The multifaceted role of Th17 lymphocytes and their associated cytokines in cancer. Clin Dev Immunol. 2013;2013:957878. [PMID: 24454480 DOI: 10.1155/2013/957878]

Association between obesity and cancer risk in adults with HIV in Korea

INTRODUCTION

This study aimed to investigate the association between obesity and cancer risk as well as site-specific cancer risks in adults with HIV using a nationwide health screening database in Korea.

METHODS

Of the 16,671 adults with a new diagnosis of HIV from 2004 to 2020, 456 incident cancer cases and 1814 individually matched controls by sex, year of birth, year of HIV diagnosis, and follow-up duration (1 : 4 ratio) were included in this nested case-control study. The association between obesity (BMI ≥25 kg/m 2 ) and cancer risks was estimated and presented as odds ratios (ORs) and 95% confidence intervals (95% CIs).

RESULTS

Of the 456 cancer incident cases, there were 146 AIDS-defining cancer cases and 310 non-AIDS-defining cancer cases. Compared with nonobese adults with HIV, obese adults with HIV were at higher risk of non-AIDS-defining cancer (OR = 1.478, 95% CI = 1.118-1.955). Otherwise, the overall risk of AIDS-defining cancer (OR = 0.816, 95% CI = 0.520-1.279) and each type of AIDS-defining cancer (Kaposi sarcoma and non-Hodgkin's lymphoma) were not high in obese adults with HIV. Of the specific types of non-AIDS-defining cancers, obesity was associated with an increased risk of colorectal cancer (OR = 3.090, 95% CI = 1.110-8.604) and liver, bile duct, and pancreatic cancers (OR = 2.532, 95% CI = 1.141-5.617).

CONCLUSION

Obesity, which is one of the important health concerns in HIV management, was associated with an increased risk of non-AIDS-defining cancer but not AIDS-defining cancer.

Protein cargo in extracellular vesicles as the key mediator in the progression of cancer

Exosomes are small vesicles of endosomal origin that are released by almost all cell types, even those that are pathologically altered. Exosomes widely participate in cell-to-cell communication via transferring cargo, including nucleic acids, proteins, and other metabolites, into recipient cells. Tumour-derived exosomes (TDEs) participate in many important molecular pathways and affect various hallmarks of cancer, including fibroblasts activation, modification of the tumour microenvironment (TME), modulation of immune responses, angiogenesis promotion, setting the pre-metastatic niche, enhancing metastatic potential, and affecting therapy sensitivity and resistance. The unique exosome biogenesis, composition, nontoxicity, and ability to target specific tumour cells bring up their use as promising drug carriers and cancer biomarkers. In this review, we focus on the role of exosomes, with an emphasis on their protein cargo, in the key mechanisms promoting cancer progression. We also briefly summarise the mechanism of exosome biogenesis, its structure, protein composition, and potential as a signalling hub in both normal and pathological conditions. Video Abstract.

Activated platelet membrane nanovesicles recruit neutrophils to exert the antitumor efficiency

Platelets play a crucial role in the recruitment of neutrophils, mediated by P-selectin, CCL5, and ICAM-2. In this study, we prepared platelet membrane nanovesicles from activated platelets. Whether activated platelet membrane nanovesicles can recruit neutrophils has not been reported, nor has their role in antitumor immunity. The results of SDS-PAGE showed that the platelet membrane nanovesicles retained almost all the proteins of platelets. Western blotting showed that both the activated platelets and the platelet membrane nanovesicles expressed P-selectin, ICAM-2, and CCL5. In vivo results of a mouse model of breast cancer-transplanted tumor showed that tumor volume reduced significantly, Ki-67-positive tumor cells decreased, and TUNEL-positive tumor cells increased in tumors after treatment with activated platelet membrane nanovesicles (aPNs). After treatment with aPNs, not only the number of neutrophils, CD8⁺, CD4⁺ T cells, and B cells increased, but also IL-12, TNF-α, and IFN-γ levels elevated significantly in tumor tissues.

Consideration of possible effects of vitamin D on established cancer, with reference to malignant melanoma

Epidemiological studies indicate that Vitamin D has a beneficial, inhibitory effect on cancer development and subsequent progression, including melanoma (MM), and favourable MM outcome has been reported as directly related to vitamin D3 status, assessed by serum 25-hydroxyvitamin D3 (25[OH]D3 ) levels taken at diagnosis. It has been recommended that MM patients with deficient levels of 25(OH)D3 be given vitamin D3 . We examine possible beneficial or detrimental effects of treating established cancer with vitamin D3 . We consider the likely biological determinants of cancer outcome, the reported effects of vitamin D3 on these in both cancerous and non-cancerous settings, and how the effect of vitamin D3 might change depending on the integrity of tumour vitamin D receptor (VDR) signalling. We would argue that the effect of defective tumour VDR signalling could result in loss of suppression of growth, reduction of anti-tumour immunity, with potential antagonism of the elimination phase and enhancement of the escape phase of tumour immunoediting, possibly increased angiogenesis but continued suppression of inflammation. In animal models, having defective VDR signalling, vitamin D3 administration decreased survival and increased metastases. Comparable studies in man are lacking but in advanced disease, a likely marker of defective VDR signalling, studies have shown modest or no improvement in outcome with some evidence of worsening. Work is needed in assessing the integrity of tumour VDR signalling and the safety of vitamin D3 supplementation when defective.

CAR-T Cell Performance: How to Improve Their Persistence?

Adoptive cell therapy with T cells reprogrammed to express chimeric antigen receptors (CAR-T cells) has been highly successful in patients with hematological neoplasms. However, its therapeutic benefits have been limited in solid tumor cases. Even those patients who respond to this immunotherapy remain at risk of relapse due to the short-term persistence or non-expansion of CAR-T cells; moreover, the hostile tumor microenvironment (TME) leads to the dysfunction of these cells after reinfusion. Some research has shown that, in adoptive T-cell therapies, the presence of less differentiated T-cell subsets within the infusion product is associated with better clinical outcomes. Naive and memory T cells persist longer and exhibit greater antitumor activity than effector T cells. Therefore, new methods are being studied to overcome the limitations of this therapy to generate CAR-T cells with these ideal phenotypes. In this paper, we review the characteristics of T-cell subsets and their implications in the clinical outcomes of adoptive therapy with CAR-T cells. In addition, we describe some strategies developed to overcome the reduced persistence of CAR T-cells and alternatives to improve this therapy by increasing the expansion ability and longevity of modified T cells. These methods include cell culture optimization, incorporating homeostatic cytokines during the expansion phase of manufacturing, modulation of CAR-T cell metabolism, manipulating signaling pathways involved in T-cell differentiation, and strategies related to CAR construct designs.

The role of Th17 cells in the pathogenesis and treatment of breast cancer

Breast cancer is a severe problem worldwide due to an increase in mortality and prevalence among women. Despite early diagnostic procedures as well as advanced therapies, more investigation is required to find new treatment targets. Various factors and mechanisms, such as inflammatory conditions, can play a crucial role in cancer progression. Among them, Th17 cells are identified as effective CD4+ T cells that play an essential role in autoimmune diseases and inflammation which may be associated with anti-tumor responses. In addition, Th17 cells are one of the main factors involved in cancer, especially breast cancer via the inflammatory process. In tumor immunity, the exact mechanism of Th17 cells is not entirely understood and seems to have a dual function in tumor development. Various studies have reported that cytokines secreted by Th17 cells are in close relation to cancer stem cells and tumor microenvironment. Therefore, they play a critical role in the growth, proliferation, and invasion of tumor cells. On the other hand, most studies have reported that T cells suppress the growth of tumor cells by the induction of immune responses. In patients with breast cancer compared to normal individuals, various studies have been reported that the Th17 population dramatically increases in peripheral blood which results in cancer progression. It seems that Th17 cells by creating inflammatory conditions through the secretion of cytokines, including IL-22, IL-17, TNF-α, IL-21, and IL-6, can significantly enhance breast cancer progression. Therefore, to identify the mechanisms and factors involved in the activation and development of Th17 cells, they can provide an essential role in preventing breast cancer progression. In the present review, the role of Th17 cells in breast cancer progression and its therapeutic potential was investigated.

Melanoma Immunotherapy and Precision Medicine in the Era of Tumor Micro-Tissue Engineering: Where Are We Now and Where Are We Going?

Malignant melanoma still remains a cancer with very poor survival rates, although it is at the forefront of personalized medicine. Most patients show partial responses and disease progressed due to adaptative resistance mechanisms, preventing long-lasting clinical benefits to the current treatments. The response to therapies can be shaped by not only taking into account cancer cell heterogeneity and plasticity, but also by its structural context as well as the cellular component of the tumor microenvironment (TME). Here, we review the recent development in the field of immunotherapy and target-based therapy and how, in the era of tumor micro-tissue engineering, ex-vivo assays could help to enhance our melanoma biology knowledge in its complexity, translating it in the development of successful therapeutic strategies, as well as in the prediction of therapeutic benefits.

Alterations in Th17 and Treg Lymphocyte Subset in Workers Occupationally Exposed to Lead

Occupational exposure to lead (Pb) may have a deleterious effect on health of the workers. Among the various physiological systems, the immune system is one of the most susceptible targets of lead. Previous studies have been inconclusive in establishing the effect of Pb on the immune system. With this background, the aim of our study was to determine the effect of occupational Pb exposure on workers' immune parameters. A total of 110 individuals who were occupationally exposed to Pb and 97 apparently healthy non-exposed individuals were recruited in this study. Blood lead levels (BLL) were determined by atomic absorption spectrophotometry (AAS). Lymphocyte subsets (Th1, Th17, and Tregs) were analyzed using flow cytometry, and the cytokine levels (IL-2, IL-4, IL-6, IL-10, IL-17, and TNF-α) were determined by ELISA. BLL were found to be significantly higher in the exposed group than non-exposed. A significant increase of CD8 cells (%) was observed in the lead-exposed group, while CD4 cells (%), although higher in the exposed group did not differ significantly. Among the T lymphocyte subsets, proportion of Th1 and Tregs was found to be lower in the exposed group with a significant increase in Th17 (%). Additionally, the levels of estimated cytokines suggested a predominant pro-inflammatory response in Pb-exposed workers with significant increase in IL-4, IL-6, and TNF-α, and a significant decrease in IL-2 and IL-10. IL-17 levels did not show any significant difference between the two groups. Increased Th17/Tregs ratio in the exposed group is also suggestive of an increased pro-inflammatory immune response in the exposed group. In conclusion, Pb exposure may induce functional alteration in the immune cells, which may predispose to other abnormalities.

GFI1/HDAC1-axis differentially regulates immunosuppressive CD73 in human tumor-associated FOXP3+ Th17 and inflammation-linked Th17 cells

Plasticity between Th17 and Treg cells is regarded as a crucial determinant of tumor-associated immunosuppression. Classically Th17 cells mediate inflammatory responses through production of cytokine IL17. Recently, Th17 cells have also been shown to acquire suppressive phenotypes in tumor microenvironment. However, the mechanism by which they acquire such immunosuppressive properties is still elusive. Here, we report that in tumor microenvironment Th17 cell acquires immunosuppressive properties by expressing Treg lineage-specific transcription factor FOXP3 and ectonucleotidase CD73. We designate this cell as Th17reg cell and perceive that such immunosuppressive property is dependent on CD73. It was observed that in classical Th17 cell, GFI1 recruits HDAC1 to change the euchromatin into tightly-packed heterochromatin at the proximal-promoter region of CD73 to repress its expression. Whereas in Th17reg cells GFI1 cannot get access to CD73-promoter due to heterochromatin state at its binding site and, thus, cannot recruit HDAC1, failing to suppress the expression of CD73.

Organotypic Modeling of the Tumor Landscape

Cancer is a complex disease and it is now clear that not only epithelial tumor cells play a role in carcinogenesis. The tumor microenvironment is composed of non-stromal cells, including endothelial cells, adipocytes, immune and nerve cells, and a stromal compartment composed of extracellular matrix, cancer-associated fibroblasts and mesenchymal cells. Tumorigenesis is a dynamic process with constant interactions occurring between the tumor cells and their surroundings. Even though all connections have not yet been discovered, it is now known that crosstalk between actors of the microenvironment drives cancer progression. Taking into account this complexity, it is important to develop relevant models to study carcinogenesis. Conventional 2D culture models fail to represent the entire tumor microenvironment properly and the use of animal models should be decreased with respect to the 3Rs rule. To this aim, in vitro organotypic models have been significantly developed these past few years. These models have different levels of complexity and allow the study of tumor cells alone or in interaction with the microenvironment actors during the multiple stages of carcinogenesis. This review depicts recent insights into organotypic modeling of the tumor and its microenvironment all throughout cancer progression. It offers an overview of the crosstalk between epithelial cancer cells and their microenvironment during the different phases of carcinogenesis, from the early cell autonomous events to the late metastatic stages. The advantages of 3D over classical 2D or in vivo models are presented as well as the most promising organotypic models. A particular focus is made on organotypic models used for studying cancer progression, from the less complex spheroids to the more sophisticated body-on-a-chip. Last but not least, we address the potential benefits of these models in personalized medicine which is undoubtedly a domain paving the path to new hopes in terms of cancer care and cure.

Comparative Analysis of Immunoactivation by Nanosecond Pulsed Electric Fields and PD-1 Blockade in Murine Hepatocellular Carcinoma

Nanosecond pulsed electric field (NsPEF) ablation effectively eliminates early-stage hepatocellular carcinoma (HCC) by local ablation and advanced HCC by inducing a remarkable and sustained host immune response. However, this approach is not sufficient to prevent cancer progression, and complementary approaches are necessary for effective immunotherapy. In this study, we evaluated the immunoactivating effects and mechanisms of action of nsPEF ablation and PD-1 blockade on an HCC orthotopic xenograft mouse model. Briefly, 24 C57BL-6J tumor-bearing mice were randomly assigned to three groups: nsPEF ablation group, anti-PD-1 administration group, and untreated control group. Tumor-infiltrating T, B, and NK cell levels and plasma concentrations of Th1 (IL-2, IFN-γ, and TNF-α), Th2 (IL-4, IL-5, IL-6, and IL-10), Th9 (IL-9), and Th17 (IL-17A, IL-17F, IL-21, and IL-22) cytokines were evaluated. Both nsPEF ablation and anti-PD-1 treatment induced immune cell infiltration in local tumors and modulated cytokine levels in the peripheral blood, with distinct changes in the two treatment groups. Based on these findings, both nsPEF ablation and PD-1 antibody administration can trigger a local and systemic immune response in a partially complementary manner, and nsPEF ablation should be considered along with PD-1 blockade for the treatment of HCC.

Infiltration of γ⁢δ T cells, IL-17+ T cells and FoxP3+ T cells in human breast cancer

BACKGROUND

Tumor-infiltrating lymphocytes (TILs) have a strong prognostic value in various forms of cancers. These data often refer to use of the pan-T cell marker CD3, or the cytotoxic T lymphocyte marker CD8α. However, T cells are a heterogeneous group of cells with a wide array of effector mechanisms ranging from immunosuppression to cytotoxicity.

OBJECTIVE

In this study we have investigated the prognostic effects of some unconventional T cell subtypes in breast cancer; γ⁢δ T cells, IL-17+ T cells and FoxP3+ T cells (Tregs) in relation to the conventional CD3 and CD8α T cell markers.

METHODS

This was done using immunohistochemistry on a human breast cancer tissue microarray consisting of 498 consecutive cases of primary breast cancer.

RESULTS

Infiltration of γ⁢δ T cells and T cell infiltration in general (CD3), correlated with a good prognosis, while Treg infiltration with a worse. Infiltration of γ⁢δ T cells was associated with a significantly improved clinical outcome in all breast cancer subtypes except triple negative tumors. Only infiltration of either CD3+ or CD8α+ cells was independently associated with better prognosis for all breast cancer patients.

CONCLUSIONS

This study sheds further light on the prognostic impact of various T cell subtypes in breast cancer.

Obesity and Cancer: Existing and New Hypotheses for a Causal Connection

Existing explanations of obesity-associated cancer emphasise direct mutagenic effects of dietary components or hormonal imbalance. Some of these hypotheses are reviewed briefly, but recent evidence suggests a major role for chronic inflammation in cancer risk, possibly involving dietary content. These ideas include the inflammation-induced activation of the kynurenine pathway and its role in feeding and metabolism by activation of the aryl hydrocarbon receptor (AHR) and by modulating synaptic transmission in the brain. Evidence for a role of the kynurenine pathway in carcinogenesis then provides a potentially major link between obesity and cancer. A second new hypothesis is based on evidence that serine proteases can deplete cells of the tumour suppressors Deleted in Colorectal Cancer (DCC) and neogenin. These enzymes include mammalian chymotryptic proteases released by pro-inflammatory neutrophils and macrophages. Blood levels of chymotrypsin itself increase in parallel with food intake. The mechanistically similar bacterial enzyme subtilisin is widespread in the environment, animal probiotics, meat processing and cleaning products. Simple public health schemes in these areas, with selective serine protease inhibitors and AHR antagonists and could prevent a range of intestinal and other cancers.

Elevated IL-17A and IL-22 regulate expression of inducible CD38 and Zap-70 in chronic lymphocytic leukemia

BACKGROUND

In this study, we investigated the role and expression of interleukin (IL)-17A and IL-22 in chronic lymphocytic leukemia.

METHODS

We evaluated the expression of markers above on CLL by ELISA, qRT-PCR, flow cytometric analysis and nonparametric Kruskal-Wallis test.

RESULTS

Quantitative RT-PCR revealed that the mRNA levels of IL-17A and IL-22 in PBMCs of CLL patients were upregulated compared with those from healthy subjects (mean ± SD: 1.96 ± 0.232 vs.0.72 ± 0.15, P < 0.001 and mean ± SD: 2.45 ± 0.534 vs.0.81 ± 0.26, P < 0.001, respectivily). In addition, findings showed that the IL-17A and IL-22 plasma level was significantly elevated than that from healthy control group (P  < 0.001). The median IL-17A and IL-22 in CLL patients and healthy control group were 48.28 ± 17.2 pg mL-1 ; 20.01 ± 11.16 pg mL-1 and 58.68 ± 23.4 pg mL-1 ;16.47 ± 10.31 P < 0.001, respectively. The levels of IL-17A and IL-22 was not significantly associated with the different stages of disease (Rai stages; Kruskal-Wallis test P > 0.05).No significant relationship was found between expression of CD38 and higher median serum levels of IL-17A in patients, but patients with negative expression of ZAP-70 showed a significant association with higher median serum levels of IL-17A compared with healthy subjects. (57.84 pg mL-1 vs. 31.67 pg mL-1 ; P = 0.016).

CONCLUSION

IL-22 is elevated and associated with CD38 and Zap-70 expression in patients with CLL. No significant correlation was found between expression of CD38 and increased levels of IL-17A, negative expression of ZAP-70 showed a significant association with increased levels of IL-17A. © 2016 International Clinical Cytometry Society.

Circulating regulatory T cell subsets predict overall survival of patients with unresectable pancreatic cancer

Most patients with pancreatic ductal adenocarcinoma (PDAC) have unresectable cancers with a dismal prognosis, in which cohort chemotherapy is the primary treatment. T cell immune adaption is critical for tumor immune escape and prognosis of this disease. The present study aimed to determine the correlation between peripheral T cell subset distribution in patients with unresectable PDAC and their response to chemotherapy. Two hundred and twelve patients with unresectable PDAC were included whose blood samples were collected for analysis of T cell subsets, including CD3+, CD4+, CD8+, CD8+CD28+ and CD4+CD25+CD127 T cells by flow cytometry before and after gemcitabine-based chemotherapy. Enzyme-linked immunosorbent assay was used to detect the expression levels of tumor growth factor (TGF)-β1, interleukin (IL)-6 and IL-17A in the patients before and after chemotherapy. Univariate and multivariate analyses found that an initial CD4/CD8 ratio or T regulatory (Treg) cell level before any treatment was associated with the prognosis of unresectable PDAC. After two cycles of chemotherapy, there was no significant change in percentages of T cell subsets, except elevation to a higher level of CD3+ T cells. Decreased Tregs or CD4/CD8 ratio after two cycles of chemotherapy predicts a longer overall survival (OS). Levels of Tregs in stable disease (SD) and partial remission (PR) cases significantly decreased after chemotherapy, but increased in progressive disease (PD) patients. There was no correlation between Tregs and the expression level of either TGF-β1 or IL-6. IL-17A expression was elevated in Treg-decreased patients, whereas IL-17A was reduced in Treg-increased patients after chemotherapy. The circulating signature of T cell subsets can predict OS and chemotherapeutic response in patients with unresectable PDAC, and may be attributable to the plasticity of T cell subsets.

Search for biomarkers of asbestos exposure and asbestos-induced cancers in investigations of the immunological effects of asbestos

The immunological effects of asbestos exposure on various lymphocytes such as the regulatory T cell (Treg), responder CD4+ T helper cell (Tresp), CD8+ cytotoxic T lymphocytes (CTL), and natural killer (NK) cells were investigated. Results show that asbestos exposure impairs antitumor immunity through enhancement of regulatory T cell function and volume, reduction of CXCR3 chemokine receptor in responder CD4+ T helper cells, and impairment of the killing activities of CD8+ cytotoxic T lymphocytes (CTL) and NK cells. These findings were used to explore biological markers associated with asbestos exposure and asbestos-induced cancers and suggested the usefulness of serum/plasma IL-10 and TGF-β, surface CXCR3 expression in Tresp, the secreting potential of IFN-γ in Tresp, intracellular perforin level in CTL, and surface expression NKp46 in NK cells. Although other unexplored cytokines in serum/plasma and molecules in these immunological cells, including Th17, should be investigated by experimental procedures in addition to a comprehensive analysis of screening methods, biomarkers based on immunological alterations may be helpful in clinical situations to screen the high-risk population exposed to asbestos and susceptible to asbestos-related cancers such as mesothelioma.

Induction of IL-17 production from human peripheral blood CD4+ cells by asbestos exposure

We have previously reported that chronic, recurrent and low-dose exposure to asbestos fibers causes a reduction in antitumor immunity. Investigation of natural killer (NK) cells using an in vitro cell line model and comprising in vitro activation using freshly isolated NK cells co-cultured with chrysotile fibers, as well as NK cells derived from asbestos-exposed patients with pleural plaque (PP) or malignant mesothelioma (MM), revealed decreased expression of NK cell activating receptors such as NKG2D, 2B4 and NKp46. An in vitro differentiation and clonal expansion model for CD8+ cytotoxic T lymphocytes (CTLs) showed reduced cytotoxicity with decreased levels of cytotoxic molecules such as granzyme B and perforin, as well as suppressed proliferation of CTLs. Additionally, analysis of T helper cells showed that surface CXCR3, chemokine receptor, and the productive potential of interferon (IFN)γ were reduced following asbestos exposure in an in vitro cell line model and in peripheral CD4+ cells of asbestos-exposed patients. Moreover, experiments revealed that asbestos exposure enhanced regulatory T cell (Treg) function. This study also focused on CXCR3 expression and the Th-17 cell fraction. Following activation with T-cell receptor and co-culture with various concentrations of chrysotile fibers using freshly isolated CD4+ surface CXCR3 positive and negative fractions, the intracellular expression of CXCR3, IFNγ and IL-17 remained unchanged when co-cultured with chrysotile. However, subsequent re-stimulation with phorbol 12-myristate 13-acetate (PMA) and ionomycin resulted in enhanced IL-17 production and expression, particularly in CD4+ surface CXCR3 positive cells. These results indicated that the balance and polarization between Treg and Th-17 fractions play an important role with respect to the immunological effects of asbestos and the associated reduction in antitumor immunity.

Significance of Th17/Treg balance in pathogenesis and treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in China, and it is characterized by high malignancy, rapid progression, and easy metastasis. Current treatment options include liver transplantation, surgical resection and local ablative therapy. However, for all except transplantation, tumor recurrence rates are up to 70% after 5 years. In recent years, due to unsatisfying therapeutic effects of conventional therapies, the immune therapy of HCC has gradually become a hot research area. However, there exists a severe tumor immune microenvironment in HCC, which affects the immune therapeutic effects. Regulatory T (Treg) cells and T helper 17 (Th17) cells are two newly discovered subsets of CD4⁺ T cells. They play crucial roles in the maintenance of immune homeostasis and antitumor immunity, and they are important in forming microenvironmental immune suppression in HCC. Immunotherapy targeting Th17 or Treg cells in HCC appears to have potential feasibility. More evidence show that clarification of Th17/Treg balance and imbalance mechanisms may provide a new strategy for the immunotherapy of HCC.

Generation and Expansion of T Helper 17 Lymphocytes Ex Vivo

CD4(+) T helper (Th) lymphocytes are essential elements of the complex cellular networks regulating the initiation, development, and termination of adaptive immune responses. Different independent and specialized subsets of Th cells can be distinguished based on their dedicated transcription factor and cytokine expression profiles. Th17 lymphocytes have been described about a decade ago as CD4(+) Th cells producing high quantity of IL-17A as a signature cytokine. Since their initial discovery, Th17 have drawn intense scrutiny for their dominant role in the pathogenesis of multiple autoimmune, infectious diseases and allergy. The influence of Th17 lymphocytes in cancer remains however ambiguous. The plethoric functions of Th17 may rely on the remarkable plasticity of these cells, endowed with the ability to trans-differentiate into other Th subpopulations depending on the environmental cytokine context. The possibility to generate Th17 ex vivo has facilitated the elucidation of the signals and transcription factors required for their differentiation and functions and has allowed for the evaluation of their functions following adoptive transfer in vivo. Several protocols have been developed to produce Th17 in vitro. The intent of this chapter is to provide examples of procedures for generating and expanding Th17 ex vivo.

IL-17A-producing T cells and associated cytokines are involved in the progression of gastric cancer

Interleukin-17A-producing T cells (IL-17A+ T) (IL-17A+CD4+ Th17, IL-17A+CD8+ Tc17 and IL-17A+ γδT17 cells) and associated cytokines (IL-17A, IL-23 and IL-1β) play crucial roles in inflammation-associated diseases, such as infection, autoimmunity and tumors. Th17 cells promote human gastric cancer (GC), although the source of intracellular IL‑17A and the roles of Tc17 and γδT17 cells remain poorly understood. In this study, the frequencies of circulating Th17 and γδT17 cells in patients with GC were found to be significantly increased compared to those in healthy donors; however, Tc17 cells were decreased in these patients, and a negative relationship was found between the frequencies of Th17 and Tc17 cells. Moreover, the cytokine IL‑17A was found to be produced mainly by Th17 cells in human peripheral blood. Similarly, serum cytokine levels and relative mRNA expression levels of IL‑17A, IL‑23 and IL‑1β were significantly increased in patients with GC, and the frequency of Th17 cells was closely associated with serum IL‑17A concentrations in patients with GC. Additionally, Th17 cells and associated cytokines were present at significantly different levels during the progression and metastasis of GC, as were Tc17 and γδT17 cells. Taken together, these findings suggest that IL-17A+ T cells and associated cytokines might play crucial roles in human GC progression and metastasis and thus represent potential targets for treatment.

LAP TGF-Beta Subset of CD4(+)CD25(+)CD127(-) Treg Cells is Increased and Overexpresses LAP TGF-Beta in Lung Adenocarcinoma Patients

Lung cancer is the leading cause of cancer death worldwide. Adenocarcinoma, the most commonly diagnosed histologic type of lung cancer, is associated with smoking. Cigarette smoke promotes inflammation on the airways, which might be mediated by Th17 cells. This inflammatory environment may contribute to tumor development. In contrast, some reports indicate that tumors may induce immunosuppressive Treg cells to dampen immune reactivity, supporting tumor growth and progression. Thus, we aimed to analyze whether chronic inflammation or immunosuppression predominates at the systemic level in lung adenocarcinoma patients, and several cytokines and Th17 and Treg cells were studied. Higher proportions of IL-17-producing CD4⁺ T-cells were found in smoking control subjects and in lung adenocarcinoma patients compared to nonsmoking control subjects. In addition, lung adenocarcinoma patients increased both plasma concentrations of IL-2, IL-4, IL-6, and IL-10, and proportions of Latency Associated Peptide (LAP) TGF-β subset of CD4⁺CD25⁺CD127⁻ Treg cells, which overexpressed LAP TGF-β. This knowledge may lead to the development of immunotherapies that could inhibit the suppressor activity mediated by the LAP TGF-β subset of CD4⁺CD25⁺CD127⁻ Treg cells to promote reactivity of immune cells against lung adenocarcinoma cells.

Elevated Th22 as well as Th17 cells associated with therapeutic outcome and clinical stage are potential targets in patients with multiple myeloma

T helper (Th) cell imbalance plays important roles in tumor development and their effects in Multiple myeloma (MM) remain unclear. In the present study, we investigated the levels and clinical significance of Th22, Th17 and Th1 cells in patients with MM. Th subsets were examined by flow cytometry. Plasma IL-22, IL-17A and IFN-γ concentrations were measured by ELISA. AHR and RORC mRNA expression was examined by RT-PCR. Here, we found that the frequency of Th22 cells was significantly elevated in peripheral blood (PB) and bone marrow (BM) of newly-diagnosed MM patients, and recovered in complete remission patients after chemotherapy. The circulating Th17 cells accompanied by IL-17A levels were also up-regulated in MM patients and decreased after remission. We also found that there was a significantly positive correlation between Th22 and Th17 cells in MM patients. Moreover, the frequencies of Th22 and Th17 cells were higher in stage III than in stage I+II of MM. Our data demonstrated that Th22 and Th17 cells might be important therapeutic targets in multiple myeloma and could facilitate the effect of antitumor immunotherapy.

The role of regulatory T cells and microglia in glioblastoma-associated immunosuppression

Cell-mediated suppression of anti-tumor immunity is multifactorial in patients with cancer, and recent studies have focused on several distinct cellular agents that are associated with this phenomenon. This review will focus on the potential role of regulatory T cells (Tregs) and microglia in the suppression of cellular immunity observed in patients with glioblastoma. We discuss the ontogeny, basic biology, evidence for activity, and potential clinical options for targeting Tregs and microglia as part of immunotherapy in affected patients.

IL-12 and IL-23 cytokines: from discovery to targeted therapies for immune-mediated inflammatory diseases

The cytokine interleukin-12 (IL-12) was thought to have a central role in T cell-mediated responses in inflammation for more than a decade after it was first identified. Discovery of the cytokine IL-23, which shares a common p40 subunit with IL-12, prompted efforts to clarify the relative contribution of these two cytokines in immune regulation. Ustekinumab, a therapeutic agent targeting both cytokines, was recently approved to treat psoriasis and psoriatic arthritis, and related agents are in clinical testing for a variety of inflammatory disorders. Here we discuss the therapeutic rationale for targeting these cytokines, the unintended consequences for host defense and tumor surveillance and potential ways in which these therapies can be applied to treat additional immune disorders.

Reduced IL-17A Secretion Is Associated with High Levels of Pneumococcal Nasopharyngeal Carriage in Fijian Children

Streptococcus pneumonia (the pneumococcus) is the leading vaccine preventable cause of serious infections in infants under 5 years of age. The major correlate of protection for pneumococcal infections is serotype-specific IgG antibody. More recently, antibody-independent mechanisms of protection have also been identified. Preclinical studies have found that IL-17 secreting CD4+ Th17 cells in reducing pneumococcal colonisation. This study assessed IL-17A levels in children from Fiji with high and low pneumococcal carriage density, as measured by quantitative real-time PCR (qPCR). We studied Th17 responses in 54 children who were designated as high density carriers (N=27, >8.21x10⁵ CFU/ml) or low density carriers (N=27, <1.67x10⁵ CFU/ml). Blood samples were collected, and isolated peripheral blood mononuclear cells (PBMCs) were stimulated for 6 days. Supernatants were harvested for cytokine analysis by multiplex bead array and/or ELISA. Th17 cytokines assayed included IL-17A, IL-21, IL-22 as well as TNF-α, IL-10, TGF-β, IL-6, IL-23 and IFNγ. Cytokine levels were significantly lower in children with high density pneumococcal carriage compared with children with low density carriage for IL-17A (p=0.002) and IL-23 (p=0.04). There was a trend towards significance for IL-22 (p=0.057) while no difference was observed for the other cytokines. These data provide further support for the role of Th17-mediated protection in humans and suggest that these cytokines may be important in the defence against pneumococcal carriage.

The alteration and clinical significance of Th22/Th17/Th1 cells in patients with chronic myeloid leukemia

T helper- (Th-) cell immunodeficiency plays important roles in tumor development and their effects in chronic myeloid leukemia (CML) remain unclear. In the present study, we mainly investigated the role of Th22, Th17, and Th1 cell and their related cytokines (IL-22, IL-17, and IFN-r) in the pathophysiology of CML. Bone marrow (BM) and peripheral blood (PB) were extracted from newly diagnosed (ND), chronic phase- (CP-) CML patients, and controls. Th subsets were examined by flow cytometry. Plasma IL-22, IL-17, and IFN-r concentrations were measured by ELISA. AHR and RORC mRNA expressions were examined by RT-PCR. The frequencies of Th22, Th17, and Th1 cells, along with the expression of specific transcription factors RORC and AHR, were significantly decreased in ND patients compared with healthy controls, while all these abnormality recovered in CP patients. In addition, there existed a significantly positive relationship between Th22 and Th17 cells in PB or BM. A significantly negative relationship was found between Th cells (Th22, Th17, or Th1) and BCR-ABL (%) IS or the number of PB white blood cells. All these results demonstrated that Th22, Th17, and Th1 cells might be important therapeutic targets in CML and could facilitate a better outcome for tumor immunotherapy.

A stressful microenvironment: opposing effects of the endoplasmic reticulum stress response in the suppression and enhancement of adaptive tumor immunity

The recent clinical success of immunotherapy in the treatment of certain types of cancer has demonstrated the powerful ability of the immune system to control tumor growth, leading to significantly improved patient survival. However, despite these promising results current immunotherapeutic strategies are still limited and have not yet achieved broad acceptance outside the context of metastatic melanoma. The limitations of current immunotherapeutic approaches can be attributed in part to suppressive mechanisms present in the tumor microenvironment that hamper the generation of robust antitumor immune responses thus allowing tumor cells to escape immune-mediated destruction. The endoplasmic reticulum (ER) stress response has recently emerged as a potent regulator of tumor immunity. The ER stress response is an adaptive mechanism that allows tumor cells to survive in the harsh growth conditions inherent to the tumor milieu such as low oxygen (hypoxia), low pH and low levels of glucose. Activation of ER stress can also alter the cancer cell response to therapies. In addition, the ER stress response promotes tumor immune evasion by inducing the production of protumorigenic inflammatory cytokines and impairing tumor antigen presentation. However, the ER stress response can boost antitumor immunity in some situations by enhancing the processing and presentation of tumor antigens and by inducing the release of immunogenic factors from stressed tumor cells. Here, we discuss the dualistic role of the ER stress response in the modulation of tumor immunity and highlight how strategies to either induce or block ER stress can be employed to improve the clinical efficacy of tumor immunotherapy.

Tertiary Lymphoid Structure-Associated B Cells are Key Players in Anti-Tumor Immunity

It is now admitted that the immune system plays a major role in tumor control. Besides the existence of tumor-specific T cells and B cells, many studies have demonstrated that high numbers of tumor-infiltrating lymphocytes are associated with good clinical outcome. In addition, not only the density but also the organization of tumor-infiltrating immune cells has been shown to determine patient survival. Indeed, more and more studies describe the development within the tumor microenvironment of tertiary lymphoid structures (TLS), whose presence has a positive impact on tumor prognosis. TLS are transient ectopic lymphoid aggregates displaying the same organization and functionality as canonical secondary lymphoid organs, with T-cell-rich and B-cell-rich areas that are sites for the differentiation of effector and memory T cells and B cells. However, factors favoring the emergence of such structures within tumors still need to be fully characterized. In this review, we survey the state of the art of what is known about the general organization, induction, and functionality of TLS during chronic inflammation, and more especially in cancer, with a particular focus on the B-cell compartment. We detail the role played by TLS B cells in anti-tumor immunity, both as antigen-presenting cells and tumor antigen-specific antibody-secreting cells, and raise the question of the capacity of chemotherapeutic and immunotherapeutic agents to induce the development of TLS within tumors. Finally, we explore how to take advantage of our knowledge on TLS B cells to develop new therapeutic tools.