Lymphokine research最新文献

The purpose of these studies was to determine whether the tumoricidal phenotype of human blood monocytes would be affected by different activation signals. Human monocytes obtained by elutriation of buffy coats were cultured in vitro in medium containing LPS, muramyltripeptide phosphatidylethanolamine (MTP-PE), or a lipopeptide analogue of gram-negative bacteria cell wall. These immunomodulators were added to monocytes in the presence or absence of IFN-gamma. Incubation with LPS, lipopeptide, and MTP-PE rendered the monocyte cytotoxic against allogeneic melanoma cells. Monocytes treated with LPS and lipopeptide (in the absence of IFN-gamma) secreted IL 1, TNF, and PGE2. In contrast, monocytes incubated with MTP-PE (in the absence of IFN-gamma) secreted only TNF. When the monocytes were coincubated with IFN-gamma (human but not mouse) and the immunomodulators, IL 1, TNF, and PGE2 were secreted at all test groups. These data show that some immunomodulators can regulate the release of TNF independently of IL 1 and that not all "activated tumoricidal macrophages" share identical phenotypes.

For their anti-inflammatory effects, glucocorticoids act, at least in part, by suppression of the production of interleukin-1 (IL-1), tumor necrosis factor alpha (TNF alpha) and prostaglandin E2 (PGE2) by activated monocytes/macrophages. Interleukin-4 (IL-4) also suppresses similar parameters of monocyte activation in vitro. However, contrasting effects of IL-4 and dexamethasone (Dex) on monocyte tissue-type plasminogen activator (t-PA) production suggest that these agents may operate by different pathways. We have now demonstrated that levels of IL-4 as low as 0.05-0.1 U/ml (0.6-1.2 x 10(-11)M) can augment the actions of Dex (5 x 10(-9)M) as an inhibitor of the production of monocyte pro-inflammatory mediators. These in vitro results suggest the possible supplementation of steroid therapy with low amounts of IL-4 (or an agonist) permitting the use of less steroid with concomitant reduction in steroid-associated side-effects. IL-4 can also suppress the increased release of IL-1 beta and TNF alpha by monocytes incubated with indomethacin, a non-steroidal anti-inflammatory drug.

The effect of moderate whole body hyperthermia (WBH) on the immunological responses of cancer patients was studied by monitoring their peripheral blood mononuclear cells (PBMC) in vitro. WBH of 2 degrees C above normal body temperature was induced in patients by utilizing a 433 MHz microwave system with a series of 6-9 external antennae. A total of three treatments were given with a frequency of one per week. Blood samples were drawn before treatment, when the target temperature was attained, and one hour after heating was discontinued. Changes in the number of PBMC, the mitogenic response, natural killer cell activity, and the production of Interleukin-1, Interleukin-2, and Interferon (IL-1, IL-2, IF) were measured in vitro. Mitogenic responses were increased 2-3 fold when the temperature was raised. Although there was an increase in the number of PBMC, during the course of heating, repeated treatment resulted in a selective and transient reduction in the number of PBMC. Nevertheless, the PBMC were capable of producing a higher level of cytokines and attained an enhanced ability to destroy target cells in vitro. The results indicate that, by inducing a fever-like condition, the immunological responses are enhanced in vitro.

We have previously described a novel protein, derived from the 3B6 EBV B-cell line which apparently displayed IL-1 bioactivity. We report here that the protein previously characterized is not a new species of IL-1. Indeed, we have now been able to clone and express a cDNA which identifies this protein as human thioredoxin, an intracellular dithiol oxydo-reductase enzyme. Thioredoxin however, is not a lymphokine and in particular does not possess IL-1 activity. Our earlier data can be explained in the light of recent findings, reported herein, indicating that IL-1 alpha is produced by the 3B6 line as assessed by antibody inhibition studies and IL-1 alpha mRNA expression. Thus our original protein preparation actually contained traces of IL-1 alpha, which was responsible for the biologic activities and thioredoxin.

This paper investigates the effect of recombinant human macrophage colony-stimulating factor (CSF-1) on the interaction between mononuclear phagocytes and the metastatic murine melanoma, B16/B16. CSF-1 had no effect on the ability of primary or bone marrow-derived macrophages to kill B16 cells in vitro, nor on their activation for cytotoxicity by gamma interferon plus LPS. However, when administered in vivo, CSF-1 increased the number of monocytes and peritoneal cells in tumor-bearing animals, and led to a significant reduction in the appearance of pulmonary and extra-pulmonary metastatic lesions derived from primary B16 tumors. The results suggest a therapeutic potential for CSF-1 in the treatment of malignancy.

We analyzed the proliferative response of DA1, DA1-a, NFS 60, 32DC1, Ea 3-17 and FDCP2 murine interleukin 3 (mIL3)-sensitive cell lines to human recombinant IL1 alpha, IL1 beta, IL2, IL4, IL5, IL6, granulocyte-CSF (G-CSF), macrophage-CSF (M-CSF), granulocyte-macrophage-CSF (GM-CSF), interferon gamma (IFN gamma), tumor necrosis factor (TNF) alpha, gibbon IL3, purified HILDA and mouse recombinant IL3, IL4, GM-CSF. All cell lines responded to mIL3 and IL4. Various response patterns were observed with human IL2, G-CSF and murine GM-CSF. Human IL4 and GM-CSF were absolutely inefficient in triggering proliferation of lines sensitive to their murine counterparts, confirming the species specificity of these two cytokines. Among the cell lines responding to G-CSF, some variations in sensitivities were observed. Thus the 32DC1 cell line needed 10 to 30 times more G-CSF to reach the same level of proliferation as the NFS60 cell line. DA1-a was the only factor-dependent cell line responding to purified HILDA, and IL6 was found to trigger proliferation of the NFS60 cell line, with a half-maximum effect observed for 0.1 pM of hormone.

During experiments aiming at the generation of monoclonal antibodies against native human interleukin 2 an antibody of different specificity was obtained, recognizing a polypeptide contaminant within the antigen preparation used for immunization. This antigen was shown to represent a release protein from human blood platelets. Amino acid sequence analysis of the immunopurified antigen revealed its identity as beta-thromboglobulin antigen. Depending on the source of antigen (freshly lysed platelets, platelet containing cell culture supernatants) various forms of the polypeptide, differing in the degree of N-terminal truncation, were found. Beta-thromboglobulin antigen preparations differing in peptide composition also had different capacities for modulating spontaneous as well as Fc-receptor dependent chemiluminescence of human monocytes and granulocytes. In contrast to former reports, no mitogenic activity for human dermal fibroblasts was found with beta-TG antigen (CTAP III) alone, but only in combination with human interleukin 1 and heparin, the three molecules acting synergistically. These findings indicate that beta-TG antigen could play a functional role in linking the blood clotting system to the immune system.

Incubation of human peripheral blood monocytes (PBM) with a partially purified thymic preparation, thymosin fraction (TF5), results in a dose dependent production of an interleukin-1 (IL-1)-like factor. The biological activity of this factor can be blocked by anti-IL-1 alpha, but not by anti-IL-1 beta which neutralizes bacterial induced IL-1 activity. Studies with further purified TF5 fractions show that this activity is not due to the well-characterized peptide, thymosin alpha 1 (T alpha 1), but rather a new thymosin peptide(s) isolated from a more basic fraction. Intraperitoneal injection of TF5 also induces the expression of a membrane-bound IL-1 (mIL-1) on mouse peritoneal cells. This study provides the first evidence that TF5 can influence macrophage activity directly by enhancing IL-1 production. This observation may help explain the mechanism by which TF5 modulates immune responses. These results also point to a more selective role for thymic hormones, growth factors and cytokines which may trigger macrophages to secrete different forms of IL-1, which can then regulate either immune and/or inflammatory processes.

The structure-function relationship in the human IL-1 beta protein has been analyzed by means of computer prediction, synthesis of peptides and use of monoclonal antibodies of predetermined specificity. A nine amino acid-long fragment (VQGEESNDK), corresponding to the human IL-1 beta sequence in position 163-171, was shown to possess only some of the IL-1 activities, i.e. those directed to the immune system, while being devoid of IL-1-like inflammatory effects. It is thus proposed that discrete domains within the IL-1 beta protein might be responsible for the different biological activities of the molecule and that the 163-171 fragment may represent one of the immunostimulatory sites of IL-1 beta.

Effect of interferon (IFN)s on fibroblast growth enhancing activity of tumor necrosis factor (TNF) was examined. IFN-gamma and -beta inhibited TNF-mediated growth stimulation of FS-4 cells. IFNs also inhibited dexamethasone (DEX)-mediated amplification of mitogenic activity of TNF. Significant inhibition was still demonstrable when IFN-gamma was added 2 days after treatment with TNF. On the other hand, no mitogenic activity of TNF was observed when cells were pretreated with IFN-gamma for 6h. These results suggested that interaction between TNF and IFN-gamma might play a role in modulation of some inflammatory processes in vivo.