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Query: UNIPROT:P05231 (interleukin-6)
 23,907 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Interleukin-6 (also called B cell stimulatory factor 2, hepatocyte activating factor, interferon-beta 2) has been shown to have effects on various lineages of hemopoietic cells. Some of its activities appear to overlap those of interleukin-1. In particular, recombinant murine IL-6 induced proliferation of phytohemagglutinin-activated thymocytes, an assay widely used to detect IL-1. In this report, we compared several features of IL-1 and IL-6 dependent thymocyte proliferation. The results indicate that IL-2 is the major second mediator of both IL-1 and IL-6 dependent proliferation. Finally, we tested whether IL-6 would also have activity in other T cell-based IL-1 assays using the T cell lymphoma LBRM33 1A5 and the T cell clone D10-G4.1. IL-6 had no activity in the latter two assays. These results indicate that IL-1 assays using LBRM33 1A5 and D10-G4.1 selectively detect Il-1, and are more specific assays for the detection of IL-1 in samples that may also contain IL-6.
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PMID:Biological activity of recombinant murine interleukin-6 in interleukin-1 T cell assays. 278 11

MHC nonrestricted cytotoxic cells play an important role in the killing of tumor cells in vitro and potentially in vivo. The activity of these cells is regulated by several cytokines such as IL-2 and IFN. In the present study we provide first evidence that IL-6 significantly augments the cytotoxic activity of human NK cells. IL-6 is produced by many different cells and is also known as IFN-beta 2, B cell stimulatory factor 2, hybridoma growth factor, hepatocyte-stimulating factor, and 26 kDa protein. IL-6 stimulates the activity of human CD3- NK cells but not that of CD3+ non-MHC-restricted cytotoxic T lymphocytes. As is the case with IL-2, the IL-6-mediated augmented cytotoxicity was a result of a more efficient lysis, but was not caused by an increased effector to target cell binding. Moreover, the effect of IL-6 on NK cell activity was blocked by a mAb directed against IL-2, and IL-6 itself was found to be a potent inducer of IL-2 production in cultured human PBMC. Thus it may be concluded that IL-6 enhances the cytotoxic activity of NK cells via IL-2. This newly recognized property of IL-6, which is produced by almost any cell, may be of importance in host defense against microbes and malignancies and therefore could contribute to improve the adoptive immunotherapy by using lymphokine-activated killer cells.
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PMID:IFN-beta 2/IL-6 augments the activity of human natural killer cells. 278 59

BSF-2 (B cell stimulatory factor-2/IL-6) is a member of the lymphokine family and responsible for B cell differentiation. Expression plasmids of human BSF-2 cDNA were constructed using a trp promotor/operator and a trpA terminator. In an extract of Escherichia coli HB101 holding "direct" expression plasmid pBSF-2D, activity of BSF-2 was detected, but overproduction was not observed. A "fused" expression system was therefore developed to prepare the recombinant protein. In this system, cDNA was expressed as a fused protein with human IL-2 N-terminal peptide. In the case of the fused BSF-2 expression plasmid, pBSF-2F, inclusion bodies were observed and overproduction of the protein occurred. As this fused protein had a Phe-Arg-Ala sequence at the junction of hIL-2 and BSF-2, it was possible to process mature BSF-2 from the fused BSF-2 by treatment with kallikrein and aminopeptidase P. From 1 liter of E. coli culture, 45 mg of mature BSF-2 was purified; it had a relative biological activity equal to that of natural BSF-2 purified from T cells.
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PMID:High-level expression of human BSF-2/IL-6 cDNA in Escherichia coli using a new type of expression-preparation system. 285 86

The cell line established from the lymph node cells of an MRL/lpr mouse, was found to have null cell properties in that it lacked Thy-1, Lyt-1 and Lyt-2 as well as sIg, and continued to grow in the absence of exogeneously added lymphokines such as IL-2 and IL-3. Interestingly, this cell line (KML1) or a soluble factor(s) produced by it promoted anti-ssDNA antibody production in cultures of MRL/lpr spleen cells. The factor did not induce cell proliferation. Therefore, it is concluded that the cell line KML1 produced at least a B-cell differentiation factor, but not IL-2 or IL-3 as far as detected with the respective lymphokine-dependent cell lines.
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PMID:An established MRL/Mp-lpr/lpr cell line with null cell properties produces a B cell differentiation factor(s) that promotes anti-single-stranded DNA antibody production in MRL spleen cell culture. 309 8

The synovial fluid of patients with rheumatoid arthritis (RA) contains a biologically active factor which has the ability to replace T cells for the induction of antibody secretion by human blood lymphoid cells stimulated by pokeweed mitogen (PWM) in vitro. This factor, which will be referred to as RA-SF (synovial fluid), also has the capacity to act as a B cell-stimulatory factor of mouse splenic lymphocytes in the presence of lipopolysaccharide (LPS). Using a test system developed for the definition of interleukin 4 (IL-4), which is a B cell-stimulating lymphokine which preferentially activates the synthesis of selected Ig classes in mouse lymphoid cells, we have shown that RA-SF has properties similar to IL-4 in that it induces differentiation of antibody secretion in the LPS-pretreated mouse cell, but unlike IL-4, which gives IgG1 and IgE, it selectively induces IgG2b synthesis. The present study demonstrates that RA-SF has a biological activity that is reminiscent of other B cell-stimulating mouse lymphokines, but it is biologically distinct from IL-2, IL-4, and IL-5. Recent data also indicate that it is distinct from gamma interferon (IFN-gamma). Therefore, we conclude that the biological activity of RA-SF has properties in common with a T-cell replacing (TRF) and B-cell differentiation factor (BCDF) and probably represents yet another biological activity which so far lacks an experimental counterpart. The relevance of this factor for autoantibody synthesis is discussed.
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PMID:Biological characterization of T cell-replacing factor in the synovial fluid of rheumatoid arthritis patients. 326 Jun 84

CD28 is an Ag of 44-kDa Mr that is expressed on the membrane of the majority of human T cells and that is recognized by mAb 9.3. The functional effects of mAb 9.3 on peripheral blood T cells were studied. mAb 9.3 was not mitogenic, unless it was combined with PMA. When CD28 was cross-linked after binding of mAb 9.3 to the T cell by immobilized or soluble anti-mouse IgG, T cells proliferated in response to rIL-2, provided that monocytes were also present. The additional signal required for IL-2 responsiveness after cross-linking of CD28 could also be delivered in cultures of purified T cells by a cellfree monocyte culture supernatant. Expression of IL-2R on about 10% of the T cells was demonstrated by staining with an anti-IL-2R mAb, and was found to be largely restricted to CD4+ cells. The active compound responsible for the helper signal in the monocyte culture supernatant was identified as IL-6 because purified IL-6 (but not IL-1 beta) had similar activity and because an antiserum to IL-6 (but not an antiserum to IL-1 beta) neutralized the activity of the monocyte supernatant and blocked T cell proliferation. An anti-IL-2R antibody also completely inhibited T cell proliferation induced by the combination of mAb 9.3, IL-2, and IL-6. Our results provide evidence that cross-linking of CD28 induces functional IL-2R and that this activity is dependent on a helper signal provided by monocytes, more specifically IL-6. Moreover, our results indicate that IL-6 (previously called B cell stimulatory factor-2) is active on T cells. If a natural ligand for CD28 can be identified, the mechanism of induction of IL-2 responsiveness described here might explain how T cells become nonspecifically involved in an ongoing cellular immune reaction.
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PMID:Cooperation between an anti-T cell (anti-CD28) monoclonal antibody and monocyte-produced IL-6 in the induction of T cell responsiveness to IL-2. 326 51

Murine interleukin-HP1 (HP1) was originally identified as a T-cell-derived lymphokine with growth factor activity for B-cell hybridomas and plasmacytomas. This growth factor was recently shown to stimulate both normal B-cell differentiation and T-cell growth factor activity. We have determined the complete amino acid sequence of HP1 on 40 micrograms (approximately 2 nmol) protein using a combination of sensitive microbore column (1.0 and 2.1 mm internal diameter) HPLC, peptide mapping and automated amino acid microsequence analysis. Ion-pairing chromatography was employed to isolate hydrophilic peptides which were not retained on conventional reversed-phase HPLC systems. The molecule consists of 187 amino acid residues with a calculated molecular mass of 21710 Da. Although there is virtually no similarity between the NH2-terminal region of HP1 and its human biological counterpart (26-kDa protein/interferon-beta 2 = B-cell stimulatory factor-2/interleukin-6), these studies demonstrate extensive amino acid similarity in the middle and COOH-terminal regions of these molecules suggesting that HP1 is the murine homologue of human interleukin-6.
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PMID:Murine hybridoma/plasmacytoma growth factor. Complete amino-acid sequence and relation to human interleukin-6. 326 59

Immunocompetent cells communicate via direct cellular contact and/or by the release and binding of soluble mediators. These soluble mediators transmit signals for growth and differentiation of various cell types. We have been intensively studying the regulation of human B lymphocytes and have focused on the events which occur following stimulation of mature, resting B cells with antigen or an antigen equivalent, anti-immunoglobulin antibody. Anti-Ig stimulates resting B lymphocytes to enlarge, synthesize RNA, increase membrane Ia expression, express activation markers, and become responsive to soluble factors termed B-cell growth factors (BCGF). We have described two different BCGFs, an 18 kd BCGF derived from a T-T hybridoma and a 60 kd BCGF derived from a T cell line. Activated B cells in the presence of BCGF further enlarge; express another activation marker, the transferrin receptor; and enter the S phase of the cell cycle, but do not differentiate unless another factor is present, e.g., B-cell differentiation factor (BCDF). We have described another T-T hybridoma which constitutively secretes both an 18 kd BCGF and a 35 kd BCDF. These two factors can easily be separated by biochemical means. The 35 kd BCDF induces the differentiation of activated but not resting B cells. Besides these B-cell-specific factors, we have studied the immunoregulatory effects of interleukin 1 (IL-1), IL-2, and interferons (alpha and gamma) on human B-cell responses. Interleukin 1 weakly co-stimulates resting B cells when it is present with anti-Ig and enhances the differentiation of activated and proliferating B cells when it is present in culture with BCDF. Interleukin 2 receptors as defined by the monoclonal antibody anti-Tac and radiolabeled IL-2-binding assays are present on in vitro activated B cells. Recombinant IL-2 added to cultures of in vitro activated B cells promotes both B-cell growth and B-cell differentiation into Ig-secreting cells. Finally, interferons appear to have little direct effect on human B-cell function. Major advances in our understanding of the complexities of B-cell activation, proliferation, and differentiation have been realized over the past few years. The eventual isolation and chemical characterization of the soluble mediators of B-cell function and the receptors for these mediators should lead to further insights and to new approaches to those diseases characterized by aberrations of B-cell function.
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PMID:Activation and immunoregulation of human B lymphocytes. 608 41

In a group of 111 patients with multiple myeloma (MM) comprising a group of 34 patients examined when the diagnosis was established and a group of 77 patients evaluated in different stages of the disease, the author examined the relationship between the interleukin-6 serum level (IL-6), assessed by the method of enzyme immunoanalysis and selected laboratory indicators of the disease. Elevated IL-6 values were recorded in 38% of the patients. In neither of the groups significant relations were found between IL-6 and calcium, urea, creatinine levels, the amount and type of monoclonal immunoglobulin, lacticode dehydrogenase, beta 2-microglobulin, ferritin, IL-2 and its soluble receptor in serum and the incidence of myeloma plasmocytes in bone marrow. In the second (but not in the first) group a significant relationship was recorded between IL-6 levels and the red cell sedimentation rate, the Hb value, the CRP level and serum albumin and the value of thymidinekinase in serum of patients with a value beyond the normal range. From the investigation ensues that examination of IL-6 serum levels in MM contributes so far mainly to improvement of the diagnosis and expedient classification of this disease in clinical practice.
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PMID:[Serum interleukin-6 in multiple myeloma: I. Relation to selected laboratory indicators of disease]. 748 49

Transfer of cytokine genes into tumor cells has proven a valuable approach for cancer treatment. In order to generate a more effective cancer vaccine, we transfected the human interleukin-6 (IL-6) gene into B16 melanoma cells. A B16 cell clone secreting the highest level of IL-6 was obtained by G418-resistant selection, limiting dilution and IL-6 assay. The IL-6-gene-transfected tumor cells exhibited in vitro growth inhibition, reduced tumorigenicity and decreased metastatic competence. After immunization with the inactivated IL-6-gene-transfected vaccine, the murine cytotoxic T lymphocyte activity, natural killer activity and lymphokine-activated killer activity increased markedly. After treatment with the vaccine, the tumor-bearing mice showed significant growth inhibition of subcutaneous tumor, reduction in pulmonary metastases and extension of survival time. The above therapeutic effect was better when low-dose IL-2 was administered simultaneously, although this dosage of IL-2 had no in vivo antitumor effect. These data demonstrated that IL-6-gene-transfected cancer vaccine has a potent antitumor effect via efficient induction of antitumor immunity, and a better therapeutic effect could be achieved when the vaccine is combined with low-dose IL-2 as adjuvant.
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PMID:Induction of antitumor immunity and treatment of preestablished tumor by interleukin-6-gene-transfected melanoma cells combined with low-dose interleukin-2. 749 43


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