Regulation of Murine Class I Genes by Interferons is Controlled by Regions Located Both 5' and 3' to the Transcription Initiation Site

Interferons regulate the expression of a large number of mammalian genes, including the major histocompatibility antigen genes. To investigate the mechanisms involved in interferon action, we have analyzed the ability of murine H-2Ld and H-2Dd DNA sequences to control the responses to interferon. The results indicate that interferon regulation of class I gene expression is complex and involves at least two mechanisms that are dependent on class I sequences located upstream and downstream to the transcription initiation site. In transfected mouse L cells, both of these regions are required for full enhancement of class I gene expression, with the major portion of the response controlled by the sequences located 3' to the transcription initiation site. The fine-mapping analysis of the 5' region-encoded response also suggests that recombinant alpha and gamma interferons may exert their effects on class I gene expression by using different cis-acting regulatory sequences

A genetic validation study reveals a role of vitamin D metabolism in the response to interferon-alfa-based therapy of chronic hepatitis C

Background: To perform a comprehensive study on the relationship between vitamin D metabolism and the response to interferon-α-based therapy of chronic hepatitis C. Methodology/Principal Findings: Associations between a functionally relevant polymorphism in the gene encoding the vitamin D 1α-hydroxylase (CYP27B1-1260 rs10877012) and the response to treatment with pegylated interferon-α (PEG-IFN-α) and ribavirin were determined in 701 patients with chronic hepatitis C. In addition, associations between serum concentrations of 25-hydroxyvitamin D3 (25[OH]D3) and treatment outcome were analysed. CYP27B1-1260 rs10877012 was found to be an independent predictor of sustained virologic response (SVR) in patients with poor-response IL28B genotypes (15% difference in SVR for rs10877012 genotype AA vs. CC, p = 0.02, OR = 1.52, 95% CI = 1.061–2.188), but not in patients with favourable IL28B genotype. Patients with chronic hepatitis C showed a high prevalence of vitamin D insufficiency (25[OH]D3<20 ng/mL) during all seasons, but 25(OH)D3 serum levels were not associated with treatment outcome. Conclusions/Significance: Our study suggests a role of bioactive vitamin D (1,25[OH]2D3, calcitriol) in the response to treatment of chronic hepatitis C. However, serum concentration of the calcitriol precursor 25(OH)D3 is not a suitable predictor of treatment outcome

Multiple tumor suppressors regulate a HIF-dependent negative feedback loop via ISGF3 in human clear cell renal cancer.

Whereas VHL inactivation is a primary event in clear cell renal cell carcinoma (ccRCC), the precise mechanism(s) of how this interacts with the secondary mutations in tumor suppressor genes, including PBRM1, KDM5C/JARID1C, SETD2, and/or BAP1, remains unclear. Gene expression analyses reveal that VHL, PBRM1, or KDM5C share a common regulation of interferon response expression signature. Loss of HIF2α, PBRM1, or KDM5C in VHL-/-cells reduces the expression of interferon stimulated gene factor 3 (ISGF3), a transcription factor that regulates the interferon signature. Moreover, loss of SETD2 or BAP1 also reduces the ISGF3 level. Finally, ISGF3 is strongly tumor-suppressive in a xenograft model as its loss significantly enhances tumor growth. Conversely, reactivation of ISGF3 retards tumor growth by PBRM1-deficient ccRCC cells. Thus after VHL inactivation, HIF induces ISGF3, which is reversed by the loss of secondary tumor suppressors, suggesting that this is a key negative feedback loop in ccRCC. © 2018, Liao et al

Gamma interferon-dependent clearance of cytomegalovirus infection in salivary glands

Cytomegalovirus (CMV), similar to other members of the Herpesviridae family, can establish both persistent and latent infections. Each of the CMVs that are found in many animal species replicates in the salivary gland, and oral secretion represents a source of horizontal transmission. Locally restricted replication characterizes the immunocompetent individual, whereas in the immunocompromised host, protean disease manifestations occur due to virus dissemination. The virus is cleared by immune surveillance, and CD8+ T lymphocytes play a major role. Remarkably, certain cell types of salivary gland tissues are exempt from CD8+ T-lymphocyte control of murine CMV infection and require the activity of CD4+ T lymphocytes. The results presented here suggest that this activity is a function of Th1 cells. Neutralization of endogenous gamma interferon abrogated the antiviral activity of Th1 cells but not that of CD8+ T lymphocytes in other tissues. Neutralization of endogenous gamma interferon did not interfere with the induction of the cellular and humoral immune response but acted during the effector phase. Recombinant gamma interferon could not replace the function of Th1 cells in vivo and had limited direct antiviral activity in vitro. The results therefore suggest that gamma interferon represents one, but not the only, essential factor involved in salivary gland clearance, establishment of CMV latency, and, eventually, the control of horizontal transmission

An unbiased genetic screen reveals the polygenic nature of the influenza virus anti-interferon response.

Influenza A viruses counteract the cellular innate immune response at several steps, including blocking RIG I-dependent activation of interferon (IFN) transcription, interferon (IFN)-dependent upregulation of IFN-stimulated genes (ISGs), and the activity of various ISG products; the multifunctional NS1 protein is responsible for most of these activities. To determine the importance of other viral genes in the interplay between the virus and the host IFN response, we characterized populations and selected mutants of wild-type viruses selected by passage through non-IFN-responsive cells. We reasoned that, by allowing replication to occur in the absence of the selection pressure exerted by IFN, the virus could mutate at positions that would normally be restricted and could thus find new optimal sequence solutions. Deep sequencing of selected virus populations and individual virus mutants indicated that nonsynonymous mutations occurred at many phylogenetically conserved positions in nearly all virus genes. Most individual mutants selected for further characterization induced IFN and ISGs and were unable to counteract the effects of exogenous IFN, yet only one contained a mutation in NS1. The relevance of these mutations for the virus phenotype was verified by reverse genetics. Of note, several virus mutants expressing intact NS1 proteins exhibited alterations in the M1/M2 proteins and accumulated large amounts of deleted genomic RNAs but nonetheless replicated to high titers. This suggests that the overproduction of IFN inducers by these viruses can override NS1-mediated IFN modulation. Altogether, the results suggest that influenza viruses replicating in IFN-competent cells have tuned their complete genomes to evade the cellular innate immune system and that serial replication in non-IFN-responsive cells allows the virus to relax from these constraints and find a new genome consensus within its sequence space. IMPORTANCE In natural virus infections, the production of interferons leads to an antiviral state in cells that effectively limits virus replication. The interferon response places considerable selection pressure on viruses, and they have evolved a variety of ways to evade it. Although the influenza virus NS1 protein is a powerful interferon antagonist, the contributions of other viral genes to interferon evasion have not been well characterized. Here, we examined the effects of alleviating the selection pressure exerted by interferon by serially passaging influenza viruses in cells unable to respond to interferon. Viruses that grew to high titers had mutations at many normally conserved positions in nearly all genes and were not restricted to the NS1 gene. Our results demonstrate that influenza viruses have fine-tuned their entire genomes to evade the interferon response, and by removing interferon-mediated constraints, viruses can mutate at genome positions normally restricted by the interferon response

The effect of abrupt weaning of suckler calves on the plasma concentrations of cortisol, catecholamines, leukocyte, acute-phase proteins and in vitro interferon-gamma production

End of project reportThe objective of this study was to examine the effect of abrupt weaning (inclusive of social group disruption and maternal separation) on the physiological mediators of stress and measures of immune function. Thirty-eight male and 38 female continental calves were habituated to handling for two weeks prior to bleeding. Calves were blocked on sex, weight and breed of dam and randomly assigned, within block, to either a control (cows remain with calves) or abruptly weaned group (calves removed from cows). Animals were separated into the respective treatment groups at weaning (0 h). Calves were bled at – 168 h, 6 h (males only), 24 h, 48 h and 168 h post weaning. At each sampling time an observer scored the behavioural reaction of calves to sampling. Blood samples were analysed for cortisol, catecholamine concentrations (not sampled at –168 h) and in vitro interferon-gamma production, neutrophil :lymphocyte ratio and acute phase protein concentrations. All continuous data were analysed using a split-plot ANOVA, except that collected at 6 h, which was analysed using a single factor ANOVA model. The effects of weaning, calf sex and time and respective interactions were described. Disruption of the established social groups at 0 h, increased (p<0.001) the plasma cortisol concentration and neutrophil: lymphocyte ratio and reduced the leukocyte concentration (p<0.001) and the in vitro interferon-gamma response to the mitogen concanavalin-A (p<0.001) and keyhole limpet haemocyanin (p<0.001) for weaned and control animals, when compared with –168h. Plasma adrenaline and noradrenaline concentrations were not affected by group disruption. There was no effect of weaning or sex on calf behavioural reaction to handling during blood sampling. Plasma cortisol and adrenaline concentrations were not affected by weaning or sex. Plasma noradrenaline concentration was influenced by weaning x sex (p<0.05) and time x sex (p<0.05). The response increased for male calves with weaning and increased with each sampling time post weaning. For heifers the response was not affected by weaning and plasma concentrations decreased at 168 h post weaning. There was no effect of weaning or sex on leukocyte concentration. The neutrophils : lymphocyte ration increased post weaning (p<0.01) and was affected by sex (p<0.05). Weaning decreased (p<0.05) the in vitro interferon-gamma response to the antigen KLH. There was a time x weaning x sex (p<0.05) interaction for fibrinogen concentration but no effect of treatment on haptoglobin concentration. Abrupt weaning increased plasma cortisol and nor-adrenaline concentrations, which was accompanied by attenuation of in vitro interferon gamma production to novel mitogen and antigen complexes up to 7 days post weaning.European Union Structural Funds (EAGGF

Twenty-four vs. forty-eight weeks of re-therapy with interferon alpha 2b and ribavirin in interferon alpha monotherapy relapsers with chronic hepatitis C.

Roughly 50% of patients with chronic hepatitis C, who relapsed after a previous monotherapy with interferon alpha, will respond in a sustained fashion to 24 weeks of re-therapy with the combination of interferon alpha plus ribavirin. Whether prolonging treatment duration to 48 weeks will further increase sustained response rates remains ill defined. In this randomised controlled pilot trial we compared the efficacy and tolerability of a 24 week with that of a 48 week course of combination therapy with interferon alpha and ribavirin in interferon monotherapy relapsers with chronic hepatitis C. Interferon alpha monotherapy relapsers with chronic hepatitis C were randomised to receive interferon alpha 2b (3 x 3 MIU sc weekly) and oral ribavirin (1000/1200 mg po daily) for either 24 weeks or 48 weeks. Virological response was evaluated by HCV RNA PCR at week 10 (initial response), at the end of treatment (end of- treatment response) and at the end of 24 weeks follow-up (sustained response). Only patients with negative HCV RNA at week 10 continued treatment. Adverse events were recorded at regular intervals. Thirty-seven patients were enrolled, 19 (6 females, median age 43) in the 24 week and 18 (5 females, median age 40) in the 48 week treatment arm. Baseline characteristics were similar in both groups. At treatment week 10, 12/19 (63%) in the 24 week group and 14/18 (78%) patients in the 48 week group had lost HCV RNA in serum (p = 0.33). All initial responders remained HCV RNA negative throughout the treatment period. Sustained response rates were 10/19 (53%) in the 24 week group and 13/18 (72%) in the 48 week group (p = 0.31). Three patients discontinued treatment early (two due to moderate adverse events, one due to non-compliance). Dose modifications were necessary in 9 patients, 4 in the 24 week and 5 in the 48 week group for anaemia, neutropenia, nausea and depression, respectively. Prolonging interferon / ribavirin combination therapy in interferon alpha monotherapy relapsers with chronic hepatitis C from 24 to 48 weeks may increase sustained response rates. Larger controlled trials using pegylated interferon alpha and ribavirin in relapsers with chronic hepatitis C seem warranted

Raised serum transaminases during treatment with pegylated interferon for chronic hepatiti C

Introduction : Serum transaminases rose significantly in 7 patients with chronic hepatitis C, genotypes 2 and 3, who were treated with pegylated interferon and ribavirin. Methods : 219 patients with chronic hepatitis C, genotypes 2 and 3, were treated between 2005 and 2011 following the same protocol. For the 7 patients presented in this paper, the initial liver screen revealed chronic hepatitis C infection only. The same liver screen was repeated following the transaminase rise during the treatment period and failed to reveal additional comorbidity. Results : 5 male and 2 female patients with chronic hepatitis C experienced a rise in serum transaminases after commencement on treatment with pegylated interferon and ribavirin. They all achieved rapid and end of treatment virological responses. 3 of the patients achieved sustained virological response and 4 relapsed. There was no evidence to suggest that steatosis, development of autoimmunity or intercurrent illness was the cause of the liver injury. In 3 out of 7 patients, the level of transaminases exhibited a downward trend after pegylated interferon was changed to non pegylated interferon. Additionally, it is evident that in those patients whose treatment was temporarily or permanently aborted, the rise in transaminases rapidly improved and returned to baseline. Conclusion : Our experience suggests the possibility of a toxic reaction to polyethylene glycol in a small number of patients being treated with pegylated interferon, resulting in an acute hepatitic response which resolved when therapy was stopped or switched to non-pegylated interferon

Prediction of the response of chronic hepatitis C to interferon alfa: a statistical analysis of pretreatment variables

Pretreatment variables that could predict the response of chronic hepatitis C to interferon alfa treatment have not been fully assessed. Eighteen baseline variables were evaluated in a series of 100 consecutive patients treated with a 12 month course of interferon alfa. For the purposes of this study, response was defined as the return to normal of aminotransferase activities before the third month of treatment. Seventy per cent of the patients responded to treatment. Six variables were associated with an increased likelihood of response assessed by univariate analysis. With stepwise multiple regression analysis assessment, however, only three variables remained independently predictive of response: low gamma glutamyltransferase (gamma GT) activities (p 0.66 mu kat/l (n = 45) (p = 0.048). Response was attained in 75% of non-obese patients (n = 80), compared with only 50% of obese patients (n = 20) (p = 0.03). Finally, 80% of patients without cirrhosis (n = 76) responded, while among those with cirrhosis (n = 24) the response rate was only 37% (p 40 years old, and with gamma GT activities >0.66 mu kat/l responded to interferon alfa (p<0.001). Those findings may be useful when evaluating interferon alfa trials and it is suggested that this treatment should be applied early in the course of chronic hepatitis C