Pathogenicity of novel hantavirus isolate and antigenicity and immunogenicity of novel strain-based inactivated vaccine.

BACKGROUND: Hantaan virus (HTNV, Orthohantavirus hantanensae species, Hantaviridae family) is the main etiological agent responsible for hemorrhagic fever with renal syndrome (HFRS). The novel HTNV may pose a potential danger to the control and prevention of HFRS in China, which highlights the importance of vaccine development in public health management. In previous studies, our laboratory discovered and successfully isolated a new HTNV strain, HV004 strain, from Apodemus agrarius captured in an epidemic area in Hubei, China. METHODS: An initial biological and pathogenicity characterization of HTNV 76-118 (standard train), HV114 strain (a clinical isolate from Hubei province in 1986), and the novel isolate HV004 strain from the epidemic areas of Hubei province were performed in susceptible cells and in vivo. An experimental HV004 strain inactivated vaccine was prepared, and its corresponding immunogenicity was analyzed in BALB/c mice. RESULTS: HV004 strain had a similar but higher pathogenicity than HTNV 76-118 and HV114 in suckling mice. A subcutaneous vaccination (s.c.) with the inactivated HTNV vaccine adjuvanted with aluminum, followed by a challenge intraperitoneally with 106 FFU/ml HTNV, afforded full protection against an HTNV challenge. All immunized mice in every group elicited serum neutralizing antibodies with increasing dosages, which may protect mice from HTNV infection. A dose-dependent stimulation index of splenocytes was also observed in immunized mice. The percentage of IFN-γ-producing CD3+CD8+ T cells was significantly higher in the spleens of immunized mice than in those of control mice. CONCLUSIONS: These findings suggest that the inactivated HTNV vaccine may stimulate mice to produce high levels of antibodies with neutralization activity and elicit specific anti-HTNV humoral and cellular immune responses in BALB/c mice against the prevalent strain of HTNV in south central China.

Incidence of Orthohantavirus infection in humans follows observed changes in rodent reservoirs, Hubei Province, China (1984-2010).

OBJECTIVE: Orthohantaviruses (genus Orthohantavirus, family Hantaviridae of order Bunyavirales) are rodent-borne viruses causing 2 human diseases: hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS), which are mainly prevalent in Eurasia and the Americas, respectively. We initiated this study to investigate and analyze the Orthohantaviruses infection in rodent reservoirs and humans in the Hubei Province of China from 1984 to 2010. SAMPLE: The study included 10,314 mouse and 43,753 human serum samples. PROCEDURES: In this study, we analyzed the incidence of Orthohantavirus infection in humans and observed changes in rodent reservoirs in Hubei Province. RESULTS: The results indicated that although the incidence of HFRS declined from the 1990s, the human inapparent infection did not decrease dramatically. Although elements of the disease ecology have changed over the study period, Apodemus agrarius and Rattus norvegicus remain the major species and a constituent ratio of Rattus norvegicus increased. Rodent population density fluctuated between 16.65% and 2.14%, and decreased quinquennially, showing an obvious downward trend in recent years. The average orthohantaviruses-carrying rate was 6.36%, of which the lowest rate was 2.92% from 2006 to 2010. The analysis of rodent species composition showed that Rattus norvegicus and Apodemus agrarius were the dominant species over time (68.6% [1984 to 1987] and 90.4% [2000 to 2011]), while the composition and variety of other species decreased. The density of rodents was closely related to the incidence of HFRS (r = 0.910, P = .032). CLINICAL RELEVANCE: Our long-term investigation demonstrated that the occurrence of HFRS is closely related to rodent demographic patterns. Therefore, rodent monitoring and rodent control measures for prevention against HFRS in Hubei are warranted.

Effect of low-dose aspirin on mortality and viral duration of the hospitalized adults with COVID-19.

ABSTRACT: To clarify the effect of aspirin on mortality and viral duration in adults infected with respiratory syndrome coronavirus 2 (SARS-Cov-2).After propensity score-matched (PSM) case-control analyses 24 pairs of patients were enrolled and followed up for 2 months. Both 30-day and 60-day mortality in the aspirin group were significantly lower than that in the non-aspirin group (P = .021 and P = .030, respectively). The viral duration time between the 2 groups was not significantly different (P = .942).Among adults (with hypertension, cardiovascular diseases) infected with SARS-Cov-2, low-dose aspirin medication (100 mg/day) was associated with lower risk of mortality compared with non-aspirin users.

Antiviral Properties of R. tanguticum Nanoparticles on Herpes Simplex Virus Type I In Vitro and In Vivo.

Herpes simplex virus type 1 (HSV-1), an enveloped DNA virus, plays a key role in varieties of diseases including recurrent cold sores, keratoconjunctivitis, genital herpes and encephalitis in humans. Great efforts have been made in developing more effective and less side-effects anti-herpes simplex virus agents, including traditional Chinese herbal medicines. In the present study, we evaluated the antiviral efficacy of Rheum tanguticum nanoparticles against HSV-1 in vitro and in vivo. R. tanguticum nanoparticles could inactivate the HSV-1 virions and block the viral attachment and entry into cells. Time-of-addition assay indicated that R. tanguticum nanoparticles could interfere with the entire phase of viral replication. Besides, R. tanguticum nanoparticles showed the ability to inhibit the mRNA expression of HSV-1 immediate early gene ICP4 and early gene ICP8 as well as the expression of viral protein ICP4 and ICP8. Moreover, R. tanguticum nanoparticles have been proved to protect mice against HSV-1 induced lethality by decreasing the viral load and alleviated pathological changes in brain tissues. In conclusion, we demonstrated that R. tanguticum nanoparticles could inhibit HSV-1 infection through multiple mechanisms. These results suggest that R. tanguticum nanoparticles may have novel roles in the treatment of HSV-1 infection.

Assessment of a new arbidol derivative against herpes simplex virus II in human cervical epithelial cells and in BALB/c mice.

As one of the highly contagious forms, herpes simplex virus type 2 (HSV-2) commonly caused severe genital diseases and closely referred to the HIV infection. The lack of effective vaccines and drug-resistance proclaimed the preoccupation for alternative antiviral agents against HSV-2. Molecules bearing indole nucleus presented diverse biological properties involving antiviral and anti-inflammatory activities. In this study, one of the indole molecules, arbidol derivative (ARD) was designed and synthesized prior to the evaluation of its anti-HSV-2 activity. Our data showed that the ARD effectively suppressed HSV-2-induced cytopathic effects and the generation of progeny virus, with 50% effective concentrations of 3.386 and 1.717 µg/mL, respectively. The results of the time-course assay suggested that the ARD operated in a dual antiviral way by interfering virus entry and impairing the earlier period of viral cycle during viral DNA synthesis. The ARD-mediated HSV-2 inhibition was partially attained by blocking NF-κB pathways and down-regulating the expressions of several inflammatory cytokines. Furthermore, in vivo studies showed that oral administration of ARD protected BALB/c mice from intravaginal HSV-2 challenge by alleviating serious vulval lesions and histopathological changes in the target organs. Besides, the treatment with ARD also made the levels of viral protein, NF-κB protein and inflammatory cytokines lower, in consistent with the in-vitro studies. Collectively, ARD unveiled therapeutic potential for the prevention and treatment of HSV-2 infections.

Antiviral activity of arbidol hydrochloride against herpes simplex virus I in vitro and in vivo.

Herpes simplex virus type 1 (HSV-1) causes significant human diseases ranging from skin lesions to encephalitis, especially in neonates and immunocompromised hosts. The discovery of novel anti-HSV-1 drugs with low toxicity is required for public health. Arbidol hydrochloride (ARB) is an indole derivative molecule with broad-spectrum antiviral activity. In this study, the antiviral effects of ARB against HSV-1 infection were evaluated in vitro and in vivo. The results showed that ARB presents significant inhibitory effect on HSV-1 plaque formation and generation of progeny virus, with EC50 values (50% effective concentration) of 5.39 µg/mL (10.49 µM) and 2.26 µg/mL (4.40 µM), respectively. Moreover, time-of-addition and time-of-removal assays further suggested that ARB has viral inhibitory effects when added up to 12 h post-infection (p.i.), which could be further corroborated by determining the expression of viral immediate-early (ICP4, ICP22 and ICP27), early (ICP8 and UL42) and late (gB, gD, gH, VP1/2 and VP16) genes by real-time quantitative PCR as well as the expression of viral protein ICP4 and ICP8 at 6 h and 12 h p.i. Results of the in vivo study showed that ARB could reduce guinea pig skin lesions caused by HSV-1 infection. Conclusively, this report offers new perspectives in the search for therapeutic measures in the treatment of HSV-1 infection.

Specific Expression of Interferon-γ Induced by Synergistic Activation Mediator-Derived Systems Activates Innate Immunity and Inhibits Tumorigenesis.

The synergistic activation mediator (SAM) system can robustly activate endogenous gene expression by a single-guide RNA. This transcriptional modulation has been shown to enhance gene promoter activity and leads to epigenetic changes. Human interferon-γ is a common natural glycoprotein involved in antiviral effects and inhibition of cancer cell growth. Large quantities of high-purity interferon-γ are important for medical research and clinical therapy. To investigate the possibility of employing the SAM system to enhance endogenous human interferon-γ with normal function in innate immunity, we designed 10 single-guide RNAs that target 200 bp upstream of the transcription start sites of the interferon-γ genome, which could significantly activate the interferon-γ promoter reporter. We confirmed that the system can effectively and highly activate interferon-γ expression in several humanized cell lines. Moreover, we found that the interferon-γ induced by the SAM system could inhibit tumorigenesis. Taken together, our results reveal that the SAM system can modulate epigenetic traits of non-immune cells through activating interferon-γ expression and triggering JAK-STAT signaling pathways. Thus, this strategy could offer a novel approach to inhibit tumorigenesis without using exogenous interferon-γ.

Human bocavirus induces apoptosis and autophagy in human bronchial epithelial cells.

Human bocavirus (HBoV) is classified in the Bocavirus genus within the Parvoviridae family, first identified from children with respiratory diseases. Previous studies have investigated the stimulating effect of HBoV on cell apoptosis and autophagy. In the present study, human bronchial epithelial cells (HBECs) were utilized to examine the mechanism of HBoV recombination expressing vector (pWHL-1) on the promotion of cell apoptosis and autophagy. The results from the present study indicated that pWHL-1 inhibited the proliferation of HBECs in a time-dependent manner. Additionally, pWHL-1induced apoptosis, as substantiated by an increased apoptotic rate and presence of autophagosomes. Following pWHL-1 transfection, proliferating cell nuclear antigen, caspase-3 and B cell lymphoma 2 (Bcl-2) protein expression levels were decreased, with the exception of Bcl-2 associated × (Bax) protein, which increased. mRNA and protein expression levels of microtubule-associated protein 1A/1B-light chain 3 (LC3) II and autophagy protein 5 were increased in pWHL-1-transfected HBECs, whereas, the mRNA and protein levels of LC3I and sequestosome 1 were decreased. Notably, pWHL-1 also enhanced the activation of p53 and inhibited AKT activation in HBECs. Results from the present study suggest that pWHL-1 induces apoptosis and autophagy, thus providing a novel insight into the effect of HBoV and its uses in respiratory diseases.

Phylogenetic analysis based on mitochondrial DNA sequences of wild rats, and the relationship with Seoul virus infection in Hubei, China.

Seoul virus (SEOV), which is predominantly carried by Rattus norvegicus, is one of the major causes of hemorrhagic fever with renal syndrome (HFRS) in China. Hubei province, located in the central south of China, has experienced some of the most severe epidemics of HFRS. To investigate the mitochondrial DNA (mtDNA)-based phylogenetics of wild rats in Hubei, and the relationship with SEOV infection, 664 wild rats were captured from five trapping sites in Hubei from 2000-2009 and 2014-2015. Using reverse-transcription (RT)-PCR, 41 (6.17%) rats were found to be positive for SEOV infection. The SEOV-positive percentage in Yichang was significantly lower than that in other areas. The mtDNA D-loop and cytochrome b (cyt-b) genes of 103 rats were sequenced. Among these animals, 37 were SEOV-positive. The reconstruction of the phylogenetic relationship (based on the complete D-loop and cyt-b sequences) allowed the rats to be categorized into two lineages, R. norvegicus and Rattus nitidus, with the former including the majority of the rats. For both the D-loop and cyt-b genes, 18 haplotypes were identified. The geographic distributions of the different haplotypes were significantly different. There were no significant differences in the SEOVpositive percentages between different haplotypes. There were three sub-lineages for the D-loop, and two for cyt-b. The SEOV-positive percentages for each of the sub-lineages did not significantly differ. This indicates that the SEOV-positive percentage is not related to the mtDNA D-loop or cyt-b haplotype or the sub-lineage of rats from Hubei.

Human cytomegalovirus glycoprotein polymorphisms and increasing viral load in AIDS patients.

BACKGROUND: Multiple strains infection of human cytomegalovirus (HCMV) was found to be correlated with increased viral load in immunodeficient patients. However, the pathogenic mechanism underlying this correlation remains unclear. To evaluate genetic polymorphisms of HCMV glycoprotein and their potential role in its viral load, HCMV glycoprotein B, N, and O (gB, gN and gO) genotypes was studied in the population of HCMV infected acquired immune deficiency syndrome (AIDS) patients. The association between glycoprotein polymorphisms and HCMV viral load was analyzed. METHODS: The genetic polymorphisms of glycoprotein from sera of 60 HCMV infected AIDS patients was investigated by multiplex nested PCR and sequencing. HCMV viral load was evaluated by quantitative PCR. RESULTS: gB1, gO1a, and gN4a were the predominant glycoprotein genotypes in HCMV infected AIDS patients and composed 86.96%, 78.8%, and 49.2%, respectively. Only gN4a genotype infection significantly increased viral load (P = 0.048). 71% (43/60) of HCMV infected AIDS patients were found to carry multiple HCMV strains infection. A novel potential linkage of gO1a/gN4a was identified from multiple HCMV infected patients. It was the most frequent occurrence, accounted for 51.5% in 33 patients with gO and gN genotypes infection. Furthermore, the gO1a/gN4a linkage was correlated to an increased viral load (P = 0.020). CONCLUSION: The gN4a correlates to higher level HCMV load in AIDS patients. Interestingly, a novel gO1a/gN4a linkage is identified from the patients with multiple HCMV strains infection and is also associated with an increased viral load. Therefore, the pathogenic mechanism underlying glycoprotein polymorphisms and interaction of variants should be analyzed further.

Diversity, evolution and population dynamics of avian influenza viruses circulating in the live poultry markets in China.

Live poultry markets (LPMs) are an important source of novel avian influenza viruses (AIV). During 2015-2016 we surveyed AIV diversity in ten LPMs in Hubei, Zhejiang and Jiangxi provinces, China. A high diversity and prevalence of AIVs (totaling 12 subtypes) was observed in LPMs in these provinces. Strikingly, however, the subtypes discovered during 2015-2016 were markedly different to those reported by us in these same localities one year previously, suggesting a dynamic shift in viral genetic diversity over the course of a single year. Phylogenetic analyses revealed frequent reassortment, including between high and low pathogenic AIV subtypes and among those that circulate in domestic and wild birds. Notably, the novel H5N6 reassortant virus, which contains a set of H9N2-like internal genes, was prevalent in all three regions surveyed. Overall, these data highlight the profound changes in genetic diversity and in patterns of reassortment in those AIVs that circulate in LPMs.

Construction of a Seasonal Difference-Geographically and Temporally Weighted Regression (SD-GTWR) Model and Comparative Analysis with GWR-Based Models for Hemorrhagic Fever with Renal Syndrome (HFRS) in Hubei Province (China).

Hemorrhagic fever with renal syndrome (HFRS) is considered a globally distributed infectious disease which results in many deaths annually in Hubei Province, China. In order to conduct a better analysis and accurately predict HFRS incidence in Hubei Province, a new model named Seasonal Difference-Geographically and Temporally Weighted Regression (SD-GTWR) was constructed. The SD-GTWR model, which integrates the analysis and relationship of seasonal difference, spatial and temporal characteristics of HFRS (HFRS was characterized by spatiotemporal heterogeneity and it is seasonally distributed), was designed to illustrate the latent relationships between the spatio-temporal pattern of the HFRS epidemic and its influencing factors. Experiments from the study demonstrated that SD-GTWR model is superior to traditional models such as GWR- based models in terms of the efficiency and the ability of providing influencing factor analysis.

Antivirals for Respiratory Viral Infections: Problems and Prospects.

In the past two decades, several newly emerging and reemerging viral respiratory pathogens including several influenza viruses (avian influenza and pandemic influenza), severe acute respiratory syndrome coronavirus (SARS-CoV), and Middle East respiratory syndrome coronavirus (MERS-CoV), have continued to challenge medical and public health systems. Thereafter, the development of cost-effective, broad-spectrum antiviral agents is the urgent mission of both virologists and pharmacologists. Current antiviral developments have focused targets on viral entry, replication, release, and intercellular pathways essential for viral life cycle. Here, we review the current literature on challenges and prospects in the development of these antivirals.

pH-dependent conformational changes of a Thogoto virus matrix protein reveal mechanisms of viral assembly and uncoating.

Orthomyxoviruses are a family of ssRNA virus, including influenza virus, infectious salmon anaemia virus and Thogoto virus. The matrix proteins of orthomyxoviruses play crucial roles in some essential processes of the viral life cycle. However, the mechanisms of the matrix proteins involved in these processes remain incompletely understood. Currently, only the structure and function of the matrix protein from influenza virus have been studied. Here, we present the crystal structures of the N-terminal domain of matrix protein from Thogoto virus at pH 7.0 and 4.5. By analysing the structures, we identified the conformational changes of monomers and dimers in different pH conditions, mainly caused by two flexible loops, L3 and L5. These structural deviations would reflect the basis of viral capsid assembly or disassembly.

Specific interference shRNA-expressing plasmids inhibit Hantaan virus infection in vitro and in vivo.

AIM: To investigate the antiviral effects of vectors expressing specific short hairpin RNAs (shRNAs) against Hantaan virus (HTNV) infection in vitro and in vivo. METHODS: Based on the effects of 4 shRNAs targeting different regions of HTNV genomic RNA on viral replication, the most effective RNA interference fragments of the S and M genes were constructed in pSilencer-3.0-H1 vectors, and designated pSilencer-S and pSilencer-M, respectively. The antiviral effect of pSilencer-S/M against HTNV was evaluated in both HTNV-infected Vero-E6 cells and mice. RESULTS: In HTNV-infected Vero-E6 cells, pSilencer-S and pSilencer-M targeted the viral nucleocapsid proteins and envelope glycoproteins, respectively, as revealed in the immunofluorescence assay. Transfection with pSilencer-S or pSilencer-M (1, 2, 4 µg) markedly inhibited the viral antigen expression in dose- and time-dependent manners. Transfection with either plasmid (2 µg) significantly decreased HTNV-RNA level at 3 day postinfectin (dpi) and the progeny virus titer at 5 dpi. In mice infected with lethal doses of HTNV, intraperitoneal injection of pSilencer-S or pSilencer-M (30 µg) considerably increased the survival rates and mean time to death, and significantly reduced the mean virus yields and viral RNA level, and alleviated virus-induced pathological lesions in lungs, brains and kidneys. CONCLUSION: Plasmid-based shRNAs potently inhibit HTNV replication in vitro and in vivo. Our results provide a basis for development of shRNA as therapeutics for HTNV infections in humans.

Diversity and evolution of avian influenza viruses in live poultry markets, free-range poultry and wild wetland birds in China.

The wide circulation of novel avian influenza viruses (AIVs) highlights the risk of pandemic influenza emergence in China. To investigate the prevalence and genetic diversity of AIVs in different ecological contexts, we surveyed AIVs in live poultry markets (LPMs), free-range poultry and the wetland habitats of wild birds in Zhejiang and Hubei provinces. Notably, LPMs contained the highest frequency of AIV infection, and the greatest number of subtypes (n = 9) and subtype co-infections (n = 14), as well as frequent reassortment, suggesting that they play an active role in fuelling AIV transmission. AIV-positive samples were also identified in wild birds in both provinces and free-range poultry in one sampling site close to a wetland region in Hubei. H9N2, H7N9 and H5N1 were the most commonly sampled subtypes in the LPMs from Zhejiang, whilst H5N6 and H9N2 were the dominant subtypes in the LPMs from Hubei. Phylogenetic analyses of the whole-genome sequences of 43 AIVs revealed that three reassortant H5 subtypes were circulating in LMPs in both geographical regions. Notably, the viruses sampled from the wetland regions and free-range poultry contained complex reassortants, for which the origins of some segments were unclear. Overall, our study highlights the extent of AIV genetic diversity in two highly populated parts of central and south-eastern China, particularly in LPMs, and emphasizes the need for continual surveillance.

The cytokine storm of severe influenza and development of immunomodulatory therapy.

Severe influenza remains unusual in its virulence for humans. Complications or ultimately death arising from these infections are often associated with hyperinduction of proinflammatory cytokine production, which is also known as 'cytokine storm'. For this disease, it has been proposed that immunomodulatory therapy may improve the outcome, with or without the combination of antiviral agents. Here, we review the current literature on how various effectors of the immune system initiate the cytokine storm and exacerbate pathological damage in hosts. We also review some of the current immunomodulatory strategies for the treatment of cytokine storms in severe influenza, including corticosteroids, peroxisome proliferator-activated receptor agonists, sphingosine-1-phosphate receptor 1 agonists, cyclooxygenase-2 inhibitors, antioxidants, anti-tumour-necrosis factor therapy, intravenous immunoglobulin therapy, statins, arbidol, herbs, and other potential therapeutic strategies.

High Human Cytomegalovirus IgG Level is Associated with Increased Incidence of Diabetic Atherosclerosis in Type 2 Diabetes Mellitus Patients.

BACKGROUND At present, whether human cytomegalovirus (HCMV) infection is associated with type 2 diabetes mellitus (T2DM) is debatable. The effect of active HCMV infection on glucose regulation has been poorly studied. Although HCMV infection is correlated with atherosclerosis in cardiovascular disease, the role of HCMV infection in the development of diabetic atherosclerosis in T2DM is unclear and is usually neglected by endocrinologists. The aim of this study was to assess the effects of HCMV infection on glucose regulation and the development of diabetic atherosclerosis in T2DM patients. MATERIAL AND METHODS A total of 222 hospitalized T2DM patients were enrolled. Nested polymerase chain reactions were used to detect HCMV DNA extracted from peripheral blood leukocytes. Quantitative real-time PCR was used to determine viral load. HCMV IgG antibody concentrations were analyzed by chemiluminescence immunoassay. RESULTS HCMV active infection, viral load, and HCMV IgG titers were not correlated with glucose regulation. Binary logistic regression demonstrated that the highest quartile of HCMV IgG concentration (>500 U/ml) was correlated with the incidence of diabetic atherosclerosis (OR: 8.0, 95%CI: 2.3-27.2), and that titer >127 U/ml of HCMV IgG is an independent predictor for the development of diabetic atherosclerosis in T2DM patients (OR: 4.6, 95%CI: 1.9-11.3) after adjustment for all potential confounding factors. CONCLUSIONS Active HCMV infection is unlikely to influence glucose regulation in T2DM. However, HCMV IgG titers are associated with the incidence of diabetic atherosclerosis, and titer >127 U/ml of HCMV IgG might be an independent risk factor for the development of diabetic atherosclerosis in T2DM patients.

Antiviral effect of emodin from Rheum palmatum against coxsakievirus B5 and human respiratory syncytial virus in vitro.

Viral infections are the major causes of morbidity and mortality in elderly people and young children throughout the world. The most common pathogens include coxsackie virus (CV) and respiratory syncytial virus (RSV). However, no antiviral agents with low toxicity and drug resistance are currently available in clinic therapy. The present study aimed to examine the antiviral activities of emodin (an ingredient of Rheum palmatum) against CVB5 and RSV infections, in an attempt to discover new antiviral agents for virus infection. The monomer emodin was extracted and isolated from Rheum palmatum. The antiviral activities of emodin on HEp-2 cells were evaluated, including virus replication inhibition, virucidal and anti-absorption effects, by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tet-razolium bromide (MTT) assay and plaque reduction assay (PRA). The kinetics of virus inhibition by emodin in a period of 14 h was further determined by plaque assay and quantitative real time PCR (qPCR). Cytokine (IFN-γ, TNF-α) mRNA expressions after emodin treatment (7.5, 15, 30 µmol/L) were also assessed by qPCR post-infection. The results showed that emodin had potent inhibitory activities against CVB5 and RSV, with the 50% effective concentration (EC50) ranging from 13.06 to 14.27 µmol/L and selectivity index (SI) being 5.38-6.41 µmol/L. However, emodin couldn't directly inactivate the viruses or block their absorption to cells. It acted as a biological synthesis inhibitor against CVB4 and RSV in a concentration- and time-dependent manner, especially during the first 0-4 h post-infection. Moreover, emodin could decrease the mRNA expression of IFN-α but enhance TNF-γ expression significantly compared to the viral controls in vitro. Our results provide a molecular basis for development of emodin as a novel and safe antiviral agent for human enterovirus and respiratory virus infection in the clinical therapy.