Severe West Nile virus and Sars-CoV-2 infections in a patient with thymoma and anti-type I IFN antibodies.

The current study aimed to investigate determinants of severity in a previously healthy patient who experienced two life-threatening infections, from West Nile Virus and SARS-CoV2. During COVID19 hospitalization he was diagnosed with a thymoma, retrospectively identified as already present at the time of WNV infection. Heterozygosity for p.Pro554Ser in the TLR3 gene, which increases susceptibility to severe COVID-19, and homozygosity for CCR5 c.554_585del, associated to severe WNV infection, were found. Neutralizing anti-IFN-α and anti-IFN-ω auto-antibodies were detected, likely induced by the underlying thymoma and increasing susceptibility to both severe COVID-19 pneumonia and West Nile encephalitis.

Expression of ISG60 is induced by TLR3 signaling in BEAS­2B bronchial epithelial cells: Possible involvement in CXCL10 expression.

Viral infections in the respiratory tract are common, and, in recent years, severe acute respiratory syndrome coronavirus 2 outbreaks have highlighted the effect of viral infections on antiviral innate immune and inflammatory reactions. Specific treatments for numerous viral respiratory infections have not yet been established and they are mainly treated symptomatically. Therefore, understanding the details of the innate immune system underlying the airway epithelium is crucial for the development of new therapies. The present study aimed to investigate the function and expression of interferon (IFN)­stimulated gene (ISG)60 in non­cancerous bronchial epithelial BEAS­2B cells exposed to a Toll­like receptor 3 agonist. BEAS­2B cells were treated with a synthetic TLR3 ligand, polyinosinic­polycytidylic acid (poly IC). The mRNA and protein expression levels of ISG60 were analyzed using reverse transcription­quantitative PCR and western blotting, respectively. The levels of C­X­C motif chemokine ligand 10 (CXCL10) were examined using an enzyme­linked immunosorbent assay, and the effects of knockdown of IFN­ß, ISG60 and ISG56 were examined using specific small interfering RNAs. Notably, ISG60 expression was increased in proportion to poly IC concentration, and recombinant human IFN­ß also induced ISG60 expression. By contrast, knockdown of IFN­ß and ISG56 decreased ISG60 expression, and ISG60 knockdown reduced CXCL10 and ISG56 expression. These findings suggested that ISG60 is partly implicated in CXCL10 expression and that ISG60 may serve a role in the innate immune response of bronchial epithelial cells. The present study highlights ISG60 as a potential target for new therapeutic strategies against viral infections in the airway.

TLR3, TLR7, and TLR8 genes expression datasets in COVID-19 patients: Influences of the disease severity and gender.

The prognosis of COVID-19 could influence by innate immune sensors such as toll-like receptors (TLRs). The purpose of this data was to investigate TLR3, 7, and 8 expression levels in COVID-19 patients and their relationship to outcome of disease. 75 confirm COVID-19 were included sequentially and separated into three groups: mild, severe, and critical. Peripheral blood mononuclear cells were isolated from the whole blood, and RNA was then extracted. The qRT-PCR technique was used to examine the expression of TLR3, TLR7, and TLR8 genes. The patients average ages were 52.69 ± 1.9 and 13 of the 25 individuals in each group were male. TLR3 (p < 0.001), TLR7 (p < 0.001), and TLR8 (p < 0.001) expression levels were considerably greater in COVID-19 patients compared to the control group. The findings also showed that individuals with critical and severe COVID-19 disease had significantly greater TLR7 and TLR8 gene expression levels than patients in mild stage of disease (p < 0.05). The data showed a significant difference (p = 0.01) in the TLR3 transcript levels between critical and mild COVID-19 patients. Furthermore, male severe (p = 0.02) and critical (p = 0.008) patients had significantly higher TLR8 expression levels than female patients in terms of gender. TLR3 (p = 0.2) and TLR7 (p = 0.08) transcripts were more elevated in males than females, but not significantly.

Retinoic Acid Neutralizes the Effects of Herpes Simplex Virus Type 1-Infected Cell Protein 0 (ICP0) in Retinal Pigment Epithelial Cells.

BACKGROUND: Herpes simplex virus (HSV) infection of the cornea, uvea, and retina is the leading infectious cause of blindness worldwide. This study examined the effects of retinoic acid (RA) on the protein levels of interleukin (IL)-17A and IL-23 cytokines with known proinflammatory effects and toll-like receptor 3 (TLR3) messenger RNA (mRNA) expression in retinal pigment epithelial (ARPE-19) cells treated with HSV-1-infected cell protein 0 (ICP0). METHODOLOGY: We used 3-[4.5-dimethylthiazol-2-yl]-2.5-diphenyl tetrazolium bromide assay to calculate the half maximal inhibitory concentration (IC50) doses of RA and ICP0 in ARPE-19 cells. At the end of 24 hours, protein levels of IL-17A and IL-23 were analyzed using enzyme-linked immunosorbent assay. TLR3 mRNA expression levels were also calculated using reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: RA administration decreased IL-17A levels, which were elevated by ICP0. The IL-23 levels were similar between the ICP0-treated and control groups, but the difference was significant between the ICP0-treated group and RA+ICP0 combination. These results showed that RA can significantly increase IL-23 levels in the presence of ICP0. Although ICP0 dramatically increased TLR3 mRNA expression compared with that in the control group, the RA+ICP0 combination returned TLR3 mRNA expression to a level similar to that in the control group (P = 0.419). CONCLUSIONS: RA may potentially neutralize HSV-1 ICP0 negative effects in ARPE-19 cells.

Genetic variation of TLR3 gene is associated with the outcome of hepatitis b infection in mauritanian patients: case control study.

BACKGROUND: Toll-Like receptors (TLRs) play an important role in the immune response during hepatitis B virus (HBV) infection. In this study, we evaluated the association between two SNP variants (TLR3 rs3775290 and TLR4 rs4986790) and susceptibility to chronic HBV infection in Mauritania. SUBJECTS AND METHODS: A total of 188 subjects were recruited for this study: 102 chronically infected patients and 86 individuals with spontaneously resolved HBV infection who were considered controls. Targeted PCR products were sequenced using Sanger sequencing. RESULTS: We found that TLR3 rs3775290 was significantly more frequent in patients with chronic HBV than in the control population (p = 0.03). However, no association was found between the TLR4 rs3775290 polymorphism and chronic infection. CONCLUSION: Our results suggest that the TLR3 rs3775290 polymorphism may be a risk factor for susceptibility to chronic HBV infection in the Mauritanian population.

Aluminum oxyhydroxide-Poly(I:C) combination adjuvant with balanced immunostimulatory potentials for prophylactic vaccines.

The development of high-purity antigens promotes the urgent need of novel adjuvant with the capability to trigger high levels of immune response. Polyinosinic-polycytidylic (Poly(I:C)) is a synthetic double-stranded RNA (dsRNA) that can engage Toll-like receptor 3 (TLR3) to initiate immune responses. However, the Poly(I:C)-induced toxicity and inefficient delivery prevent its applications. In our study, combination adjuvants are formulated by aluminum oxyhydroxide nanorods (AlOOH NRs) and Poly(I:C), named Al-Poly(I:C), and the covalent interaction between the two components is further demonstrated. Al-Poly(I:C) mediates enhanced humoral and cellular immune responses in three antigen models, i.e., HBsAg virus-like particles (VLPs), human papilloma virus (HPV) VLPs and varicella-zoster virus (VZV) glycoprotein E (gE). Further mechanistic studies demonstrate that the dose and molecular weight (MW) of Poly(I:C) determine the physicochemical properties and adjuvanticity of the Al-Poly(I:C) combination adjuvants. Al-Poly(I:C) with higher Poly(I:C) dose promotes antigen-bearing dendritic cells (DCs) recruitment and B cells proliferation in lymph nodes. Al-Poly(I:C) formulated with higher MW Poly(I:C) induces higher activation of helper T cells, B cells, and CTLs. This study demonstrates that Al-Poly(I:C) potentiates the humoral and cellular responses in vaccine formulations. It offers insights for adjuvant design to meet the formulation requirements in both prophylactic and therapeutic vaccines.

Specific binding sites on Rhesus rotavirus capsid protein dictates the method of endocytosis inducing the murine model of biliary atresia.

Biliary atresia (BA) is the leading indication for pediatric liver transplantation. Rhesus rotavirus (RRV) induced murine BA develops an obstructive cholangiopathy that mirrors the human disease. We have previously demonstrated the "SRL" motif on RRV's VP4 protein binds to heat shock cognate 70 protein (Hsc70) facilitating entry into cholangiocytes. In this study, we analyzed how binding to Hsc70 affects viral endocytosis, intracellular trafficking, and uniquely activates the signaling pathway that induces murine BA. Inhibition of clathrin- and dynamin-mediated endocytosis in cholangiocytes following infection demonstrated blocking dynamin decreased the infectivity of RRV whereas clathrin inhibition had no effect. Blocking early endosome trafficking resulted in decreased viral titers of RRV while late endosome inhibition had no effect. Following infection, TLR3 expression and p-NF-κB levels increased in cholangiocytes, leading to increased release of CXCL9 and CXCL10. Infected mice knocked out for TLR3 had decreased levels of CXCL9 and CXCL10, resulting in reduced NK cell numbers. Human BA patients experienced an increase in CXCL10 levels, suggesting this as a possible pathway leading to biliary obstruction. Viruses that utilize Hsc70 for cell entry exploit a clathrin-independent pathway and traffic to the early recycling endosome uniquely activating NF-κB through TLR3, leading to the release of CXCL9 and CXCL10, and inducing NK cell recruitment. These results define how the "SRL" peptide found on RRV's VP4 protein modulates viral trafficking, inducing the host response leading to bile duct obstruction.

TLR3 signaling-induced interferon-stimulated gene 56 plays a role in the pathogenesis of rheumatoid arthritis.

Rheumatoid fibroblast-like synoviocytes (RFLS) have an important role in the inflammatory pathogenesis of rheumatoid arthritis (RA). Toll-like receptor 3 (TLR3) is upregulated in RFLS; its activation leads to the production of interferon-ß (IFN-ß), a type I IFN. IFN-stimulated gene 56 (ISG56) is induced by IFN and is involved in innate immune responses; however, its role in RA remains unknown. Therefore, the purpose of this study was to investigate the role of TLR3-induced ISG56 in human RFLS. RFLS were treated with polyinosinic-polycytidylic acid (poly I:C), which served as a TLR3 ligand. ISG56, melanoma differentiation-associated gene 5 (MDA5), and C-X-C motif chemokine ligand 10 (CXCL10) expression were measured using quantitative reverse transcription-polymerase chain reaction, western blotting, and enzyme-linked immunosorbent assay. Using immunohistochemistry, we found that ISG56 was expressed in synovial tissues of patients with RA and osteoarthritis. Under poly I:C treatment, ISG56 was upregulated in RFLS. In addition, we found that the type I IFN-neutralizing antibody mixture suppressed ISG56 expression. ISG56 knockdown decreased CXCL10 expression and MDA5 knockdown decreased ISG56 expression. In addition, we found that ISG56 was strongly expressed in the synovial cells of patients with RA. TLR3 signaling induced ISG56 expression in RFLS and type I IFN was involved in ISG56 expression. ISG56 was also found to be associated with CXCL10 expression, suggesting that ISG56 may be involved in TLR3/type I IFN/CXCL10 axis, and play a role in RA synovial inflammation.

TLR3-mediated Astrocyte Responses in High and Normal Glucose Adaptation Differently Regulated by Metformin.

Toll-like receptors 3 (TLR3) are innate immune receptors expressed on a wide range of cell types, including glial cells. Inflammatory responses altered by hyperglycemia highlight the need to explore the molecular underpinnings of these changes in cellular models. Therefore, here we estimated TLR3-mediated response of astrocytes cultured at normal (NG, 5 mM) and high (HG, 22.5 mM) glucose concentrations for 48 h before stimulation with polyinosinic:polycytidylic acid Poly(I:C) (PIC) for 6 h. Seahorse Extracellular Flux Analyzer (Seahorse XFp) was used to estimate the extracellular acidification rate (ECAR) and oxygen consumption rate (OCR). Although adaptation to HG affected ECAR and OCR, the stimulation of cells with PIC had no effect on ECAR. PIC reduced maximal OCR, but this effect disappeared upon adaptation to HG. PIC-stimulated release of cytokines IL-1ß, IL-10 was reduced, and that of IL-6 and iNOS was increased in the HG model. Adaptation to HG reduced PIC-stimulated synthesis of COX-derived oxylipins measured by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Adaptation to HG did not alter PIC-stimulated p38 activity, ERK mitogen-activated protein kinase, STAT3 and ROS production. Metformin exhibited anti-inflammatory activity, reducing PIC-stimulated synthesis of cytokines and oxylipins. Cell adaptation to high glucose concentration altered the sensitivity of astrocytes to TLR3 receptor activation, and the hypoglycemic drug metformin may exert anti-inflammatory effects under these conditions.

TRIF-dependent signaling and its role in liver diseases.

TIR domain-containing adaptor inducing IFN-ß (TRIF) is a crucial adaptor molecule downstream of toll-like receptors 3 (TLR3) and 4 (TLR4). TRIF directly binds to TLR3 through its TIR domain, while it associates with TLR4 indirectly through the bridge adaptor molecule TRIF-related adaptor molecule (TRAM). TRIF plays a pivotal role in regulating interferon beta 1 (IFN-ß) response, nuclear factor kappa B (NF-κB) signaling, apoptosis, and necroptosis signaling mediated by TLR3 and TLR4. It accomplishes these by recruiting and activating various kinases or transcription factors via its distinct domains. In this review, we comprehensively summarize the TRIF-dependent signaling pathways mediated by TLR3 and TLR4, elucidating key target molecules and downstream pathways. Furthermore, we provide an overview of TRIF's impact on several liver disorders, including drug-induced liver injury, ischemia-reperfusion liver injury, autoimmune hepatitis, viral hepatitis, alcohol-associated liver disease (ALD), metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH). We also explore its effects on liver steatosis, inflammation, fibrosis, and carcinogenesis. A comprehensive understanding of the TRIF-dependent signaling pathways, as well as the intricate relationship between TRIF and liver diseases, can facilitate the identification of potential drug targets and the development of novel and effective therapeutics against hepatic disorders.

Oxymatrine Modulation of TLR3 Signaling: A Dual-Action Mechanism for H9N2 Avian Influenza Virus Defense and Immune Regulation.

In our research, we explored a natural substance called Oxymatrine, found in a traditional Chinese medicinal plant, to fight against a common bird flu virus known as H9N2. This virus not only affects birds but can also pose a threat to human health. We focused on how this natural compound can help in stopping the virus from spreading in cells that line the lungs of birds and potentially humans. Our findings show that Oxymatrine can both directly block the virus and boost the body's immune response against it. This dual-action mechanism is particularly interesting because it indicates that Oxymatrine might be a useful tool in developing new ways to prevent and treat this type of bird flu. Understanding how Oxymatrine works against the H9N2 virus could lead to safer and more natural ways to combat viral infections in animals and humans, contributing to the health and well-being of society. The H9N2 Avian Influenza Virus (AIV) is a persistent health threat because of its rapid mutation rate and the limited efficacy of vaccines, underscoring the urgent need for innovative therapies. This study investigated the H9N2 AIV antiviral properties of Oxymatrine (OMT), a compound derived from traditional Chinese medicine, particularly focusing on its interaction with pulmonary microvascular endothelial cells (PMVECs). Employing an array of in vitro assays, including 50% tissue culture infectious dose, Cell Counting Kit-8, reverse transcription-quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, and Western blot, we systematically elucidated the multifaceted effects of OMT. OMT dose-dependently inhibited critical antiviral proteins (PKR and Mx1) and modulated the expression of type I interferons and key cytokines (IFN-α, IFN-ß, IL-6, and TNF-α), thereby affecting TLR3 signaling and its downstream elements (NF-κB and IRF-3). OMT's antiviral efficacy extended beyond TLR3-mediated responses, suggesting its potential as a versatile antiviral agent. This study not only contributes to the growing body of research on the use of natural compounds as antiviral agents but also underscores the importance of further investigating the broader application of OMT for combating viral infections.

A RIPK1-specific PROTAC degrader achieves potent antitumor activity by enhancing immunogenic cell death.

Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) functions as a critical stress sentinel that coordinates cell survival, inflammation, and immunogenic cell death (ICD). Although the catalytic function of RIPK1 is required to trigger cell death, its non-catalytic scaffold function mediates strong pro-survival signaling. Accordingly, cancer cells can hijack RIPK1 to block necroptosis and evade immune detection. We generated a small-molecule proteolysis-targeting chimera (PROTAC) that selectively degraded human and murine RIPK1. PROTAC-mediated depletion of RIPK1 deregulated TNFR1 and TLR3/4 signaling hubs, accentuating the output of NF-κB, MAPK, and IFN signaling. Additionally, RIPK1 degradation simultaneously promoted RIPK3 activation and necroptosis induction. We further demonstrated that RIPK1 degradation enhanced the immunostimulatory effects of radio- and immunotherapy by sensitizing cancer cells to treatment-induced TNF and interferons. This promoted ICD, antitumor immunity, and durable treatment responses. Consequently, targeting RIPK1 by PROTACs emerges as a promising approach to overcome radio- or immunotherapy resistance and enhance anticancer therapies.

Adolescent intermittent ethanol (AIE) sensitized fever in male Sprague Dawley rats exposed to poly I:C in adulthood.

Fever plays an indispensable role in host defense processes and is used as a rapid index of infection severity. Unfortunately, there are also substantial individual differences in fever reactions with biological sex, immunological history, and other demographic variables contributing to adverse outcomes of infection. The present series of studies were designed to test the hypothesis that a history of adolescent alcohol misuse may be a latent experiential variable that determines fever severity using polyinosinic:polycytidylic acid (poly I:C), a synthetic form of double-stranded RNA that mimics a viral challenge. Adult male and female Sprague Dawley rats were injected with 0 (saline) or 4 mg/kg poly I:C to first establish sex differences in fever sensitivity in Experiment 1 using implanted radiotelemetry devices for remote tracking. In Experiments 2 and 3, adolescent males and females were exposed to either water or ethanol (0 or 4 g/kg intragastrically, 3 days on, 2 days off, ∼P30-P50, 4 cycles/12 exposures total). After a period of abstinence, adult rats (∼P80-96) were then challenged with saline or poly I:C, and fever induction and maintenance were examined across a prolonged time course of 8 h using implanted probes. In Experiments 4 and 5, adult male and female subjects with a prior history of adolescent water or adolescent intermittent ethanol (AIE) were given saline or poly I:C, with tissue collected for protein and gene expression analysis at 5 h post-injection. Initial sex differences in fever sensitivity were minimal in response to the 4 mg/kg dose of poly I:C in ethanol-naïve rats. AIE exposed males injected with poly I:C showed a sensitized fever response as well as enhanced TLR3, IκBα, and IL-1ß expression in the nucleus of the solitary tract. Other brain regions related to thermoregulation and peripheral organs such as spleen, liver, and blood showed generalized immune responses to poly I:C, with no differences evident between AIE and water-exposed males. In contrast, AIE did not affect responsiveness to poly I:C in females. Thus, the present findings suggest that adolescent binge drinking may produce sex-specific and long-lasting effects on fever reactivity to viral infection, with preliminary evidence suggesting that these effects may be due to centrally-mediated changes in fever regulation rather than peripheral immunological mechanisms.

Immunogenic cell death mediated TLR3/4-activated MSCs in U87 GBM cell line.

Background and aims: Glioblastoma (GBM) is an aggressive primary brain cancer with no promising curative therapies. It has been indicated that MSCs can interact with the tumour microenvironment (TME) through the secretion of soluble mediators regulating intercellular signalling within the TME. TLRs are a multigene family of pattern recognition receptors with evolutionarily conserved regions and are widely expressed in immune and other body cells. MSCs by TLRs can recognize conserved molecular components (DAPMPs and PAPMPs) and activate signalling pathways, which regulate immune and inflammatory responses. MSCs may exert immunomodulatory functions through interaction with their expressed toll-like receptors (TLRs) and exert a protective effect against tumour antigens. As an emerging approach, we aimed to monitor the U87 cell line growth, migration and death markers following specific TLR3/4-primed-MSCs-CMs treatment. Methods and results: We investigated the phenotypic and functional outcomes of primed-CMs and glioma cell line co-culture following short-term, low-dose TLR3/4 priming. The gene expression profile of target genes, including apoptotic markers and related genes, was analyzed by qRT-PCR. MicroRNA-Seq examined the miRNA expression patterns, and flow cytometry evaluated the cell viability and cycle stages. The results showed significant changes in apoptosis and likely necroptosis-related markers following TLR3/4-primed-MSCs-CMs exposure in the glioma cell line. Notably, we observed a considerable induction of selective pro-apoptotic markers and both the early and late stages of apoptosis in treated U87 cell lines. Additionally, the migration rate of glioma cells significantly decreased following MSCs-CM treatment. Conclusion: Our findings confirmed that the exposure of TLR3/4-activated-MSCs-CMs with glioma tumour cells possibly changes the immunogenicity of the tumour microenvironment and induces immunogenic programmed cell death. Our results can support the idea that TLR3/4-primed-MSCs can lead to innate immune-mediated cell death and modify tumour cell biology in invasive and metastatic cancers.

The Sixth Sense: Self-nucleic acid sensing in the brain.

Our innate immune system uses pattern recognition receptors (PRRs) as a first line of defense to detect microbial ligands and initiate an immune response. Viral nucleic acids are key ligands for the activation of many PRRs and the induction of downstream inflammatory and antiviral effects. Initially it was thought that endogenous (self) nucleic acids rarely activated these PRRs, however emerging evidence indicates that endogenous nucleic acids are able to activate host PRRs in homeostasis and disease. In fact, many regulatory mechanisms are in place to finely control and regulate sensing of self-nucleic acids by PRRs. Sensing of self-nucleic acids is particularly important in the brain, as perturbations to nucleic acid sensing commonly leads to neuropathology. This review will highlight the role of nucleic acid sensors in the brain, both in disease and homeostasis. We also indicate the source of endogenous stimulatory nucleic acids where known and summarize future directions for the study of this growing field.

An IL-17A-centric response to Epstein-Barr virus DNA mediated by dendritic Cell-T cell interactions.

Introduction: The Epstein-Barr virus has been associated with a considerable number of autoimmune diseases. We have previously demonstrated that EBV DNA enhances the production of IL-17A, a pro-inflammatory cytokine, via endosomal Toll-like receptor signalling. Methods: We used RNA-seq to analyze the transcriptional profile of mouse immune cells treated with EBV DNA. Results: We observed that EBV DNA upregulates an IL-17A-centric network of mediators. Ensemble Gene Set Enrichment Analysis (EGSEA) showed enriched expression of sets involved in inflammatory responses including IFNγ and TNF-α-associated pathways as well as proinflammatory diseases. On the other hand, while macrophages and B cells were somewhat able to induce an IL-17A response from T cells to EBV DNA, they were less potent than dendritic cells. EBV virions were also capable of eliciting the production of inflammatory mediators from dendritic cell-T cell cultures largely mirroring responses to the viral DNA. Conclusions: Given the wide prevalence of EBV in the population, our analyses reveal a network of mediators and cell types that may serve as therapeutic targets in a large proportion of people affected by autoimmune diseases.

Association of polymorphisms in TLR3 and TLR7 genes with susceptibility to COVID-19 among Iranian population: a retrospective case-control study.

Background and Objectives: Host genetic changes like single nucleotide polymorphisms (SNPs) are one of the main factors influencing susceptibility to viral infectious diseases. This study aimed to investigate the association between the host SNP of Toll-Like Receptor3 (TLR3) and Toll-Like Receptor7 (TLR7) genes involved in the immune system and susceptibility to COVID-19 in a sample of the Iranian population. Materials and Methods: This retrospective case-control study evaluated 244 hospitalized COVID-19 patients as the case group and 156 suspected COVID-19 patients with mild signs as the control group. The genomic DNA of patients was genotyped for TLR7 (rs179008 and rs179009) and TLR3 (rs3775291 and rs3775296) SNPs using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Results: A significant association between rs179008 SNP in the TLR7 gene and the susceptibility of COVID-19 was found between case and control groups. The AT genotype (Heterozygous) of TLR7 rs179008 A>T polymorphism showed a significant association with a 2.261-fold increased odds of COVID-19 (P=0.003; adjusted OR: 2.261; 99% CI: 1.117-4.575). In addition, a significant association between TC genotype of TLR7 rs179009 T>C polymorphism and increased odds of COVID-19 (P<0.0001; adjusted OR: 6.818; 99% CI: 3.149-14.134) were determined. The polymorphism frequency of TLR3 rs3775291 and rs3775296 genotypes were not significantly different between the case and control groups (P> 0.004167). Conclusion: SNPs in TLR7 rs179008 and rs179009 genotypes are considered host genetic factors that could be influenced individual susceptibility to COVID-19. The SNPs in TLR3 (rs3775296 and rs3775291) showed no significant association with COVID-19 in Iranian population.

Poly I:C elicits broader and stronger humoral and cellular responses to a Plasmodium vivax circumsporozoite protein malaria vaccine than Alhydrogel in mice.

Malaria remains a global health challenge, necessitating the development of effective vaccines. The RTS,S vaccination prevents Plasmodium falciparum (Pf) malaria but is ineffective against Plasmodium vivax (Pv) disease. Herein, we evaluated the murine immunogenicity of a recombinant PvCSP incorporating prevalent polymorphisms, adjuvanted with Alhydrogel or Poly I:C. Both formulations induced prolonged IgG responses, with IgG1 dominance by the Alhydrogel group and high titers of all IgG isotypes by the Poly I:C counterpart. Poly I:C-adjuvanted vaccination increased splenic plasma cells, terminally-differentiated memory cells (MBCs), and precursors relative to the Alhydrogel-combined immunization. Splenic B-cells from Poly I:C-vaccinated mice revealed an antibody-secreting cell- and MBC-differentiating gene expression profile. Biological processes such as antibody folding and secretion were highlighted by the Poly I:C-adjuvanted vaccination. These findings underscore the potential of Poly I:C to strengthen immune responses against Pv malaria.

Poly(I:C) and R848 ligands show better adjuvanticity to induce B and T cell responses against the antigen(s).

Poly(I:C) and R848, synthetic ligands that activate Toll-like receptor 3 (TLR3) and TLR7/8 respectively, have been well-established for their ability to stimulate the immune system and induce antigen-specific immune responses. These ligands are capable of inducing the production of cytokines and chemokines, and hence support the activation and differentiation of B and T cells. We saw the long-lasting and perdurable immune responses by these adjuvants essentially required for an efficacious subunit vaccine. In this study, we investigated the potential of poly(I:C) and R848 to elicit B and T cell responses to the OVA antigen. We assessed the stimulatory effects of these ligands on the immune system, their impact on B and T cell activation, and their ability to enhanced generation of B and T cells. Collectively, our findings contribute to the understanding how poly(I:C) and R848 can be utilized as an adjuvant system to enhance immune responses to protein-based subunit vaccines. In the end, this work provides insights for the development of novel vaccination strategies and improving the vaccine efficacy. Present work shall help formulate newer strategies for subunit vaccines to address the infectious diseases.

TMEM2 suppresses TLR3-mediated IFN-ß/ISG56/CXCL10 expression in BEAS-2B bronchial epithelial cells.

BACKGROUND: Bronchial epithelial cells are at the front line of viral infections. Toll-like receptor 3 (TLR3) cascade causes the expression of interferon (IFN)-ß and IFN-stimulated genes (ISGs), which in turn induce an antiviral response. Members of the transmembrane protein (TMEM) family are expressed in various cell types. Although the prognostic value of TMEM2 in various cancers has been reported, its association with infectious diseases remains unknown. In this study, we investigated the effects of TMEM2 on antiviral immunity in BEAS-2B bronchial epithelial cells. METHODS AND RESULTS: TMEM2 protein was found in the cytoplasm of normal human bronchial epithelial cells and differed between organs using immunohistochemistry. Cultured BEAS-2B cells were transfected with TMEM2 siRNA, followed by administration of TLR3 ligand polyinosinic-polycytidylic acid (poly IC) or recombinant human (r(h)) IFN-ß. The expression of TMEM2, IFN-ß, ISG56, C-X-C motif chemokine ligand 10 (CXCL10) and hyaluronan were evaluated appropriately by western blotting, quantitative reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. TMEM2 expression was not altered by poly IC stimulation. Knockdown of TMEM2 increased poly IC-induced expression of IFN-ß, CXCL10, and ISG56, while IFN-ß-induced expression of ISG56 and CXCL10 were not changed by TMEM2 knockdown. The hyaluronan concentration in the medium was decreased by either TMEM2 knockdown or poly IC, but additive or synergistic effects were not observed. CONCLUSIONS: TMEM2 knockdown enhanced TLR3-mediated IFN-ß, CXCL10, and ISG56 expression in BEAS-2B cells. This implies that TMEM2 suppresses antiviral immune responses and prevents tissue injury in bronchial epithelial cells.