Recombinant Interleukin-24 Lacks Apoptosis-Inducing Properties in Melanoma Cells

IL-24, also known as melanoma differentiation antigen 7 (mda-7), is a member of the IL-10 family of cytokines and is mainly produced by Th2 cells as well as by activated monocytes. Binding of IL-24 to either of its two possible heterodimeric receptors IL-20R1/IL-20R2 and IL-22R/IL-20R2 activates STAT3 and/or STAT1 in target tissues such as lung, testis, ovary, keratinocytes and skin. To date, the physiological properties of IL-24 are still not well understood but available data suggest that IL-24 affects epidermal functions by increasing proliferation of dermal cells. In stark contrast to its “normal” and physiological behaviour, IL-24 has been reported to selectively and efficiently kill a vast variety of cancer cells, especially melanoma cells, independent of receptor expression and Jak-STAT signalling. These intriguing properties have led to the development of adenovirally-expressed IL-24, which is currently being evaluated in clinical trials. Using three different methods, we have analysed a large panel of melanoma cell lines with respect to IL-24 and IL-24 receptor expression and found that none of the investigated cell lines expressed sufficient amounts of functional receptor pairs and therefore did not react to IL-24 stimulation with Jak/STAT activation. Results for three cell lines contrasted with previous studies, which reported presence of IL-24 receptors and activation of STAT3 following IL-24 stimulation. Furthermore, evaluating four different sources and modes of IL-24 administration (commercial recombinant IL-24, bacterially expressed GST-IL-24 fusion protein, IL-24 produced from transfected Hek cells, transiently over-expressed IL-24) no induction or increase in cell death was detected when compared to appropriate control treatments. Thus, we conclude that the cytokine IL-24 itself has no cancer-specific apoptosis-inducing properties in melanoma cells

Alpha and lambda interferon together mediate suppression of CD4 T cells induced by respiratory syncytial virus

The mechanism by which respiratory syncytial virus (RSV) suppresses T-cell proliferation to itself and other antigens is poorly understood. We used monocyte-derived dendritic cells (MDDC) and CD4 T cells and measured [(3)H]thymidine incorporation to determine the factors responsible for RSV-induced T-cell suppression. These two cell types were sufficient for RSV-induced suppression of T-cell proliferation in response to cytomegalovirus or Staphylococcus enterotoxin B. Suppressive activity was transferable with supernatants from RSV-infected MDDC and was not due to transfer of live virus or RSV F (fusion) protein. Supernatants from RSV-infected MDDC, but not MDDC exposed to UV-killed RSV or mock conditions, contained alpha interferon (IFN-alpha; median, 43 pg/ml) and IFN-lambda (approximately 1 to 20 ng/ml). Neutralization of IFN-alpha with monoclonal antibody (MAb) against one of its receptor chains, IFNAR2, or of IFN-lambda with MAb against either of its receptor chains, IFN-lambdaR1 (interleukin 28R [IL-28R]) or IL-10R2, had a modest effect. In contrast, blocking the two receptors together markedly reduced or completely blocked the RSV-induced suppression of CD4 T-cell proliferation. Defining the mechanism of RSV-induced suppression may guide vaccine design and provide insight into previously uncharacterized human T-cell responses and activities of interferons

Cloning and characterization of IL-TIF, a new IL-10-related cytokine

Thèse de doctorat en sciences biomédicales (immunologie) (SBIM 3)--UCL, 200

IL-22 and its receptors, new players in the inflammatory network

Originally identified as a gene specifically induced by IL-9 in a mouse T cell lymphoma, IL-22 is mainly produced by TH1 cells or by activated T cells. Human IL-22, which shares 79% amino acid identity with its mouse orthologue and 25% with IL-10 is encoded by a single copy gene and located on chromosome 12, close to the IFNγ gene, whereas the murine IL-22 gene is located on chromosome 10 and is duplicated in some mouse strains. Structurally, IL-22 appears to be a monomer composed of six alpha helices, whose organization is reminiscent of the helices of the IL-10 dimer. Despite its structural relationship with IL-10, IL-22 exerts completely different activities, acting mainly on non hematopoietic cells, such as epithelial cells from lung and colon, hepatocytes and keratinocytes. IL-22 might therefore be involved in inflammatory processes, at least in liver and skin. IL-22 exerts its activity via a complex formed by IL-10Rβ and IL-22R, associated with Tyk2 and Jak1, respectively. The main signaling pathways triggered by IL-22 involve STAT-1,-3,-5 and the ERK, JNK and p38 MAPKinases. Beside its transmembrane receptor, IL-22 also binds to a soluble receptor, called IL-22BP. This soluble receptor turns out to be a natural antagonist of IL-22 biological activities at least in vitro. © 2006 Bentham Science Publishers Ltd

Viral and cellular interleukin-10 (IL-10)-related cytokines: from structures to functions.

The anti-inflammatory and immunosuppressive activities of IL-10 have been extensively studied during the last 10 years. More recently a series of new cytokines, structurally related to IL-10, were described. This family includes mda-7, IL-19, IL-20, IL-TIF/IL-22, and AK155. Most of the biological functions of these cytokines remain to be unraveled but new data are coming out steadily. Although none of these "IL-10 homologs" mimics IL-10 activities, they are likely to be involved in inflammatory processes as well. mda-7, IL-19 and IL-20 form a subfamily within IL-10 homologs, based on conserved amino acid sequences, and on the use of shared receptor complexes. Functional studies have stressed the potential suppressing activity of mda-7 on tumor growth. As for IL-20, its overexpression in transgenic mice led to skin abnormalities, reminiscent of psoriatic lesions in humans. IL-TIF/IL-22 is a Th1 cytokine, and was shown to upregulate the acute phase reactant production by liver cells. Finally, for AK155, originally described as a gene induced upon T cell transformation by Herpes-virus saimiri, functional data are still lacking to determine its biological activities

Manuel d’utilisation MACMA Salmo. Macro Excel d’Aide au Calcul de variables thermiques appliquées aux Milieux Aquatiques SALMOnicoles

Cet outil est une macro simple d’utilisation qui permet d’exploiter des données thermiques brutes sur les cours d’eau salmonicoles. La conception de cet outil de calcul a été initiée par la Fédération de Haute-Savoie pour la Pêche et la Protection des Milieux Aquatiques et l’INRA UMR CARRTEL de Thonon dans le cadre du programme INTERREG III « Truites autochtones » (2003-2006). Son but est de faciliter le traitement des données issues de suivis thermiques annuels de cours d’eau mis en place à partir de 2003

Cloning and characterization of IL-10-related T cell-derived inducible factor (IL-TIF), a novel cytokine structurally related to IL-10 and inducible by IL-9

IL-9 is a Th2 cytokine active on various cell types such as T and B lymphocytes, mast cells, and eosinophils, and potentially involved in allergy and asthma. To understand better the molecular mechanisms underlying the activity of this cytokine, we used a cDNA subtraction method to identify genes specifically induced by IL-9 in mouse T cells. One of the IL-9 regulated genes isolated by this approach turned out to encode a 180-amino acid long protein, including a potential signal peptide, and showing 22% amino acid identity with IL-10. This protein, designated IL-10-related T cell-derived inducible factor (IL-TIF), is induced by IL-9 in thymic lymphomas, T cells, and mast cells, and by lectins in freshly isolated splenocytes. Experiments concerning the mechanism regulating IL-TIF expression in T cells indicate that IL-9 induction is rapid (within 1 h), does not require protein synthesis, and depends on the activation of the Janus kinase (JAK)-STAT pathway. In vivo, constitutive expression of IL-TIF was detected by RT-PCR in thymus and brain, suggesting that the role of this new factor is not restricted to the immune system, Transfection of HEK293 cells with the IL-TIF cDNA resulted in the production of a glycosylated protein of about 25 kDa that was found to induce STAT activation in mesangial and neuronal cell lines. Further studies will have to address the possibility that some of the IL-9 activities may be mediated by IL-TIF

IL-9 induces 24P3 lipocalin gene expression in murine T cell lymphomas

Interleukin-9 (IL-9) is a Th2 cytokine whose overexpression is associated with asthma and T cell lymphomagenesis, All the IL-9 activities studied so far are mediated by a specific hemopoietin receptor that activates a Jak/STAT pathway. Searching for genes specifically modulated by IL-9, we observed that the 24P3 mRNA is strongly upregulated in BW5147 T lymphoma cells upon IL-9 stimulation, 24P3 is a member of the lipocalin family, and has been reported to bind N-formyl-Met-Leu-Phe, a potent neutrophil chemoattractant, and possibly other lipophylic mediators of inflammation. A similar 24P3 induction was observed in other T cell lymphomas (EL4 and TH201) in response to IL-9, as well as in EL4 cells stimulated with IL-6 or IL-1, By contrast, other IL-9-responsive cells such as mast cell line MC9 and B cell lymphoma A20 showed no 24P3 induction upon IL-9 stimulation. Experiments using IL-9R mutants indicated that STAT transcription factors, particularly STAT3, are involved in this process. However, 24P3 gene induction was slow, reaching a plateau from 36 to 72 hours after stimulation and was inhibited if cells were treated with cycloheximide during the first 8 hours of IL-9 stimulation, suggesting an indirect induction requiring new protein synthesis