Decreased expression of interleukin-36α correlates with poor prognosis in hepatocellular carcinoma

Interleukin-36α (IL-36α) has been found to have a prominent role in the pathogenesis of inflammatory disorders; however, little is known about the role of IL-36α in cancer. In this study, we investigated the expression, prognostic value, and the underlying antitumor mechanism of IL-36α in hepatocellular carcinoma (HCC). From immunohistochemistry analysis, IL-36α expression was lower in poorly differentiated HCC cells. In clinicopathological analysis, low IL-36α expression significantly correlated with tumor size, histological differentiation, tumor stage, and vascular invasion, and low intratumoral IL-36α expression had significantly worse overall survival rates and shorter disease-free survival rates. Moreover, intratumoral IL-36α expression was an independent risk factor for overall survival. Consecutive sections were used to detect CD3⁺, CD8⁺, and CD4⁺ tumor-infiltrating lymphocytes (TILs), and we found that high-IL-36α-expressing tumor tissues exhibited a significantly higher proportion of intratumoral CD3⁺ and CD8⁺ TILs, but not CD4⁺ TILs. Our in vitro model confirmed that supernatant from IL-36α-overexpressing human HCC cells had an increased capacity to recruit CD3⁺ and CD8⁺ T cells. Consistently, mouse HCC cells engineered to overexpress IL-36α demonstrated markedly delayed growth in vivo, as well as higher levels of intratumoral CD3⁺ and CD8⁺ TILs, compared with control mice. In vitro chemotaxis analysis also showed that mouse HCC cells overexpressing IL-36α could recruit more number of CD3⁺ and CD8⁺ T cells. These results show that IL-36α expression may play a pivotal role in determining the prognosis of patients with HCC, which we attribute to the activation of adaptive T cell immunity, especially CD8⁺ T cell immune response.     

Modulation by IL-2 of CD70 and CD27 expression on CD8+ T cells: importance for the therapeutic effectiveness of cell transfer immunotherapy

Proper T cell function relies on the integration of signals delivered by Ag, cytokine, and costimulatory receptors. In this study, the interactions between IL-2, CD27, and its ligand CD70 and their effects on human T cell function were examined. Unstimulated CD8(+) T cells expressed relatively low levels of CD70 and high levels of CD27. Incubation in vitro with high doses of IL-2 (3,000 IU/ml) or administration of IL-2 in vivo resulted in substantial up-regulation of CD70 expression and the concomitant loss of cell surface CD27 expression on CD8(+) cells. Withdrawal of IL-2 from activated CD8(+) T cells that had been maintained in IL-2 resulted in a reversal of the expression of these two markers, whereas reciprocal changes were seen following treatment of PBMCs with IL-2. The proliferation observed in cells stimulated with IL-2 primarily occurred in a subset of the CD70(+)CD8(+) T cells that up-regulated IL-2 receptor expression but did not occur in CD70(-)CD8(+) T cells. Blocking CD70 resulted in a significant reduction of T cell proliferation induced by high-dose IL-2, indicating that the interaction of CD70 with CD27 played a direct role in T cell activation mediated by IL-2. Finally, studies conducted on tumor-infiltrating lymphocyte (TIL) samples that were administered to melanoma patients indicated that the size of the pool of CD27(+)CD8(+) T cells in bulk TILs was highly associated (p = 0.004) with the ability of these TILs to mediate tumor regression following adoptive transfer.     

Analysis of CD137L and IL-17 Expression in Tumor Tissue as Prognostic Indicators for Gliblastoma

Glioblastoma multiforme (GBM) is the most common form of malignant glioma, characterized by genetic instability and unpredictable clinical behavior. GBM is marked by an extremely poor prognosis with median overall survival of 12~14 months. In this study, we detected the CD137L-expressing cells and IL-17-expressing cells in tumor tissues resected from patients with GBM. Expression of CD137L and IL-17 were assessed by immunohistochemistry, and the prognostic value of CD137L and IL-17 expression within the tumor tissues were assessed by Cox regression and Kaplan-Meier analysis. Immunohistochemical detection showed that positive cells of CD137L and IL-17 in glioblastoma tissue samples were 46.3% (19/ 41) and 73.2% (30/41) respectively. Expression of CD137L was not correlated with overall survival of GBM patients (P=0.594), while significantly longer survival rate was seen in patients with high expression of IL-17, compared to those with low expression of IL-17 (P=0.007). In addition, we also found that IL-17 expression was significantly correlated with Progression-free survival (PFS) (P=0.016) and death rate (P=0.01). Furthermore, multivariate Cox proportional hazard analyses revealed that IL-17 (P=0.018) and PFS (P=0.028) were independent factors affecting the overall survival probability. Kaplan-Meier analysis showed that PFS of high expression of IL-17 group were significantly longer (P=0.004) than low expression group with GBM. It is concluded that high levels of IL-17 expression in the tumor tissues may be a good prognostic marker for patients with GBM.     

Tumor-infiltrating lymphocytes predict response to chemotherapy in patients with advance non-small cell lung cancer

Accumulating preclinical evidence suggests that anticancer immune responses contribute to the success of chemotherapy. The predictive significance of tumor-infiltrating lymphocytes (TILs) for response to neoadjuvant chemotherapy in non-small cell lung cancer (NSCLC) remains unknown. The aim of this study was to investigate the prognostic and predictive value of TIL subtypes in patients with advanced NSCLC treated with platinum-based chemotherapy. In total, 159 patients with stage III and IV NSCLC were retrospectively enrolled. The prevalence of CD3(+), CD4(+), CD8(+) and Foxp3(+) TILs was assessed by immunohistochemistry in tumor tissue obtained before chemotherapy. The density of TILs subgroups was treated as dichotomous variables using the median values as cutoff. Survival curves were estimated by the Kaplan-Meier method, and differences in overall survival between groups were determined using the Log-rank test. Prognostic effects of TIL subsets density were evaluated by Cox regression analysis. The presence of CD3(+), CD4(+), CD8(+), and FOXP3(+) TILs was not correlated with any clinicopathological features. Neither the prevalence of TILs nor combined analysis displayed obvious prognostic performances for overall survival in Cox regression model. Instead, higher FOXP3(+)/CD8(+) ratio in tumor sites was an independent factor for poor response to platinum-based chemotherapy in overall cohort. These findings suggest that immunological CD8(+) and FOXP3(+)Tregs cell infiltrate within tumor environment is predictive of response to platinum-based neoadjuvant chemotherapy in advanced NSCLC patients. The understanding of the clinical relevance of the microenvironmental immunological milieu might provide an important clue for the design of novel strategies in cancer immunotherapy.     

Accumulation of CD45RO<Superscript>+</Superscript> cells in peritoneal carcinomatous fluid favours survival of ovarian carcinoma patients

In 44 patients with advanced ovarian carcinoma (OC) a fraction of CD45RO(+) lymphocytes in the blood and peritoneal carcinomatous fluid (PCF) was investigated. Thirty-one patients received cisplatinum with cyclophosphamide +/- doxorubicin. This group was followed from 2.2 to 9 years (mean: 45 months). In 23 out of 31 patients, the percentage of CD45RO(+) lymphocytes was higher in the PCF than in the blood samples. Patients with these higher lymphocyte levels experienced longer survival than those who did not show any excess of CD45RO(+) lymphocytes in PCF ( P=0.02). This was further verified by the use multivariate Cox analysis which included an assessment of the percentage of CD45RO(+) lymphocytes in PCF, age, FIGO status, histology, treatment (CAP or CP) and residual disease (RD) post-surgery. This analysis revealed that two factors had an independent power of prediction: RD ( P=0.02) and the percentage of CD45RO(+) cells in PCF ( P=0.04). Therefore, CD45RO(+) lymphocytes were studied in further detail in a group of 20 patients. This study revealed that PCF CD45RO(+) lymphocytes were characterized by: (1) a higher proportion of cells co-expressing activation markers (HLA-DR, CD28) and higher levels of mRNA for CXC chemokines (IP-10, IL-8) and for IL-10, but with lower levels for IL-2; (2) higher levels of Ki67, bcl-2 and p53 mRNA as compared to those in blood. In conclusion, in the present study it was found that an accumulation of activated CD45RO(+) cells in PCF had a beneficial effect on the survival of patients receiving platinum-based chemotherapy.     

Expression of MG7-Ag in patients with gastric cancer correlates with weaker T cell immune response and more proinflammatory cytokine secretion.

MG7-Ag is a human gastric-carcinoma-associated antigen with a high specificity. So far it is remained unclear whether MG7-Ag is correlated with the in vivo cellular immune response of patients with gastric cancer. In this study, we detected the expression of the T cell receptor (TCR) repertoire of T cell subpopulations and cytokines in tumor-infiltrating lymphocytes (TIL), peripheral blood lymphocytes (PBL), and residue benign mucosal lymphocytes (NML) of patients with gastric cancer using semiquantitative RT-PCR. Our data showed that the expanded clones in CD8(+) NML and TIL and CD4+ NML and PBL in MG7-Ag-positive patients were significantly fewer than those of MG7-Ag-negative patients (p = 0.0360; p = 0.0026; p = 0.0065 p = 0.0109, respectively). The levels of IL-8 in CD8(+) TIL and TNF in CD4(+) TIL from the MG7-Ag-positive group were significantly higher than those from the MG7-Ag-negative group (p = 0.0302; p = 0.0177, respectively). Taken together, the results demonstrated a weaker T cell immune response and more proinflammatory cytokine secretion in MG7-Ag-positive patients with gastric cancer than in MG7-Ag-negative ones. This likely contributes to the poor prognosis in MG7-Ag-positive gastric-cancer patients.     

Tumor Microenvironment Macrophage Inhibitory Factor Directs the Accumulation of Interleukin-17-producing Tumor-infiltrating Lymphocytes and Predicts Favorable Survival in Nasopharyngeal Carcinoma Patients

The accumulation of an intratumoral CD4⁺ interleukin-17-producing subset (Th17) of tumor-infiltrating lymphocytes (TILs) is a general characteristic in many cancers. The relationship between the percentage of Th17 cells and clinical prognosis differs among cancers. The mechanism responsible for the increasing percentage of such cells in NPC is still unknown, as is their biological function. Here, our data showed an increase of Th17 cells in tumor tissues relative to their numbers in normal nasopharynx tissues or in the matched peripheral blood of NPC patients. Th17 cells in tumor tissue produced more IFNγ than did those in the peripheral blood of matched NPC patients and healthy controls. We observed high levels of CD154, G-CSF, CXCL1, IL-6, IL-8, and macrophage inhibitory factor (MIF) out of 36 cytokines examined in tumor tissue cultures. MIF promoted the generation and recruitment of Th17 cells mediated by NPC tumor cells in vitro; this promoting effect was mainly dependent on the mammalian target of rapamycin pathway and was mediated by the MIF-CXCR4 axis. Finally, the expression level of MIF in tumor cells and in TILs was positively correlated in NPC tumor tissues, and the frequency of MIF-positive TILs was positively correlated with NPC patient clinical outcomes. Taken together, our findings illustrate that tumor-derived MIF can affect patient prognosis, which might be related to the increase of Th17 cells in the NPC tumor microenvironment.     

The accumulation and prognosis value of tumor infiltrating IL-17 producing cells in esophageal squamous cell carcinoma

Background

The role of IL-17 producing cells in tumors is controversial. In the present study, we investigated the prognostic value of measuring tumor-infiltrating IL-17 producing cell levels in human esophageal squamous cell carcinoma (ESCC).

Methodology/Principal Findings

Immunohistochemical staining was performed to investigate the levels of IL-17+ tumor infiltrating lymphocytes (TILs), as well as CD8+ cytotoxic T lymphocytes (CTLs) and CD57+ natural killer (NK) cells from 181 ESCC patients. The prognostic value of measuring the densities of IL-17+TILs and the correlation with CTLs and NK was evaluated. IL-17 producing cells were detected in esophageal squamous cell carcinoma tissues. The IL-17 producing cells were major CD4 positive, but Foxp3 negative. The median level of IL-17+TILs was 3.90 cells/high power microscopic field (HPF). The density of IL-17 producing cells correlated negatively with T stage (P = 0.042). The higher densities of tumor infiltrating IL-17+ lymphocytes were associated with better overall survival (P = 0.031). Furthermore, we found that there were positive correlations between levels of IL-17 producing cells and the densities of CD8+cells, as well as CD57+cells (r = 0.198, P = 0.008 for CD8+ cells and r = 0.261, P<0.001 for CD57+ cells, respectively). The prognosis analysis also showed that the higher levels of CD8+ CTLs and CD57+ NK cells correlated with better overall survival of ESCC patients.

Conclusions

Our study suggests that tumor infiltrating IL-17 producing cells in ESCC patients may have protective roles in the tumor microenvironment and may be treated as a prognostic marker for ESCC patients.     

Upregulated Expression of C-X-C Chemokine Receptor 4 Is an Independent Prognostic Predictor for Patients with Gastric Cancer

Aberrant chemokine (C-X-C motif) receptor CXCR4 expressions in malignant tissues have been reported, but its role in gastric cancer prognosis remains unknown. Our studies were designed to investigate the expression and prognostic significance of CXCR4 in patients with gastric cancer. CXCR4 expression was retrospectively analyzed by immunohistochemistry in 97 patients with gastric adenocarcinoma from China. Results were assessed for association with clinical features and overall survival by using Kaplan-Meier analysis. Prognostic values of CXCR4 expression and clinical outcomes were evaluated by Cox regression analysis. A molecular prognostic stratification scheme incorporating CXCR4 expression was determined by using receiver operating characteristic (ROC) analysis. The results show that CXCR4 predominantly localized in the cell membranes and cytoplasm. The protein level of CXCR4 was upregulation in gastric cancer tissues and upregulated expression of CXCR4 was only significantly associated with Lauren classification (P<0.001). Increased CXCR4 expression in gastric cancer tissues was positively correlated with poor overall survival of gastric cancer patients (P<0.001). Further multivariate Cox regression analysis suggested that intratumoral CXCR4 expression was an independent prognostic indicator for the disease. Applying the prognostic value of intratumoral CXCR4 density to TNM stage system showed a better prognostic value in patients with gastric cancer. In conclusion, intratumoral CXCR4 expression was recognized as an independent prognostic marker for the overall survival of patients with gastric cancer. On the basis of TNM stage, detection of CXCR4 expression will be helpful for predicting prognosis for patients with gastric cancer.     

TH(1)- and TH(2)-TYPE cytokine expression by activated t lymphocytes from the lung and spleen during the inflammatory response to respiratory syncytial virus

RSV is an important cause of lower respiratory tract illness in infants and the elderly worldwide. The components involved in immunity and those that contribute to inflammation of RSV-induced disease are not clearly understood. To address the relationship between activation antigen and cytokine expression, intracellular levels of IL-2, IL-4, IL-5 and IFN-gamma were determined for CD3, CD44, CD49d, CD54, CD62L and CD102 lymphocytes from the bronchoalveolar lavage and spleen. To examine activation at the DNA level, lymphocytes expressing IL-2, IL-4, IL-5 or IFN-gamma were analysed for G2+M DNA content or phosphatidylserine expression (apoptosis). Trafficking of lymphocytes to the BAL was detected at day 5 p.i., peaked day 7 p.i., and predominately involved CD54(+)and CD102(+)lymphocytes expressing high levels of IL-2, IL-4, IL-5 and IFN-gamma. Lymphocytes expressing CD44(+), CD49d(+)and CD62L(lo)were also observed, however they expressed these cytokines to a lesser extent. DNA analysis of lymphocytes expressing IL-2 or IFN-gamma revealed higher G2'M levels compared to lymphocytes expressing IL-4 or IL-5, suggesting greater activation of Th(1)-type lymphocytes in the lung. These data demonstrate that RSV-induced pulmonary inflammation involves extensive cellular activation and cytokine expression, particularly by CD54(+)and CD102(+)lymphocytes in the lung.     

Clinicopathologic roles of tumor-infiltrating lymphocytes and CD8-positive lymphocytes in lung cancer imprint smears in squamous cell carcinoma and adenocarcinoma

OBJECTIVE: To investigate the presence of tumor-infiltrating lymphocytes (TILs) and CD8-positive lymphocytes (CD8s) in lung cancers and to examine the prognostic significance of their relationship with clinicopathologic parameters. STUDY DESIGN: Primary tumor imprint smears from 83 lung cancers were consecutively obtained at surgery at Tsuchiura Kyodo General Hospital between 1996 and 1998. TILs were observed in Papanicolaou-stained smears, and CD8s were immunocytochemically visualized. RESULTS: TILs were judged positive in 42 cases (51%), and 34 of 83 cases (41%) were positive for CD8s. There was no correlation between the frequency of TILs and CD8s. TILs assessed by Papanicolaou staining in 83 cases showed no correlation with any clinicopathologic factors. CD8s were observed more frequently in squamous cell carcinomas (SCCs) than other adenocarcinomas. A high frequency of CD8s was associated with lymph node metastasis (p = 0.043), stage (p = 0.025) and tumor differentiation (p = 0.03). TILs and CD8s made no significant difference in survival. However, in SCC the patients positive for TILs but negative for CD8s survived and had a significantly better prognosis than did the others (p = 0.037). CONCLUSION: CD8s were associated with tumor progression and development of malignancy in lung cancers. Especially in SCC, the cases had a high frequency of TILs. A low number of CD8s may correlate with a favorable prognosis.     

Intratumor IL-17-Positive Mast Cells Are the Major Source of the IL-17 That Is Predictive of Survival in Gastric Cancer Patients

Interleukin-17 (IL-17) is prevalent in tumor tissue and suppresses effective anti-tumor immune responses. However, the source of the increased tumor-infiltrating IL-17 and its contribution to tumor progression in human gastric cancer remain poorly understood. In this study, we enrolled 112 gastric cancer patients, immunofluorescence was used to evaluate the colocalization of CD3, CD4, CD56, CD20, CD68, and mast cell tryptase (MCT) with IL-17. Immunohistochemistry was used to evaluate the distribution of microvessel density (CD34), CD66b⁺, CD68⁺, and FoxP3⁺ cells in different microanatomical areas. Prognostic value was determined by Kaplan-Meier analysis and a Cox regression model. The results showed that mast cells, but not T cells or macrophages, were the predominant cell type producing IL-17 in gastric cancer. Significant positive correlations were detected between densities of mast cell-derived IL-17 and microvessels, neutrophils, and regulatory T cells (Tregs). Futhermore, we found that the majority of vascular endothelial cells expressing Interleukin-17 receptor (IL-17R). Kaplan-Meier analysis revealed that increasing intratumor infiltrated mast cells and IL-17⁺ cells, as well as MCT⁺ IL-17⁺ cells, were significantly associated with worse overall survival. These findings indicated that mast cells were the major source of IL-17 in gastric cancer, and intratumor IL-17 infiltration may have promoted tumor progression by enhancing angiogenesis in the tumor microenvironment through the axis of IL-17/IL-17R. IL-17-positive mast cells showed a prognostic factor in gastric cancer, indicating that immunotherapy targeting mast cells might be an effective strategy to control intratumor IL-17 infiltration, and consequently reverse immunosuppression in the tumor microenvironment, facilitating cancer immunotherapy.     

High DGK-α and disabled MAPK pathways cause dysfunction of human tumor-infiltrating CD8+ T cells that is reversible by pharmacologic intervention

CD8(+) tumor-infiltrating T cells (CD8-TILs) are found in many types of tumors including human renal cell carcinoma. However, tumor rejection rarely occurs, suggesting limited functional activity in the tumor microenvironment. In this study, we document that CD8-TILs are unresponsive to CD3 stimulation, showing neither lytic activity, nor lytic granule exocytosis, nor IFN-γ production. Mechanistically, no deficits in TCR proximal signaling molecules (lymphocyte-specific protein tyrosine kinase, phospholipase Cγ) were identified. In contrast, distal TCR signaling was suppressed, as T cells of TILs showed strongly reduced steady-state phosphorylation of the MAPK ERK and were unable to increase phosphorylation of ERK and JNK as well as AKT and AKT client proteins (IκB, GSK3) after stimulation. These deficits were tumor-specific as they were not observed in CD8(+) T cells infiltrating non-tumor kidney areas (CD8(+) non-tumor kidney-infiltrating lymphocytes; CD8-NILs). Diacylglycerol kinase-α (DGK-α) was more highly expressed in CD8-TILs compared with that in CD8-NILs, and its inhibition improved ERK phosphorylation and lytic granule exocytosis. Cultivation of TILs in low-dose IL-2 reduced DGK-α protein levels, increased steady-state phosphorylation of ERK, improved stimulation-induced phosphorylation of ERK and AKT, and allowed more CD8-TILs to degranulate and to produce IFN-γ. Additionally, the protein level of the AKT client molecule p27kip, an inhibitory cell cycle protein, was reduced, whereas cyclin E, which promotes G1-S phase transition, was increased. These results indicate that the tumor-inflicted deficits of TILs are reversible. DGK-α inhibition and provision of IL-2 signals could be strategies to recruit the natural CD8(+) T cells to the anti-tumor response and may help prevent inactivation of adoptively transferred T cells thereby improving therapeutic efficacy.     

CD8+ tumor-infiltrating lymphocytes predict favorable prognosis in malignant pleural mesothelioma after resection

Defects in human leukocyte antigen (HLA) class I expression may allow tumor cells to escape immune recognition. T cell infiltration is associated with a good prognosis in many cancers. However, the role of HLA class I expression and tumor-infiltrating lymphocytes (TILs) in malignant pleural mesothelioma (MPM) has not been fully analyzed. In the present study, we investigated the immune profiles and conducted outcome analyses of MPM patients. HLA class I expression and TILs (CD4⁺, CD8⁺, and NK cells) were detected by immunohistochemistry in a series of 44 MPM cases. To detect HLA class I expression, specimens were stained with the anti-pan HLA class I monoclonal antibody EMR8-5. The expression of HLA class I was positive in all patients. There was no case that showed negative HLA class I expression. The density of CD4⁺ and CD8⁺ TILs were strongly correlated (R = 0.76, p < 0.001). A high density of CD8⁺ TILs was a significantly better prognostic factor for the survival of patients with extrapleural pneumonectomy (p < 0.05). Multivariate analysis revealed that a high density of CD8⁺ TILs is an independent prognostic factor for patients who underwent extrapleural pneumonectomy. The presence of intratumoral CD8⁺ T cells was correlated with an improved clinical outcome, raising the possibility that CD8⁺ T cells might play a pivotal role in the antitumor immune response against MPMs. Thus, the stimulation of CD8⁺ lymphocytes might be an efficacious immunotherapy for MPM patients.     

The IL-7Rα pathway is quantitatively and functionally altered in CD8 T cells in multiple sclerosis

The IL-7Rα single nucleotide polymorphism rs6897932 is associated with an increased risk for multiple sclerosis (MS). IL-7Rα is a promising candidate to be involved in autoimmunity, because it regulates T cell homeostasis, proliferation, and antiapoptotic signaling. However, the exact underlying mechanisms in the pathogenesis of MS are poorly understood. We investigated whether CD4 and CD8 lymphocyte subsets differed in IL-7Rα expression and functionality in 78 MS patients compared with 59 healthy controls (HC). A significantly higher frequency of IL-7Rα(+) CD8 effector memory (CD8EM) was found in MS. Moreover, IL-7Rα membrane expression was significantly increased in MS in naive and memory CD8 (all p < 0.05) with a similar trend in CD8EM (p = 0.055). No correlation was found between the expression level or frequency of IL-7Rα(+)CD8(+) and rs6897932 risk allele carriership. Upon IL-7 stimulation, MS patients had stronger STAT5 activation in CD8EM compared with HC. IL-7 stimulation had a differential effect on both mRNA and protein expression of granzyme A and granzyme B between MS and HC. Stainings of different lesions in postmortem MS brain material showed expression of IL-7 and CD8(+)IL-7Rα(+) in preactive, but not in active, demyelinating MS lesions, indicating involvement of IL-7Rα(+) lymphocytes in lesion development. The intralesional production of IL-7 in combination with the lower threshold for IL-7-induced cytotoxicity in MS may enhance the pathogenicity of these CD8 T cells. This is of special interest in light of the established demyelinating and cytotoxic actions of granzyme A.     

Chronic immune therapy induces a progressive increase in intratumoral T suppressor activity and a concurrent loss of tumor-specific CD8+ T effectors in her-2/neu transgenic mice bearing advanced spontaneous tumors

A single intratumoral injection of IL-12 and GM-CSF-encapsulated microspheres induces the complete regression of advanced spontaneous tumors in her-2/neu transgenic mice. However, tumor regression in this model is transient and long-term cure is not achieved due to recurrence. Posttherapy molecular analysis of immune activation/suppression markers within the tumor microenvironment demonstrated a dramatic up-regulation of IFN-gamma and a concomitant down-regulation of Forkhead/winged-helix protein 3 (Foxp3), TGFbeta, and IL-10 expression. Therapy-induced reversion of immune suppression was transient since all three markers of suppression recovered rapidly and surpassed pretherapy levels by day 7 after treatment, resulting in tumor resurgence. Repeated treatment enhanced short-term tumor regression, but did not augment long-term survival. Serial long-term analysis demonstrated that although chronic stimulation enhanced the IFN-gamma response, this was countered by a parallel increase in Foxp3, TGFbeta, and IL-10 expression. Analysis of tumor-infiltrating T lymphocyte populations showed that the expression of Foxp3 and IL-10 was associated with CD4(+)CD25(+) T cells. Repeated treatment resulted in a progressive increase in tumor-infiltrating CD4(+)CD25(+)Foxp3(+) T suppressor cells establishing their role in long-term neutralization of antitumor activity. Analysis of tumor-infiltrating CD8(+) T cells demonstrated that although treatment enhanced IFN-gamma production, antitumor cytotoxicity was diminished. Monitoring of CD8(+) T cells that specifically recognized a dominant MHC class I her-2/neu peptide showed a dramatic increase in tetramer-specific CD8(+) T cells after the first treatment; however, continuous therapy resulted in the loss of this population. These results demonstrate that both enhanced suppressor activity and deletion of tumor-specific T cells are responsible for the progressive loss of efficacy that is associated with chronic immune therapy.     

STAT3 and NF-kappaB signal pathway is required for IL-23-mediated IL-17 production in spontaneous arthritis animal model IL-1 receptor antagonist-deficient mice

IL-23 is a heterodimeric cytokine composed of a p19 subunit and the p40 subunit of IL-12. IL-23 has proinflammatory activity, inducing IL-17 secretion from activated CD4(+) T cells and stimulating the proliferation of memory CD4(+) T cells. We investigated the pathogenic role of IL-23 in CD4(+) T cells in mice lacking the IL-1R antagonist (IL-1Ra(-/-)), an animal model of spontaneous arthritis. IL-23 was strongly expressed in the inflamed joints of IL-1Ra(-/-) mice. Recombinant adenovirus expressing mouse IL-23 (rAd/mIL-23) significantly accelerated this joint inflammation and joint destruction. IL-1beta further increased the production of IL-23, which induced IL-17 production and OX40 expression in splenic CD4(+) T cells of IL-1Ra(-/-) mice. Blocking IL-23 with anti-p19 Ab abolished the IL-17 production induced by IL-1 in splenocyte cultures. The process of IL-23-induced IL-17 production in CD4(+) T cells was mediated via the activation of Jak2, PI3K/Akt, STAT3, and NF-kappaB, whereas p38 MAPK and AP-1 did not participate in the process. Our data suggest that IL-23 is a link between IL-1 and IL-17. IL-23 seems to be a central proinflammatory cytokine in the pathogenesis of this IL-1Ra(-/-) model of spontaneous arthritis. Its intracellular signaling pathway could be useful therapeutic targets in the treatment of autoimmune arthritis.     

Expression of IL-17 in human memory CD45RO+ T lymphocytes and its regulation by protein kinase A pathway.

In the present study, the authors compared the interleukin 17 (IL-17 expression of human naive and phenotypically defined memory T cells as well as its regulation by cAMP pathway. Our data showed that IL-17 mRNA was highly expressed in memory human peripheral CD8(+)45RO+T cells and CD4(+)45RO+T cells when peripheral blood mononuclear cells were first stimulated with ionomycin/PMA. IL-17 expression in memory CD8(+)T cells required accessory signals since culture of ionomycin/PMA-activated CD8(+)45RO+T cells alone did not result to IL-17 expression. In contrast, memory CD4(+)T cell population seems to be more independent. IL-17 and interferon gamma(IFN-gamma) mRNA were both inhibited in the presence of PGE2 or the cAMP analogue (dibutyryl-cAMP), while the anti-inflammatory cytokine IL-10 was highly increased. In contrast, naive CD45RA+T cells were unable to express IL-17 whatever the culture conditions. Naive CD4(+)and CD8(+)T cells were sensitive to the PKA regulatory pathway since they represent a significant source of IL-10 when PBMC were first cultured with ionomycin/PMA in the presence of either PGE2 or db-cAMP. The authors showed that naive cells are highly dependent to their microenvironment, since culture of ionomycin/PMA-activated CD45RA+T cells alone did not result in detectable levels of cytokines even in the presence of PGE2. Results also showed that PGE2 induced quite the same levels of intracellular cAMP in naive and memory cells suggesting that these cell populations are equally sensitive to PGE2. However, we suggest that PGE2 may be more efficient in blocking both IL-17 and IFN-gamma expression in already primed memory T cells, rather than in suppressing naive T cells that could represent a significant source of IL-10. Data suggest that PKA activation pathway plays a critical role in the regulation of cytokine profiles and consequently the functional properties of both human naive and memory CD4(+) and CD8(+)T cells during the immune and inflammatory processes.