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The short form of the interferon alpha/beta receptor chain 2 acts as a dominant negative for type I interferon action.

We have characterized the functional properties of the short form of the human interferon alpha/beta receptor chain 2 (IFNAR2), denoted IFNAR2.1. IFNAR2.1 contains a shortened cytoplasmic domain when compared with the recently cloned full-length IFNAR2 chain (IFNAR2. 2). We show that IFNalpha8 and IFNbeta1b induce antiviral and antiproliferative activity in mouse cell transfectants expressing the human IFNAR1 chain of the receptor and induce the formation of STAT1/STAT2 dimers in IFN-stimulated response element (ISRE)-dependent gel shift assays. In contrast, coexpression of IFNAR2.1 with IFNAR1 reduces the IFN-induced antiviral, antiproliferative and ISRE-dependent gel shift binding activity conferred by IFNAR1 alone. No antiviral or antiproliferative response to IFN, nor IFN-induced ISRE-dependent gel shift binding activity, was observed when IFNAR2.1 was expressed alone in murine cells. Therefore, IFNAR2.1 acts as a dominant negative for these IFN-induced activities. Our results suggest that IFNAR2.1 represents a nonfunctional version of the full-length chain (IFNAR2.2).

Animals↗

[Effect of type I interferon on the course of endotoxic shock].

The effect of type I interferon (IF) on the course of endotoxic shock was studied by morphological methods. It was found that preliminary (24 hours earlier) injection of preparations of homologous IF (10(3) ME) to ABLb/c and CC57 W mice sensitive to salmonella infection prevented the death of 90% of animals from a lethal toxic dose of the endotoxin or killed salmonellae. Preliminary injection of IF reduced sharply the intensity of morphological changes during all periods of the study. IF mitigates the toxic effect exerted on the cell and tissue structure both by increasing the functional activity of phagocytes, facilitating in this way elimination of the endotoxin from the body, and by increasing cell resistance to the direct effect of the bacterial toxin, which is just what determines its protective antitoxic effect. It was established that IF prevents the development of the most grave changes--thrombosis of the microcirculatory bed of vitally important organs by hindering the development of disseminated intravascular coagulation of blood, which determines the severity and outcome of shock.

Animals↗

Human neutrophils produce macrophage inhibitory protein-1beta but not type i interferons in response to viral stimulation.

Several cell types have been shown to produce type I interferons (IFN). Of human leukocytes, monocytes and especially type 2 dendritic cell precursors (pDC2) seem to be the main producers and also have a wide spectrum of cytokine production. However, neutrophils seem to have a limited capacity for cytokine production but possess efficient defense mechanisms vs. bacterial infection by phagocytosis and degranulation. To determine whether they also have antiviral functions, IFN-alpha and IFN-beta were measured in preparations of pure neutrophils. The capacity of neutrophils to produce type I IFN is controversial. Additionally, macrophage inflammatory protein-1alpha (MIP-1alpha) and MIP-1beta were measured, as they are described to have indirect or direct antiviral activity. As stimulants, active and inactivated Newcastle disease virus (NDV), Sendai virus, and granulocyte colony-stimulating factor (G-CSF) were used. Peripheral blood mononuclear cells (PBMC) from the same donors were highly reactive to viral stimulation, whereas neutrophils failed to produce IFN but produced MIP-1beta in response to NDV. We conclude that neutrophils fail to prevent viral infection by IFN production but probably possess alternative mechanisms, such as secreting MIP-1beta in response to viruses.

Cells, Cultured↗

Molecular detection and identification of type I interferon mRNAs.

The development of a technique for identifying murine type I interferon messenger RNAs is described that involves the following essential steps: (a) the reverse transcription of total RNA extracts using oligo(dT)12-18 as a primer, (b) the amplification of any type I interferon cDNAs produced by polymerase chain reaction, and (c) the identification of interferon subtypes by hybridization of the polymerase chain reaction products to specific oligonucleotides. The technique was used to characterize the expression of the mouse interferon subtypes alpha 1, alpha 4, alpha 5, alpha 6, and beta in murine L929 cells that had been infected with Newcastle disease virus. The data derived from this study are in excellent agreement with earlier RNA protection experiments performed in the same system to characterize expression of the same genes. The present technique has advantages over those used previously, including superior sensitivity, speed, and far smaller input RNA requirements. The technique is not only applicable to other in vitro systems, but is appropriate for use in vivo.

Animals↗

Long-term alpha interferon treatment is effective on anaemia and significantly reduces iron overload in congenital dyserythropoiesis type I.

Interferon has been shown to be an effective treatment of congenital dyserythropoiesis type I (CDA-I), but the optimal dose and the feasibility of this treatment remains to be determined. Here, in a 9-yr follow-up of a single patient, we show that interferon remains active during such a long period. The optimal dose of conventional alpha interferon could be evaluated at 2 million units twice a week. Pegylated interferon could be used as well at a dose of 30 microg/wk. During interferon treatment, serum and erythrocyte ferritin levels decreased progressively, and remained inversely correlated with haemoglobin levels. On repeated liver biopsies, iron overload could be normalized. Low dose interferon is a long-term treatment of CDA-I, and allows a significant decrease in iron overload, that could be interesting even in patients who are only moderately anaemic.

Adult↗

Co-infection by serologically-silent hepatitis B virus may contribute to poor interferon response in patients with chronic hepatitis C by down-regulation of type-I interferon receptor gene expression in the liver.

Intrahepatic mRNA levels of type-I interferon (IFN) receptor genes have been shown to correlate with the clinical efficacy of IFN therapy in patients with chronic hepatitis C. Recently, co-infection by serologically-silent hepatitis B virus (HBV) has been assumed to be associated with the poor IFN response in patients with chronic hepatitis C. The aim of this study was to investigate the relationship between the co-infection of serologically-silent HBV and type-I IFN receptor gene expression in the liver of patients with chronic hepatitis C. The intrahepatic mRNA levels of IFNAR2, one of the two subunits of the type-I IFN receptor, were quantified and compared with both the prevalence of HBV DNA and the hepatitis C virus (HCV) genotype in 45 patients with chronic hepatitis C, who were negative for hepatitis B surface antigen. Co-infection, as evaluated by a nested polymerase chain reaction, was present in 22 patients (48.9%), with dominance of the HCV genotype 1b (65.2%) over genotype 2a (31.8%). Co-infection was associated with lower IFNAR2 mRNA levels, higher levels of serum HCV RNA, and a poor IFN response, regardless of the HCV genotype. The findings suggest the possibility that co-infection by serologically-silent HBV is one of the factors that can lead to an unfavorable IFN response in chronic hepatitis C by down-regulation of IFN receptor gene expression in the liver.

Adult↗

Negative regulation of type I interferon signaling: facts and mechanisms.

Initially described for their antiviral activities, type I Interferons are now recognized as central regulatory elements of the immune response, primarily for their effect on the differentiation of monocytes into dendritic cells and osteoclasts. They are routinely used in clinic for the treatment of several diseases, including viral hepatitis, multiple sclerosis and several forms of cancer. Interferons are however not devoid of toxic effects when high doses are administered to patients, indicating that interferon action must be timely and spatially down regulated. We review here the molecular mechanisms which have been described to shut off the interferon initiated signals.

Animals↗

Effect of alpha 2-interferon on hairy cells and cell lines: a role for type I interferon receptors and RNA synthesis.

The binding of alpha 2-interferon to highly purified plasma membrane proteins of malignant human lymphoid cells was assessed by Western Blotting. The human hairy cell leukemia cell line JOK-1 revealed three major alpha-interferon binding proteins with molecular weights of 120, 100, and 32 kD. Pretreatment of JOK-1 cells with alpha-interferon in vitro results in a disappearance of these proteins, which is in concordance with receptor down-regulation on JOK-1 cells. In a case of T chronic lymphocytic leukemic (CLL), a differential binding pattern of two proteins with 100 and 85 kD was observed, whereas a case of B-CLL did not yield any signal detection. In addition, mononuclear cells from patients with hairy cell leukemia and CLL were found to differ with respect to the in vitro incorporation of nucleic acid precursors. alpha 2-Interferon enhances [3H] uridine incorporation into hairy cells, whereas this phenomenon can be detected in CLL cells only to a much lesser extent.

DNA, Neoplasm↗

Affinity-matured B cell responses neutralizing type-I interferons underlie severe viral infections.

Autoantibodies neutralizing type-I interferons (AAN-I-IFNs) emerge as global, common, and strong determinants of a growing number of severe viral diseases. We report that AAN-I-IFNs+ patients with life-threatening COVID-19 pneumonia harbor circulating type-I IFN-specific B cells indistinguishable from patients bearing T cell tolerance defects of genetic origin. This autoimmune response mobilizes a highly diverse and stable circulating B cell response that is detected prior to severe viral infection and acquires high affinity and neutralization potential to type-I IFNs through extended somatic hypermutation. X-ray crystallography and AlphaFold3 structural analysis of hundreds of patient-derived monoclonal antibodies reveals the extended breadth of this response, targeting three major B cell epitopes covering all facets of type-I IFNs. These findings support a model in which a germinal-center-derived memory B cell response directed against type-I IFNs is established before severe viral infection, providing a core mechanism linking T cell tolerance defect to pathogenic AAN-I-IFNs underlying severe viral diseases.

Humans↗

Type I interferons and limitin: a comparison of structures, receptors, and functions.

The type I interferon (IFN) family includes IFN-alpha, IFN-beta, IFN-pi, and IFN-tau. These molecules are clustered according to sequence homologies, use of the same cell surface receptor, and similar functions. IFN-alpha and IFN-beta have a globular structure composed of five a-helices. Their receptors, IFNAR1 and IFNAR2, belong to the class II cytokine receptor family for a-helical cytokines. Information about structure-function relationships between these and other IFNs is being provided by comparative sequence analysis, reference to a prototypic three-dimensional structure, analysis with monoclonal antibodies, construction of hybrid molecules and site directed mutagenesis. While much remains to be done, it should someday be possible to understand differences among IFNs in terms of how they interact with their corresponding receptors. Our recently identified IFN-like molecule, limitin, has weak sequence homology to IFN-alpha, IFN-beta, and IFN-omega and displays its biological functions through the same IFN-alpha/beta receptors. While limitin has antiproliferative, immunomodulatory, and antiviral effects like IFN-alpha and IFN-beta, it is unique in lacking influence on myeloid and erythroid progenitors. Further analysis of this functionally unique cytokine should be informative about complex IFN-receptor interactions. Furthermore, a human homologue or synthetic variant might be superior for clinical applications as an IFN without myelosuppressive properties.

Amino Acid Sequence↗

[Mechanism of action of interferon-alpha 2 in hairy cells and lymphoblastoid cell lines: the significance of type I interferon receptors and RNA synthesis].

Lymphoblastoid cells were subjected to Western Blot analysis for detection of Interferon-alpha-binding proteins. JOK-1 cells--a human hairy cell leukemia line--revealed three proteins with apparent molecular weights of 120, 100 and 32 kD, respectively. Down-regulation of the receptor was observed. A differential binding pattern of two proteins (100 and 85 kD) was observed in T-CLL, whereas no signal detection was achieved in B-CLL. Mononuclear cells from 6 patients with hairy cell leukemia and 6 patients with CLL were found to differ significantly in terms of nucleic acid precursor incorporation.

Blotting, Western↗

Expression of toll-like receptors and type 1 interferon specific protein MxA in biliary atresia.

Viral infection and type I interferon have been implicated in the pathogenesis of biliary atresia (BA), but the expression of toll-like receptors (TLRs) that recognize viruses, as well as of type 1 interferon specific signaling molecules are still unknown in BA. Fresh liver tissues were obtained from patients in early and late stage of BA and from patients with choledochal cyst (CC), as well as from normal controls receiving liver resection for benign lesion other than cholestasis or fibrosis. Archived liver tissues from patients with neonatal hepatitis (NH) were obtained for immunohistochemical studies. TLR2, 3, 4, 7 and 9 that recognized Gram-positive bacteria, double-stranded RNA virus, lipopolysaccharide, single-stranded RNA virus and DNA virus, respectively, were studied. Real-time quantitative reverse transcription polymerase chain reaction (QRT-PCR) was used to quantitate TLR, type I interferon specific molecule MxA, interleukin-6 (IL-6) and IL-8 mRNA expression and immunohistochemistry for TLR 7 and MxA protein staining. These results show that there were significantly higher TLR7 and lower TLR3 and TLR9 mRNA expression in early stage of BA than in CC. MxA mRNA expression was also significantly higher in early stage of BA and in CC than in late stage of BA. Immunoreactive TLR7 and MxA staining was higher in early stage of BA than in late stage of BA, NH and CC, which was associated with significantly higher IL-8 mRNA expression in BA than in CC. The results implicate involvement of TLRs, particularly TLR7, and type 1 specific interferon signaling in the pathogenesis of BA, especially in early stage, which is associated with upregulation of inflammatory cytokines IL-8.

Adolescent↗

Early induction of proinflammatory cytokine and type I interferon mRNAs following Newcastle disease virus, poly [rI:rC], or low-dose LPS challenge of the mouse.

Numerous cytokines induce symptoms characteristic of the flu syndrome common to acute viral infections. To better characterize the cytokine mRNA profile associated with the early phase of this syndrome, we examined the induction of cytokine mRNAs in spleens of mice 1, 2, and 4 h following intraperitoneal inoculation of Newcastle disease virus (NDV). The reverse transcriptase-polymerase chain reaction was used to detect mRNAs for mouse proinflammatory cytokines [interleukin (IL)-1 alpha, IL-1 beta, IL-6, tumor necrosis factor-alpha (TNF-alpha), macrophage colony-stimulating factor (M-CSF), and interferon (IFN)-gamma] and type I IFNs (IFN-alpha 4 and IFN-beta). We observed a rapid (within 2 h) induction of most of these cytokine mRNAs in the mouse spleen following challenge with live NDV or the viral stimulant poly[rI:rC]. IL-1 beta, M-CSF, and IFN-gamma mRNAs were also induced by heat-inactivated NDV, suggesting the possibility of endotoxin contamination of the virus (confirmed by Limulus lysate assay). Examination of cytokine induction by comparable doses of lipopolysaccharide indicated that endotoxin contamination could account for the cytokine mRNA-inducing activity of the heat-inactivated virus. These studies point to a critical control (heat-inactivated virus) for viral cytokine studies. In addition, they indicate that certain cytokine mRNAs (IL-1 alpha, IL-6, M-CSF, IFN-gamma, IFN-alpha, and IFN-beta) are rapidly induced in the spleen when live virus is inoculated intraperitoneally, independently of contaminating endotoxin.

Animals↗

[The first answer to viral infections: type I interferon].

The interferon system is part of the innate immune system in vertebrates. It represents the first line of host defence against viral infections. Virus entry triggers intracellular signalling pathways which lead to the secretion of soluble factors such as interferons and other cytokines. Interferons signal to neighbouring cells that a viral infection has occurred and induce an "antiviral state" resulting in inhibition of virus replication. The first recombinant interferons were produced in the 1980ies and were considered to be a major breakthrough. At present, interferons are routinely used in the therapy of certain viral and autoimmune diseases as well as for neoplastic disorders in man. In 2001 the first interferon preparation for veterinary use was licensed in the European Union. This review summarises the molecular mechanisms of the interferon system and the viral counteractions. The current type I interferon therapies in humans are described and an overview of recent clinical studies in veterinary medicine, including cat, dog, horse, cow, sheep, pig, and poultry, is given. We review the potential application of interferons and arguments in favor or against its therapeutic use in veterinary medicine.

Animals↗

Expression and signaling specificity of the IFNAR chain of the type I interferon receptor complex.

The IFNAR chain of the type I interferon (IFN) receptor (IFNIR) undergoes rapid ligand-dependent tyrosine phosphorylation and acts as a species-specific transducer for type I IFN action. Using the vaccinia/T7 expression system to amplify IFNAR expression, we found that human HeLa-S3 cells transiently express high levels of cell surface IFNAR chains (approximately 250,000 chains per cell). Metabolic labeling and immunoblot analysis of transfected HeLa cells show that the IFNAR chain is initially detected as 65-kDa and 98-kDa precursors, and then as the 130-kDa mature protein. Due to variation in N-glycosylation, the apparent molecular mass of the mature IFNAR chain varies from 105 to 135 kDa in different cells. IFNIR structure was characterized in various human cell lines by analyzing 125I-labeled IFN cross-linked complexes recognized by various antibodies against IFNIR subunits and JAK protein-tyrosine kinases. Precipitation of cross-linked material from Daudi cells with anti-IFNAR antibodies showed that IFNAR was present in a 240-kDa complex. Precipitation of cross-linked material from U937 cells with anti-TYK2 sera revealed a 240-kDa complex, which apparently did not contain IFNAR and was not present in IFN-resistant HEC1B cells. The tyrosine phosphorylation and down-regulation of the IFNAR chain were induced by type I IFN in several human cell lines of diverse origins but not in HEC1B cells. However, of type I IFNs, IFN-beta uniquely induced the tyrosine phosphorylation of a 105-kDa protein associated with the IFNAR chain in two lymphoblastoid cell lines (Daudi and U266), demonstrating the specificity of transmembrane signaling for IFN-beta and IFN-alpha through the IFNAR chain.

Animals↗

Impaired induction of type II interferon in tumor-bearing mice.

The response of mice to type II interferon inducers such as purified protein derivative of tuberculin or OK-432 was significantly impaired after either the implantation of tumor cells or the injection of cell-free tumor ascitic fluids. Complete inhibition of type II interferon induction occurred in 3 to 5 days. This inhibitory effect persisted until the death of mice implanted with tumors or for 7 days after i.p. injection of 0.2 ml of tumor ascitic fluid. The inhibitory activity was seen even with 0.2 ml of the 10,000-fold dilution of the fluid and with its filtrate passed through a Diaflo UM-10 membrane (greater than 10,000-dalton exclusion), However, such tumor ascitic fluids did not affect the induction of type I interferon in mice by polyriboinosinic-polyribocytidylic acid or tilorone-HCl. Moreover, adjuvant-induced nontumorous ascitic fluid had no inhibitory activity. These results indicate that the in vivo induction of type II interferon is specifically impaired by tumor-mediated factor(s) with molecular weights of less than 10,000.

Animals↗

The in vitro expression patterns of individual type I interferon genes in Newcastle disease virus infected murine splenocytes and fibroblasts.

Murine type I interferon levels present in mice sera following Newcastle disease virus infections are influenced by the If-1 locus. Sera interferon levels in C57BL/6 mice (If-1h allele) are 10- to 15-fold higher than in BALB/c mice (If-1(1) allele). The B6.C-H-28c strain, which carries BALB/c If-1(1) allele on C57BL/6 genomic background, has low interferon levels in sera. This study examined the expression of interferon alpha 1, alpha 4, alpha 5, alpha 6, alpha 9 and beta mRNAs at 7 hr after Newcastle disease virus infection of primary cells (splenocytes and mouse embryo fibroblasts) from C57BL/6, B6.C-H-28c and BALB/c mouse genotypes. Total RNA from these cells was reverse transcribed and all known type I interferon subtypes were amplified. The products were identified by differential hybridization to a panel of subtype specific oligonucleotides. The results show that the pattern of interferon subtypes examined in splenocytes did not differ between If-1h and If-1(1) allele carrying C57BL mice. However, when the genotype was different (BALB/c splenocytes) the pattern of type I interferon mRNAs seen was altered. This genotype-dependent expression was also seen in newcastle disease virus infected fibroblasts. Within a given mouse strain, there were also differences in the subtype response patterns detected in fibroblasts compared with those seen in splenocytes. In conclusion, the present study indicates that mouse genotype appears to be a major determinant of the subtype response pattern seen and tissue specific pattern differences are present within a given mouse genotype.

Animals↗

Type I Interferon Signature is Associated With Lung Disease, Drug-Associated Immune Reactions, and Genetic Variation in Interferon-Linked Pathways in Still Disease.

OBJECTIVE: To evaluate the relationship across type I interferon (IFN-I)-stimulated gene (ISG) expression, Still disease, and the development of lung disease (LD) and drug-associated immune reactions (DAIR) to interleukin-1 (IL-1) and/or IL-6 inhibitors. METHODS: Whole blood ISG expression was quantified by NanoString array. ISG-28 scores were calculated in consecutive patients with Still or Still-like disease. Exome sequencing with family-based variant prioritization identified candidate genes harboring rare candidate causative variants. Lists of candidate genes were subjected to functional enrichment analysis. RESULTS: Among 57 patients (32 children, 25 adults), 16 had elevated ISG-28 scores. This group exhibited higher prevalence of LD (0.44 vs 0.1, P = 0.007) and DAIR (0.63 vs 0.17, P = 0.003) and lower IL-6 inhibitor use (0 vs 0.25, P = 0.048) compared to others. No significant differences were found in the rates of macrophage activation syndrome, active disease, elevated IL-18, or current IL-1 inhibition. The combination of HLA-DRB1*15 with high ISG-28 scores is associated with LD and DAIR with high specificity, whereas absence of both biomarkers had high negative predictive value. Candidate genes from high ISG-28 individuals were enriched in IFN-related pathways, including autophagy, IFN-I production, toll-like receptor signaling, macrophage activation, cytoskeletal organization, and responses to stress. CONCLUSION: High IFN-I expression correlates with LD and DAIR in Still disease, linked to rare genetic variation in immune pathways. Combining high ISG-28 with HLA-DRB1*15 significantly improves post hoc stratification of patients for these complications. If prospectively validated, these findings may guide molecular risk assessment and targeted therapies, including IFN-I directed treatments in Still disease with IFN-I signature.

Humans↗