Transforming growth factor-β micro-environment mediated immune cell functions in cervical cancer

Propensity to develop cervical cancer (CC) in human papilloma virus (HPV) infected individual could potentially involve the impaired immune functioning. Several stages of HPV surveillance by immune cells in tumor micro-environment (TME) is regulated mainly by transforming growth factor-beta (TGF-β) and is crucial for the establishment of CC. The role of TGF-β in the initiation and progression of CC is very complex and involve different suppressor of mothers against decapentaplegic homolog (SMAD) dependent and SMAD independent signaling mechanism(s). This review summarizes the handling of HPV by immune cells such as T lymphocytes, B lymphocytes, natural killer cells (NK), dendritic cells (DC), monocytes, macrophages, myeloid derived suppressor cells (MDSC) and their regulation by TGF-β. The hijack mechanisms adapted by HPV to evade this surveillance process is discussed. Biomarkers indicating the stages of CC and immune checkpoints that can be targeted for improved outcome are included for immune-based theragnostics. This review also addresses the direct actions of TGF-β on CC cells and tumor/immune cell interactions. Therapies focused on targeting TGF-β using small molecule inhibitors, monoclonal antibodies and TGF-β chimeric antigen receptor (CAR)T cells are collated to understand the current strategies related to TGF-β in the management of CC.

Serum cytokines profile changes in amyotrophic lateral sclerosis

Background

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder, characterized by progressive limb weakness, dysphagia, dysphonia, and respiratory failure due to degeneration of upper and lower motor neurons. The pathogenesis of ALS is still unclear. Neuroinflammation has been found to be involved in its development and progression. Cytokines play a significant role in the inflammatory process. This study aims to identify novel biomarkers that may assist in the diagnosis of ALS.

Methods

In Fujian Medical University Union Hospital and Huashan Hospital Fudan University, two independent centers, we prospectively recruited 50 ALS patients, and 41 healthy controls (25 ALS and 26 controls in the first stage and 25 ALS and 15 controls in the validation stage). An 18-plex Luminex kit was used to screen the serum cytokines levels in the first stage. Commercial ELISA kits were used to measure the levels of target cytokines in the validation stage. A single-molecule array HD-X platform was applied to assess the levels of serum neurofilament light chain (NFL).

Results

The levels of serum IL-18 were markedly increased in patients with ALS in the first stage (p = 0.016). The ROC curve showed an area under the curve at 0.695 (95% CI 0.50-0.84) in distinguishing ALS patients from healthy controls. The IL-21 was decreased in elderly patients when grouped by 55 years old (the medium age). Furthermore, the IL-5, IL-13, IL-18, and NFL had a positive relationship with the disease progression of ALS. We also found that serum IL-18 was markedly increased in ALS patients in the validation stage (167.67 [148.25-175.59] vs 116.44 [102.43-122.19]pg/ml, p < 0.0015).

Conclusion

In this study, we identified systemic cytokine profile changes in the serum of ALS patients, especially the elevated IL-18, as well as the decreased IL-21 in elder patients. These changes in serum cytokine profiles may shed new light on an in-depth understanding of the immunopathogenic characteristics of ALS.

Assessing the Causal Relationship between Genetically Determined Inflammatory Cytokines and Parkinson's Disease Risk: A Bidirectional Two-Sample Mendelian Randomization Study

Background

Observational studies have suggested an association between inflammatory cytokines and Parkinson's disease (PD). This Mendelian randomization (MR) was conducted to further assess the causal correlations between inflammatory cytokines and PD.

Methods

Genetic instruments associated with inflammatory cytokines were extracted from a large summary genome-wide association studies (GWAS) involving 8,293 European participants. Summary-level statistics for PD were obtained from a large-sample GWAS containing 17 studies that involved European participants. Causalities of exposures and outcomes were explored mainly using inverse variance weighted (IVW) method.

Results

The IVW method indicated that basic fibroblast growth factor (FGFBasic), interleukin-2 (IL-2), and macrophage migration inhibitory factor (MIF) may be suggestively associated with the risk of PD (OR: 0.71, 95%CI: 0.52-0.96, P = 0.027; OR: 1.18, 95%CI: 1.01-1.38, P = 0.041; and OR: 1.23, 95%CI: 1.04-1.46, P = 0.018). In the reverse direction, monokine induced by interferon gamma (MIG), beta nerve growth factor (bNGF), interleukin-17 (IL-17), and interferon gamma (IFNg) are suggested to be the consequences of PD.

Conclusion

Our MR analysis indicated that suggestive associations between circulating levels of FGFBasic, IL-2, and MIF and PD risk. In addition, MIG, bNGF, IL-17, and IFNg are more likely to be involved in the development of downstream PD.

Plant-derived galactolipids enhance specific antibody production and induce class-switch as vaccine adjuvant

Various plant-derived compounds can activate immune responses against bacterial infections, and this property contributes to them being developed as effective and safe adjuvants for vaccines. This study evaluated the potential adjuvant effects of a galactolipid-enriched fraction generated from the medicinal plant Crassocephalum rabens (designated CRA). Heat shock protein 60 of periodontal disease pathogen Actinobacillus actinomycetemcomitans (AaHSP60) was taken as an antigen and mixed with CRA. The AaHSP60/CRA mixture was then injected intraperitoneally into the BALB/c mice. Titers and affinity of specific antibodies were measured by ELISA. Cytokine profiles in mouse serum or culture media of AaHSP60/CRA-treated splenocytes were analyzed by cytokine multiplex assay and ELISA kits. B cell differentiation and macrophage activation were determined by phenotyping. CRA dramatically enhanced specific antibody titers and induced Ig class switch, as shown by increases in the IgG2a, IgG2b, and IgG3 proportions of total Ig in mouse serum. Furthermore, CRA-induced anti-AaHSP60 antibodies had cross-reactivity to other bacterial HSP60s. Cell-based and animal results demonstrated that CRA induced the release of IL-21 and B cell activating factor (BAFF), which stimulated B cell differentiation. CRA enhanced cell proliferation, uptake ability, and antigen presentation in mouse phagocytes. CRA served as a vaccine adjuvant that enhance mouse immunity against pathogenic antigens. CRA strengthened the activation and capabilities of phagocytes and B cells. Therefore, CRA may be a promising adjuvant for bacterial vaccines including periodontal disease.

An Intestinal Th17 Subset is Associated with Inflammation in Crohn's Disease and Activated by Adherent-invasive Escherichia coli

IFNγ-producing ex-Th17 cells ['Th1/17'] were shown to play a key pathogenic role in experimental colitis and are abundant in the intestine. Here, we identified and characterised a novel, potentially colitogenic subset of Th17 cells in the intestine of patients with Crohn's disease [CD]. Human Th17 cells expressing CCR5 ['pTh17'] co-expressed T-bet and RORC/γt and produced very high levels of IL-17, together with IFN-γ. They had a gene signature of Th17 effector cells and were distinct from established Th1/17 cells. pTh17 cells, but not Th1/17 cells, were associated with intestinal inflammation in CD, and decreased upon successful anti-TNF therapy with infliximab. Conventional CCR5[-]Th17 cells differentiated to pTh17 cells with IL-23 in vitro. Moreover, anti-IL-23 therapy with risankizumab strongly reduced pTh17 cells in the intestine. Importantly, intestinal pTh17 cells were selectively activated by adherent-invasive Escherichia coli [AIEC], but not by a commensal/probiotic E. coli strain. AIEC induced high levels of IL-23 and RANTES from dendritic cells [DC]. Intestinal CCR5+Th1/17 cells responded instead to cytomegalovirus and were reduced in ulcerative colitis [UC], suggesting an unexpected protective role. In conclusion, we identified an IL-23-inducible subset of human intestinal Th17 cells. pTh17 cells produced high levels of pro-inflammatory cytokines, were selectively associated with intestinal inflammation in CD, and responded to CD-associated AIEC, suggesting a key colitogenic role.

AIRE-overexpressing BMDCs suppress TFH cells through ICOSL to prevent and attenuate autoimmune diabetes in NOD mice

The strong genetic association between autoimmune regulator (AIRE) and autoimmune diseases indicates its critical role in immune tolerance. AIRE deficiency is thought to promote the development of follicular helper T (TFH) cells, which are considered to be essential in B cell proliferation. Excessive TFH cell generation is a key step towards the development of autoimmune diseases, including type 1 diabetes. However, the potential mechanism by which AIRE contributes to the generation and function of the TFH cell population has remained elusive. We show that AIRE reduced TFH cell generation by inhibiting the expression of inducible costimulatory ligand (ICOSL), interleukin (IL)-6 and IL-27 in dendritic cells (DCs). To understand the precise impact of AIRE-overexpressing bone marrow-derived DCs (AIRE-BMDCs) on type 1 diabetes progression and the associated molecular mechanisms, we transferred AIRE-BMDCs to recipient NOD mice and found that transplantation of AIRE-BMDCs can prevent or delay the onset of diabetes, attenuate diabetes after the establishment of overt hyperglycaemia, and lead to the inhibition of autoreactive pathological TFH cells and germinal centre (GC) B cells. To further determine the potential mechanism underlying this TFH cell depletion, BMDCs were cotransferred with recombinant mouse ICOSL (ICOSLG protein). We demonstrated that NOD mice were more susceptible to diabetes when they received AIRE-BMDCs and ICOSLG than when they received only mock-vehicle BMDCs (GFP-BMDCs). In addition, we did not observe the reversal of diabetes in any mice subjected to this cotransfer system. A single cycle of ICOSLG treatment temporarily promoted TFH cell proliferation and GC development. Our results reveal a mechanistic role of AIRE-BMDCs in the initiation of TFH cell differentiation, and the AIRE-mediated decrease in ICOSL expression in BMDCs plays a critical role. The effect of decreased ICOSL expression in type 1 diabetes will guide the design and evaluation of parallel studies in patients.

High-dimensional analysis defines multicytokine T-cell subsets and supports a role for IL-21 in atopic dermatitis

BACKGROUND

Flow cytometry is a well-accepted approach for immune profiling; however, its value is restricted by the limited number of markers that can be analyzed simultaneously. Mass cytometry/CyTOF offers broad-scale immune characterization integrating large number of parameters. While partial blood phenotyping was reported in atopic dermatitis (AD), patients' comprehensive profiling, critical for leveraging new targeted treatments, is not available. IL-21 may be involved in inflammatory skin diseases but its role in AD is not well established.

METHODS

We studied T-cell polarization in the blood of 20 moderate-to-severe AD and 15 controls. Using CyTOF and an unsupervised analysis, we measured the frequencies and mean metal intensities of activated polar CD4⁺ /CD8⁺ T-cell subsets. Immunohistochemistry, immunofluorescence, and qRT-PCR were used to analyze skin samples.

RESULTS

Examining 24 surface, intracellular markers, and transcription factors, we identified six CD4⁺ and five CD8⁺ T-cell metaclusters. A CD4⁺ skin-homing IL-13⁺ monocytokine and a novel IL-13⁺ IL-21⁺ multicytokine metaclusters were increased in AD vs. controls (p < .01). While IL-13 signature characterized both clusters, levels were significantly higher in the IL-21⁺ group. Both clusters correlated with AD severity (r = 0.49, p = .029). Manual gating corroborated these results and identified additional multicytokine subsets in AD. Immunohistochemistry and immunofluorescence, validated by mRNA expression, displayed significantly increasedIL-21 counts and colocalization with IL-13/IL-4R in AD skin.

CONCLUSION

A multicytokine signature characterizes moderate-to-severe AD, possibly explaining partial therapeutic responses to one cytokine targeting, particularly in severe patients. Prominent IL-21 signature in blood and skin hints for a potential pathogenic role of IL-21 in AD.

Association of interleukin-2, interleukin-21 and interleukin-23 with hyperlipidemia in pediatric type 1 diabetes

BACKGROUND

In type 1 diabetes mellitus (T1DM), cytokines have a central role in orchestrating multicellular relations between β-cells and immune cells. This study aims to investigate the role of interleukin (IL)-21, IL-23, and IL-2, and their association with dyslipidemia in T1DM children.

METHODS

The sample population consisted of 30 healthy controls and 70 children with T1DM, the latter of which were split into two groups according to the duration of their T1DM diagnosis: recent (≤ 1 year; n = 21) and older (> 1 year; n = 49) diagnoses.

RESULTS

Fasting blood sugar and glycated hemoglobin levels in all diabetic children were significantly (P < 0.001) higher, whereas levels of plasma C-peptide were markedly (P < 0.001) lower in children with T1DM compared to healthy controls. In older T1DM diagnosis children, the levels of creatinine were noticeably (P < 0.05) increased relative to healthy controls. In all diabetic children, levels of total triglyceride, cholesterol, and low-density lipoprotein were increased significantly (P < 0.001) than those of healthy controls. Furthermore, the IL-21 and IL-23 mRNA expressions of all children with T1DM were elevated significantly (P < 0.001) relative to healthy controls, whereas IL-2 levels revealed a significant (P < 0.001) decrease in all diabetic children.

CONCLUSION

There was a synergistic interplay between IL-21 and IL-23 with an antagonistic action of IL-2 in T1DM patients, and all three interleukins were associated with dyslipidemia in diabetic children. Importantly, therapies targeting IL-21 and IL-23 are promising targets for preventive strategies against the development of T1DM and its complications.

IL-21/IL-21R Signaling Aggravated Respiratory Inflammation Induced by Intracellular Bacteria through Regulation of CD4+ T Cell Subset Responses

The IL-21/IL-21R interaction plays an important role in a variety of immune diseases; however, the roles and mechanisms in intracellular bacterial infection are not fully understood. In this study, we explored the effect of IL-21/IL-21R on chlamydial respiratory tract infection using a chlamydial respiratory infection model. The results showed that the mRNA expression of IL-21 and IL-21R was increased in Chlamydia muridarum-infected mice, which suggested that IL-21 and IL-21R were involved in host defense against C. muridarum lung infection. IL-21R^-/- mice exhibited less body weight loss, a lower bacterial burden, and milder pathological changes in the lungs than wild-type (WT) mice during C. muridarum lung infection. The absolute number and activity of CD4⁺ T cells and the strength of Th1/Th17 responses in IL-21R^-/- mice were significantly higher than those in WT mice after C. muridarum lung infection, but the Th2 response was weaker. Consistently, IL-21R^-/- mice showed higher mRNA expression of Th1 transcription factors (T-bet/STAT4), IL-12p40, a Th17 transcription factor (STAT3), and IL-23. The mRNA expression of Th2 transcription factors (GATA3/STAT6), IL-4, IL-10, and TGF-β in IL-21R^-/- mice was significantly lower than that in WT mice. Furthermore, the administration of recombinant mouse IL-21 aggravated chlamydial lung infection in C57BL/6 mice and reduced Th1 and Th17 responses following C. muridarum lung infection. These findings demonstrate that IL-21/IL-21R may aggravate chlamydial lung infection by inhibiting Th1 and Th17 responses.

The inflammation in cutaneous lichen planus is dominated by IFN-ϒ and IL-21-A basis for therapeutic JAK1 inhibition

Cutaneous lichen planus (CLP) and psoriasis (PSO) are both common chronic inflammatory skin diseases for which development of new treatments requires the identification of key targets. While PSO is a typical Th17/IL-17-disorder, there is some evidence that Th1/IFN-ɣ dominate the inflammatory process in CLP. Nonetheless, the immunopathogenesis of CLP is not fully explained and key immunological factors still have to be recognized. In this study, we compared the immune signature of CLP lesions with the well-characterized inflammation present in PSO skin. First, we analysed the histological and immunohistological characteristics of CLP and PSO. Second, we assessed the cytokine expression (IL1A, IL1B, IL4, IL6, IL8, IL10, IL17A, IL19, IL21, IL22, IL23A, IL13, IFNG, TNF, IL12A, IL12B and IL36G) of lesional skin of CLP with PSO by qPCR. Histology revealed a similar epidermal thickness in CLP and PSO. Immunohistochemically, both diseases presented with an inflammatory infiltrate mainly composed by CD3⁺ CD4⁺ T cells rather than CD3⁺ CD8⁺ . Importantly, mRNA analysis showed a distinct cytokine signature: while levels of IL12B, IL1A, IL6 and IL23 were similar between the two groups, the characteristic PSO-associated cytokines IL8, IL17A, IL22, IL19 and IL36G were expressed at very low levels in CLP. In contrast, CLP lesional skin was dominated by the expression of IFNG, IL21, IL4, IL12A and TNF. Immunohistochemistry confirmed the dominance of IL-21, IFN-ɣ and also pSTAT1 in the dermal infiltrate of CLP, while IL-17A was more present in PSO. Collectively, this study improves our understanding of the immunological factors dominating CLP. The dominating cytokines and signalling proteins identified suggest that anti-cytokine therapeutics like JAK inhibitors may be beneficial in CLP.

Identification of a super-functional Tfh-like subpopulation in murine lupus by pattern perception

Dysregulated cytokine expression by T cells plays a pivotal role in the pathogenesis of autoimmune diseases. However, the identification of the corresponding pathogenic subpopulations is a challenge, since a distinction between physiological variation and a new quality in the expression of protein markers requires combinatorial evaluation. Here, we were able to identify a super-functional follicular helper T cell (Tfh)-like subpopulation in lupus-prone NZBxW mice with our binning approach "pattern recognition of immune cells (PRI)". PRI uncovered a subpopulation of IL-21⁺ IFN-γ^high PD-1^low CD40L^high CXCR5^- Bcl-6^- T cells specifically expanded in diseased mice. In addition, these cells express high levels of TNF-α and IL-2, and provide B cell help for IgG production in an IL-21 and CD40L dependent manner. This super-functional T cell subset might be a superior driver of autoimmune processes due to a polyfunctional and high cytokine expression combined with Tfh-like properties.

CD4+ T Cells of Myasthenia Gravis Patients Are Characterized by Increased IL-21, IL-4, and IL-17A Productions and Higher Presence of PD-1 and ICOS

Myasthenia gravis (MG) is an autoimmune disease mediated by autoantibodies predominantly against the acetylcholine receptor (AChR). Specific T cell subsets are required for long-term antibody responses, and cytokines secreted mainly from CD4⁺ T cells regulate B cell antibody production. The aim of this study was to assess the differences in the cytokine expressions of CD4⁺ T cells in MG patients with AChR antibodies (AChR-MG) and the effect of immunosuppressive (IS) therapy on cytokine activity and to test these findings also in MG patients without detectable antibodies (SN-MG). Clinically diagnosed AChR-MG and SN-MG patients were included. The AChR-MG patients were grouped as IS-positive and -negative and compared with age- and sex-matched healthy controls. Peripheral blood mononuclear cells were used for ex vivo intracellular cytokine production, and subsets of CD4⁺ T cells and circulating follicular helper T (cTfh) cells were detected phenotypically by the expression of the chemokine and the costimulatory receptors. Thymocytes obtained from patients who had thymectomy were also analyzed. IL-21, IL-4, IL-10, and IL-17A productions in CD4⁺ T cells were increased in AChR-MG compared to those in healthy controls. IS treatment enhanced IL-10 and reduced IFN-γ production in AChR-MG patients compared to those in IS-negative patients. Increased IL-21 and IL-4 productions were also demonstrated in SN-MG patients. Among CD4⁺ T cells, Th17 cells were increased in both disease subgroups. Treatment induced higher proportions of Th2 cells in AChR-MG patients. Both CXCR5⁺ and CXCR5⁻ CD4⁺ T cells expressed higher programmed cell death protein 1 (PD-1) and inducible costimulatory (ICOS) in AChR-MG and SN-MG groups, mostly irrespective of the treatment. Based on chemokine receptors on CXCR5⁺PD-1⁺ in CD4⁺ T (cTfh) cells, in AChR-MG patients without treatment, the proportions of Tfh17 cells were higher than those in the treated group, whereas the Tfh1 cells were decreased compared with those in the controls. The relevance of CXCR5 and PD-1 in the pathogenesis of AChR-MG was also suggested by the increased presence of these molecules on mature CD4 single-positive thymocytes from the thymic samples. The study provides further evidence for the importance of IL-21, IL-17A, IL-4, and IL-10 in AChR-MG. Disease-related CD4⁺T cells are identified mainly as PD-1⁺ or ICOS⁺ with or without CXCR5, resembling cTfh cells in the circulation or probably in the thymus. AChR-MG and SN-MG seem to have some similar characteristics. IS treatment has distinctive effects on cytokine expression.

Targeting tumors with IL-21 reshapes the tumor microenvironment by proliferating PD-1intTim-3-CD8+ T cells

The lack of sufficient functional tumor-infiltrating lymphocytes in the tumor microenvironment (TME) is one of the primary indications for the poor prognosis of patients with cancer. In this study, we developed an Erbitux-based IL-21 tumor-targeting fusion protein (Erb-IL21) to prolong the half-life and improve the antitumor efficacy of IL-21. Compared with Erb-IL2, Erb-IL21 demonstrated much lower toxicity in vivo. Mechanistically, Erb-IL21 selectively expanded functional cytotoxic T lymphocytes but not dysfunctional CD8+ T cells in the TME. We observed that the IL-21-mediated antitumor effect largely depended on the existing intratumoral CD8+ T cells, instead of newly migrated CD8+ T cells. Furthermore, Erb-IL21 overcame checkpoint blockade resistance in mice with advanced tumors. Our study reveals that Erb-IL21 can target IL-21 to tumors and maximize the antitumor potential of checkpoint blockade by expending a subset of tumor antigen-specific CD8+ T cells to achieve effective tumor control.

Memory CD4+ T Cells in Immunity and Autoimmune Diseases

CD4⁺ T helper (Th) cells play central roles in immunity in health and disease. While much is known about the effector function of Th cells in combating pathogens and promoting autoimmune diseases, the roles and biology of memory CD4⁺ Th cells are complex and less well understood. In human autoimmune diseases such as multiple sclerosis (MS), there is a critical need to better understand the function and biology of memory T cells. In this review article we summarize current concepts in the field of CD4⁺ T cell memory, including natural history, developmental pathways, subsets, and functions. Furthermore, we discuss advancements in the field of the newly-described CD4⁺ tissue-resident memory T cells and of CD4⁺ memory T cells in autoimmune diseases, two major areas of important unresolved questions in need of answering to advance new vaccine design and development of novel treatments for CD4⁺ T cell-mediated autoimmune diseases.

Title: IL-10-producing T cells and their dual functions

Interleukin (IL)-10 is considered a prototypical anti-inflammatory cytokine, which significantly contributes to the maintenance and reestablishment of immune homeostasis. However, this classical view fails to fully describe the pleiotropic roles of IL-10. Indeed, IL-10 can also promote immune responses, e.g. by supporting B-cell and CD8⁺ T-cell activation. The reasons for these seemingly opposing functions are unclear to a large extent. Recent and previous studies suggest that the cellular source and the microenvironment impact the function of IL-10. However, studies addressing the mechanisms which determine whether IL-10 promotes inflammation or controls it have just begun. This review first summarizes the recent findings on the heterogeneity of IL-10 producing T cells and their impact on the target cells. Finally, we will propose two possible explanations for the dual functions of IL-10.

Functions and regulation of T cell-derived interleukin-10

Interleukin (IL)-10 is an essential anti-inflammatory cytokine and functions as a negative regulator of immune responses to microbial antigens. IL-10 is particularly important in maintaining the intestinal microbe-immune homeostasis. Loss of IL-10 promotes the development of inflammatory bowel disease (IBD) as a consequence of an excessive immune response to the gut microbiota. IL-10 also functions more generally to prevent excessive inflammation during the course of infection. Although IL-10 can be produced by virtually all cells of the innate and adaptive immune system, T cells constitute a non-redundant source for IL-10 in many cases. The various roles of T cell-derived IL-10 will be discussed in this review. Given that IL-10 is at the center of maintaining the delicate balance between effective immunity and tissue protection, it is not surprising that IL-10 expression is highly dynamic and tightly regulated. We summarize the environmental signals and molecular pathways that regulate IL-10 expression. While numerous studies have provided us with a deep understanding of IL-10 biology, the majority of findings have been made in murine models, prompting us to highlight gaps in our knowledge about T cell-derived IL-10 in the human system.

A benzoxazole derivative PO-296 inhibits T lymphocyte proliferation by the JAK3/STAT5 signal pathway

Immunosuppressants have shown striking achievements in treating autoimmune diseases in recent years. It is urgent to develop more immunosuppressants to provide more options for patients. PO-296 [2-(6-chlorobenzo[d]oxazol-2-yl)-4,5,6,7-tetrahydro-2H-indazol-3-ol] was identified as a novel benzoxazole derivative. We observed that it exhibits an obvious immunosuppressive activity to T lymphocytes. PO-296 significantly inhibited the proliferation of activated human T lymphocyte without cytotoxicity. Moreover, PO-296 did not affect the expression of cluster of differentiation (CD)-25 or CD69 but induced T lymphocyte cycle arrest in the G0/G1 phase. Furthermore, PO-296 inhibited interleukin (IL)-6, IL-17, and interferon gamma expression but had no effect on IL-2, IL-4, or IL-10. Yet, importantly, PO-296 inhibited the phosphorylation of signal transducer and activator of transcription 5 (STAT5), increased the phosphorylation of p70S6K, but did not affect the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/mitogen-activated protein kinase pathway. In conclusion, these findings indicate that PO-296 inhibits human activated T-lymphocyte proliferation by affecting the janus kinase 3 (JAK3)/STAT5 pathway. PO-296 possesses a potential lead compound for the design and development of new immunosuppressants for the treatment of autoimmune diseases.

Prediction of improved survival in patients with pancreatic cancer via IL-21 enhanced detection of mesothelin epitope-reactive T-cell responses

Most patients with pancreatic cancer present with extensive metastasis at diagnosis, with a 5-year survival rate of approximately 5%, despite chemotherapy and surgery. New treatment modalities are needed to improve survival. Mesothelin is a tumor-associated antigen (TAA) in patients with pancreatic cancer that could be used to gauge cellular immune responses directed against transformed cells since up to 100 percent of pancreatic ductal adenocarcinoma cells have been shown to strongly express mesothelin. A prospective, observational study was carried out in twenty-six, chemotherapy-naïve patients with resectable pancreatic ductal adenocarcinoma. Participants were between 48 and 81 years (median age: 64.5 years), 15 males and 11 females. All participants were clinically followed-up between 439 and 853 days post-surgery (n=14) or until death (n=12). Peripheral blood drawn on the day of surgery was stimulated with a mesothelin peptide pool (42 peptides, non-overlapping), individual mesothelin peptides, positive (anti-CD3 antibody, OKT3) and negative controls (medium) with or without adding IL-21. Kaplan-Meier estimators were used to gauge patients’ survival pattern in relation to mesothelin-specific IFN-γ responses. A survival benefit was linked with IFN-γ responses to peptides corresponding to mature mesothelin (p=0.018) and targeted recognition of the mesothelin_601-615 epitope (MQEALSGTPCLLGPG) (p=0.006) in the presence of IL-21. Conversely, production of high levels of IFN-γ to OKT3 stimulation with IL-21 conditioning was associated with reduced survival of patients (p=0.016). Gauging anti-Mesothelin- directed immune responses will aid to identify patients i) in need of a more intensive clinical follow-up and ii) who may benefit from immunotherapeutic approaches targeting mesothelin.

Transcriptional Analysis of the Guinea Pig Mucosal Immune Response to Intravaginal Infection with Herpes Simplex Virus Type 2

Genital herpes infection in guinea pigs closely models human infection but tools for immune characterization are limited. Immunity to HSV infection at the vaginal epithelial surface was characterized in guinea pigs using PCR-based array analysis of vaginal swab samples. IFNγ was one of the most significantly upregulated genes throughout the infection and over 40% of genes with significantly altered expression were linked to IFNγ based on INTERFEROME analysis. IFNγ transcripts and biologically active IFNγ at the genital mucosa were confirmed by RTPCR and IFNγ reporter cells. Gene ontology analysis revealed activation of many biological processes related to genital immunity shared by humans and mice demonstrating the similarities of the local immune response to primary genital HSV-2 infection in guinea pigs and other established models. This transcription-based array will be useful for dissection of immunity during reactivation from latency, an infection outcome that is not well recapitulated by other animal models.

IL-21 modulates memory and exhaustion phenotype of T-cells in a fatty acid oxidation-dependent manner

T-cell-based therapies represent a promising strategy for cancer treatment. In this context, cytokines are discussed as a bona fide instrument for fine-tuning T- cell biology. One promising candidate is the pleiotropic interleukin-21 (IL-21) with only little being known regarding its direct effects on human T-cells. Thus, we sought out to characterize the impact of IL-21 on T-cell metabolism, fitness, and differentiation. Culturing T-cells in presence of IL-21 elicited a metabolic skewing away from aerobic glycolysis towards fatty acid oxidation (FAO). These changes of the metabolic framework were paralleled by increased mitochondrial fitness and biogenesis. However, oxidative stress levels were not increased but rather decreased. Furthermore, elevated FAO and mitochondrial biomass together with enhanced antioxidative properties are linked to formation of longer lasting memory responses and less PD-1 expression. We similarly observed an IL-21-triggered induction of central memory-like T-cells and reduced levels of PD-1 on the cell surface. Taken together, IL-21 shifts T-cells towards an immunometabolic phenotype that has been associated with increased survivability and enhanced anti-tumor efficacy. In addition, our data reveals a novel interconnection between fatty acid metabolism and immune function regulated by IL 21.

Intestinal IFN-γ-producing type 1 regulatory T cells coexpress CCR5 and programmed cell death protein 1 and downregulate IL-10 in the inflamed guts of patients with inflammatory bowel disease

BACKGROUND

IL-10 is an anti-inflammatory cytokine required for intestinal immune homeostasis. It mediates suppression of T-cell responses by type 1 regulatory T (T_R1) cells but is also produced by CD25⁺ regulatory T (Treg) cells.

OBJECTIVE

We aimed to identify and characterize human intestinal T_R1 cells and to investigate whether they are a relevant cellular source of IL-10 in patients with inflammatory bowel diseases (IBDs).

METHODS

CD4⁺ T cells isolated from the intestinal lamina propria of human subjects and mice were analyzed for phenotype, cytokine production, and suppressive capacities. Intracellular IL-10 expression by CD4⁺ T-cell subsets in the inflamed guts of patients with IBD (Crohn disease or ulcerative colitis) was compared with that in cells from noninflamed control subjects. Finally, the effects of proinflammatory cytokines on T-cell IL-10 expression were analyzed, and IL-1β and IL-23 responsiveness was assessed.

RESULTS

Intestinal T_R1 cells could be identified by coexpression of CCR5 and programmed cell death protein 1 (PD-1) in human subjects and mice. CCR5⁺PD-1⁺ T_R1 cells expressed IFN-γ and efficiently suppressed T-cell proliferation and transfer colitis. Intestinal IFN-γ⁺ T_R1 cells, but not IL-7 receptor-positive T_H cells or CD25⁺ Treg cells, showed lower IL-10 expression in patients with IBDs. T_R1 cells were responsive to IL-23, and IFN-γ⁺ T_R1 cells downregulated IL-10 with IL-1β and IL-23. Conversely, CD25⁺ Treg cells expressed higher levels of IL-1 receptor but showed stable IL-10 expression.

CONCLUSIONS

We provide the first ex vivo characterization of human intestinal T_R1 cells. Selective downregulation of IL-10 by IFN-γ⁺ T_R1 cells in response to proinflammatory cytokines is likely to drive excessive intestinal inflammation in patients with IBDs.

Reverse plasticity: TGF-β and IL-6 induce Th1-to-Th17-cell transdifferentiation in the gut

Th17 cells are a heterogeneous population of pro-inflammatory T cells that have been shown to mediate immune responses against intestinal bacteria. Th17 cells are highly plastic and can transdifferentiate to Th1/17 cells or unconventional Th1 cells, which are highly pathogenic in animal models of immune-mediated diseases such as inflammatory bowel diseases. A recent European Journal of Immunology article by Liu et al. (Eur. J. Immunol. 2015. 45:1010-1018) showed, surprisingly, that Th1 cells have a similar plasticity, and could transdifferentiate to Th17 cells. Thus, IFN-γ-producing Th1 effector cells specific for an intestinal microbial antigen were shown to acquire IL-17-producing capacities in the gut in a mouse model of colitis, and in response to TGF-β and IL-6 in vitro. TGF-β induced Runx1, and together with IL-6 was shown to render the ROR-γt and IL-17 promoters in Th1 cells accessible for Runx1 binding. In this commentary, we discuss how this unexpected plasticity of Th1 cells challenges our view on the generation of Th1/17 cells with the capacity to co-produce IL-17 and IFN-γ, and consider possible implications of this Th1-to-Th17-cell conversion for therapies of inflammatory bowel diseases and protective immune responses against intracellular pathogens.

The Enigmatic Role of Viruses in Multiple Sclerosis: Molecular Mimicry or Disturbed Immune Surveillance?

Multiple sclerosis (MS) is a T cell driven autoimmune disease of the central nervous system (CNS). Despite its association with Epstein-Barr Virus (EBV), how viral infections promote MS remains unclear. However, there is increasing evidence that the CNS is continuously surveyed by virus-specific T cells, which protect against reactivating neurotropic viruses. Here, we discuss how viral infections could lead to the breakdown of self-tolerance in genetically predisposed individuals, and how the reactivations of viruses in the CNS could induce the recruitment of both autoaggressive and virus-specific T cell subsets, causing relapses and progressive disability. A disturbed immune surveillance in MS would explain several experimental findings, and has important implications for prognosis and therapy.

A huge body of evidence suggests that viral infections promote MS; however, no single causal virus has been identified. Multiple viruses could promote MS via bystander effects.

Molecular mimicry is an established pathogenic mechanism in selected autoimmune diseases. It is also well documented in MS, but its contribution to MS pathogenesis is still unclear.

Bystander activation upon viral infection could be involved in the generation of the autoreactive and potentially encephalitogenic T helper (Th)-1/17 central memory (Th1/17_CM) cells found in the circulation of patients with MS.

Autoreactive Th1/17_CM cells could expand at the cost of antiviral Th1_CM cells in patients with MS, in particular in those undergoing natalizumab therapy, because these cells are expected to compete for the same homeostatic niche.

Autoreactive Th1/17 cells and antiviral Th1 cells are recruited to the CSF of patients with MS following attacks, suggesting that viral reactivations in the CNS induce the recruitment of pathogenic Th1/17 cells. Autoreactive Th1/17 cells in the CNS might also induce de novo viral reactivations in a circuit of self-induced inflammation.

GWAS of self-reported mosquito bite size, itch intensity and attractiveness to mosquitoes implicates immune-related predisposition loci

Understanding the interaction between humans and mosquitoes is a critical area of study due to the phenomenal burdens on public health from mosquito-transmitted diseases. In this study, we conducted the first genome-wide association studies (GWAS) of self-reported mosquito bite reaction size (n = 84,724), itchiness caused by bites (n = 69,057), and perceived attractiveness to mosquitoes (n = 16,576). In total, 15 independent significant (P < 5×10⁻⁸) associations were identified. These loci were enriched for immunity-related genes that are involved in multiple cytokine signalling pathways. We also detected suggestive enrichment of these loci in enhancer regions that are active in stimulated T-cells, as well as within loci previously identified as controlling central memory T-cell levels. Egger regression analysis between the traits suggests that perception of itchiness and attractiveness to mosquitoes is driven, at least in part, by the genetic determinants of bite reaction size.

Our findings illustrate the complex genetic and immunological landscapes underpinning human interactions with mosquitoes.

Pharmacological Inhibition of Bromodomain Proteins Suppresses Retinal Inflammatory Disease and Downregulates Retinal Th17 Cells

Experimental autoimmune uveitis (EAU), in which CD4⁺ Th1 and/or Th17 cells are immunopathogenic, mimics various clinical features of noninfectious uveitis in humans. The impact of bromodomain extraterminal (BET) inhibitors on Th17 cell function was studied in a mouse model of EAU in vivo and in mouse and human Th17 cells in vitro. Two BET inhibitors (GSK151 and JQ1) were able to ameliorate the progression of inflammation in EAU and in mouse CD4⁺ T cells in vitro, downregulating levels of Th17 cells. Additionally, the uveitogenic capacity of Th17 cells to transfer EAU was abrogated by BET inhibitors in an adoptive transfer model. In human CD4⁺ T cells, a 5-d exposure to BET inhibitors was accompanied by a significant downregulation of Th17-associated genes IL-17A, IL-22, and retinoic acid-related orphan receptor γt. However, in vitro, the inhibitors had no effect on already polarized Th17 cells. The key finding is that, in response to BET inhibitors, Th17-enriched cultures developed a regulatory phenotype, upregulated FOXP3 expression and IL-10 secretion, and lost pathogenicity in vivo. We conclude that BET targeting of Th17 cells is a potential therapeutic opportunity for a wide range of inflammatory and autoimmune diseases, including uveitis.

Deficiency of the immunostimulatory cytokine IL-21 promotes intestinal neoplasia via dysregulation of the Th1/Th17 axis

IL-21 has reported activity in promoting both Th1 and Th17 immune responses. Its role in sporadic human colorectal cancer is unknown. We aimed to delineate the role of IL-21 in a model of sporadic intestinal carcinogenesis. We found that in APC^MIN/+ mice, ablation of IL-21 increased intestinal tumorigenesis. Expression of pro-inflammatory Th17-associated genes, including RORγt and IL-17A, was increased in the intestine in the absence of IL-21, while expression of antitumor Th1-associated genes Tbet, IFNγ, granzyme B, and perforin was decreased. Similarly, the IL-21-deficient APC^MIN/+ mouse intestines had fewer infiltrating T cells as well as decreased effector memory T cells, NK cells, and granzyme B-expressing cells. Finally, our data suggest that IL-21 impairs Th17 immune responses as mesenteric lymph nodes from IL-21-deficient mice had increased IL-17A expression, and naive helper T cells from IL-21-deficient mice were more prone to differentiate into IL-17A-secreting cells.

Uncontrolled IL-17 Production by Intraepithelial Lymphocytes in a Case of non-IPEX Autoimmune Enteropathy

Objectives:

To provide a functional and phenotypic characterization of immune cells infiltrating small intestinal mucosa during non-IPEX autoimmune enteropathy (AIE), as to gain insights on the pathogenesis of this clinical condition.

Methods:

Duodenal biopsies from a patient with AIE at baseline and following drug-induced remission were analyzed by immunohistochemistry, immunofluorescence, and flow cytometry, and results were compared with those obtained from patients with active celiac disease, ileal Crohn’s disease and healthy controls. Lamina propria (LP) and intraepithelial (IELs) lymphocytes from AIE and controls were analyzed for mechanisms regulating cytokine production. Foxp3 expression and suppressive functions of LP regulatory T cells (Tregs) were analyzed.

Results:

The quantitative deficit of Foxp3 expression in Tregs in AIE associates with unrestrained IL-17 production by IELs. Interleukin (IL)-17-producing IELs were rare in the uninflamed duodenum and in the ileum of Crohn’s disease patients, and disappeared upon drug-induced AIE remission. IL-17 upregulation in CD4⁺IELs and CD4⁺LP T cells had different requirements for pro-inflammatory cytokines. Moreover, transforming growth factor-β (TGF-β) selectively enhanced IL-17 production by CD8⁺IELs. Intriguingly, although Foxp3^lowTregs in AIE were poorly suppressive, they could upregulate GARP-LAP/TGF-β surface expression and enhanced IL-17 production selectively by CD8⁺IELs. Finally, phosphorylated Smad2/3 was detectable in duodenal CD8⁺ lymphocytes in active AIE in situ, indicating that they received signals from the TGF-β receptor in vivo.

Conclusions:

AIE is characterized by the appearance of unconventional IL-17-producing IELs, which could be generated locally by pro-inflammatory cytokines and TGF-β. These results suggest that Foxp3⁺Tregs and Treg-derived TGF-β regulate IL-17 production by IELs in the small intestine and in AIE.

IL-21 and T Cell Differentiation: Consider the Context

Accumulating studies demonstrate that IL-21 modulates the differentiation of various CD4 and CD8 T cell subsets and provide insights into the underlying cellular and molecular processes that are influenced by this cytokine. Intriguingly, the effects of IL-21 on T cells can be complex and vary depending on the experimental system used. We review our current understanding of the roles of IL-21 in the generation of phenotypically distinct CD4 and CD8 T cell populations and discuss the potential environmental cues, cellular factors, and molecular mediators that impact the actions of IL-21. We propose that IL-21 acts in a context-dependent manner to accentuate T cell subset development.

Advances of the interleukin-21 signaling pathway in immunity and angiogenesis

Interleukin-21 (IL-21) and its receptor (IL-21R) are broadly expressed on human B cells, activated T cells and other myeloid cells. IL-21 cooperates with IL-6 and transforming growth factor-β to regulate T-cell differentiation. IL-21-mediated human B cell and dendritic cells differentiation requires signal transducer and activator of transcription 3 (STAT3), and also induces B-cell apoptosis dependents on the Toll-like receptor signal. Recently, in vitro and in vivo experiments showed that IL-21/IL-21R regulate angiogenesis through STAT3. IL-21 signaling pathways are complex due to its cooperation with other transcriptional factors, such as interferon regulatory factor 4 and granulocyte-macrophage colony-stimulating factor. The Janus kinase-STAT pathway has been the most extensively studied. With the increase in the understanding of IL-21 biology in the context of each specific disease or pathological condition, IL-21 could be a new therapeutic target for immune-related disease.

PPARβ/δ directs the therapeutic potential of mesenchymal stem cells in arthritis

OBJECTIVES

To define how peroxisome proliferator-activated receptor (PPAR) β/δ expression level in mesenchymal stem cells (MSCs) could predict and direct both their immunosuppressive and therapeutic properties. PPARβ/δ interacts with factors such as nuclear factor-kappa B (NF-κB) and regulates the expression of molecules including vascular cell adhesion molecule (VCAM)-1 and intercellular adhesion molecule (ICAM)-1. Since these molecules are critical for MSC function, we investigated the role of PPARβ/δ on MSC immunosuppressive properties.

METHODS

We either treated human MSCs (hMSCs) with the irreversible PPARβ/δ antagonist (GSK3787) or derived MSCs from mice deficient for PPARβ/δ (PPARβ/δ^-/- MSCs). We used the collagen-induced arthritis (CIA) as model of immune-mediated disorder and the MSC-immune cell coculture assays.

RESULTS

Modulation of PPARβ/δ expression in hMSCs either using GSK3787 or hMSCs from different origin reveals that MSC immunosuppressive potential is inversely correlated with Ppard expression. This was consistent with the higher capacity of PPARβ/δ^-/- MSCs to inhibit both the proliferation of T lymphocytes, in vitro, and arthritic development and progression in CIA compared with PPARβ/δ^+/+ MSCs. When primed with proinflammatory cytokines to exhibit an immunoregulatory phenotype, PPARβ/δ^-/- MSCs expressed a higher level of mediators of MSC immunosuppression including VCAM-1, ICAM-1 and nitric oxide (NO) than PPARβ/δ^+/+ MSCs. The enhanced NO₂ production by PPARβ/δ^-/- MSCs was due to the increased retention of NF-κB p65 subunit on the κB elements of the inducible nitric oxide synthase promoter resulting from PPARβ/δ silencing.

CONCLUSIONS

Our study is the first to show that the inhibition or knockdown of PPARβ/δ in MSCs primes their immunoregulatory functions. Thus, the regulation of PPARβ/δ expression provides a new strategy to generate therapeutic MSCs with a stable regulatory phenotype.

HIV Skews the Lineage-Defining Transcriptional Profile of Mycobacterium tuberculosis-Specific CD4+ T Cells

HIV-infected persons are at greater risk of developing tuberculosis (TB) even before profound CD4 loss occurs, suggesting that HIV alters CD4(+) T cell functions capable of containing bacterial replication. An effective immune response to Mycobacterium tuberculosis most likely relies on the development of a balanced CD4 response, in which distinct CD4(+) Th subsets act in synergy to control the infection. To define the diversity of M. tuberculosis-specific CD4(+) Th subsets and determine whether HIV infection impacts such responses, the expression of lineage-defining transcription factors T-bet, Gata3, RORγt, and Foxp3 was measured in M. tuberculosis-specific CD4(+) T cells in HIV-uninfected (n = 20) and HIV-infected individuals (n = 20) with latent TB infection. Our results show that, upon 5-d restimulation in vitro, M. tuberculosis-specific CD4(+) T cells from healthy individuals have the ability to exhibit a broad spectrum of Th subsets, defined by specific patterns of transcription factor coexpression. These transcription factor profiles were skewed in HIV-infected individuals where the proportion of T-bet(high)Foxp3(+) M. tuberculosis-specific CD4(+) T cells was significantly decreased (p = 0.002) compared with HIV-uninfected individuals, a change that correlated inversely with HIV viral load (p = 0.0007) and plasma TNF-α (p = 0.027). Our data demonstrate an important balance in Th subset diversity defined by lineage-defining transcription factor coexpression profiles that is disrupted by HIV infection and suggest a role for HIV in impairing TB immunity by altering the equilibrium of M. tuberculosis-specific CD4(+) Th subsets.

Therapeutic Efficacy of Fresh, Autologous Mesenchymal Stem Cells for Severe Refractory Gingivostomatitis in Cats

Mesenchymal stem cells (MSCs) are a promising therapy for immune-mediated and inflammatory disorders, because of their potent immunomodulatory properties. In this study, we investigated the use of fresh, autologous, adipose-derived MSCs (ASCs) for feline chronic gingivostomatitis (FCGS), a chronic, debilitating, idiopathic, oral mucosal inflammatory disease. Nine cats with refractory FCGS were enrolled in this pilot study. Each cat received 2 intravenous injections of 20 million autologous ASCs, 1 month apart. Oral biopsies were taken before and at 6 months after the first ASC injection. Blood immune cell subsets, serum protein, and cytokine levels were measured at 0, 1, 3, and 6 months after treatment to assess immunomodulatory effects. Seven of the 9 cats completed the study. Five cats responded to treatment by either complete clinical remission (n=3) or substantial clinical improvement (n=2). Two cats were nonresponders. Cats that responded to treatment also exhibited systemic immunomodulation demonstrated by decreased numbers of circulating CD8+ T cells, a normalization of the CD4/CD8 ratio, decreased neutrophil counts, and interferon-γ and interleukin (IL)-1β concentration, and a temporary increase in serum IL-6 and tumor necrosis factor-α concentration. No clinical recurrence has occurred following complete clinical remission (follow-up of 6-24 months). In this study, cats with <15% cytotoxic CD8 T cells with low expression of CD8 (CD8lo) cells were 100% responsive to ASC therapy, whereas cats with >15% CD8lo cells were nonresponders. The relative absence of CD8lo cells may be a biomarker to predict response to ASC therapy, and may shed light on pathogenesis of FCGS and mechanisms by which ASCs decrease oral inflammation and affect T-cell phenotype.

SIGNIFICANCE

This study is the first to demonstrate the safety and efficacy of fresh, autologous, adipose-derived stem cell systemic therapy for a naturally occurring, chronic inflammatory disease in cats. The findings demonstrate that this therapy resulted in complete clinical and histological resolution or reduction in clinical disease severity and immune modulation in most cats. This study also identified a potentially useful biomarker that could dictate patient enrollment and shed light on immune modulation mechanism. As a naturally occurring animal model, FCGS also provides a strategic platform for potentially translatable therapy for the treatment of human oral inflammatory disease.

Common gamma chain cytokines in combinatorial immune strategies against cancer

Common γ chain (γC) cytokines, namely IL-2, IL-4, IL-7, IL-9, IL-15, and IL-21 are important for the proliferation, differentiation, and survival of lymphocytes that display antitumor activity, thus stimulating considerable interest for the use of cytokines in cancer immunotherapy. In this review, we will focus on the γC cytokines that demonstrate the greatest potential for immunotherapy, IL-2, IL-7, IL-15, and IL-21. We will briefly cover their biological function, potential applications in cancer therapy, and update on their use in combinatorial immune strategies for eradicating tumors and hematopoietic malignancies.

Signal Strength and Metabolic Requirements Control Cytokine-Induced Th17 Differentiation of Uncommitted Human T Cells

IL-17 production defines Th17 cells, which orchestrate immune responses and autoimmune diseases. Human Th17 cells can be efficiently generated with appropriate cytokines from precommitted precursors, but the requirements of uncommitted T cells are still ill defined. In standard human Th17 cultures, IL-17 production was restricted to CCR6(+)CD45RA(+) T cells, which expressed CD95 and produced IL-17 ex vivo, identifying them as Th17 memory stem cells. Uncommitted naive CD4(+) T cells upregulated CCR6, RORC2, and IL-23R expression with Th17-promoting cytokines but in addition required sustained TCR stimulation, late mammalian target of rapamycin (mTOR) activity, and HIF-1α to produce IL-17. However, in standard high-density cultures, nutrients like glucose and amino acids became progressively limiting, and mTOR activity was consequently not sustained, despite ongoing TCR stimulation and T cell proliferation. Sustained, nutrient-dependent mTOR activity also induced spontaneous IL-22 and IFN-γ production, but these cytokines had also unique metabolic requirements. Thus, glucose promoted IL-12-independent Th1 differentiation, whereas aromatic amino acid-derived AHR ligands were selectively required for IL-22 production. The identification of Th17 memory stem cells and the stimulation requirements for induced human Th17/22 differentiation have important implications for T cell biology and for therapies targeting the mTOR pathway.

Poor functional immune recovery in aged HIV-1-infected patients following successfully treatment with antiretroviral therapy

Aging is now a well-recognized characteristic of the HIV-infected population and both AIDS and aging are characterized by a deficiency of the T-cell compartment. The objective of the present study was to evaluate the impact of antiretroviral (ARV) therapy in recovering functional response of T cells to both HIV-1-specific ENV peptides (ENV) and tetanus toxoid (TT), in young and aged AIDS patients who responded to ARV therapy by controlling virus replication and elevating CD4(+) T cell counts. Here, we observed that proliferative response of T-cells to either HIV-1-specific Env peptides or tetanus toxoid (TT) was significantly lower in older antiretroviral (ARV)-treated patients. With regard to cytokine profile, lower levels of IFN-γ, IL-17 and IL-21, associated with elevated IL-10 release, were produced by Env- or TT-stimulated T-cells from older patients. The IL-10 neutralization by anti-IL-10 mAb did not elevate IFN-γ and IL-21 release in older patients. Finally, even after a booster dose of TT, reduced anti-TT IgG titers were quantified in older AIDS patients and it was related to both lower IL-21 and IFN-γ production and reduced frequency of central memory T-cells. Our results reveal that ARV therapy, despite the adequate recovery of CD4(+) T cell counts and suppression of viremia, was less efficient in recovering adequate immune response in older AIDS patients.

Glucocorticoid-induced leucine zipper governs the therapeutic potential of mesenchymal stem cells by inducing a switch from pathogenic to regulatory Th17 cells in a mouse model of collagen-induced arthritis

OBJECTIVE

Mesenchymal stem cells (MSCs) are potent immunosuppressive cells that have shown promise in the treatment of rheumatoid arthritis (RA). Deciphering the intrinsic characteristics of MSCs that correlate with their biologic activity will facilitate their clinical use. Recently, the role of glucocorticoid-induced leucine zipper (GILZ) in the development of RA has been documented. The aim of this study was to evaluate whether GILZ expression by MSCs may contribute to their therapeutic effect.

METHODS

MSCs were isolated from GILZ-deficient (GILZ(-/-) ) mice and wild-type mice. MSCs (1 × 10(6) cells) were injected twice via the tail vein into mice with collagen-induced arthritis (CIA).

RESULTS

In vitro, we showed that GILZ is a key factor involved in the immunosuppressive potential of MSCs. MSCs derived from GILZ(-/-) mice did not suppress the proliferation of CD4+ T cells and were less efficient than MSCs derived from WT mice in altering Th17 cell polarization. Thus, we investigated the role of GILZ in an experimental model of arthritis and demonstrated that although WT MSCs significantly reduced paw swelling in arthritic mice, GILZ(-/-) MSCs did not. Moreover, the magnitude of the effects of GILZ(-/-) MSCs on Th17 cell frequency was significantly lower than that of WT MSCs. The therapeutic effect of MSCs correlated with the generation of Treg cells bearing the CD4 + RORγt+IL-17(low) IL-10+ signature, and Th17 cell polarization was GILZ dependent.

CONCLUSION

This study demonstrates that GILZ has an essential role in the therapeutic effectiveness of MSCs in arthritis by favoring Th17 cell polarization toward a regulatory phenotype. Therefore, potentiation of GILZ expression in MSCs could represent a means to enhance their therapeutic effect in autoimmune diseases.

Human IL-21+IFN-γ+CD4+ T cells in nasal polyps are regulated by IL-12

In the previous study, we found that the levels of IL-21 in nasal polyps (NPs) were significantly increased and associated with polyp size and recurrence. However, it is unclear that the cell source of IL-21 and the regulation of IL-21 in NP tissues. In the present study, we isolated the lymphocytes from NP tissues, uncinate tissues and peripheral blood of patients with NPs. The cells were analyzed for cell surface markers, cytokines and transcriptional factors by flow cytometry. The results indicated that CD4⁺ T cells were the major IL-21-exprssing cells in NP tissues and the majority of IL-21 producing CD4⁺ T cells co-expressed IFN-γ or IL-17A. IL-21⁺IFN-γ⁺CD4⁺ T cells in NP tissues exhibited the features of both Tfh and Th1 cells which co-expressed significantly higher amount of CXCR5, ICOS, PD-1, Bcl-6 and T-bet than did IL-21⁺IFN-γ⁻CD4⁺ T cells (p < 0.05). Treatment of the lymphocytes from NP tissues with IL-12 enhanced the production of IL-21 and IFN-γ, especially the frequency of IL-21⁺IFN⁻γ⁺CD4⁺ T cells (p < 0.05). The blockade of IL-12 inhibited the production of IL-21 and IFN-γ (p < 0.05). These findings indicated that IL-12 positively enhanced the generation of IL-21⁺IFN-γ⁺CD4⁺ T cells having the features of both Tfh and Th1 cells in NP tissues.

IL-21 production by CD4+ effector T cells and frequency of circulating follicular helper T cells are increased in type 1 diabetes patients

AIMS/HYPOTHESIS

Type 1 diabetes results from the autoimmune destruction of insulin-secreting pancreatic beta cells by T cells. Despite the established role of T cells in the pathogenesis of the disease, to date, with the exception of the identification of islet-specific T effector (Teff) cells, studies have mostly failed to identify reproducible alterations in the frequency or function of T cell subsets in peripheral blood from patients with type 1 diabetes.

METHODS

We assessed the production of the proinflammatory cytokines IL-21, IFN-γ and IL-17 in peripheral blood mononuclear cells from 69 patients with type 1 diabetes and 61 healthy donors. In an additional cohort of 30 patients with type 1 diabetes and 32 healthy donors, we assessed the frequency of circulating T follicular helper (Tfh) cells in whole blood. IL-21 and IL-17 production was also measured in peripheral blood mononuclear cells (PBMCs) from a subset of 46 of the 62 donors immunophenotyped for Tfh.

RESULTS

We found a 21.9% (95% CI 5.8, 40.2; p = 3.9 × 10(-3)) higher frequency of IL-21(+) CD45RA(-) memory CD4(+) Teffs in patients with type 1 diabetes (geometric mean 5.92% [95% CI 5.44, 6.44]) compared with healthy donors (geometric mean 4.88% [95% CI 4.33, 5.50]). Consistent with this finding, we found a 14.9% increase in circulating Tfh cells in the patients (95% CI 2.9, 26.9; p = 0.016).

CONCLUSIONS/INTERPRETATION

These results indicate that increased IL-21 production is likely to be an aetiological factor in the pathogenesis of type 1 diabetes that could be considered as a potential therapeutic target.

Advances in IL-21 biology - enhancing our understanding of human disease

Cytokines play critical roles in regulating the development and function of immune cells. Cytokines function by binding specific multimeric receptor complexes and activating intracellular signaling pathways that often involve JAKs and STATs. In addition to contributing to immunity, when production of cytokines is perturbed, they can contribute to disease. IL-21 is a pleiotropic cytokine produced predominantly by CD4(+) T cells and NKT cells. Gene-targeting studies in mice and in vitro analyses of human and murine lymphocytes have revealed central roles of IL-21 in regulating effector functions of T cells, NK cells and B cells. However, recent discoveries of loss-of function mutations in IL21 or IL21R in humans have unveiled unexpected roles for IL-21 in immune regulation. This review will focus on recent advances in IL-21 biology that have highlighted its critical role in normal immunity and how dysregulated IL-21 production can lead to immunodeficiency and autoimmune conditions.

Plasticity of human CD4 T cell subsets

Human beings are exposed to a variety of different pathogens, which induce tailored immune responses and consequently generate highly diverse populations of pathogen-specific T cells. CD4(+) T cells have a central role in adaptive immunity, since they provide essential help for both cytotoxic T cell- and antibody-mediated responses. In addition, CD4(+) regulatory T cells are required to maintain self-tolerance and to inhibit immune responses that could damage the host. Initially, two subsets of CD4(+) helper T cells were identified that secrete characteristic effector cytokines and mediate responses against different types of pathogens, i.e., IFN-γ secreting Th1 cells that fight intracellular pathogens, and IL-4 producing Th2 cells that target extracellular parasites. It is now well established that this dichotomy is insufficient to describe the complexity of CD4(+) T cell differentiation, and in particular the human CD4 compartment contains a myriad of T cell subsets with characteristic capacities to produce cytokines and to home to involved tissues. Moreover, it has become increasingly clear that these T cell subsets are not all terminally differentiated cells, but that the majority is plastic and that in particular central memory T cells can acquire different properties and functions in secondary immune responses. In addition, there is compelling evidence that helper T cells can acquire regulatory functions upon chronic stimulation in inflamed tissues. The plasticity of antigen-experienced human T cell subsets is highly relevant for translational medicine, since it opens new perspectives for immune-modulatory therapies for chronic infections, autoimmune diseases, and cancer.

The pathogenic Th profile of human activated memory Th cells in early rheumatoid arthritis can be modulated by VIP

Our aim is to study the behavior of memory Th cells (Th17, Th17/1, and Th1 profiles) from early rheumatoid arthritis (eRA) patients after their in vitro activation/expansion to provide information about its contribution to RA chronicity. Moreover, we analyzed the potential involvement of vasoactive intestinal peptide (VIP) as an endogenous healing mediator. CD4(+)CD45RO(+) T cells from PBMCs of HD and eRA were activated/expanded in vitro in the presence/absence of VIP. FACS, ELISA, RT-PCR, and immunocytochemistry analyses were performed. An increase in CCR6(+)/RORC(+) cells and in RORC-proliferating cells and a decrease in T-bet-proliferating cells and T-bet(+)/RORC(+) cells were shown in eRA. mRNA expression of IL-17, IL-2, RORC, RORA, STAT3, and Tbx21 and protein secretion of IL-17, IFNγ, and GM-CSF were higher in eRA. VIP decreased the mRNA expression of IL-22, IL-2, STAT3, Tbx21, IL-12Rβ2, IL-23R, and IL-21R in HD and it decreased IL-21, IL-2, and STAT3 in eRA. VIP decreased IL-22 and GM-CSF secretion and increased IL-9 secretion in HD and it decreased IL-21 secretion in eRA. VPAC2/VPAC1 ratio expression was increased in eRA. All in all, memory Th cells from eRA patients show a greater proportion of Th17 cells with a pathogenic Th17 and Th17/1 profile compared to HD. VIP is able to modulate the pathogenic profile, mostly in HD. Our results are promising for therapy in the early stages of RA because they suggest that targeting molecules involved in the pathogenic Th17, Th17/1, and Th1 phenotypes and targeting VIP receptors could have a therapeutic effect modulating these subsets.

KEY MESSAGES

Th17 cells are more important than Th1 in the contribution to pathogenesis in eRA patients. Pathogenic Th17 and Th17/1 profile are abundant in activated/expanded memory Th cells from eRA patients. VIP decreases the pathogenic Th17, Th1, and Th17/1 profiles, mainly in healthy donors. The expression of VIP receptors is reduced in eRA patients respect to healthy donors, whereas the ratio of VPAC2/VPAC1 expression is higher.