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Interferons
Kinds of Interferons Selected AbstractsThe interferon alpha induced protein ISG12 is localized to the nuclear membraneFEBS JOURNAL, Issue 22 2001Pia M. Martensen Interferons exert their biological function mainly through the activation of interferon-stimulated genes (ISGs). ISG12 (originally designated p27) belongs to a family of small, interferon , inducible genes of unknown function. We have determined the 5, end sequence of ISG12 cDNA from the human cell lines HeLa and AMA by RACE. Comparing this sequence to ISG12 sequences in the expressed sequence tag (EST) database revealed the presence of two alternative splice variants of ISG12 in human cells exhibiting the same open reading frame. We have sequenced the promoter region of the ISG12 gene and found ISRE, IRF1/IRF2, and STAT elements correlating to the interferon , inducibility of the gene. Subsequently, we have expressed human ISG12, a 12-kDa hydrophobic protein in the baculovirus expression system and with a C-terminal FLAG-tag in the human cell line 293. Recombinant ISG12 sediments in the nuclear envelope in both cell types. Finally, we have been able to demonstrate the prevalence of the ISG12 gene product in the nuclear envelope of HeLa cells treated with interferon , by immunocytochemical analyses. ISG12 is the first interferon induced protein found localizing to the nuclear envelope. [source] ,-Interferons and the single nucleotide polymorphisms: A milestone to tailor-made therapy for chronic hepatitis CHEPATOLOGY RESEARCH, Issue 5 2010Yasuhito Tanaka Type III interferons (IFN) (IFN-,1, -,2, -,3/interleukin [IL]-29, -28A, -28B) are cytokines with type I IFN-like antiviral activities. Most cells have expressed both type I and III IFN following Toll-like receptor (TLR) stimulation or viral infection, whereas the ability of cells to respond to IFN-, was restricted to a specific subset of cells. It was reported that signal transduction pathway of IFN-, was similar to that of IFN-,/, although a receptor adapted by IFN-, were distinct from that of IFN-,/,. However, the clinical significance and the role of each IFN-, were unclear. Recent genome-wide association studies (GWAS) of the human whole genome revealed several single nucleotide polymorphism sites (SNP) strongly associated with the response to pegylated IFN-, (PEG-IFN) plus ribavirin (RBV) treatment in chronic hepatitis C patients. The SNP, which are located near the IL-28B gene of chromosome 19, were discovered simultaneously by three independent studies opening a new prospective in hepatitis C research. The present review highlights significant insights that can be derived from the GWAS approach, and summarizes current knowledge of in vitro and in vivo study on the role of IFN-, in antiviral effect. [source] Interferons as pathogenic effectors in autoimmunityIMMUNOLOGICAL REVIEWS, Issue 1 2005Roberto Baccala Summary:, Interferons (IFNs) type-1 (IFN ,/,) and type-II (IFN-,) are the most pleiotropic molecules in the intricate cytokine network. This dominance arises from three crucial factors: (i) initiation of IFN-,/, and IFN-, production at the inception of most innate immune responses, which primes for the ensuing adaptive immune responses, primarily through the sine qua non upregulation of major histocompatibility complex and costimulatory molecules; (ii) magnification of their production and signaling by cross-talk between themselves, and synergistic or antagonistic effects on other cytokines; and (iii) direct or indirect initiation of transcription of hundreds of immunologically relevant genes. Considering that aberrant immune responses against self-molecules seem to depend on the same constituents and pathways as those against exogenous antigens, it follows that IFNs are also major effectors in the pathogenesis of autoimmunity. Here, we review the diverse biological effects of IFNs on the immune system, discuss findings pertaining to the nature of exogenous and endogenous stimuli that might induce IFN production through the engagement of Toll-like receptors, and summarize the detrimental and, in some instances, beneficial effects of IFNs in systemic and organ-specific autoimmune diseases. [source] Interferons, interferon-like cytokines, and their receptorsIMMUNOLOGICAL REVIEWS, Issue 1 2004Sidney Pestka Summary:, Recombinant interferon-, (IFN-,) was approved by regulatory agencies in many countries in 1986. As the first biotherapeutic approved, IFN-, paved the way for the development of many other cytokines and growth factors. Nevertheless, understanding the functions of the multitude of human IFNs and IFN-like cytokines has just touched the surface. This review summarizes the history of the purification of human IFNs and the key aspects of our current state of knowledge of human IFN genes, proteins, and receptors. All the known IFNs and IFN-like cytokines are described [IFN-,, IFN-,, IFN-,, IFN-,, IFN-,, IFN-,, IFN-,, IFN-,, limitin, interleukin-28A (IL-28A), IL-28B, and IL-29] as well as their receptors and signal transduction pathways. The biological activities and clinical applications of the proteins are discussed. An extensive section on the evolution of these molecules provides some new insights into the development of these proteins as major elements of innate immunity. The overall structure of the IFNs is put into perspective in relation to their receptors and functions. [source] Interferons and viral infectionsBIOFACTORS, Issue 1 2009Volker Fensterl Abstract Interferons represent a family of cytokines, which is of central importance in the innate immune response to virus infections. All interferons act as secreted ligands of specific cell surface receptors, eliciting the transcription of hundreds of interferon-stimulated genes whose protein products have antiviral activity, as well as antimicrobial, antiproliferative/antitumor, and immunomodulatory effects. Expression of type I and III interferons is induced in virtually all cell types upon recognition of viral molecular patterns, especially nucleic acids, by cytoplasmic and endosomal receptors, whereas type II interferon is induced by cytokines such as IL-12, and its expression is restricted to immune cells such as T cells and NK cells. The effectiveness of the interferon system in counteracting viral infections is reflected by the multitude of inhibitors of interferon induction or interferon action that are encoded by many viruses, preventing their eradication and resulting in the continued coexistence of viruses and vertebrates. The unique biological functions of interferons have led to their therapeutic use in the treatment of diseases such as hepatitis, multiple sclerosis, and certain leukemias. © 2009 International Union of Biochemistry and Molecular Biology, Inc. [source] Type III IFNs: New layers of complexity in innate antiviral immunityBIOFACTORS, Issue 1 2009Nina Ank Abstract Cytokines are small secreted molecules, which mediate cross-talk between cells involved in the immune response. Interferons (IFN)s, constitute a class of cytokines with antiviral activities, and the type I IFNs have been ascribed particularly important roles in the innate antiviral response. Type III IFNs (also known as IFN-, or interleukin 28/29) represent a class of novel cytokines with biological activities similar to the type I IFNs, but seem to have a more specialized role in antiviral defense by exerting host-protection primarily at epithelial surfaces. In this review, we describe the current knowledge on the role of type III IFNs in antiviral defense. © 2009 International Union of Biochemistry and Molecular Biology, Inc. [source] Influenza A virus abrogates IFN-, response in respiratory epithelial cells by disruption of the Jak/Stat pathwayEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 6 2008Kohsaku Uetani Abstract The innate immunity to viral infections induces a potent antiviral response mediated by interferons (IFN). Although IFN-, is detected during the acute stages of illness in the upper respiratory tract secretions and in the serum of influenza A virus-infected individuals, control of influenza A virus is not dependent upon IFN-, as evidenced by studies using anti-IFN-, Ab and IFN-,,/, mice. Thus, we hypothesized that IFN-, is not critical in host survival because influenza A virus has mechanisms to evade the antiviral activity of IFN-,. To test this, A549 cells, an epithelial cell line derived from lung adenocarcinoma, were infected with influenza virus strain A/Aichi/2/68 (H3N2) (Aichi) and/or stimulated with IFN-, to detect IFN-,-stimulated MHC class II expression. Influenza A virus infection inhibited IFN-,-induced up-regulation of HLA-DR, mRNA and the IFN-, induction of class II transactivator (CIITA), an obligate mediator of MHC class II expression. Nuclear translocation of Stat1, upon IFN-, stimulation was significantly inhibited in influenza A virus-infected cells and this was associated with a decrease in Tyr701 and Ser727 phosphorylation of Stat1,. Thus, influenza A virus subverts antiviral host defense mediated by IFN-, through effects on the intracellular signaling pathways. [source] Requirement of HMGB1 and RAGE for the maturation of human plasmacytoid dendritic cellsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 7 2005Ingrid Abstract Dendritic cells (DC) are key components of innate and adaptive immune responses. Plasmacytoid DC (PDC) are a specialized DC subset that produce high amounts of type I interferons in response to microbes. High mobility group box 1 protein (HMGB1) is an abundant nuclear protein, which acts as a potent pro-inflammatory factor when released extracellularly. We show that HMGB1 leaves the nucleus of maturing PDC following TLR9 activation, and that PDC express on the plasma membrane the best-characterized receptor for HMGB1, RAGE. Maturation and type I IFN secretion of PDC is hindered when the HMGB1/RAGE pathway is disrupted. These results reveal HMGB1 and RAGE as the first known autocrine loop modulating the maturation of PDC, and suggest that antagonists of HMGB1/RAGE might have therapeutic potential for the treatment of systemic human diseases. [source] Viral infection and Toll-like receptor agonists induce a differential expression of type,I and , interferons in human plasmacytoid and monocyte-derived dendritic cellsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 3 2004Eliana Abstract In humans, the type,I interferon (IFN) family consists of 13 IFN-, subtypes, IFN-, and IFN-o the newly discovered IFN-like family consists of IFN-,1, -,2 and -,3. We have investigated the expression of type,I and , IFN genes following virus infections or Toll-like receptor (TLR) triggering in monocyte-derived DC (MDDC) and plasmacytoid DC (pDC). We found thatall IFN-,, -,, -o and -, subtypes are expressed in influenza-virus-infected MDDC or pDC. Conversely, differential type,I IFN gene transcription was induced in MDDC and pDC stimulated by specific TLR agonists. TLR-9 stimulation by CpG DNA induced the expression of all IFN-,, -,, -o and -, subtypes in pDC, whereas TLR-4 stimulation by LPS, or TLR-3 stimulation bypoly I:C, induced only IFN-, and IFN-, gene expression in MDDC. The expression pattern of IFN regulatory factor (IRF)-5 and IRF-7 in MDDC and pDC was also determined. IRF-5 was constitutively expressed in the two DC subsets whereas IRF-7 was constitutive in pDC but its expression was induced along MDDC maturation. Overall, our data indicate that the coordinated expression of IFN-, with IFN-, would be of crucial importance for the maturation of DC. [source] A longitudinal observational study of a cohort of patients with relapsing,remitting multiple sclerosis treated with glatiramer acetateEUROPEAN JOURNAL OF NEUROLOGY, Issue 11 2007M. Debouverie Immunomodulatory treatments for relapsing,remitting multiple sclerosis (RRMS) are not efficacious or tolerated in all patients. It is important to evaluate alternative classes of treatment in patients failing first-line therapy. The objective of this prospective observational study was to evaluate the efficacy and safety of glatiramer acetate in patients, to whom , -interferons could not be administered. The study included patients with RRMS who were intolerant to or had contraindications to , -interferon. After initiation of glatiramer acetate treatment, follow-up visits were made every 3 months, when data on neurologist-ascertained relapses and disability [Expanded Disability Status Scale (EDSS) score] were collected. Tolerability was evaluated by spontaneous adverse event reporting. Overall, 205 patients were studied and 113 (55.1%) treated for at least 4 years. The proportion of patients presenting over three relapses per year decreased from 51.2% to 8.4% in the 2 years following treatment initiation. Over 5 years of treatment, mean annualized relapse rates and mean EDSS scores remained stable (0.4,0.6 relapses/year and 3.6 ± 1.8,3.3 ± 2.1 respectively). Adverse events were reported by 179 patients, leading to discontinuation of treatment in 10 patients. Patients with RRMS to whom , -interferons cannot be prescribed can benefit from treatment with glatiramer acetate. [source] Distinct roles of protein kinase R and toll-like receptor 3 in the activation of astrocytes by viral stimuliGLIA, Issue 3 2007Pamela A. Carpentier Abstract Impaired immune surveillance and constitutive immunosuppressive properties make the central nervous system (CNS) a particular challenge to immune defense, and require that CNS-resident cells be capable of rapidly recognizing and responding to infection. We have previously shown that astrocytes respond to treatment with a TLR3 ligand, poly I:C, with the upregulation of innate immune functions. In the current study, we examine the activation of innate immune functions of astrocytes by Theiler's murine encephalomyelitis virus (TMEV), a picornavirus, which establishes a persistent infection in the CNS of susceptible strains of mice and leads to the development of an autoimmune demyelinating disease that resembles human multiple sclerosis. Astrocytes infected with TMEV are activated to produce type I interferons, the cytokine IL-6, and chemokines CCL2 and CXCL10. We further examined the mechanisms that are responsible for the activation of astrocytes in response to direct viral infection and treatment with poly I:C. We found that the cytoplasmic dsRNA-activated kinase PKR is important for innate immune responses to TMEV infection, but has no role in their induction by poly I:C delivered extracellularly. In contrast, we found that TLR3 has only a minor role in responses to TMEV infection, but is important for responses to poly I:C. These results highlight the differences between responses induced by direct, nonlytic virus infection and extracellular poly I:C. The activation of astrocytes through these different pathways has implications for the initiation and progression of viral encephalitis and demyelinating diseases such as multiple sclerosis. © 2006 Wiley-Liss, Inc. [source] Bell's palsy during interferon therapy for chronic hepatitis C infection in patients with haemorrhagic disordersHAEMOPHILIA, Issue 2 2000Ogundipe Two adult patients with life-long severe haemorrhagic disorders commenced on interferon-,2b therapy for chronic hepatitis C infection. Both developed Bell's palsy several weeks after commencing therapy, They were started on steroids and, in addition, the first patient discontinued interferon-,2b therapy while the second patient elected to continue with therapy. In both cases facial paralysis improved over the ensuing weeks. Bell's palsy is often idiopathic but has been reported. in association with herpesviruses. It is not a recognised complication of chronic hepatitis B or C infection, or interferon-,2b therapy. However, the interferons are associated with numerous adverse reactions including various neuropsychiatric manifestations and neurological syndromes. There are several reports of nerve palsies, including optic tract neuropathy, occurring during interferon therapy, and immune-based mechanisms are thought to play a role in the aetiopathogenesis. No reports of Bell's palsy in association with interferon therapy were identified in our literature search, although one possible case has been reported to the Committee of Safety in Medicine. Although Bell's palsy in our patients may have occurred by chance, a neuropathic effect of interferon-,2b on the facial nerve cannot be excluded and we urge physicians using interferons to be aware of this potential side-effect. [source] ,-Interferons and the single nucleotide polymorphisms: A milestone to tailor-made therapy for chronic hepatitis CHEPATOLOGY RESEARCH, Issue 5 2010Yasuhito Tanaka Type III interferons (IFN) (IFN-,1, -,2, -,3/interleukin [IL]-29, -28A, -28B) are cytokines with type I IFN-like antiviral activities. Most cells have expressed both type I and III IFN following Toll-like receptor (TLR) stimulation or viral infection, whereas the ability of cells to respond to IFN-, was restricted to a specific subset of cells. It was reported that signal transduction pathway of IFN-, was similar to that of IFN-,/, although a receptor adapted by IFN-, were distinct from that of IFN-,/,. However, the clinical significance and the role of each IFN-, were unclear. Recent genome-wide association studies (GWAS) of the human whole genome revealed several single nucleotide polymorphism sites (SNP) strongly associated with the response to pegylated IFN-, (PEG-IFN) plus ribavirin (RBV) treatment in chronic hepatitis C patients. The SNP, which are located near the IL-28B gene of chromosome 19, were discovered simultaneously by three independent studies opening a new prospective in hepatitis C research. The present review highlights significant insights that can be derived from the GWAS approach, and summarizes current knowledge of in vitro and in vivo study on the role of IFN-, in antiviral effect. [source] The role of type I interferons in non-viral infectionsIMMUNOLOGICAL REVIEWS, Issue 1 2004Christian Bogdan Summary:, For a long time, the family of type I interferons (IFN-,/,) has received little attention outside the fields of virology and tumor immunology. In recent years, IFN-,/, regained the interest of immunologists, due to the phenotypic and functional characterization of IFN-,/,-producing cells, the definition of novel immunomodulatory functions and signaling pathways of IFN-,/,, and the observation that IFN-,/, not only exerts antiviral effects but is also relevant for the pathogenesis or control of certain bacterial and protozoan infections. This review summarizes the current knowledge on the production and function of IFN-,/, during non-viral infections in vitro and in vivo. [source] RNase L: Its biological roles and regulationIUBMB LIFE, Issue 9 2006Shu-Ling Liang Abstract 2'-5'oligoadenylate-dependent ribonuclease L (RNase L) is one of the key enzymes involved in the function of interferons (IFNs), a family of cytokines participating in innate immunity against viruses and other microbial pathogens. Upon binding with its activator, 5'-phosphorylated, 2'-5' linked oligoadenylates (2-5A), RNase L degrades single-stranded viral and cellular RNAs and thus plays an important role in the antiviral and antiproliferative functions of IFNs. In recent years, evidence has revealed that RNase L displays a broad range of biological roles which are summarized in this review. iubmb Life, 58: 508-514, 2006 [source] Non-conventional signal transduction by type 1 interferons: The NF-,B pathwayJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 5 2007Ziyun Du Abstract Type I interferons (IFNs) regulate diverse cellular functions by modulating the expression of IFN-stimulated genes (ISGs) through the activation of the well established signal transduction pathway of the Janus Kinase (JAK) and signal transducers and activators of transcription (STAT) proteins. Although the JAK,STAT signal transduction pathway is critical in mediating IFN's antiviral and antiproliferative activities, other signaling pathways are activated by IFNs and regulate cellular response to IFN. The NF-,B transcription factor regulates the expression of genes involved in cell survival and immune responses. We have identified a novel IFN mediated signal pathway that leads to NF-,B activation and demonstrate that a subset of ISGs that play key roles in cellular response to IFN is regulated by NF-,B. This review focuses on the IFN-induced NF-,B activation pathway and the role of NF-,B in ISG expression, antiviral activity and apoptosis, and the therapeutic application of IFN in cancer and infectious disease. J. Cell. Biochem. 102: 1087,1094, 2007. © 2007 Wiley-Liss, Inc. [source] Toll-like receptors and their role in gastrointestinal diseaseJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 6 2009Adam G Testro Abstract The innate immune response to invading pathogens is centred upon a family of non-clonal, germline-encoded pattern recognition receptors (PRRs), the Toll-like receptors (TLRs). These provide specificity for a vast range of microbial pathogens, and offer an immediate anti-microbial response system. Thirteen mammalian TLRs have been described; 10 are expressed in humans, each responsible for the recognition of distinct, invariant microbial structures originating from bacteria, viruses, fungi and protozoa. The two most thoroughly studied are TLR4 and TLR2, the PRRs for Gram-negative and Gram-positive bacterial products, respectively. TLR4 is also the major receptor recognising endogenous ligands released from damaged or dying cells. Activation of a TLR by its relevant ligand rapidly ignites a complex intracellular signaling cascade that ultimately results in upregulation of inflammatory genes and production of proinflammatory cytokines, interferons and recruitment of myeloid cells. It also stimulates expression, upon antigen presenting cells, of co-stimulatory molecules required to induce an adaptive immune response. Whilst a robust TLR response is critical for survival and defence against invading pathogens, inappropriate signaling in response to alterations in the local microflora environment can be detrimental. Such ,unhelpful TLR responses' could form the basis for a large number of gastrointestinal and liver disorders, including inflammatory bowel disease, viral hepatitis, autoimmune liver diseases and hepatic fibrosis. As our understanding of TLRs expands, the pathogenesis of a number of gastrointestinal disorders will be further elucidated, and this offers potential for specific therapies aimed directly at TLR signaling. [source] Effect of interferons on P-glycoprotein-mediated rhodamine-123 efflux in cultured rat hepatocytesJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 10 2002Yukiko Akazawa Abstract The effect of interferon (IFN)-, and IFN-, on P-glycoprotein (P-gp)-mediated efflux of rhodamin-123(Rho-123), a typical substrate of P-gp, was studied in rat hepatocytes in primary culture. After treatment with IFN-,, IFN-,, or both for 3 days, steady-state levels of Rho-123, incorporated into the hepatocytes, were measured to evaluate the P-gp activity. Whereas IFN-, did not affect the intracellular level of Rho-123, IFN-, treatment caused a significant increase of the level, suggesting that IFN-, treatment suppresses the expression of P-gp or its activity. A combination of the two types of IFN exhibited a similar effect to that of IFN-, alone. The effect of IFN-, was still observed in the presence of H2O2, which enhances the expression and activity of P-gp. Immunoblot analysis using a monoclonal antibody C219 revealed, however, that P-gp expression was increased after treatment with IFN-,, but only slightly by IFN-, treatment. These results suggest that the enhanced Rho-123 uptake of rat primary hepatocytes induced by IFN-, does not result from reduced expression of P-gp but, rather, from impaired maturation or dysfunction of the efflux transporter. © 2002 Wiley-Liss Inc. and the American Pharmaceutical Association J Pharm Sci 91:2110,2115, 2002 [source] Old and emerging therapies in chronic hepatitis C: an updateJOURNAL OF VIRAL HEPATITIS, Issue 1 2008M. Deutsch Summary., The main goal of therapy in hepatitis C virus (HCV) infection is to achieve a sustained virological response currently defined as undetectable HCV-RNA in peripheral blood determined with the most sensitive polymerase chain reaction technique 24 weeks after the end of treatment. This goal is practically equivalent with eradication of HCV infection and cure of the underlying HCV-induced liver disease. The current standard in hepatitis C treatment consists in combination regimens of pegylated interferon-, (Peg-INF-,) with Ribavirin (RBV). Such treatment schemes are quite successful in patients with HCV genotypes 2 and 3 infections achieving HCV eradication rates of 75,90%. However, they are much less effective in patients with genotypes 1 and 4 infections with eradication rates ranging between 45% and 52%. Moreover, they have several, and sometimes severe, adverse effects and contraindications, further limiting their efficacy and applicability in an appreciable number of patients with chronic HCV-induced liver disease. Therefore, the need for improvement of existing therapies and for development of new effective, safe and tolerable drugs is a matter of great clinical relevance and importance. In this article, recent improvements in the current standard of therapy with IFN-, and RBV in various subsets of patients with chronic hepatitis C and in the clinical development of new emerging drugs, particularly small molecules, will be reviewed and commented. The article is divided in two main parts: (i) improvements in the standard combination therapies and schemes of approved Peg-INF-, with RBV and expectations from new interferons, interferon inducers and alternatives to RBV; (ii) new drugs for HCV in clinical development focusing mostly on specific inhibitors of HCV and less so on other drugs including immune therapies. [source] 48 weeks pegylated interferon alpha-2a is superior to 24 weeks of pegylated interferon alpha-2b in achieving hepatitis B e antigen seroconversion in chronic hepatitis B infectionALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 8 2006C.-K. HUI Summary Background/aim, Although 48-week therapy with pegylated-interferons has been shown to be effective for the treatment of chronic hepatitis B virus infection, the efficacy of a shorter duration of therapy with pegylated interferons is unknown. Method, We reviewed 53 hepatitis B e antigen positive Chinese patients treated with 48 weeks of pegylated interferon alpha-2a or 24 weeks of pegylated interferon alpha-2b. Sustained virological response was defined as hepatitis B e antigen seroconversion and hepatitis B virus DNA <105 copies/mL at week 72. Results, Twenty-nine patients were treated with 48 weeks of pegylated-interferon-alpha-2a and 24 patients with 24 weeks of pegylated-interferon-alpha-2b. At the end-of-therapy, hepatitis B e antigen seroconversion and hepatitis B virus DNA <105 copies/mL were similar between the two groups of patients [9/29 (31.0%) vs. 2/24 (8.3%), respectively, P = 0.09]. At week 72, 10 of the 29 patients (34.5%) treated with 48 weeks of pegylated-interferon-alpha-2a compared with two of the 24 patients (8.3%) treated with 24 weeks of pegylated-interferon-alpha-2b had sustained virological response (P = 0.04). By logistic analysis, 48 weeks of pegylated-interferon-alpha-2a was independently associated with sustained virological response (P = 0.04 adjusted hazards-ratio 9.37). Conclusion, Further studies are required to determine the optimal duration of therapy with pegylated interferons in chronic hepatitis B. [source] Pegylated interferons: chemical and clinical differencesALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 8 2004G. R. Foster Summary Pegylated interferon therapy for the treatment of chronic hepatitis C virus provides significant increases in sustained virological response rates compared with standard interferons. Two pegylated interferons are now available and are used in conjunction with ribavirin to maximize response rates in infected patients. The two pegylated interferons, peginterferon, -2a and peginterferon, -2b, differ substantially in terms of their chemical and structural characteristics, pharmacokinetic and pharmacodynamic properties, and dosing and administration. A full understanding of the differences between the two drugs is important to maximize the clinical benefits. Controlled studies designed to characterize the effects of the two drugs on viral kinetics and sustained virological response rates are emerging and may help to shed additional light on the use of these compounds in patients with chronic hepatitis C. [source] Interleukin-12 family members and type I interferons in Th17-mediated inflammatory disordersALLERGY, Issue 5 2009S. Goriely Cytokines produced by antigen-presenting cells govern the fate of helper T-cell responses. Herein, we review the impact of interleukin (IL)-23 and IL-27 on the outcome of T-helper (Th) 17 cell responses and discuss their impact in the pathogenesis of T-cell-mediated inflammatory disorders of autoimmune or allergic origin. We then discuss how type I interferons might influence the course of autoimmune diseases by tipping the balance between IL-12 family members. [source] Respiratory virus induction of alpha-, beta- and lambda-interferons in bronchial epithelial cells and peripheral blood mononuclear cellsALLERGY, Issue 3 2009M. R. Khaitov Background:, Respiratory viruses, predominantly rhinoviruses are the major cause of asthma exacerbations. Impaired production of interferon-, in rhinovirus infected bronchial epithelial cells (BECs) and of the newly discovered interferon-,s in both BECs and bronchoalveolar lavage cells, is implicated in asthma exacerbation pathogenesis. Thus replacement of deficient interferon is a candidate new therapy for asthma exacerbations. Rhinoviruses and other respiratory viruses infect both BECs and macrophages, but their relative capacities for ,-, ,- and ,-interferon production are unknown. Methods:, To provide guidance regarding which interferon type is the best candidate for development for treatment/prevention of asthma exacerbations we investigated respiratory virus induction of ,-, ,- and ,-interferons in BECs and peripheral blood mononuclear cells (PBMCs) by reverse transferase-polymerase chain reaction and enzyme-linked immunosorbent assay. Results:, Rhinovirus infection of BEAS-2B BECs induced interferon-, mRNA expression transiently at 8 h and interferon-, later at 24 h while induction of interferon-, was strongly induced at both time points. At 24 h, interferon-, protein was not detected, interferon-, was weakly induced while interferon-, was strongly induced. Similar patterns of mRNA induction were observed in primary BECs, in response to both rhinovirus and influenza A virus infection, though protein levels were below assay detection limits. In PBMCs interferon-,, interferon-, and interferon-, mRNAs were all strongly induced by rhinovirus at both 8 and 24 h and proteins were induced: interferon-,>-,>-,. Thus respiratory viruses induced expression of ,-, ,- and ,-interferons in BECs and PBMCs. In PBMCs interferon-,>-,>-, while in BECs, interferon-,>-,>-,. Conclusions:, We conclude that interferon-,s are likely the principal interferons produced during innate responses to respiratory viruses in BECs and interferon-,s in PBMCs, while interferon-, is produced by both cell types. [source] Immunopathogenesis of juvenile dermatomyositisMUSCLE AND NERVE, Issue 5 2010Sahil Khanna MBBS Abstract There is increasing evidence for involvement of the mechanisms of the innate immune system in the pathogenesis of idiopathic inflammatory myopathies (IIMs), especially in the adult and juvenile forms of dermatomyositis. Juvenile dermatomyositis (JDM) is the most common form of childhood IIM, and this review focuses on recent advances in understanding the actions of the innate immune system in this condition. Over the last few years, great strides have been made in understanding immune dysregulation in IIM, including JDM. Novel autoantibodies have been identified, and new genetic contributions have been described. Among the most striking findings is type I interferon activity in JDM tissue and peripheral blood. This is in conjunction with the description of dysregulation of the major histocompatibility complex (MHC) class I gene and identification of plasmacytoid dendritic infiltrates as the possible cellular source of type I interferons. These findings also point toward the potential prognostic value of muscle biopsies and have helped expand our understanding of the etiopathogenesis of IIM. Muscle Nerve 41: 581,592, 2010 [source] Current treatments of chronic immune-mediated demyelinating polyneuropathiesMUSCLE AND NERVE, Issue 5 2009Thomas H. Brannagan III MD Abstract Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), multifocal motor neuropathy (MMN), and anti,myelin-associated glycoprotein (anti-MAG) neuropathy are three demyelinating acquired neuropathies, with distinct responses to immunotherapy. In placebo-controlled, double-blind, randomized trials, intravenous immunoglobulin (IVIg) has been effective for CIDP and MMN, and plasmapheresis has been effective for CIDP. Corticosteroids have been beneficial in controlled trials for CIDP. Other agents, including cyclophosphamide, rituximab, azathioprine, cyclosporine, interferons, fludarabine, mycophenolate mofetil, and etanercept, have been reported to benefit some patients with inflammatory demyelinating neuropathies in case series and case reports. This review examines the use and toxicity associated with these immunotherapy medications in treating patients with chronic immune-mediated demyelinating neuropathies. Muscle Nerve, 2009 [source] The Role of Cytokines in Regulating Protein Metabolism and Muscle FunctionNUTRITION REVIEWS, Issue 2 2002Elena Zoico M.D. Multiple lines of evidence suggest that cytokines influence different physiologic functions of skeletal muscle cells, including anabolic and catabolic processes and programmed cell death. Cytokines play an important role not only in muscle homeostasis, therefore, but also in the pathogenesis of different relevant clinical conditions characterized by alterations in protein metabolism. Recently discovered cytokines, such as ciliary neurotrophic factor and growth/differentiation factor-8, as well as the more studied tumor necrosis factor-,, interleukin-1, interleukin-6, and the interferons, have been implicated in the regulation of muscle protein turnover. Their postreceptor signaling pathways, proteolytic systems, and the mechanisms of protein synthesis inhibition involved in different catabolic conditions have been partially clarified. Moreover, recent studies have shown that cytokines can directly influence skeletal muscle contractility independent of changes in muscle protein content. Even though several gaps remain in our understanding, these observations may be useful in the development of strategies to control protein metabolism and muscle function in different clinical conditions. [source] Effects of Echinacea extracts on macrophage antiviral activitiesPHYTOTHERAPY RESEARCH, Issue 6 2010David S. Senchina Abstract Type I interferons are a class of cytokines synthesized by leukocytes such as macrophages that limit viral replication. We hypothesized that one mechanism whereby Echinacea spp. extracts may enhance immunity is through modulating interferon-associated macrophage pathways. We used herpes simplex viral infection in the murine macrophage cell line RAW264.7 and monitored virus-induced cell death, interferon secretion, and two intracellular proteins that indicate activation of interferon pathways. Cells were incubated with control media or extracts from four different species (E. angustifolia, E. purpurea, E. tennesseensis, E. pallida). Cells incubated with extracts prior to infection showed very modest enhancement of viability, and no increase in the secretion of interferons , or , as compared to control cells. Virus-infected macrophages treated with extracts from E. purpurea showed a small (<2-fold) induction of guanylate binding protein (GBP) production, but no effect of extracts from other species was observed. In virus-infected cells, all the extracts increased the amount of inducible nitric oxide synthase (iNOS) protein, and this effect varied by type of extraction preparation. Together, these results suggest that any potential antiviral activities of Echinacea spp. extracts are likely not mediated through large inductions of Type I interferon, but may involve iNOS. Copyright © 2009 John Wiley & Sons, Ltd. [source] Determination of the human type I interferon receptor binding site on human interferon-,2 by cross saturation and an NMR-based model of the complexPROTEIN SCIENCE, Issue 11 2006Sabine R. Quadt-Akabayov Abstract Type I interferons (IFNs) are a family of homologous helical cytokines that exhibit pleiotropic effects on a wide variety of cell types, including antiviral activity and antibacterial, antiprozoal, immunomodulatory, and cell growth regulatory functions. Consequently, IFNs are the human proteins most widely used in the treatment of several kinds of cancer, hepatitis C, and multiple sclerosis. All type I IFNs bind to a cell surface receptor consisting of two subunits, IFNAR1 and IFNAR2, associating upon binding of interferon. The structure of the extracellular domain of IFNAR2 (R2-EC) was solved recently. Here we study the complex and the binding interface of IFN,2 with R2-EC using multidimensional NMR techniques. NMR shows that IFN,2 does not undergo significant structural changes upon binding to its receptor, suggesting a lock-and-key mechanism for binding. Cross saturation experiments were used to determine the receptor binding site upon IFN,2. The NMR data and previously published mutagenesis data were used to derive a docking model of the complex with an RMSD of 1 Å, and its well-defined orientation between IFN,2 and R2-EC and the structural quality greatly improve upon previously suggested models. The relative ligand,receptor orientation is believed to be important for interferon signaling and possibly one of the parameters that distinguish the different IFN I subtypes. This structural information provides important insight into interferon signaling processes and may allow improvement in the development of therapeutically used IFNs and IFN-like molecules. [source] Type I Interferons Are Not Critical for Skin Allograft Rejection or the Generation of Donor-Specific CD8+ Memory T CellsAMERICAN JOURNAL OF TRANSPLANTATION, Issue 1 2010M. H. Oberbarnscheidt Type I interferons (IFN-I) link innate to adaptive immunity in microbial infection, autoimmune disease and tumor immunity. It is not known whether IFN-I have an equally central role in alloimmunity. Here we tested this possibility by studying skin allograft survival and donor-specific CD8+ T-cell responses in mice that lack the IFN-I receptor (IFN-IR,/,). We found that IFN-IR,/, mice reject fully allogeneic wild-type skin grafts at the same rate as wild-type recipients. Similarly, allograft rejection was not delayed if IFN-IR,/, male skin was transplanted to syngeneic IFN-IR,/, female mice. Quantitation of the male (H-Y)-specific CD8+ T-cell response in these mice revealed normal generation of donor-specific CD8+ effector T cells but fourfold reduction in CD8+ memory T cells. Memory CD8+ T cells generated in the absence of IFN-IR had normal phenotype and recall function, assessed by ex vivo cytokine production and the ability of IFN-IR,/, mice to mount second set rejection. Finally, these memory T cells were maintained at a constant number despite their inability to respond to IFN-1. Our findings indicate that IFN-I cytokines are not critical for acute allograft rejection or for the expansion and differentiation of donor-specific CD8+ T cells into long-lived, functional memory T cells. [source] Interferon-stimulated gene 15 (ISG15) conjugates proteins in dermatomyositis muscle with perifascicular atrophyANNALS OF NEUROLOGY, Issue 1 2010Mohammad Salajegheh MD Objective We investigated interferon-stimulated gene 15 (ISG15), a poorly understood ubiquitin-like modifier, and its enzymatic pathway in dermatomyositis (DM), an autoimmune disease primarily involving muscle and skin. Methods We generated microarray data measuring transcript abundance for approximately 18,000 genes in each of 113 human muscle biopsy specimens, and studied biopsy specimens and cultured skeletal muscle using immunohistochemistry, immunoblotting proteomics, real-time quantitative polymerase chain reaction, and laser-capture microdissection. Results Transcripts encoding ISG15-conjugation pathway proteins were markedly upregulated in DM with perifascicular atrophy (DM-PFA) muscle (ISG15 339-fold, HERC5 62-fold, and USP18 68-fold) compared with 99 non-DM samples. Combined analysis with publicly available microarray datasets showed that >50-fold ISG15 transcript elevation had 100% sensitivity and specificity for 28 biopsies from adult DM-PFA and juvenile DM patients compared with 199 muscle samples from other muscle diseases. Free ISG15 and ISG15-conjugated proteins were only found on immunoblots from DM-PFA muscle. Cultured human skeletal muscle exposed to type 1 interferons produced similar transcripts and ISG15 protein and conjugates. Laser-capture microdissection followed by proteomic analysis showed deficiency of titin in DM perifascicular atrophic myofibers. Interpretation A large-scale microarray study of muscle samples demonstrated that among a diverse group of muscle diseases DM was uniquely associated with upregulation of the ISG15 conjugation pathway. Exposure of human skeletal muscle cell culture to type 1 interferons produced a molecular picture highly similar to that seen in human DM muscle. Perifascicular atrophic myofibers in DM were deficient in a number of skeletal muscle proteins including titin. ANN NEUROL 2010;67:53,63 [source] | |||||||||||||||||||||||||||||||||||||