Human in vitro-induced IL-17A+ CD8+ T-cells exert pro-inflammatory effects on synovial fibroblasts.

IL-17A+ CD8+ T-cells, termed Tc17 cells, have been identified at sites of inflammation in several immune-mediated inflammatory diseases. However, the biological function of human IL-17A+ CD8+ T-cells is not well characterized, likely due in part to the relative scarcity of these cells. Here, we expanded IL-17A+ CD8+ T-cells from healthy donor PBMC or bulk CD8+ T-cell populations using an in vitro polarization protocol. We show that T-cell activation in the presence of IL-1ß and IL-23 significantly increased the frequencies of IL-17A+ CD8+ T-cells, which was not further enhanced by IL-6, IL-2, or anti-IFNγ mAb addition. In vitro-generated IL-17A+ CD8+ T-cells displayed a distinct type-17 profile compared with IL-17A- CD8+ T-cells, as defined by transcriptional signature (IL17A, IL17F, RORC, RORA, MAF, IL23R, CCR6), high surface expression of CCR6 and CD161, and polyfunctional production of IL-17A, IL-17F, IL-22, IFNγ, TNFα, and GM-CSF. A significant proportion of in vitro-induced IL-17A+ CD8+ T-cells expressed TCRVα7.2 and bound MR1 tetramers indicative of MAIT cells, indicating that our protocol expanded both conventional and unconventional IL-17A+ CD8+ T-cells. Using an IL-17A secretion assay, we sorted the in vitro-generated IL-17A+ CD8+ T-cells for functional analysis. Both conventional and unconventional IL-17A+ CD8+ T-cells were able to induce pro-inflammatory IL-6 and IL-8 production by synovial fibroblasts from patients with psoriatic arthritis, which was reduced upon addition of anti-TNFα and anti-IL-17A neutralizing antibodies. Collectively, these data demonstrate that human in vitro-generated IL-17A+ CD8+ T-cells are biologically functional and that their pro-inflammatory function can be targeted, at least in vitro, using existing immunotherapy.

Characterization of pathogenic synovial IL-17A-producing CD8+ T cell subsets in collagen-induced arthritis.

Using a murine collagen-induced arthritis model, we characterized the heterogeneity of synovial CD8+ T cells based on the expression of chemokine receptors, cytokines, and nuclear transcription factors. Four subsets, i.e. CXCR3-CCR4- cells, CXCR3+CCR4- cells, CXCR3+CCR4+ cells, and CXCR3-CCR4+ cells, were present in synovial CD8+CD62L-CCR6+IL-23R+CCR10- T cells. CXCR3-CCR4- cells belonged to exhausted CD8+ T cells. CXCR3+CCR4- cells were Tc17.1 cells expressing both IL-17A and IFN-γ. CXCR3+CCR4+ cells were transitional Tc17.1 cells expressing IL-17A but lower IFN-γ, and CXCR3-CCR4+ cells were Tc17 cells expressing IL-17A but no IFN-γ. Transitional Tc17.1 cells can differentiate into Tc17.1 cells in vitro under the instruction of IL-12. Tc17.1 cells and transitional Tc17.1 cells strongly induced the expression of pro-inflammatory mediators in synovial fibroblasts, whereas Tc17 cells were less potent in doing so. IFN-γ was involved in the higher pathogenicity of Tc17.1 cells and transitional Tc17.1 cells on synovial fibroblasts. This study expands the understanding of Tc17 biology by unveiling the phenotypic and functional heterogeneity of synovial IL-17A-expressing CD8+ T cells. These heterogeneous IL-17A-expressing CD8+ T cells could be novel therapeutic targets in future arthritis treatment.

Hematopoietic stem and multipotent progenitor cells produce IL-17, IL-21 and other cytokines in response to TLR signals associated with late apoptotic products and augment memory Th17 and Tc17 cells in the bone marrow of normal and lupus mice.

We studied effects of early and late apoptotic (necroptotic) cell products, related damage associated alarmins and TLR agonists, on hematopoietic stem and progenitor cells (HSPC). Surprisingly, normal HSPC themselves produced IL-17 and IL-21 after 1½days of stimulation, and the best stimulators were TLR 7/8 agonist; HMGB1-DNA; TLR 9 agonist, and necroptotic B cells. The stimulated HSPC expressed additional cytokines/mediators, directly causing rapid expansion of IL-17(+) memory CD4 T (Th17), and CD8 T (Tc17) cells, and antigen-experienced IL-17(+) T cells with "naïve" phenotype. In lupus marrow, HSPC were spontaneously pre-stimulated by endogenous signals to produce IL-17 and IL-21. In contrast to HSPC, megakaryocyte progenitors (MKP) did not produce IL-17, and unlike HSPC, they could process and present particulate apoptotic autoantigens to augment autoimmune memory Th17 response. Thus abnormally stimulated primitive hematopoietic progenitors augment expansion of IL-17 producing immune and autoimmune memory T cells in the bone marrow, which may affect central tolerance.

Polarization of HIV-1- and CMV-Specific IL-17-Producing T Cells among People with HIV under Antiretroviral Therapy with Cannabis and/or Cocaine Usage.

OBJECTIVE: This study evaluated the influence of cannabis and/or cocaine use in human immunodeficiency virus (HIV)- and cytomegalovirus (CMV)-specific T-cell responses of people with HIV (PWH). RESULTS: There was a higher percentage of IL-17-producing HIV-Gag-specific CD8+ T-cells in all drug users than that in PWH non-drug users. Stratifying the drug-user groups, increased percentages of IL-17-producing HIV-Gag-specific CD4+ and CD8+ T-cells were found in PWH cannabis plus cocaine users compared to PWH non-drug users. In response to CMV, there were higher percentage of IL-17-producing CMV-specific CD8+ T-cell in PWH cocaine users than that in PWH non-drug users. Considering all drug users together, there was a higher percentage of SEB-stimulated IL-17-producing CD4+ T-cells than that in PWH non-drug users, whereas cannabis users had higher percentages of IL-17-producing CD4+ T-cells compared to non-drug users. METHODS: Cryopreserved peripheral blood mononuclear cells from 37 PWH undergoing antiretroviral therapy (ART) using cannabis (10), cocaine (7), or cannabis plus cocaine (10) and non-drug users (10) were stimulated with HIV-1 Gag or CMV-pp65 peptide pools, or staphylococcal enterotoxin B (SEB) and evaluated for IFN-γ- and/or IL-17A-producing CD4+ and CD8+ T-cells using flow cytometry. CONCLUSIONS: Cannabis plus cocaine use increased HIV-specific IL-17 producing T-cells and cocaine use increased IL-17 CMV-specific CD8+ T-cell responses which could favor the inflammatory conditions associated with IL-17 overproduction.

PD-1 limits differentiation and plasticity of Tc17 cells.

Blockade of surface co-inhibitory receptor programmed cell death-1 (PD-1; CD279) has been established as an important immunotherapeutic approach to treat malignancies. On a cellular level, PD-1 is demonstrated to be of particular importance in inhibiting differentiation and effector function of cytotoxic Tc1 cells (CTLs). Nevertheless, the role of PD-1 in modulating interleukin (IL)-17-producing CD8+ T-cells (Tc17 cells), which generally display suppressed cytotoxic nature, is not well understood. To evaluate the impact of PD-1 in Tc17 responses, we examined its functioning using different in vitro and in vivo models. Upon activation of CD8+ T-cells in Tc17 environment, we found that PD-1 was rapidly expressed on the surface of CD8+ T-cells and triggered a T-cell-internal mechanism that inhibited the expression of IL-17 and Tc17-supporting transcription factors pSTAT3 and RORγt. Expression of type17-polarising cytokine IL-21 and the receptor for IL-23 were also suppressed. Intriguingly, adoptively transferred, PD-1-/- Tc17 cells were highly efficient in rejection of established B16 melanoma in vivo and displayed Tc1 like characteristics ex vivo. When using IL-17A-eGFP reporter mice for in vitro fate tracking, IL-17A-eGFP expressing cells lacking PD-1 signaling upon re-stimulation with IL-12 quickly acquired Tc1 characteristics such as IFN-γ, and granzyme B expression, implicating lineage independent upregulation of CTL-characteristics that are needed for tumor control. In line with plasticity characteristics, absence of PD-1 signaling in Tc17 cells increased the expression of the stemness and persistence-associated molecules TCF1 and BCL6. Thus, PD-1 plays a central role in the specific suppression of Tc17 differentiation and its plasticity in relation to CTL-driven tumor rejection, which provides further explanation as to why the blockade of PD-1 is such an efficient therapeutic target for inducing tumor rejection.

Psoriatic and rheumatoid arthritis joints differ in the composition of CD8+ tissue-resident memory T cell subsets.

CD69+CD103+ tissue-resident memory T (TRM) cells are important drivers of inflammation. To decipher their role in inflammatory arthritis, we apply single-cell, high-dimensional profiling to T cells from the joints of patients with psoriatic arthritis (PsA) or rheumatoid arthritis (RA). We identify three groups of synovial CD8+CD69+CD103+ TRM cells: cytotoxic and regulatory T (Treg)-like TRM cells are present in both PsA and RA, while CD161+CCR6+ type 17-like TRM cells with a pro-inflammatory cytokine profile (IL-17A+TNFα+IFNγ+) are specifically enriched in PsA. In contrast, only one population of CD4+CD69+CD103+ TRM cells is detected and at similarly low frequencies in both diseases. Type 17-like CD8+ TRM cells have a distinct transcriptomic signature and a polyclonal, but distinct, TCR repertoire. Type 17-like cells are also enriched in CD8+CD103- T cells in PsA compared with RA. These findings illustrate differences in the immunopathology of PsA and RA, with a particular enrichment for type 17 CD8+ T cells in the PsA joint.

Interleukin-24 Limits Tumor-Infiltrating T Helper 17 Cell Response in Patients with Hepatitis B Virus-Related Hepatocellular Carcinoma.

Interleukin (IL)-24 is a multifunction cytokine in infectious diseases and cancers. IL-17-secreting CD4+ T (Th17) and CD8+ T (Tc17) cells promotes pathogenesis of hepatitis B virus (HBV)-associated liver disorders. However, the regulatory role of IL-24 to Th17/Tc17 cell response was not fully elucidated during HBV infection and HBV-hepatocellular carcinoma (HCC). In this study, plasma and peripheral blood mononuclear cells were isolated from 27 chronic hepatitis B (CHB) patients, 42 HBV-HCC patients and 17 normal controls (NC). Liver-infiltrating lymphocytes (LILs) were prepared from tumor and para-tumor tissues of 17 HBV-HCC patients, whereas CD4+ T cells in LILs were purified. LILs were stimulated with recombinant human IL-24. CD3+CD4+IL-17+ Th17 cells and CD3+CD8+IL-17+ Tc17 cells were investigated by flow cytometry. IL-24 level was measured by enzyme-linked immunosorbent assay. Purified CD4+ T cells were polarized for Th17 cells, and the regulatory role of IL-24 to liver-infiltrating Th17 polarization was assessed. There were no significant differences of peripheral Th17 or Tc17 cell percentage among NC, CHB, and HBV-HCC patients. Liver-infiltrating Th17 and Tc17 cell proportion was reduced in tumor tissues compared with para-tumor tissues. In contrast, plasma IL-24 level was increased in CHB and HBV-HCC patients. Exogenous IL-24 stimulation (10 or 100 ng/mL) in vitro downregulated of Th17 frequency and IL-17 secretion in LILs from both para-tumor and tumor tissues without affecting cellular proliferation or Tc17 percentage. Only 100 ng/mL of IL-24 inhibited tumor-infiltrating Th17 polarization, and this process was accompanied by suppression of nuclear factor-κB (NF-κB) and p38 mitogen-activated protein kinase phosphorylation. In conclusion, IL-24 might dampen Th17 cell response through NF-κB pathway in HBV-HCC tumor microenvironment. Elevated IL-24 might enhance anti-tumor immune response in HBV-HCC patients.

Distribution and Clinical Significance of IL-17A in Tumor-Infiltrating Lymphocytes of Non-Small Cell Lung Cancer Patients.

Objective: To investigate the distribution of IL-17A and its clinical significance in tumor infiltrating lymphocytes (TILs) of patients with non-small cell lung cancer (NSCLC). Methods: Expression level of IL-17A in TILs of 3 paired NSCLC and paracancerous specimens was measured by qRT-PCR. The distribution of IL-17A in immune cell subsets of 15 paired NSCLC and paracancerous specimens was examined by flow cytometry. The correlation between IL-17A and clinical features of NSCLC was identified. Results: IL-17A was significantly upregulated in TILs of NSCLC specimens than those of paracancerous ones (p < 0.0001). Meanwhile, T helper 17 cells (Th17 cells, p < 0.001), IL-17-secreting CD8+ T cells (Tc17 cells, p < 0.001) and IL-17-producing cells (γδT17 cells, p < 0.0001) were significantly abundant in TILs of NSCLC specimens than those of controls, and the higher abundance of the latter was much pronounced than that of the former two. Moreover, γδT17 cells in TILs were significantly correlated with lymphatic metastasis and CYFRA 21-1 level of NSCLC patients (p < 0.05). Conclusion: Tumor infiltrated γδT cells are the main source of IL-17 in early-stage NSCLC, and IL-17 may be a vital regulator involved in the development of NSCLC.

GM-CSF+ Tc17 cells are required to bolster vaccine immunity against lethal fungal pneumonia without causing overt pathology.

GM-CSF co-expressing T17 cells instigate pathologic inflammation during autoimmune disorders, but their function in immunity to infections is unclear. Here, we demonstrate the role of GM-CSF+Tc17 cells for vaccine immunity against lethal fungal pneumonia and the cytokine requirements for their induction and memory homeostasis. Vaccine-induced GM-CSF+ Tc17 cells are necessary to bolster pulmonary fungal immunity without inflating pathology. Although GM-CSF expressing Tc17 cells preferentially elevate during the memory phase, their phenotypic attributes strongly suggest they are more like Tc17 cells than IFNγ-producing Tc1 cells. IL-1 and IL-23, but not GM-CSF, are necessary to elicit GM-CSF+ Tc17 cells following vaccination. IL-23 is dispensable for memory Tc17 and GM-CSF+ Tc17 cell maintenance, but recall responses of effector or memory Tc17 cells in the lung require it. Our study reveals the beneficial, nonpathological role of GM-CSF+ Tc17 cells during fungal vaccine immunity.

Oncogenic role of Tc17 cells in cervical cancer development.

BACKGROUND: As one of the subsets of CD8+ T cells, Tc17 cells have recently been identified and are characterized by the secretion of interleukin (IL)-17, which is related to inflammatory diseases. AIM: To assess the status of Tc17 cells in cervical cancer and investigate the biological function of Tc17 cells in cervical cancer development. METHODS: Flow cytometry assay, immunohistochemistry, and immunofluorescence were performed to detect the levels and phenotype of Tc17 cells in blood and tumor samples from patients with cervical cancer. Prior to cell suspension culture, ELISA was carried out to measure the production of IL-6, IL-1ß, IL-23, CXCL12, and IL-17 in tumor tissue supernatant and co-cultured supernatant of patients with cervical cancer. In addition, multivariate analysis was performed to identify factors associated with overall survival using the Cox proportional hazards model. RESULTS: Compared with normal tissues, Tc17 cells specifically accumulated in tumor tissues of cervical cancer patients. Cancer cells produced a greater amount of IL-6, IL-1ß, and IL-23, which in turn promoted Tc17 cell polarization. Unlike the traditional cytotoxic CD8+ T cells, Tc17 cells secreted IL-17, which subsequently promoted CXCL12 expression in tumor cells, eventually enhancing the proliferation and migration of tumor cells. Thus, the ratio of tumor-infiltrating Tc17 cells was highly correlated with poor clinical outcome in patients with cervical cancer. CONCLUSION: Our data identified the oncogenic role of Tc17 cells in the development of cervical cancer. We propose that the ratio of Tc17 cells may be a useful index in the prognosis of patients with cervical cancer.

In Vitro-Generated Tc17 Cells Present a Memory Phenotype and Serve As a Reservoir of Tc1 Cells In Vivo.

Memory CD8+ T cells are ideal candidates for cancer immunotherapy because they can mediate long-term protection against tumors. However, the therapeutic potential of different in vitro-generated CD8+ T cell effector subsets to persist and become memory cells has not been fully characterized. Type 1 CD8+ T (Tc1) cells produce interferon-γ and are endowed with high cytotoxic capacity, whereas IL-17-producing CD8+ T (Tc17) cells are less cytotoxic but display enhanced self-renewal capacity. We sought to evaluate the functional properties of in vitro-generated Tc17 cells and elucidate their potential to become long lasting memory cells. Our results show that in vitro-generated Tc17 cells display a greater in vivo persistence and expansion in response to secondary antigen stimulation compared to Tc1 cells. When transferred into recipient mice, Tc17 cells persist in secondary lymphoid organs, present a recirculation behavior consistent with central memory T cells, and can shift to a Tc1 phenotype. Accordingly, Tc17 cells are endowed with a higher mitochondrial spare respiratory capacity than Tc1 cells and express higher levels of memory-related molecules than Tc1 cells. Together, these results demonstrate that in vitro-generated Tc17 cells acquire a central memory program and provide a lasting reservoir of Tc1 cells in vivo, thus supporting the use of Tc17 lymphocytes in the design of novel and more effective therapies.

Reconstitution of Th17, Tc17 and Treg cells after paediatric haematopoietic stem cell transplantation: Impact of interleukin-7.

Successful reconstitution of T lymphocytes after allogeneic haematopoietic stem cell transplantation (HSCT) is needed to establish the graft-versus-leukaemia effect and an effective anti-microbial defense, but the ratio between functionally different T-cell subsets needs to be balanced to avoid graft-versus-host disease (GVHD). IL-7 is essential for T-cell generation in the thymus and peripheral T-cell homeostasis. High IL-7 levels have been associated with impaired T-cell reconstitution, increased risk of acute GVHD and treatment-related mortality, but the underlying cellular mechanisms behind these associations have not been investigated previously. We hypothesized that increased levels of IL-7 post-transplant alters the balance between immune-regulatory T cell subsets during the post-transplant lymphocyte recovery towards a more pro-inflammatory profile. We quantified Th17 cells, Tc17 cells and Tregs in 29 children following HSCT. Th17 cell and Treg counts rose significantly from day +90 to +180 post-HSCT, and prior acute GVHD was associated with significant changes in the concentration of Tregs (9.4×106/L vs. 1.3×106/L, P=0.0052) and the Th17/Treg ratio (1.5 vs. 4.2, P=0.025). The plasma level of IL-7 at day +90 correlated inversely with Th17 cell counts (rs=-0.65, P=0.0002) and the proportion of Tc17 cells (rs=0.64, P=0.0005) at day +90, but not with Tregs. Furthermore, high IL-7 levels at day +7 were predictive of a less naïve T-cell phenotype at day +90. These findings add further evidence that IL-7 is a key regulatory factor that may tune the balance between functionally different T-cell subsets following HSCT.

Increased proportions of Tc17 cells and NK cells may be risk factors for disease progression in Hashimoto's thyroiditis.

Both cellular and humoral responses play important roles in the pathogenesis of Hashimoto's thyroiditis (HT). However, the immunological differences between euthyroid (mild HT) and hypothyroid (severe HT) patients are unknown. This study aimed to investigate the distribution of lymphocyte subsets and cytokine profiles in HT patients with differences in thyroid function. Peripheral blood was drawn from 18 healthy controls and 54 HT patients (33 patients with mild HT, 21 patients with severe HT). The percentages of B cell subsets, T cell subsets and NK cells were analyzed by flow cytometry. The levels of IL-21 and Bcl-6 mRNA were assessed using real-time PCR. The levels of serum IFN-γ, TNF-α, TGF-ß, IL-4, IL-6, IL-10 and a proliferation-inducing ligand (APRIL) were measured by ELISA or cytometric bead array. The percentages of double-negative memory B cells, plasma cells, Tfh cells and Tc17 cells were higher in HT patients than in the healthy controls. The percentages of Tc17 cells and NK cells were higher in the patients with severe HT than in the patients with mild HT. The levels of serum APRIL, IL-6 and IL-10 were higher in the patients with severe HT than in those with mild HT. The percentage of NK cells was positively correlated with TSH levels in the HT patients. Our data indicate that the distribution of lymphocyte subsets and cytokine profiles is aberrant in HT patients, and the increased percentages of Tc17 cells and NK cells and increased cytokine levels might be involved in the progression of HT.

Blockade of IL-23 ameliorates allergic lung inflammation via decreasing the infiltration of Tc17 cells.

INTRODUCTION: Tc17 cells are interleukin (IL)-17-producing CD8+ T cells and have been found to participate in the development of allergic asthma. Interleukin-23 is a cytokine that may be involved in modulating the IL-17 response via Th17 cells. This study aimed to investigate whether IL-23 also has immunomodulatory effects on Tc17 cells. MATERIAL AND METHODS: An allergic asthmatic mouse model was induced by sensitizing and challenging with ovalbumin (OVA). Anti-IL-23 antibody was administered intratracheally before challenge to the OVA-induced asthmatic mouse model. Airway hyperresponsiveness, lung inflammation, Tc17 cell percentages and IL-17 level in the lung tissue homogenate were measured. RESULTS: Anti-IL-23 treatment reduced airway hyperresponsiveness (Rn 2.471 ±0.5077 vs. 4.051 ±0.2334, p < 0.05), inflammatory cell infiltration in bronchoalveolar lavage fluid (eosinophils 140.0 ±9.869 vs. 222.4 ±31.55, p < 0.05, neutrophils 75.93 ±6.745 vs. 127.4 ±19.73, p < 0.05), airway inflammation and mucus secretion. Treatment with anti-IL-23 antibody also markedly reduced IL-17 level (398.1 ±28.74 vs. 590.6 ±36.13, p < 0.01) and percentage of Th17 and Tc17 cells in lung tissue homogenate (4.200 ±0.1581 vs. 9.314 ±1.027, p < 0.01 and 2.852 ±0.2566 vs. 5.588 ±0.3631, p < 0.01, Th17 and Tc17 cells respectively). CONCLUSIONS: Our data suggest that the IL-23/Tc17 cell axis may be involved in the pathogenesis of asthma as the complement of IL-23/Th17 cells.

Infiltration of IL-17-Producing T Cells and Treg Cells in a Mouse Model of Smoke-Induced Emphysema.

Chronic obstructive pulmonary disease (COPD) is a progressive and irreversible chronic inflammatory disease associated with the accumulation of activated T cells. To date, there is little information concerning the intrinsic association among Th17, Tc17, and regulatory T (Treg) cells in COPD. The objective of this study was to investigate the variation of lungs CD4(+)Foxp3(+) Treg cells and IL-17-producing CD4 and CD8 (Th17 and Tc17) lymphocytes in mice with cigarette-induced emphysema. Groups of mice were exposed to cigarette smoke or room air. At weeks 12 and 24, mice were sacrificed to observe histological changes by HE stain. The frequencies of Th17 (CD4(+)IL-17(+)T), Tc17 (CD8(+)IL-17(+)T), and Treg (CD4(+)Foxp3(+)T) cells in lungs from these mice were analyzed by flow cytometry. The mRNA levels of orphan nuclear receptor ROR γt and Foxp3 were performed by real-time quantitative polymerase chain reaction. The protein levels of interleukin-17 (IL-17), IL-6, IL-10, and transforming growth factor-beta (TGF-ß1) were measured by enzyme-linked immunosorbent assay. Cigarette smoke caused substantial enlargement of the air spaces accompanied by the destruction of the normal alveolar architecture and led to emphysema. The frequencies of Th17 and Tc17 cells, as well as the expressions of IL-6, IL-17, TGF-ß1, and ROR γt were greater in the lungs of cigarette smoke (CS)-exposed mice, particularly in the 24-week CS-exposed mice. The frequencies of Treg cells and the expressions of IL-10 and Foxp3 were lower in CS-exposed mice compared to control group. More important, the frequencies of Tregs were negatively correlated with Th17 cells and with Tc17 cells. Interestingly, a significant portion of the cells that infiltrate the lungs was skewed towards a Tc17 phenotype. Our findings suggest the contribution of Th17, Tc17, and Treg cells in the pathogenesis of COPD. Rebalance of these cells will be helpful for developing and refining the new immunological therapies for COPD.

Correlation of Tc17 cells at early stages after allogeneic hematopoietic stem cell transplantation with acute graft-versus-host disease.

Acute graft-versus-host disease (aGVHD) is associated with an immune dysregulation usually mediated by T lymphocytes. Recently, IL-17-producing T cells including Th17 and Tc17 cells have been implicated in immune-related diseases. However, their roles in aGVHD remain uncertain. In the study, we analyzed IL-17-producing cell recovery and association with the occurrence of aGVHD. While Th17 cells steadily recovered, Tc17 cell numbers remained unaltered during the first 3months after transplantation. Occurrence of aGVHD was correlated with increased level of Tc17 cells at the second months after allo-SCT. Interestingly, Tc17 cells were negatively associated with CD4+CD25+FOXP3+ regulatory T (Treg) cells, which was an important prognostic predictor in patients with aGVHD. In addition, we found that Tc17 numbers increased as the increased concentrations of TGF-ß and IL-6, which are known to drive Th17 polarization. These finding supported that Tc17 subset is involved in the immunopathology of aGVHD. Blocking the abnormally increased number of Tc17 may be a reasonable therapeutic strategy for aGVHD.

Vitamin D modulates different IL-17-secreting T cell subsets in multiple sclerosis patients.

Vitamin D deficiency is an environmental risk factor for MS, a Th17 cell-mediated autoimmune disease that results in demyelination in the CNS. Therefore, we aimed to evaluate the ability of in vitro 1,25(OH)2D in modulating different Th17 cell subsets in MS patients in remission phase. In the present study, the production of Th17-related cytokines (IL-1ß, IL-6, IL-17, IL-22), as well as GM-CSF, was significantly higher in cell cultures from MS patients than in healthy subjects (HS). The 1,25(OH)2D reduced all pro-inflammatory cytokines essayed, mainly those released from HS cell cultures. The proportion of both IL-17+IFN-γ+ (CD4+ and CD8+) T cells and IL-17+IFN-γ-CD8+ T cells was positively related with neurological disorders, determined by EDSS score. The addition of 1,25(OH)2D reduced not only these pathogenic T cell subsets but elevated the percentage of IL-10-secreting conventional (FoxP3+CD25+CD127-CD4+) and non-conventional (IL-17+) regulatory-like T cells. Taken together, the results indicate that the active form of vitamin D should benefit MS patients by attenuating the percentage of pathogenic T cells. This effect could be direct and/or indirect, by enhancing classical and non-classical regulatory T cells.

SUMO2 overexpression enhances the generation and function of interleukin-17-producing CD8⁺ T cells in mice.

Small ubiquitin-like modifier (SUMO) 2 is a small protein that controls the activity and stability of other proteins by SUMOylation. In this study, T cell-specific SUMO2 overexpressing transgenic mice were generated to study the effect of SUMO2 on T lymphocytes. SUMO2 overexpression promoted differentiation of interleukin (IL)-17-producing CD8(+) T cells, and significantly suppressed the growth of EL4 tumor cells in vivo. Moreover, the tumor tissue from SUMO2-overexpressing mice had higher interferon (IFN)-γ and granzyme B mRNA levels. Although SUMO2 overexpression did not increase IFN-γ or granzyme B production in cytotoxic T lymphocytes, IL-12 treatment restored and increased IFN-γ secretion in IL-17-producing CD8(+) T cells. SUMO2 overexpression also increased gene expression of chemokines, CCL4, and CXCL10, which attract cytotoxic T lymphocytes to tumor tissues. Additionally, SUMO2-overexpressing T cells exhibited increased STAT3 phosphorylation, implying a SUMO2 target which up-regulates STAT3 activity governing IL-17A-producing CD8(+) T cell differentiation and antitumor immune responses.

The prevalence and distribution of Th17 and Tc17 cells in patients with thyroid tumor.

Both Th17 and Tc17 cells have been found in various tumors and may play important roles in regulating anti-tumor immune responses. However, the prevalence and distribution of Th17 and Tc17 cells in thyroid tumors are still unclear. In the current study, we examined the percentages of Th17 and Tc17 cells in the peripheral blood of 31 thyroid adenoma and 11 thyroid carcinoma patients. The serum IL-17 levels were also examined and their associations with Th17 and Tc17 cells were evaluated. Moreover, the presence of Th17 cells was detected in both thyroid adenoma and carcinoma patients. Our results showed that compared with healthy individuals, patients with thyroid tumors had a higher proportion of Th17 and lower proportion of Tc17 cells in peripheral blood. The serum concentration of IL-17 was significantly increased in patients with thyroid tumors and it was correlated with the percent of Th17 cells. Furthermore, the number of Th17 cells was significantly increased in the tumors of the patients. Th17 and Tc17 cells were negatively correlated with the tumor size. There was no significant difference between thyroid adenoma and carcinoma patients. These results indicate that Th17 cells may contribute to thyroid tumor pathogenesis.

Effects of Tc17 Cells on Disease Severity and HBV-DNA Elimination in Patients with HBV Related Acute-on-chronic Liver Failure / 中山大学学报(医学科学版)

@#【Objective】To investigate the effects of Tc17 cells on disease severity and elimination of HBV-DNA in patients with HBV related acute-on-chronic liver failure（HBV-ACLF）.【Methods】Forty-three patients with HBV- ACLF were enrolled. Twenty patients with chronic hepatitis B（CHB）and 12 healthy subjects（NC）were enrolled as controls. Flow cytometry was used to detect the expression of peripheral Tc17 cells. HBV-DNA loads were measured，and the MELD，MELD-Na，CLIF-C ACLF and AARC scores were used to evaluate the disease severity. The effects of Tc17 cells on disease severity and decline of HBV-DNA were analyzed.【Results】Compared with NC group and CHB group， the expression of Tc17 cells in HBV-ACLF patients was significantly increased（P < 0.001 and P = 0.017）. Correlation analysis showed that Tc17 cells were positively correlated with AARC score，MELD score and MELD-Na score（r = 0.504，P = 0.001；r = 0.417，P = 0.005 and r = 0.382，P = 0.012），and a correlated trend was found with CLIF-C ACLF score（r = 0.294，P = 0.055）. And as the disease progressed，the expression of Tc17 cells gradually increased.In addition，Tc17 cells were positively correlated with HBV-DNA levels（r = 0.339，P = 0.026）at baseline，and the HBV-DNA levels were significantly decreased in patients with higher expression of Tc17 cells than in lower group after 4 weeks of treatment（P < 0.001）. Furthermore，it was found that baseline Tc17 cells and AST levels were associated with the HBV-DNA decline by multivariate linear regression analysis.【Conclusion】Tc17 cells-mediated inflammatory response helps clear the HBV-DNA，but excessive inflammatory response may aggravate the disease severity.