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[beta]-Adrenergic agonists ([beta]-agonists) are commonly used to treat respiratory syncytial virus (RSV) bronchiolitis but are generally ineffective for unknown reasons. We have previously shown that RSV strain A2 inhibits bronchoalveolar epithelial responses to [beta]-agonists in a BALB/c mouse model by inducing heterologous keratinocyte cytokine (KC)/CXCR2-mediated desensitization of epithelial [[beta].sub.2]-adrenergic receptors. The aim of the current study was to determine whether RSV also induces airway insensitivity to [beta]-agonists. Total lung resistance (R) was measured in anesthetized female BALB/c mice undergoing mechanical ventilation on a flexiVent computer-controlled piston ventilator. Data were analyzed using the single-compartment model. Infection with RSV A2 did not induce airway hyperresponsiveness to increasing doses of the nebulized cholinergic agonist methacholine (MCh) at any time point after RSV infection. Prenebulization with the [beta]-agonist terbutaline (100 [micro]M) significantly attenuated bronchoconstrictive responses to 20 and 50 mg/ml MCh in uninfected mice and in mice infected with RSV 4-8 days postinfection (d.p.i.). However, in mice infected with replication-competent, but not UV-inactivated, RSV for 2 days, significant terbutaline insensitivity was found. Terbutaline insensitivity at 2 d.p.i, could be reversed by systemic preinfection treatment with neutralizing anti-CXCR2 antibodies, which reduced bronchoalveolar lavage (BAL) neutrophil counts but did not alter viral replication, BAL KC levels, or lung edema. Terbutaline insensitivity was also reversed by postinfection nebulization with neutralizing anti-KC or anti-CXCR2 antibodies and could be replicated in normal, uninfected mice by nebulization with recombinant KC. These data suggest that KC/CXCR2-mediated airway insensitivity to [beta]-agonists may underlie the modest utility of these drugs as bronchodilators in therapy for acute RSV bronchiolitis. CXCL8; CXCR2; keratinocyte cytokine; airway hyperresponsiveness doi:10.1152/ajplung.00363.2009.

Respiratory syncytial virus (RSV) is the most common cause of hospitalization for respiratory tract infection in young children. It is also a significant cause of morbidity and mortality in elderly individuals and in persons with asthma and chronic obstructive pulmonary disease. Currently, no reliable vaccine or simple RSV antiviral therapy is available. Recently, we determined that the minor pulmonary surfactant phospholipid, palmitoyl-oleoyl-phosphatidyl-glycerol (POPG), Could markedly attenuate inflammatory responses induced by lipopolysaccharide through direct interactions with the Toll-like receptor 4 (TLR4) interacting proteins CD14 and MD-2. CD14 and TLR4 have been implicated in the host response to RSV. Treatment of bronchial epithelial cells with POPG significantly inhibited interleukin-6 and -8 production, as well as the cytopathic effects induced by RSV. The phospholipid bound RSV with high affinity and inhibited viral attachment to HEp2 cells. POPG blocked viral plaque formation in vitro by 4 log units, and markedly suppressed the expansion of plaques from cells preinfected with the virus. Administration of POPG to mice, concomitant with viral infection, almost completely eliminated the recovery of virus from the lungs at 3 and 5 days after infection, and abrogated IFN-[gamma] (IFN-[gamma]) production and the enhanced expression of surfactant protein D (SP-D). These findings demonstrate an important approach to prevention and treatment of RSV infections using exogenous administration of a specific surfactant phospholipid. antiviral | innate immunity | respiratory epithelium www.pnas.org/cgi/doi/10.1073/pnas.0909361107

A population-based study was conducted to establish the burden of respiratory syncytial virus (RSV) infection among young children hospitalized in the United States. Results indicated that RSV infection is associated with significant morbidity amongst hospitalized and outpatient young children, highlighting the need for better control strategies.

We have identified a single tryptophan (Trp) residue responsible for loss of binding and biological activity upon ultraviolet (UV) light irradiation in MEDI-493, a humanized monoclonal antibody (MAb) against respiratory syncytial virus (RSV). This finding provides a better understanding of structure-function relationship in a 150-kDa protein. Irradiation of MEDI-493 with UV light resulted in spectral changes typical of Trp photoproducts and in a progressive loss of MEDI-493 binding and biological activity as measured by ELISA, Biacore, and cell-based assays. Mass spectrometric characterization of the proteolytic peptides generated from the UV irradiated MEDI-493 confirmed that most methionine (Met) and a few Trp residues were oxidized to various extents upon exposure to UV light. Among Trp residues, only Trp-105, containing the most solvent-exposed indole moiety in MEDI-493 and residing in a complementary-determining region (CDR) of the heavy chain, was significantly oxidized. When bound to a synthetic antigenic peptide, MEDI-493 showed significant resistance toward binding activity loss during UV irradiation. A second MAb (MEDI-524) with Trp-105 replaced by phenylalanine (Phe) showed a similar pattern of Met oxidation, but no loss of binding and biological activity following irradiation. Treatment of both MAbs with Met- and Trp-specific oxidizing reagents showed that oxidation of Trp-105 correlated with the activity loss, whereas Met oxidation did not affect the activity. These results demonstrate that Trp-105 in MEDI-493 is responsible for the UV light-induced effects.

Respiratory syncytial virus (RSV) is a prominent cause of airway morbidity in children under 1 yr of age. It is assumed that host factors influence the severity of the disease presentation and thus the need for hospitalization. As a first step toward the identification of the underlying genes involved, this study was undertaken to establish whether inbred mouse strains differ in susceptibility to pneumonia virus of mice (PVM), the murine counterpart of RSV, which has been shown to accurately mimic the RSV disease of children. With this purpose in mind, double-chamber plethysmography and carbon monoxide uptake data were collected daily for 7 days after inoculation of PVM in six inbred strains of mice. In parallel, histological examinations and lung viral titration were carried out from day 5 to day 7 after inoculation. Pulmonary structure/function values reflected the success of viral replication in the lungs and revealed a pattern of continuous variation, with resistant, intermediate, and susceptible strains. The results suggest that SJL (resistant) and 129/Sv (susceptible) strains should be used in crossing experiments aimed at identifying genes controlling pneumovirus replication by the positional cloning approach. Similarly, crossing experiments using BALB/c or C57BL/6 (resistant) and DBA/2 or 129/Sv (susceptible) will allow the identification of the genes involved in the control of pulmonary inflammation during pneumovirus infection. pneumovirinae; respiratory syncytial virus; mouse; genetic resistance doi:10.1152/ajplung.00483.2004

Respiratory syncytial virus (RSV) matrix (M) nuclear import for the first time, showing that M is able to localize in the nucleus in the absence of other RSV gene products, through M amino acids 110-183 is examined. The M protein of RSV plays an important role in virus assembly through specific interactions with RSV nucleocapsids and envelope glycoproteins in the cytoplasm as well as with the host cell membrane.

The attachment protein (glycoprotein) of respiratory syncytial virus (RSV) has long been associated with disease potentiation and respiratory symptoms. The glycoprotein has a conserved cysteine-rich region (GCRR) whose function is unknown and which is not necessary for efficient viral replication. In this report, we show that the GCRR is a powerful inhibitor of the innate immune response against RSV, and that early secretion of glycoprotein is critical to modulate inflammation after RSV infection. Importantly, the GCRR is also a potent inhibitor of cytokine production mediated by several TLR agonists, indicating that this peptide sequence displays broad antiinflammatory properties. These findings have important implications for RSV pathogenesis and describe an inhibitor of TLR-mediated inflammatory responses that could have clinical applications. glycoprotein | innate immunity | Toll-like receptor 4

Objective. Use of palivizumab prophylactic therapy reduces the occurrence of hospitalizations for serious respiratory syncytial virus (RSV) lower respiratory tract infections in at-risk infants. The direct cost-benefit of palivizumab prophylaxis for infants who are born at 32 to 35 weeks' estimated gestational age (EGA) during their first year of life has not been systematically examined. The objective of this study was to compare the direct costs of palivizumab prophylaxis and RSV treatment in infants who were born at 32 to 35 weeks EGA and received and did not receive palivizumab. Methods. A cohort study was performed of infants who were younger than 1 year and were enrolled in an enhanced primary care case management model within the North Carolina Medicaid Program. Comparisons were made between infants who received (Synagis prophylaxis group) and did not receive palivizumab (nonprophylaxis group) during the study period. Cost was examined using the sum of Medicaid paid services for prophylaxis with palivizumab and treatment for RSV infections that occurred between October 1, 2002, and May 31, 2003. The Anderson framework was used to specify the regression cost models to compare the participants who received (Synagis prophylaxis) and did not receive (nonprophylaxis group) palivizumab. The primary outcomes were actual 7-month seasonal costs and standardized seasonal costs adjusting for the varied months of infant participation. Results. The study sample included 185 Synagis prophylaxis and 182 nonprophylaxis participants who met the inclusion criteria. The average per-person total cost of RSV care and prophylaxis was $5117 for the Synagis prophylaxis group and $371 for the nonprophylaxis group. Five hospitalizations occurred in the prophylaxis group, and 12 occurred in the nonprophylaxis group (odds ratio: 0.27). No deaths occurred in either group. Conclusions. Palivizumab administered to infants who were born at 32 to 35 weeks' EGA did not provide direct cost savings related to hospitalization or ambulatory care in a Medicaid population. The primary difference in cost between the groups was attributable to the palivizumab prophylaxis. ABBREVIATIONS. RSV, respiratory syncytial virus; EGA, estimated gestational age; CLD, chronic lung disease; AAP, American Academy of Pediatrics; PA, prior authorization., Respiratory syncytial virus (RSV) is the leading cause of serious lower respiratory tract infections in children. (1-7) Serious RSV disease, often measured by the need for hospitalization, is predominantly manifested [...]

Respiratory syncytial virus (RSV) is the major viral cause of serious lower respiratory tract illness in infants and young children worldwide. RSV infection is limited to the superficial layers of the respiratory epithelium in immunocompetent individuals. Consistent with this in vivo observation, we and others have found that RSV buds preferentially from the apical surface of infected polarized epithelial cells. In contrast, directional budding is not observed in nonpolarized human epithelial cells. These findings suggest that RSV uses specific cellular trafficking pathways to accomplish viral replication. The host cell proteins that regulate directional budding of RSV are undefined. Apical sorting of cellular proteins in polarized epithelial cells involves the apical recycling endosome (ARE). To investigate whether ARE-mediated protein sorting plays a role during RSV replication, we expressed a fragment of the myosin Vb tail that functions as a dominant negative inhibitor of ARE-mediated protein sorting in polarized Madin-Darby canine kidney cells. When these cells were infected with RSV, a >9,000-fold reduction in viral yield was observed. A similar effect on virus replication was observed when a carboxyl-terminal fragment of another ARE-associated protein, the Rab11 family interacting protein 1, was expressed in Madin-Darby canine kidney cells. These data suggest that RSV requires proper ARE-mediated protein sorting for efficient egress from the apical surface of polarized epithelial cells.

Respiratory syncytial virus (RSV) infection is associated with exaggerated neurogenic inflammation in the airways. This study sought to determine whether irritation of the mucosal sensory fibers affects the recruitment of lymphocytes and monocytes to RSV-infected airways. Pathogen-free rats were inoculated with RSV or with virus-free medium and were injected 5 days later with capsaicin to stimulate airway sensory nerves. Bronchoalveolar lavage was performed 1, 5, or 10 days after nerve stimulation, and samples were analyzed by differential cell count and flow cytometry. Without nerve stimulation, RSV caused a minimal increase in the number of lymphocytes and monocytes above pathogen-free control levels. After nerve stimulation, numerous lymphocytes, predominantly CD4+ T cells, and monocytes were recruited in the airways of infected rats, whereas no difference was found in pathogen-free controls. RSV induced overexpression of the neurokinin 1 (N[K.sup.1]) receptor for substance P on discrete lymphocyte subpopulations within the bronchial-associated lymphoid tissue (BALT), and treatment with a specific N[K.sup.1] receptor antagonist abolished the recruitment of both lymphocytes and monocytes to infected airways. Our data suggest that airborne irritants stimulating mucosal sensory fibers during RSV infection exert important immunomodulatory effects by attracting to the infected airways selected lymphocyte subpopulations from the local BALT as well as monocytes. airway inflammation; asthma; lymphocytes; monocytes; substance P

Byline: Eric A.F. Simoes (1), Anthony R. Hayward (2), Esther M. Ponnuraj (1), John P. Straumanis (3), Kurt R. Stenmark (3), Harry L. Wilson (4), P. George Babu (5) Keywords: Key words: bronchiolitis, pneumonia, animal models, respiratory syncytial virus, bronchoalveolar lavage, Bonnet monkeys Abstract: The Bonnet monkey model of respiratory syncytial virus (RSV) infection may be a useful nonhuman primate model for studying RSV disease in humans because Bonnet monkeys can predictably be infected to obtain an orderly sequence of morphologic, cytologic, virologic, serologic, and inflammatory changes related to time of infection. Young feral Bonnet monkeys, Macaca radiata, were infected endotracheally with 10.sup.6 plaque-forming units (pfu) of the Long strain of RSV. RSV was recovered from the animals' lungs at necropsy on days 3, 5, and 7 with the highest viral titer obtained on day 3 (1.1 and 5.2x10.sup.3 pfu/g of tissue in the upper and lower lobes, respectively). RSV antigen and F protein mRNA were detected 3--5 days after infection in alveolar macrophages and in the epithelium of bronchi, terminal bronchioles, and alveoli. Histologic analysis of RSV-infected lungs at necropsy revealed progressive bronchiolar mucosal and submucosal inflammation, periarterial mononuclear interstitial inflammation, and focal alveolitis, with a maximal response at 7 days after infection. Cell counts in bronchoalveolar lavage (BAL) increased with time with neutrophils and macrophages predominating on day 3 (6.47 and 5.85x10.sup.5/mm.sup.3, respectively) and lymphocytes predominating on day 9 (4.18x10.sup.5/mm.sup.3). Serum-neutralizing antibody appeared on day 5 and IgG antibody to RSV was detected on day 9. This sequence of morphologic, cytologic, virologic, serologic, and inflammatory change following RSV infection creates a useful model in the study of experimentally induced RSV disease with a potential for testing future vaccine-induced alterations in RSV disease response. Author Affiliation: (1) Department of Pediatrics, Division of Pediatric Infectious Diseases, University of Colorado Health Sciences Center, Denver, CO 80262, USA , US (2) Department of Pediatrics, Division of Immunology, University of Colorado Health Sciences Center, Denver, CO 80262, USA , US (3) Department of Pediatrics, Developmental Lung Biology Laboratories, University of Colorado Health Sciences Center, Denver, CO 80262, USA , US (4) Department of Pathology, Providence Memorial Hospital, El Paso, TX 79902, USA , US (5) Department of Virology, Christian Medical College Hospital, Vellore, India 632004 , IN Article note: Received March 20, 1998 accepted September 7, 1998.

Interferon [Gamma] (IFN-[Gamma]) has pleiotropic biological effects, including intrinsic antiviral activity as well as stimulation and regulation of immune responses. An infectious recombinant human respiratory syncytial virus (rRSV/mIFN-[Gamma]) was constructed that encodes murine (m) IFN-[Gamma] as a separate gene inserted into the G-F intergenic region. Cultured cells infected with rRSV/mIFN-[Gamma] secreted 22 [[micro]gram] mIFN-[Gamma] per [10.sup.6] cells. The replication of rRSV/mIFN-[Gamma], but not that of a control chimeric rRSV containing the chloramphenicol acetyl transferase (CAT) gene as an additional gene, was 63- and 20-fold lower than that of wild-type (wt) RSV in the upper and lower respiratory tract, respectively, of mice. Thus, the attenuation of rRSV/mIFN-[Gamma] in vivo could be attributed to the activity of mIFN-[Gamma] and not to the presence of the additional gene per se. The mice were completely resistant to subsequent challenge with wt RSV. Despite its growth restriction, infection of mice with rRSV/mIFN-[Gamma] induced a level of RSV-specific antibodies that, on day 56, was comparable to or greater than that induced by infection with wt RSV. Mice infected with rRSV/mIFN-[Gamma] developed a high level of IFN-[Gamma] mRNA and an increased amount of interleukin 12 p40 mRNA in their lungs, whereas other cytokine mRNAs tested were unchanged compared with those induced by wt RSV. Because attenuation of RSV typically is accompanied by a reduction in immunogenicity, expression of IFN-[Gamma] by an rRSV represents a method of attenuation in which immumogenicity can be maintained rather than be reduced.

Research was conducted to examine the expression of the adhesion molecules L-selectin (CD62L), leukocyte function-associated antigen-1 and Mac-1 on neutrophils in respiratory syncytial virus (RSV) bronchiolitis. Another objective was to determine whether adhesion molecules such as platelet endothelial cell adhesion molecule (PECAM)-1 and intercellular adhesion molecule may be changed and involved in RSV disease. Results indicate that both L-selectin and PECAM-1 on neutrophils from nasopharyngeal aspirates of RSV-positive infants are downregulated compared with peripheral blood cells.

The 2-5A system is a recognized mechanistic component of the antiviral action of interferon. Interferon-induced 2-5A synthetase generates 2-5A, which, in turn, activates the latent constitutive RNase L that degrades viral RNA. Chemical conjugation of 2-5A to an antisense oligonucleotide can target the 2-SA-dependent RNase L to the antisense-specified RNA and effect its selective destruction. Such a 2-5A-antisense chimera (NIH351) has been developed that targets a consensus sequence within the respiratory syncytial virus (RSV) genomic RNA. NIH351 was 50- to 90-fold more potent against RSV strain A2 than was ribavirin, the presently approved drug for clinical management of RSV infection. It was similarly active against a variety of RSV strains of both A and B subgroups and possessed a cell culture selectivity index comparable to ribavirin. In addition, the anti-RSV activity of NIH351 was shown to be virus-specific and a result of a true antisense effect, because a scrambled nucleotide sequence in the antisense domain of NIH351 caused a significant decrease in antiviral activity. The 2-5A system's RNase L was implicated in the mechanism of action of NIH351 because a congener with a disabled 2-5A moiety was of greatly reduced anti-RSV effectiveness. These findings represent an innovative approach to the control of RSV replication.

A study was conducted on paramyxovirus human respiratory syncytial virus RSV RNA replication and transcription. Short cDNA-encoded analogs of genomic or antigenomic RNA complemented by viral proteins expressed from cotransfected plasmids were used. Results showed that RNA synthesis by RSV is more complex for the negative-strand RNA virus than previously reported and involves at least two more transacting viral factors.

Infectious human respiratory syncytial virus (RSV) was produced by the intracellular coexpression of rive plasmid-borne cDNAs. One cDNA encoded a complete positive-sense version of the RSV genome (corresponding to the replicative intermediate RNA or antigenome, and each of the other four encoded a separate RSV protein, namely, the major nucleocapsid N protein, the nucleocapsid P phosphoprotein, the major polymerase L protein, or the protein from the 5', proximal open reading frame of the M2 mRNA [M2(ORF1)]. RSV was not produced if any of the five plasmids was omitted. The requirement for the M2(ORF1) protein is consistent with its recent identification as a transcription elongation factor and confirms its importance for RSV gene expression. It should thus be possible to introduce defined changes into infectious RSV. This should be useful for basic studies of RSV molecular biology and pathogenesis, in addition, there are immediate applications to the development of live attenuated vaccine strains bearing predetermined defined attenuating mutations.

A combinatorial antibody library wasscreened for Fab fragments for the cross-reactive F glycoprotein of respiratorysyncytial virus (RSV). The antibody library yielded 30 clones of which 28 showed clear reactivity with the F glycoprotein. One of these neutralized a wide range of virus isolates at high efficiency. These human Fab fragments willbe useful for the care and treatment of RSV infections of the lower respiratorytract.

ABBREVIATIONS. RSV, respiratory syncytial virus; FDA, Food and Drug Administration. Progress in the field of passive immunoprophylaxis for protection of high-risk infants and children against respiratory syncytial virus (RSV) infection [...]

ABBREVIATIONS. RSV, respiratory syncytial virus; PIV, parainfluenza virus; SARS, severe acute respiratory syndrome; NVSN, New Vaccine Surveillance Network. Recent years have witnessed a dramatic surge in understanding of viral upper [...]

Respiratory syncytial virus (RSV) is one of the most common causes of lower respiratory infection in children. This infection frequently affects infants and may be severe enough to require hospitalization. There has been little research concerning RSV infection in children over 12 months of age. Over a three-year-period, the incidence, risk factors, clinical features, and outcome of RSV infection were studied in 282 children. All of these children were hospitalized with pneumonia or bronchiolitis and RSV infection was confirmed. Of the total group, 62 children (22 percent) were over 12 months; this represents a higher rate of infection in this age group than indicated by previous studies. This subgroup was then matched for sex, hospital location, and onset of illness with children who were under 12 months of age at the time of RSV infection. Of the 62 older children, 47 (76 percent) had an underlying disease, most often of a pulmonary or cardiac nature. The second most frequently noted underlying problems were gastrointestinal and genetic disorders. Fourteen of the 62 children (almost 25 percent) had a prior history of RSV infection. Of the total group, four children died (three percent), making the mortality rate relatively low. However, three of the four deceased children were over 12 months and had a severe congenital heart condition. It was concluded children over 12 months who have an underlying disease, in particular, pulmonary, cardiac, chronic gastrointestinal or genetic disorders, should be considered a high risk group for RSV infection. Early treatment with the antiviral medication known as ribavirin is recommended for children with RSV infection histories. Parents should be informed of the potential seriousness of RSV infection if their child is in a high risk category. (Consumer Summary produced by Reliance Medical Information, Inc.)

A 13-residue peptide sequence from a respiratory syncitial virus fusion protein is constrained in an alpha-helical conformation by fusing two back-to-back cyclic alpha-turn mimetics. The resulting compound displays potent activity in both a recombinant fusion assay and an RSV antiviral assay, and demonstrates for the first time that back-to-back modular alpha-helix mimetics can produce functional antagonists of important protein-protein interactions.

The M2 mRNA of human respiratory syncytial virus (RSV) contains two overlapping ORFs, encoding the transcription antitermination protein (M2-1) and the 90-aa M2-2 protein of unknown function. Viable recombinant RSV was recovered in which expression of M2-2 was ablated, identifying it as an accessory factor dispensable for growth in vitro. Virus lacking M2-2 grew less efficiently than did the wild-type parent in vitro, with titers that were reduced 1,000-fold during the initial 2-5 days and 10-fold by days 7-8. Compared with wild-type virus, the intracellular accumulation of RNA by M2-2 knockout virus was reduced 3- to 4-fold or more for genomic RNA and increased 2- to 4-fold or more for mRNA. Synthesis of the F and G glycoproteins, the major RSV neutralization and protective antigens, was increased in proportion with that of mRNA. In cells infected with wild-type RSV, mRNA accumulation increased dramatically up to approximately 12-15 hr after infection and then leveled off, whereas accumulation continued to increase in cells infected with the M2-2 knockout viruses. These findings suggest that M2-2 mediates a regulatory 'switch' from transcription to RNA replication, one that provides an initial high level of mRNA synthesis followed by a shift in the RNA synthetic program in favor of genomic RNA for virion assembly. With regard to vaccine development, the M2-2 knockout has a highly desirable phenotype in which virus growth is attenuated while gene expression is concomitantly increased.