. Dorf, Encephalitogenic T cells that stably express both T-bet and ROR gamma t consistently produce IFNgamma but have a spectrum of IL-17 profiles, J. Neuroimmunol. 215 (2009) 10–24. [85] H. Kebir, I. Ifergan, J.I. Alvarez, M. Bernard, J. Poirier, N. Arbour, et al., Preferential recruitment of interferon-gamma-expressing TH17 cells in multiple sclerosis, Ann. Neurol. 66 (2009) 390–402. [86] L.J. Edwards, R.A. Robins, C.S. Constantinescu, Th17/Th1 phenotype in demyelinating disease, Cytokine 50 (2010) 19–23. [87] J. Goverman, A. Perchellet, E.S. Huseby, The role of CD8(+) T cells in multiple sclerosis and its animal models, Curr. Drug Targets. Inflamm. Allergy 4 (2005) 239–245. [88] H. Babbe, A. Roers, A. Waisman, H. Lassmann, N. Goebels, R. Hohlfeld, et al., Clonal expansions of CD8(+) T cells dominate the T cell infiltrate in active multiple sclerosis lesions as shown by micromanipulation and single cell polymerase chain reaction, J. Exp. Med. 192 (2000) 393–404. _ T. Holmøy, [89] A. Lossius, J.N. Johansen, F. Vartdal, H. Robins, B. Jurate_ Šaltyte, et al., High-throughput sequencing of TCR repertoires in multiple sclerosis reveals intrathecal enrichment of EBV-reactive CD8+ T cells, Eur. J. Immunol. 44 (2014) 3439–3452. [90] J. Killestein, M.J. Eikelenboom, T. Izeboud, N.F. Kalkers, H.J. Adèr, F. Barkhof, et al., Cytokine producing CD8+ T cells are correlated to MRI features of tissue destruction in MS, J. Neuroimmunol. 142 (2003) 141–148. [91] M. Zafranskaya, P. Oschmann, R. Engel, A. Weishaupt, J.M. van Noort, H. Jomaa, et al., Interferon-beta therapy reduces CD4+ and CD8+ T-cell reactivity in multiple sclerosis, Immunology 121 (2007) 29–39. [92] S. Paul, Shilpi, G. Lal, Role of gamma-delta (gd) T cells in autoimmunity, J. Leukoc. Biol. 97 (2015) 259–271.

[93] E. Lockhart, A.M. Green, J.L. Flynn, IL-17 production is dominated by gammadelta T cells rather than CD4T cells during Mycobacterium tuberculosis infection, J. Immunol. 177 (2006) 4662–4669. [94] L. Schirmer, V. Rothhammer, B. Hemmer, T. Korn, Enriched CD161high CCR6+ gd T cells in the cerebrospinal fluid of patients with multiple sclerosis, JAMA Neurol. 70 (2013) 345–351. [95] A. Odyniec, M. Szczepanik, M.P. Mycko, M. Stasiolek, C.S. Raine, K.W. Selmaj, Gammadelta T cells enhance the expression of experimental autoimmune encephalomyelitis by promoting antigen presentation and IL-12 production, J. Immunol. 173 (2004) 682–694. [96] Y. Kobayashi, K. Kawai, K. Ito, H. Honda, G. Sobue, Y. Yoshikai, Aggravation of murine experimental allergic encephalomyelitis by administration of T-cell receptor gammadelta-specific antibody, J. Neuroimmunol. 73 (1997) 169– 174. [97] E.D. Ponomarev, B.N. Dittel, Gamma delta T cells regulate the extent and duration of inflammation in the central nervous system by a Fas liganddependent mechanism, J. Immunol. 174 (2005) 4678–4687. [98] S.E. Blink, M.W. Caldis, G.E. Goings, C.T. Harp, B. Malissen, I. Prinz, et al., gd T cell subsets play opposing roles in regulating experimental autoimmune encephalomyelitis, Cell. Immunol. 290 (2014) 39–51. [99] N. Schmitt, Role of T follicular helper cells in multiple sclerosis, J. Nat. Sci. 1 (2015) e139. [100] M.A. Linterman, W. Pierson, S.K. Lee, A. Kallies, S. Kawamoto, T.F. Rayner, et al., Foxp3+ follicular regulatory T cells control the germinal center response, Nat. Med. 17 (2011) 975–982. [101] T. Dhaeze, E. Peelen, A. Hombrouck, L. Peeters, B. Van Wijmeersch, N. Lemkens, et al., Circulating follicular regulatory T cells are defective in multiple sclerosis, J. Immunol. 195 (2015) 832–840. Nadia Kavrochorianou obtained her BSc in biology from University of Athens in 2008 and the PhD in immunology from University of Ioannina in 2015. She joined Inflammation Research Group at Hellenic Pasteur Institute (HPI) in Athens, in 2006. During her PhD thesis, she investigated the direct effect of IFN-b on T lymphocytes in vivo, using transgenic technology techniques. From May 2010 to January 2011 she was a research scientist in the Laboratory of Viral Oncology, CNRS in Villejuif, France, where she participated in a project for the development of a cell-based assay for the quantification of the activity of TNF-a antagonists, which is available in the European market as a diagnostic assay. From 2011 to 2013 she was a study director of a Collaborative Confidential Research Project, of the Transgenic Technology Laboratory of HPI and an International Pharmaceutical Company, for optimization of biologicals, using established transgenic arthritic mouse models. Today she works at the University of Athens, ICU Research Unit, at “Agioi Anargyroi” General Hospital studying the effects of various vasotonic/inotropic drugs on the immune system of septic patients. Melina Markogiannaki received her BSc in biology from University of Ioannina in 2015. She joined the Inflammation Research Group at Hellenic Pasteur Institute, Athens, Greece, in 2011, where she performed her Bachelor thesis. She also participated in projects concerning modeling of inflammatory human diseases, such as rheumatoid arthritis and multiple sclerosis, using transgenic technology and in preclinical evaluation studies. She is currently a research scientist working on projects concerning the role of IFN-b on T cell biology during EAE.

Sylva Haralambous is Research Associate Professor, Head of Inflammation Research Group and Director of the Department of Animal Models and Transgenic Technology Laboratory, at Hellenic Pasteur Institute in Athens, Greece. In 1977 she graduated from the Biology Department of the University of Athens. During her postdoctoral studies in the Department of Immunocytochemistry at Pasteur Institute in Paris, France, she worked on natural autoimmunity. Since 1987 she works at the Hellenic Pasteur Institute. Her expertise concerns modelling human inflammatory autoimmune diseases, focusing on the modifications of adaptive immunity during TNFmediated autoimmune diseases, using transgenic technologies, as well as preclinical evaluation of biologicals. Her recent specific interest is to investigate the role of IFN-b on T cell biology and its impact on autoimmunity.