Human respiratory syncytial virus (RSV) is the leading cause of severe lower respiratory tract infection, such as bronchiolitis, bronchitis, or pneumonia, in both infants and the elderly. Despite the global burden of diseases attributable to RSV infection, no clinically approved vaccine is available, and a humanized monoclonal antibody for prophylaxis is not readily affordable in developing countries. There are several hurdles to the successful development of RSV vaccines: immune-vulnerable target populations such as premature infants, pregnant women, and immunocompromised people; safety concerns associated with vaccine-enhanced diseases; repeated infection; and waning memory. To develop successful strategies for the prevention of RSV infection, it is necessary to understand the protective and pathologic roles of host immune responses to RSV infection. In this review, we will summarize the positive and negative relationship between RSV infection and host immunity and discuss strategies for the development of the first successful RSV vaccine.
Humans ; Immunity ; Immunocompromised Host ; Respiratory Syncytial Virus Infections/immunology/*prevention & control ; *Respiratory Syncytial Virus Vaccines ; Respiratory Syncytial Viruses/*physiology

The respiratory syncytial virus (RSV) is one of the most common causes of acute infection of the lower respiratory tract among children. For viruses in the Paramyxoviridae subfamily, membrane fusion requires a specific interaction between two glycoproteins: the fusion protein and attachment protein. Membrane fusion of the RSV appears to be unique among paramyxoviruses in that fusion is accomplished by the fusion protein alone without help from the attachment protein. Here, we review recent achievements and advances in the study of membrane fusion triggered by the RSV published in high-impact-factor journals. We also review and make a comparative analysis of the popular hypotheses regarding membrane fusion of the RSV. Finally, we discuss the "hot topics" in current research and controversial data published in recent years in the hope of providing references for Chinese researchers.
Animals ; Humans ; Respiratory Syncytial Virus Infections ; virology ; Respiratory Syncytial Viruses ; genetics ; physiology ; Viral Fusion Proteins ; genetics ; metabolism ; Virus Internalization

This study was to establish a model to explore anti- RSV effect of different administration method of Chinese medicine realgar on respiratory syncytial virus type A (RSV-A) replication in Hep-2 cells. Using high-energy ball milling with distilled water to prepare realgar nanoparticles,the concentration of nanometer realgar was tested by molybdenum blue staining method and the size of realgar nanoparticles was tested on Nano Series. Cell culture with ribavirin as a positive control was applied to observe the effect of anti-respiratory syncytial virus type A replication through prevention, treatment or direct inactivation of three different drug administration methods. Realgar nano-particles was found to be a potential inhibitor of RSV-A in a concentration-dependent manner with the median toxic concentration(TC50) of 0.649 microg/mL in Hep-2 cell culture. The median inhibition concentration (IC50) was 0.20 microg/mL when drug was added before virus infection. The IC50 was 0.13 microg/mL when drug was added after virus infection,and it was 0.16 microg/mL when the drug was mixed with virus and added. The therapeutic index (TI) was 3.18, 4.99 and 4.11, respectively. The results showed realgar nanoparticles could inhibit the replication of the RSV and inactivate the RSV in vitro.
Arsenicals ; pharmacology ; Nanoparticles ; Respiratory Syncytial Viruses ; drug effects ; physiology ; Sulfides ; pharmacology ; Virus Replication ; drug effects

OBJECTIVETo understand the clinical characteristics and outcome associated with respiratory syncytial virus (RSV) infection in hematopoietic stem cell transplantation (HSCT) recipients with primary immunodeficiencies (PIDs).

METHODNasopharyngeal aspirate samples were collected consecutively before and after HSCT from 9 recipients from Apr. 2009 to Sep. 2010 and analyzed for the presence of RSV using real-time polymerase chain reaction assay. To further verify the presence of the virus, positive samples for PCR were isolated for RSV. RSV G gene was amplified, sequenced and used for phylogenetic analysis.

RESULTThe presence of RSV was detected in 3 out of 9 children. The viral replication in all the patients was prolonged for months. All the 3 patients with RSV infection were treated with intravenous immune globulin (IVIG) and one was treated with antiviral medication. All patients survived and achieved successful immune reconstitution.

CONCLUSIONThis study indicates that the HSCT recipients with PID are at increased risk for RSV infection. RSV can shed for months after the initial infection and the patients recover with the course of immune reconstitution.

Child, Preschool ; Female ; Hematopoietic Stem Cell Transplantation ; adverse effects ; Humans ; Immunologic Deficiency Syndromes ; surgery ; virology ; Infant ; Prognosis ; Respiratory Syncytial Virus Infections ; diagnosis ; drug therapy ; Respiratory Syncytial Viruses ; genetics ; isolation & purification ; physiology ; Virus Replication ; Virus Shedding

AIMTo study the relation between Respiratory Syncytial Virus infection and asthma development by measuring airway responsiveness (AR) and M2R function.

METHODSGuinea pigs (n = 34) were randomly divided into 4 groups: Hep-2/NS group (group A, n = 9), RSV/NS group (group B, n =9), Hep-2/OVA group (group C, n = 8) and RSV/OVA group(group D, n = 8). On day 21 after infection we tested AR and M2R. Then counted eosinophils in BALF and observed pathological change.

RESULTSIntraairway pressure(IP mmH20) of group B had no significant difference with group A(P > 0.01), and the extent of IP decrease also had no difference between groups A and B (P > 0. 05), but IP of C group were much higher than group A (P<0.05), with extent of IP decrease lower than group A (P < 0.05). And IP of group D were higher than group C (P < 0.01), with the extent of IP decrease much lower than group C (P < 0.05).

CONCLUSIONRSV infection could enhance OVA-induced M2R dysfunction, then develop AHR.

Animals ; Asthma ; immunology ; physiopathology ; virology ; Bronchial Hyperreactivity ; immunology ; physiopathology ; virology ; Female ; Guinea Pigs ; Male ; Ovalbumin ; immunology ; Random Allocation ; Receptor, Muscarinic M2 ; physiology ; Respiratory Syncytial Virus Infections ; immunology ; Respiratory Syncytial Viruses ; immunology

OBJECTIVEDNAzyme/Deoxyribozyme is another novel molecular biological tool following the ribozyme. DNAzyme consists of a 15-nucleotide (nt) internal loop as its catalytic domain and two flanking substrate-recognition domains of 7 to 8 nt each which is complementary to substrate. The RNA substrate is cleaved at a particular phosphodiester located between an unpaired purine and a paired pyrimidine residue. DNAzyme has been applied in fields such as viral infectious disease, tumor, cardiovascular disease and genetic disease. But there is no report about using DNAzyme for anti-respiratory syncytial virus purpose. To observe the inhibitory effects of RNA-cleaving DNAzymes on respiratory syncytial virus (RSV) replication in cultured cells.

METHODSAnti-RSV RNA-cleaving DNAzyme DZ604 was designed to target the RSV genome at the start of the NS2 gene in an effort to inhibit the RNA replication. Microscope and electron microscope were used to observe the effects of anti-RSV genomic RNA DNAzyme on cytopathogenic effect (CPE) and ultrastructural change of 9HTE cell induced by RSV infection. Viral plaque forming reduction assay and MTT assay were used to detect the anti-RSV activity and protective function for RSV infected 9HTE cells of DNAzyme.

RESULTSAnti-RSV genomic RNA DNAzyme (DZ604) significantly improved CPE of RSV-infected 9HTE cells. The time to appearance of CPE and of total CPE was delayed by using DZ604 in a dose-dependent manner. At a 5 micro mol/L concentration of DZ604, CPE of 9HTE cells induced by RSV infection at 10 and 1 multiplicity of infection (MOI) was not improved. At smaller MOI (0.1, 0.01, 0.001, 0.0001) of RSV infection, CPE of 9HTE cells was significantly lightened by DZ604 at the same concentration. DZ604 also significantly improved ultrastructural change of 9HTE cells at early stage of RSV infection. Reduction in RSV yield was 85.56% and 8.33% at concentrations of 5 micro mol/L and 0.25 micro mol/L of DZ604. DZ604 inhibited RSV yield in a dose-dependent manner (P < 0.05). Non-specific DNAzyme did not have anti-RSV activity (P > 0.05).

CONCLUSIONAnti-RSV genomic RNA DNAzyme designed and synthesized in our laboratory was capable of inhibiting respiratory syncytial virus replication specifically in cultured cells. Our data indicated that DNAzymes could be useful for the prevention against respiratory syncytial virus infection.

Animals ; Cell Line ; Cercopithecus aethiops ; DNA, Catalytic ; pharmacology ; Dose-Response Relationship, Drug ; Humans ; Microscopy, Electron ; Respiratory Mucosa ; cytology ; ultrastructure ; virology ; Respiratory Syncytial Viruses ; drug effects ; genetics ; physiology ; Vero Cells ; Virus Replication ; drug effects

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.
Antiviral Agents ; pharmacology ; Cell Line ; Cell Line, Tumor ; Emodin ; pharmacology ; Enterovirus B, Human ; drug effects ; physiology ; Humans ; In Vitro Techniques ; Respiratory Syncytial Viruses ; drug effects ; physiology ; Rheum ; chemistry ; Virus Replication

To investigate whether influenza virus (IFZ) could up-regulate the expression of mucin 1 (MUC1) which exists in epithelial cells of upper respiratory track to restrict the inflammation, as respiratory syncytial virus (RSV) does. Quantitative RT-PCR and Western Blot were performed to detect the expression level of MUC1 induced by two single-strand RNA viruses in A549 cell lines. HEp-2 and MDCK cells were used respectively to culture RSV and IFZ. At 24h post A549 cells infection with the same titer of RSV or IFZ, the total RNA was harvest, qRT-PCR was then performed to observe the expression level of MUC1 mRNA. Meanwhile, at 24 h and 48 h post A549 cells infection with the same titer of RSV or IFZ, the total protein and supernatant were collected respectively after cell lysis, Western Blot was then used to detect the expression level of MUC1. Results showed that RSV could up-regulate the expression of MUC1 in airway epithelial cells with a significant dose-effect correlation, whereas IFZ could not. This study firstly investigated the differences of the regulation on the expression of MUC1 induced by two single-strand RNA viruses, and demonstrated initially that the mechanism of IFZ self-limiting differed from RSV, which attributed to up-regulation of the expression level of MUC1.
Animals ; Cell Line ; Dogs ; Epithelial Cells ; metabolism ; virology ; Gene Expression Regulation ; Humans ; Influenza, Human ; genetics ; metabolism ; virology ; Madin Darby Canine Kidney Cells ; Mucin-1 ; genetics ; metabolism ; Orthomyxoviridae ; genetics ; physiology ; Respiratory Syncytial Virus Infections ; genetics ; metabolism ; virology ; Respiratory Syncytial Viruses ; genetics ; physiology ; Up-Regulation

OBJECTIVETo explore the mechanism of signal transduction in respiratory syncytial virus (RSV)-induced expression of thymic stromal lymphopoietin (TSLP) in bronchial epithelial cells.

METHODSThe eukaryotic expression vector of RSV F protein, pcDNA3-F, was constructed and transfected into in vitro cultured human bronchial epithelial cell line CRL-9483, which was also transfected with Smad7 expression vector pcDNA3/Smad7 or exposed to p38, ERK1/2, JNK, and JAK/STAT1 inhibitors. The mRNA levels of TSLP and the housekeeping GAPDH gene were analyzed 24 h later with semi-quantitative RT-PCR. In cells with downregulated TSLP mRNA expression due to the addition of the signal inhibitors, cytoplasm TSLP or GAPDH protein levels were further analyzed using Western blotting.

RESULTSVirtually no TSLP mRNA expression was detected by RT-PCR in cultured CRL-9483 cells transfected with pcDNA3 exclusively (TSLP/GAPDH relative total gray scale of 0.10-/+0.03), while cell transfection with pcDNA3-F resulted in significantly increased TSLP mRNA level (0.42-/+0.20, P=0.024). In the presence of F protein expression, both p38 and JNK inhibitors could downregulate TSLP mRNA levels (0.14-/+0.04, P=0.036; 0.23-/+0.07, P=0.048, respectively), while TGF-beta-Smad inhibiting protein Smad7 (0.60-/+0.25), ERK 1/2 inhibitor (0.45-/+0.23), and JAK/STAT1inhibitor (0.44-/+0.25) failed to block TSLP expression (P>0.05). Western blotting showed that p38 inhibitor (TSLP/GAPDH relative total gray scale=3.67-/+1.18, P=0.018) and JNK inhibitor (1.48-/+0.77, P=0.004) also downregulated the protein levels of TSLP as compared with pcDNA3-F transfection group (8.13-/+2.20).

CONCLUSIONRSV F protein can stimulate TSLP expression in human bronchial epithelial cells mediated partially by p38 and JNK signal pathways.

Bronchi ; cytology ; metabolism ; virology ; Cell Line ; Cytokines ; genetics ; metabolism ; Epithelial Cells ; metabolism ; virology ; Gene Expression ; Humans ; MAP Kinase Kinase 4 ; genetics ; metabolism ; Respiratory Syncytial Virus Infections ; genetics ; metabolism ; virology ; Respiratory Syncytial Viruses ; genetics ; physiology ; Signal Transduction ; Viral Fusion Proteins ; genetics ; metabolism ; p38 Mitogen-Activated Protein Kinases ; genetics ; metabolism

OBJECTIVETo evaluate the efficacy and safety of Qingkailing Injection (, QKL) for treatment of children pneumonia caused by respiratory syncytial virus (RSV).

METHODSRandomized clinical trials (RCTs) comparing QKL with ribavirin injection in the treatment of children pneumonia induced by RSV were searched in PubMed, Science Direct, Cochrane Library, Chinese VIP database, CNKI and Wanfang databases from their inception to March 2014. Meta-analyses were performed using RevMan 5.2 software. The methodological quality of the selected RCTs was evaluated by the Modified Jadad Score. The primary outcome measures were effective rate and the secondary outcomes were relief time of fever and cough.

RESULTSSeven RCTs with 992 cases published from 2008 to 2013 were identified. The meta-analysis results indicated that QKL was more effective in cure rate [risk ratios (RR)=1.32, 95% CI (1.17, 1.50), P<0.01], total effective rate [RR=1.07, 95% CI (1.02, 1.13), P=0.009] and less fever clearance time [mean difference=-0.73, 95% CI (-1.22,-0.23), P=0.004], compared with ribavirin injection in the treatment of RSV-induced children pneumonia. No dead case was reported in all trials. There were 3 trials mentioned adverse events, 2 reported no obvious adverse event occurred while 1 reported adverse events described as skin hypersensitivity, elevation of ALT, a mild abnormal of hepatic and renal function in both QKL and ribavirin group.

CONCLUSIONSQKL was an effective and relatively safe option for the treatment of RSV-induced children pneumonia. These therapeutic effects were promising but need to be interpreted with caution due to variations in the treatment and methodological weakness in the studies.

Cough ; complications ; drug therapy ; Drugs, Chinese Herbal ; administration & dosage ; adverse effects ; pharmacology ; therapeutic use ; Fever ; complications ; drug therapy ; Humans ; Injections ; Pneumonia ; drug therapy ; virology ; Publication Bias ; Randomized Controlled Trials as Topic ; Respiratory Syncytial Virus Infections ; complications ; drug therapy ; virology ; Respiratory Syncytial Viruses ; physiology ; Ribavirin ; therapeutic use