IFN-λ3 inhibits HIV infection of macrophages through the JAK-STAT pathway

The potential of IFN-λ, IL-32γ, IL-6, and IL-22 as safeguards against human viruses: a systematic review and a meta-analysis

Many studies have investigated the antiviral activity of cytokines, including interleukin-6 (IL-6), interleukin-22 (IL-22), interleukin-32 gamma (IL-32γ), and interferon-lambda (IFN-λ) in diverse populations. This study aims to evaluate the role of these cytokines in inhibition of various human and animal viruses when administered exogenously. A comprehensive meta-analysis and systematic review were conducted on all the relevant studies from three databases. Standard mean differences (SMDs) of overall viral inhibition were used to generate the difference in the antiviral efficacy of these cytokines between control and experimental groups. A total of 4,618 abstracts for IL-6, 3,517 abstracts for IL-22, 2,160 abstracts for IL-32γ, and 1,026 abstracts for IFN-λ were identified, and 7, 4, 8, and 35 studies were included, respectively, for each cytokine. IFN-λ (SMD = 0.9540; 95% CI: 0.69-0.22) and IL-32γ (SMD = 0.459; 95% CI: 0.02-0.90) showed the highest influence followed by IL-6 (SMD = 0.456; CI: -0.04-0.95) and IL-22 (SMD = 0.244; 95% CI: -0.33-0.81). None of the cytokines represented heterogeneity (tau² > 0), but only IFN-λ indicated the funnel plot asymmetry (p = 0.0097). Results also indicated that IFN-λ and IL-32γ are more potent antivirals than IL-6 and IL-22. The collective findings of this study emphasize that exogenously administered pro-inflammatory cytokines, specifically IFN-λ and IL-32, exhibit a significant antiviral activity, thereby underscoring them as potent antiviral agents. Nonetheless, additional research is required to ascertain their clinical utility and potential for integration into combinatorial therapeutic regimens against viral infections.

Activation of Toll-like receptor 3 inhibits HIV infection of human iPSC-derived microglia

As a key immune cell in the brain, microglia are essential for protecting the central nervous system (CNS) from viral infections, including HIV. Microglia possess functional Toll-like receptor 3 (TLR3), a key viral sensor for activating interferon (IFN) signaling pathway-mediated antiviral immunity. We, therefore, studied the effect of poly (I:C), a synthetic ligand of TLR3, on the activation of the intracellular innate immunity against HIV in human iPSC-derived microglia (iMg). We found that poly (I:C) treatment of iMg effectively inhibits HIV infection/replication at both mRNA and protein levels. Investigations of the mechanisms revealed that TLR3 activation of iMg by poly (I:C) induced the expression of both type I and type III IFNs. Compared with untreated cells, the poly (I:C)-treated iMg expressed significantly higher levels of IFN-stimulated genes (ISGs) with known anti-HIV activities (ISG15, MxB, Viperin, MxA, and OAS-1). In addition, TLR3 activation elicited the expression of the HIV entry coreceptor CCR5 ligands (CC chemokines) in iMg. Furthermore, the transcriptional profile analysis showed that poly (I:C)-treated cells had the upregulated IFN signaling genes (ISG15, ISG20, IFITM1, IFITM2, IFITM3, IFITM10, APOBEC3A, OAS-2, MxA, and MxB) and the increased CC chemokine signaling genes (CCL1, CCL2, CCL3, CCL4, and CCL15). These observations indicate that TLR3 is a potential therapy target for activating the intracellular innate immunity against HIV infection/replication in human microglial cells. Therefore, further studies with animal models and clinical specimens are necessary to determine the role of TLR3 activation-driven antiviral response in the control and elimination of HIV in infected host cells.

Interferon Family Cytokines in Obesity and Insulin Sensitivity

Obesity and its associated complications are global public health concerns. Metabolic disturbances and immune dysregulation cause adipose tissue stress and dysfunction in obese individuals. Immune cell accumulation in the adipose microenvironment is the main cause of insulin resistance and metabolic dysfunction. Infiltrated immune cells, adipocytes, and stromal cells are all involved in the production of proinflammatory cytokines and chemokines in adipose tissues and affect systemic homeostasis. Interferons (IFNs) are a large family of pleiotropic cytokines that play a pivotal role in host antiviral defenses. IFNs are critical immune modulators in response to pathogens, dead cells, and several inflammation-mediated diseases. Several studies have indicated that IFNs are involved in the pathogenesis of obesity. In this review, we discuss the roles of IFN family cytokines in the development of obesity-induced inflammation and insulin resistance.

Effect of cannabidiol on apoptosis and cellular interferon and interferon-stimulated gene responses to the SARS-CoV-2 genes ORF8, ORF10 and M protein

AIMS

To study effects on cellular innate immune responses to ORF8, ORF10, and Membrane protein (M protein) from the Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes COVID-19, in combination with cannabidiol (CBD).

MAIN METHODS

HEK293 cells transfected with plasmids expressing control vector, ORF8, ORF10, or M protein were assayed for cell number and markers of apoptosis at 24 h, and interferon and interferon-stimulated gene expression at 14 h, with or without CBD. Cells transfected with polyinosinic:polycytidylic acid (Poly (I:C)) were also studied as a general model of RNA-type viral infection.

KEY FINDINGS

Reduced cell number and increased early and late apoptosis were found when expression of viral genes was combined with 1-2 μM CBD treatment, but not in control-transfected cells treated with CBD, or in cells expressing viral genes but treated only with vehicle. In cells expressing viral genes, CBD augmented expression of IFNγ, IFNλ1 and IFNλ2/3, as well as the 2'-5'-oligoadenylate synthetase (OAS) family members OAS1, OAS2, OAS3, and OASL. CBD also augmented expression of these genes in control cells not expressing viral genes, but without enhancing apoptosis. CBD similarly enhanced the cellular anti-viral response to Poly (I:C).

SIGNIFICANCE

Our results demonstrate a poor ability of HEK293 cells to respond to SARS-CoV-2 genes alone, but an augmented innate anti-viral response to these genes in the presence of CBD. Thus, CBD may prime components of the innate immune system, increasing readiness to respond to RNA-type viral infection without activating apoptosis, and could be studied for potential in prophylaxis.

Type III Interferons: Emerging Roles in Autoimmunity

Type III interferons (IFNs) or the lambda IFNs (IFNLs or IFN-λs) are antimicrobial cytokines that play key roles in immune host defense at endothelial and epithelial barriers. IFNLs signal via their heterodimeric receptor, comprised of two subunits, IFNLR1 and interleukin (IL)10Rβ, which defines the cellular specificity of the responses to the cytokines. Recent studies show that IFNL signaling regulates CD4+ T cell differentiation, favoring Th1 cells, which has led to the identification of IFNL as a putative therapeutic target for autoimmune diseases. Here, we summarize the IFNL signaling pathways during antimicrobial immunity, IFNL-mediated immunomodulation of both innate and adaptive immune cells, and induction of autoimmunity.

Exosomes Transport Anti-Human Immunodeficiency Virus Factors from Human Cervical Epithelial Cells to Macrophages

The female reproductive tract (FRT) is a major site of HIV sexual transmission. As the outermost layer of cells in the FRT, the human cervical epithelial cells (HCEs) have direct contact with HIV or infected cells. Our early work showed that supernatant (SN) from TLR3-activated HCEs contain the antiviral factors that could potently inhibit HIV replication in macrophages. However, it remains to be determined how HCEs transport the anti-HIV factors to macrophages. This follow-up study examined the role of exosomes in HCE-mediated anti-HIV activity. We found that TLR3 activation of HCEs resulted in the release of exosomes that contained multiple IFN-stimulated genes (ISGs: ISG56, OAS1, MxA, and Mx2) and the HIV restriction microRNAs (miR-28, miR-29 family members, miR-125b, miR-150, miR-382, miR-223, miR-20a, and miR-198). The depletion of exosomes from SN of TLR3-activated HCEs diminished HCE-mediated anti-HIV activity in macrophages, indicating that HCE-derived exosomes are responsible for transporting the antiviral molecules to macrophages. These in vitro findings suggest a novel antiviral mechanism by which HCEs participate in the FRT innate immunity against HIV infection. Further in vivo studies are necessary in order to develop an exosome-based delivery system for prevention and treatment of HIV infection through sexual transmission.

Interferon lambda in inflammation and autoimmune rheumatic diseases

Interferons are potent antiviral cytokines that modulate immunity in response to infection or other danger signals. In addition to their antiviral functions, type I interferons (IFNα and IFNβ) are important in the pathogenesis of autoimmune diseases. Type III interferons (IFNλs) were initially described as a specialized system that inhibits viral replication at epithelial barrier surfaces while limiting inflammatory damage. However, evidence now suggests that type III interferons have complex effects on both innate and adaptive immune responses and might also be pathogenic in systemic autoimmune diseases. Concentrations of IFNλs are increased in blood and tissues in a number of autoimmune rheumatic diseases, including systemic lupus erythematosus, and are further associated with specific clinical and laboratory parameters. This Review is aimed at providing a critical evaluation of the current literature on IFNλ biology and how type III interferons might contribute to immune dysregulation and tissue damage in autoimmunity. The potential effects of type III interferons on treatment strategies for autoimmune rheumatic diseases, such as interferon blockade, are also considered.

Porcine interferon lambda 3 (IFN-λ3) shows potent anti-PRRSV activity in primary porcine alveolar macrophages (PAMs)

Background

Porcine reproductive and respiratory syndrome virus (PRRSV) is a serious viral disease of swine. At present, there are vaccines for the control of PRRSV infection, but the effect is not satisfactory. The recombination of attenuated vaccines causes significant difficulties with the prevention and control of PRRSV. Type III interferons (IFNs), also called IFN-λs, were newly identified and showed potent antiviral activity within the mucosal surface and immune organs.

Results

Therefore, primary porcine alveolar macrophages (PAMs) were used for this investigation. To this end, we found that the replication of PRRSV in PAMs was significantly reduced after pre-treatment with IFN-λ3, and such inhibition was dose- and time-dependent. The plaque formation of PRRSV abrogated entirely, and virus yields were reduced by four orders of magnitude when the primary PAMs were treated with IFN-λ3 at 1000 ng/ml. In addition, IFN-λ3 in our study was able to induce the expression of interferon-stimulated genes 15 (ISG15), 2′-5′-oligoadenylate synthase 1 (OAS1), IFN-inducible transmembrane 3 (IFITM3), and myxoma resistance protein 1(Mx1) in primary PAMs.

Conclusions

IFN-λ3 had antiviral activity against PRRSV and can stimulate the expression of pivotal interferon-stimulated genes (ISGs), i.e., ISG15, Mx1, OAS1, and IFITM3. So, IFN-λ3 may serve as a useful antiviral agent.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-020-02627-6.

Association between interferon lambda 3 rs12979860 polymorphism and clinical outcome in dengue virus-infected children

Single nucleotide polymorphisms (SNPs) in immune-related genes have been shown to play a role in driving the development of the severe phenotypes of dengue virus (DENV) infection. We assessed the association between IFNL3 gene SNP (rs12979860) and dengue clinical outcomes in children. Patients with dengue-related symptoms (aged 1-15 years) admitted at a public hospital in Northeast Brazil were invited to participate. The association between rs12979860 polymorphism and dengue classification and clinical signs and symptoms were analysed. A total of 206 DENV-infected children were included: 53.4% of the infections were classified as severe dengue. The T allele carriers had higher risk of developing severe dengue when compared to CC genotype carriers (OR: 1.81; 95% CI: 0.98-3.32 p = .054). The T allele carriers also showed longer fever episodes when compared to patients with the CC genotype (OR: 1.90; 95%CI: 1.07-3.38; p = .027). On the other hand, the ones carrying the CT/TT genotype had 70% lower chance of developing thrombocytopenia when compared to those with the CC genotype (OR: 0.30; 95%CI: 0.08-0.88; p = .042). Our findings demonstrated that the T allele carriers of the IFNL3 gene had higher risk of developing severe dengue, suggesting a link between IFN-λ expression and DENV immunopathogenesis.

Lack of Association between IFNL3 Polymorphism and Human Papillomavirus Infection and Their Progression in HIV-Infected Women Receiving Antiretroviral Treatment

BACKGROUND

It has been reported that interferon-λ3 (IFNL3)might influence the pathogenesis and clearance of human papillomavirus (HPV) infection. The impact of IFNL3 single-nucleotide polymorphism (SNP) on HPV infection is currently unknown. The aim of this study was to investigate the association between variants in the IFNL3 region and HPV infection in women with human immunodeficiency virus (HIV) infection.

METHODS

A total of 236 HIV patients, including 65 HPV-negative and 171 HPV DNA-positive women, were enrolled into this study. The IFNL3 rs12979860 polymorphism was genotyped using a predesigned TaqMan SNP genotyping assay.

RESULTS

Data showed no significant differences in genotypes or allele frequencies between the HPV DNA-positive and the HPV-negative women (p > 0.05). After dividing the HPV-positive women according to cytology results into patients with abnormal and normal lesions, the genotype and allele distribution of the SNP did not significantly differ between the 2 groups (p > 0.05).

CONCLUSIONS

Our results showed that the IFNL3 rs12979860 polymorphism is not a major determinant of the susceptibility to HPV infection and their progression to abnormal cervical lesions in women living with HIV.

Transcriptome analysis reveals the regulation of the shrimp STAT on host chitin-binding domain containing proteins and energy metabolism process during WSSV infection

JAK/STAT signaling pathway is suggested to enhance the infection of WSSV in crustaceans. However, the regulation mechanism of this process is not quite clear. Here, comparative transcriptomic analysis was performed among shrimps before and after Litopenaeus vannamei STAT (LvSTAT) was silenced by dsRNA approach during WSSV infection. Differentially expressed genes (DEGs) common in the STAT-interfered groups and control groups at different times after WSSV infection were analyzed to acquire the genes probably regulated by LvSTAT. DEGs annotation and further GO terms enrichment analyses revealed that the identified DEGs mainly contained two categories, chitin-binding domain containing proteins and energy metabolism related genes. The former mainly included cuticle proteins, thrombospondins (TSPs) and peritrophin, while the later mainly included hexose catabolic process and glycolysis related genes. Two cuticle proteins and two TSPs were further studied to learn their expression changes during WSSV infection. They were significantly regulated during WSSV infection, implying the involvement of chitin-binding domain containing protein in the invasion process of WSSV. Systematic analysis on the glycolysis and lipid synthesis pathway demonstrated that silencing of LvSTAT could reduce the glycolysis efficiency and the production of lipids. It could be speculated that a favorable function of LvSTAT for WSSV replication existed by regulating the energy metabolism of the host. Through revealing the main category of genes and biological processes regulated by STAT, our study could shed new light on the roles of JAK/STAT signaling pathway in shrimp during virus infection.

Differential expression of interferon-lambda receptor 1 splice variants determines the magnitude of the antiviral response induced by interferon-lambda 3 in human immune cells

Type III interferons (IFN-lambdas(λ)) are important cytokines that inhibit viruses and modulate immune responses by acting through a unique IFN-λR1/IL-10RB heterodimeric receptor. Until now, the primary antiviral function of IFN-λs has been proposed to be at anatomical barrier sites. Here, we examine the regulation of IFN-λR1 expression and measure the downstream effects of IFN-λ3 stimulation in primary human blood immune cells, compared with lung or liver epithelial cells. IFN-λ3 directly bound and upregulated IFN-stimulated gene (ISG) expression in freshly purified human B cells and CD8+ T cells, but not monocytes, neutrophils, natural killer cells, and CD4+ T cells. Despite similar IFNLR1 transcript levels in B cells and lung epithelial cells, lung epithelial cells bound more IFN-λ3, which resulted in a 50-fold greater ISG induction when compared to B cells. The reduced response of B cells could be explained by higher expression of the soluble variant of IFN-λR1 (sIFN-λR1), which significantly reduced ISG induction when added with IFN-λ3 to peripheral blood mononuclear cells or liver epithelial cells. T-cell receptor stimulation potently, and specifically, upregulated membrane-bound IFNLR1 expression in CD4+ T cells, leading to greater antiviral gene induction, and inhibition of human immunodeficiency virus type 1 infection. Collectively, our data demonstrate IFN-λ3 directly interacts with the human adaptive immune system, unlike what has been previously shown in published mouse models, and that type III IFNs could be potentially utilized to suppress both mucosal and blood-borne viral infections.

Host Genetic Determinants of Hepatitis B Virus Infection

Chronic hepatitis B virus (HBV) infection is still a major health problem worldwide. Recently, a great number of genetic studies based on single nucleotide polymorphisms (SNPs) and genome-wide association studies have been performed to search for host determinants of the development of chronic HBV infection, clinical outcomes, therapeutic efficacy, and responses to hepatitis B vaccines, with a focus on human leukocyte antigens (HLA), cytokine genes, and toll-like receptors. In addition to SNPs, gene insertions/deletions and copy number variants are associated with infection. However, conflicting results have been obtained. In the present review, we summarize the current state of research on host genetic factors and chronic HBV infection, its clinical type, therapies, and hepatitis B vaccine responses and classify published results according to their reliability. The potential roles of host genetic determinants of chronic HBV infection identified in these studies and their clinical significance are discussed. In particular, HLAs were relevant for HBV infection and pathogenesis. Finally, we highlight the need for additional studies with large sample sizes, well-matched study designs, appropriate statistical methods, and validation in multiple populations to improve the treatment of HBV infection.

The generation and biological activity of a long-lasting recombinant human interferon-λ1

The previously generated recombinant human (rh) interferon (IFN)-λ1 protein has a short half-life, and this feature makes it challenging to conduct studies on potential clinical applications for rhIFN-λ1. In an attempt to overcome this difficulty, we constructed a 'long-life' version of rhIFN-λ1. This modified rhIFN-λ1, named rhIFN-λ1-CTPON, has a human chorionic gonadotropin β subunit carboxyl-terminal peptide (CTP) and an N-glycosylation sequence linked to its C-terminus. We confirmed the sequence of rhIFN-λ1-CTPON by mass spectrometry and then measured its biological activities. The results show that rhIFN-λ1-CTPON had antiviral activity and anti-proliferation activity in vitro that were similar to those of rhIFN-λ1 and that it similarly promoted natural killer cell cytotoxicity. Notably, the in vivo half-life of rhIFN-λ1-CTPON was determined to be 3-fold higher than that of rhIFN-λ1. We also assessed the anti-hepatitis B virus activity of rhIFN-λ1-CTPON; it was able to inhibit the production of the antigens HBs-Ag and HBe-Ag and induce antiviral gene expression. In conclusion, rhIFN-λ1-CTPON has a longer half-life than rhIFN-λ1 and has similar biological activities, so rhIFN-λ1-CTPON is an appropriate substitute for rhIFN-λ1 in the further study of potential clinical applications for rhIFN- λ1.

Comprehensive Proteomics Identification of IFN-λ3-regulated Antiviral Proteins in HBV-transfected Cells

Interferon lambda (IFN-λ) is a relatively unexplored, yet promising antiviral agent. IFN-λ has recently been tested in clinical trials of chronic hepatitis B virus infection (CHB), with the advantage that side effects may be limited compared with IFN-α, as IFN-λ receptors are found only in epithelial cells. To date, IFN-λ's downstream signaling pathway remains largely unelucidated, particularly via proteomics methods. Here, we report that IFN-λ3 inhibits HBV replication in HepG2.2.15 cells, reducing levels of both HBV transcripts and intracellular HBV DNA. Quantitative proteomic analysis of HBV-transfected cells was performed following 24-hour IFN-λ3 treatment, with parallel IFN-α2a and PBS treatments for comparison using a dimethyl labeling method. The depth of the study allowed us to map the induction of antiviral proteins to multiple points of the viral life cycle, as well as facilitating the identification of antiviral proteins not previously known to be elicited upon HBV infection (e.g. IFITM3, XRN2, and NT5C3A). This study also shows up-regulation of many effectors involved in antigen processing/presentation indicating that this cytokine exerted immunomodulatory effects through several essential molecules for these processes. Interestingly, the 2 subunits of the immunoproteasome cap (PSME1 and PSME2) were up-regulated whereas cap components of the constitutive proteasome were down-regulated upon both IFN treatments, suggesting coordinated modulation toward the antigen processing/presentation mode. Furthermore, in addition to confirming canonical activation of interferon-stimulated gene (ISG) transcription through the JAK-STAT pathway, we reveal that IFN-λ3 restored levels of RIG-I and RIG-G, proteins known to be suppressed by HBV. Enrichment analysis demonstrated that several biological processes including RNA metabolism, translation, and ER-targeting were differentially regulated upon treatment with IFN-λ3 versus IFN-α2a. Our proteomic data suggests that IFN-λ3 regulates an array of cellular processes to control HBV replication.

IFN-λ4 inhibits HIV infection of macrophages through signalling of IFN-λR1/IL-10R2 receptor complex

The recently discovered IFN‐λ4 has been found to have antiviral activity against several viruses. However, it's unknown whether IFN‐λ4 can inhibit HIV infection. Here, we show that IFN‐λ4 could suppress HIV infection of macrophages. This IFN‐λ4‐mediated HIV inhibition was compromised by the antibodies against IFN‐λ receptor complex, IFN‐λR1/IL‐10R2. IFN‐λ4 enhanced the phosphorylation of STAT1, and induced antiviral interferon‐stimulated genes. These findings indicated that IFN‐λ4 can inhibit HIV via JAK/STAT signalling pathway.

Limiting Respiratory Viral Infection by Targeting Antiviral and Immunological Functions of BST-2/Tetherin: Knowledge and Gaps

Recent findings regarding the cellular biology and immunology of BST-2 (also known as tetherin) indicate that its function could be exploited as a universal replication inhibitor of enveloped respiratory viruses (e.g., influenza, respiratory syncytial virus, etc.). BST-2 inhibits viral replication by preventing virus budding from the plasma membrane and by inducing an antiviral state in cells adjacent to infection via unique inflammatory signaling mechanisms. This review presents the first comprehensive summary of what is currently known about BST-2 anti-viral function against respiratory viruses, how these viruses construct countermeasures to antagonize BST-2, and how BST-2 function might be targeted to develop therapies to treat respiratory virus infections. The authors address the current gaps in knowledge, including the need for mechanistic understanding of BST-2 antagonism by respiratory viruses, that should be bridged to achieve that goal.

Immune Evasion of Enteroviruses Under Innate Immune Monitoring

As a major component of immunological defense against a great variety of pathogens, innate immunity is capable of activating the adaptive immune system. Viruses are a type of pathogen that proliferate parasitically in cells and have multiple strategies to escape from host immune pressure. Here, we review recent studies of the strategies and mechanisms by which enteroviruses evade innate immune monitoring.

IFN-λs inhibit Hantaan virus infection through the JAK-STAT pathway and expression of Mx2 protein

Hantaan virus (HTNV), member of the newly defined Hantaviridae family, within the order Bunyavirales, can cause a hemorrhagic fever with renal syndrome with high fatality rates in humans. However, no specific antiviral agents are currently available for HTNV infection approved by the US Food and Drug Administration. Although interferon lambdas (IFN-λs) have been shown to induce an antiviral state against HTNV, the molecular mechanisms remain to be determined. In this study, we found that IFN-λs exerted its anti-HTNV effect by activating Janus kinase/signal transducers and activators of transcription (JAK-STAT) pathway-mediated antiviral immunity in A549 cells. Simultaneously, IFN-λs downregulated suppressor of cytokine signaling proteins, which are the known negative feedback regulators of the JAK-STAT signaling pathway. Additionally, we demonstrated the role of IFN-λs-induced myxovirus resistance 2 (Mx2, also known as MxB) protein as a potential inhibitor for HTNV infection. These findings indicate that IFN-λs play an important role in cellular defenses against HTNV infection at an early stage and that human Mx2 may represent a potential therapeutic target for HTNV infection.

Interferon-associated therapies toward HIV control: The back and forth

Human immunodeficiency virus (HIV) induces a persistent and incurable infection. However, the combined antiretroviral treatment (cART) has markedly changed the evolution of the infection and transformed a deadly disease into a manageable chronic infection. Withdrawal of cART generally leads though to resumption of the viral replication. The eradication of the virus from its cellular and anatomical reservoirs remains a goal-to-achieve for a cure. In this context, developing novel therapies contributing to this aim are an important field of research. Type I IFN has antiviral activity, which, before the presence of efficient anti-HIV drugs, has led to the testing of IFN-based therapeutic strategies during the early years of the pandemic. A historical overview of the results and its limitations that were put into light are reviewed here. In addition, several lessons could be drawn. For instance, the efficacy of the IFN-I depends on the timing of its administration and the context. Thus, the persistence of an endogenous IFN-signature, such as that generally observed in viremic patients, seems to be associated with a lower efficacy of IFN. Based on the lessons from previous trials, and in the context of cART and research for a cure, type I Interferon has regained interest and novel therapeutic approaches are currently tested in combination with cART, some with disappointing, other with encouraging results with regard to a reduction in the size of the HIV reservoir and/or delays in viral rebound after cessation of cART. Additional strategies are currently developed in addition to improve the antiviral function of the IFN-I, by using for instance other IFN subtypes than IFN-Iα2. In parallel, the development of innovative strategies aimed at counteracting the excessive activation of the IFN-pathways have been continued and their results are reviewed here as well. Altogether, the use of IFN-I in anti-HIV therapies has gone through distinct phases and many lessons could be drawn. Novel combinations are currently be tested that might provide interesting results.

Interleukin gene polymorphisms and susceptibility to HIV-1 infection: a meta-analysis

Some subjects are repeatedly exposed to human immunodeficiency virus (HIV), yet they remain uninfected. This suggests the existence of host-resistance mechanisms. The current study synthesizes the evidence regarding the association between interleukin (IL) gene polymorphisms and HIV susceptibility. Medline, Scopus and the Web of Science databases were systematically searched, and a meta-analysis of case-control studies was conducted. Univariate and bivariate methods were used. The literature search identified 42 eligible studies involving 15,727 subjects. Evidence was obtained on eight single-nucleotide polymorphisms (SNPs): IL1A -889 C>T (rs1800587), IL1B +3953/4 C>T (rs1143634), IL4 -589/90 C>T (rs2243250), IL6 -174 G>C (rs1800795), IL10 -592 C>A (rs1800872), IL10-1082 A>G (rs1800896), IL12B -1188 A>C (rs3212227) and IL28B C>T (rs12979860). The IL1B +3953/4 C>T variant appears to increase the risk of HIV acquisition, under the assumption of a recessive genetic model (odds ratio (OR): 4.47, 95% CI: 2.35-8.52). The AA homozygotes of the IL10 -592 C>A SNP had an increased, marginally nonsignificant, risk (OR: 1.39, 95% CI: 0.97-2.01). It reached, however, significance in sub analyses (OR: 1.49, 95% CI: 1.04-2.12). Finally, the well-studied hepatitis C virus (HCV) infection IL28B (rs12979860) CT/TT genotypes were associated with a 27% decrease in HIV infection risk, especially in populations infected with HCV (OR: 0.73, 95% CI: 0.57-0.95). Interleukin signalling is perhaps important in HIV infection and some interleukin genetic variants may affect the risk of HIV acquisition. Approaches targeting specific genes and genome wide association studies should be conducted to decipher the effect of these polymorphisms.

Human Intestinal Epithelial Cells Release Antiviral Factors That Inhibit HIV Infection of Macrophages

As a rich source of CD4⁺ T cells and macrophages, the gastrointestinal (GI) tract is a major target site for HIV infection. The interplay between GI-resident macrophages and intestinal epithelial cells (IECs) constitutes an important element of GI innate immunity against pathogens. In this study, we investigated whether human IECs have the ability to produce antiviral factors that can inhibit HIV infection of macrophages. We demonstrated that IECs possess functional toll-like receptor 3 (TLR3), the activation of which resulted in induction of key interferon (IFN) regulatory factors (IRF3 and IRF7), IFN-β, IFN-λ, and CC chemokines (MIP-1α, MIP-1β, RANTES), the ligands of HIV entry co-receptor CCR5. In addition, TLR3-activated IECs release exosomes that contained the anti-HIV factors, including IFN-stimulated genes (ISGs: ISG15, ISG56, MxB, OAS-1, GBP5, and Viperin) and HIV restriction miRNAs (miRNA-17, miRNA-20, miRNA-28, miRNA-29 family members, and miRNA-125b). Importantly, treatment of macrophages with supernatant (SN) from the activated IEC cultures inhibited HIV replication. Further studies showed that IEC SN could also induce the expression of antiviral ISGs and cellular HIV restriction factors (Tetherin and APOBEC3G/3F) in HIV-infected macrophages. These findings indicated that IECs might act as an important element in GI innate immunity against HIV infection/replication.

Interleukin 28B rs12979860 genotype and Human Immunodeficiency Virus type 1: Susceptibility, AIDS development and therapeutic outcome

Human Immunodeficiency Virus type 1 (HIV-1) infection and progression varies widely among individuals. Interferon-λ3 exerts anti-HIV function by activating JAK/STAT pathway-mediated innate immunity. Therefore, we aimed to investigate the association between single nucleotide polymorphisms of the interleukin 28B (IL28B) gene, and the risk of acquisition, AIDS development and therapeutic outcome of HIV-1 in a Moroccan population. A total of 266 HIV-1 seropositive and 158 HIV-1 seronegative subjects were enrolled. Genotyping of rs12979860 of the IL28B was performed using a predesigned TaqMan SNP genotyping assay. No significant association was found between IL28B rs12979860 polymorphism and susceptibility to HIV-1 infection and AIDS development (p > .05). However, in HIV-1 treated patients carrying CC genotype had a more pronounced high levels of CD4+ T-cell compared to subjects with TT genotype (p = .0004). Interestingly, regarding HIV-1 viral load no significant differences between IL28B genotypes in treated and untreated patients were observed (p < .05). IL28B rs12979860 polymorphism not influences the susceptibility to HIV-1 and the AIDS development. However, this polymorphism may affect the response to treatment as measured by CD4+ T cell counts.

Interferon Lambda Genetics and Biology in Regulation of Viral Control

Type III interferons, also known as interferon lambdas (IFNλs), are the most recent addition to the IFN family following their discovery in 2003. Initially, IFNλ was demonstrated to induce expression of interferon-stimulated genes and exert antiviral properties in a similar manner to type I IFNs. However, while IFNλ has been described to have largely overlapping expression and function with type I IFNs, it has become increasingly clear that type III IFNs also have distinct functions from type I IFNs. In contrast to type I IFNs, whose receptor is ubiquitously expressed, type III IFNs signal and function largely at barrier epithelial surfaces, such as the respiratory and gastrointestinal tracts, as well as the blood–brain barrier. In further support of unique functions for type III IFNs, single nucleotide polymorphisms in IFNL genes in humans are strongly associated with outcomes to viral infection. These biological linkages have also been more directly supported by studies in mice highlighting roles of IFNλ in promoting antiviral immune responses. In this review, we discuss the current understanding of type III IFNs, and how their functions are similar to, and different from, type I IFN in various immune cell subtypes and viral infections.

Effect of Interleukin-28B polymorphism on Interleukin-28 expression and immunological recovery amongst HIV-1-infected individuals following antiretroviral therapy

PURPOSE

Type III interferon is well known to have diverse antiviral and immunomodulatory activities. Studies describing the association of interleukin (IL)-28 polymorphisms in treatment-experienced HIV participants are limited. This study was aimed to determine the association of IL-28B gene polymorphisms with immunological recovery in HIV patients on 6-9 months of antiretroviral therapy (ART).

METHODS

Eighty treatment-naive HIV patients were recruited, of which 48 patients were followed up after 6-9 months of ART. Whole blood samples were collected before and after 6-9 months of ART. CD4, CD8 and CD3 counts were enumerated flow cytometry. IL-28B polymorphisms (rs12979860 and rs8099917) were profiled by polymerase chain reaction (PCR)-restriction fragment length polymorphism. The IL-28 mRNA and plasma HIV-1 viral load were estimated using real-time PCR and plasma IL-28 level by ELISA.

RESULTS

The CD4, CD4/CD3%, IL-28 mRNA and reversal of CD4/CD8 ratio were significantly increased following 6-9 months of ART (P < 0.01). The rs12979860 CC genotype and rs12979860:rs8099917 (CC: TT) haplotype showed significant association with higher CD4+ T-cell count amongst treatment-naive HIV-infected individuals (P < 0.05). In addition, there was a significant association of rs12979860 CC genotype with increase in CD4/CD3% following 6-9 months of ART. IL-28 mRNA showed correlation with the HIV-1 viral load, and there was a significant increase in the IL-28 mRNA expression following 6-9 months of ART.

CONCLUSION

Our preliminary findings suggest that IL-28 polymorphisms could influence both immunological recovery and therapeutic response in HIV infection. Hence, functional studies are warranted to understand the mechanistic basis of IL-28-mediated host genetic influence on HIV therapeutic response.

Type 1 Diabetes and Type 1 Interferonopathies: Localization of a Type 1 Common Thread of Virus Infection in the Pancreas

Type 1 diabetes (T1D) has been associated with both genetic and environmental factors. Increasing incidence of T1D worldwide is prompting researchers to adopt different approaches to explain the biology of T1D, beyond the presence and activity of autoreactive lymphocytes. In this review, we propose inflammatory pathways as triggers for T1D. Within the scope of those inflammatory pathways and in understanding the pathogenesis of disease, we suggest that viruses, in particular Coxsackieviruses, act by causing a type 1 interferonopathy within the pancreas and the microenvironment of the islet. As such, this connection and common thread represents an exciting platform for the development of new diagnostic, treatment and/or prevention options.

The dynamic changes of interferon lambdas related genes and proteins in JAK/STAT pathway in both acute and chronic HIV-1 infected patients

BACKGROUND

Host immune responses during acute HIV-1 infection can influence the viral setpoint, which is a predictor of disease progression. Interferon (IFN)-lambdas are newly classified type III interferons, which use JAK-STAT pathway. Currently, the dynamics of IFN-lambdas related genes and proteins expression in the signaling pathway have not been well elaborated, especially in acute HIV-1-infected patients.

OBJECTIVES

To evaluate the dynamic changes of IFN-lambdas related genes and proteins in JAK/STAT pathway in acute HIV-1-infected patients, and analyze their correlation with CD4 T cell counts and HIV-1 viral loads.

STUDY DESIGN

Real-time PCR and flow cytometry methods were used to evaluate the dynamic changes of IFN-lambdas related genes and proteins in JAK/STAT pathway in both acute and chronic HIV-1-infected patients.

RESULTS

The IFN-alpha receptors (R), IFN-gamma R, IFN-lambdas R and STAT1 mRNA and protein levels increased in acute HIV-1-infected patients (p < 0.01), in addition, Mx1 mRNA levels in acute HIV-1-infected patients are higher than those in HIV-negative subjects. IFN-lambdas R and IFN-alpha R mRNA levels are inversely correlated with CD4+ T-cell counts, but are positively correlated with viral loads.

CONCLUSIONS

The dynamic changes of IFNs related genes in JAK-STAT pathway in acute HIV-1 infection will deepen our understanding of the roles of IFN-lambdas in HIV pathogenesis.

Combination antiretroviral therapy (cART) restores HIV-1 infection-mediated impairment of JAK-STAT signaling pathway

JAK-STAT signaling pathway has a crucial role in host innate immunity against viral infections, including HIV-1. We therefore examined the impact of HIV-1 infection and combination antiretroviral therapy (cART) on JAK-STAT signaling pathway. Compared to age-matched healthy donors (n = 18), HIV-1-infected subjects (n = 18) prior to cART had significantly lower expression of toll-like receptors (TLR-1/4/6/7/8/9), the IFN regulatory factors (IRF-3/7/9), and the antiviral factors (OAS-1, MxA, A3G, PKR, and Tetherin). Three months’ cART partially restores the impaired functions of JAK-STAT-mediated antiviral immunity. We also found most factors had significantly positive correlations (p < 0.05) between each two factors in JAK-STAT pathway in healthy donors (98.25%, 168/171), but such significant positive associations were only found in small part of HIV-1-infected subjects (43.86%, 75/171), and stably increased during the cART (57.31%, 98/171 after 6 months’ cART). With regard to the restoration of some HIV-1 restriction factors, HIV-1-infected subjects who had CD4+ T cell counts > 350//μl responded better to cART than those with the counts < 350/μl. These findings indicate that the impairment of JAK-STAT pathway may play a role in the immunopathogenesis of HIV-1 disease.

IL28B genetic variation and cytomegalovirus-specific T-cell immunity in allogeneic stem cell transplant recipients

A single nucleotide polymorphism (SNP), 3 kbp upstream of the IL28B gene (rs12979860; C/T), has been shown to influence the dynamics of cytomegalovirus (CMV) replication in allogeneic stem cell transplant recipients (Allo-SCT). We investigated whether this SNP had any effect on the dynamics of CMV-specific T-cell immunity in these patients. CMV pp65/IE-1 IFN-γ CD8+ and CD4+ T cells were enumerated by flow cytometry in 85 patients with no prior CMV DNAemia (group A) and in 57 after the onset of CMV DNAemia (group B). Donor IL28B genotype was determined by real-time PCR and plasma levels of IL-28B were quantitated by ELISA. CMV-specific T-cell counts and plasma IL-28B levels in patients in group A were not significantly different among the IL28B genotype groups. Patients harboring the donor IL28B T/T genotype appeared to expand CMV-specific IFN-γ CD8+ cells to a higher level in response to viral replication than their C/T and C/C counterparts. Fewer patients in the T/T group received pre-emptive antiviral therapy (P = 0.05). Overall, a significant inverse correlation was observed between median IL-28B levels measured prior to the CMV DNAemia onset and the level of CMV-specific CD8+ T cells enumerated after detection of CMV DNAemia (σ = -0.471; P = 0.013). In summary, the data suggested that the protective effect attributed to the rs12979860 SNP minor T allele could be mediated, at least in part, by eliciting robust CMV-specific T-cell responses. J. Med. Virol. 89:685-695, 2017. © 2016 Wiley Periodicals, Inc.

IFN-λ Inhibits Drug-Resistant HIV Infection of Macrophages

Type III interferons (IFN-λs) have been demonstrated to inhibit a number of viruses, including HIV. Here, we further examined the anti-HIV effect of IFN-λs in macrophages. We found that IFN-λs synergistically enhanced anti-HIV activity of antiretrovirals [azidothymidine (AZT), efavirenz, indinavir, and enfuvirtide] in infected macrophages. Importantly, IFN-λs could suppress HIV infection of macrophages with the drug-resistant strains, including AZT-resistant virus (A012) and reverse transcriptase inhibitor-resistant virus (TC49). Mechanistically, IFN-λs were able to induce the expression of several important anti-HIV cellular factors, including myxovirus resistance 2 (Mx2), a newly identified HIV post-entry inhibitor and tetherin, a restriction factor that blocks HIV release from infected cells. These observations provide additional evidence to support the potential use of IFN-λs as therapeutics agents for the treatment of HIV infection.

Interferon Lambda: Modulating Immunity in Infectious Diseases

Interferon lambdas (IFN-λs; IFNL1-4) modulate immunity in the context of infections and autoimmune diseases, through a network of induced genes. IFN-λs act by binding to the heterodimeric IFN-λ receptor (IFNLR), activating a STAT phosphorylation-dependent signaling cascade. Thereby hundreds of IFN-stimulated genes are induced, which modulate various immune functions via complex forward and feedback loops. When compared to the well-characterized IFN-α signaling cascade, three important differences have been discovered. First, the IFNLR is not ubiquitously expressed: in particular, immune cells show significant variation in the expression levels of and susceptibilities to IFN-λs. Second, the binding affinities of individual IFN-λs to the IFNLR varies greatly and are generally lower compared to the binding affinities of IFN-α to its receptor. Finally, genetic variation in the form of a series of single-nucleotide polymorphisms (SNPs) linked to genes involved in the IFN-λ signaling cascade has been described and associated with the clinical course and treatment outcomes of hepatitis B and C virus infection. The clinical impact of IFN-λ signaling and the SNP variations may, however, reach far beyond viral hepatitis. Recent publications show important roles for IFN-λs in a broad range of viral infections such as human T-cell leukemia type-1 virus, rotaviruses, and influenza virus. IFN-λ also potentially modulates the course of bacterial colonization and infections as shown for Staphylococcus aureus and Mycobacterium tuberculosis. Although the immunological processes involved in controlling viral and bacterial infections are distinct, IFN-λs may interfere at various levels: as an innate immune cytokine with direct antiviral effects; or as a modulator of IFN-α-induced signaling via the suppressor of cytokine signaling 1 and the ubiquitin-specific peptidase 18 inhibitory feedback loops. In addition, the modulation of adaptive immune functions via macrophage and dendritic cell polarization, and subsequent priming, activation, and proliferation of pathogen-specific T- and B-cells may also be important elements associated with infectious disease outcomes. This review summarizes the emerging details of the IFN-λ immunobiology in the context of the host immune response and viral and bacterial infections.

Elevated Serum Levels of Interleukin-29 Are Associated with Disease Activity in Rheumatoid Arthritis Patients with Anti-Cyclic Citrullinated Peptide Antibodies

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease that may lead to progressive joint destruction. The anti-cyclic citrullinated peptide (anti-CCP) antibody is an essential marker for the diagnosis of RA and has a crucial role in the bone destruction in RA. Recent studies have shown that interleukin (IL)-29, a vital member of type III interferon (IFN) family, could enhance proinflammatory cytokine production and might be involved in the joint destruction in RA. Therefore, in this study, we aimed to examine the role of IL-29 in RA patients with anti-CCP antibodies. The result showed that the serum IL-29 levels were higher in RA patients (n = 68) compared with healthy controls (HC, n = 68, P = 0.019). Correlation analysis demonstrated a significant positive correlation among serum IL-29 level, rheumatoid factor (RF, P < 0.001) and anti-CCP antibodies (P = 0.042). However, when RA patients were divided into two groups according to anti-CCP antibodies, the serum IL-29 levels were significantly higher in anti-CCP-antibodies positive RA patients (n = 54) than those in HC (n = 68) and anti-CCP-antibodies negative RA patients (n = 14). Furthermore, the serum IL-29 levels were positively correlated with the disease activity (P < 0.05) and significantly declined after 6 months of treatment (P < 0.01) in the anti-CCP-antibodies positive RA patients, whereas no significant change was found in the anti-CCP-antibodies negative RA patients (P > 0.05). The findings indicate that IL-29 is a potential biomarker for disease activity in anti-CCP-antibodies positive RA patients.

Antiviral factors and type I/III interferon expression associated with regulatory factors in the oral epithelial cells from HIV-1-serodiscordant couples

Individuals who remain HIV-seronegative despite repeated unprotected exposure to the virus are defined as exposed seronegative (ESN) individuals. Innate and adaptive immunity, as well as genetic factors, provide ESNs with important advantages that allow for low infection susceptibility. The majority of HIV-1-infected individuals undergo antiretroviral therapy, which can decrease the level of HIV-1 exposure in ESNs. We analyzed type I interferon (IFN)-related antiviral and regulatory factors in peripheral blood mononuclear cells (PBMCs) and oral epithelial cells from serodiscordant couples. Our findings revealed that ESNs did not induce the expression of antiviral factors (APOBEC-3G, TRIM5-α, SAMDH1, STING, TBk1) or regulatory factors (Trex, Foxo3, Socs3, IL-10) in PBMCs, unlike their HIV-1-infected partners. In contrast, ESNs upregulated APOBEC-3G and type I/III IFNs (IFNs-α,-β/-λ) in oral mucosal epithelial cells similar to their HIV-infected partners. The serodiscordant groups exhibited an increased expression of type I IFN-induced regulators, such as Trex and Foxo3, in oral epithelial cells. TLR7, TLR8 and TLR9 were expressed in oral epithelial cells of both ESNs and HIV-1-infected subjects. These findings revealed evidence of antiviral factors, type I/III interferon and regulatory factor expression only in the oral mucosal compartment of ESNs, while HIV-1-infected partners systemically and oral mucosal expressed the antiviral profile.

Monoclonal Antibody to Bone Marrow Stromal Cell Antigen 2 Protein of Swine

The bone marrow stromal cell antigen 2 (BST-2) protein was identified as a novel virus restriction factor that potently restricts the replication and egress of enveloped viruses. In this study, we generated monoclonal antibodies (MAbs) against porcine BST-2 encoding 34-112 aa of porcine BST-2, which was cloned and inserted into the prokaryotic expression vector pCold-I to construct a recombinant plasmid pCold-pBST-2. The recombinant porcine BST-2 protein (rpBST-2 protein) was induced by isopropyl-β-D-thiogalactoside in Escherichia coli BL21 (DE3). Then, BALB/c mice were immunized with the purified rpBST-2 protein to prepare MAbs of BST-2. After subcloning, one strain of hybridoma cells named 1B2 secreting porcine BST-2 protein monoclonal antibody (MAb) was obtained. Indirect immunofluorescence assay and western blot analysis showed that the MAb was specifically reacted with the overexpressed porcine BST-2 protein in Vero cells. The specific MAb of porcine BST-2 provides a valuable tool for further studies of BST-2 to restrict virus infection.

Parainfluenza Virus 3 Blocks Antiviral Mediators Downstream of the Interferon Lambda Receptor by Modulating Stat1 Phosphorylation

Parainfluenza viruses are known to inhibit type I interferon (IFN) production; however, there is a lack of information regarding the type III IFN response during infection. Type III IFNs signal through a unique heterodimeric receptor, IFN-λR1/interleukin-10R2 (IL-10R2), which is primarily expressed by epithelial cells. Parainfluenza virus 3 (PIV-3) infection is highly restricted to the airway epithelium. We therefore sought to examine type III IFN signaling pathways during PIV-3 infection of epithelial cells. We used three strains of PIV-3: human PIV-3 (HPIV-3), bovine PIV-3 (BPIV-3), and dolphin PIV-1 (Tursiops truncatus PIV-1, or TtPIV-1). Here, we show that message levels of IL-29 are significantly increased during PIV-3 infection, yet downstream antiviral signaling molecules are not upregulated to levels similar to those of the positive control. Furthermore, in Vero cells infected with PIV-3, stimulation with recombinant IL-29/-28A/-28B does not cause upregulation of downstream antiviral molecules, suggesting that PIV-3 interferes with the JAK/STAT pathway downstream of the IFN-λR1/IL-10R2 receptor. We used Western blotting to examine the phosphorylation of Stat1 and Stat2 in Vero cells and the bronchial epithelial cell line BEAS-2B. In Vero cells, we observed reduced phosphorylation of the serine 727 (S727) site on Stat1, while in BEAS-2B cells Stat1 phosphorylation was decreased at the tyrosine 701 (Y701) site during PIV-3 infection. PIV-3 therefore interferes with the phosphorylation of Stat1 downstream of the type III IFN receptor. These data provide new evidence regarding strategies employed by parainfluenza viruses to effectively circumvent respiratory epithelial cell-specific antiviral immunity.

IMPORTANCE

Parainfluenza virus (PIV) in humans is associated with bronchiolitis and pneumonia and can be especially problematic in infants and the elderly. Also seen in cattle, bovine PIV-3 causes respiratory infections in young calves. In addition, PIV-3 is one of a number of pathogens that contribute to the bovine respiratory disease complex (BRDC). As their name suggests, interferons (IFNs) are produced by cells to interfere with viral replication. Paramyxoviruses have previously been shown to block production and downstream signaling of type I IFNs. For the first time, it is shown here that PIV-3 can induce protective type III IFNs in epithelial cells, the primary site of PIV-3 infection. However, we found that PIV-3 modulates signaling pathways downstream of the type III IFN receptor to block production of several specific molecules that aid in a productive antiviral response. Importantly, this work expands our understanding of how PIV-3 effectively evades host innate immunity.

IFN-λ is able to augment TLR-mediated activation and subsequent function of primary human B cells

During the past decade, increased emphasis has been placed on finding alternatives to IFN-α-based therapies. One such alternative, IFN-λ, has shown therapeutic promise in a variety of diseases, but research of this family of cytokines has been primarily focused on their antiviral activities. The goal of the present study was to investigate the role of IFN-λ in the regulation and modulation of B cell function. We show that, similar to IFN-α, IFN-λ1 is able to augment TLR-mediated B cell activation, partially attributed to an upregulation of TLR7 expression, and that both naïve and memory B cells express the limiting type III IFN receptor component, IFN-λR1. Furthermore, this IFN-λ-enhanced B cell activation resulted in increased cytokine and Ig production during TLR7 challenge, most prominently after the addition of helper T cell signals. Ultimately, these elevated cytokine and Ig levels could be partially attributed to the increase in proliferation of TLR7-challenged B cells by both type I and type III IFNs. These findings demonstrate the ability of IFN-λ to boost humoral immunity, an important attribute to consider for further studies on immunity to pathogens, vaccine development, and ongoing advancement of therapeutic strategies aimed at replacing IFN-α-based treatments with IFN-λ.

IFNL4 rs368234815 polymorphism is associated with innate resistance to HIV-1 infection

The interferon (IFN)L4 polymorphism rs368234815 is associated with hepatitis C virus (HCV) spontaneous clearance and response to IFN-based treatments. The role of this polymorphism in HIV-1 infection is controversial. We investigated whether genetic variation at IFNL4 is associated to HIV-1 acquisition. The HCV protective allele TT was associated with decreased likelihood of HIV-1 infection in male intravenous drug users [odds ratio (OR): 0.3; P = 0.006], and this association was not modified by the genotype of CCR5. These results suggest that genetic susceptibility to HCV and HIV-1 infection shares common molecular pathways.

Identification of a JAK/STAT pathway receptor domeless from Pacific white shrimp Litopenaeus vannamei

The Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling pathway was known to participate in dozens of immune responses in organisms. Domeless, first identified in Drosophila melanogaster, is a unique receptor involved in invertebrate JAK/STAT pathway. In this study, a cytokine receptor (LvDOME) was identified in Litopenaeus vannamei. The LvDOME cDNA was 5178bp in length with an Open Reading Frame (ORF) of 4191bp. LvDOME contained two cytokine binding modules (CBMs) and three fibronectin-type-III-like (FNIII) domains, similar to most vertebrate IL-6 receptors. LvDOME was expressed highest in shrimp muscle and could be up-regulated in the late stage of white spot syndrome virus (WSSV) infection. LvDOME could significantly enhance the activity of the WSSV wsv069 gene promoter through acting on the STAT-binding motif, suggesting LvDOME could activate the JAK/STAT pathway. Moreover, knockdown of LvDOME resulted in lower cumulative mortality of shrimps and less WSSV copies, suggesting LvDOME may be hijacked by WSSV to benefit virus replication. To our knowledge, this is the first report on the receptor of JAK/STAT pathway in shrimp.

Promotion of expression of interferon-stimulated genes in U937 monocytic cells by HIV RNAs, measured using stable isotope labeling with amino acids in cell culture (SILAC)

Type I interferon (IFN) exerts strong antiviral activity, particularly against human immunodeficiency virus (HIV), and although several viral proteins have been shown to deregulate IFN induction, little is known about the induction of type I IFNs by HIV RNAs. In the present study, we used the stable isotope labeling with amino acids in cell culture (SILAC) method to determine the proteomic profile in U937 monocytic cells after transfection with viral RNA of HIV. We then used a western blot assay to validate the proteomic results. It was revealed by the SILAC method that there were 1624 non-redundant peptides with quantitative information and 281 proteins with quantitative information in the HIV-RNA-transfected U937 cells when compared to cells transfected with control RNA. In particular, 6, 8 or 12 hours post-transfection, HIV RNA transfection promoted the expression of such interferon stimulated genes (ISGs) as interferon-induced proteins with tetratricopeptide repeats (IFITs), interferon-induced transmembrane proteins (IFITMs), interferon-induced gene 15 protein (ISG15), myxovirus (influenza virus) resistance protein 1 (MX1), and interferon-induced guanylate-binding protein 1 (GBP1), and this was confirmed by western blot assay. In conclusion, HIV RNA is a strong stimulator of IFNs, promoting the expression of such ISGs as IFITs, IFITMs, ISG15, MX1 and GBP1.

Comparison of antiviral activity of lambda-interferons against HIV replication in macrophages

Lambda-interferons (IFN-λs) have been demonstrated as having the ability to inhibit HIV replication in macrophages. However, specific differences in signaling transduction and anti-HIV activity in macrophages between different IFN-λs are unclear. Here, we showed that although all 3 members of (IFN-λ1, λ2, and λ3) IFN-λ family induced the expression of a number of genes of janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling pathway in monocyte-derived macrophages, IFN-λ1 or IFN-λ3 induced higher levels of antiviral IFN-stimulated genes (ISGs) expression than did IFN-λ2. In addition, IFN-λ1 or IFN-λ3 induced higher levels of several pattern recognition receptors (PPRs) than did IFN-λ2. Incubation of IFN-λs with HIV-infected macrophages showed that IFN-λ1 or IFN-λ3 is more potent in anti-HIV activity than IFN-λ2. We also showed that IFN-λ treatment before HIV infection was more potent in HIV inhibition than that after HIV infection. Further investigations showed that the inductions of ISGs and PPRs expression by IFN-λs were largely compromised by HIV infection. These findings provide further experimental evidence that IFN-λs have therapeutic potential in treatment of HIV infection.

Impact and regulation of lambda interferon response in human metapneumovirus infection

Human metapneumovirus (hMPV) is a respiratory paramyxovirus that is distributed worldwide and induces significant airway morbidity. Despite the relevance of hMPV as a pathogen, many aspects of the immune response to this virus are still largely unknown. In this report, we focus on the antiviral immune response, which is critical for viral clearance and disease resolution. Using in vitro and in vivo systems, we show that hMPV is able to induce expression of lambda interferon 1 (IFN-λ1), IFN-λ2, IFN-λ3, and IFN-λ4. The induction of IFN-λ expression by hMPV was dependent on interferon regulatory factor 7 (IRF-7) expression but not on IRF-3 expression. Treatment of hMPV-infected mice with IFN-λ reduced the disease severity, lung viral titer, and inflammatory response in the lung. Moreover, the IFN-λ response induced by the virus was regulated by the expression of the hMPV G protein. These results show that type III interferons (IFN-λs) play a critical protective role in hMPV infection.

IMPORTANCE

Human metapneumovirus (hMPV) is a pathogen of worldwide importance. Despite the relevance of hMPV as a pathogen, critical aspects of the immune response induced by this virus remain unidentified. Interferons (IFNs), including IFN-λ, the newest addition to the interferon family, constitute an indispensable part of the innate immune response. Here, we demonstrated that IFN-λ exhibited a protective role in hMPV infection in vitro and in an experimental mouse model of infection.

Hepatitis B virus coinfection in human immunodeficiency virus-infected patients: A review

Hepatitis B virus (HBV) infection is a leading cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma worldwide. Due to the shared modes of transmission, coinfection with HBV and human immunodeficiency virus (HIV) is not uncommon. It is estimated that 10% of HIV-infected patients worldwide are coinfected with HBV. In areas where an HBV vaccination program is implemented, the HBV seroprevalence has declined significantly. In HIV/HBV-coinfected patients, HBV coinfection accelerates immunologic and clinical progression of HIV infection and increases the risk of hepatotoxicity when combination antiretroviral therapy (cART) is initiated, while HIV infection increases the risk of hepatitis events, cirrhosis, and end-stage liver disease related to chronic HBV infection. With the advances in antiviral therapy, concurrent, successful long-term suppression of HIV and HBV replication can be achieved in the cART era. To reduce the disease burden of HBV infection among HIV-infected patients, adoption of safe sex practices, avoidance of sharing needles and diluent, HBV vaccination and use of cART containing tenofovir disoproxil fumarate plus emtricitabine or lamivudine are the most effective approaches. However, due to HIV-related immunosuppression, using increased doses of HBV vaccine and novel approaches to HBV vaccination are needed to improve the immunogenicity of HBV vaccine among HIV-infected patients.

Toll-like receptor 3 signaling inhibits simian immunodeficiency virus replication in macrophages from rhesus macaques

Toll-like receptor 3 (TLR3) recognizes double-stranded RNA and induces multiple intracellular events responsible for innate antiviral immunity against viral infections. Here we demonstrate that TLR3 signaling of monocyte-derived macrophages (MDM) from rhesus monkeys by poly I:C inhibited simian immunodeficiency virus (SIV) infection and replication. Investigation of the mechanisms showed that TLR3 activation resulted in the induction of type I and type III interferons (IFNs) and IFN-inducible antiviral factors, including APOBEC3G (A3G), tetherin and SAMHD1. In addition, poly I:C-treated macaque macrophages expressed increased levels of CC chemokines including CCL3, CCL4 and CCL5, the ligands for HIV or SIV coreceptor CCR5. Furthermore, TLR3 signaling of macaque macrophages induced the expression of cellular microRNAs (miR-29a, -29b, -146a and -9), the newly identified intracellular SIV restriction factors. TLR3 activation-mediated anti-SIV effect could be compromised by the knockdown of IRF3 and IRF7. These findings indicate that TLR3-mediated induction of multiple viral restriction factors contribute to the inhibition of SIV infection in macaque macrophages, which support future preclinical studies using rhesus macaques to determine whether in vivo TLR3 activation is safe and beneficial for treating people infected with HIV.

Interferons: Success in anti-viral immunotherapy

The interferons (IFNs) are glycoproteins with strong antiviral activities that represent one of the first lines of host defense against invading pathogens. These proteins are classified into three groups, Type I, II and III IFNs, based on the structure of their receptors on the cell surface. Due to their ability to modulate immune responses, they have become attractive therapeutic options to control chronic virus infections. In combination with other drugs, Type I IFNs are considered as "standard of care" in suppressing Hepatitis C (HCV) and Hepatitis B (HBV) infections, while Type III IFN has generated encouraging results as a treatment for HCV infection in phase III clinical trials. However, though effective, using IFNs as a treatment is not without the need for caution. IFNs are such powerful cytokines that affect a wide array of cell types; as a result, patients usually experience unpleasant symptoms, with a percentage of patients suffering system wide effects. Thus, constant monitoring is required for patients treated with IFN in order to reach the treatment goals of suppressing virus infection and maintaining quality of life.

Validation of TaqMan® SNP genotyping specificity for rs12979860 of IL-28B: modeling primer specificity in vitro

Members of the type III interferon gene family arose by gene duplication events and have retained a high percent identity both in their coding and non-coding regions. In this study, the specificity of a widely used TaqMan(®) SNP genotyping assay for rs12979860 is validated. The 66 bp template for SNP genotyping has only 3 bp at one 5' end that vary between IL-28B and IL-28A; excluding the rs12979860 SNP itself. Conflicting annealing temperatures were found for the mismatched 19 bp primer to IL-28B and IL-28A with in silico melting temperature algorithms, or with in vitro dissociation curves. In order to prove specificity for IL-28B, an in vitro competition assay was setup with genomic DNA and synthetic oligonucleotides. When genomic DNA, containing equimolar concentrations of rs12979860 and the homologous region of IL-28A are present, no off-target amplification was observed. This SNP genotyping assay is therefore specific for rs12979860 and all previously reported results are valid. Finally, using a completely synthetic in vitro competition assay it was possible to calculate the amount of off-target template that will produce 1/2 the maximum on-target (VIC) fluorescent signal, a value that is between a C/C genotype and a T/T genotype. This value is defined in the manuscript as the half maximum positive value, KHPV, and in the present assay KHPV is 15.75±0.0721, represented as the relative fold increase in the amount of IL-28A over rs12979860. This method will be of interest to those performing genotyping on highly conserved gene families.

Innate and adaptive immune responses in male and female reproductive tracts in homeostasis and following HIV infection

The male and female reproductive tracts are complex microenvironments that have diverse functional demands. The immune system in the reproductive tract has the demanding task of providing a protective environment for a fetal allograft while simultaneously conferring protection against potential pathogens. As such, it has evolved a unique set of adaptations, primarily under the influence of sex hormones, which make it distinct from other mucosal sites. Here, we discuss the various components of the immune system that are present in both the male and female reproductive tracts, including innate soluble factors and cells and humoral and cell-mediated adaptive immunity under homeostatic conditions. We review the evidence showing unique phenotypic and functional characteristics of immune cells and responses in the male and female reproductive tracts that exhibit compartmentalization from systemic immunity and discuss how these features are influenced by sex hormones. We also examine the interactions among the reproductive tract, sex hormones and immune responses following HIV-1 infection. An improved understanding of the unique characteristics of the male and female reproductive tracts will provide insights into improving clinical treatments of the immunological causes of infertility and the design of prophylactic interventions for the prevention of sexually transmitted infections.

Counteraction of the multifunctional restriction factor tetherin

The interferon-inducible restriction factor tetherin (also known as CD317, BST-2 or HM1.24) has emerged as a key component of the antiviral immune response. Initially, tetherin was shown to restrict replication of various enveloped viruses by inhibiting the release of budding virions from infected cells. More recently, it has become clear that tetherin also acts as a pattern recognition receptor inducing NF-κB-dependent proinflammatory gene expression in virus infected cells. Whereas the ability to restrict virion release is highly conserved among mammalian tetherin orthologs and thus probably an ancient function of this protein, innate sensing seems to be an evolutionarily recent activity. The potent and broad antiviral activity of tetherin is reflected by the fact that many viruses evolved means to counteract this restriction factor. A continuous arms race with viruses has apparently driven the evolution of different isoforms of tetherin with different functional properties. Interestingly, tetherin has also been implicated in cellular processes that are unrelated to immunity, such as the organization of the apical actin network and membrane microdomains or stabilization of the Golgi apparatus. In this review, I summarize our current knowledge of the different functions of tetherin and describe the molecular strategies that viruses have evolved to antagonize or evade this multifunctional host restriction factor.