NOX1/NADPH oxidase affects the development of autism-like behaviors in a maternal immune activation model.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder caused by genetic and environmental factors. Among the environmental factors, maternal infection is known as one of the principal risk factors for ASD. On the other hand, postmortem studies suggested the relationship of oxidative stress with ASD etiology. However, the role of oxidative stress in the development of ASD remains unclear. Here, we report the involvement of NOX1/NADPH oxidase, an enzyme generating reactive oxygen species (ROS), in behavioral and anatomical abnormalities in a maternal immune activation (MIA) model. In the MIA model of gestational polyinosinic-polycytidylic acid (poly(I:C)) exposure, increased serum levels of IL-6 were observed in both wild-type (WT) and Nox1-deficient mice (Nox1KO). Following the comparable induction of MIA in the two genotypes, impairment of social preference and defects in motor coordination were observed in WT offspring but not in offspring deficient in Nox1. MIA up-regulated NOX1 mRNA in the cerebral cortex and cerebellum of the fetus but not in the adult offspring. Although the development of cortical neurons was unaffected by MIA in either genotype, the dropout of Purkinje cells in lobule VII of MIA-affected offspring was significantly ameliorated in Nox1KO. Taken together, these results suggested that NOX1/NADPH oxidase plays an essential role in some behavioral phenotypes observed in ASD, possibly by promoting the loss of Purkinje cells in the cerebellum.

The endogenous inflammatory reflex inhibits the inflammatory response to different immune challenges in mice.

The splanchnic anti-inflammatory pathway, the efferent arm of the endogenous inflammatory reflex, has been shown to suppress the acute inflammatory response of rats to systemic lipopolysaccharide (LPS). Here we show for the first time that this applies also to mice, and that the reflex may be engaged by a range of inflammatory stimuli. Experiments were performed on mice under deep anaesthesia. Half the animals were subjected to bilateral section of the splanchnic sympathetic nerves, to disconnect the splanchnic anti-inflammatory pathway, while the remainder underwent a sham operation. Mice were then challenged intravenously with one of three inflammatory stimuli: the toll-like receptor (TLR)-4 agonist, LPS (60 µg/kg), the TLR-3 agonist Polyinosinic:polycytidylic acid (Poly I:C, 1 mg/kg) or the TLR-2 and -6 agonist dipalmitoyl-S-glyceryl cysteine (Pam2cys, 34 µg/kg). Ninety minutes later, blood was sampled by cardiac puncture for serum cytokine analysis. The splanchnic anti-inflammatory reflex action was assessed by comparing cytokine levels between animals with cut versus those with intact splanchnic nerves. A consistent pattern emerged: Tumor necrosis factor (TNF) levels in response to all three challenges were raised by prior splanchnic nerve section, while levels of the anti-inflammatory cytokine interleukin 10 (IL-10) were reduced. The raised TNF:IL-10 ratio after splanchnic nerve section indicates an enhanced inflammatory state when the reflex is disabled. These findings show for the first time that the inflammatory reflex drives a coordinated anti-inflammatory action also in mice, and demonstrate that its anti-inflammatory action is engaged, in similar fashion, by inflammatory stimuli mimicking a range of bacterial and viral infections.

Toll-like receptor 3 agonist poly I:C reinforces the potency of cytotoxic chemotherapy via the TLR3-UNC93B1-IFN-ß signaling axis in paclitaxel-resistant colon cancer.

Type I interferon (IFN) signaling in neoplastic cells has a chemo-sensitizing effect in cancer therapy. Toll-like receptor 3 (TLR3) activation promotes IFN-ß production, which induces apoptosis and impairs proliferation in some cancer cells. Herein, we tested whether the TLR3 agonist polyinosinic: polycytidylic acid (poly I:C) can improve chemotherapeutic efficacy in paclitaxel (PTX) resistant cell lines. Human colon cancer cell lines HCT116, SW620, HCT-8 (sensitive to PTX), and HCT-8/PTX (resistant to PTX) were treated with poly I:C and the cell viability was measured. Results showed that poly I:C specifically impaired the cell viability of HCT-8/PTX by simultaneously promoting cell apoptosis and inhibiting cell proliferation. In addition, when TLR3 was overexpressed in HCT-8/PTX cells, we found that TLR3 contributed to the production of IFN-ß that reduced cell viability, and poly I:C preferentially activated the TLR3-UNC93B1 signaling pathway to mediate this effect. Moreover, cotreatment of poly I:C and PTX acted synergistically to induce cell apoptosis of HCT-8/PTX via upregulating the expression of TLR3 and its molecular chaperone UNC93B1, assisting in the secretion of IFN-ß. Notably, a combination of poly I:C and PTX synergistically inhibited the PTX-resistant tumor growth in vivo without side effects. In conclusion, our studies demonstrate that poly I:C reinforces the potency of cytotoxic chemotherapeutics in PTX-resistant cell line through the TLR3-UNC93B1-IFN-ß signaling pathway, which supplies a novel mechanism of poly I:C for the chemotherapy sensitizing effect in a PTX-resistant tumor.

A multi-CRD C-type lectin gene Cnlec-1 enhance the immunity response in noble scallop Chlamys nobilis with higher carotenoids contents through up-regulating under different immunostimulants.

C-type lectins have a variety of immunological functions in invertebrates. In order to investigate whether C-type lectin gene and carotenoids do have immune influences on noble scallop Chlamys nobilis under pathogen stress, acute challenges lasting 48 h to Vibrio parahaemolyticus, lipopolysaccharide (LPS), polyinosinic polycytidylic acid (Poly I: C), and PBS were conducted in noble scallop with different carotenoids content. A multi-CRD C-type lectin gene called Cnlec-1 was cloned and its transcripts under different challenges were determined. Full length cDNA of Cnlec-1 is 2267 bp with an open reading frame (ORF) of 1845 bp encoding 614 deduced amino acids, containing four carbohydrate recognition domains (CRD1, CRD2, CRD3 and CRD4). Phylogenetic tree analysis showed that CRDs of Cnlec-1 were clustered with CRDs of shellfish C-type lectins, especially closely related to Chlamys farreri and Argopecten irradians CRDs. Cnlec-1 transcripts were detected in hemocytes, mantle, gonad, kidney, intestines, gill and adductor. Compared with PBS control group, Cnlec-1 transcripts were up-regulated in V. parahaemolyticus, LPS and Poly I: C groups. Furthermore, Cnlec-1 transcript levels of Golden scallops were significantly higher than that of Brown ones at 3-48 h (P < 0.05) in V. parahemolyticus groups, at 24 h in LPS groups and at 12-24 h in Poly I: C groups. These results suggesting that Cnlec-1 is an important immune factor involved in the defense against pathogens in the noble scallop, and carotenoids can enhance the immunity of noble scallop through up-regulating Cnlec-1 to different immunostimulants.

Cloning and differential expression of a novel toll-like receptor gene in noble scallop Chlamys nobilis with different total carotenoid content.

To investigate whether toll like receptors (TLRs) genes do have an immune influence on noble scallop Chlamys nobilis under pathogen stress, acute challenges lasting 48 h to Vibrio parahaemolyticus, lipopolysaccharide (LPS), polyinosinic polycytidylic acid (Poly I:C), and PBS were conducted in two scallop stains of orange and brown with different carotenoids content. A novel toll-like receptor gene called CnTLR-1 was cloned and its transcripts under different challenges were determined. Meantime, total carotenoids content (TCC) of different immune responses were determined to investigate whether there was a relationship between gene expression and carotenoids content. The full length cDNA of CnTLR-1 is 2982 bp with an open reading frame (ORF) of 1920 bp encoding 639-deduced amino acids, which contains five leucine-rich repeats (LRR), two LRR-C-terminal (LRRCT) motifs and a LRR-N-terminal (LRRNT) motif in the extracellular domain, a transmembrane domain and a Toll/Interleukin-1 Receptor (TIR) of 138-amino acids in the cytoplasmic region. Phylogenetic tree analysis showed that CnTLR-1 could be clustered with mollusk TLRs into one group and especially was related closely to Crassostrea gigas and Mytilus galloprovincialis TLRs. CnTLR-1 transcripts were detected in decreasing levels in the mantle, hemocytes, gill, kidney, gonad, hepatopancreas, intestines and adductor. Compared with PBS control group, CnTLR-1 transcripts were up-regulated in V. parahaemolyticus, LPS and Poly I:C groups. Further, CnTLR-1 transcripts were significantly higher in orange scallops than that of brown ones with and without pathogenic challenges. TCC, which is higher in orange scallops, was initially increased and then decreased during a 48 h immune challenge in the hemocytes. The present results indicate that CnTLR-1 is an important factor involved in the immune defense against pathogens in the noble scallop.

Selection of Reference Genes for Gene Expression Studies in Porcine Whole Blood and Peripheral Blood Mononuclear Cells under Polyinosinic:Polycytidylic Acid Stimulation.

Investigating gene expression of immune cells of whole blood or peripheral blood mononuclear cells (PBMC) under polyinosinic:polycytidylic acid (poly I:C) stimulation is valuable for understanding the immune response of organism to RNA viruses. Quantitative real-time PCR (qRT-PCR) is a standard method for quantification of gene expression studies. However, the reliability of qRT-PCR data critically depends on proper selection of reference genes. In the study, using two different analysis programs, geNorm and NormFinder, we systematically evaluated the gene expression stability of six candidate reference genes (GAPDH, ACTB, B2M, RPL4, TBP, and PPIA) in samples of whole blood and PBMC with or without poly I:C stimulation. Generally, the six candidate genes performed a similar trend of expression stability in the samples of whole blood and PBMC, but more stably expressed in whole blood than in PBMC. geNorm ranked B2M and PPIA as the best combination for gene expression normalization, while according to NormFinder, TBP was ranked as the most stable reference gene, followed by B2M and PPIA. Comprehensively considering the results from the two programs, we recommended using the geometric mean of the three genes, TBP, PPIA and B2M, to normalize the gene expression of whole blood and PBMC with poly I:C stimulation. Our study is the first detailed survey of the gene expression stability in whole blood and PBMC with or without poly I:C stimulation and should be helpful for investigating the molecular mechanism involved in porcine whole blood and PBMC in response to poly I:C stimulation.

Effects of bacterial and viral pathogen-associated molecular patterns (PAMPs) on multidrug resistance (MDR) transporters in brain endothelial cells of the developing human blood-brain barrier.

BACKGROUND: The multidrug resistance (MDR) transporters, P-glycoprotein (P-gp, encoded by ABCB1) and breast cancer resistance protein (BCRP/ABCG2) contribute to the blood-brain barrier (BBB), protecting the brain from drug exposure. The impact of infection on MDR in the developing human BBB remains to be determined. We hypothesized that exposure to bacterial and viral pathogen-associated molecular patterns (PAMPs) modify MDR expression and activity in human fetal brain endothelial cells (hfBECs) isolated from early and mid-gestation brain microvessels. METHODS: We modelled infection (4 h and 24 h) using the bacterial PAMP, lipopolysaccharide (LPS; a toll-like receptor [TLR]-4 ligand) or the viral PAMPs, polyinosinic polycytidylic acid (Poly I:C; TLR-3 ligand) and single-stranded RNA (ssRNA; TLR-7/8 ligand). mRNA expression was assessed by qPCR, whereas protein expression was assessed by Western blot or immunofluorescence. P-gp and BCRP activity was evaluated by Calcein-AM and Chlorin-6 assays. RESULTS: TLRs-3,4 and 8 were expressed by the isolated hfBECs. Infection mimics induced specific pro-inflammatory responses as well as changes in P-gp/ABCB1 or BCRP/ABCG2 expression (P < 0.05). LPS and ssRNA significantly decreased P-gp activity at 4 and 24 h in early and mid-gestation (P < 0.03-P < 0.001), but significantly increased BCRP activity in hfBECs in a dose-dependent pattern (P < 0.05-P < 0.002). In contrast, Poly-IC significantly decreased P-gp activity after 4 h in early (P < 0.01) and mid gestation (P < 0.04), but not 24 h, and had no overall effect on BCRP activity, though BCRP activity was increased with the highest dose at 24 h in mid-gestation (P < 0.05). CONCLUSIONS: Infectious PAMPs significantly modify the expression and function of MDR transporters in hfBECs, though effects are PAMP-, time- and dose-specific. In conclusion, bacterial and viral infections during pregnancy likely have profound effects on exposure of the fetal brain to physiological and pharmacological substrates of P-gp and BCRP, potentially leading to altered trajectories of fetal brain development.

Tofacitinib Downregulates TNF and Poly(I:C)-Dependent MHC-II Expression in the Colonic Epithelium.

Major Histocompatibility Complex (MHC)-I and -II genes are upregulated in intestinal epithelial cells (IECs) during active inflammatory bowel diseases (IBD), but little is known about how IBD-relevant pro-inflammatory signals and IBD drugs can regulate their expression. We have previously shown that the synthetic analog of double-stranded RNA (dsRNA) Polyinosinic:polycytidylic acid (Poly(I:C)), induces interferon stimulated genes (ISGs) in colon organoids (colonoids). These ISGs may be involved in the induction of antigen presentation. In the present study, we applied colonoids derived from non-IBD controls and ulcerative colitis patients to identify induction and effects of IBD-drugs on antigen presentation in IECs in the context of Tumor Necrosis Factor (TNF)-driven inflammation. By RNA sequencing, we show that a combination of TNF and Poly(I:C) strongly induced antigen-presentation gene signatures in colonoids, including expression of MHC-II genes. MHC-I and -II protein expression was confirmed by immunoblotting and immunofluorescence. TNF+Poly(I:C)-dependent upregulation of MHC-II expression was associated with increased expression of Janus Kinases JAK1/2 as well as increased activation of transcription factor Signal transducer and activator of transcription 1 (STAT1). Accordingly, pre-treatment of colonoids with IBD-approved pan-Janus Kinase (JAK) inhibitor Tofacitinib led to the downregulation of TNF+Poly(I:C)-dependent MHC-II expression associated with the abrogation of STAT1 activation. Pre-treatment with corticosteroid Budesonide, commonly used in IBD, did not alter MHC-II expression. Collectively, our results identify a regulatory role for IBD-relevant pro-inflammatory signals on MHC-II expression that is influenced by Tofacitinib.

Poly (I: C) inhibits reticuloendothelial virus replication in chicken macrophage-like cells through the activation of toll-like receptor-3 signaling.

Reticuloendothelial virus (REV) is widely found in many domestic poultry areas and results in severe immunosuppression of infected chickens. This increases the susceptibility to other pathogens, which causes economic losses to the poultry industry. The aim of our study was to determine whether polyinosinic-polycytidylic acid [Poly (I: C)] treatment could inhibit REV replication in chicken macrophage-like cell line, HD11. We found that Poly (I: C) treatment could markedly inhibit REV replication in HD11 from 24 to 48 h post infection (hpi). Additionally, Poly (I: C) treatment could switch HD11 from an inactive type into M1-like polarization from 24 to 48 hpi. Furthermore, Poly (I: C) treatment promoted interferon-ß secretion from HD11 post REV infection. Moreover, Toll-like receptor-3 (TLR-3) mRNA and protein levels in HD11 treated with Poly (I: C) were markedly increased compared to those of HD11 not treated with Poly (I: C). The above results suggested that Poly (I: C) treatment switches HD11 into M1-like polarization to secret more interferon-ß and activate TLR-3 signaling, which contributes to block REV replication. Our findings provide a theoretical reference for further studying the underlying pathogenic mechanism of REV and Poly (I: C) as a potential therapeutic intervention against REV infection.

Paliperidone Reversion of Maternal Immune Activation-Induced Changes on Brain Serotonin and Kynurenine Pathways.

Emerging evidence indicates that early-life exposure to environmental factors may increase the risk for schizophrenia via inflammatory mechanisms. Inflammation can alter the metabolism of tryptophan through the oxidative kynurenine pathway to compounds with neurotoxic and neuroprotective activity and compromise serotonin (5-HT) synthesis. Here we investigate the role of serotonergic and kynurenine pathways in the maternal immune activation (MIA) animal model of schizophrenia. The potential reversion exerted by long-term antipsychotic treatment was also evaluated. MIA was induced by prenatal administration of polyinosinic:polycytidylic acid (poly (I:C)) in mice. Expression of different proteins and the content of different metabolites involved in the function of serotonergic and kynurenine pathways was assessed by RT-PCR, immunoblot and ELISA analyses in frontal cortex of the offspring after puberty. MIA decreased tissue 5-HT content and promoted changes in the expression of serotonin transporter, 5-HT2A and 5-HT2C receptors. Expression of indoleamine 2,3-dioxygenase 2 (IDO2) and kynurenine 3-monooxygenase (KMO) was increased by poly (I:C) whereas kynurenine aminotransferase II and its metabolite kynurenic acid were not altered. Long-term paliperidone was able to counteract MIA-induced changes in 5-HT and KMO, and to increase tryptophan availability and tryptophan hydroxylase-2 expression in poly (I:C) mice but not in controls. MIA-induced increase of the cytotoxic risk ratio of kynurenine metabolites (quinolinic/kynurenic acid) was also reversed by paliperidone. MIA induces specific long-term brain effects on serotonergic activity. Such effects seem to be related with alternative activation of the kynurenine metabolic pathway towards a cytotoxic status. Atypical antipsychotic paliperodine partially remediates abnormalities observed after MIA.

Elevated maternal retinoic acid-related orphan receptor-γt enhances the effect of polyinosinic-polycytidylic acid in inducing fetal loss.

T helper 17 (Th17) cells have been suggested to play a crucial role in various complications during pregnancy by participating in maternal immune activation (MIA). To test a possible role for Th17 cells in MIA-mediated abortion, we analyzed transgenic mice overexpressing retinoic acid receptor-related orphan receptor gamma-t (RORγt), a master regulator of IL-17 producing cell development. These mutant mice (RORγt Tg mice) exhibited a constitutive upregulation of serum IL-17A and decreased E-cadherin expression in cell-cell junctions of placental tissues. Abortion after the administration of a viral-mimicking synthetic double-stranded RNA polyinosinic-polycytidylic acid was more frequent in RORγt Tg mice than wild-type mice. These results suggest that excessive Th17 cell activity alters immune responsiveness and increases the rate of abortion during gestation.

Layer-by-layer nanocoating of live Bacille-Calmette-Guérin mycobacteria with poly(I:C) and chitosan enhances pro-inflammatory activation and bactericidal capacity in murine macrophages.

Tuberculosis (TB) is a major disease burden globally causing more than 1.5 million deaths per year. The attenuated live vaccine strain Bacille Calmette-Guérin (BCG), although providing protection against childhood TB, is largely ineffective against adult pulmonary TB. A major aim therefore is to increase the potency of the BCG vaccine to generate stronger and more sustained immunity against TB. Here, we investigated the use of layer-by-layer (LbL) nanocoating of the surface of live BCG with several layers of polyinosinic-polycytidylic acid (poly(I:C)), a strong inducer of cell-mediated immunity, and the biodegradable polysaccharide chitosan to enhance BCG immunogenicity. Nanocoating of live BCG did not affect bacterial viability or growth in vitro but induced killing of the BCG in infected mouse bone marrow-derived macrophages and enhanced macrophage production of pro-inflammatory cytokines and expression of surface co-stimulatory molecules relative to uncoated BCG. In addition, poly(I:C) surface-coated BCG, but not BCG alone or together with soluble poly(I:C), induced high production of nitric oxide (NO) and IL-12. These results argue that BCG and surface absorbed poly(I:C) act in a synergistic manner to elicit pro-inflammatory macrophage activation. In conclusion, nanocoating of live BCG with the immunostimulatory agent poly(I:C) may be an appropriate strategy to enhance and modulate host responses to the BCG vaccine.

Transcriptomic Analysis Identifies Candidate Genes and Gene Sets Controlling the Response of Porcine Peripheral Blood Mononuclear Cells to Poly I:C Stimulation.

Polyinosinic-polycytidylic acid (poly I:C), a synthetic dsRNA analog, has been demonstrated to have stimulatory effects similar to viral dsRNA. To gain deep knowledge of the host transcriptional response of pigs to poly I:C stimulation, in the present study, we cultured and stimulated peripheral blood mononuclear cells (PBMC) of piglets of one Chinese indigenous breed (Dapulian) and one modern commercial breed (Landrace) with poly I:C, and compared their transcriptional profiling using RNA-sequencing (RNA-seq). Our results indicated that poly I:C stimulation can elicit significantly differentially expressed (DE) genes in Dapulian (g = 290) as well as Landrace (g = 85). We also performed gene set analysis using the Gene Set Enrichment Analysis (GSEA) package, and identified some significantly enriched gene sets in Dapulian (g = 18) and Landrace (g = 21). Most of the shared DE genes and gene sets were immune-related, and may play crucial rules in the immune response of poly I:C stimulation. In addition, we detected large sets of significantly DE genes and enriched gene sets when comparing the gene expression profile between the two breeds, including control and poly I:C stimulation groups. Besides immune-related functions, some of the DE genes and gene sets between the two breeds were involved in development and growth of various tissues, which may be correlated with the different characteristics of the two breeds. The DE genes and gene sets detected herein provide crucial information towards understanding the immune regulation of antiviral responses, and the molecular mechanisms of different genetic resistance to viral infection, in modern and indigenous pigs.

Bacterial and viral induction of chicken thrombocyte inflammatory responses.

Thrombocytes express Toll-like receptors (TLRs) that detect bacterial or viral pathogens to signal the release of cytokines and mediators. We examined inflammatory responses when thrombocytes were exposed to four TLR ligands. Treatment of thrombocytes with TLR ligands demonstrates differential effects on gene expression of interleukin (IL)-6. Among the TLR ligands examined, lipopolysaccharide stimulation led to the most significant up-regulation of the IL-6 gene and a significant amount of active IL-6 in thrombocyte culture media. Lipoteichoic acid stimulation led to only marginal up-regulation of IL-6 gene expression. Although gene expression of inducible nitric oxide synthase (iNOS) did not increase due to different ligand exposure, a low level constitutive expression of iNOS was observed in all cases. Only thrombocytes treated with polyinosinic-polycytidylic acid and thymidine homopolymer phosphorothioate oligodeoxynucleotides induced rapid, significant production of nitric oxide. We also observed that thrombocytes are able to respond faster upon TLR ligand exposure compared to MQ.NCSU macrophages.

The poly(I:C)-induced maternal immune activation model in preclinical neuropsychiatric drug discovery.

Increasing epidemiological and experimental evidence implicates gestational infections as one important factor involved in the pathogenesis of several neuropsychiatric disorders. Corresponding preclinical model systems based upon maternal immune activation (MIA) by treatment of the pregnant female have been developed. These MIA animal model systems have been successfully used in basic and translational research approaches, contributing to the investigation of the underlying pathophysiological mechanisms at the molecular, cellular and behavioral levels. The present article focuses on the application of a specific MIA rodent paradigm, based upon treatment of the gestating dam with the viral mimic polyinosinic-polycytidilic acid (Poly(I:C)), a synthetic analog of double-stranded RNA (dsRNA) which activates the Toll-like receptor 3 (TLR3) pathway. Important advantages and constraints of this animal model will be discussed, specifically in light of gestational infection as one vulnerability factor contributing to the complex etiology of mood and psychotic disorders, which are likely the result of intricate multi-level gene×environment interactions. Improving our currently incomplete understanding of the molecular pathomechanistic principles underlying these disorders is a prerequisite for the development of alternative therapeutic approaches which are critically needed in light of the important drawbacks and limitations of currently available pharmacological treatment options regarding efficacy and side effects. The particular relevance of the Poly(I:C) MIA model for the discovery of novel drug targets for symptomatic and preventive therapeutic strategies in mood and psychotic disorders is highlighted in this review article.

Comparison of polycytidylic acid-induced and dexamethasone-induced thymic atrophy and their thymic expression of RIG-Ⅰ like receptors signaling pathway / 中国免疫学杂志

Objective:To provide experimental evidences for choosing murine models in the pathogenesis research of thymic impairment induced by viral infection,we compared the impacts of polycytidylic acid(Poly(I:C)) and dexamethasone(DEX) on the thymic morphology and thymic output function,and explored the implication of RLR signaling pathway.Methods: 24 male C57BL/6 mice were randomly assigned into three groups and treated with Poly(I:C),DEX,or saline respectively.Thereafter,their thymic morphology,pathological changes,thymic index,and thymic pathology were examined.Their contents of T-cell receptor excision circles (TRECs) and proportions of the naive CD4+T cell in the peripheral blood were determined to evaluate their thymic output function.The expression levels of thymic RLR/MAVS/IFN-α/β signaling pathway and IL-1β were also measured.Results: Both Poly (I:C) and DEX treatment caused thymic atrophy in appearance and structural destruction under the microscope inspection,and DEX treatment did much more severe damage,especially to the thymic cortex.TRECs decreased significantly in both groups.The proportions of na?ve/memory CD4+T cell subsets remained stable,though total CD4+T cell decreased in DEX group,while the proportion of na?ve CD4+T cell in Poly (I:C) group increased significantly.The expression of RIG-Ⅰ,MDA5,LGP2,and IFN-α/β were up-regulated in DEX group, while it remained unchanged in Poly (I:C) group.Conclusion:Both Poly (I:C) and DEX induced thymic atrophy and the impaired thymic output function.Nevertheless,the expression of RLR-IFN signaling pathway up-regulated more significantly in DEX group instead of in Poly (I:C) group.These results implied the existence of different pathological manifestations and mechanisms underlying the impaired thymic function in different animal models,as well as impact on na?ve/memory CD4+T cell proportions.Our research provides references for choosing animal models in the basic research and drug development for viral infection induced thymic atrophy based on the RLR signaling pathway.