The neglected role of type I interferon in the T-cell response: implications for its clinical use

A Case Report of Ropeginterferon Alfa-2b for Polycythemia Vera during Pregnancy

Myeloproliferative neoplasms (MPN) such as essential thrombocythemia (ET) and polycythemia vera (PV) are rare during pregnancy. However, they are harmful because they are associated with an increased risk of thromboembolic, hemorrhagic, or microcirculatory disturbances or placental dysfunction leading to fetal growth restriction or loss. Low-dose aspirin and low-molecular-weight heparin (LMWH) are recommended to reduce pregnancy complications, and interferon (IFN) is the only treatment option for cytoreductive therapy based on the likelihood of live birth in pregnant women with MPN. Since ropeginterferon alfa-2b is the only available IFN in South Korea, we present a case report of ropeginterferon alfa-2b use during pregnancy in an MPN patient. A 40-year-old woman who had been diagnosed with low-risk PV in 2017 and had been maintained on phlebotomy, hydroxyurea (HU), and anagrelide (ANA) for 4 years was confirmed as 5 weeks pregnant on 9 December 2021. After stopping treatment with HU and ANA, the patient showed a rapid increase in platelet count (1113 × 109/L to 2074 × 109/L, normal range, 150–450 × 109/L) and white blood cell count (21.93 × 109/L to 35.55 × 109/L, normal range, 4.0–10.0 × 109/L). Considering the high risk of complications, aggressive cytoreductive treatment was required, for which we chose ropeginterferon alfa-2b, as it is the only available IFN agent in South Korea. The patient underwent 8 cycles of ropeginterferon alfa-2b over 6 months during pregnancy and delivered without any neonatal or maternal complications. This case report highlights the importance of considering treatment options for MPN patients who are pregnant or planning a pregnancy, as well as the need for further investigation into the safety and efficacy of ropeginterferon alfa-2b in this population.

Immunomodulatory antitumor effect of interferon‑beta combined with gemcitabine in pancreatic cancer

Resistance to gemcitabine is common and critically limits its therapeutic efficacy in patients with pancreatic cancer. Interferon‑beta (IFN‑β) induces numerous antitumor effects and synergizes with gemcitabine treatment. The immunomodulatory effects of this treatment regimen have not yet been described. In the present study, the antitumor effect of IFN‑β combined with gemcitabine was investigated in immune competent mice. Mouse KPC3 cells were used in all experiments. Treatment effects were determined with cell proliferation assay. Reverse transcription‑quantitative PCR was used to measure gene expression. For in vivo experiments, cells were subcutaneously injected in immune competent mice. For immune profiling, NanoString analysis was performed on tumor samples of treated and untreated mice. Baseline expression of Ifnar‑1 and Ifnar‑2c in KPC3 cells was 1.42±0.16 and 1.50±0.17, respectively. IC50 value of IFN‑β on cell growth was high (>1,000 IU/ml). IFN‑β pre‑treatment increased the in vitro response to gemcitabine (1.3‑fold decrease in EC50; P<0.001). In vivo, tumor size was not statistically significant smaller in mice treated with IFN‑β plus gemcitabine (707±92 mm3 vs. 1,239±338 mm3 in vehicle‑treated mice; P=0.16). IFN‑β alone upregulated expression of numerous immune‑related genes. This effect was less pronounced when combined with gemcitabine. For the first time, to the best of our knowledge, the immunomodulatory effects of IFN‑β, alone and combined with gemcitabine, in pancreatic cancer were reported. Prognostic markers for predicting effective responses to IFN‑β therapy are urgently needed.

Virus specific tolerance enhanced efficacy of cancer immuno-virotherapy

BACKGROUND

Activation of the immune system to fight cancer is a major goal in immunology and oncology. Although cancer treatment using oncolytic viruses shows promising results, virus mediated oncolysis induces a weak anti-tumor immune response. Upon application of viruses, immune responses against the virus play a significant role in limiting tumor virotherapy. Although suppression of host immunity increases the efficacy of virotherapy against the tumor, but inhibits anti-tumor immune responses. Induction of viral specific tolerance before viral replication may cause the virus to efficiently replicate in tumor cells without affecting the immune responses against tumor antigens. Investigation of the combined strategy of virotherapy and immunotherapy using irradiated tumor cells along with IL-2 and interferon-alpha in virus specific tolerant mice was the goal of this study.

MATERIALS AND METHODS

For tolerance induction, the newborn mice were injected with vesicular stomatitis virus (VSV) subcutaneously. After injection of TC-1 tumor cells to adult tolerant mice and formation of a tumor, irradiated TC-1 cells along with IL-2 and Interferon-alpha expression plasmid were injected twice in mice and followed by virotherapy. Size of tumors and CTL activity against the virus and tumor cells were measured.

RESULT

The results showed increased efficacy of virotherapy in combination with immune-stimulators and tumor cells injection in tolerant mice compared to normal mice.

CONCLUSION

Specific tolerance against the oncolytic virus enhances the efficacy of virotherapy both in monotherapy and in combination with immunotherapy.

Comparison of the Treatment Results for Behçet Uveitis in Patients Treated with Infliximab and Interferon

Purpose: To compare the efficacy and safety of infliximab and interferon in patients with refractory Behçet uveitis.Methods: Medical records of 20 patients treated with infliximab (IFX) and 33 patients treated with interferon (IFN) were retrospectively analyzed by evaluating the number of uveitis attacks, visual acuity and ocular inflammation at 6 and 12 months after initiation of treatment.Results: Mean duration of treatment was 22 ± 18 months in IFX group and 30.3 ± 22.5 months in IFN group. Sixteen patients of IFX group (80%) and 28 patients of IFN group (85%) achieved remission. In both groups, the mean best-corrected visual acuity and all inflammatory parameters improved. In terms of these parameters, there was no significant difference between the two groups.Conclusion: Infliximab and interferon improve control of ocular inflammation and efficiently decrease the relapse rate. Our results determined no significant difference between two agents in controlling intraocular inflammation.

Transcriptome Analysis Shows That IFN-I Treatment and Concurrent SAV3 Infection Enriches MHC-I Antigen Processing and Presentation Pathways in Atlantic Salmon-Derived Macrophage/Dendritic Cells

Type I interferons (IFNs) have been shown to play an important role in shaping adaptive immune responses in addition to their antiviral properties in immune cells. To gain insight into the impact of IFN-I-induced pathways involved in early adaptive immune responses, i.e., antigen-presenting pathways, in an Atlantic salmon-derived (Salmo salar L.) macrophage cell line (TO-cells), we used a comparative de novo transcriptome analysis where cells were treated with IFN-I or kept untreated and concurrently infected with salmonid alphavirus subtype 3 (SAV3). We found that concurrent treatment of TO-cells with IFN-I and SAV3 infection (SAV3/IFN⁺) significantly enriched the major histocompatibility complex class I (MHC-I) pathway unlike the non-IFN-I treated TO-cells (SAV3/IFN⁻) that had lower expression levels of MHC-I pathway-related genes. Genes such as the proteasomal activator (PA28) and β-2 microglobulin (β2M) were only differentially expressed in the SAV3/IFN⁺ cells and not in the SAV3/IFN⁻ cells. MHC-I pathway genes like heat shock protein 90 (Hsp90), transporter of antigen associated proteins (TAPs) and tapasin had higher expression levels in the SAV3/IFN⁺ cells than in the SAV3/IFN⁻ cells. There were no MHC-II pathway-related genes upregulated in SAV3/IFN⁺-treated cells, and cathepsin S linked to the degradation of endosomal antigens in the MHC-II pathway was downregulated in the SAV3/IFN⁻ cells. Overall, our findings show that concurrent IFN-I treatment of TO-cells and SAV3 infection enriched gene expression linked to the MHC-I antigen presentation pathway. Data presented indicate a role of type I IFNs in strengthening antigen processing and presentation that may facilitate activation particularly of CD8+ T-cell responses following SAV3 infection, while SAV3 infection alone downplayed MHC-II pathways.

Delivering Type I Interferon to Dendritic Cells Empowers Tumor Eradication and Immune Combination Treatments

An ideal generic cancer immunotherapy should mobilize the immune system to destroy tumor cells without harming healthy cells and remain active in case of recurrence. Furthermore, it should preferably not rely on tumor-specific surface markers, as these are only available in a limited set of malignancies. Despite approval for treatment of various cancers, clinical application of cytokines is still impeded by their multiple toxic side effects. Type I IFN has a long history in the treatment of cancer, but its multifaceted activity pattern and complex side effects prevent its clinical use. Here we develop AcTakines (Activity-on-Target cytokines), optimized (mutated) immunocytokines that are up to 1,000-fold more potent on target cells, allowing specific signaling in selected cell types only. Type I IFN-derived AcTaferon (AFN)-targeting Clec9A⁺ dendritic cells (DC) displayed strong antitumor activity in murine melanoma, breast carcinoma, and lymphoma models and against human lymphoma in humanized mice without any detectable toxic side effects. Combined with immune checkpoint blockade, chemotherapy, or low-dose TNF, complete tumor regression and long-lasting tumor immunity were observed, still without adverse effects. Our findings indicate that DC-targeted AFNs provide a novel class of highly efficient, safe, and broad-spectrum off-the-shelf cancer immunotherapeutics with no need for a tumor marker.Significance: Targeted type I interferon elicits powerful antitumor efficacy, similar to wild-type IFN, but without any toxic side effects. Cancer Res; 78(2); 463-74. ©2017 AACR.

A safe and highly efficient tumor-targeted type I interferon immunotherapy depends on the tumor microenvironment

Despite approval for the treatment of various malignancies, clinical application of cytokines such as type I interferon (IFN) is severely impeded by their systemic toxicity. AcTakines (Activity-on-Target cytokines) are optimized immunocytokines that, when injected in mice, only reveal their activity upon cell-specific impact. We here show that type I IFN-derived AcTaferon targeted to the tumor displays strong antitumor activity without any associated toxicity, in contrast with wild type IFN. Treatment with CD20-targeted AcTaferon of CD20⁺ lymphoma tumors or melanoma tumors engineered to be CD20⁺, drastically reduced tumor growth. This antitumor effect was completely lost in IFNAR- or Batf3-deficient mice, and depended on IFN signaling in conventional dendritic cells. Also the presence of, but not the IFN signaling in, CD8⁺ T lymphocytes was critical for proficient antitumor effects. When combined with immunogenic chemotherapy, low-dose TNF, or immune checkpoint blockade strategies such as anti-PDL1, anti-CTLA4 or anti-LAG3, complete tumor regressions and subsequent immunity (memory) were observed, still without any concomitant morbidity, again in sharp contrast with wild type IFN. Interestingly, the combination therapy of tumor-targeted AcTaferon with checkpoint inhibiting antibodies indicated its ability to convert nonresponding tumors into responders. Collectively, our findings demonstrate that AcTaferon targeted to tumor-specific surface markers may provide a safe and generic addition to cancer (immuno)therapies.

Interferon alpha inhibits replication of a live-attenuated porcine reproductive and respiratory syndrome virus vaccine preventing development of an adaptive immune response in swine

Type I interferons, such as interferon alpha (IFN-α), contribute to innate antiviral immunity by promoting production of antiviral mediators and are also involved in promoting an adaptive immune response. Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most devastating and costly viruses to the swine industry world-wide and has been shown to induce a meager IFN-α response. Previously we administered porcine IFN-α using a replication-defective adenovirus vector (Ad5-IFN-α) at the time of challenge with virulent PRRSV and demonstrated an increase in the number of virus-specific IFNγ secreting cells, indicating that the presence of IFN-α at the time of infection can alter the adaptive immune responses to PRRSV. In the current experiment, we explored the use of IFN-α as an adjuvant administered with live-attenuated PRRSV vaccine as a method to enhance immune response to the vaccine. Unlike the previous studies with fully virulent virus, one injection of the Ad5-IFN-α abolished replication of the vaccine virus and as a result there was no detectible adaptive immune response. Although IFN-α did not have the desired adjuvant effect, the results further highlight the use of IFN-α as a treatment for PRRSV infection.

The added value of type I interferons to cytotoxic treatments of cancer

Type I interferons (IFNs) exert anti-proliferative, antiviral and immunomodulatory activities. They are also involved in cell differentiation and anti-tumor defense processes. A growing body of literature indicates that the success of conventional chemotherapeutics, epigenetic drugs, targeted anticancer agents and radiotherapy (RT) relies, at least in part, on the induction of type I IFN signaling in malignant cells, tumor-infiltrating antigen presenting cells or other immune cells within lymphoid organs or blood. The mechanisms underlying type I IFN induction and the clinical consequences of these observations are only beginning to be elucidated. In the present manuscript, we reviewed the recent advances in the field and provided our personal view on the role of type I IFNs induced in the context of cytotoxic anticancer treatments and on its possible exploitation as a complement in cancer therapy.

High Serum Lipopolysaccharide-Binding Protein Level in Chronic Hepatitis C Viral Infection Is Reduced by Anti-Viral Treatments

Background

Lipopolysaccharide-binding protein (LBP) has been reported to associate with metabolic diseases, such as obesity, diabetes, and non-alcoholic fatty liver disease. Since chronic hepatitis C virus (HCV) infection is associated with metabolic derangements, the relationship between LBP and HCV deserves additional studies. This study aimed to determine the serum LBP level in subjects with or without HCV infection and investigate the change of its level after anti-viral treatments with or without interferon.

Methods and Findings

We recruited 120 non-HCV subjects, 42 and 17 HCV-infected subjects respectively treated with peginterferon α-2a/ribavirin and direct-acting antiviral drugs. Basic information, clinical data, serum LBP level and abdominal ultrasonography were collected. All the subjects provided written informed consent before being enrolled approved by the Research Ethics Committee of the National Taiwan University Hospital. Serum LBP level was significantly higher in HCV-infected subjects than non-HCV subjects (31.0 ± 8.8 versus 20.0 ± 6.4 μg/mL; p-value < 0.001). After multivariate analyses, LBP at baseline was independently associated with body mass index, hemoglobin A1c, alanine aminotransferase (ALT) and HCV infection. Moreover, the baseline LBP was only significantly positively associated with ALT and inversely with fatty liver in HCV-infected subjects. The LBP level significantly decreased at sustained virologic response (27.4 ± 6.6 versus 34.6 ± 7.3 μg/mL, p-value < 0.001; 15.9 ± 4.4 versus 22.2 ± 5.7 μg/mL, p-value = 0.001), regardless of interferon-based or -free therapy.

Conclusions

LBP, an endotoxemia associated protein might be used as an inflammatory biomarker of both infectious and non-infectious origins in HCV-infected subjects.

Review: The role of the liver in the response to LPS: experimental and clinical findings

The liver plays an important physiological role in lipopolysaccharide (LPS) detoxification and, in particular, hepatocytes are involved in the clearance of endotoxin of intestinal derivation. In experimental shock models, tumor necrosis factor (TNF)-α induces hepatocyte apoptosis and lethal effects are due to secreted TNF-α and not to cell-associated TNF-α. An exaggerated production of TNF-α has been reported in murine viral infections, in which mice become sensitized to low amounts of LPS and both interferon (IFN)-γ and IFN-α/β are involved in the macrophage-induced release of TNF-α. The prominent role of LPS and TNF-α in liver injury is also supported by studies of ethanol-induced hepatic damage. In humans, evidence of LPS-induced hepatic injury has been reported in cirrhosis, autoimmune hepatitis, and primary biliary cirrhosis and a decreased phagocytic activity of the reticulo-endothelial system has been found in these diseases. The origin of endotoxemia in hepatitis C virus (HCV) infected patients seems to be multifactorial and LPS may be of exogenous or endogenous derivation. In endotoxemic HCV-positive patients responsive to a combined treatment with IFN-α/ribavirin (RIB), endotoxemia was no longer detected at the end of the therapeutic regimen. By contrast, 48% of the non-responders to this treatment were still endotoxemic and their monocytes displayed higher intracellular TNF-α and interleukin (IL)-1β levels than responders. Moreover, in responders, an equilibrium between IFN-γ and IL-10 serum levels was attained. In the non-responders, serum levels of IL-10 did not increase following treatment. This may imply that an imbalance between T helper (Th)1 and Th2 derived cytokines could be envisaged in the non-responders.

Targeted immunotherapy using anti-CD138-interferon α fusion proteins and bortezomib results in synergistic protection against multiple myeloma

Although recent advances have substantially improved the management of multiple myeloma, it remains an incurable malignancy. We now demonstrate that anti-CD138 molecules genetically fused to type I interferons (IFN) synergize with the approved therapeutic bortezomib in arresting the proliferation of human multiple myeloma cell lines both in vitro and in vivo. The anti-CD138-IFNα14 fusion protein was active in inducing increased expression of signal transducer and activator of transcription 1 (STAT1) and its phosphorylation while the cell death pathway induced by bortezomib included generation of reactive oxygen species. Interferon regulatory factor 4 (IRF4), an important survival factor for myeloma cells, was down regulated following combination treatment. Induction of cell death appeared to be caspase-independent because treatment with inhibitors of caspase activation did not decrease the level of cell death. The observed caspase-independent synergistic cell death involved mitochondrial membrane depolarization, and poly(ADP-ribose) polymerase-1 (PARP-1) cleavage, and resulted in enhanced induction of apoptosis. Importantly, using 2 different in vivo xenograft models, we found that combination therapy of anti-CD138-IFNα14 and bortezomib was able to cure animals with established tumors (7 of 8 using OCI-My5 or 8 of 8 using NCI-H929). Thus, the combination of anti-CD138-IFNα with bortezomib shows great promise as a novel therapeutic approach for the treatment of multiple myeloma, a malignancy for which there are currently no cures.

Age-Associated Failure To Adjust Type I IFN Receptor Signaling Thresholds after T Cell Activation

With increasing age, naive CD4 T cells acquire intrinsic defects that compromise their ability to respond and differentiate. Type I IFNs, pervasive constituents of the environment in which adaptive immune responses occur, are known to regulate T cell differentiation and survival. Activated naive CD4 T cells from older individuals have reduced responses to type I IFN, a defect that develops during activation and that is not observed in quiescent naive CD4 T cells. Naive CD4 T cells from young adults upregulate the expression of STAT1 and STAT5 after activation, lowering their threshold to respond to type I IFN stimulation. The heightened STAT signaling is critical to maintain the expression of CD69 that regulates lymphocyte egress and the ability to produce IL-2 and to survive. Although activation of T cells from older adults also induces transcription of STAT1 and STAT5, failure to exclude SHP-1 from the signaling complex blunts their type I IFN response. In summary, our data show that type I IFN signaling thresholds in naive CD4 T cells after activation are dynamically regulated to respond to environmental cues for clonal expansion and memory cell differentiation. Naive CD4 T cells from older adults have a defect in this threshold calibration. Restoring their ability to respond to type I IFN emerges as a promising target to restore T cell responses and to improve the induction of T cell memory.

Proteomic-based approach to gain insight into reprogramming of THP-1 cells exposed to Leishmania donovani over an early temporal window

Leishmania donovani, a protozoan parasite, is the causative agent of visceral leishmaniasis. It lives and multiplies within the harsh environment of macrophages. In order to investigate how intracellular parasite manipulate the host cell environment, we undertook a quantitative proteomic study of human monocyte-derived macrophages (THP-1) following infection with L. donovani. We used the isobaric tags for relative and absolute quantification (iTRAQ) method and liquid chromatography-tandem mass spectrometry (LC-MS/MS) to compare expression profiles of noninfected and L. donovani-infected THP-1 cells. We detected modifications of protein expression in key metabolic pathways, including glycolysis and fatty acid oxidation, suggesting a global reprogramming of cell metabolism by the parasite. An increased abundance of proteins involved in gene transcription, RNA splicing (heterogeneous nuclear ribonucleoproteins [hnRNPs]), histones, and DNA repair and replication was observed at 24 h postinfection. Proteins involved in cell survival and signal transduction were more abundant at 24 h postinfection. Several of the differentially expressed proteins had not been previously implicated in response to the parasite, while the others support the previously identified proteins. Selected proteomics results were validated by real-time PCR and immunoblot analyses. Similar changes were observed in L. donovani-infected human monocyte-derived primary macrophages. The effect of RNA interference (RNAi)-mediated gene knockdown of proteins validated the relevance of the host quantitative proteomic screen. Our findings indicate that the host cell proteome is modulated after L. donovani infection, provide evidence for global reprogramming of cell metabolism, and demonstrate the complex relations between the host and parasite at the molecular level.

Unraveling the Specific Ischemic Core and Penumbra Transcriptome in the Permanent Middle Cerebral Artery Occlusion Mouse Model Brain Treated with the Neuropeptide PACAP38

Our group has been systematically investigating the effects of the neuropeptide pituitary adenylate-cyclase activating polypeptide (PACAP) on the ischemic brain. To do so, we have established and utilized the permanent middle cerebral artery occlusion (PMCAO) mouse model, in which PACAP38 (1 pmol) injection is given intracerebroventrically and compared to a control saline (0.9% sodium chloride, NaCl) injection, to unravel genome‑wide gene expression changes using a high-throughput DNA microarray analysis approach. In our previous studies, we have accumulated a large volume of data (gene inventory) from the whole brain (ipsilateral and contralateral hemispheres) after both PMCAO and post-PACAP38 injection. In our latest research, we have targeted specifically infarct or ischemic core (hereafter abbreviated IC) and penumbra (hereafter abbreviated P) post-PACAP38 injections in order to re-examine the transcriptome at 6 and 24 h post injection. The current study aims to delineate the specificity of expression and localization of differentially expressed molecular factors influenced by PACAP38 in the IC and P regions. Utilizing the mouse 4 × 44 K whole genome DNA chip we show numerous changes (≧/≦ 1.5/0.75-fold) at both 6 h (654 and 456, and 522 and 449 up- and down-regulated genes for IC and P, respectively) and 24 h (2568 and 2684, and 1947 and 1592 up- and down-regulated genes for IC and P, respectively) after PACAP38 treatment. Among the gene inventories obtained here, two genes, brain-derived neurotrophic factor (Bdnf) and transthyretin (Ttr) were found to be induced by PACAP38 treatment, which we had not been able to identify previously using the whole hemisphere transcriptome analysis. Using bioinformatics analysis by pathway- or specific-disease-state focused gene classifications and Ingenuity Pathway Analysis (IPA) the differentially expressed genes are functionally classified and discussed. Among these, we specifically discuss some novel and previously identified genes, such as alpha hemoglobin stabilizing protein (Ahsp), cathelicidin antimicrobial peptide (Camp), chemokines, interferon beta 1 (Ifnb1), and interleukin 6 (Il6) in context of PACAP38-mediated neuroprotection in the ischemic brain. Taken together, the DNA microarray analysis provides not only a great resource for further study, but also reinforces the importance of region-specific analyses in genome-wide identification of target molecular factors that might play a role in the neuroprotective function of PACAP38.

Role of type I interferon in inducing a protective immune response: perspectives for clinical applications

Type I IFNs (IFN-I) are antiviral cytokines endowed with many biological effects, including antitumor activity. Over the last 15 years, an ensemble of studies has revealed that these cytokines play a crucial role in the induction of a protective antitumor immune response. Early in vivo studies in mouse models have been instrumental for understanding the IFN-I-induced host-mediated mechanisms. IFN-α is currently recognized as a powerful inducer of the differentiation/activation of dendritic cells (DCs) and today IFN-α-conditioned DCs represent promising DC candidates for the development of therapeutic cancer vaccines. Moreover, data from pilot clinical trials support the concept of using IFN-α as an enhancer of the response of patients to cancer vaccines. Notably, endogenous IFN-I production does also play a critical role in the antitumor response to some chemotherapeutic agents. Thus, we can now envisage new strategies of clinical use of IFN-α, based on the injection of IFN-conditioned cells as well as the usage of these cytokines as cancer vaccine adjuvants, alone or in combination with other treatments (including epigenetic drugs) to induce an immunogenic cell death and a long lasting antitumor response.

Gene therapy for malignant glioma

Glioblastoma multiforme (GBM) is the most frequent and devastating primary brain tumor in adults. Despite current treatment modalities, such as surgical resection followed by chemotherapy and radiotherapy, only modest improvements in median survival have been achieved. Frequent recurrence and invasiveness of GBM are likely due to the resistance of glioma stem cells to conventional treatments; therefore, novel alternative treatment strategies are desperately needed. Recent advancements in molecular biology and gene technology have provided attractive novel treatment possibilities for patients with GBM. Gene therapy is defined as a technology that aims to modify the genetic complement of cells to obtain therapeutic benefit. To date, gene therapy for the treatment of GBM has demonstrated anti-tumor efficacy in pre-clinical studies and promising safety profiles in clinical studies. However, while this approach is obviously promising, concerns still exist regarding issues associated with transduction efficiency, viral delivery, the pathologic response of the brain, and treatment efficacy. Tumor development and progression involve alterations in a wide spectrum of genes, therefore a variety of gene therapy approaches for GBM have been proposed. Improved viral vectors are being evaluated, and the potential use of gene therapy alone or in synergy with other treatments against GBM are being studied. In this review, we will discuss the most commonly studied gene therapy approaches for the treatment of GBM in preclinical and clinical studies including: prodrug/suicide gene therapy; oncolytic gene therapy; cytokine mediated gene therapy; and tumor suppressor gene therapy. In addition, we review the principles and mechanisms of current gene therapy strategies as well as advantages and disadvantages of each.

Type I interferons as regulators of human antigen presenting cell functions

Type I interferons (IFNs) are pleiotropic cytokines, initially described for their antiviral activity. These cytokines exhibit a long record of clinical use in patients with some types of cancer, viral infections and chronic inflammatory diseases. It is now well established that IFN action mostly relies on their ability to modulate host innate and adaptive immune responses. Work in recent years has begun to elucidate the mechanisms by which type I IFNs modify the immune response, and this is now recognized to be due to effects on multiple cell types, including monocytes, dendritic cells (DCs), NK cells, T and B lymphocytes. An ensemble of results from both animal models and in vitro studies emphasized the key role of type I IFNs in the development and function of DCs, suggesting the existence of a natural alliance between these cytokines and DCs in linking innate to adaptive immunity. The identification of IFN signatures in DCs and their dysregulation under pathological conditions will therefore be pivotal to decipher the complexity of this DC-IFN interaction and to better exploit the therapeutic potential of these cells.

Type I interferon signals in macrophages and dendritic cells control dengue virus infection: implications for a new mouse model to test dengue vaccines

Dengue virus (DENV) infects an estimated 400 million people every year, causing prolonged morbidity and sometimes mortality. Development of an effective vaccine has been hampered by the lack of appropriate small animal models; mice are naturally not susceptible to DENV and only become infected if highly immunocompromised. Mouse models lacking both type I and type II interferon (IFN) receptors (AG129 mice) or the type I IFN receptor (IFNAR(-/-) mice) are susceptible to infection with mouse-adapted DENV strains but are severely impaired in mounting functional immune responses to the virus and thus are of limited use for study. Here we used conditional deletion of the type I IFN receptor (IFNAR) on individual immune cell subtypes to generate a minimally manipulated mouse model that is susceptible to DENV while retaining global immune competence. Mice lacking IFNAR expression on CD11c(+) dendritic cells and LysM(+) macrophages succumbed completely to DENV infection, while mice deficient in the receptor on either CD11c(+) or LysM(+) cells were susceptible to infection but often resolved viremia and recovered fully from infection. Conditional IFNAR mice responded with a swift and strong CD8(+) T-cell response to viral infection, compared to a weak response in IFNAR(-/-) mice. Furthermore, mice lacking IFNAR on either CD11c(+) or LysM(+) cells were also sufficiently immunocompetent to raise a protective immune response to a candidate subunit vaccine against DENV-2. These data demonstrate that mice with conditional deficiencies in expression of the IFNAR represent improved models for the study of DENV immunology and screening of vaccine candidates.

IMPORTANCE

Dengue virus infects 400 million people every year worldwide, causing 100 million clinically apparent infections, which can be fatal if untreated. Despite many years of research, there are no effective vaccine and no antiviral treatment available for dengue. Development of vaccines has been hampered in particular by the lack of a suitable small animal model. Mouse models used to test dengue vaccine are deficient in interferon (IFN) type I signaling and severely immunocompromised and therefore likely not ideal for the testing of vaccines. In this study, we explored alternative models lacking the IFN receptor only on certain cell types. We show that mice lacking the IFN receptor on either CD11c- or LysM-expressing cells (conditional IFNAR mice) are susceptible to dengue virus infection. Importantly, we demonstrate that conditional IFN receptor knockout mice generate a better immune response to live virus and a candidate dengue vaccine compared to IFNAR mice and are resistant to subsequent challenge.

Rapamycin has suppressive and stimulatory effects on human plasmacytoid dendritic cell functions

Plasmacytoid dendritic cells (PDC) are involved in innate immunity by interferon (IFN)-α production, and in adaptive immunity by stimulating T cells and inducing generation of regulatory T cells (Treg ). In this study we studied the effects of mammalian target of rapamycin (mTOR) inhibition by rapamycin, a commonly used immunosuppressive and anti-cancer drug, on innate and adaptive immune functions of human PDC. A clinically relevant concentration of rapamycin inhibited Toll-like receptor (TLR)-7-induced IFN-α secretion potently (-64%) but TLR-9-induced IFN-α secretion only slightly (-20%), while the same concentration suppressed proinflammatory cytokine production by TLR-7-activated and TLR-9-activated PDC with similar efficacy. Rapamycin inhibited the ability of both TLR-7-activated and TLR-9-activated PDC to stimulate production of IFN-γ and interleukin (IL)-10 by allogeneic T cells. Surprisingly, mTOR-inhibition enhanced the capacity of TLR-7-activated PDC to stimulate naive and memory T helper cell proliferation, which was caused by rapamycin-induced up-regulation of CD80 expression on PDC. Finally, rapamycin treatment of TLR-7-activated PDC enhanced their capacity to induce CD4(+) forkhead box protein 3 (FoxP3)(+) regulatory T cells, but did not affect the generation of suppressive CD8(+) CD38(+) lymphocyte activation gene (LAG)-3(+)  Treg . In general, rapamycin inhibits innate and adaptive immune functions of TLR-stimulated human PDC, but enhances the ability of TLR-7-stimulated PDC to stimulate CD4(+) T cell proliferation and induce CD4(+) FoxP3(+) regulatory T cell generation.

Addition of interferon-α to the p53-SLP® vaccine results in increased production of interferon-γ in vaccinated colorectal cancer patients: a phase I/II clinical trial

We previously established safety and immunogenicity of a p53 synthetic long peptides (p53-SLP®) vaccine. In the current trial, we investigated whether combination of interferon-alpha (IFN-α) with p53-SLP® is both safe and able to improve the induced p53-specific IFN-γ response. Eleven colorectal cancer patients successfully treated for metastatic disease were enrolled in this study. Of these, nine patients completed follow-up after two injections with p53-SLP® together with IFN-α. Safety and p53-specific immune responses were determined before and after vaccination. Furthermore, cryopreserved PBMCs were compared head-to-head to cryopreserved PBMCs obtained in our previous trial with p53-SLP® only. Toxicity of p53-SLP® vaccination in combination with IFN-α was limited to Grade 1 or 2, with predominantly small ongoing swellings at the vaccination site. All patients harbored p53-specific T cells after vaccination and most patients showed p53-specific antibodies. Compared to the previous trial, addition of IFN-α significantly improved the frequency of p53-specific T cells in IFN-γ ELISPOT. Moreover, in this trial, p53-specific T cells were detectable in blood samples of all patients in a direct ex vivo multiparameter flowcytometric assay, opposed to only 2 of 10 patients vaccinated with p53-SLP® only. Finally, patients in this trial displayed a broader p53-specific immunoglobulin-G response, indicating an overall better p53-specific T-helper response. Our study shows that p53-SLP® vaccination combined with IFN-α injection is safe and capable of inducing p53-specific immunity. When compared to a similar trial with p53-SLP® vaccination alone the combination was found to induce significantly more IFN-γ producing p53-specific T cells.

Treatment failure in patients with HPV 16-induced vulvar intraepithelial neoplasia: understanding different clinical responses to immunotherapy

Failure of the immune system to launch a strong and effective immune response to high-risk HPV is related to viral persistence and the development of anogenital (pre)malignant lesions such as vulvar intraepithelial neoplasia (VIN). Different forms of immunotherapy, aimed at overcoming the inertia of the immune system, have been developed and met with clinical success. Unfortunately these, in principal successful, therapeutic approaches also fail to induce clinical responses in a substantial number of cases. In this review, the authors summarize the traits of the immune response to HPV in healthy individuals and in patients with HPV-induced neoplasia. The potential mechanisms involved in the escape of HPV-induced lesions from the immune system indicate gaps in our knowledge. Finally, the interaction between the immune system and VIN is discussed with a special focus on the different forms of immunotherapy applied to treat VIN and the potential causes of therapy failure. The authors conclude that there are a number of pre-existing conditions that determine the patients' responsiveness to immunotherapy. An immunotherapeutic strategy in which different aspects of immune failure are attacked by complementary approaches, will improve the clinical response rate.

Interferon-α as antiviral and antitumor vaccine adjuvants: mechanisms of action and response signature

Interferon-α (IFN-α) are cytokines endowed with multiple biologic effects, including activities on cells of the immune system, which are important for inducing protective antiviral and antitumor responses. Studies in mouse models have been instrumental for understanding the immune adjuvant activity of these cytokines and some of their mechanisms of action. In particular, recent studies conducted on both mouse and human models suggest that IFN-α act as effective immune adjuvants for inducing antiviral and antitumor immunity and that the effects of IFN on the differentiation and activation of dendritic cells (DC) play an important role in the induction of protective responses. In spite of the long record of IFN-α clinical use, a few clinical trials have attempted to evaluate the efficacy of these cytokines used as vaccine adjuvants. Recently, studies on the IFN-α signature in cells from patients treated with IFN-α under different modalities and various clinical settings have provided important insights for understanding the in vivo mechanisms of the IFN immune adjuvant activity in humans and may contribute to the identification of molecular markers with a clinical response. These studies further support the interest of evaluating the clinical efficacy of IFN-α when used as a vaccine adjuvant and also suggest that the DC generated in vitro from monocytes in the presence of this cytokine can exhibit a special advantage for the development of effective therapeutic vaccination strategies in cancer patients.

The presence of alpha interferon at the time of infection alters the innate and adaptive immune responses to porcine reproductive and respiratory syndrome virus

Porcine reproductive and respiratory syndrome (PRRS) is one of the most devastating and costly diseases to the swine industry worldwide. Overall, the adaptive immune response to PRRS virus (PRRSV) is weak, which results in delayed elimination of virus from the host and inferior vaccine protection. PRRSV has been shown to induce a meager alpha interferon (IFN-α) response, and we hypothesized that elevated IFN-α levels early in infection would shorten the induction time and increase elements of the adaptive immune response. To test this, we measured both antibody and cell-mediated immunity in pigs after the administration of a nonreplicating human adenovirus type 5 vector expressing porcine IFN-α (Ad5-pIFN-α) at the time of PRRSV infection and compared the results to those for pigs infected with PRRSV alone. Viremia was delayed, and there was a decrease in viral load in the sera of pigs administered the Ad5-pIFN-α. Although seroconversion was slightly delayed in pigs receiving Ad5-pIFN-α, probably due to the early reduction in viral replication, little difference in the overall or neutralizing antibody response was seen. However, there was an increase in the number of virus-specific IFN-γ-secreting cells detected in the pigs receiving Ad5-pIFN-α, as well as an altered cytokine profile in the lung at 14 days postinfection, indicating that the presence of IFN-α at the time of infection can alter innate and adaptive immune responses to PRRSV.

IFN-α as a vaccine adjuvant: recent insights into the mechanisms and perspectives for its clinical use

The IFN-α family are pleiotropic cytokines with the longest record of clinical use. Over the last decade, new biological effects of IFN-α on immune cells, including dendritic cells, have been described, supporting the concept that these cytokines can act as effective vaccine adjuvants. Recently, an important advance in our understanding of the mechanisms of interferon adjuvant activity has been achieved. Some clinical studies have been performed to assess the adjuvant activity in individuals immunized with preventive vaccines, showing variable results depending on interferon/vaccine formulation and vaccinated subjects. In spite of many data in animal models, little information is available on the possible advantage of utilizing IFN-α as an adjuvant for cancer vaccines in humans. Further clinical trials specifically designed to explore vaccine adjuvant activity are needed in order to define the best conditions for using IFN-α or IFN-α-conditioned dendritic cells for the development of therapeutic vaccines.

Interferon-α-conditioned human monocytes combine a Th1-orienting attitude with the induction of autologous Th17 responses: role of IL-23 and IL-12

IFN-α exerts multiple effects leading to immune protection against pathogens and cancer as well to autoimmune reactions by acting on monocytes and dendritic cells. We analyzed the versatility of human monocytes conditioned by IFN-α towards dendritic cell differentiation (IFN-DC) in shaping the autologous T-helper response. Priming of naïve CD4 T cells with autologous IFN-DC in the presence of either SEA or anti-CD3, resulted, in addition to a prominent expansion of CXCR3+ IFN-γ-producing CD4 Th1 cells, in the emergence of two distinct subsets of IL-17-producing CD4 T cells: i) a predominant Th17 population selectively producing IL-17 and expressing CCR6; ii) a minor Th1/Th17 population, producing both IL-17 and IFN-γ. After phagocytosis of apoptotic cells, IFN-DC induced Th17 cell expansion and IL-17 release. Notably, the use of neutralizing antibodies revealed that IL-23 was an essential cytokine in mediating Th17 cell development by IFN-DC. The demonstration of the IFN-DC-induced expansion of both Th1 and Th17 cell populations reveals the intrinsic plasticity of these DC in orienting the immune response and provides a mechanistic link between IFN-α and the onset of autoimmune phenomena, which have been correlated with both IL-17 production and exposure to IFN-α.

[Janus-faced?: Effects and side-effects of interferon therapy in ophthalmology]

Interferon alpha (IFN-α) and interferon beta (IFN-β) are naturally occurring cytokines, which belong to the type I interferons and share the same receptor leading to very similar therapeutic effects. The immunomodulatory effect of type I interferons includes modulation of antibody production, inhibition of lymphocyte proliferation, inhibition of delayed-type hypersensitivity and enhancement of T-cell and NK-cell cytotoxicity. An increasing number of open clinical studies and case reports have demonstrated the efficacy of IFN-α for severe ocular inflammation in patients with Behçet's disease and of interferon-β, which has been used mainly for the treatment of multiple sclerosis.

Recent advances on the immunomodulatory effects of IFN-alpha: implications for cancer immunotherapy and autoimmunity

Interferons alpha (IFNs-alpha) are pleiotropic cytokines belonging to the type I IFN family, originally described for their antiviral activity. These cytokines exhibit a long record of clinical use in patients with some types of cancer and viral diseases. Notably, certain autoimmune disorders have been postulated to be mediated by endogenous IFN-alpha and are often observed in some IFN-treated patients. IFN-alpha can induce multiple biological effects, including induction/promotion of apoptosis and inhibition of cell growth. In addition, these cytokines promote the differentiation and activity of host immune cells. Early studies in mouse tumor models showed the importance of host immune mechanisms in the generation of a long-lasting antitumor response after injection of the animals with either IFN or tumor cells genetically modified for IFN-alpha production. Several studies have shown that IFN-alpha can induce the rapid differentiation of monocytes into highly activated dendritic cells (DCs). Of note, these DCs (IFN-DCs) are particularly effective in taking up complex antigens and inducing T- and B-cell immunity. The ensemble of these results suggests that IFN-DCs can play a role in the generation of antitumor T-cell immunity, pointing out that these cells could be successfully used in strategies of cancer immunotherapy. Likewise, IFN-alpha-DC interactions could also play a role in the pathogenesis of some autoimmune disorders, often associated with IFN-alpha treatment. All this reveals the complexity of the IFN-alpha-DC interactions under normal and pathological conditions and stimulates further studies for identifying optimal modalities in either using these cytokines or controlling their production/action in patients.

Combination strategies for enhancing the efficacy of immunotherapy in cancer patients

A major challenge in cancer immunotherapy is the identification of effective strategies for enhancing its clinical efficacy. One approach is based on adjuvants capable of breaking tolerance against tumor-associated antigens. Interferon-alpha(IFN-alpha), an antiviral cytokine with a long record of clinical use, has recently been shown to act as an effective adjuvant in cancer patients. Notably, a special interest is currently focused on the use of dendritic cells (DC) generated in the presence of IFN-alpha (IFN-DC) for the preparation of anticancer vaccines. An additional approach for enhancing the response to immunotherapy relies on its combination with chemotherapy. In fact, an ensemble of results from both studies in animal models and pilot clinical trials suggest that certain chemotherapeutic agents can act, under defined conditions, as strong adjuvants for enhancing the efficacy of immunotherapy. These results open new opportunities for designing mechanism-based combination therapies involving both chemotherapy and new-generation cancer vaccines, including IFN-DC-based vaccines.

Retrospective characterization of the S open reading frame of HBV isolated from children with membranous nephropathy treated with interferon-alpha2b

BACKGROUND

A causal relationship exists between HBV infection and membranous nephropathy. The association is especially close in Black children in sub-Saharan Africa. Interferon-alpha2b is commonly used to treat this condition, but is effective in only 30-40% of patients. The reason for the poor response is unknown. The objective of this study was to determine if mutations in the surface gene of HBV isolated from Black children with HBV-associated membranous nephropathy before, during and after interferon treatment, have any effect on treatment response and vice versa.

METHODS

HBV DNA was extracted from a responder, a reverter and a non-responder before and after initiation of 16 weeks of interferon-alpha2b treatment. The preS1/preS2/S region was amplified, cloned and sequenced.

RESULTS

The preS2 region was the most variable in the reverter and the non-responder, and the S region was the most variable in the non-responder. Phylogenetic analysis showed that the viral population dynamics between the responder and the reverter/non-responder strains differed as a result of mutations in the surface gene.

CONCLUSIONS

The presence of mutations in the S region of HBV could be used as predictive markers to differentiate interferon-alpha2b responders from non-responders provided that detailed analysis of further genomes confirms our findings.

Ability of orally administered IFN-α4 to inhibit naturally occurring gingival inflammation in dogs

It has been reported that type I interferons (IFN-α/β) play an important role in innate immune responses against viral and bacterial infections. In this study, we used and examined naturally occurred canine periodontal disease to show the therapeutic efficacy of low dose oral administration (LDOA) of canine IFN-α subtype 4 (CaIFN-α4). We administered purified recombinant CaIFN-α4 expressed in a baculovirus system to dogs with or without gingival inflammation. We found that LDOA of CaIFN-α4 reduce periodontopathic bacterial counts. LDOA induced improvement of naturally occurring gingival inflammation, and reduction of the stress marker responses was also observed after LDOA. These results suggest that LDOA of CaIFN-α4 has effectiveness for improvement of naturally occurring gingival inflammation in dogs.

T follicular helper cells during immunity and tolerance

Helper T cells are required for the generation of a potent immune response to foreign antigens. Amongst them, T follicular helper (Tfh) cells are specialized in promoting protective, long-lived antibody responses that arise from germinal centers. Within these structures, the specificity of B cell receptors may change, due to the process of random somatic hypermutation aimed at increasing the overall affinity of the antibody response. The danger of emerging self-reactive specificities is offset by a stringent selection mechanism delegated in great part to Tfh cells. Only those B cells receiving survival signals from Tfh cells can exit the germinal centers to join the long-lived pools of memory B cells and bone marrow-homing plasma cells. Thus, a crucial immune tolerance checkpoint to prevent long-term autoantibody production lies in the ability to tolerize Tfh cells and to control positive and negative selection signals delivered by this subset. This review tackles the known mechanisms that ensure Tfh tolerance, many of them shared by other T helper subsets during thymic development and priming, but others unique to Tfh cells. Amongst the latter are checkpoints at the stages of Tfh differentiation, follicular migration, growth, longevity, and quality control of selection signals. Finally, we also discuss the consequences of a breakdown in Tfh tolerance.

Current trends in the management of ocular symptoms in Adamantiades-Behçet's disease

Adamantiades-Behçet’s disease (ABD) is a multisystemic vasculitic disease. It is most prevalent in the Eastern Mediterranean countries and the Eastern region of Asia. Its effect on the eye can range from mild to debilitating, resulting in total blindness. A necrotizing and obliterative vasculitis affects both arteries and veins of organs. Recurrent attacks of uveitis, oral aphthous ulcers, skin lesions, and genital ulcers are common. Topical and systemic corticosteroids have been the mainstay in the treatment of ocular inflammation for many years; however, due to the several known side effects of corticosteroids and thanks to scientific advances, more novel approaches to ABD treatment have been emerging. Antimetabolites such as methotrexate and azathioprine have been utilized with the latter showing positive results. Chlorambucil has been utilized effectively for ocular manifestations of ABD. Interferon alpha has shown encouraging results in the management of refractory ocular inflammation associated with ABD, either alone or in combination with other immunosuppressive agents. Surgical interventions to deal with complications from ABD can be safely done if adequate control of inflammation is achieved peri-operatively. Early detection and aggressive treatment, when needed, have proven to be essential in the management of this relentlessly explosive disease.

Transgenic models for cytokine-induced neurological disease

Considerable evidence supports the idea that cytokines are important mediators of pathophysiologic processes within the central nervous system (CNS). Numerous studies have documented the increased production of various cytokines in the human CNS in a variety of neurological and neuropsychiatric disorders. Deciphering cytokine actions in the intact CNS has important implications for our understanding of the pathogenesis and treatment of these disorders. One approach to address this problem that has been used widely employs transgenic mice with CNS-targeted production of different cytokines. Transgenic production of cytokines in the CNS of mice allows not only for the investigation of complex cellular responses at a localized level in the intact brain but also more closely recapitulates the expression of these mediators as found in disease states. As discussed in this review, the findings show that these transgenic animals exhibit wide-ranging structural and functional deficits that are linked to the development of distinct neuroinflammatory responses which are relatively specific for each cytokine. These cytokine-induced alterations often recapitulate those found in various human neurological disorders not only underscoring the relevance of these models but also reinforcing the clinicopathogenetic significance of cytokines in diseases of the CNS.

Type I interferon signaling in dendritic cells stimulates the development of lymph-node-resident T follicular helper cells

T follicular helper (Tfh) cells represent a recently defined CD4(+) T cell subset characterized by the expression of the chemokine receptor CXCR5 and an enhanced ability to support B cells to mount antibody responses. Here, we demonstrate that lymph-node-resident CXCR5(+) Tfh cells and gut-homing integrin alpha(4)beta(7)-expressing T helper cells are generated as separate subsets in the gut-draining mesenteric lymph nodes. Type I interferon signaling in dendritic cells and in nonhematopoietic cells selectively stimulates Tfh cell development in response to antigen in conjunction with Toll-like receptor (TLR)3 or TLR4 agonists. Consistent with this, the ability of dendritic cells to produce the cytokine IL-6, required for in vivo Tfh differentiation, and antibody affinity maturation are both reduced in absence of type I interferon signaling. Thus, our results identify type I interferon as a natural adjuvant that selectively supports the generation of lymph node resident Tfh cells.

CD20-targeted tetrameric interferon-alpha, a novel and potent immunocytokine for the therapy of B-cell lymphomas

Interferon-alpha (IFN-alpha) has direct inhibitory effects on some tumors and is a potent stimulator of both the innate and adaptive immune systems. A tumor-targeting antibody-IFN-alpha conjugate (mAb-IFN-alpha) could kill by direct actions of the monoclonal antibody (mAb) and IFN-alpha on tumor cells and also potentiate a tumor-directed immune response. The modular Dock-and-Lock method (DNL) was used to generate 20-2b, the first immunocytokine having 4 cytokine (IFN-alpha2b) groups that are fused to the humanized anti-CD20 mAb, veltuzumab. Additional mAb-IFN-alpha constructs, each retaining potent IFN-alpha2b biologic activity, also were produced by DNL. The 20-2b shows enhanced antibody-dependent cellular cytotoxicity compared with veltuzumab but lacks complement-dependent cytotoxicity. The 20-2b inhibits in vitro proliferation of lymphoma cells and depletes them from whole human blood more potently than the combination of veltuzumab and a nontargeting, irrelevant, mAb-IFN-alpha. The 20-2b demonstrated superior therapeutic efficacy compared with veltuzumab or nontargeting mAb-IFN-alpha in 3 human lymphoma xenograft models, even though mouse immune cells respond poorly to human IFN-alpha2b. Targeting IFN-alpha with an anti-CD20 mAb makes the immunocytokine more potent than either agent alone. These findings suggest that 20-2b merits clinical evaluation as a new candidate antilymphoma therapeutic.

Long-term survival benefit after adjuvant treatment of cutaneous melanoma with dacarbazine and low dose natural interferon alpha: A controlled, randomised multicentre trial

In a prospective, controlled, randomised, multicentre study 252 patients with totally resected cutaneous melanoma (248 in stage II-III and 4 in stage IV) were either treated with two doses of dacarbazine (DTIC) followed by a 6-month treatment with 3 MU thrice weekly of highly purified natural interferon-alpha (n = 128; arm A) or received no adjuvant treatment (n = 124; arm B). Treatment was well tolerated. After a median follow-up of 8.5 years ITT analysis showed that the difference in survival was statistically significant with respect to melanoma-related deaths (HR = 0.65, CI = 0.46-0.97, p = 0.022) and close to significance with respect to overall survival (HR 0.71, CI 0.49-1.00, p = 0.052). The risk reduction of melanoma-associated death, calculated by Cox proportional hazards modelling, after adjusting for identified predictive variables, was almost 50% (p = 0.002). The overall efficacy of the treatment appeared to be mainly attributable to effects observed in patients with deep and/or metastasizing tumours (HR 0.60, CI 0.40-0.90, p = 0.013).

Adenovirus-mediated expression of interferon-alpha delays viral replication and reduces disease signs in swine challenged with porcine reproductive and respiratory syndrome virus

In this study, pigs were injected with a nonreplicating human adenovirus type 5 vector expressing porcine interferon-alpha (Ad5-pIFN-alpha) and then challenged with porcine reproductive and respiratory syndrome virus (PRRSV) to determine whether the presence of increased levels of IFN-alpha would decrease viral replication and/or disease. Groups of 10 pigs each were inoculated with Ad5-pIFN-alpha and not challenged, Ad5-pIFN-alpha and challenged with PRRSV 1 d later, or inoculated with a control adenovirus that does not express IFN-alpha (Ad5-null) and challenged 1 d later with PRRSV. IFN-alpha levels in all pigs inoculated with the Ad5-pIFN-alpha were elevated the day of challenge (1 d after inoculation), but were undetectable by 3 d after inoculation in the pigs that were not challenged with PRRSV. Pigs inoculated with Ad5-pIFN-alpha and challenged with PRRSV had lower febrile responses, a decreased percentage of lung involvement at 10 d post-infection, delayed viremia and antibody response, and higher serum IFN-alpha levels as a result of PRRSV infection, compared to pigs inoculated with Ad5-null and challenged with PRRSV. These results indicate that IFN-alpha can have protective effects if present during the time of infection with PRRSV.

Physiological role of plasmacytoid dendritic cells and their potential use in cancer immunity

Dendritic cells (DCs) play a pivotal role in the control of innate and adaptive immune responses. They are a heterogeneous cell population, where plasmacytoid dendritic cells (pDCs) are a unique subset capable of secreting high levels of type I IFNs. It has been demonstrated that pDCs can coordinate events during the course of viral infection, atopy, autoimmune diseases, and cancer. Therefore, pDC, as a main source of type I IFN, is an attractive target for therapeutic manipulations of the immune system to elicit a powerful immune response against tumor antigens in combination with other therapies. The therapeutic vaccination with antigen-pulsed DCs has shown a limited efficacy to generate an effective long-lasting immune response against tumor cells. A rational manipulation and design of vaccines which could include DC subsets outside “Langerhans cell paradigm” might allow us to improve the therapeutic approaches for cancer patients.

HIV-1 Tat protein induces IL-10 production in monocytes by classical and alternative NF-kappaB pathways

The human immunodeficiency virus (HIV) transactivating Tat protein is not only critical for viral replication but also affects the host immune system by inducing the production of cytokines such as IL-10. This anti-inflammatory cytokine is upregulated during the course of HIV infection, representing an important pathway by which HIV may induce immunodeficiency. Here, we show that, by acting at the membrane, Tat induces IL-10 expression in primary monocytes and promonocytic U937 cells by NF-kappaB-dependent pathways. The trans-dominant negative mutants of NF-kappaB-inducing kinase (NIK), IKKalpha and IKKbeta expressed in our transactivation model, in accordance with the nuclear binding of p65 and p52 NF-kappaB subunits to the IL-10 promoter, suggest the involvement of both classical and alternative NF-kappaB pathways. In inactivated cells, IKKalpha is localized predominantly in the cytoplasm. Interestingly, Tat stimulates IKKalpha translocation from the cytoplasm to the nucleus in monocytes. Chromatin immunoprecipitation (ChIP) assay experiments, after Tat treatment, revealed IKKalpha and CBP/p300 recruitment to the IL-10 promoter and histone H3 phosphorylation (Ser 10) and acetylation (Lys 14) in this region, presumably leading to chromatin remodeling. We demonstrate that, upstream of NF-kappaB, PKC, ERK1/2 and p38 MAP kinases are involved in Tat-induced IKKalpha nuclear translocation and histone H3 modifications on the IL-10 promoter in accordance with the role of these three kinases in IL-10 production. As a whole, the study demonstrates that Tat activates at least three signaling pathways concurrently, including the classical, alternative and IKKalpha pathways, to promote production of IL-10.

IFN-alpha in the generation of dendritic cells for cancer immunotherapy

Dendritic cells (DCs) play a crucial role in linking innate and adaptive immunity, by virtue of their unique ability to take up and process antigens in the peripheral blood and tissues and, upon migration to draining lymph nodes, to present antigen to resting lymphocytes. Notably, these DC functions are modulated by cytokines and chemokines controlling the activation and maturation of these cells, thus shaping the response towards either immunity or tolerance.An ensemble of recent studies have emphasized an important role of type I IFNs in the DC differentiation/activation, suggesting the existence of a natural alliance between these cytokines and DCs in linking innate and adaptive immunity. Herein, we will review how type I IFNs can promote the ex vivo differentiation of human DCs and orient DC functions towards the priming and expansion of protective antitumor immune responses. We will also discuss how the knowledge on type I IFN-DC interactions could be exploited for the design of more selective and effective strategies of cancer immunotherapy.

The role of interleukin-12 in the heavy metal-elicited immunomodulation: relevance of various evaluation methods

Background

Increasing evidence exists that heavy metals modulate T helper cell (Th) responses and thereby elicit various pathological manifestation. Interleukin (IL)-12, a crucial innate cytokine, was found to be regulated by such xenobiotic agents. This study aimed at testing whether IL-12 profiles may be indicative of heavy metals-induced immunomodulation.

Methods

Human immunocompetent cells, activated either by monoclonal antibodies or heat-killed Salmonella enterica, were cultured in the absence or presence of cadmium (Cd) acetate or mercuric (Hg) chloride. In vivo experiments were set up where BALB/c mice were exposed to sub-lethal doses of Cd or Hg salts for 3 or 5 weeks. Cytotoxicity was assessed by MTT-reduction assay. Modulation of cytokine profiles was evaluated by enzyme-linked immunosorbent assay (ELISA), cytometric bead-based array (CBA) and real-time polymerase chain reaction (RT-PCR); the relevance of these methods of cytokine quantification was explored.

Results

Modulation of IL-12 profiles in Cd- or Hg-exposed human PBMC was dose-dependent and significantly related to IFN-γ levels as well as to the Th1- or Th2-polarized responses. Similarly, skewing the Th1/Th2 ratios in vivo correlated significantly with up- or down-regulation of IL-12 levels in both cases of investigated metals.

Conclusion

It can be inferred that: (i) IL-12 profiles alone may represent a relevant indicator of heavy metal-induced immune modulation; (ii) evaluating cytokine profiles by CBA is relevant and can adequately replace other methods such as ELISA and RT-PCR in basic research as well as in immune diagnostics; and (iii) targeting IL-12 in therapeutic approaches may be promising to modify Th1/Th2-associated immune disorders.

Differences in clinical disease and immune response of pigs challenged with a high-dose versus low-dose inoculum of porcine reproductive and respiratory syndrome virus

Porcine reproductive and respiratory syndrome virus (PRRSV) continues to be an economically important infectious disease of swine. Mechanisms governing activation of the innate immune response to PRRSV remain to be elucidated. Virulence differences observed between PRRSV isolates have been attributed to replication ability in vivo, though immunogenic differences likely contribute to virulence also. The current study utilized a single PRRSV isolate given at two different challenge doses to investigate the effect of viral replication and load on immune responses, including type I interferon activation. Body temperature, viral load, antibody levels, cellular infiltration into pulmonary tissue, and the interferon response were measured in animals receiving either a low (10(2) CCID(50)) or high (10(6) CCID(50)) dose of inoculum to understand the role of challenge dose in acute immune responses. Initial PRRSV dose did not correlate with serum levels of PRRSV vRNA or antibody titers during the acute stage of infection (days 2-12 PI), but did have an effect on the immune response and mortality. Type I interferon responses, measured by transcriptional changes in IFN-beta, IFN-alpha, Mx, and PKR, were uniquely different when assessed relative to viral dose or cell type, but no overall trend existed to discern responses based on challenge dose. Serum IFN-gamma levels correlated with serum viral RNA load at day 19 PI. Overall, between days 2 and 12 PI, serum vRNA load was not significantly different between pigs challenged with a low or high dose of PRRSV. Animals receiving high-dose inoculum were viremic longer and eventually succumbed to respiratory disease. IFN-gamma may play a role in PRRSV pathogenesis, as serum levels increased significantly in pigs challenged with the high dose of PRRSV.