Renal cell carcinomas produce IL-6, IL-10, IL-11, and TGF-beta 1 in primary cultures and modulate T lymphocyte blast transformation

Blockade of IL-10 Signaling Ensures Mifamurtide Efficacy in Metastatic Osteosarcoma

Osteosarcoma (OS) is the most common primary malignancy of the bone, highly aggressive and metastasizing, and it mainly affects children and adolescents. The current standard of care for OS is a combination of surgery and chemotherapy. However, these treatment options are not always successful, especially in cases of metastatic or recurrent osteosarcomas. For this reason, research into new therapeutic strategies is currently underway, and immunotherapies have received considerable attention. Mifamurtide stands out among the most studied immunostimulant drugs; nevertheless, there are very conflicting opinions on its therapeutic efficacy. Here, we aimed to investigate mifamurtide efficacy through in vitro and in vivo experiments. Our results led us to identify a new possible target useful to improve mifamurtide effectiveness on metastatic OS: the cytokine interleukin-10 (IL-10). We provide experimental evidence that the synergic use of an anti-IL-10 antibody in combination with mifamurtide causes a significantly increased mortality rate in highest-grade OS cells and lower metastasis in an in vivo model compared with mifamurtide alone. Overall, our data suggest that mifamurtide in combination with an anti-IL-10 antibody could be proposed as a new treatment protocol to be studied to improve the outcomes of OS patients.

What Mediates Fibrosis in the Tumor Microenvironment of Clear Renal Cell Carcinoma

Previous studies have demonstrated that direct targeting of interstitial cancer-associated fibroblasts (CAF) and tumor fibrosis alone seemed to be an unpromising treatment option for malignant tumors. Therefore, it is necessary to further explore the mechanism of the influence of collagen and tumor fibrosis on the biological behavior of malignant tumors. The current study aimed to explore the effect of intratumor fibrosis on the prognosis of renal clear cell carcinoma (ccRCC) and its mechanism. With the bioinformatic analysis of The Cancer Genome Atlas (TCGA) database (n = 537), the study showed that high Collagen type I α 1 (COL1A1) mRNA expression indicated the poor prognosis of ccRCC patients compared with low expression ones. We further used the Two-photon-excited fluorescence (TPEF)/second harmonic generation (SHG) microscopy to determine the intratumor fibrosis of 68 patients with surgical resection of ccRCC and confirmed that a high fibrosis level in the tumor was associated with a poor prognosis compared with patients with low expression (Progression-Free Survival: p = 0.030). We further measured the protein chips of 640 cytokines in ccRCC specimens and found that several cytokines, including prolactin (PRL), were associated with the degree of fibrosis in the tumor, as confirmed by the prolactin receptor (PRLR) immunohistochemical method. In addition, the study showed that PRLR expression decreased significantly in the ccRCC compared with adjacent normal tissue (p < 0.05). Our research shows that low expression of PRLR predicted the poor survival of the patient. We used the Cell Counting Kit-8 experiment, the transwell and the plate clone formation assay to evaluate the role of PRL in the 7860 and the ACHN cell lines. We found that PRL promoted ccRCC cell proliferation and migration. JAK-STAT3 activation was found in the high prolactin expression group by mass spectrum analysis. This study delineated the fibrosis-based tumor microenvironment characteristics of ccRCC. PRL/PRLR may be involved in the fibrosis process and are essential prognostic risk factors for ccRCC.

TGF-β and microRNA Interplay in Genitourinary Cancers

Genitourinary cancers (GCs) include a large group of different types of tumors localizing to the kidney, bladder, prostate, testis, and penis. Despite highly divergent molecular patterns, most GCs share commonly disturbed signaling pathways that involve the activity of TGF-β (transforming growth factor beta). TGF-β is a pleiotropic cytokine that regulates key cancer-related molecular and cellular processes, including proliferation, migration, invasion, apoptosis, and chemoresistance. The understanding of the mechanisms of TGF-β actions in cancer is hindered by the "TGF-β paradox" in which early stages of cancerogenic process are suppressed by TGF-β while advanced stages are stimulated by its activity. A growing body of evidence suggests that these paradoxical TGF-β actions could result from the interplay with microRNAs: Short, non-coding RNAs that regulate gene expression by binding to target transcripts and inducing mRNA degradation or inhibition of translation. Here, we discuss the current knowledge of TGF-β signaling in GCs. Importantly, TGF-β signaling and microRNA-mediated regulation of gene expression often act in complicated feedback circuits that involve other crucial regulators of cancer progression (e.g., androgen receptor). Furthermore, recently published in vitro and in vivo studies clearly indicate that the interplay between microRNAs and the TGF-β signaling pathway offers new potential treatment options for GC patients.

KRT8 upregulation promotes tumor metastasis and is predictive of a poor prognosis in clear cell renal cell carcinoma

Keratin 8 (KRT8) plays an essential role in the development and metastasis of multiple human cancers. However, its role in clear cell renal cell carcinoma (ccRCC) remains unexplored. Here, we investigated the expression pattern, clinical significance, and function of KRT8 in ccRCC. KRT8 mRNA and protein levels were determined in two large cohorts using quantitative real-time polymerase chain reaction (qRT-PCR) and tissue microarray (TMA) immunohistochemistry (IHC), respectively. We found that KRT8 expression was upregulated in ccRCC and vein tumor thrombi (VTTs). KRT8 overexpression in ccRCC was significantly correlated with aggressive characteristics and was predictive of a poor prognosis in ccRCC patients. Moreover, KRT8 overexpression in renal cancer cell lines promoted cell migration and invasion. In contrast, KRT8 knockdown suppressed ccRCC metastasis both in vitro and in vivo. In addition, our findings showed that KRT8 promoted ccRCC metastasis by increasing IL-11 expression, causing IL-11 autocrine induction, and triggering STAT3 signaling. Overall, this study established the significance of KRT8-IL-11 axis activation in aggressive ccRCC and defined a novel critical signaling mechanism that drives human ccRCC invasion and metastasis.

Comparative Gene Expression Profiling of Primary and Metastatic Renal Cell Carcinoma Stem Cell-Like Cancer Cells

Background

Recent advancement in cancer research has shown that tumors are highly heterogeneous, and multiple phenotypically different cell populations are found in a single tumor. Cancer development and tumor growth are driven by specific types of cells—stem cell-like cancer cells (SCLCCs)—which are also responsible for metastatic spread and drug resistance. This research was designed to verify the presence of SCLCCs in renal cell cancer cell lines. Subsequently, we aimed to characterize phenotype and cell biology of CD105+ cells, defined previously as renal cell carcinoma tumor-initiating cells. The main goal of the project was to describe the gene-expression profile of stem cell-like cancer cells of primary tumor and metastatic origin.

Materials and Methods

Real-time PCR analysis of stemness genes (Oct-4, Nanog and Ncam) and soft agar colony formation assay were conducted to check the stemness properties of renal cell carcinoma (RCC) cell lines. FACS analysis of CD105+ and CD133+ cells was performed on RCC cells. Isolated CD105+ cells were verified for expression of mesenchymal markers—CD24, CD146, CD90, CD73, CD44, CD11b, CD19, CD34, CD45, HLA-DR and alkaline phosphatase. Hanging drop assay was used to investigate CD105+ cell-cell cohesion. Analysis of free-floating 3D spheres formed by isolated CD105+ was verified, as spheres have been hypothesized to contain undifferentiated multipotent progenitor cells. Finally, CD105+ cells were sorted from primary (Caki-2) and metastatic (ACHN) renal cell cancer cell lines. Gene-expression profiling of sorted CD105+ cells was performed with Agilent’s human GE 4x44K v2 microarrays. Differentially expressed genes were further categorized into canonical pathways. Network analysis and downstream analysis were performed with Ingenuity Pathway Analysis.

Results

Metastatic RCC cell lines (ACHN and Caki-1) demonstrated higher colony-forming ability in comparison to primary RCC cell lines. Metastatic RCC cell lines harbor numerous CD105+ cell subpopulations and have higher expression of stemness genes (Oct-4 and Nanog). CD105+ cells adopt 3D grape-like floating structures under handing drop conditions. Sorted CD105+ cells are positive for human mesenchymal stem cell (MSC) markers CD90, CD73, CD44, CD146, and alkaline phosphatase activity, but not for CD24 and hematopoietic lineage markers CD34, CD11b, CD19, CD45, and HLA-DR. 1411 genes are commonly differentially expressed in CD105+ cells (both from primary [Caki-2] and metastatic RCC [ACHN] cells) in comparison to a healthy kidney epithelial cell line (ASE-5063). TGF-β, Wnt/β-catenine, epithelial-mesenchymal transition (EMT), Rap1 signaling, PI3K-Akt signaling, and Hippo signaling pathway are deregulated in CD105+ cells. TGFB1, ERBB2, and TNF are the most significant transcriptional regulators activated in these cells.

Conclusions

All together, RCC-CD105+ cells present stemlike properties. These stem cell-like cancer cells may represent a novel target for therapy. A unique gene-expression profile of CD105+ cells could be used as initial data for subsequent functional studies and drug design.

Interleukin-6, Interleukin-10 and Heat Shock Protein-90 Expression in Renal Epithelial Neoplasias and Surrounding Normal-Appearing Renal Parenchyma

Cytokines, notably the interleukins IL-6 and IL-10, have an important role in the development and progression of renal-cell carcinomas, acting in the host-tumor interaction and in tumor bulk. Heat shock proteins (HSP), in particular HSP-90, may have a regulatory role in cytokine biosynthesis and prognostic implication in some tumors. To define the roles of the cytokines IL-6 and IL-10 and HSP-90 in the progression of renal-cell carcinoma we analyzed immunohistochemical expression of these proteins in human renal-cell carcinomas from 95 total nephrectomies. IL-6, IL-10 and HSP-90 proteins were more strongly expressed in epithelium and stroma of the renal tumoral compartment than in adjacent normal peritumoral tissue. But the difference reached significance only for HSP-90 protein. The percentage of cells expressing IL-6, IL-10 and HSP-90 immunoreactivity was higher in benign epithelial tumors, than in normal peritumoral tissue, but lower than in renal-cell carcinomas. Whereas HSP-90 immunoreactivity seemed higher in more aggressive histological phenotypes (collecting-duct carcinoma) of renal-cell carcinomas, IL-10 protein levels were higher in more advanced TNM stage (pT3) tumors. Our observation suggests that IL-6 and IL-10 and HSP-90 may be useful markers associated with the development and progression of renal-cell carcinomas and have independent functional roles in this malignant condition.

IL-11 signaling as a therapeutic target for cancer

IL-11 is a member of the IL-6 family of cytokines. While it was discovered over 20 years ago, we have very little understanding of the role of IL-11 during normal homeostasis and disease. Recently, IL-11 has gained interest for its newly recognized role in the pathogenesis of diseases that are attributed to deregulated mucosal homeostasis, including gastrointestinal cancers. IL-11 can increase the tumorigenic capacity of cells, including survival of the cell or origin, proliferation of cancerous cells and survival of metastatic cells at distant organs. Here we outline our current understanding of IL-11 biology and recent advances in our understanding of its role in cancer. We advocate that inhibition of IL-11 signaling may represent an emerging therapeutic opportunity for numerous cancers.

Immunosuppressive Mechanisms of Malignant Gliomas: Parallels at Non-CNS Sites

The central nervous system (CNS) possesses powerful local and global immunosuppressive capabilities that modulate unwanted inflammatory reactions in nervous tissue. These same immune-modulatory mechanisms are also co-opted by malignant brain tumors and pose a formidable challenge to brain tumor immunotherapy. Routes by which malignant gliomas coordinate immunosuppression include the mechanical and functional barriers of the CNS; immunosuppressive cytokines and catabolites; immune checkpoint molecules; tumor-infiltrating immune cells; and suppressor immune cells. The challenges to overcoming tumor-induced immunosuppression, however, are not unique to the brain, and several analogous immunosuppressive mechanisms also exist for primary tumors outside of the CNS. Ultimately, the immune responses in the CNS are linked and complementary to immune processes in the periphery, and advances in tumor immunotherapy in peripheral sites may therefore illuminate novel approaches to brain tumor immunotherapy, and vice versa.

Reprogramming the tumor microenvironment: tumor-induced immunosuppressive factors paralyze T cells

It has become evident that tumor-induced immuno-suppressive factors in the tumor microenvironment play a major role in suppressing normal functions of effector T cells. These factors serve as hurdles that limit the therapeutic potential of cancer immunotherapies. This review focuses on illustrating the molecular mechanisms of immunosuppression in the tumor microenvironment, including evasion of T-cell recognition, interference with T-cell trafficking, metabolism, and functions, induction of resistance to T-cell killing, and apoptosis of T cells. A better understanding of these mechanisms may help in the development of strategies to enhance the effectiveness of cancer immunotherapies.

High expression of interleukin-11 is an independent indicator of poor prognosis in clear-cell renal cell carcinoma

Interleukin-11 (IL-11), a member of the IL-6 family of cytokines, exerts pleiotropic oncogenic activities by stimulating angiogenesis and metastasis in many cancer types. The present study aims to evaluate the impact of IL-11 expression on recurrence and mortality of patients with clear-cell renal cell carcinoma (ccRCC). We retrospectively enrolled 193 ccRCC patients undergoing nephrectomy at a single center. Clinicopathologic features, recurrence-free survival (RFS) and overall survival (OS) were recorded. IL-11 intensity was assessed by immunohistochemistry in tumor specimens. The Kaplan–Meier method was applied to compare survival curves. Cox regression models were used to analyze the impact of prognostic factors on RFS and OS. The concordance index (C-index) was calculated to assess predictive accuracy. High IL-11 expression is associated with increased risk of recurrence and poor survival for ccRCC patients (P < 0.001 and P < 0.001, respectively), especially those with early-stage disease (TNM stage I + II). Multivariate analyses confirmed that IL-11 expression was an independent prognostic factor for RFS and OS (P = 0.006 and P = 0.008, respectively). The predictive accuracy of well-established prognostic models was improved when IL-11 expression was integrated. In conclusion, high IL-11 expression is an independent predictor of poor prognosis in ccRCC patients. It may help identify patients who could benefit from additional treatments and closer follow up.

IL-6 and related cytokines as the critical lynchpins between inflammation and cancer

Inflammatory responses play pivotal roles in cancer development, including tumor initiation, promotion, progression, and metastasis. Cytokines are now recognized as important mediators linking inflammation and cancer, and are therefore potential therapeutic and preventive targets as well as prognostic factors. The interleukin (IL)-6 family of cytokines, especially IL-6 and IL-11, is highly up-regulated in many cancers and considered as one of the most important cytokine families during tumorigenesis and metastasis. This review discusses molecular mechanisms linking the IL-6 cytokine family to solid malignancies and their treatment.

Interleukin 10 in the tumor microenvironment: a target for anticancer immunotherapy

IL-10 is an immunomodulatory cytokine that is frequently upregulated in various types of cancer. The biological role of IL-10 in cancer is quite complex; however, the presence of IL-10 in advanced metastases and the positive correlation between serum IL-10 levels and progression of disease indicates a critical role of IL-10 in the tumor microenvironment. IL-10 has been shown to directly affect the function of antigen-presenting cells by inhibiting the expression of MHC and costimulatory molecules, which in turn induces immune suppression or tolerance. Additionally, IL-10 downregulates the expression of Th1 cytokines and induces T-regulatory responses. Taken together, a combination of IL-10 antagonism and immunostimulatory treatments such as cancer vaccines, Toll-like receptor agonists, Th1 cytokines, and chemokines would be a logical approach to enhance an antitumor immune response.

Interleukin 6 mediates production of interleukin 10 in metastatic melanoma

We previously reported that substantial amounts of IL-10, an immunomodulatory cytokine, are produced by cell suspensions of fresh human metastatic melanoma tissues. Production diminished with continuous culturing of cells, which suggests a pivotal interactive role between melanoma cells and the tumor microenvironment. In this study, we found that the culture media obtained from LPS-stimulated peripheral blood mononuclear cells induced IL-10 production by metastatic melanoma cells. Of the multiple cytokines present in the conditioned culture media, IL-6 was identified as the inducer of IL-10 production. A neutralizing antibody against IL-6 completely blocked the conditioned medium-induced IL-10 production. Metastatic melanoma cells that constitutively produce low amount of IL-10 increased IL-10 production in response to recombinant human IL-6 in a dose-dependent fashion. The response to exogenously added IL-6 was less significant in melanoma cells that produced high amounts of IL-6, probably due to pre-existing autocrine stimulation of IL-10 by endogenous IL-6. On the other hand, metastatic melanoma cells that do not constitutively produce IL-10 protein did not respond to exogenous IL-6. In IL-6-responsive melanoma cells, IL-6 increased STAT3 phosphorylation and inhibition of STAT3 signaling using siRNA or inhibitors for JAKs diminished IL-6-induced IL-10 production. In addition, inhibition of MEK and PI3K, but not mTOR, interfered with IL-10 production. Taken together, the data suggest that blocking of these signals leading to IL-10 production is a potential strategy to enhance an anti-melanoma immune response in metastatic melanoma.

Clinical and immunologic effects of intranodal autologous tumor lysate-dendritic cell vaccine with Aldesleukin (Interleukin 2) and IFN-{alpha}2a therapy in metastatic renal cell carcinoma patients

PURPOSE

To evaluate the clinical and immunologic outcomes of DC (dendritic cell) vaccine with interleukin (IL)-2 and IFN-alpha 2a in metastatic renal cell carcinoma patients.

EXPERIMENTAL DESIGN

Eighteen consented and eligible patients were treated. Peripheral blood monocytes were cultured ex vivo into mature DCs and loaded with autologous tumor lysate. Treatment consisted of five cycles of intranodal vaccination of DCs (1 x 10(7) cells/1 mL Lactated Ringer's solution), 5-day continuous i.v. infusion of IL-2 (18MiU/m2), and three s.c. injections of IFN-alpha 2a (6MiU) every other day. Response Evaluation Criteria in Solid Tumors criteria were used for disease assessment. Correlative immunologic end points included peripheral blood lymphocyte cell phenotype and function as well as peripheral blood anti-renal cell carcinoma antibody and cytokine levels.

RESULTS

All patients received between two and five treatment cycles. Toxicities consisted of known and expected cytokine side effects. Overall objective clinical response rate was 50% with three complete responses. Median time to progression for all patients was 8 months, and median survival has not been reached (median follow up of 37+ months). Treatment-related changes in correlative immunologic end points were noted and the level of circulating CD4(+) T regulatory cells had a strong association with outcome. Pre-IP-10 serum levels approached significance for predicting outcome.

CONCLUSIONS

The clinical and immunologic responses observed in this trial suggest an interaction between DC vaccination and cytokine therapy. Our data support the hypothesis that modulation of inflammatory, regulatory, and angiogenic pathways are necessary to optimize therapeutic benefit in renal cell carcinoma patients. Further exploration of this approach is warranted.

Significant association of interleukin 10 receptor mRNA levels with renal cell carcinoma metastasis

Immunosuppressive cytokine, interleukin 10 (IL-10), is associated with progression of the renal cell carcinoma (RCC). However, the roles of its cell surface receptor, interleukin 10 receptor (IL-10R), remain elusive. We quantified IL-10R mRNA expression in paired tumor and non-tumor samples from the surgical specimens of 71 consecutive patients with RCC using a real-time reverse transcription polymerase chain reaction (RT-PCR). The absolute level of IL-10R mRNAs in tumor and non-tumor tissues did not correlate with the malignant and metastatic profiles. The relative yields of the PCR product from the tumor tissue to that from the corresponding non-tumor tissue (T/N) for the expression of IL-10R mRNAs were calculated. A high T/N ratio of IL-10R correlated with poor differentiation (P < 0.001) and metastasis (P < 0.0001). By univariate analysis, a high T/N ratio of IL-10R predicted a shortened overall survival in all cases (P < 0.01). These findings suggest that IL-10R is associated with the progression of RCC.

CD69 on CD56+ NK cells and response to chemoimmunotherapy in metastatic melanoma

BACKGROUND

The few chemoimmunotherapy trials that together with dacarbazine (DTIC) and interferon-alpha 2a (IFNalpha), include retinoic acid (RA), did not include detailed immunological evaluation of functional and phenotypic natural killer (NK) cell characteristics, and have shown contradictory clinical results.

MATERIALS AND METHODS

Malignant melanoma (MM) patients undergoing phase II-randomized chemoimmunotherapy trials were treated with DTIC, IFNalpha (Hoffmann-La Roche) (group A, n = 31), and with DTIC, IFNalpha and 13-cis-RA (Isotretinoin, Hoffmann-La Roche, Basel, Switzerland) (group B, n = 29). Patients and 42 healthy controls were evaluated by FACS flow analyses for CD3/CD56/CD69 positive cells, NK cytotoxicity in fresh peripheral blood lymphocytes (PBL) and for interferon regulatory factor-1 mRNA expression by reverse transcriptase polymerase chain reaction in treated PBL.

RESULTS

The addition of RA to a DTIC-IFN regime did not bring any therapeutical benefit in terms of response or survival. Immunological follow-up on days 1, 6 and 27 of each therapy cycle shows a significant increase in NK cell activity in both groups, only on day 6 of the first cycle, while CD69+CD56+ expression increased significantly on day 6 of each therapy cycle, in both groups. Evaluation of the dynamics of expression of IRF-1 of in vitro treated PBL, shows its strong and prompt up-regulation by IFNalpha and synergistic effect of IFNalpha and RA combination.

CONCLUSION

The dynamics of the increase in CD69 early activation antigen expression on CD56+ NK cells is systematic and serial with the increase being significantly higher on day six of the first cycle in group B patients with clinical response, compared to those without, indicating possible predictive value of CD69 expression for clinical response to chemoimmunotherapy.

Immune suppression in renal cell carcinoma

The clear evidence that tumor-infiltrating lymphocytes with anti-tumor activity exist in situ raises the question why renal cell carcinomas (RCCs) progress in vivo. A complex array of factors and pathways has been identified that impinges on innate and adaptive effector cells thereby inhibiting their activity against RCCs. The current picture of suppressive mechanisms that contribute to the failure of the immune system to control RCCs is reviewed here. Understanding these complex host-tumor interactions has broad implications for successful application of cytokine therapy and other forms of immunotherapy for RCC.

Developing a rational tumor vaccine therapy for renal cell carcinoma: immune yin and yang

In patients with progressive malignancy, the natural balance between proinflammatory (Yang) and inhibitory (regulatory or Yin) immune pathways is disrupted and favors cancer-specific immune suppression. Therapy with interleukin 2 (IL-2) can mobilize immune effector cells that recognize and destroy cancer. High-dose IL-2 is the only therapy that has consistently induced complete durable remissions in patients with metastatic renal cell carcinoma (RCC) but only in a few of them. The lack of benefit in most metastatic RCC patients is likely due to the ineffective manipulation of other immune circuits critical in regulating tumor cytotoxic pathways. The limited clinical activity of IL-2, RCC vaccines, and other immune therapies to date leads us to postulate that effective clinical treatment strategies will need to simultaneously enhance proinflammatory pathways and disrupt regulatory pathways. We present preliminary studies in RCC patients to highlight the complexity of the regulatory pathways and our approach to shifting the balance of proinflammatory and regulatory immune pathways using dendritic cell-tumor lysate vaccine followed by cytokine therapy.

Changes in cytokine production and morphology of murine lymphoma NK/Ly cells in course of tumor development

The main goal of this study was to evaluate if specific cytokine expression in the NK/Ly lymphoma cells might be involved in development of intoxication in the tumor-bearing animals. RT-PCR analysis was used to study an expression of mRNA coding for IL-1α, IL-6, TNF-α, TNF-β and VEGF. ELISA was used to evaluate IL-6 and IFN-γ concentration in the ascitic fluid. Cytomorphological investigation of tumor cells was done after standard Romanovsky-Giemsa staining, and chromatin staining was performed with hematoxyline and neutral red. Lactate dehydrogenase and acid phosphatase release from tumor cells was estimated. It was revealed that the level of mRNA coding for VEGF and IL-6 was significant in the lymphoma cells. The level of VEGF mRNA was initially high and did not change during tumor progression, while the level of expression of IL6 mRNA was low at the initial stages of tumor growth and markedly increased (up to 5-fold) at the terminal stages. The obtained data on IL-6 mRNA expression were confirmed by ELISA, which showed more than 6-fold increase (from 90 to 570 pg/ml) in the IL-6 concentration in the ascitic fluid at late stages of NK/Ly tumor development. On the contrary to IL-6, concentration of IFN-γ in the ascitic fluid was very high at early stages of tumor development (1,000 pg/ml) and it markedly decreased (up to 30-fold, 30 pg/ml) at the terminal stages of tumor development. The high levels of IL-6 mRNA in tumor cells and IL-6 content in extracellular medium correlated with cell deterioration, as revealed by cytomorphologic study and the release of intracellular enzymes into extracellular medium. We suggest that an enhanced production and release of IL-6 by lymphoma cells can cause intoxication and exhaustion of the organism observed at terminal stages of tumor growth.

Interleukin-6 and vascular endothelial growth factor release by renal cell carcinoma cells impedes lymphocyte-dendritic cell cross-talk

Anti-tumour T cell response requires antigen presentation via efficient immunological synapse between antigen presenting cells, e.g. dendritic cells (DC), and specific T cells in an adapted Th1 cytokine context. Nine renal cell carcinoma (RCC) primary culture cells were used as sources of tumour antigens which were loaded on DC (DC-Tu) for autologous T cell activation assays. Cytotoxic activity of lymphocytes stimulated with DC-Tu was evaluated against autologous tumour cells. Assays were performed with 75 grays irradiated tumour cells (Tu irr) and with hydrogen peroxide +/- heat shock (Tu H(2)O(2) +/- HS) treated cells. DC-Tu irr failed to enhance cytotoxic activity of autologous lymphocytes in seven of 13 assays. In all these defective assays, irradiated tumour cells displayed high interleukin (IL)-6 and vascular endothelial growth factor (VEGF) release. Conversely, when tumour cells released low IL-6 levels (n = 4), DC-Tu irr efficiently enhanced CTL activity. When assays were performed with the same RCC cells treated with H(2)O(2) + HS, DC-Tu stimulation resulted in improved CTL activity. H(2)O(2) + HS treatment induced post-apoptotic cell necrosis of tumour cells, totally abrogated their cytokine release [IL-6, VEGF, transforming growth factor (TGF)-beta1] and induced HSP70 expression. Taken together, data show that reduction in IL-6 and VEGF release in the environment of the tumour concomitantly to tumour cell HSP expression favours induction of a stronger anti-tumour CTL response.

Serum Interleukin-11 in Patients with Benign Prostatic Hyperplasia and Prostate Cancer

To clarify whether serum levels of interleukin-11 (IL-11) could be a useful marker in patients with prostate cancer, serum IL-11 was determined in 73 and 23 men with prostate cancer and benign prostate hyperplasia (BPH), respectively, before treatment. There were no statistical differences of IL-11 levels between patients with prostate cancer and BPH. Patients with hormone-resistant prostate cancer had a significantly higher level of IL-11 than those with untreated cancer. Serum IL-11 levels may be a potential tumor marker for prostate cancer progression.

Expression of transforming growth factor beta in renal cell carcinoma and matched non-involved renal tissue

TGFbeta1 is one of several cytokines produced by proximal tubular and renal cancer cells. Previous studies have been mainly focused on determining plasma or serum TGFbeta levels, its effect on RCC cultures, and the expression of TGFbeta mRNA. Cancerous and autologous normal kidney samples were obtained from 24 patients treated by radical nephrectomy. TGFbeta1 expression was determined using a semi quantitative Western blot analysis and immunohistochemistry. Blot densities and immunohistochemical expression intensities in normal and neoplastic tissue were compared, and subsequently correlated to tumor stage, histological type and nuclear grade. All tissue samples examined expressed TGFbeta1; mean tumor to non-involved kidney spot density ratio correlated with advancing stage and higher nuclear grade. The overexpression of TGFbeta1 in certain RCCs may partially explain their resistance to the growth suppression action of TGFbeta. The correlation with tumor stage and grade indicates a possible role in the development of metastatic potential as well as in host's immune response modulation.

A pilot trial of tumor lysate-loaded dendritic cells for the treatment of metastatic renal cell carcinoma

Cultured tumor lysate-loaded dendritic cells (TuLy-DC) have been demonstrated in vitro to stimulate potent immune modulations and generate significant antitumor response. We report the results of a pilot trial of TuLy-DC vaccine for patients with metastatic renal cell carcinoma (mRCC). Fourteen mRCC patients underwent nephrectomy to obtain autologous TuLy prepared by subjecting tumor cells to 3 freeze/thaw cycles. Dendritic cells were generated from peripheral blood CD14+ precursors cultured in the presence of GM-CSF, IL-4, and 10% autologous serum. Patients received one vaccination of TuLy alone as an immunologic control, followed by 3 weekly vaccinations of DC-TuLy injected intradermally in the midaxillary region. Peripheral blood lymphocytes were collected before and after weekly vaccines and were assessed for changes in phenotype, cytotoxicity, and cytokine profile. The TuLy-DC vaccine was successfully prepared and administered to 12 patients, whereas 2 patients did not receive vaccine treatment due to declines in postoperative performance status. The vaccines were well tolerated, with only grade 1 toxicities noted. One patient had a partial response to treatment that did not correspond to any significant change in immunologic profile. This pilot trial demonstrated both the safety and feasibility of reliably preparing a DC-based vaccine for mRCC patients. Our data suggest that autologous TuLy-DC vaccines generate only limited clinical response. Further clinical studies are needed to identify the most potent treatment regimen that can consistently mediate an antitumor immune response in vivo.

Cytokines affect resistance of human renal tumour cells to complement-mediated injury

Overexpression of membrane-bound complement regulatory proteins (mCRPs) on tumour cells may hamper the effect of immunotherapy with complement-activating monoclonal antibody (MoAb). Therefore, it is important to investigate whether cytokines can downregulate the expression of mCRP on tumour cells. In this study, the effect of 10 cytokines on the expression of the mCRP CD46, CD55 and CD59 and the renal tumour-associated antigen G250/MN/CAIX on four human renal tumour cell lines and proximal tubular epithelial cells was determined by flow cytometry. In addition, it was measured whether changes in the expression of the classical pathway regulatory proteins CD55 and CD59 had an effect on C3 deposition and lysis. Interleukin-1beta (IL-1beta) consistently downregulated the expression of CD46 and CD59; IL-4 consistently downregulated the expression of CD46 and transforming growth factor-beta1, consistently downregulated the expression of both CD46 and CD55. However, treatment with IL-1beta and IL-4 also decreased the expression of G250/MN/CAIX. Changes in the expression of CD55 and CD59 were associated with changes in the amount of C3 deposited and the extent of complement-mediated lysis, respectively. This suggests that clinical immunotherapy, consisting of treatment with cytokines and MoAb, may induce either up- or downregulation of CD55 or CD59 and thus affect the effectiveness of immunotherapy with MoAb.

IL-2 gene and antisense TGF-beta1 strategies counteract HSV-2 transformed tumor progression

The H238 tumor cells are Herpes simplex virus type 2-transformed BALB/c mouse fibroblasts that constitutively express transforming growth factor (TGF-beta1). TGF-beta can diminish immune capacity, whereas interleukin 2 (IL-2) is stimulatory to the immune system and can counteract the negative effects of TGF-beta1. The H238-BALB/c system provides a syngeneic model to evaluate new strategies with the potential to ameliorate tumor-induced immune depression. Plasmids expressing either antisense TGF-beta1 or murine Il-2 were constructed and stably transformed cells generated (masH238 and H238-IL2, respectively). In vitro measurements (ELISA and RT-PCR) demonstrated a >70% decrease in TGF-beta1 secretion by the masH238 tumor cells, and significant levels of IL-2 production by the H238-IL2 transfected cells when compared to wild type and control plasmid-transfected H238 cells. BALB/c mice injected subcutaneously with the masH238 cells developed significantly smaller tumors than the controls. Mice injected with H238-IL-2 cells developed tumors that failed to progress relative to control tumor growth. The differences in tumor growth in the mice were associated with enhanced immune reactivity and an increased response to T lymphocyte mitogens. Significant differences were also noted in lymphocyte populations and expression of CD25 and CD71 activation markers in the blood and spleens of mice receiving transfected tumor cells. Collectively, the data demonstrate that strategies employing antisense TGF-beta1 and IL-2 expression by transfected tumor cells can counteract the progression of a TGF-beta1-secreting tumor and enhance immune function involving modulation of T lymphocyte populations.

Transforming growth factor-beta induces apoptosis in antigen-specific CD4+ T cells prepared for adoptive immunotherapy

Transforming growth factor-beta (TGF-beta), found at the site of most tumors, has been recognized as one of the mechanisms involved in tumor immunological escape. To evaluate its impact on adoptive immunotherapy against cancer, we examined the susceptibility of tumor-specific T cells to TGF-beta in the setting of these T cells being prepared for adoptive transfer. Hepatitis B virus (HBV)-specific CD4(+) T cells were ex vivo generated by activating with HBV-transfected dendritic cells and selecting with antibodies to CD25 activation molecules, and then expanded with antibodies to CD3/CD28. These T cells expressed higher levels of the type II TGF-beta receptor than nai;ve T cells and exhibited enhanced apoptosis when exposed to TGF-beta. The underlying apoptotic pathway was linked to the dissipation of the mitochondrial inner membrane potential and activation of caspase-9. The absence of caspase-8 activity in TGF-beta-treated T cells suggests that the death receptor system may not be involved in this type of apoptosis. Interleukin-2 (IL-2), which is concomitantly administered with tumor-specific T cells in adoptive immunotherapy, was unable to protect HBV-specific CD4(+) T cells from the pro-apoptotic effect of TGF-beta when added simultaneously with TGF-beta. Interesting, IL-2-pretreated T cells displayed the type II TGF-beta receptor at lower levels and were more resistant to TGF-beta. Together, our findings indicate that the effectiveness of adoptive cancer immunotherapy may be impaired by tumor-derived TGF-beta and appropriate manipulation of exogenous IL-2 might overcome this hurdle.

HLA-G Molecules: from Maternal–Fetal Tolerance to Tissue Acceptance

Over the past few years, HLA-G, the non-classical HLA class I molecule, has been the center of investigations that have led to the description of its specific structural and functional properties. Although located in the HLA class I region of chromosome six, the HLA-G gene may be distinguished from other HLA class I genes by its low polymorphism and alternative splicing that generates seven HLA-G proteins, whose tissue-distribution is restricted to normal fetal and adult tissues that display a tolerogeneic function toward both innate and acquired immune cells. We review these points, with special emphasis on the role of HLA-G in human pathologies, such as cancer, viral infection, and inflammatory diseases, as well as in organ transplantation.

Prognostic significance of cytokine modulation in non-small cell lung cancer

Increased production of immunosuppressive interleukin-10 (IL-10) by non-small cell lung cancer (NSCLC) and increased serum IL-10 concentrations in NSCLC-patients have recently been correlated to reduced survival. We earlier demonstrated suppression of IL-2 secretion in whole blood cell cultures of NSCLC-patients. We now analyzed the influence of IL-2 secretion on survival in NSCLC-patients and the influence of IL-10 on IL-2 secretion. The correlation of the IL-2 producing ability of whole blood cells in response to PHA in 90 NSCLC-patients at the time of diagnosis to survival was calculated by Crit-level, the Kaplan-Meier method and the log-rank test. With a cut-off value of IL-2 production of 1,100 pg/ml by whole blood cells the difference in survival was significant with a p-value of 0.014. In the group with high and low IL-2, median survival was 14.1 and 9.7 months, respectively. In the subgroup of 33 surgically-treated patients the difference in survival was significant with a p-value of 0.011. In 14 patients with surgical resection of the tumor and high IL-2 at diagnosis and 19 patients with surgical resection, but low IL-2 at diagnosis, median survival was 86.2 and 11.3 months, respectively. Secretion of IL-2 in whole blood cell cultures from healthy individuals was inhibited in a dose-dependent manner upon addition of IL-10. Taken together, suppression of IL-2 secretion has prognostic significance for survival of NSCLC-patients and may be mediated by tumor-derived IL-10.

Activated human CD4+ T cells induced by dendritic cell stimulation are most sensitive to transforming growth factor-beta: implications for dendritic cell immunization against cancer

The secretion of immunosuppressive factors like transforming growth factor-beta (TGF-beta) by tumor cells has been recognized as one of the mechanisms involved in tumor immunological escape. This study aimed to examine whether dendritic cell (DC) immunization could reverse TGF-beta-induced immunosuppression by simulating the in vivo interaction among infused DCs, host T cells, and tumor-secreted TGF-beta in an in vitro study. We found that both immature and mature DCs were relatively resistant to TGF-beta. The addition of TGF-beta to naive human CD4+ T cells, which are required by genetically modified DC to elicit antitumor immunity, resulted in their hyporesponsiveness to DC stimulation in a dose-dependent manner. When activated by allogeneic DCs in the presence of TGF-beta, CD4+ T cells displayed a reduced capacity to proliferate. More importantly, activated CD4+ T cells induced by DC stimulation were very sensitive to TGF-beta, and this susceptibility was enhanced by their previous exposure to TGF-beta. The underlying mechanism was linked to TGF-beta-induced apoptosis of activated T cells. However, the presence of stimulation from DC or antibodies to CD3 plus CD28 could partly reverse the immunosuppressive effect of TGF-beta on activated CD4+ T cells. Taken together, our results indicate that the efficacy of DC immunization may be impaired by tumor-derived TGF-beta.

Cytokine secretion: clinical relevance of immunosuppression in non-small cell lung cancer

Increased production of immunosuppressive IL-10 by non-small cell lung cancer (NSCLC) and increased plasma IL-10 concentrations in NSCLC-patients have recently been correlated to reduced survival. We earlier demonstrated suppression of IL-2 secretion in NSCLC-patients. We now analyzed the influence of IL-2 suppression on survival in NSCLC-patients and influence of IL-10 on IL-2 secretion. The correlation of the IL-2-concentration in whole blood cell cultures from 90 NSCLC-patients at the time of diagnosis to survival was analyzed by using crit-level, the Kaplan-Meier method and the log-rank test. IL-2 secretion capacity at the time of diagnosis significantly influenced survival in NSCLC-patients. With a cut-off value for IL-2 of 1100 pg/ml, the difference in survival was significant with a P-value of 0.014 in the whole patient group. In the subgroup of surgically treated patients (n=33), survival was different with a P-value of 0.011. Moreover, secretion of IL-2 was inhibited in a dose-dependent manner upon addition of IL-10 in whole blood cell cultures from normal individuals. Thus, suppression of IL-2 secretion is predictive for survival of NSCLC-patients and may be mediated by tumor-derived IL-10.

Comparison of serum interleukin-10 (IL-10) levels between normal volunteers and patients with advanced melanoma

Melanoma is an immunoresponsive malignancy. Interleukin-10 (IL-10) is a potent regulator of immunosuppression. The purpose of this research was to define the relationship of serum IL-10 to survival in patients with metastatic melanoma. Forty-one melanoma patients and 50 normal volunteers were analyzed. The median IL-10 level as determined by enzyme-linked immunosorbent assay (ELISA) in melanoma patients was 8.75 pg/ml compared to < 3.0 pg/ml in normal volunteers (p = 0.0001). Survival of melanoma patients with an IL-10 level above 10.0 pg/ml was 365 days compared to 557 days in patients with IL-10 levels less than 10.0 pg/ml (p = 0.0259, Wilcoxon). Elevated IL-10 levels were correlated with poor survival.

Cytokine secretion associated with the clearance of apoptotic bodies in renal cell carcinoma patients

The factors determining the outcome of immunotherapy in metastatic renal cell carcinoma (RCC) patients remain elusive. Macrophages from normal donors that phagocytose apoptotic cells secrete the immunosuppressive cytokine IL-10 in vitro. Conversely, IL-10 genetic deletion enhances the immunogenicity of apoptotic tumor cells in vivo. Elevated pre-treatment levels of IL-10 are associated with an unfavorable outcome of RCC. We examined whether the ability to release IL-10 by macrophages from RCC patients that phagocytosed apoptotic cells correlated with the outcome of immunotherapy. To this aim, we derived macrophages from 30 patients with metastatic RCC and from 21 healthy subjects (11 sex- and age-matched healthy controls and 10 younger donors). Patients either had a clinical response after immunotherapy, with a median survival after treatment of more than 18 months (n = 16), or were beginning immunotherapy after diagnosis of metastatic disease (n = 14). Macrophages from responding patients challenged with apoptotic cells released significantly less IL-10 than controls (p = 0.0075) and recently diagnosed patients (p = 0.0198), as ascertained by a 2-sided Student's t-test. This was not because macrophages from responding patients lost the ability to secrete IL-10, because antibody opsonization of apoptotic cells rescued IL-10 secretion. In contrast, macrophages from all groups of donors released similar amounts of TNF-alpha. The failure in IL-10 secretion by engulfing macrophages of responding subjects may exalt the immunogenicity of dying tumor cells, contributing to the success of immunotherapy.

Elevated plasma TGF-beta1 in renal diseases: cause or consequence?

We previously reported elevated levels of TGF-beta1 in patients with renal carcinoma. Certain aspects led us to ask whether they might be caused by chronic damage to the kidney(s). Here we report on an extended set of patients with various renal diseases, lung cancer, humoral immunodeficiency and controls. For latent TGF-beta1 in plasma, we find that the control, immunodeficiency, lung cancer and kidney transplant groups do not differ significantly (means, 7.0-8.8 ng/ml). Also, acute short-term renal stress (extracorporal lithotrypsy) does not lead to an increase of TGF-beta1. However, the pyelonephritis patients present with levels of 19.0 ng/ml, chronic extracorporal dialysis patients with 15.5 ng/ml, and renal cell carcinoma patients with 22.8 ng/ml. For active TGF-beta1 these findings are exactly recovered. For serum levels, only the renal carcinoma group presents with significantly elevated levels of TGF-beta1. Kidney transplantation seems to normalize TGF-beta1 levels, while in the kidney cancer patients surgery has an effect only in part of the group. We conclude that elevated plasma TGF-beta1 levels are common in at least two chronic renal disease conditions, and that it normalizes with restoration of renal function. It is tempting to speculate that chronic elevation of TGF-beta1 in these patients may be critically involved in these conditions predisposing to renal cancer.

Regeneration and tolerance factor: a correlate of human immunodeficiency virus-associated T-cell activation

Human immunodeficiency virus (HIV) infection causes extensive phenotypic alterations in lymphocytes. Cellular markers that are normally absent or expressed at low levels on quiescent cells are upregulated throughout the disease course. The transmembrane form of regeneration and tolerance factor (RTF) is expressed at negligible levels on resting T cells but is quickly upregulated following in vitro stimulation and activation. Recently, we reported that expression of RTF was significantly higher in cells from HIV-seropositive (HIV(+)) individuals than in cells from HIV-seronegative (HIV(-)) individuals. Because T cells from HIV(+) individuals express markers reflecting chronic activation, we hypothesized that these in vivo-activated cells would coexpress RTF. Flow cytometry was used to assess RTF expression on activated (CD38(+) and HLA-DR(+)) CD4(+) and CD8(+) T cells. HIV(+) individuals had higher percentages of RTF(+) CD38(+) (P < 0.0001) or RTF(+) HLA-DR(+) (P = 0.0001) CD4(+) T cells than HIV(-) individuals. In HIV(+) individuals, increased percentages of CD4(+) T cells that were RTF(+), RTF(+) CD38(+), and RTF(+) HLA-DR(+) correlated inversely with the absolute number and percentage of CD4(+) T cells and correlated positively with plasma beta(2)-microglobulin concentrations. HIV(+) individuals had higher percentages of CD8(+) T cells that were RTF(+) CD38(+) (P = 0.0001) or RTF(+) HLA-DR(+) (P = 0.0010). In HIV(+) individuals, increased percentages of CD8(+) T cells that were RTF(+) HLA-DR(+) correlated inversely with the percentage of CD4(+) T cells, and high percentages of CD8(+) T cells that were RTF(+) CD38(+) correlated positively with plasma beta(2)-microglobulin levels. These findings strongly suggest that increased RTF expression is a correlate of HIV-associated immune system activation.

Expression of regeneration and tolerance factor on B cell chronic lymphocytic leukemias: a possible mechanism for escaping immune surveillance

Regeneration and tolerance factor (RTF) is a protein expressed on developing tissue such as the thymus and the placenta. RTF has been reported to down-regulate cell-mediated immune responses. To examine the potential role of tumor-derived RTF to suppressing antitumor responses, we analyzed a panel of seven B cell tumor lines for the membrane RTF using a fluorescein isothiocyanate (FITC) conjugated monoclonal antibody, which reacts with membrane RTF. All the B cell tumor lines we examined express RTF on the cell surface. We also tested conditioned media from these B cell lines for their ability to suppress IL-2R expression on activated cells. Conditioned media from each B cell line suppressed IL-2R expression on activated Jurkat T cells and activated peripheral blood mononuclear cells. A monoclonal antibody to the biologically active portion of RTF reversed this suppressive activity. Finally, the tumor cell population from patients with chronic lymphocytic leukemia was found to express cell surface RTF. Thus, RTF expression could be a new mechanism used by tumor cells to escape immune surveillance.

Interleukin 10 (IL-10): an immunosuppressive factor and independent predictor in patients with metastatic renal cell carcinoma

Interleukin 10 (IL-10) is an immunosuppressive factor and has been detected in tumour cell cultures of renal cell carcinoma and of malignant melanoma. IL-10 has been described as a cytokine of the Th2 response; it is able to suppress antigen-presenting cells (APCs) and may lead to down-regulation of HLA class I and II molecules on dendritic cells and to anergy of T-lymphocytes. We evaluated pretreatment serum levels of soluble IL-10 and various clinical parameters to determine their prognostic value in 80 advanced renal cell carcinoma patients seen at our institution between May 1990 and April 1996. For statistical evaluation we used both univariate and multivariate Cox proportional hazards models. An elevated pretreatment serum level of IL-10 was a statistically independent predictor of unfavourable outcome (P < 0.0028), in addition to the well-known clinical and biochemical risk factors. These data support risk stratification for future therapeutic trials and identify a predictor which needs to be validated in prospective studies and may potentially influence decision making in palliative management of patients with metastatic renal cell carcinoma. These data also suggest a potential role of IL-10 in the development of advanced renal cell carcinoma and in the future design of therapeutic strategies.

Transforming Growth Factor-β1 Polarizes Murine Hematopoietic Progenitor Cells to Generate Langerhans Cell-Like Dendritic Cells Through a Monocyte/Macrophage Differentiation Pathway

We have recently demonstrated that CD11b−/dullCD11c+ and CD11b+hiCD11c+ dendritic cell (DC) precursor subsets represent two distinct DC differentiation pathways from murine bone marrow lineage-phenotype negative (Lin−)c-kit+ hematopoietic progenitor cells (HPCs) stimulated with granulocyte-macrophage colony-stimulating factor (GM-CSF) + stem cell factor (SCF) + tumor necrosis factor  (TNF). We show here that transforming growth factor-β1 (TGF-β1) significantly inhibits the generation of these CD11b−/dullCD11c+ and CD11b+hiCD11c+ DC precursors. Phenotypically, this inhibitory effect was accompanied by markedly suppressed expression of Ia and CD86 antigens as well as major histocompatibility complex (MHC) class II transactivator (CIITA) and CC-chemokine receptor 7 (CCR7) mRNAs in Lin−c-kit+ HPC cultures stimulated with GM-CSF + SCF + TNF at day 6. TGF-β1 could also suppress mature DC differentiation from CD11b+hiCD11c+ DC precursors, but not the differentiation from CD11b−/dullCD11c+ DC precursors. In the absence of TNF, TGF-β1 markedly suppressed the expression of CIITA and CCR7 mRNAs in GM-CSF + SCF-stimulated Lin−c-kit+ HPCs at either day 6 or day 12 and induced the differentiation solely into monocytes/macrophages as evident in morphology, active phagocytic, and endocytic activities. These cells expressed high levels of F4/80 and E-cadherin antigens, but low or undetectable levels of Ia, CD86, and CD40 molecules. However, upon the stimulation with TNF + GM-CSF, these cells could further differentiate into mature DCs expressing high levels of Ia and E-cadherin, characteristics for Langerhans cells (LCs), and gained the capacity of enhancing allogenic MLR. Taken together, all of these findings suggest that TGF-β1 polarizes murine HPCs to generate LC-like DCs through a monocyte/macrophage differentiation pathway.

Transforming Growth Factor-β1 Polarizes Murine Hematopoietic Progenitor Cells to Generate Langerhans Cell-Like Dendritic Cells Through a Monocyte/Macrophage Differentiation Pathway

We have recently demonstrated that CD11b−/dullCD11c+ and CD11b+hiCD11c+ dendritic cell (DC) precursor subsets represent two distinct DC differentiation pathways from murine bone marrow lineage-phenotype negative (Lin−)c-kit+ hematopoietic progenitor cells (HPCs) stimulated with granulocyte-macrophage colony-stimulating factor (GM-CSF) + stem cell factor (SCF) + tumor necrosis factor  (TNF). We show here that transforming growth factor-β1 (TGF-β1) significantly inhibits the generation of these CD11b−/dullCD11c+ and CD11b+hiCD11c+ DC precursors. Phenotypically, this inhibitory effect was accompanied by markedly suppressed expression of Ia and CD86 antigens as well as major histocompatibility complex (MHC) class II transactivator (CIITA) and CC-chemokine receptor 7 (CCR7) mRNAs in Lin−c-kit+ HPC cultures stimulated with GM-CSF + SCF + TNF at day 6. TGF-β1 could also suppress mature DC differentiation from CD11b+hiCD11c+ DC precursors, but not the differentiation from CD11b−/dullCD11c+ DC precursors. In the absence of TNF, TGF-β1 markedly suppressed the expression of CIITA and CCR7 mRNAs in GM-CSF + SCF-stimulated Lin−c-kit+ HPCs at either day 6 or day 12 and induced the differentiation solely into monocytes/macrophages as evident in morphology, active phagocytic, and endocytic activities. These cells expressed high levels of F4/80 and E-cadherin antigens, but low or undetectable levels of Ia, CD86, and CD40 molecules. However, upon the stimulation with TNF + GM-CSF, these cells could further differentiate into mature DCs expressing high levels of Ia and E-cadherin, characteristics for Langerhans cells (LCs), and gained the capacity of enhancing allogenic MLR. Taken together, all of these findings suggest that TGF-β1 polarizes murine HPCs to generate LC-like DCs through a monocyte/macrophage differentiation pathway.

Engagement of cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) induces transforming growth factor beta (TGF-beta) production by murine CD4(+) T cells

Evidence indicates that cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) may negatively regulate T cell activation, but the basis for the inhibitory effect remains unknown. We report here that cross-linking of CTLA-4 induces transforming growth factor beta (TGF-beta) production by murine CD4(+) T cells. CD4(+) T helper type 1 (Th1), Th2, and Th0 clones all secrete TGF-beta after antibody cross-linking of CTLA-4, indicating that induction of TGF-beta by CTLA-4 signaling represents a ubiquitous feature of murine CD4(+) T cells. Stimulation of the CD3-T cell antigen receptor complex does not independently induce TGF-beta, but is required for optimal CTLA-4-mediated TGF-beta production. The consequences of cross-linking of CTLA-4, together with CD3 and CD28, include inhibition of T cell proliferation and interleukin (IL)-2 secretion, as well as suppression of both interferon gamma (Th1) and IL-4 (Th2). Moreover, addition of anti-TGF-beta partially reverses this T cell suppression. When CTLA-4 was cross-linked in T cell populations from TGF-beta1 gene-deleted (TGF-beta1(-/-)) mice, the T cell responses were only suppressed 38% compared with 95% in wild-type mice. Our data demonstrate that engagement of CTLA-4 leads to CD4(+) T cell production of TGF-beta, which, in part, contributes to the downregulation of T cell activation. CTLA-4, through TGF-beta, may serve as a counterbalance for CD28 costimulation of IL-2 and CD4(+) T cell activation.

Postoperative plasma interleukin-6 in patients with renal cancer correlates with C-reactive protein but not with total fibrinogen or with high molecular weight fibrinogen fraction

The concentration of fibrinogen (Fb) and its fractions, the levels of interleukin-6 (I1-6), C-reactive protein (CRP), and immunoglobulin G (IgG) were determined in 38 patients operated on because of renal cancer. The increased Fb and I1-6 concentrations were found in approximately one-half of the patients with malignancy. The relations among the high molecular weight (HMW) and two low molecular weight (LMW and LMW') fibrinogen fractions in these patients before surgery did not differ from the corresponding relations in normal subjects. The levels of all (except IgG) compounds studied increased after surgery and the peak of I1-6 was observed on the first postoperative day but that of CRP on the third day. The concentrations of total Fb and of its HMW fraction were the highest also on the third postoperative day and this was in contrast with the decline of low molecular weight fractions at the same time. These variations of estimated variables can be regarded as being relevant to the acute phase response. We have noted a correlation between the maximal concentrations of I1-6 and CRP, but not between the corresponding concentrations of Il-6 and total Fb or HMW Fb; this may suggest that the concentration of Fb is also under the control of a factor other than I1-6.

Neutralizing anti-IL-10 antibody upregulates the induction and elicitation of contact hypersensitivity

Various cytokines have been shown to modulate the acquisition and expression of delayed-type hypersensitivity. In a mouse model, we tested the notion that neutralization of interleukin-10 (IL-10), a cytokine that inhibits T cell-mediated reactions, would upregulate delayed-type hypersensitivity. We used two different monoclonal antibodies with specificity for murine IL-10 and used allergic contact dermatitis as a prototypical example of delayed-type hypersensitivity. When anti-IL-10 antibody was given at the time of sensitization to a contact allergen, there was a substantial increase in the induced contact hypersensitivity (CHS). In other experiments, the challenge reactions to contact allergen in routinely sensitized mice were increased when anti-IL-10 antibody was given at the time of challenge. Primary irritant reactions to croton oil were increased but only if anti-IL-10 antibody was given at the time of challenge and not when it was given a week previously. It appears that anti-IL-10 antibody can potentiate CHS reactivity by inactivating otherwise downregulating endogenous IL-10.