IFNbeta-1a therapy for multiple sclerosis expands regulatory CD8+ T cells and decreases memory CD8+ subset: a longitudinal 1-year study

CD8+ T cells promote HIV latency by remodeling CD4+ T cell metabolism to enhance their survival, quiescence, and stemness

HIV infection persists during antiretroviral therapy (ART) due to a reservoir of latently infected cells that harbor replication-competent virus and evade immunity. Previous ex vivo studies suggested that CD8+ T cells from people with HIV may suppress HIV expression via non-cytolytic mechanisms, but the mechanisms responsible for this effect remain unclear. Here, we used a primary cell-based in vitro latency model and demonstrated that co-culture of autologous activated CD8+ T cells with HIV-infected memory CD4+ T cells promoted specific changes in metabolic and/or signaling pathways resulting in increased CD4+ T cell survival, quiescence, and stemness. Collectively, these pathways negatively regulated HIV expression and ultimately promoted the establishment of latency. As shown previously, we observed that macrophages, but not B cells, promoted latency in CD4+ T cells. The identification of CD8-specific mechanisms of pro-latency activity may favor the development of approaches to eliminate the viral reservoir in people with HIV.

CD8+ Regulatory T Cells Induced by Lipopolysaccharide Improve Mouse Endotoxin Shock

Sepsis is a systemic inflammatory disease caused by a bacterial infection that leads to severe mortality, especially in elderly patients, because of an excessive immune response and impaired regulatory functions. Antibiotic treatment is widely accepted as the first-line therapy for sepsis; however, its excessive use has led to the emergence of multidrug-resistant bacteria in patients with sepsis. Therefore, immunotherapy may be effective in treating sepsis. Although CD8+ regulatory T cells (Tregs) are known to have immunomodulatory effects in various inflammatory diseases, their role during sepsis remains unclear. In this study, we investigated the role of CD8+ Tregs in an LPS-induced endotoxic shock model in young (8-12 wk old) and aged (18-20 mo old) mice. The adoptive transfer of CD8+ Tregs into LPS-treated young mice improved the survival rate of LPS-induced endotoxic shock. Moreover, the number of CD8+ Tregs in LPS-treated young mice increased through the induction of IL-15 produced by CD11c+ cells. In contrast, LPS-treated aged mice showed a reduced induction of CD8+ Tregs owing to the limited production of IL-15. Furthermore, CD8+ Tregs induced by treatment with the rIL-15/IL-15Rα complex prevented LPS-induced body wight loss and tissue injury in aged mice. In this study, to our knowledge, the induction of CD8+ Tregs as novel immunotherapy or adjuvant therapy for endotoxic shock might reduce the uncontrolled immune response and ultimately improve the outcomes of endotoxic shock.

Cytolytic CD4+ and CD8+ Regulatory T-Cells and Implications for Developing Immunotherapies to Combat Graft-Versus-Host Disease

Regulatory T-cells (Treg) are critical for the maintenance of immune homeostasis and tolerance induction. While the immunosuppressive mechanisms of Treg have been extensively investigated for decades, the mechanisms responsible for Treg cytotoxicity and their therapeutic potential in regulating immune responses have been incompletely explored and exploited. Conventional cytotoxic T effector cells (Teffs) are known to be important for adaptive immune responses, particularly in the settings of viral infections and cancer. CD4+ and CD8+ Treg subsets may also share similar cytotoxic properties with conventional Teffs. Cytotoxic effector Treg (cyTreg) are a heterogeneous population in the periphery that retain the capacity to suppress T-cell proliferation and activation, induce cellular apoptosis, and migrate to tissues to ensure immune homeostasis. The latter can occur through several cytolytic mechanisms, including the Granzyme/Perforin and Fas/FasL signaling pathways. This review focuses on the current knowledge and recent advances in our understanding of cyTreg and their potential application in the treatment of human disease, particularly Graft-versus-Host Disease (GVHD).

Future prospects for CD8+ regulatory T cells in immune tolerance

CD8⁺ Tregs have been long described and significant progresses have been made about their phenotype, their functional mechanisms, and their suppressive ability compared to conventional CD4⁺ Tregs. They are now at the dawn of their clinical use. In this review, we will summarize their phenotypic characteristics, their mechanisms of action, the similarities, differences and synergies between CD8⁺ and CD4⁺ Tregs, and we will discuss the biology, development and induction of CD8⁺ Tregs, their manufacturing for clinical use, considering open questions/uncertainties and future technically accessible improvements notably through genetic modifications.

The proportion of peripheral regulatory T cells in patients with Multiple Sclerosis: A meta-analysis

BACKGROUND

Accumulating evidence indicates that regulatory T cells (Tregs) play an important role in the maintenance of immune tolerance. And dysfunction or deficiency of Tregs is thought to be involved in the pathogenesis of Multiple Sclerosis (MS). Nevertheless, previous studies reporting Tregs in patients were controversial due to the different markers adopted to identify Tregs. To clarify the status of Tregs in the pathogenesis of MS patients, we did a meta-analysis of the results published previously to assess the proportion of Tregs in peripheral blood (PB) in patients with MS.

METHODS

We systematically searched Embase, PubMed, Cochrane, Web of Knowledge, FDA.gov, and Clinical Trials.gov for the studies reporting the proportion of Tregs in MS patients. Our main endpoints were the proportion of Tregs among CD4⁺ T cells in PB defined by different markers. We assessed pooled data by using a random-effects model. Our meta-analysis had been registered at International Prospective Register of Systematic Reviews (PROSPERO) (number CRD42017064906).

RESULTS

Of 885 identified studies, a total 16 studies were selected in our analysis. There was no significant difference between MS patients and control subjects in Tregs identified by all Tregs definition methods [-0.07, (-0.46, 0.31, p = 0.706)] and Tregs defined by "CD4⁺ CD25⁺" [0.24, (-0.18, 0.65), p = 0.263]. Compared with control subjects, MS patients had a lower proportion of Tregs defined by "CD4⁺ CD25⁺ FOXP3⁺" [-0.75, (-0.46,0.31), p = 0.001].

CONCLUSION

Under random effect model of meta-analysis, the data showed that the results of Tregs in MS were different according to the definition method; and the proportion of Tregs defined by "CD4⁺ CD25⁺ FOXP3⁺" was decreased in MS. That result demonstrates that FOXP3 may be a vital definition of Tregs, and Tregs defined by stricter definition methods should be involved in the pathogenic mechanisms of MS.

Description of CD8+ Regulatory T Lymphocytes and Their Specific Intervention in Graft-versus-Host and Infectious Diseases, Autoimmunity, and Cancer

Gershon and Kondo described CD8⁺ Treg lymphocytes as the first ones with regulating activity due to their tolerance ability to foreign antigens and their capacity to inhibit the proliferation of other lymphocytes. Regardless, CD8⁺ Treg lymphocytes have not been fully described-unlike CD4⁺ Treg lymphocytes-because of their low numbers in blood and the lack of specific and accurate population markers. Still, these lymphocytes have been studied for the past 30 years, even after finding difficulties during investigations. As a result, studies have identified markers that define their subpopulations. This review is focused on the expression of cell membrane markers as CD25, CD122, CD103, CTLA-4, CD39, CD73, LAG-3, and FasL as well as soluble molecules such as FoxP3, IFN-γ, IL-10, TGF-β, IL-34, and IL-35, in addition to the lack of expression of cell activation markers such as CD28, CD127 CD45RC, and CD49d. This work also underlines the importance of identifying some of these markers in infections with several pathogens, autoimmunity, cancer, and graft-versus-host disease as a strategy in their prevention, monitoring, and cure.

IFN-β Facilitates Neuroantigen-Dependent Induction of CD25+ FOXP3+ Regulatory T Cells That Suppress Experimental Autoimmune Encephalomyelitis

This study introduces a flexible format for tolerogenic vaccination that incorporates IFN-β and neuroantigen (NAg) in the Alum adjuvant. Tolerogenic vaccination required all three components, IFN-β, NAg, and Alum, for inhibition of experimental autoimmune encephalomyelitis (EAE) and induction of tolerance. Vaccination with IFN-β + NAg in Alum ameliorated NAg-specific sensitization and inhibited EAE in C57BL/6 mice in pretreatment and therapeutic regimens. Tolerance induction was specific for the tolerogenic vaccine Ag PLP178-191 or myelin oligodendrocyte glycoprotein (MOG)35-55 in proteolipid protein- and MOG-induced models of EAE, respectively, and was abrogated by pretreatment with a depleting anti-CD25 mAb. IFN-β/Alum-based vaccination exhibited hallmarks of infectious tolerance, because IFN-β + OVA in Alum-specific vaccination inhibited EAE elicited by OVA + MOG in CFA but not EAE elicited by MOG in CFA. IFN-β + NAg in Alum vaccination elicited elevated numbers and percentages of FOXP3+ T cells in blood and secondary lymphoid organs in 2D2 MOG-specific transgenic mice, and repeated boosters facilitated generation of activated CD44high CD25+ regulatory T cell (Treg) populations. IFN-β and MOG35-55 elicited suppressive FOXP3+ Tregs in vitro in the absence of Alum via a mechanism that was neutralized by anti-TGF-β and that resulted in the induction of an effector CD69+ CTLA-4+ IFNAR+ FOXP3+ Treg subset. In vitro IFN-β + MOG-induced Tregs inhibited EAE when transferred into actively challenged recipients. Unlike IFN-β + NAg in Alum vaccines, vaccination with TGF-β + MOG35-55 in Alum did not increase Treg percentages in vivo. Overall, this study indicates that IFN-β + NAg in Alum vaccination elicits NAg-specific, suppressive CD25+ Tregs that inhibit CNS autoimmune disease. Thus, IFN-β has the activity spectrum that drives selective responses of suppressive FOXP3+ Tregs.

Regulatory Cell Populations in Relapsing-Remitting Multiple Sclerosis (RRMS) Patients: Effect of Disease Activity and Treatment Regimens

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system (CNS) of autoimmune etiology that results from an imbalance between CNS-specific T effector cells and peripheral suppressive mechanisms mediated by regulatory cells (RC). In this research, we collected blood samples from 83 relapsing remitting MS (RRMS) patients and 45 healthy persons (HC), to assess the sizes of their RC populations, including CD4⁺CD25(high)Foxp3⁺ (nTregs), CD3⁺CD4⁺HLA(-)G⁺, CD3⁺CD8⁺CD28(-), CD3⁺CD56⁺, and CD56(bright) cells, and how RC are affected by disease activity (acute phase or remission) and types of treatment (methylprednisolone, interferon, or natalizumab). In addition, we isolated peripheral blood mononuclear cells (PBMC) and cultured them with peptides mapping to myelin antigens, to determine RC responsiveness to autoantigens. The results showed decreased levels of nTregs in patients in the acute phase ± methylprednisolone and in remission + natalizumab, but HC levels in patients in remission or receiving interferon. Patients + interferon had the highest levels of CD3⁺CD4⁺HLA(-)G⁺ and CD3⁺CD8⁺CD28(-) RC, and patients in the acute phase + methylprednisolone the lowest. Patients in remission had the highest levels of CD3⁺CD56⁺, and patients in remission + natalizumab the highest levels of CD56(bright) cells. Only nTregs responded to autoantigens in culture, regardless of disease activity or treatment. The highest suppressive activity was exhibited by nTregs from patients in remission. In conclusion, in RRMS disease activity and type of treatment affect different RC populations. nTregs respond to myelin antigens, indicating that it is possible to restore immunological tolerance through nTreg induction.

Multiparametric flow cytometric analysis of whole blood reveals changes in minor lymphocyte subpopulations of multiple sclerosis patients

OBJECTIVE

The objective of this study is to characterise the functionally relevant minor lymphocyte subpopulations in whole blood of multiple sclerosis (MS) patients and their potential utility as biomarkers for treatment follow up.

MATERIAL AND METHODS

Peripheral blood from 40 healthy donors (HD) and 66 MS patients [23 relapsing-remitting (RRMS) without treatment, 27 RRMS undergoing treatment (16 IFN-β, 11 natalizumab), and 16 progressive forms (eight secondary progressive and eight primary progressive)] was analysed by multiparametric flow cytometry.

RESULTS

Untreated MS patients showed a decrease in early effector memory (CD45RA(-)CCR7(-)CD27(+)) CD4(+) and CD8(+) T cells and an increase in Th17 lymphocytes in peripheral blood compared with HD. Regarding the effect of treatment, whereas no differences in relative percentages of cellular subpopulations were observed in patients under IFN-β treatment, those under treatment with natalizumab had an increased percentage of early effector memory CD4(+) (CD45RA(-)CCR7(-)CD27(+)), central memory CD8(+) (CD45RA(-)CCR7(+)CD27(+)) T cells, recent thymic emigrants (CD4(+) CD45RA(+)CCR7(+)CD27(+)CD31(+)PTK7(+)) and transitional B cells (CD19(+)CD27(-)CD24(hi)CD38(hi)).

CONCLUSIONS

Multiparametric flow cytometry analysis of whole blood is a robust, reproducible, and sensitive technology to monitor the effect of MS treatments even in minor lymphocyte subpopulations that might represent useful biomarkers of treatment response.

The low EOMES/TBX21 molecular phenotype in multiple sclerosis reflects CD56+ cell dysregulation and is affected by immunomodulatory therapies

Multiple Sclerosis (MS) is an autoimmune disease treated by therapies targeting peripheral blood cells. We previously identified that expression of two MS-risk genes, the transcription factors EOMES and TBX21 (ET), was low in blood from MS and stable over time. Here we replicated the low ET expression in a new MS cohort (p<0.0007 for EOMES, p<0.028 for TBX21) and demonstrate longitudinal stability (p<10(-4)) and high heritability (h(2)=0.48 for EOMES) for this molecular phenotype. Genes whose expression correlated with ET, especially those controlling cell migration, further defined the phenotype. CD56+ cells and other subsets expressed lower levels of Eomes or T-bet protein and/or were under-represented in MS. EOMES and TBX21 risk SNP genotypes, and serum EBNA-1 titres were not correlated with ET expression, but HLA-DRB1*1501 genotype was. ET expression was normalised to healthy control levels with natalizumab, and was highly variable for glatiramer acetate, fingolimod, interferon-beta, dimethyl fumarate.

CD8(+) T-Cells as Immune Regulators of Multiple Sclerosis

The vast majority of studies regarding the immune basis of MS (and its animal model, EAE) have largely focused on CD4(+) T-cells as mediators and regulators of disease. Interestingly, CD8(+) T-cells represent the predominant T-cell population in human MS lesions and are oligoclonally expanded at the site of pathology. However, their role in the autoimmune pathologic process has been both understudied and controversial. Several animal models and MS patient studies support a pathogenic role for CNS-specific CD8(+) T-cells, whereas we and others have demonstrated a regulatory role for these cells in disease. In this review, we describe studies that have investigated the role of CD8(+) T-cells in MS and EAE, presenting evidence for both pathogenic and regulatory functions. In our studies, we have shown that cytotoxic/suppressor CD8(+) T-cells are CNS antigen-specific, MHC class I-restricted, IFNγ- and perforin-dependent, and are able to inhibit disease. The clinical relevance for CD8(+) T-cell suppressive function is best described by a lack of their function during MS relapse, and importantly, restoration of their suppressive function during quiescence. Furthermore, CD8(+) T-cells with immunosuppressive functions can be therapeutically induced in MS patients by glatiramer acetate (GA) treatment. Unlike CNS-specific CD8(+) T-cells, these immunosuppressive GA-induced CD8(+) T-cells appear to be HLA-E restricted. These studies have provided greater fundamental insight into the role of autoreactive as well as therapeutically induced CD8(+) T-cells in disease amelioration. The clinical implications for these findings are immense and we propose that this natural process can be harnessed toward the development of an effective immunotherapeutic strategy.

Changes in B and T-cell subsets and NMO-IgG levels after immunoglobulins and rituximab treatment for an acute attack of neuromyelitis optica

BACKGROUND

There is increasing evidence supporting that neuromyelitis optica (NMO) is an inflammatory humoral mediated disorder associated with NMO-IgG/AQP-4 antibodies. However, little is known about the subsets of B cells and T cells that contribute to the pathogenesis or therapy response.

OBJECTIVES

To describe the clinical and immunological changes associated with intravenous immunoglobulins (IV-Igs) plus rituximab (RTX) in a patient with a severe acute attack of NMO and intrathecal synthesis of NMO-IgG/AQP-4, who previously did not respond to intravenous methylprednisolone and plasma exchange.

METHODS

We sequentially analysed the levels of NMO-IgG/AQP-4 by immunohistochemistry, and B and T cells subsets by multiparametric flow-cytometry, in the CSF and peripheral blood (PB), before and alter IV-Igs plus RTX therapy.

RESULTS

In the CSF before treatment, and compared with PB, there was a higher percentage of CD4(+) T cells and a lower percentage of CD8(+) T cells and CD19(+) B cells. After therapy, the percentage of CD4(+) T cells remained high, and that of CD8(+) T cells increased. The observed decrease in the percentage of CD19(+) B cells was lower than in the PB. When the CSF was compared, it was found that the percentage of effector-memory and effector CD8(+) T cells had increased after therapy, and that of IgM memory B cells and switched-memory B cells decreased. The observed changes paralleled the decrease of NMO-IgG/AQP-4 results to negative and the clinical improvement.

CONCLUSIONS

Our findings confirm that, besides intrathecal humoral immune response against AQP4, B and T cell subsets are involved in the modulation of inflammation within and outside the central nervous system.

Low DPP4 expression and activity in multiple sclerosis

Multiple sclerosis (MS) is a prototypic Th1/Th17 chronic autoimmune disease of the central nervous system. Dipeptidyl peptidase 4 (DPP4 or CD26) is a multifunctional molecule involved in autoimmune diseases' pathophysiology. We sought to integrate disparate pieces of data and analyze the plasma levels of sDPP4, DPP activity and DPP4 surface expression on T-cells in 129 MS patients with different clinical forms and 53 healthy controls, across two independent cohorts. Herein, we provide new evidence that sDPP4 concentration and DPP activity are significantly lower in MS patients than controls (p < 0.0001 and p < 0.01, respectively). In contrast, the frequency of circulating CD8(+)DPP4(hi) T-cells (p = 0.02) was increased in MS patients. This is the first study that simultaneously analyzes DPP4 expression and function in a large cohort of MS patients. Our data indicate a putative role for DPP4 in MS pathophysiology and suggest that a deeper understanding of surface versus shed DPP4 biology is warranted.

Cross talk between cancer and immune cells: exploring complex dynamics in a microfluidic environment

The reconstitution of a complex microenvironment on microfluidic chips is one of the cornerstones to demonstrate the improved flexibility of these devices with respect to macroscale in vitro approaches. In this work, we realised an on-chip model to investigate the interactions between cancer and immune system. To this end, we exploited mice deficient (Knock Out, KO) for interferon regulatory factor 8 (IRF-8), a transcription factor essential for the induction of competent immune responses, to investigate how IRF-8 gene expression contributes to regulate immune and melanoma cells crosstalk. In vivo, IRF-8 KO mice are highly permissive to B16 melanoma growth due to failure of immune cells to properly exert immunosurveillance. B16 cells and immune cells isolated from the spleen of wild type (WT) and IRF-8 KO mice were co-cultured for one week in a PDMS platform and monitored by fluorescence microscopy and time-lapse recordings. We observed that WT spleen cells migrated through microchannels connecting the culturing chambers towards B16 cells and tightly interacted with tumor cells, forming clusters of activation. In contrast, IRF-8 KO immune cells poorly interacted with melanoma cells. In parallel, B16 cells were more attracted towards microchannels, acquiring a more invasive behaviour in the presence of IRF-8 KO spleen cells, with respect to WT cells. Our results strongly confirm the in vivo observations and highlight the value of on-chip co-culture systems as a useful in vitro tool to elucidate the reciprocal interactions between cancer cells and host immune system, with relevant impact in the development of more effective anti-tumor therapeutic strategies.

Perforin expression by CD4+ regulatory T cells increases at multiple sclerosis relapse: sex differences

Multiple sclerosis (MS) represents the leading cause of neurological deficit among young adults, affecting women more frequently than men. In MS, the extent of central nervous system lesions is determined by the net balance between self-reactive and regulatory T-cells at any given time, among other factors, as well as by the effect of inflammatory response. Here, we studied both CD4+ and CD8+ T_Reg in parallel in blood and CSF during MS relapse. A recruitment of both regulatory CD4+ and CD8+ T cells (T_Reg) within the cerebrospinal fluid (CSF) takes place during MS relapse. Not previously described, the presence of CD4+ T_Reg in CSF was higher in women than in men, which could account for the sexual dimorphism in the incidence of MS. A direct correlation between plasma oestradiol (E2) and IL-2 levels was observed, in line with a putative circuit of E2 and perforin expression by CD4+ T_Reg playing a role in MS. Also, serum IFN-alpha was higher in females, with direct correlation with serum E2 levels. This is the first study to analyze perforin expression by CD4+ T_Reg in MS, which was greatly enhanced in CSF, what points out a relevant role of this molecule in the suppressive effects of the CD4+ T_Reg in MS, and contributes to the understanding of MS pathophysiology.

Two discreet subsets of CD8 T cells modulate PLP(91-110) induced experimental autoimmune encephalomyelitis in HLA-DR3 transgenic mice

Previously we showed that transgenic mice expressing human HLA-DR3 gene are susceptible to PLP(91-110) induced experimental autoimmune encephalomyelitis (EAE) and can serve as an animal model of multiple sclerosis (MS). HLA-DR3 mice with EAE showed increased number of CD8 T cells indicating their important role in disease pathogenesis. The role of CD8 T cells in MS, an inflammatory demyelinating disease of CNS, has been enigmatic as it has been assigned both regulatory and pathogenic roles. Therefore, to evaluate the role of CD8 T cells, we generated CD8 deficient HLA-DR3 transgenic mice (DR3.CD8(-/-)). Immunization with PLP(91-110) led to more severe EAE in DR3.CD8(-/-) mice compared to HLA-DR3 mice indicating a regulatory role for CD8 T cells. Interestingly, DR3.CD8(-/-) mice with EAE showed decreased CNS pathology compared to DR3 mice thus suggesting a pathogenic role for CD8 T cells. We show that these two subsets of CD8 T cells can be differentiated based on the surface expression of CD122 (IL-2 Rβ chain). CD8 T cells expressing CD122 (CD8+CD122+) play a regulatory role while CD8+CD122- T cells act as a pathogenic subset. CD122 expressing CD8 T cells are the regulatory subset of CD8 T cells and regulate the encephalitogenic CD4 T cells through direct modulation of antigen presenting cells and/or through the release of immunoregulatory cytokines such as IL-10, IFNγ and TGFβ. We also showed that adoptive transfer of CD8CD122- T cells caused increased spinal cord demyelination indicating that these are pathogenic subset of CD8 T cells. Our study suggests that CD8+ T cells play both regulatory as well as pathogenic role in disease pathogenesis of EAE. A better understanding of these subsets could aid in designing novel therapy for MS patients.