Pleiotropic Roles of Type 1 Interferons in Antiviral Immune Responses

Mast cell-derived interleukin-4 mediates activation of dendritic cell during toll-like receptor 2-mediated inflammation

Introduction

During an innate inflammation, immune cells form distinct pro- and anti-inflammatory regions around pathogen-containing core-regions. Mast cells are localized in an anti-inflammatory microenvironment during the resolution of an innate inflammation, suggesting antiinflammatory roles of these cells.

Methods

High-content imaging was used to investigated mast cell-dependent changes in the regional distribution of immune cells during an inflammation, induced by the toll-like receptor (TLR)-2 agonist zymosan.

Results

The distance between the zymosan-containing core-region and the anti-inflammatory region, described by M2-like macrophages, increased in mast cell-deficient mice. Absence of mast cells abolished dendritic cell (DC) activation, as determined by CD86-expression and localized the DCs in greater distance to zymosan particles. The CD86- DCs had a higher expression of the pro-inflammatory interleukins (IL)-1β and IL-12/23p40 as compared to activated CD86+ DCs. IL-4 administration restored CD86 expression, cytokine expression profile and localization of the DCs in mast cell-deficient mice. The IL-4 effects were mast cell-specific, since IL-4 reduction by eosinophil depletion did not affect activation of DCs.

Discussion

We found that mast cells induce DC activation selectively at the site of inflammation and thereby determine their localization within the inflammation. Overall, mast cells have antiinflammatory functions in this inflammation model and limit the size of the pro-inflammatory region surrounding the zymosan-containing core region.

cGLRs Join Their Cousins of Pattern Recognition Receptor Family to Regulate Immune Homeostasis

Pattern recognition receptors (PRRs) recognize danger signals such as PAMPs/MAMPs and DAMPs to initiate a protective immune response. TLRs, NLRs, CLRs, and RLRs are well-characterized PRRs of the host immune system. cGLRs have been recently identified as PRRs. In humans, the cGAS/STING signaling pathway is a part of cGLRs. cGAS recognizes cytosolic dsDNA as a PAMP or DAMP to initiate the STING-dependent immune response comprising type 1 IFN release, NF-κB activation, autophagy, and cellular senescence. The present article discusses the emergence of cGLRs as critical PRRs and how they regulate immune responses. We examined the role of cGAS/STING signaling, a well-studied cGLR system, in the activation of the immune system. The following sections discuss the role of cGAS/STING dysregulation in disease and how immune cross-talk with other PRRs maintains immune homeostasis. This understanding will lead to the design of better vaccines and immunotherapeutics for various diseases, including infections, autoimmunity, and cancers.

A Transcriptional Analysis of Cattle Immune Cells Reveals a Central Role of Type 1 Interferon in the In Vitro Innate Immune Response against Mycobacterium bovis

Bovine tuberculosis is a chronic infectious disease primarily caused by Mycobacterium bovis, a bacterium that affects cattle and other mammals, including humans. Despite the availability of vast research about the immune response mechanisms of human tuberculosis caused by Mycobacterium tuberculosis, the knowledge of bovine tuberculosis's immunology, particularly regarding the innate immune response, still remains scarce. In this study, we compared the transcriptome of cell cultures containing lymphocytes and M. bovis infected-macrophages with two strains of variable virulence, the virulent Mb04-303 strain and the attenuated Mb534. To that end, we infected bovine macrophages at a multiplicity of infection of one, and co-cultured the infections with autologous lymphocytes. RNA obtained from the co-cultures was sequenced to identify differentially expressed gene pathways by using the database Reactome. The RNA-seq analysis showed that the Mb04-303 infection upregulated the type 1 interferon signalling pathway, while it downregulated the KEAP1-NFE2L2 pathway. According to the literature, this last pathway is involved in the activation of antioxidant genes and inflammasome. In addition, the macrophages infected with Mb04-303 recruited more Galectin 8 than those infected with Mb534. This result indicates that Mb04-303 induced higher phagosome membrane damage, with the possible concomitant release of bacterial compounds into the cytoplasm that activates the type I signalling pathway. Altogether, Mb04-303 repressed the antioxidant and anti-inflammatory responses, likely impairing interleukin-1β activation, and trigged the canonical type 1 interferon signalling. Although these responses led to the control of bacterial replication during early infection, the virulent strain eventually managed to establish a successful infection.

Examination of cord blood at birth in women with SARS-CoV-2 exposure and/or vaccination during pregnancy and relationship to fetal complete blood count, cortisol, ferritin, vitamin D, and CRP

Background

SARS-CoV-2 is known to manifest a robust innate immune response. However, little is known about inflammatory influences from maternal SARS-CoV-2 infection or maternal mRNA vaccination upon the fetus. In addition, it is unknown if Vitamin D deficiency influences fetal homeostasis or if an anti-inflammatory mechanism to the development of possible innate cytokines or acute phase reactants by the maternal/fetal dyad, in the form of cortisol elevations, occur. In addition, effects on Complete Blood Count (CBC) are not known.

Objective

To evaluate the neonatal acute phase reactants and anti-inflammatory responses after maternal SARS-CoV-2 disease or mRNA vaccination.

Methods

Samples and medical records reviews from mother/baby dyads (n = 97) were collected consecutively, and were categorized into 4 groups; no SARS-CoV-2 or vaccination exposure (Control), Vaccinated mothers, maternal SARS-CoV-2 disease positive/IgG titer positive fetal blood, and maternal SARS-CoV-2 positive/IgG titer negative fetal blood. SARS-CoV-2 IgG/IgM/IgA titers, CBC, CRP, ferritin, cortisol, and Vitamin D were obtained to examine the possible development of an innate immune response and possible anti-inflammatory response. Student's t-test, Wilcoxon rank-sum, and Chi-squared with Bonferroni corrections were used to compare groups. Multiple imputations were performed for missing data.

Results

Cortisol was higher in babies of both mothers who were vaccinated (p = 0.001) and SARS-CoV-2 positive/IgG positive (p = 0.009) as compared to the control group suggesting an attempt to maintain homeostasis in these groups. Measurements of ferritin, CRP, and vitamin D did not reach statistical significance. CBC showed no variation, except for the mean platelet volume (MPV), which was elevated in babies whose mothers were vaccinated (p = 0.003) and SARS-CoV-2 positive/IgG positive (p = 0.007) as compared to the control group.

Conclusion

Acute phase reactant elevations were not noted in our neonates. Vitamin D levels were unchanged from homeostatic levels. Cord blood at birth, showed Cortisol and MPV higher in vaccinated and SARS-CoV-2 IgG positive mother/baby dyads as compared to the Control group, indicating that possible anti-inflammatory response was generated. The implication of possible inflammatory events and subsequent cortisol and/or MPV elevation effects upon the fetus after SARS-CoV-2 disease or vaccination is unknown and merits further investigation.

Decoupled Glucose and Lipid Metabolic Recovery after Viral Clearance in Direct-Acting Antiviral-Treated HCV Patients: A 3-Year Prospective Cohort Study

BACKGROUND/AIM

The recovery pattern of hepatitis C virus (HCV)-associated metabolic alteration after sustained virological response (SVR) following direct-acting antivirals (DAAs) remains elusive.

METHODS

A prospective cohort study of chronic HCV-infected (CHC) patients (n = 415) receiving DAAs (n = 365) was conducted. Metabolic profiles were examined in SVR patients (n = 360) every 3-6 months after therapy and compared with those of sex- and age-matched controls (n = 470).

RESULTS

At baseline, of 415, 168 (40.5%) had insulin resistance (IR). The following were associated: levels of high-density lipoprotein cholesterol (HDL-C), triglycerides (TGs), HCV RNA, fibrosis-4 score, and interferon-λ3-rs12979860 genotype with total cholesterol (TC) levels; and TG levels and BMI with HOMA-IR. Over a 3-year follow-up, in SVR patients, BMI and TC levels and TG/HDL-C ratios increased from baseline, while HOMA-IR trended downward by 72 weeks after therapy and then increased. The increased HDL-C levels began to decrease after 72 weeks after therapy. TC and HOMA-IR were negatively associated with each other until 24 weeks after therapy. Earlier increases in BMI and decreases in HOMA-IR were noted in SVR patients with than in those without baseline IR. Compared with controls, in the subgroup without baseline IR, SVR patients had increased BMI and HOMA-IR levels. Metabolic profiles were similar between SVR patients and controls in the subgroup with baseline IR.

CONCLUSIONS

In SVR patients treated with DAAs, the recovery of altered lipid and glucose metabolism was not coupled until 72-week post-therapy, when HOMA-IR reached its nadir. SVR patients with baseline IR recovered from HCV-associated metabolic alterations earlier than those without baseline IR.

Critical role of triglycerides for adiponectin levels in hepatitis C: a joint study of human and HCV core transgenic mice

Background

Both hepatitis C virus (HCV) infection and adiponectin are critically involved in metabolism. The reversal and associations of altering adiponectin levels after sustained virological responses (SVRs) following direct-acting antivirals (DAA) in HCV-infected patients remained elusive.

Methods

A joint study was conducted in a prospective cohort of 427 HCV-infected patients and a line of HCV core transgenic mice.

Results

Of 427, 358 had completed a course of DAA therapy and 353 had SVRs. At baseline, male sex (95% CI β: − 1.44 to − 0.417), estimated glomerular filtration rate (eGFR) (− 0.025 to − 0.008), triglycerides (− 0.015 to − 0.005), and fibrosis-4 levels (0.08–0.297) were associated with adiponectin levels; BMI (0.029–0.327) and triglycerides levels (0.01–0.03) were associated with homeostatic model assessment for insulin resistance (HOMA-IR) in HCV-infected patients. At 24-week post-therapy, in SVR patients, male sex (− 1.89 to − 0.5) and eGFR (− 0.02 to − 0.001) levels were associated with adiponectin levels, levels of BMI (0.094–0.335) and alanine transaminase (0.018–0.078) were associated with HOMA-IR; compared with baseline levels, adiponectin levels decreased (6.53 ± 2.77 vs. 5.45 ± 2.56 μg/mL, p < 0.001). In 12-month-old HCV core transgenic mice with hepatic steatosis, triglyceride levels (0.021–0.111) were associated with adiponectin levels, and hepatic adipopnectin expression was comparable with that of control mice.

Conclusions

Triglycerides and hepatic fibrosis are associated with HCV-specific alteration of adiponectin levels, and adiponectin may affect insulin sensitivity through triglycerides during HCV infection. In DAA-treated patients, after SVR, adiponectin levels decreased and the linking function of triglycerides between adiponectin and insulin sensitivity vanished. Moreover, HCV core with hepatic steatosis might affect extrahepatic adiponectin expression through triglycerides.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12865-021-00445-5.

Developing human pluripotent stem cell-based cerebral organoids with a controllable microglia ratio for modeling brain development and pathology

Microglia play critical roles in brain development, homeostasis, and disease. Microglia in animal models cannot accurately model human microglia due to notable transcriptomic and functional differences between human and other animal microglia. Incorporating human pluripotent stem cell (hPSC)-derived microglia into brain organoids provides unprecedented opportunities to study human microglia. However, an optimized method that integrates appropriate amounts of microglia into brain organoids at a proper time point, resembling in vivo brain development, is still lacking. Here, we report a new brain region-specific, microglia-containing organoid model by co-culturing hPSC-derived primitive neural progenitor cells and primitive macrophage progenitors. In the organoids, the number of human microglia can be controlled, and microglia exhibit phagocytic activity and synaptic pruning function. Furthermore, human microglia respond to Zika virus infection of the organoids. Our findings establish a new microglia-containing brain organoid model that will serve to study human microglial function in a variety of neurological disorders.

Dual Effects of Let-7b in the Early Stage of Hepatitis C Virus Infection

MicroRNA let-7b expression is induced by infection of hepatitis C virus (HCV) and is involved in the regulation of HCV replication by directly targeting the HCV genome. The current study demonstrated that let-7b directly targets negative regulators of type I interferon (IFN) signaling thereby limiting HCV replication in the early stage of HCV infection. Let-7b-regulated genes which are involved in host cellular responses to HCV infection were unveiled by microarray profiling and bioinformatic analyses, followed by various molecular and cellular assays using Huh7 cells expressing wild-type (WT) or the seed region-mutated let-7b. Let-7b targeted the cytokine signaling 1 (SOCS1) protein, a negative regulator of JAK/STAT signaling, which then enhanced STAT1-Y701 phosphorylation leading to increased expression of the downstream interferon-stimulated genes (ISGs). Let-7b augmented retinoic acid-inducible gene I (RIG-I) signaling, but not MDA5, to phosphorylate and nuclear translocate IRF3 leading to increased expression of IFN-β. Let-7b directly targeted the ATG12 and IκB kinase alpha (IKKα) transcripts and reduced the interaction of the ATG5-ATG12 conjugate and RIG-I leading to increased expression of IFN, which may further stimulate JAK/STAT signaling. Let-7b induced by HCV infection elicits dual effects on IFN expression and signaling, along with targeting the coding sequences of NS5B and 5' UTR of the HCV genome, and limits HCV RNA accumulation in the early stage of HCV infection. Controlling let-7b expression is thereby crucial in the intervention of HCV infection.IMPORTANCE HCV is a leading cause of liver disease, with an estimated 71 million people infected worldwide. During HCV infection, type I interferon (IFN) signaling displays potent antiviral and immunomodulatory effects. Host factors, including microRNAs (miRNAs), play a role in upregulating IFN signaling to limit HCV replication. Let-7b is a liver-abundant miRNA that is induced by HCV infection and targets the HCV genome to suppress HCV RNA accumulation. In this study, we demonstrated that let-7b, as a positive regulator of type I IFN signaling, plays dual roles against HCV replication by increasing the expression of IFN and interferon-sensitive response element (ISRE)-driven interferon-stimulated genes (ISGs) in the early stage of HCV infection. This study sheds new insight into understanding the role of let-7b in combatting HCV infection. Clarifying IFN signaling regulated by miRNA during the early phase of HCV infection may help researchers understand the initial defense mechanisms to other RNA viruses.

The Abstruse Side of Type I Interferon Immunotherapy for COVID-19 Cases with Comorbidities

The Coronavirus Disease-2019 (COVID-19) pandemic, caused by the novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has claimed 1.2 million people globally since December 2019. Although the host factors underpinning COVID-19 pathology are not fully understood, type I interferon (IFN-I) response is considered crucial for SARS-CoV-2 pathogenesis. Perturbations in IFN-I signaling and associated interferon-inducible genes (ISG) are among the primary disease severity indicators in COVID-19. Consequently, IFN-I therapy, either alone or in- combination with existing antiviral or anti-inflammatory drugs, is tested in many ongoing clinical trials to reduce COVID-19 mortality. Since signaling by the IFN-I family of molecules regulates host immune response to other infectious and non-infectious diseases, any imbalance in this family of cytokines would impact the clinical outcome of COVID-19, as well as other co-existing diseases. Therefore, it is imperative to evaluate the beneficial-versus-detrimental effects of IFN-I immunotherapy for COVID-19 patients with divergent disease severity and other co-existing conditions. This review article summarizes the role of IFN-I signaling in infectious and non-infectious diseases of humans. It highlights the precautionary measures to be considered before administering IFN-I to COVID-19 patients having other co-existing disorders. Finally, suggestions are proposed to improve IFN-I immunotherapy to COVID-19.

Nrf2-interacting nutrients and COVID-19: time for research to develop adaptation strategies

There are large between- and within-country variations in COVID-19 death rates. Some very low death rate settings such as Eastern Asia, Central Europe, the Balkans and Africa have a common feature of eating large quantities of fermented foods whose intake is associated with the activation of the Nrf2 (Nuclear factor (erythroid-derived 2)-like 2) anti-oxidant transcription factor. There are many Nrf2-interacting nutrients (berberine, curcumin, epigallocatechin gallate, genistein, quercetin, resveratrol, sulforaphane) that all act similarly to reduce insulin resistance, endothelial damage, lung injury and cytokine storm. They also act on the same mechanisms (mTOR: Mammalian target of rapamycin, PPARγ:Peroxisome proliferator-activated receptor, NFκB: Nuclear factor kappa B, ERK: Extracellular signal-regulated kinases and eIF2α:Elongation initiation factor 2α). They may as a result be important in mitigating the severity of COVID-19, acting through the endoplasmic reticulum stress or ACE-Angiotensin-II-AT₁R axis (AT₁R) pathway. Many Nrf2-interacting nutrients are also interacting with TRPA1 and/or TRPV1. Interestingly, geographical areas with very low COVID-19 mortality are those with the lowest prevalence of obesity (Sub-Saharan Africa and Asia). It is tempting to propose that Nrf2-interacting foods and nutrients can re-balance insulin resistance and have a significant effect on COVID-19 severity. It is therefore possible that the intake of these foods may restore an optimal natural balance for the Nrf2 pathway and may be of interest in the mitigation of COVID-19 severity.

Evolution of ferritin levels in hepatitis C patients treated with antivirals

The evolution of ferritin levels in hepatitis C virus (HCV)-infected patients with sustained virological responses (SVRs) following various therapy regimens remains elusive. An 8-year prospective cohort study of 1194 HCV-infected patients [interferon-based therapy (n = 620), direct-acting antiviral agent (DAA) therapy (n = 355)] was conducted. At baseline, sex, alanine aminotransferase (ALT), triglycerides, homeostatic model assessment of insulin resistance (HOMA-IR), estimated glomerular filtration rate (eGFR), hemoglobin, iron/total iron-binding capacity (Fe/TIBC) and IFNL3-rs12979860 genotypes were associated with ferritin levels. At 24 weeks posttherapy, ALT, triglycerides, total cholesterol, eGFR, Fe/TIBC and the therapy regimen were associated with ferritin levels in SVR patients. Among interferon-treated patients, ferritin levels increased at 24 weeks posttherapy, regardless of SVR, and 24-week posttherapy ferritin levels were higher in non-SVR patients (n = 111) than in SVR patients (n = 509); ferritin levels began decreasing at 3 years posttherapy and were lower than pretherapy levels since 4 years posttherapy in SVR patients. Among DAA-treated SVR patients (n = 350), ferritin levels decreased and remained stable since 24 weeks posttherapy. ALT, triglycerides, eGFR, and Fe/TIBC were HCV-unrelated factors associated with ferritin levels; sex, HOMA-IR, total cholesterol, hemoglobin and IFNL3-rs12979860 genotype were HCV-related factors associated with ferritin levels. In interferon-treated SVR patients, the increased trend of posttherapy ferritin levels was not reversed until 4 years posttherapy. In DAA-treated SVR patients, ferritin levels decreased since 24 weeks posttherapy.

Type I Interferons Ameliorate Zinc Intoxication of Candida glabrata by Macrophages and Promote Fungal Immune Evasion

Host and fungal pathogens compete for metal ion acquisition during infectious processes, but molecular mechanisms remain largely unknown. Here, we show that type I interferons (IFNs-I) dysregulate zinc homeostasis in macrophages, which employ metallothionein-mediated zinc intoxication of pathogens as fungicidal response. However, Candida glabrata can escape immune surveillance by sequestering zinc into vacuoles. Interestingly, zinc-loading is inhibited by IFNs-I, because a Janus kinase 1 (JAK1)-dependent suppression of zinc homeostasis affects zinc distribution in macrophages as well as generation of reactive oxygen species (ROS). In addition, systemic fungal infections elicit IFN-I responses that suppress splenic zinc homeostasis, thereby altering macrophage zinc pools that otherwise exert fungicidal actions. Thus, IFN-I signaling inadvertently increases fungal fitness both in vitro and in vivo during fungal infections. Our data reveal an as yet unrecognized role for zinc intoxication in antifungal immunity and suggest that interfering with host zinc homeostasis may offer therapeutic options to treat invasive fungal infections.

Interferon gamma-induced protein 10 (IP-10) and cardiovascular disease in African Americans

Biomarkers of chronic inflammation (such as C-reactive protein) have long been associated with cardiovascular disease and mortality; however, biomarkers involved in antiviral cytokine induction and adaptive immune system activation remain largely unexamined. We hypothesized the cytokine interferon gamma inducible protein 10 (IP-10) would be associated with clinical and subclinical cardiovascular disease and all-cause mortality in African Americans. We assessed these associations in the Jackson Heart Study (JHS) cohort and the REasons for Geographic and Racial Differences in Stroke (REGARDS) study. There was a modest association of IP-10 with higher odds of left ventricular hypertrophy (OR = 1.20 (95% confidence interval (CI) 1.03, 1.41) per standard deviation (SD) higher natural log-transformed IP-10 in JHS). We did not observe associations with ankle brachial index, intima-media thickness, or arterial calcification. Each SD higher increment of ln-transformed IP-10 concentration was associated with incident heart failure (hazard ratio (HR) 1.26; 95% CI 1.11, 1.42, p = 4x10-4) in JHS, and with overall mortality in both JHS (HR 1.12 per SD, 95% CI 1.03, 1.21, p = 7.5x10-3) and REGARDS (HR 1.31 per SD, 95% CI 1.10, 1.55, p = 2.0 x 10-3), adjusting for cardiovascular risk factors and C-reactive protein. However, we found no association between IP-10 and stroke or coronary heart disease. These results suggest a role of IP-10 in heart failure and mortality risk independent of C-reactive protein. Further research is needed to investigate how the body's response to chronic viral infection may mediate heart failure and overall mortality risk in African Americans.

SHP2 deficiency promotes Staphylococcus aureus pneumonia following influenza infection

Objectives

Secondary bacterial pneumonia is common following influenza infection. However, it remains unclear about the underlying molecular mechanisms.

Materials and methods

We established a mouse model of post‐influenza S aureus pneumonia using conditional Shp2 knockout mice (LysM^Cre/+:Shp2^flox/flox). The survival, bacterial clearance, pulmonary histology, phenotype of macrophages, and expression of type I interferons and chemokines were assessed between SHP2 deletion and control mice (Shp2^flox/flox). We infused additional KC and MIP‐2 to examine the reconstitution of antibacterial immune response in LysM^Cre/+:Shp2^flox/flox mice. The effect of SHP2 on signal molecules including MAPKs (JNK, p38 and Erk1/2), NF‐κB p65 and IRF3 was further detected.

Results

LysM^Cre/+:Shp2^flox/flox mice displayed impaired antibacterial immunity and high mortality compared with control mice in post‐influenza S aureus pneumonia. The attenuated antibacterial ability was associated with the induction of type I interferon and suppression of chemo‐attractants KC and MIP‐2, which reduced the infiltration of neutrophils into the lung upon secondary bacterial invasion. In additional, Shp2 knockout mice displayed enhanced polarization to alternatively activated macrophages (M2 phenotype). Further in vitro analyses consistently demonstrated that SHP2‐deficient macrophages were skewed towards an M2 phenotype and had a decreased antibacterial capacity. Moreover, SHP2 modulated the inflammatory response to secondary bacterial infection via interfering with NF‐κB and IRF3 signalling in macrophages.

Conclusions

Our findings reveal that the SHP2 expression enhances the host immune response and prompts bacterial clearance in post‐influenza S aureus pneumonia.

The Effect of CpG Sequences on Capsid-Specific CD8+ T Cell Responses to AAV Vector Gene Transfer

Transfer of genes by adeno-associated virus (AAV) vectors is benefiting patients with particular genetic defects. Challenges remain by rejection of AAV-transduced cells, which may be caused by CD8⁺ T lymphocytes directed to AAV capsid antigens. Reducing the number of CpG motifs from the genome of AAV vectors reduces expansion of naive T cells directed against an epitope within the capsid. In contrast, AAV capsid-specific memory CD8⁺ T cells respond more vigorously to AAV vectors lacking CpG motifs than to those with CpG motifs presumably reflecting dampening of T cell expansion by cytokines from the innate immune system. Depending on the purification method, AAV vector preparations can contain substantial amounts of empty AAV particles that failed to package the genome. Others have used empty particles as decoys to AAV-neutralizing antibodies. We tested if empty AAV vectors given alone or mixed with genome-containing AAV vectors induce proliferation of naive or memory CD8⁺ T cells directed to an antigen within an AAV capsid. Naive CD8⁺ T cells failed to respond to empty AAV vectors, which in contrast induced expansion of AAV-specific memory CD8⁺ T cells.

Nucleic Acid Induced Interferon and Inflammasome Responses in Regulating Host Defense to Gastrointestinal Viruses

The gut bacterial and fungal communities residing in the gastrointestinal tract have undisputed far-reaching effects in regulating host health. In the meantime, however, metagenomic sequencing efforts are revealing enteric viruses as the most abundant dimension of the intestinal gut ecosystem, and the first gut virome-wide association studies showed that inflammatory bowel disease as well as type 1 diabetes could be linked to the presence or absence of particular viral inhabitants in the intestine. In line with the genetic component of these human diseases, mouse model studies demonstrated how beneficial functions of a resident virus can switch to detrimental inflammatory effects in a genetically predisposed host. Such viral-induced intestinal immune disturbances are also recapitulated by several gastrointestinal infectious viruses such as rotavirus and human norovirus. This wide range of viral effects on intestinal immunity emphasizes the need for understanding the innate immune responses to gastrointestinal viruses. Numerous nucleic acid sensors such as DexD/H helicases and AIM2 serve as cytosolic viral guardians to induce antiviral interferon and/or pro-inflammatory inflammasome responses. In both cases, pioneering examples are emerging in which RNA helicases cooperate with particular Nod-like receptors to trigger these cellular responses to enteric viruses. Here we summarize the reported beneficial versus detrimental effects of enteric viruses in the intestinal immune system, and we zoom in on the mechanisms through which sensing of nucleic acids from these enteric viruses trigger interferon and inflammasome responses.

Ebola viral dynamics in nonhuman primates provides insights into virus immuno-pathogenesis and antiviral strategies

Despite several clinical trials implemented, no antiviral drug could demonstrate efficacy against Ebola virus. In non-human primates, early initiation of polymerase inhibitors favipiravir and remdesivir improves survival, but whether they could be effective in patients is unknown. Here we analyze the impact of antiviral therapy by using a mathematical model that integrates virological and immunological data of 44 cynomolgus macaques, left untreated or treated with favipiravir. We estimate that favipiravir has a ~50% efficacy in blocking viral production, which results in reducing virus growth and cytokine storm while IFNα reduces cell susceptibility to infection. Simulating the effect of delayed initiations of treatment, our model predicts survival rates of 60% for favipiravir and 100% for remdesivir when treatment is initiated within 3 and 4 days post infection, respectively. These results improve the understanding of Ebola immuno-pathogenesis and can help optimize antiviral evaluation in future outbreaks.

Sexual Dimorphism of Immune Responses: A New Perspective in Cancer Immunotherapy

Nowadays, several types of tumors can benefit from the new frontier of immunotherapy, due to the recent increasing knowledge of the role of the immune system in cancer control. Among the new therapeutic strategies, there is the immune checkpoint blockade (ICB), able to restore an efficacious antitumor immunity and significantly prolong the overall survival (OS) of patients with advanced tumors such as melanoma and non-small cell lung cancer (NSCLC). Despite the impressive efficacy of these agents in some patients, treatment failure and resistance are frequently observed. In this regard, the signaling governed by IFN type I (IFN-I) has emerged as pivotal in orchestrating host defense. This pathway displays different activation between sexes, thus potentially contributing to sexual dimorphic differences in the immune responses to immunotherapy. This perspective article aims to critically consider the immune signals, with particular attention to IFN-I, that may differently affect female and male antitumor responses upon immunotherapy.

Sexual Dimorphism of Immune Responses: A New Perspective in Cancer Immunotherapy

Nowadays, several types of tumors can benefit from the new frontier of immunotherapy, due to the recent increasing knowledge of the role of the immune system in cancer control. Among the new therapeutic strategies, there is the immune checkpoint blockade (ICB), able to restore an efficacious antitumor immunity and significantly prolong the overall survival (OS) of patients with advanced tumors such as melanoma and non-small cell lung cancer (NSCLC). Despite the impressive efficacy of these agents in some patients, treatment failure and resistance are frequently observed. In this regard, the signaling governed by IFN type I (IFN-I) has emerged as pivotal in orchestrating host defense. This pathway displays different activation between sexes, thus potentially contributing to sexual dimorphic differences in the immune responses to immunotherapy. This perspective article aims to critically consider the immune signals, with particular attention to IFN-I, that may differently affect female and male antitumor responses upon immunotherapy.

Npro His49 and Erns Lys412 mutations in pig bovine viral diarrhea virus type 2 synergistically enhance the cellular antiviral response

Type I interferons are major components of the innate immune response of hosts, and accordingly, many viruses have evolved mechanisms to modulate the host response during infection. Bovine viral diarrhea virus (BVDV) nonstructural protein N^pro and structural protein E^rns play important roles in inhibiting type I interferon. The aim of this study was to explore the epistatic effects of amino acid mutations in N^pro and E^rns in porcine ST cells to characterize the immune response induced by BVDV-2. Plasmids with mutant amino acids His49 (H49), Glu22 (E22) in N^pro, and His300 (H300), Lys412 (K412) in E^rns which had been changed to Alanine (A) had similar effects on type I interferon production in MDBK and ST cells, but resulted in much greater ISG15, OAS, and Mx production in ST cells. The rescued vASH/N^proH49E^rnsK412 virus showed the best efficiency with respect to modulating antiviral cytokines, indicating that the amino acids N^pro H49 and E^rns K412 had highly synergistic effects in abolishing the ability to inhibit type I interferon. These findings have importance practical implications owing to the increasing prevalence of BVDV infections, including persistent infections, in domestic pigs.