Cell Stimulatory Factor Research Articles

Co-immunization with FLT3-L, a dendritic cell growth and stimulating factor, enhances humoral and cellular immune responses after genetic immunization against hepatitis C virus in mice: Jens C Encke, Jomo Bernardin, University of Heidelberg, Heidelberg Germany; Raymond Buidoso, University of Cambridge, Cambridge Uk; Wolfgang Stremmel, University of Heidelberg, Heidelberg Germany

Co-immunization with FLT3-L, a dendritic cell growth and stimulating factor, enhances humoral and cellular immune responses after genetic immunization against hepatitis C virus in mice: Jens C Encke, Jomo Bernardin, University of Heidelberg, Heidelberg Germany; Raymond Buidoso, University of Cambridge, Cambridge Uk; Wolfgang Stremmel, University of Heidelberg, Heidelberg Germany

DENDRITIC CELL BASED VACCINES: PROGRESS IN IMMUNOTHERAPY STUDIES FOR PROSTATE CANCER

No effective treatment is currently available for metastatic prostate cancer. Dendritic cell (DC) based cancer vaccine research has emerged from the laboratories to human clinical trials. We describe progress in the development of DC based prostate cancer vaccine. The literature was reviewed for major contributions to a growing number of studies that demonstrate the potential of DC based immunotherapeutics for prostate cancer. Background topics relating to DC based immunotherapy theory and practice are also addressed. DCs have been recognized as the most efficient antigen presenting cells that have the capacity to initiate naive T cell response in vitro and in vivo. During their differentiation and maturation pathways, dendritic cells can efficiently capture, process and present antigens for T cell activation. These characteristics make DC an attractive choice as the cellular adjuvant for cancer vaccines. Advances in DC generation, loading, and maturation methodologies have made it possible to generate clinical grade vaccines for various human trials. More than 100 DC vaccine trials, including 7 studies of patients with advanced prostate cancer have been reported to date. These vaccines were generally well tolerated with no significant adverse toxicity reported. Clinical responders have been identified in these studies. The new prospects opened by DC based vaccines for prostate cancer are fascinating. When compared to conventional treatments, DC vaccinations have few side effects. Improvements in patient selection, vaccine delivery strategies, immune monitoring and vaccine manufacturing will be crucial in moving DC based prostate cancer vaccines closer to the clinics.

The C-terminal peptide of thrombospondin-4 stimulates erythroid cell proliferation

Erythropoietin (EPO) stimulates the production of small erythroid cell stimulating factors (molecular weight <5kDa) in cultures of bone marrow endothelial cells. We identified a fragment of thrombospondin-4 (TSP-4) as an EPO-stimulated protein in endothelial cell lysates. Pre-incubation of the low molecular weight fractions from supernatants of EPO-treated umbilical cord endothelial cells (HUVEC) with antibodies against the C-terminal residues of TSP-1,2 and TSP-4 decreased the erythroid cell stimulating activity. The C-terminal TSP-1 section corresponding to a molecular weight lower than 6kDa has the integrin-associated protein binding motif VVM. The corresponding TSP-4 fragment, lacking the three residue sequence VVM, has a distinctive acidic peptide comprising the last 21 amino acids (C21) with the characteristics of an amphipathic helix. C21 stimulated thymidine incorporation into bovine erythroid cells, increased cell numbers in cultures of cord blood CD36+ erythroid precursors and skin fibroblasts, and decreased HUVEC proliferation. SC21, a homologous peptide of identical amino acid composition but with interchanged residues, was non-amphipathic and had no erythroid cell stimulating activity.

Discussion

Discussion

Functional significance of novel neurotrophin-1/B cell-stimulating factor-3 (cardiotrophin-like cytokine) for human myeloma cell growth and survival.

Cytokines of the gp130 family, particularly interleukin 6 (IL-6), play a central role in the growth and survival of malignant plasma cells. Recently, novel neurotrophin-1 (NNT-1)/B cell-stimulating factor-3 (BSF-3), also reported as cardiotrophin-like cytokine (CLC), was identified as a cytokine belonging to the gp130 family. BSF-3, similar to IL-6, exerts regulatory effects on normal B cell functions, but its functional significance in haematological malignancies has not been defined. The purpose of this study was to evaluate the biological effects and signalling pathways that are induced by BSF-3 in malignant plasma cells. Recombinant human BSF-3 was found to have growth stimulatory activity on plasmacytoma cell lines and primary tumour cells. In addition, BSF-3 was able to protect from Dexamethasone (Dex)-induced apoptosis. BSF-3 stimulated cell growth could not be inhibited by neutralizing anti-IL-6 or anti-IL-6 receptor antibodies, but was abrogated by anti-gp130 antibodies. In INA-6.Tu11 cells, a subline of the IL-6-dependent human plasma cell line INA-6 expressing gp130 and the receptor for leukaemia inhibitory factor (LIF), stimulation with BSF-3 induced tyrosine phosphorylation of signal transducer and activator of transcription 3 (STAT3). AG490, an inhibitor of Janus kinases, decreased BSF-3 induced cell growth in a dose-dependent manner. This correlated with a reduction of STAT3 phosphorylation levels, while p44/42 mitogen-activated protein kinase (MAPK) phosphorylation was not affected. In conclusion, BSF-3 is a novel myeloma growth and survival factor with a potential role in the pathophysiology of the disease.

Expression of novel neurotrophin-1/B-cell stimulating factor-3 (NNT-1/BSF-3) in murine pituitary folliculostellate TtT/GF cells: pituitary adenylate cyclase-activating polypeptide and vasoactive intestinal peptide-induced stimulation of NNT-1/BSF-3 is mediated by protein kinase A, protein kinase C, and extracellular-signal-regulated kinase1/2 pathways.

Novel neurotrophin-1/B cell stimulating factor-3 (NNT-1/BSF-3) is a gp130 cytokine potently stimulating corticotroph proopiomelanocortin gene expression and ACTH secretion by a Janus kinase-signal transducer and activator of transcription (JAK-STAT)-dependent mechanism. In the current study, we examined the regulation of NNT-1/BSF-3 mRNA expression in murine pituitary folliculostellate TtT/GF cells using Northern blot technique. A 5- to 9-fold and a 4- to 7-fold induction in NNT-1/BSF-3 mRNA expression was observed between 2 and 6 h stimulation with the protein kinase C (PKC) stimulus phorbol-12-myristate-13-acetate (100 nm) and the protein kinase A (PKA) stimulus Bu(2)cAMP (5 mm), respectively. Pituitary adenylate cyclase-activating polypeptide (PACAP-38, 50 nm) and vasoactive intestinal peptide (VIP, 50 nm) also stimulated NNT-1/BSF-3 mRNA expression 5- to 9-fold between 2 and 6 h. Preincubation with PKC and PKA inhibitors such as H-7 (20 microm), GF109203X (50 microm), and H-89 (50 microm) decreased the stimulatory effects of PACAP and VIP. Both PACAP-38 and VIP also rapidly induced ERK1/2 phosphorylation and their stimulatory effect on NNT-1/BSF-3 mRNA expression was reduced by the MAPK kinase/ERK kinase (MEK) inhibitor U0126 (10 microm). Dexamethasone (10(-7) m) was a potent inhibitor of phorbol-12-myristate-13-acetate-induced NNT-1/BSF-3 expression. RT-PCR analysis demonstrated TtT/GF cells to express the short and the hop variant but not the hip variant of the PACAP-1 receptor (PAC1-R). In addition, TtT/GF cells express the VIP/PACAP-2 receptor (VPAC2-R). In summary, NNT-1/BSF-3 is expressed in pituitary folliculostellate TtT/GF cells and induced by PKC-, PKA-, and ERK1/2-dependent mechanisms. The novel gp130 cytokine NNT-1/BSF-3 derived from folliculostellate cells might act as a paracrine neuroimmunoendocrine modulator of pituitary corticotroph function.

Interleukin 6 receptor as a target for the treatment of rheumatoid arthritis

Chronic synovial inflammation and joint damage are cardinal features of rheumatoid arthritis (RA). Although the precise cause remains unknown, cytokines have a major pathogenic role. The therapeutic benefit of antagonists...

Novel neurotrophin-1/B cell-stimulating factor-3 (cardiotrophin-like cytokine) stimulates corticotroph function via a signal transducer and activator of transcription-dependent mechanism negatively regulated by suppressor of cytokine signaling-3.

Novel neurotrophin-1/B cell-stimulating factor-3 (NNT-1/BSF-3) is a recently cloned gp130 cytokine, acting through the tripartite ciliary neurotrophic factor receptor (CNTFR) alpha/leukemia inhibitory factor receptor (LIFR)/gp130 receptor complex. The aim of the current study was to investigate the role of NNT-1/BSF-3 in corticotroph cell function and further characterize NNT-1/BSF-3 signaling pathways. Using RT-PCR, expression of ciliary neurotrophic factor receptor alpha, leukemia inhibitory factor receptor, and gp130 could be demonstrated in mRNA derived from murine corticotroph AtT-20 cells and murine pituitary tissue. Incubation of AtT-20 cells with 10 ng/ml recombinant human NNT-1/BSF-3 rapidly induced tyrosine-phosphorylation of signal transducer and activator of transcription (STAT)3 and STAT1 at 5 and 10 min. Proopiomelanocortin promoter activity and suppressor of cytokine signaling (SOCS)-3 promoter activity were significantly stimulated by NNT-1/BSF-3 4.0 +/- 0.3- and 5.9 +/- 0.2-fold, respectively. In comparison with untreated control, NNT-1/BSF-3 significantly stimulated ACTH secretion at 24 and 48 h 1.7 +/- 0.2-fold and 1.5 +/- 0.1-fold above baseline. In comparison with mock-transfected cells, stable overexpression of SOCS-3 in AtT-20 cells abolished NNT-1/BSF-3-induced STAT1 and STAT3 phosphorylation and almost completely inhibited STAT-dependent proopiomelanocortin promoter and SOCS-3 promoter activities. In addition, NNT-1/BSF-3-induced ACTH secretion at 48 h was significantly attenuated by SOCS-3 overexpression. In summary, we have shown that NNT-1/BSF-3 is a modulator of corticotroph cell function, which is negatively regulated by SOCS-3. Our data indicate that the activation of the Jak-STAT cascade is essential for corticotroph NNT-1/BSF-3 signaling. Further studies will have to investigate the possible in vivo role of NNT-1/BSF-3 as a neuroimmunoendocrine modulator of hypothalamus-pituitary-adrenal axis stress response.

Dendritic cells for NK/LAK activation: rationale for multicellular immunotherapy in neuroblastoma patients

Natural killer (NK)/lymphokine-activated killer (LAK) cell-based immunotherapy could be beneficial against major histocompatibility complex class I-negative tumor residual disease such as neuroblastoma (NB), provided that interleukin 2 (IL-2) or surrogate nontoxic NK cell stimulatory factors could sustain NK cell activation and survival in vivo. Here we show that human monocyte-derived dendritic cells (MD-DCs) promote potent NK/LAK effector functions and long-term survival, circumventing the need for IL-2. This study demonstrates (1) the feasibility of differentiating granulocyte colony-stimulating factor-mobilized hematopoietic peripheral blood stem cells (PBSCs) into high numbers of functional MD-DCs and NK/LAK cells in a series of 12 children with stage 4 neuroblastoma (NB); (2) potent DC-mediated NK cell activation in autologous settings; (3) the reciprocal capacity of NK/LAK cells to turn immature DCs into maturing cells electively capable of triggering NK cell functions; and (4) the unique capacity of maturing DCs to sustain NK cell survival, superior to that achieved in IL-2. These data show a reciprocal interaction between DCs and NK/LAK cells, leading to the amplification of NK cell effector functions, and support the implementation of DC/NK cell-based immunotherapy for purging the graft and/or controlling minimal residual disease after autologous stem cell transplantation.

Changes in cytokine expression in peripheral leukocytes, detected by microarray analysis, in the secretory vs proliferative phase of the menstrual cycle

Objective: Many autoimmune disorders have recognized clinical changes in pregnancy and the menstrual cycle. However the mechanisms by which hormones, menstrual cycle changes and pregnancy affect the immune system in unknown. The complexity of the immune system and abundance of immune markers necessitate global analysis. Herein, we describe high density oligonucleotide microarray profiling of peripheral blood leukocytes from the proliferative and secretory phases of the menstrual cycle. Design: Microarray analysis of peripheral blood leukocytes from the proliferative and secretory phases of the menstrual cycle. Materials/Methods: Peripheral blood was obtained from healthy female volunteers (n=5) after informed consent. Subjects were 25–34 yo with menstrual cycles of 28–30 days. Paired samples were collected from subjects in nonconception cycles in the late proliferative (cycle day 10–12) and midsecretory phase (day 20–24). Total RNA was extracted using the Paxgene Blood RNA Validation Kit. cDNA was synthesized from total RNA then biotinylated cRNAs were generated by in vitro transcription. Fragmented cRNAs were hybridized on Affymetrix HU95A microarrays, containing 12,686 human genes and ESTs. The data were analyzed with GeneChip Analysis Suite v5.0, GeneSpring v4.2& MS Excel. Results from each phase were normalized and gene expression was compared. Non-parametric testing was applied to genes showing 1.5 fold changes between the proliferative and secretory phases with a p <0.05 for statistical significance. Results: 10 cc of blood yielded 10–15 g of leukocyte RNA. 17 g of high purity, labeled cRNA was used for hybridization. 314 genes were found to be significantly up-regulated in the secretory phase compared to proliferative, including NKG2F, complement receptor C1r, fibroblast growth factor, monocyte chemotactic protein-2, C-C chemokine receptor-4, platelet derived growth factor receptor and natural killer cell stimulatory factor (IL 12). 362 genes were significantly down-regulated in the secretory phase, such as allograft inflammatory factor-1(AIF-1), pre-B cell enhancing factor (PBEF), GM-CSF receptor beta chain, leukocyte immunoglobulin-like receptor-3(LIR-3), interferon regulatory factor 1, lymphocyte activation antigen CD30, and pT49. Conclusions: We have shown significant changes in the expression of cytokines and their receptors in the menstrual cycle. While validation of these findings and further study are needed to determine their clinical significance, immune cells and their effector cytokines are actively involved in the process of implantation and maternal tolerance to a developing fetus. Peripheral changes in immune cells have been previously described in patients with recurrent spontaneous abortion and unexplained infertility. This study lays foundation for further deliniation of steroid hormone control of immune function and dysfunction in women. Supported by: NIH Training grant HD07493 and Women’s Health at Stanford.

Regulatory effects of novel neurotrophin-1/b cell-stimulating factor-3 (cardiotrophin-like cytokine) on B cell function.

We describe regulatory effects that a novel neurotrophin-1/B cell-stimulating factor-3 (NNT-1/BSF-3; also reported as cardiotrophin-like cytokine) has on B cell function. NNT-1/BSF-3 stimulates B cell proliferation and Ig production in vitro. NNT-1/BSF-3-transgenic mice, engineered to express NNT-1/BSF-3 in the liver under control of the apolipoprotein E promoter, show B cell hyperplasia with particular expansion of the mature follicular B cell subset in the spleen and the prominent presence of plasma cells. NNT-1/BSF-3-transgenic mice show high serum levels of IgM, IgE, IgG2b, IgG3, anti-dsDNA Abs, and serum amyloid A. NNT-1/BSF-3-transgenic mice also show non-amyloid mesangial deposits that contain IgM, IgG, and C3 and are characterized by a distinctive ultrastructure similar to that of immunotactoid glomerulopathy. NNT-1/BSF-3-transgenic mice produce high amounts of Ag-specific IgM, IgA, and IgE and low amounts of IgG2a and IgG3. Normal mice treated with NNT-1/BSF-3 also produce high amounts of Ag-specific IgE. NNT-1/BSF-3 regulates immunity by stimulating B cell function and Ab production, with preference for Th2 over Th1 Ig types.

Activation of B lymphocytes by GLIS, a bioactive proteoglycan from Ganoderma lucidum

A bioactive fraction (GLIS) was isolated from the fruiting body of the fungus Ganoderma lucidum using successive chromatographic steps. GLIS is a proteoglycan and has a carbohydrate: protein ratio of 11.5 : 1. The carbohydrate portion is composed of seven different monosaccharides, predominantly D-glucose, D-galactose and D-mannose in the molar ratio of 3.0 : 1 : 1. GLIS stimulated the proliferation of mouse spleen lymphocytes, resulting in a three to four-fold increase in the percentage of B cells. GLIS also activated mouse spleen lymphocytes, and most of the activated cells were B cells. The B cells were enlarged, expressed CD71 and CD25 on the cell surface, and showed an increase in the secretion of immunoglobulin. Lymphocytes also showed a slightly increased production of IL-2, whereas the secretion of IL-4 was not influenced by GLIS. Furthermore, GLIS did not influence the intracellular Ca 2+ concentration of lymphocytes, but it enhanced the expression of protein kinase C α and protein kinase C γ in B cells. According to our results GLIS is a new B cell-stimulating factor.

Cardiotrophin-like cytokine induces astrocyte differentiation of fetal neuroepithelial cells via activation of STAT3.

Cardiotrophin-like cytokine (CLC), also known as novel neurotrophin-1/B cell stimulating factor-3 (NNT-1/BSF-3), is a recently identified member of the interleukin (IL)-6 family of cytokines that share gp130 as a signal-transducing receptor component. In this study, we demonstrate that CLC is expressed in fetal mouse neuroepithelial cells and has a potential to induce their astrocyte differentiation in a synergistic manner with bone-morphogenetic protein (BMP)-2, which is also expressed in the fetal mouse brain. CLC-stimulation led to promoter activation of the gene for an astrocyte marker, glial fibrillary acidic protein (GFAP), which was clearly inhibited by expression of a dominant negative form of a transcription factor, STAT3, or by introduction of a mutation in a single STAT3-binding site in the promoter, suggesting a critical role of STAT3 in the CLC-induced GFAP transcription. These results suggest that CLC plays a role in astrocyte differentiation via STAT3 activation within the developing brain.

CO-immunization with FLT3-L, a dendritic cell growth and stimulating factor, enhances humoral and cellular immune responses after genetic immunization against hepatitis C virus in mice

CO-immunization with FLT3-L, a dendritic cell growth and stimulating factor, enhances humoral and cellular immune responses after genetic immunization against hepatitis C virus in mice

Interleukin-12 augments cytolytic activity of peripheral blood mononuclear cells against autologous lung cancer cells in combination with IL-2

The majority of patients with advanced lung cancer die within a few years. Accordingly, new therapeutic modalities need to be developed. Interleukin (IL)-12 was previously known as natural killer (NK) cell stimulatory factor or cytotoxic lymphocyte maturation factor. By virtue of its effects on T cells and NK cells, IL-12 seems to be one of the key cytokines that regulates cell-mediated anti tumor immune responses. Recently, there has been a substantial interest in the potential applications of IL-12 in the treatment of lung cancer. However, there have been no reports about the effect of IL-12 on peripheral blood mononuclear cells (PBMCs) obtained from lung cancer patients in an autologous setting. In this study, we examined the cytotoxicity of PBMC activated by IL-2, IL-12 or both against K562 or autologous lung cancer cells. In contrast to the effect of IL-2 on NK activity, IL-12 alone augmented NK activity against K562 cells, but not against autologous lung cancer cells. IL-12 augmented the IL-2 mediated cytotoxicity of PBMC against both K562 and autologous lung cancer cells. In the absence of IL-2, IL-12 alone cannot induce an autologous anti-tumor effect in vivo. In summary, our results clearly demonstrated that IL-12 can augment the cytolytic activity of PBMC against K562 and autologous lung cancer cells when combined with IL-2, although, IL-12 alone was unable to induce a marked increase in the cytotoxicity against autologous lung cancer cells. These results suggest that an administration of IL-12 in combination with IL-2 may be a useful therapeutic option for solid tumors.

Activity of a Humanized Monoclonal Antibody (Bevacizumab) Against Vascular Endothelial Growth Factor for Metastatic Breast Cancer

• One of the most important stimulators of angiogenesis is vascular endothelial growth factor (VEGF), also known as vascular permeability factor.1,2 VEGF has a number of biologic activities related to neovascularization, including promotion of endothelial cell viability (through induction of Bcl-2) as well as mitogenesis (phosphatidylinositol 3-kinase and mitogen-activated protein kinase pathways); enhancing chemotaxis of macrophages that produce endothelial cell stimulatory factors as well as VEGF; increased expression of collagenase, tissue-type, and urokinase-type plasminogen activators; and increased vascular permeability and vasodilation. Moreover, preclinical evidence suggests that VEGF is able to protect cells from the cytotoxicity of chemotherapy agents such as docetaxel.

Generation and characterization of a neutralizing monoclonal antibody against erythroid cell stimulating factor.

Erythroid cell stimulating factor (ESF) is present in mouse serum and has been reported to function in concert with erythropoietin (EPO) in the formation of erythroid cells in in vitro culture systems. We report here the generation and characterization of a monoclonal antibody (MAb) directed against ESF, with potent anti-ESF-neutralizing activity. A hybridoma-producing MAb to ESF was selected following enzyme-linked immunosorbent assay (ELISA)-based screening of 270 colonies obtained from a fusion of immunized mouse splenocytes with NS1 myeloma cells. Western blot analyses of mouse serum using this antibody specifically detected a single protein (approximate molecular weight of 60 kDa and 120 kDa, under reducing and nonreducing conditions, respectively) corresponding to ESF, with no reactivity to EPO. Furthermore, this MAb demonstrated reactivity to a protein similar in molecular mass, across species, showing reactivity in sera obtained from human, horse, goat, guinea pig, rabbit, and rat. Immuno-chemical characterization demonstrated this antibody to be of IgG3 isotype, bearing kappa light chains. Injection of this monoclonal anti-ESF antibody to exhypoxic polycythemic mice at 6 and 24 h after EPO injection significantly reduced 59Fe incorporation into red blood cells, demonstrating its ability to neutralize in vivo erythropoiesis in our mouse model system. Thus, this novel erythroid cell-specific MAb will be an invaluable tool for further delineating the physiological role of ESF in in vivo erythropoiesis.

AUTOCRINE IL-6 PRODUCTION BY HUMAN TRANSITIONAL CARCINOMA CELLS UPREGULATES EXPRESSION OF THE α5β1 FIBRONECTIN RECEPTOR

Purpose: Studies have demonstrated elevated expression and secretion of IL-6 by transitional cell carcinomas (TCC) following bacillus Calmette-Guerin (BCG) therapy. At present, the role of IL-6 on the biology of TCC is poorly understood. This study evaluated the influence of IL-6 expression on a critical variable regulating BCG-tumor interaction, the tumor expression of α5β1 integrin. Materials and Methods: A human TCC cell line (253J) was transfected with an expression vector containing the full-length IL-6 cDNA sequence. Overexpression of IL-6 mRNA and protein was confirmed by Northern analysis and ELISA, respectively. Clones found to overexpress IL-6 were then assayed for α5β1 expression using Northern analysis and flow cytometry. The effect of alterations in α5β1 expression on tumor adherence to fibronectin (FN), and BCG adherence to tumor cells was determined using specific adherence assays. Results: mRNAs for both the α5 and β1 subunits of the FN receptor were increased an average of 9.4 fold and 125.7 fold respectively in the IL-6 overexpressing transfectants relative to the parental 253J cells. Increased mRNA of α5 and β1 was associated with increased cell surface expression of both proteins. Increased protein expression resulted in greater FN substrate binding affinity and increased adherence of BCG to tumor cells. Conclusions: Autocrine expression of IL-6 upregulates the expression of FN receptor subunits in TCC. Increased α5β1 expression increases cellular adherence to FN, and BCG adherence to tumor cells. These results suggest a role for IL-6 in mediating the antitumor activity of BCG by influencing BCG's adherence to TCC.

Effect of brief maximal exercise on circulating levels of interleukin-12.

Interleukin-12 (IL-12) is a cytokine that was originally identified as natural killer cell stimulatory factor. It induces the activity of T-helper 1 (Th1) cells and exhibits strong anti-tumor activity. In this study, we studied the effects of brief anaerobic maximal exercise on circulating levels of IL-12. Six healthy males [mean (SD) 25.2 (2.6) years] performed a modified Wingate test exercise (resistance 0.075 kg/kg of body mass). The exercise consisted of five bouts of maximal cycling for 10 s, with rest intervals of 50 s between them. Blood samples were taken before, immediately after, 30 min after, 60 min after and 120 min after the exercise. Plasma concentrations of IL-12 were measured using an enzyme-linked immunosorbent assay. Data were corrected for hemoglobin and hematocrit measurements. Plasma concentrations of IL-12 averaged [mean (SD)] 234.2 (40.9) pg/ml before, 305.2 (62.1) pg/ml immediately after, 202.8 (24.2) pg/ml 30 min after, 239.7 (35.1) pg/ml 60 min after, and 199.6 (49.2) pg/ml 120 min after the exercise. We showed that plasma concentrations of IL-12 increased significantly immediately after brief anaerobic maximal cycle ergometer exercise (P < 0.01).

Novel neurotrophin-1/B cell-stimulating factor-3: a cytokine of the IL-6 family.

We have identified a cytokine of the IL-6 family and named it novel neurotrophin-1/B cell-stimulating factor-3 (NNT-1/BSF-3). NNT-1/BSF-3 cDNA was cloned from activated Jurkat human T cell lymphoma cells. Its sequence predicts a 225-aa protein with a 27-aa signal peptide, a molecular mass of 22 kDa in mature form, and the highest homology to cardiotrophin-1 and ciliary neurotrophic factor. The gene for NNT-1/BSF-3 is on chromosome 11q13. A murine equivalent to NNT-1/BSF-3 also was identified, which shows 96% homology to human NNT-1/BSF-3. NNT-1/BSF-3 mRNA is found mainly in lymph nodes and spleen. NNT-1/BSF-3 induces tyrosine phosphorylation of glycoprotein 130 (gp130), leukemia inhibitory factor receptor beta, and signal transducer and activator of transcription 3 in the SK-N-MC human neuroblastoma cells. NNT-1/BSF-3 shows activities typical of IL-6 family members. In vitro, it supports the survival of chicken embryo motor and sympathetic neurons. In mice, it induces serum amyloid A, potentiates the induction by IL-1 of corticosterone and IL-6, and causes body weight loss and B cell hyperplasia with serum IgG and IgM increase. NNT-1/BSF-3 is a gp130 activator with B-cell stimulating capability.