Radiation inactivation of human gamma-interferon: cellular activation requires two dimers

Cloning and characterization of type IV interferon from black carp Mylopharyngodon piceus

From mammals to fish, interferons (IFNs) play vital roles in the immune response. In this study, a newly identified type IV interferon (bcIFN-υ) from black carp (Mylopharyngodon piceus) has been cloned and characterized. The CDS of bcIFN-υ consists of 489 nucleotides, encoding 163 amino acids, with the first 20 amino acids predicted to be the signal peptide region. The immunoblot and immunofluorescence assays verified that bcIFN-υ was a secreted cytokine. qPCR analysis and reporter assay demonstrated that bcIFN-υ participated in innate immune defense and activated the transcription of fish ISRE promoter under spring viremia of carp virus (SVCV) stimulation. Additionally, compared with control group, EPC cells transfected with bcIFN-υ or incubated with the bcIFN-υ-containing conditioned media before SVCV infection showed greatly enhanced antiviral activity, and the transcription levels of MX1, PKR, ISG15 and Viperin genes were significantly increased. The subsequential co-immunoprecipitation assay identified the interaction between bcIFN-υ proteins. Collectively, our data conclude that bcIFN-υ is a kind of secretory protein with self-interaction and triggering the expression of downstream ISGs to enhance the antiviral activity of host cells.

Acute exacerbation of interstitial lung disease associated with rheumatic disease

Interstitial lung disease (ILD) is a cause of morbidity and mortality in patients with rheumatic diseases, such as connective-tissue diseases, rheumatoid arthritis and systemic vasculitis. Some patients with ILD secondary to rheumatic disease (RD-ILD) experience acute exacerbations, with sudden ILD progression and high mortality during or immediately after the exacerbation, and a very low 1-year survival rate. In the ILD subtype idiopathic pulmonary fibrosis (IPF), an acute exacerbation is defined as acute worsening or development of dyspnoea associated with new bilateral ground-glass opacities and/or consolidations at high-resolution CT, superimposed on a background pattern consistent with fibrosing ILD. However, acute exacerbation in RD-ILD (AE-RD-ILD) currently has no specific definition. The aetiology and pathogenesis of AE-RD-ILD remain unclear, but distinct triggers might include infection, mechanical stress, microaspiration and DMARD treatment. At this time, no effective evidence-based therapeutic strategies for AE-RD-ILD are available. In clinical practice, AE-RD-ILD is often empirically treated with high-dose systemic steroids and antibiotics, with or without immunosuppressive drugs. In this Review, we summarize the clinical features, diagnosis, management and prognosis of AE-RD-ILD, enabling the similarities and differences with acute exacerbation in IPF to be critically assessed.

The immunomodulatory effects of ginsenoside derivative Rh2-O on splenic lymphocytes in H22 tumor-bearing mice is partially mediated by TLR4

PURPOSE

Previously, we reported the octyl ester derivative of ginsenoside Rh2 (Rh2-O) had better antitumor and immunomodulatory effects than Rh2 in H22 tumor-bearing mice. Therefore, this study further explored the effects of Rh2-O on splenic lymphocytes in H22 tumor-bearing mice and the underlying mechanism.

METHODS

Wild type and Tlr4^-/- mice were selected to establish the H22 tumor-bearing mice model. After the treatment of Rh2-O (10 mg/kg by gavage) for 15 days, the sizes of tumor were measured. Subsequently, the splenic lymphocytes were isolated and the activities (eg. cell proliferation, cytotoxicity and cytokine secretion) were evaluated. Then, the proteins and mRNA expression levels of TRAF6 and NF-ĸB p65 in splenic lymphocytes were examined.

RESULTS

The results showed that Rh2-O administration enhanced the proliferative capacity and cytotoxicity of splenic lymphocytes, and the effects were Tlr4-associated. Compared to WT mice, the up-regulation of cytokines secretion (eg. IFN-γ, IL-2 and IL-4) in isolated splenic lymphocytes after Rh2-O administration was lower in Tlr4^-/- mice. Moreover, the results showed Rh2-O increased the expression of TRAF6 and the level of endonuclear NF-ĸB p65, which was inhibited in Tlr4^-/- mice (P < 0.05).

CONCLUSION

Rh2-O could exert immunomodulatory effects on splenic lymphocytes with the partial participation of TLR4 in H22 tumor-bearing mice.

Intrauterine inhibition of chemokine receptor 4 signaling modulates local and systemic inflammation in ovine pregnancy

PROBLEM

Chemokines help coordinate inflammation within the fetal-maternal microenvironment during gestation. The chemokine CXCL12 signaling through its receptor CXCR4 regulates inflammatory activity, but this phenomenon is not well understood during pregnancy, and there are no reports exploring the role of this pair in peripheral immune tolerance during gestation. Herein, we hypothesize that intrauterine CXCL12-CXCR4 signaling governs local and systemic immunomodulatory dynamics during early gestation in ewes.

METHOD OF STUDY

Osmotic pumps were surgically installed for intrauterine infusion of a CXCR4 inhibitor, AMD3100, beginning on day 12 post-breeding in sheep. Endometrial tissues were collected on day 35 of gestation and evaluated for inflammatory potential, Akt pathway activation, and autophagy induction. Demonstrative of peripheral immune activity, levels of select cytokines were assessed in daily blood samples collected throughout the study, as well as in corpus luteum and spleen on day 35.

RESULTS

Anti-inflammatory IL10 was primarily localized to endometrial glandular epithelium with lower abundance when CXCR4 was antagonized. Inhibition of CXCR4 at the fetal-maternal interface resulted in less activation of Akt in endometrium, while evidence of autophagy induction was greater. Corpora lutea from ewes receiving intrauterine AMD3100 exhibited lower interferon-gamma (IFNG) expression. Blood inflammatory potential was differentially altered in a temporal fashion throughout infusion. IL10 abundance in spleen was greater following CXCR4 inhibition at the fetal-maternal interface, while IFNG was less.

CONCLUSION

Intrauterine CXCL12-CXCR4 signaling governs endometrial and systemic inflammation; disruption of this axis may have detrimental impacts on offspring and maternal health.

IFN-γ: A cytokine at the right time, is in the right place

Interferon gamma has long been studied as a critical mediator of tumor immunity. In recent years, the complexity of cellular interactions that take place in the tumor microenvironment has become better appreciated in the context of immunotherapy. While checkpoint inhibitors have dramatically improved remission rates in cancer treatment, IFN-γ and related effectors continue to be identified as strong predictors of treatment success. In this review, we provide an overview of the multiple immunosuppressive barriers that IFN-γ has to overcome to eliminate tumors, and potential avenues for modulating the immune response in favor of tumor rejection.

Development of a manual self-assembled colloidal gold nanoparticle-immunochromatographic strip for rapid determination of human interferon-γ

Interferons (IFNs) play a role in inhibition of tumor growth and participate in immunoreactions. Among IFNs, interferon-γ (IFNγ) is one of the most important therapeutic proteins and its immunodulation ability is better than that of other types. The objective of this study is to develop a manual self-assembled colloidal gold nanoparticle-immunochromatographic strip for human IFNγ using anti-human IFNγ polyclonal and monoclonal antibodies. Colloidal gold with a 25 nm diameter was made from chloroauric acid (HAuCl4), and labeled on anti-IFNγ mAbs as a chrominance reagent. A good linear relationship existed between the pixel intensity and the human IFNγ concentrations from 10-1000 ng mL(-1) in mouse serum and buffer, respectively, the regression equation was Y = 0.159logX + 0.0648, R(2) = 0.992 in mouse serum; Y = 0.294logX + 0.091, R(2) = 0.9969 in phosphate buffer by this proposed strip. Moreover, in the determination for mouse serum samples no cross-reaction occurred and the detection time was approximately 10 minutes. The shelf life of the strip was above 28 days at room temperature. The major advantages of the manual operation model were no expensive instruments and less reagents required. This proposed strip was highly specific, economic, convenient, and no machine was needed in clinical diagnosis.

IL-28A, IL-28B, and IL-29: promising cytokines with type I interferon-like properties

IL-28A, IL-28B and IL-29 (also designated type III interferons) constitute a new subfamily within the IL-10-interferon family. They are produced by virtually any nucleated cell type, particularly dendritic cells, following viral infection or activation with bacterial components, and mediate their effects via the IL-28R1/IL-10R2 receptor complex. Although IL-28/IL-29 are closer to the IL-10-related cytokines in terms of gene structure, protein structure, and receptor usage, they display type I interferon-like anti-viral and cytostatic activities. Unlike type I interferons, the target cell populations of IL-28/IL-29 are restricted and mainly include epithelial cells and hepatocytes. These properties suggest that IL-28/IL-29 are potential therapeutic alternatives to type I interferons in terms of viral infections and tumors. This review describes the current knowledge about these cytokines.

Modulation of the activation of Stat1 by the interferon-gamma receptor complex

The activation of Stat1 by the interferon-gamma (IFN-gamma) receptor complex is responsible for the transcription of a significant portion of IFN-gamma induced genes. Many of these genes are responsible for the induction of an apoptotic state in response to IFN-gamma. In the absence of Stat1 activation, IFN-gamma instead induces a proliferative response. Modifying Stat1 activation by IFN-gamma may have pharmacological benefits. We report that the rate of activation of Stat1 can be altered in HeLa cells by overexpressing either the IFN-gammaR1 chain or the IFN-gammaR2 chain. These alterations occur in hematopoietic cell lines: Raji cells and monocytic cell lines, which have average and above-average IFN-gammaR2 surface expression, activate Stat1 similarly to HeLa cells and HeLa cells overexpressing IFNgammaR2, respectively. The rapid Stat1 activation seen in HeLa cells can be inhibited by overexpressing a chimeric IFN-gammaR2 chain that does not bind Jak2 or (when high concentrations of IFN-gamma are used) by overexpressing IFN-gammaR1. These data are consistent with a model in which the recruitment of additional Jak2 activity to a signaling complex accelerates the rate of Stat1 activation. We conclude that the rate of activation of Stat1 in cells by IFN-gamma can be modified by regulating either receptor chain and speculate that pharmacological agents which modify receptor chain expression may alter IFN-gamma receptor signal transduction.

Interferons, interferon-like cytokines, and their receptors

Recombinant interferon-alpha (IFN-alpha) was approved by regulatory agencies in many countries in 1986. As the first biotherapeutic approved, IFN-alpha 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-alpha, IFN-beta, IFN-epsilon, IFN-kappa, IFN-omega, IFN-delta, IFN-tau, IFN-gamma, 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.

Hypoxia-induced down-regulation of CYP1A1/1A2 and up-regulation of CYP3A6 involves serum mediators

1. Acute moderate hypoxia modifies the catalytic activity and expression of certain isoenzymes of hepatic cytochrome P450 (P450). The aim of this study was to document whether hypoxia affects hepatic P450 directly or through the release of serum mediators. 2. Rabbits were subjected to a FiO(2) of 8% for 48 h, sacrificed, and serum and hepatocytes were isolated; hepatocytes from control and rabbits with hypoxia were incubated with serum from control and hypoxic rabbits for 4 and 24 h, and total P450 content, CYP1A1, 1A2 and 3A6 activities and expressions were assessed. Sera were fractionated by size exclusion chromatography and fractions tested for their ability to modify activity and amount of P450, and serum mediators were identified through neutralization experiments. 3. Total serum and fractions with proteins of 15-23 and 65-94 kDa of M(r) reduced P450 content and expression of CYP1A1, 1A2 and 3A6, as well as CYP1A1, 1A2 and 3A6 mRNA. Total serum and the fraction with 32-44 kDa proteins increased CYP3A6 activity and protein and mRNA. The serum mediators implicated in the decrease in activity and expression of CYP1A1, 1A2 and 3A6 were interferon-gamma (IFN-gamma), interleukin-1beta (IL-1beta) and IL-2. Erythropoietin (Epo) was partly responsible for the increase in P450 content and CYP3A6 expression. 4. In conclusion, acute moderate hypoxia diminishes the activity and expression of CYP1A1, 1A2 and CYP1A1, 1A2 mRNA, and increases CYP3A6 protein, activity and CYP3A6 mRNA. Several mechanisms contribute to these changes in P450, among them the release of cytokines acting as serum mediators.

Effects of high-energy electrons and gamma rays directly on protein molecules

High-energy electrons and gamma rays ionize molecules at random along their trajectories. In each event, chemical bonds are ruptured, releasing radiolytic products that diffuse away. A solution of macromolecules is mostly water whose principal radiation products are H(+) and OH(-). These can diffuse to and react with macromolecules; this indirect action of radiation is responsible for 99.9% of the damage to proteins. In frozen samples, the ionizations still occur randomly and water is still the principle molecular target, but diffusion of radiation products is limited to only a very small distance. At very low temperatures, essentially all the radiation damage to macromolecules is due to primary ionizations occurring directly in those molecules. Therefore, proteins in frozen solutions are only 10(-3) to 10(-4) as sensitive to radiation as in the liquid state. Every molecule that suffered a direct ionization is destroyed; the only surviving molecules are those that escaped ionization. The survival of frozen proteins after irradiation is a direct measure of the mass of the active structures and independent of the presence of other proteins.

Valency or wählency: is the epitope diversity of the B-cell response regulated or chemically determined?

For almost a century, the humoral immune response has been monitored principally by the measurement of antibody concentrations, although antibody affinity and isotype have also long been acknowledged as critical to their biological activity. In this report, it is argued that these measures alone may provide a poor measure of the activity of serum antibodies. A B-cell response that is directed against multiple epitopes on a protein can form immune complexes bearing multiple antibody molecules. This is essential for the efficient initiation of processes such as the complement cascade and the activation of leucocytes via Fc receptors. These processes can be dramatically enhanced when B cells target a greater number of epitopes on any antigen. Evidence that the epitope diversity of an immune response may vary between individuals, and that it may vary in an individual over time, is reviewed. This variability is likely to be influenced by a number of host-specific factors in addition to antigen chemistry. The appropriateness of the chemically deterministic term 'antigen valency' to describe the number of epitopes recognized by an individual's B-cell response is discussed, and the term 'wählency' to emphasize the situational nature of B-cell epitopes is introduced.

Crystal structure of the IL-10/IL-10R1 complex reveals a shared receptor binding site

Interleukin 10 (IL-10) is a dimeric cytokine that plays a central role in suppressing inflammatory responses. These activities are dependent on the interaction of IL-10 with its high-affinity receptor (IL-10R1). This intermediate complex must subsequently recruit the low-affinity IL-10R2 chain before cell signaling can occur. Here we report the 2.9 A crystal structure of IL-10 bound to a soluble form of IL-10R1 (sIL-10R1). The complex consists of two IL-10s and four sIL-10R1 molecules. Several residues in the IL-10/sIL-10R1 interface are conserved in all IL-10 homologs and their receptors. The data suggests that formation of the active IL-10 signaling complex occurs by a novel molecular recognition paradigm where IL-10R1 and IL-10R2 both recognize the same binding site on IL-10.

The human interferon alpha species and receptors

Interferon (IFN) was approved by the U.S. Food and Drug Administration on June 5, 1986. As the first biotherapeutic approved, IFN-alpha paved the way for development of many other cytokines and growth factors. Nevertheless, we have just touched the surface of understanding the multitude of human IFNs. This paper reviews the history of the purification of human leukocyte IFN and key aspects of our current state of knowledge of human interferon alpha genes, proteins, and receptors.

The type I interferon receptor: structure, function, and evolution of a family business

Recent results indicate that coherent models of how multiple interferons (IFN) are recognized and signal selectively through a common receptor are now feasible. A proposal is made that the IFN receptor, with its subunits IFNAR-1 and IFNAR-2, presents two separate ligand binding sites, and this double structure is both necessary and sufficient to ensure that the different IFN are recognized and can act selectively. The key feature is the duplication of the extracellular domain of the IFNAR-1 subunit and the configurational geometry that this imposes on the intracellular domains of the receptor subunits and their associated tyrosine kinases.

The glycosylation heterogeneity of recombinant human IFN-gamma

The cloning of the cDNA for human interferon-gamma (IFN-gamma) has resulted in its expression in Escherichia coli, baculovirus-infected insect cells, Chinese hamster ovary (CHO) cells, and the mammary gland of transgenic mice. Large quantities of highly purified recombinant IFN-gamma have been generated, aided by the use of highly specific neutralizing monoclonal antibodies, with a view to its production as a human therapeutic protein. The primary source of structural heterogeneity for IFN-gamma during its production in mammalian expression systems is glycosylation, which can profoundly affect the three-dimensional structure of a glycoprotein and its biological function. A number of analytical approaches have been developed recently to allow a detailed analysis of the carbohydrate structures associated with IFN-gamma, the principal advances being in the areas of capillary electrophoresis and mass spectrometry. The implementation of these high-resolution analytical tools to determine the glycosylation profile of IFN-gamma makes it one of the best characterized recombinant glycoproteins. Recombinant human IFN-gamma acts as a model secretory glycoprotein, typifying the intrinsic glycosylation processing events associated with production of a potential therapeutic glycoprotein.

Identification and functional characterization of a second chain of the interleukin-10 receptor complex

Interleukin-10 (IL-10) is a pleiotropic cytokine which signals through a specific cell surface receptor complex. Only one chain, that for ligand binding (IL-10Ralpha or IL-10R1), was identified previously. We report here that, although human IL-10 binds to the human IL-10R1 chain expressed in hamster cells, it does not induce signal transduction. However, the co-expression of CRFB4, a transmembrane protein of previously unknown function belonging to the class II cytokine receptor family, together with the IL-10R1 chain renders hamster cells sensitive to IL-10. The IL-10:CRFB4 complex was detected by cross-linking to labeled IL-10. In addition, the IL-10R1 chain was able to be co-immunoprecipitated with anti-CRF antibody when peripheral blood mononuclear cells were treated with IL-10. These results demonstrate that the CRFB4 chain is part of the IL-10 receptor signaling complex. Thus, the CRFB4 chain, which we designate as the IL-10R2 or IL-10Rbeta chain, serves as an accessory chain essential for the active IL-10 receptor complex and to initiate IL-10-induced signal transduction events.

Other kinases can substitute for Jak2 in signal transduction by interferon-gamma

Each cytokine which utilizes the Jak-Stat signal transduction pathway activates a distinct combination of members of the Jak and Stat families. Thus, either the Jaks, the Stats, or both could contribute to the specificity of ligand action. With the use of chimeric receptors involving the interferon gamma receptor (IFN-gammaR) complex as a model system, we demonstrate that Jak2 activation is not an absolute requirement for IFN-gamma signaling. Other members of the Jak family can functionally substitute for Jak2. IFN-gamma can signal through the activation of Jak family members other than Jak2 as measured by Statlalpha homodimerization and major histocompatibility complex class I antigen expression. This indicates that Jaks are interchangeable and indiscriminative in the Jak-Stat signal transduction pathway. The necessity for the activation of one particular kinase during signaling can be overcome by recruiting another kinase to the receptor complex. The results may suggest that the Jaks do not contribute to the specificity of signal transduction in the Jak-Stat pathway to the same degree as Stats.