Lung squamous cell carcinoma and adenocarcinoma cell lines use different mediators to induce comparable phenotypic and functional changes in human monocyte-derived dendritic cells

Tumor-derived immunosuppressive factors contribute to the evasion of malignant cells from the immune response, partially by hampering dendritic cell (DC) differentiation. Here, we analyze whether soluble mediators released by the most frequent histological types of non-small cell lung carcinoma, squamous cell carcinoma (SCC), and adenocarcinoma (AD) cells, affect the development and functionality of DC. Monocytes from healthy donors were differentiated in vitro into DC with granulocyte–macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)-4, in the absence or presence of soluble factors (SF) from SCC or AD cell lines. Monocytes were differentiated in parallel into macrophages (MΦ s) with macrophage colony-stimulating factor (M-CSF). SF-treated DC were phenotypically and functionally more similar to MΦ s than to untreated DC [control DC (Ctrl-DC)]. Both tumors increased myelomonocytic markers (CD14, CD16, CD32, and CD163) and impaired CD1a expression on DC. SF-treated DC increased their endocytic capacity, and released higher levels of IL-6, IL-10, and lower levels of IL-12, compared to Ctrl-DC. SF-treated DC were poor stimulators in mixed lymphocyte reactions, and naïve CD4⁺ T lymphocytes stimulated by SF-treated DC secreted lower levels of interferon (IFN)-γ and higher amounts of IL-10 than controls. In contrast to AD, the effects caused by SCC were mostly abolished by IL-6 neutralization during monocyte differentiation. However, tumor-derived prostanoid blockade recovered the IFN-γ levels secreted by lymphocytes stimulated with SF-treated DC, whereas prostanoid/IL-6 or prostanoid/IL-10 blockade decreased IL-10 production only by SCC-DC-stimulated lymphocytes. Thus, we provide evidence that lung SCC and AD cause comparable deficiencies on DC in vitro, skewing monocyte differentiation from DC to MΦ -like cells, but most of these changes occurred via different mediators.     

Generation of potent anti-tumor immunity in mice by interleukin-12-secreting dendritic cells

To induce cytolytic immunity, dendritic cells (DCs) need to release bioactive interleukin-12 (IL-12) p70 heterodimeric molecules. To study the role of IL-12 for the generation of an anti-tumor immune response, we generated two classes of DCs. (1) DCs were initiated to secrete IL-12 by exposure to LPS/IFN- for 2 h resulting, as demonstrated in vitro, in continued IL-12 release for another 24 h (termed active DCs). (2) DCs were exposed to LPS/IFN- for 24 h and injected into mice at a time point when IL-12 production had ceased (termed exhausted DCs). These two classes of DCs were probed for their capacity to induce a cytolytic anti-tumor immune response in vivo in a syngeneic mouse tumor model. The mouse tumor cell line K-Balb was engineered to express neomycin phosphotransferase (NPT) as a model tumor antigen. DCs were charged with various NPT-derived antigens, including recombinant NPT protein, whole tumor cell lysate and NPT-derived synthetic peptides, and the induction of in vivo anti-tumor immunity was determined by measuring tumor growth. Only the injection of active DCs, i.e., cells that maintained the capacity to secrete IL-12, but not exhausted DCs that had lost the ability to produce IL-12, resulted in a measurable deceleration of growth of K-Balb-NPT tumors. This anti-tumor immune response was most pronounced when using recombinant protein as an antigen source, which was evident in a prophylactic as well as in a therapeutic setting. The absence of a response to parental K-Balb tumors confirmed the antigen specificity of the anti-tumor immune response. Together these data provide evidence for the unique capacity of actively IL-12 secreting DCs to trigger effective anti-tumor immunity using exogenous tumor antigens.     

Development of a standardized protocol for reproducible generation of matured monocyte-derived dendritic cells suitable for clinical application

There is increasing interest in the generation of dendritic cells (DC) for cancer immunotherapy. In order to utilize DC in clinical trials it is necessary to have standardized, reproducible and easy to use protocols. We describe here the process development for the generation of DC as the result of investigation of culture conditions as well as consumption rates of medium and cytokines. Our studies demonstrate that highly viable DC (93 ± 2%) can be produced from CD14⁺ enriched monocytes via immunomagnetic beads in a high yield (31 ± 6%) with X-VIVO 15, 400 U ml⁻¹ GM-CSF and 2000 U ml⁻¹ IL-4 without serum and feeding. For the maturation of DC different cocktails (TNF-α, IL-1β, IL-6, PGE₂ and TNF-α, PGE₂) were compared. In both cases cells expressed typical surface molecules of mature DC and induced high proliferative responses in mixed lymphocyte reactions which led to IFN-γ producing T-lymphocytes. The data suggest that the use of this optimized, easy to use protocol results in highly mature DC. This revised version was published online in July 2006 with corrections to the Cover Date.     

Adenoviral-mediated interleukin-18 expression in mesenchymal stem cells effectively suppresses the growth of glioma in rats

Glioma is the most common primary intracranial malignant tumor. Despite advances in surgical techniques and adjuvant radio- and chemotherapies, the prognosis for patients with glioma remains poor. We have explored the effects of using genetically modified mesenchymal stem cells (MSCs) to treat malignant glioma in rats. Mesenchymal stem cells isolated from Sprague-Dawley rats can directly suppress the growth of C6 cells in vitro. MSCs transplanted intratumorally can also significantly inhibit the growth of glioma and prolong survival in C6 glioma-bearing models. MSCs producing Interleukin-18 infected by adenoviral vector inhibited glioma growth and prolonged the survival of glioma-bearing rats. Transplantation of IL-18 secreting MSCs was associated with enhanced T cell infiltration and long-term anti-tumor immunity. Thus, IL-18 may be an effective adoptive immunotherapy for malignant glioma. When used in conjunction with MSCs as targeting vehicles in vivo, IL-18 may offer a promising new treatment option for malignant glioma.     

猪白细胞介素-6在巴斯德毕氏酵母(Pichia pastoris)中的分泌表达

白细胞介素6 (Interleukin_6 ,IL_6 )是一种具有多种生物学效应的细胞因子,在疾病诊断与疫苗佐剂领域有广阔的应用前景。在本试验中,猪白细胞介素_6 (pIL_6 )的cDNA序列被克隆入甲醇酵母(Pichiapastoris)分泌表达载体pPIC9K中,并转化入P .pastorisGS115菌株。其重组菌株GS115 pPIC9K_IL6经1%甲醇诱导后,能分泌表达分子量约为2 4 5KD的重组蛋白,Westernblot确证为pIL_6。该酵母表达产物无N端糖基化修饰。用依赖IL6生长的B9细胞株检测提纯后的pIL_6 ,其生物学活性可达8×10 4 IU mg。     

Characterization of a subclone (D10S) of the D10.G4.1 helper t-cell line which proliferates to attomolar concentrations of interleukin-1 in the absence of mitogens

Most studies have shown that interleukin-1 (IL-1) acts as a helper or co-stimulator in T-lymphocyte activation and proliferation by mitogens or antigens. We describe here a stable subclone (D10S) of the murine D10.G4.1 helper T-cell which proliferates to subfemtomolar (attomolar) concentrations of IL-1 beta or alpha in the absence of mitogens. D10S cells have been maintained in culture for over two years without splenic cell feeder layers nor antigen stimulation. Detection of proliferation can be made by either uptake of tritiated thymidine at 72 h or in 48 h by a colorimetric assay which measures mitochondrial dehydrogenases; the latter assay is rapid and inexpensive. D10S cells are distinct from the parent clone D10.G4., which requires mitogens for IL-1 activity. IL-1-induced proliferation is independent of the elaboration of IL-2, IL-4, or IL-6, although these cells proliferate to these lymphokines at considerably higher concentrations when compared to IL-1. The D10S cells proliferate in direct correlation to the duration of IL-1 presence in the culture. We found no evidence that IL-1 induced more IL-1 in these cells. The subclone is highly specific for IL-1: proliferation was not observed to endotoxin, human or murine interferon-gamma (IFN gamma), tumor necrosis factor (TNF), lymphotoxin, or granulocyte-macrophage colony stimulating factor (GM-CSF). There was no suppressive effect of transforming growth factor (TGF beta). Only at high concentrations (100 ng/ml) did IL-6 induce proliferation. We conclude that this stable, feeder layer-free cell line is highly sensitive to IL-1 which acts as a direct stimulant for these cells; they are also useful for bioassays as well as the study of IL-1 receptors as described in the accompanying paper.     

Interleukin-6 does not support interleukin-2 induced generation of human lymphokine-activated killer cells

Summary The activity of lymphokine-activated killer (LAK) cells is supported by various cytokines. The objective of this study was to see if recombinant interleukin-6 (IL-6) either alone or in combination with interleukin-2 (IL-2) has any effect on the generation of LAK cells. Peripheral blood mononuclear cells of healthy donors were cultured for 4 or 6 days with both cytokines either alone or in combination. LAK activity against K562 and natural killer-resistant Daudi cells was assessed by a 4-h and an 18-h⁵¹Cr-release assay at various effector to target ratios. IL-6 alone in increasing concentrations did not induce LAK cell activity. Neither additive nor synergistic effects of IL-6 with IL-2 were observed. Immunofluorescence analysis with phycoerythrin-conjugated anti-CD56 antibody demonstrated that IL-6 could not maintain or increase the number of CD56-positive cells over a 6-day culture period. These results suggest that IL-6 does not support LAK cell generation by itself or increase LAK cell activity in combination with IL-2.     

(-)-Epigallocatechin gallate amplifies interleukin-1-stimulated interleukin-6 synthesis in osteoblast-like MC3T3-E1 cells

We previously reported that interleukin-1 (IL-1), a potent bone resorptive cytokine, stimulates the synthesis of interleukin-6 (IL-6) via activation of p44/p42 mitogen-activated protein (MAP) kinase and p38 MAP kinase in osteoblast-like MC3T3-E1 cells, and that AMP-activated protein kinase (AMPK) negatively regulates the IL-1-induced IL-6 synthesis through the inhibitor of κB (IκB)/nuclear factor-κB (NF-κB) pathway. On the other hand, it is recognized that catechin possesses a beneficial property for bone metabolism. Among them, (-)-epigallocatechin gallate (EGCG) is an abundant and major bioactive component. In the present study, we investigated the effect of EGCG on the IL-1 stimulated IL-6 synthesis in osteoblast-like MC3T3-E1 cells. EGCG significantly enhanced the IL-1-stimulated IL-6 synthesis in a dose-dependent manner in the range between 50 and 100 μM. EGCG increased the mRNA levels of IL-6 stimulated by IL-1. IL-1-induced phosphorylation of IκB and NF-κB were suppressed by EGCG. On the other hand, EGCG failed to affect the IL-1-induced phosphorylation of p44/p42 MAP kinase, p38 MAP kinase and AMPK. These results strongly suggest that EGCG enhances IL-1-stimulated IL-6 synthesis through inhibiting the AMPK-IκB/NF-κB pathway at the point between AMPK and IκB/NF-κB in osteoblasts.     

Enhancement of anti-tumor immunity specific to murine glioma by vaccination with tumor cell lysate-pulsed dendritic cells engineered to produce interleukin-12

Aim: The aim of this study was to develop an immunotherapy specific to a malignant glioma by examining the efficacy of glioma tumor-specific cytotoxic T lymphocytes (CTL) as well as the anti-tumor immunity by vaccination with dendritic cells (DC) engineered to express murine IL-12 using adenovirus-mediated gene transfer and pulsed with a GL26 glioma cell lysate (AdVIL-12/DC+GL26) was investigated. Experimentl: For measuring CTL activity, splenocytes were harvested from the mice immunized with AdVIL-12/DC+GL26 and restimulated with syngeneic GL26 for 7 days. The frequencies of antigen-specific cytokine-secreting T cell were determined with mIFN-γ ELISPOT. The cytotoxicity of CTL was assessed in a standard 51Cr-release assay. For the protective study in the subcutaneous tumor model, the mice were vaccinated subcutaneously (s.c) with 1×10⁶ AdVIL-12/DC+GL26 in the right flanks on day −21, −14 and −7. On day 7, the mice were challenged with 1×10⁶ GL26 tumor cells in the shaved left flank. For a protective study in the intracranial tumor model, the mice were vaccinated with 1×10⁶ AdVIL-12/DC+GL26 s.c in the right flanks on days −21, −14 and −7. Fresh 1×10⁴ GL26 cells were inoculated into the brain on day 0. To prove a therapeutic benefit in established tumors, subcutaneous or intracranial GL26 tumor-bearing mice were vaccinated s.c with 1×10⁶ AdVIL-12/DC+GL26 on day 5, 12 and 19 after tumor cell inoculation. Results: Splenocytes from the mice vaccinated with the AdVIL-12/DC+GL26 showed enhanced induction of tumor-specific CTL and increased numbers of IFN-γ: secreting T cells by ELISPOT. Moreover, vaccination of AdVIL-12/DC+GL26 enhanced the induction of anti-tumor immunity in both the subcutaneous and intracranial tumor models. Conclusions: These preclinical model results suggest that DC engineered to express IL-12 and pulsed with a tumor lysate could be used in a possible immunotherapeutic strategy for malignant glioma.Korea Research Foundation Grant (KRF-2004-005-E00001).     

Regenerating gene I regulates interleukin-6 production in squamous esophageal cancer cells

Regenerating gene (REG) I plays important roles in cancer cell biology. The purpose of this study was to determine whether REG I affects cytokine production in cancer cells. We transfected TE-5 and TE-9 squamous esophageal cancer cells with REG Iα and Iβ and examined its effects on cytokine expression. We found that transfecting TE-5 and TE-9 cells with REG I Iα and Iβ led to significantly increased expression of interleukin (IL)-6 mRNA and protein, but it had little or no effect on expression of IL-2, IL-4, IL-5, IL-10, IL-12, IL-13, IL-17A, interferon-γ, tumor necrosis factor-α, granulocyte-colony stimulating factor or transforming growth factor-β1. The elevated IL-6 expression seen in REG Iα transfectants was silenced by small interfering RNA-mediated knockdown. These finding suggest that REG I may act through IL-6 to exert effects on squamous esophageal cancer cell biology.     

Inhibition of interleukin-6 release and T-cell proliferation by synthetic mirror pseudo cord factor analogues in human peripheral blood mononuclear cells

Abstract The effects of synthetic alkyl ((alkyl 6-deoxy-a- d - gluco -heptopyranosyluronate) 6-deoxy-a- D -gluco-heptopyranoside) uronates, a novel type of mirror pseudo cord factor, on the in vitro modulation of interleukin-6 production and T-cell proliferation in human peripheral blood mononuclear cells, were investigated. Synthetic mirror pseudo cord factors with alkyl chains ranging from C₁₆ to C₁₈ have very weak interleukin-6-inducing capacities and lack mitogenic activities for T-cell proliferation. However, they could inhibit IL-6 release induced by sonicated Bacillus Calmette-Guérin (S-BCG), bacterial endotoxin, and phytohaemagglutinin in a dose-dependent manner. Inhibition was observed not only with mononuclear cells but also with purified monocytes. Furthermore, these synthetic compounds could suppress T-lymphocyte proliferation stimulated by sonicated Mycobacterium tuberculosis H37Rv (S-H37Rv) antigens, S-BCG antigens, as well as by recombinant 65 kDa mycobacterial heat-shock protein. In contrast, these compounds failed to inhibit the phytohaemagglutinin-induced T-cell proliferation. We conclude that the inhibition of cytokine release and T-cell proliferation by synthetic mirror pseudo cord factors was due to direct blocking of the function and/or activity of monocytes or antigen-presenting cells.     

The roles of interleukin-1 and interleukin-1 receptor antagonist in antigen-specific immune responses

Despite evidence that interleukin (IL)-1 promotes the proliferation of some T helper 2 (Th2) cell clones in vitro, the physiological role of IL-1 in the regulation of antigen-specific immune responses remains undefined. Using a liposome-DNA delivery system, we transiently expressed IL-1 receptor antagonist (IL-1Ra) to suppress IL-1 functions at the site of the antigen-specific primary immune response. Our data indicate, for the first time, that IL-1Ra downregulates antigen-specific IL-4 and IgE responses, with concomitant enhancement of interferon- and IgG2a responses in vivo. In addition, IL-1 can promote Th2 development in an IL-4-independent manner in vitro. Thus, the balance between endogenous IL-1 and IL-1Ra during the primary immune response can be an important factor in determining the antigen-specific effector function of T cells.     

The rational designed antagonist derived from the complex structure of interleukin-6 and its receptor affectively blocking interleukin-6 might be a promising treatment in multiple myeloma

Human interleukin-6 is involved in the maintenance and progression of several diseases such as multiple myeloma (MM), rheumatoid arthritis, or osteoporosis. Our previous work demonstrated that an interleukin-6 antagonist peptide (named PT) possessed potential bioactivity to antagonize the function of hIL-6 and could efficiently induce the growth arrest and apoptosis of XG-7 and M1 cells in a dose-dependent manner. In this study, the theoretical interaction of the peptide PT with its receptor was analyzed further more with molecular docking and molecular dynamics methods. The theoretical studies showed that PT possessed very high affinity to interleukin-6R and offered a practical means of imposing long-term blockade of interleukin-6 activity in vivo. According to the theoretical results, the biological evaluation of PT was researched on two different cells models with more sensitive approaches: (1) The antagonist activity of PT was studied on the interleukin-6 dependent MM cells (XG-7) cultured with interleukin-6. In the other interleukin-6 dependent MM cells (SKO-007), they survived themselves by auto/paracrine without the exogenous interleukin-6, and also could be antagonized by PT. The therapeutic value of PT only limited on the interleukin-6 dependent category in MM. (2) Myeloid leukemia M1 cells were induced for growth arrest and apoptosis in response to interleukin-6. The results supported our previous findings and showed that PT could be evaluated by protecting the cells from interleukin-6 induced apoptosis. In conclusion, PT could induce interleukin-6-dependent XG-7 and SKO-007 cells to apoptosis while inhibit interleukin-6-stimulated apoptosis in M1 cells.     

Serum and urine levels of interleukin-6 and interleukin-8 in children with acute pyelonephritis

Urinary tract infection (UTI) is a common clinical disorder in younger infants and children and may result in permanent renal damage. The inflammatory cytokines interleukin (IL)-6 and IL-8 play an important role in response to bacterial infection. This prospective study investigated the association between serum and urine IL-6 and IL-8 levels and acute pyelonephritis confirmed by (99m)Tc-dimercaptosuccinic acid (DMSA) scan. A total of 78 children aged 1-121 months with a diagnosis of first-time febrile UTI were included. The following inflammatory markers were assessed: fever; white blood cells count (WBC); C-reactive protein (CRP); and serum and urine IL-6 and IL-8. The patients were divided into the acute pyelonephritis group (n=42) and the lower UTI group (n=36) according to the results of DMSA scan. Fever, WBC and CRP levels were significantly higher in children with acute pyelonephritis than in those with lower UTI (all p <0.001). Significantly, higher initial serum and urine IL-6 and IL-8 levels were found in children with acute pyelonephritis than in those with lower UTI (all p <0.001). Serum and urine IL-6 in children with acute pyelonephritis were positively correlated with fever, CRP and leucocyturia. These results indicate that both serum and urine IL-6 and IL-8 levels, particularly IL-6, are useful diagnostic tools for early recognition of acute pyelonephritis in febrile children.     

Associations of interleukin-6 with interleukin-1beta, interleukin-8 and macrophage inflammatory protein-1beta in midlife women

Objective: The aim of the present study was to determine the associations of interleukin (IL)-6 with other cytokines and chemokines and to compare these associations in peri- and postmenopausal women. Methods: Ninety-nine perimenopausal and 92 postmenopausal women were enrolled in this study. Serum concentrations of IL-6, IL-1β, IL-2, IL-4, IL-5, IL-7, IL-8, IL-10, IL-12, IL-13, IL-17, tumor necrosis factor (TNF)-α, interferon γ, granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage (GM)-CSF, macrophage inflammatory protein (MIP)-1β and monocyte chemotactic protein (MCP)-1 were measured simultaneously using a multiplexed cytokine assay. Results: Among the 17 cytokines, IL-6, IL-1β, IL-5, IL-7, IL-8, IL-10, MCP-1 and MIP-1β were detected in serum in more than 50% of the women. Serum levels of IL-4 and MCP-1 in postmenopausal women were significantly higher than those in perimenopausal women. Serum IL-6 concentrations showed significant and positive correlations with serum concentrations of IL-1β, IL-8, MIP-1β, IL-7 and MCP-1 in women regardless of menopausal status, and these correlations were still significant after adjustment for age and body mass index. Conclusion: Serum IL-6 concentration was found to be closely associated with serum concentrations of IL-1β, IL-8, MIP-1β, IL-7 and MCP-1 in women regardless of menopausal status, suggesting that these cytokines act in concert with the progression of several symptoms and various diseases.     

Expression and function of interleukin-6 in epithelial cells

Epithelial cells both produce and are affected by interleukin-6 (IL-6). Experiments with an adenocarcinoma-derived cell line (HeLa) reveal that activation of the transfected human IL-6 promoter occurs largely through two partially overlapping second messenger (cAMP, phorbol ester)- and cytokine (IL-1, TNF, serum)-responsive enhancer elements (MRE 1, -173 to -151 and MRE II, -158 to -145). MRE I contains the typical GACGTCA cAMP and phorbol ester-responsive (CRE-TRE) motif, whereas MRE II defines a new CRE/TRE motif that contains an imperfect dyad repeat. The mechanism of dexamethasone-mediated repression of IL-6 gene expression in epithelial cells involves occlusion of the entire MRE enhancer region and of the core-promoter elements (TATA-box and RNA start site) by ligand-activated glucocorticoid receptor. Enhanced levels of IL-6 expression are observed in many solid tumors and in the hyperproliferative (and glucocorticoid-suppressible) lesions of psoriasis. In cell culture, IL-6 enhances, inhibits, or has no effect on the proliferation of epithelial cells depending upon the cell-type examined. IL-6 enhances proliferation of keratinocytes but inhibits that of breast carcinoma cell lines ZR-75-1 and T-47D. In these breast carcinoma cells, IL-6 elicits a major change in cell phenotype which is characterized by a fibroblastoid morphology, enhanced motility, increased cell-cell separation, and decreased adherens type junctions (desmosomes and focal adhesions). The new data identify IL-6 as a regulator of epithelial cell growth and of cell-cell association.     

Differential involvement of central and peripheral norepinephrine in the central lipopolysaccharide-induced interleukin-6 responses in mice

Intracerebroventricular injection of lipopolysaccharide (LPS) induces a marked increase in circulating interleukin (IL)-6 levels and in IL-6 mRNA expression in brain and peripheral organs. Recently, it was reported that intraperitoneal administration of alpha-adrenoceptor antagonists inhibits centrally injected LPS-induced increases in plasma IL-6 levels, suggesting the involvement of the norepinephrine (NE) system in the central LPS-induced IL-6 response. However, the localization (either central or peripheral) of NE involvement in the central LPS-induced IL-6 response has not been characterized. In the present study, mice were pretreated with 6-hydroxydopamine (6-OHDA) administered intracerebroventricularly or intraperitoneally to deplete central or peripheral stores of NE, respectively. Intracerebroventricular LPS (50 ng/mouse) markedly increased plasma IL-6 levels and IL-6 mRNA expression in choroid plexus, hypothalamus, pituitary, adrenals, heart, liver, spleen, and lymph nodes, but with minimal effect in lung, kidney, and testis, as revealed by RT-PCR. Pretreatment with intracerebroventricular 6-OHDA (50 microg/mouse) decreased the LPS-induced plasma IL-6 levels by 39% and the LPS-induced IL-6 mRNA expression in liver, spleen, and lymph nodes, but not in choroid plexus, hypothalamus, pituitary, adrenals, and heart. Pretreatment with intraperitoneal 6-OHDA (100 mg/kg) decreased the LPS-induced plasma IL-6 levels by 36% and the LPS-induced IL-6 mRNA expression in all the peripheral organs displaying increased IL-6 mRNA. Central LPS-induced increase in plasma corticosterone levels was decreased slightly by central but not by peripheral NE depletion. These results suggest that central NE and peripheral NE are differentially involved in the central LPS-induced IL-6 mRNA expression in peripheral organs.     

The expression of interleukin-6 by a rat macrophage-derived cell line

A stable rat macrophage-derived cell line (RMSV1) was established by transformation of primary peritoneal exudate cells with the SV40 virus. The RMSV1 cell line was used as a model to study the regulation of the interleukin-6 (IL6) gene expression in rate macrophages with respect to lipopolysaccharides (LPS), interleukin-1 (IL1) and glucocorticoids. The IL6 mRNA level in RMSV1 cell lines was induced 20-fold within 4 h by LPS, whereas IL1 had no effect. The glucocorticoids were able to inhibit completely the induction of the IL6 mRNA synthesis by LPS, indicating the negative regulation of the IL6 gene expression by glucocorticoids.     

Induction of a T helper cell response against the tumor-associated antigen HER2 using monocyte-derived dendritic cells

Tumor-reactive CD4⁺ T helper (Th) cells play a criticalrole in antitumor immunity, due to their ability to induceCD8⁺ T cell-mediated cytotoxic activity and humoralresponse. This study focuses on the in vitro generationand expansion of Th cells specific for the tumor-associatedantigen `human epidermal growth factor receptor-2' (HER2). Aprotocol for efficient HER2 presentation was developed usingautologous monocyte-derived dendritic cells (DC) as antigenpresenting cells (APC) and purified HER2 protein as antigensource. Our data suggest that DC pulsed with recombinantprotein of the extracellular domain (ECD) of HER2 (ECD/HER2)induce an ECD/HER2-specific Th cell response. This finding mayfacilitate the development of immunotherapy regimens withoutrequiring defined immunogenic epitopes of the antigen.