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Results for “Type I interferon”

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PubMed1998

Are all type I human interferons equivalent?

The Type I interferons are a family of closely related cytokines that have antiviral and immunostimulatory properties. There has been prolonged debate regarding the different interferon-alpha subtypes: with some authorities suggest that the different interferons have essentially similar properties but others argue that there are significant differences between them. Recent work has shown that the various interferon-alpha subtypes can interact with the interferon receptor components in different ways and can activate a number of different signalling pathways. Recent studies on the immunomodulatory properties of the Type I interferons indicate that there are profound differences between the subtypes. The clinical significance of all these differences remains to be determined.

Animals↗

PubMed1998

A novel sensitive and selective bioassay for human type I interferons.

We describe a novel MxA gene-induction assay for type I interferons (IFN-alpha and IFN-beta) based on the specific induction of the MxA gene in cultured human cells. Accumulated intracellular MxA protein is determined by immunologic measurement by a rapid method using commercially available materials. IFN activity can be measured accurately over a concentration range of 0.1-30 IU/ml. In contrast, type II IFN and other cytokines are not significantly detected. The MxA-induction assay has advantages in terms of specificity, reliability, and sensitivity over other methods for assaying type I IFN. It has also been adapted and validated for measuring the titers of anti-IFN-beta neutralizing antibodies in human sera.

Antiviral Agents↗

PubMed1994

IDO mutants cross resistant to type I interferon retain p91-dependent gene induction.

Genetic analyses of mutants have yielded valuable information about p91-associated interferon signal transduction. It was thus discovered that p91 is an essential protein for the induction of both type I and type II interferons. We previously reported the development of ME180 mutants resistant to interferon-gamma because of a signaling defect resulting in the loss of IDO induction. IDO does not respond to type I interferon despite an ISRE-like sequence upstream of the coding region. However, the IDO mutants were found to be cross-resistant to the growth-inhibitory effects of type I interferon. We therefore examined the effects of both types of interferon on interferon-stimulated gene mRNA accumulation and examined alterations in cellular protein introduced by the mutation. The induction of the p91-responsive gene 6-16 was not altered in either of the mutants, and the early-induced gene IRF1 exhibited differences only in the kinetics of mRNA accumulation. The later induced gene, p68, also exhibited different kinetics, possibly reflecting the changes in IRF1. Immunoprecipitated p91 exhibited normal, interferon-induced phosphorylation in both mutants. Two-dimensional gel electrophoresis revealed that the mutant cells contained 20 peptides with altered biochemistry. These results suggest that IDO induction is controlled by a distinct set of proteins not directly correlated with p91 activation.

Cell Division↗

PubMed1994

Direct binding to and tyrosine phosphorylation of the alpha subunit of the type I interferon receptor by p135tyk2 tyrosine kinase.

Binding of type I interferons (IFNs) to their receptors induces rapid tyrosine phosphorylation of multiple proteins, including the alpha and beta subunits of the receptor, the polypeptides that form the transcriptional activator ISGF3 alpha (Stat113, Stat84, and Stat91), and the p135tyk2 and Jak-1 tyrosine kinases. In this report, we demonstrate that the alpha subunit of the type I IFN receptor (IFN-R) corresponds to the product of a previously cloned receptor subunit cDNA and, further, that the p135tyk2 tyrosine kinase directly binds and tyrosine phosphorylates this receptor subunit. Glutathione S-transferase (GST) fusion proteins encoding the different regions of the cytoplasmic domain of the alpha subunit can bind the p135tyk2 contained in human cell lysates. The association between the alpha subunit and Tyk2 was demonstrated by immunoblotting with anti-Tyk2 and antiphosphotyrosine antibodies and by using an in vitro kinase assay. Analogous experiments were then performed with recombinant baculoviruses encoding constitutively active Jak family tyrosine kinases. In this case, p135tyk2, but not Jak-1 or Jak-2 protein, binds to the GST-IFN-R proteins, suggesting that the interaction between these two proteins is both direct and specific. We also demonstrate that Tyk2, from extracts of either IFN alpha-treated human cells or insect cells infected with the recombinant baculoviruses, can catalyze in vitro phosphorylation of GST-IFN-R protein in a specific manner. Deletion mutants of the GST-IFN-R protein were used to localize both the binding and tyrosine phosphorylation site(s) to a 46-amino-acid juxtamembrane region of the alpha subunit, which shows sequence homology to functionally similar regions of other cytokine receptor proteins. These data support the hypothesis that the Tyk2 protein functions as part of a receptor complex to initiate intracellular signaling in response to type I IFNs.

DNA-Binding Proteins↗

PubMed2026

Noncanonical bactericidal activity of teleost type I interferon is conferred by a membrane-targeting C-terminal peptide.

Type I interferons (IFNs) are indispensable antiviral cytokines in nonspecific immunity, yet they play dual roles in bacterial infections in mammals. Recent studies have revealed a subset of strongly cationic type I IFNs possessing potent antimicrobial properties across nonmammalian vertebrates. In this study, we identified a type I IFN gene, CaIFNi, from Cromileptes altivelis that is characterized by a unique triple-disulfide bond architecture. In Vibrio harveyi-challenged models, overexpression of CaIFNi potentiated bacterial clearance capacity in tissues, whereas its knockdown exacerbated bacterial colonization, highlighting its ability to protect the host against bacterial infection in vivo. In vitro assays further confirmed that CaIFNi directly binds to and kills both gram-negative (G-) and gram-positive (G+) bacteria, which first revealed the antibacterial function of new subgroup IFNi within teleost type I IFNs. Furthermore, the α-helical peptide CaIFNi-18 derived from CaIFNi was identified as a novel antimicrobial peptide (AMP) that has broad-spectrum antibacterial efficacy against G- and G+ bacteria and membrane-targeting ability. Further mechanistic studies revealed that CaIFNi has bactericidal effects on both G- and G+ bacteria through membrane depolarization and disruption, alteration of the bacterial ultrastructure, and in vitro binding to genomic DNA. In addition, CaIFNi-18 also has significant in vivo therapeutic efficacy against bacterial infection, highlighting its great potential as an antibacterial agent. Encouragingly, the loss of antibacterial activity in the truncation mutant (rCaIFNiΔ148-165) lacking the CaIFNi-18 segment suggests that this region is essential for the bactericidal function of the full-length protein and likely acts as its core domain. Further computational simulations revealed that the deletion of the CaIFNi-18 region attenuated the interaction between the protein and the bacterial membrane. These findings not only expand the functional scope of type I IFNs beyond their canonical antiviral role but also identify their derivative CaIFNi-18 as both a promising antimicrobial candidate and the essential bactericidal domain of CaIFNi, thereby offering novel therapeutic strategies against bacterial infections in the aquaculture industry and beyond.

Animals↗

PubMed2006

SHP-2 phosphatase negatively regulates the TRIF adaptor protein-dependent type I interferon and proinflammatory cytokine production.

The Toll-like receptor 3 (TLR3) and TLR4-signaling pathway that involves the adaptor protein TRIF activates type I interferon (IFN) and proinflammatory cytokine expression. Little is known about how TRIF pathway-dependent gene expression is regulated. SH2-containing protein tyrosine phosphatase 2 (SHP-2) is a widely expressed cytoplasmic tyrosine phosphatase. Here we demonstrate that SHP-2 negatively regulated TLR4- and TLR3-activated IFN-beta production. SHP-2 inhibited TLR3-activated but not TLR2-, TLR7-, and TLR9-activated proinflammatory cytokine IL-6 and TNF-alpha production. SHP-2 inhibited poly(I:C)-induced cytokine production by a phosphatase activity-independent mechanism. C-terminal domain of SHP-2 directly bound TANK binding kinase (TBK1) by interacting with the kinase domain of TBK1. SHP-2 deficiency increased TBK1-activated IFN-beta and TNF-alpha expression. TBK1 knockdown inhibited poly(I:C)-induced IL-6 production in SHP-2-deficient cells. SHP-2 also inhibited poly(I:C)-induced activation of MAP kinase pathways. These results demonstrate that SHP-2 specifically negatively regulate TRIF-mediated gene expression in TLR signaling, partially through inhibiting TBK1-activated signal transduction.

Adaptor Proteins, Vesicular Transport↗

PubMed2006

Functional assay of type I interferon in systemic lupus erythematosus plasma and association with anti-RNA binding protein autoantibodies.

OBJECTIVE: Peripheral blood mononuclear cells (PBMCs) from patients with systemic lupus erythematosus (SLE) have increased expression of genes typically induced by type I interferon (IFN). However, it has been difficult to identify and quantify the factors responsible for activation of the IFN pathway in SLE. To characterize these mediators, we developed an assay that measures the functional effects of plasma or serum components on the gene expression of cultured target cells. METHODS: WISH epithelial cell line cells were cultured with medium, with recombinant IFNalpha, IFNbeta, or IFNgamma, or with 50% plasma from SLE patients (n = 73), rheumatoid arthritis (RA) patients (n = 19), or healthy donors (n = 30). Real-time quantitative polymerase chain reaction was used to determine WISH cell expression of IFN target genes, including PRKR, IFIT1, IFI44, MX1, and C1orf29 (preferentially induced by IFNalpha) and CXCL9 (Mig) (preferentially induced by IFNgamma). RESULTS: IFNalpha-regulated genes were induced by SLE plasma samples, but not by most of the RA or healthy control plasma samples. The activity in SLE plasma was inhibited >90% by anti-IFNalpha antibody, but not by anti-IFNbeta or anti-IFNgamma antibodies. The expression of each IFNalpha target gene induced by SLE plasma correlated with the expression of that gene studied ex vivo in PBMCs from the same patients and with the titer of anti-RNA binding protein (anti-RBP)-specific autoantibodies. Plasma activity paralleled PBMC expression of IFNalpha-inducible genes over time. CONCLUSION: IFNalpha in SLE plasma is a major stimulus of IFN target gene expression and is related to expression of those genes in PBMCs from SLE patients and to the titer of anti-RBP autoantibodies. These data provide additional support for the view that IFNalpha mediates immune system activation and dysregulation in SLE.

Antibodies↗

PubMed2000

Combination therapy with glatiramer acetate (copolymer-1) and a type I interferon (IFN-alpha) does not improve experimental autoimmune encephalomyelitis.

We sought to determine whether combinations of glatiramer acetate and parenteral or ingested type I interferon were synergistic in experimental autoimmune encephalomyelitis. Glatiramer acetate, subcutaneous murine interferon-alpha, or ingested murine interferon-alpha individually improved clinical scores. In contrast, glatiramer acetate in conjunction with either subcutaneous or ingested interferon-alpha did not improve clinical scores compared with control. These data suggest that clinical trials designed to test a possible synergistic effect of glatiramer acetate and type I interferon in humans should be designed to detect possible adverse effects of this combination of immunomodulatory agents.

Animals↗

PubMed2006

Sensitivity of rabies virus to type I interferon is determined by the phosphoprotein gene.

The growth of a virulent strain of fixed rabies virus, Nishigahara, in mouse neuroblastoma NA cells treated with type I interferon (IFN) was compared with that of a derivative avirulent strain, Ni-CE. Nishigahara strain was slightly sensitive to IFN treatment but still grew more efficiently than did Ni-CE strain in IFN-treated NA cells. Furthermore, a virulent chimeric virus with the phosphoprotein gene from Nishigahara strain in the Ni-CE genome was less sensitive to IFN treatment than was Ni-CE strain, indicating that the IFN sensitivity is determined by the phosphoprotein gene of the virus.

Animals↗

PubMed1998

Scaffold-associated regions in the human type I interferon gene cluster on the short arm of chromosome 9.

Scaffold-associated regions (SARs) function at the level of modeling or shaping the chromatin of DNA into loop domains. We have mapped 36 SARs in the human type I interferon (IFN) gene complex on chromosome 9, band p21-22, to examine the overall structure of this gene complex. A total of 29 strong SARs and 7 weak SARs were mapped to the flanking regions of the different interferon genes. Twenty-two strong SARs mapped to the flanking regions of 13 interferon (IFNA) alpha genes; 2 strong SARs mapped to one interferon omega (IFNW) gene; 2 strong SARs mapped to one interferon alpha pseudogene (IFNAP); and 3 strong SARs mapped to two interferon omega pseudogenes (IFNWP). One weak SAR mapped to the flanking region of one IFNA gene, whereas 6 weak SARs flanked four IFN pseudogenes (P11, P12 P20, P23). The IFN SAR structure was comparable between the BV173 leukemia cell line and the U373 glioma cell line. Analysis of two glioma deletion breakpoint junctions, where breaks occur within and outside the IFN gene cluster, revealed an association with SARs. IFN SARs showed evidence for cooperativity among the SARs, while DNA sequence analysis revealed a series of clustered A-tracts within strong SARs. These data suggest that the IFN genes may be organized into a series of small (2-10 kb) DNA loop domains, with each loop containing a coding region flanked by SARs. In our model, the SAR enrichment and the clustering of A-tracts observed at the SARs within the IFN gene complex represent a higher level of chromatin organization, which may predispose this region to breakage.

Chromatin↗

PubMed2005

Global transcriptional profiling demonstrates the combination of type I and type II interferon enhances antiviral and immune responses at clinically relevant doses.

A role for type II interferon (IFN-gamma) in resolving viral infection is suggested by the correlation of hepatitis C virus (HCV) clearance with enhancement of IFN-gamma-producing activated T cells in the resolution of acute HCV infection. Using vesicular stomatitis virus (VSV), a synergistic direct antiviral effect was documented using IFN-gamma1b and a potent, consensus type I IFN (IFN alfacon-1). Global expression profiling following EC50 exposure to IFN alfacon-1, IFN-gamma1b, or a cocktail of the two allowed the antiviral state to be correlated with induction of a subset of IFN-stimulated genes (ISGs). Genes identified through this analysis corresponded to classic antiviral components, ISGs more recently associated with direct antiviral functions, as well as expressed sequence tags (ESTs) and hypothetical proteins. The magnitude of these antiviral EC50-correlated expression events in human hepatoma (Huh7) cells exposed to clinically relevant doses of IFN alfacon-1, IFN-gamma1b, or a cocktail of the two was also probed because the standard of care for patients with chronic hepatitis C is type I IFN-containing regimens. Relative to type I IFNs used alone, the addition of type II IFN caused enhanced expression not only of many of the genes correlated with the direct antiviral state but also of genes involved in (1) antigen presentation to cytotoxic T lymphocytes (CTLs), (2) macrophage, natural killer (NK), and T helper 1 (Th1) cell recruitment and activation, (3) complement system function, (4) apoptosis, and (5) ISGs with unknown functions. As many of these processes are correlated clinically with resolution of chronic HCV infection, the combined use of these IFNs could display a beneficial effect on viral clearance in patients infected with HCV and other viruses through enhancement of one of these processes or of the direct antiviral state.

Antiviral Agents↗

PubMed2004

Type I interferon as a link between innate and adaptive immunity through dendritic cell stimulation.

Type I interferon (IFN-alpha/beta) is expressed rapidly after infection and plays a key role in innate defense against pathogens. Recent studies have shown that a connection exists between IFN-alpha/beta and antigen-presenting dendritic cells (DCs) at two levels. Firstly, a specific DC precursor, the plasmacytoid pre-DC (p-preDC), was identified as a cell type able to secrete very high amounts of IFN-alpha/beta following stimulation with infectious agents. Secondly, IFN-alpha/beta has been shown to act as a differentiation/maturation factor for DCs. These findings will be discussed in association with evidence indicating that IFN-alpha/beta can enhance and modulate immune responses in vivo. Taken together, the available data suggest that IFN-alpha/beta serves as a link between the innate response to infection and the adaptive immune response.

Animals↗

PubMed1996

Enhancement in vivo of the antiinflammatory and antitumor activities of type I interferon by association with the synthetic immunomodulator murabutide.

The therapeutic efficacy of type I interferon (IFN) has been reported to vary considerably in different indications. The use of the cytokine as adjuvant therapy has been suggested to enhance its efficacy and reduce the toxicity frequently associated with long-term and high-dose administration. In this study, we have assessed the activity of type I IFN in the protection against and treatment of acute hepatitis induced in mice by the administration of concanavalin-A (ConA). At the same time, we have evaluated the efficacy of the synthetic immunomodulator murabutide when administered alone or in combination with type I IFN to protect against ConA hepatitis and in the treatment of tumors in MethA sarcoma-bearing mice. Our results demonstrate a prophylactic effect as well therapeutic effects of type I IFN and of murabutide in the inflammation-mediated model of liver damage. The use of combination therapy presented enhanced efficacy in inhibiting the ConA-induced elevation of plasma transaminases. Both compounds were found to suppress IFN-gamma mRNA accumulation in the livers of ConA treated mice. This activity is discussed with respect to the mechanism of action of the two immunomodulators. In addition, the combination of murabutide with type I IFN exhibited synergistic antitumor activity that was clearly seen in the significant regression of MethA tumors and resulted in almost 50 percent tumor-free mice. The potential clinical application of combination therapies using a cytokine and a safe immunomodulator is analyzed in terms of enhancing the cytokine efficacy and extending its use to new indications.

Acetylmuramyl-Alanyl-Isoglutamine↗

PubMed2002

Transient transfection of mouse fibroblasts with type I interferon transgenes provides various degrees of protection against herpes simplex virus infection.

Type I interferons (IFN) constitute one of the initial and most potent components of the innate immune response against viral infections. While there is only one IFN-beta gene, there are several IFN-alpha genes whose products act through the same receptor calling into question the role of these gene products against viral infection. The focus of the present study was to compare the anti-viral state of cells transiently transfected with different murine type I IFN transgenes including IFN-alpha1, -alpha4, -alpha5, -alpha6, -alpha9, and IFN-beta. Transfected cells produced biologically active IFN ranging from 6 to 46 units/ml. L929 and 3T12.3 cells transfected with the IFN-beta transgene consistently showed a 2-4 fold reduction in herpes simplex virus type 1 (HSV-1) and HSV-2 viral titers compared with cells transfected with the IFN-alpha transgenes which were much less consistent based on HSV species and cell type. Parallel with the reduction in viral titers, cells transfected with the IFN-beta transgene showed the complete absence or significant reduction in viral immediate early, early, and late gene expression. Collectively, the results suggest that the IFN-beta transgene is superior to IFN-alpha transgenes against HSV infection in vitro in part due to a reduction in viral gene expression. These results indicate events downstream of the type I IFN receptor distinguish between the subtypes of IFN-alpha species relative to the activation of genes ultimately responsible for the establishment of the anti-HSV state.

Animals↗

PubMed1998

Sex chromosome linkage of chicken and duck type I interferon genes: further evidence of evolutionary conservation of the Z chromosome in birds.

Type I interferons (IFNs) are a family of proteins that are predominantly expressed in response to viral infection. Two serologically distinct forms of type I IFN, designated ChIFN1 and ChIFN2, have recently been recognized in the chicken. ChIFN1 is encoded by a cluster of ten or more intronless genes, whereas ChIFN2, whose primary sequence is 57% identical, is encoded by a single intronless gene. By fluorescence in situ hybridization we now demonstrate that the genes for ChIFN1 and ChIFN2 are all located on the short arm of the chicken Z chromosome. This assignment was confirmed by results that showed that DNA from male (ZZ) chickens yielded approximately twofold stronger Southern blot signals with ChIFN1 and ChIFN2 hybridization probes than DNA from females (ZW). Attempts to determine differences in IFN production between male and female chickens failed owing to a high degree of variation in virus-induced IFN expression between individuals of both sexes. Sex linkage of IFN genes was also observed in domestic ducks: fluorescence in situ hybridization of duck metaphase chromosomes with a duck type I IFN probe was confined to the terminal region of the long arm of the Z chromosome. Thus, in contrast to mammals, which have their IFN genes on autosomes, birds have the type I IFN genes on the sex chromosome.

Animals↗

PubMed2003

Plasmacytoid dendritic cells induce plasma cell differentiation through type I interferon and interleukin 6.

Dendritic cells (DCs) initiate and control immune responses. Plasmacytoid DCs (pDCs) represent a unique DC subset able to promptly release large amounts of type I interferon (IFN-alphabeta) upon viral encounter. Here we report that depletion of pDCs from human blood mononuclear cells abrogates the secretion of specific and polyclonal IgGs in response to influenza virus. Furthermore, purified pDCs triggered with virus induce CD40-activated B cells to differentiate into plasma cells. Two pDC cytokines act sequentially, with IFN-alphabeta generating non-Ig-secreting plasma blasts and IL-6 inducing their differentiation into Ig-secreting plasma cells. These plasma cells display the high levels of CD38 found on tissue plasma cells. Thus, pDCs are critical for the generation of plasma cells and antibody responses.

Adult↗

PubMed2007

Type I interferon response against viral and non-viral gene transfer in human tumor and primary cell lines.

BACKGROUND: Type I interferon (IFN-alpha/beta) response is one of the major host defence mechanisms against viruses. Some recent reports suggest that IFNs may interfere with the efficacy of both non-viral and virus-vector-mediated therapeutic gene transfer. METHODS: The type I IFN response upon different gene transfer methods in human tumor and primary cell lines was studied by analysing IFN-beta mRNA expression, secretion of type I IFNs and accumulation of IFN-alpha/beta-induced MxA protein (myxovirus resistance protein A). RESULTS: Infection with avirulent Semliki Forest virus A7[74] induced MxA protein accumulation and increased the IFN-beta mRNA level, whereas none of the studied virus vectors (adenovirus, CRAd, lentivirus or AAV) induced IFN response. However, plasmid DNA induced the accumulation of MxA protein when transfected with several commercial transfection reagents. RNA transfection appeared to be an efficient inducer of type I IFN response: replicating alphaviral RNA, eukaryotic total RNA, or mRNA all induced both MxA protein accumulation and IFN-beta expression. siRNA transfection failed to induce MxA response. CONCLUSIONS: The non-viral gene transfer methods have gained more interest in recent years due to their better safety profiles when compared to their viral counterparts. However, the efficiency of non-viral gene transfer is well below those reached by viral vector systems. The type I interferon response induced by non-viral methods may in part contribute to this inefficiency, while most currently used viral gene transfer vectors fail to induce or are able to suppress type I IFN response.

Animals↗

PubMed1997

Type I interferons enhance production of IFN-gamma by NK cells.

In murine models, challenge with different viral and parasitic infection is closely associated with the production of type I interferons (IFN-alpha/beta) and NK cell production of interferon-gamma (IFN-gamma). Therefore, we wished to determine if IFN-alpha/beta had a role in the regulation of NK cell production of IFN-gamma. IFN-alpha/beta alone stimulated low levels of IFN-gamma production by purified populations of IL-2 activated NK cells but in combination with IL-12 resulted in the production of significant levels of IFN-gamma. Interestingly, maximal production of IFN-gamma by NK cells stimulated with IL-2 plus IFN-alpha/beta was dependent on endogenous tumor necrosis factor-alpha (TNF-alpha). Further studies revealed that TNF-alpha enhanced the ability of IFN-alpha/beta to stimulate production of IFN-gamma by NK cells. In contrast to the stimulatory effect of IFN-alpha/beta on NK cell production of IFN-gamma, IFN-alpha/beta inhibited IL-2 induced proliferation of NK cells. This inhibitory effect was not reversed by the addition of neutralizing antibodies specific for IFN-gamma or TNF-alpha. These data demonstrate that the type I interferons enhance NK cell production of IFN-gamma and suggest that they may be important in the regulation of NK cell production of IFN-gamma during infection.

Animals↗