Evaluation of the Calu-3 cell line as a model of in vitro respiratory syncytial virus infection

Respiratory syncytial virus (RSV) replication is primarily limited to the upper respiratory tract epithelium and primary, differentiated normal human bronchial epithelial cells (NHBE) have, therefore, been considered a good system for in vitro analysis of lung tissue response to respiratory virus infection and virus–host interactions. However, NHBE cells are expensive, difficult to culture, and vary with the source patient. An alternate approach is to use a continuous cell line that has features of bronchial epithelial cells such as Calu-3, an epithelial cell line derived from human lung adenocarcinoma, as an in vitro model of respiratory virus infection. The results show that Calu-3 fully polarize when grown on permeable supports as liquid-covered cultures. Polarized Calu-3 are susceptible to RSV infection and release infectious virus primarily from the apical surface, consistent with studies in NHBE cells. The data demonstrate that polarized Calu-3 may serve as a useful in vitro model to study host responses to RSV infection.

Equine laryngeal hemiplegia part II: some clinical observations

Some clinical features of laryngeal hemiplegia in 127 horses are described. Possible aetiologic factors were found in only 11% of affected animals. The onset of clinical signs was either sudden or insidious. The majority of cases were presented because of an abnormal respiratory noise made at exercise. Other clinical signs, particularly those usually attributed to laryngopalatal dislocation, were observed in a substantial proportion of affected animals. In all cases surveyed the left arytenoid was affected, although in 3 animals a bilateral laryngeal dysfunction was noted. Thirty of 65 animals examined with a fibreoptic endoscope had other upper respiratory tract abnormalities in addition to abnormal arytenoid movements. Electrocardiographic examination of 45 affected horses did not reveal a significantly higher incidence of abnormalities than that observed in the racing population. The majority of haemograms taken from affected animals were also within normal limits.

Innervation of the equine intrinsic laryngeal muscles

The nerve supply to the intrinsic laryngeal muscles of the horse was studied by gross dissection and by electromyography which was carried out before, during and after section of various intralaryngeal nerve branches. The anatomical relationships and passage of the laryngeal nerves throughout the larynx were defined. Unlike the dog and man there was no evidence of the passage of motor nerve fibres from one side of the larynx to the other.

Roaring in Clydesdales

An endoscopic survey was performed to assess arytenoid cartilage movement during quiet respiration in 48 Clydesdale horses. Physical characteristics which could influence the length of the recurrent laryngeal nerves were also recorded from these horses and the relationship of these characteristics to the presence of abnormal left arytenoid cartilage movements was assessed statistically. Some degree of abnormal arytenoid movement was observed in 50% of the animals over one year of age. No significant correlation between sex, age, estimated weight, height, or neck length could be found although affected animals were, on average, slightly taller, lighter and longer necked.

PneumoniaCheck: A Device for Sampling Lower Airway Aerosols

The pathogens causing pneumonia are difficult to identify because a high quality specimen from the lower lung is difficult to obtain. A new specimen collection device is designed to collect aerosol specimens selectively from the lower lung generated during deep coughing. The PneumoniaCheck device utilizes a separation reservoir and Venturi valve to segregate contents from the upper and lower airways. The device also includes several specially designed features to exclude oral contaminants from the sample and a filter to collect the aerosolized pathogens. Verification testing of PneumoniaCheck demonstrates effective separation of upper airway gas from the lower airway gas (p<0.0001) and exclusion of both liquid and viscous oral material (p<0.0001) from the collection chamber. The filters can collect 99.9997% of virus and bacteria sized particles from the sampled lower lung aerosols. The selective collection of specimens from the lower airway may aid in the diagnosis of specific pathogens causing pneumonia.

Prophylactic treatment with a G glycoprotein monoclonal antibody reduces pulmonary inflammation in respiratory syncytial virus (RSV)-challenged naive and formalin-inactivated RSV-immunized BALB/c mice

We examined whether prophylactically administered anti-respiratory syncytial virus (anti-RSV) G monoclonal antibody (MAb) would decrease the pulmonary inflammation associated with primary RSV infection and formalin-inactivated RSV (FI-RSV)-enhanced disease in mice. MAb 131-2G administration 1 day prior to primary infection reduced the pulmonary inflammatory response and the level of RSV replication. Further, intact or F(ab')(2) forms of MAb 131-2G administered 1 day prior to infection in FI-RSV-vaccinated mice reduced enhanced inflammation and disease. This study shows that an anti-RSV G protein MAb might provide prophylaxis against both primary infection and FI-RSV-associated enhanced disease. It is possible that antibodies with similar reactivities might prevent enhanced disease and improve the safety of nonlive virus vaccines.

Update on SARS research and other possibly zoonotic coronaviruses

The global outbreak of severe acute respiratory syndrome (SARS) in 2003 led to an intense and effective global response that stopped the spread of the disease by July 2003. There was also an intensive and very productive research effort to identify the aetiological agent, characterise the clinical and epidemiological features of the disease, understand the pathogenesis of the disease and the molecular biology of the virus, and design antiviral drugs and vaccines to treat and prevent the disease. In parallel with the SARS research effort there have been continuous improvements in our ability to detect and characterise other novel viruses. The SARS outbreak illustrates the importance of such detection tools in the response to public health threats. Studies since the SARS outbreak suggest that many novel viruses exist in animals and some, but probably not many, will present a risk to humans.

Outbreak of pneumonia associated with emergent human adenovirus serotype 14--Southeast Alaska, 2008

BACKGROUND

In September 2008, an outbreak of pneumonia associated with an emerging human adenovirus (human adenovirus serotype 14 [HAdV-14]) occurred on a rural Southeast Alaska island. Nine patients required hospitalization, and 1 patient died.

METHODS

To investigate the outbreak, pneumonia case patients were matched to control participants on the basis of age, sex, and community of residence. Participants in the investigation and their household contacts were interviewed, and serum samples and respiratory tract specimens were collected. Risk factors were evaluated by means of conditional logistic regression.

RESULTS

Among 32 pneumonia case patients, 21 (65%) had confirmed or probable HAdV-14 infection. None of 32 matched control participants had evidence of HAdV-14 infection (P<.001 for the difference). Factors independently associated with pneumonia included contact with a known HAdV-14-infected case patient (odds ratio [OR], 18.3 [95% confidence interval {CI}, >or=2.0]), current smoking (OR, 6.7 [95% CI, >or=0.9]), and having neither traveled off the island nor attended a large public gathering (OR, 14.7 [95% CI, >or=2.0]). Fourteen (67%) of 21 HAdV-14-positive case patients belonged to a single network of people who socialized and often smoked together and infrequently traveled off the island. HAdV-14 infection occurred in 43% of case-patient household contacts, compared with 5% of control-participant household contacts (P = .005).

CONCLUSIONS

During a community outbreak in Alaska, HAdV-14 appeared to have spread mostly among close contacts and not widely in the community. Demographic characteristics and illness patterns among the case patients were similar to those observed in other recent outbreaks of HAdV-14 infection in the United States.

Viral respiratory infections in hospitalized and community control children in Alaska

Respiratory syncytial virus (RSV) in Alaska Native children from the Yukon Kuskokwim (YK) Delta is associated with a hospitalization rate five times higher than that reported for the general US child population. The role of other viral respiratory pathogens has not been studied in this population. YK Delta children <3 years of age hospitalized with respiratory infections and same aged community control children were prospectively enrolled between October 2005 and September 2007. Polymerase chain reaction detection of viruses was performed on nasopharyngeal samples. Characteristics of hospitalized and asymptomatic control children were analyzed. From October 2005 to September 2007, 440 hospitalized and 425 control children were analyzed. Respiratory viruses were detected in 90% (395) of hospitalized children: 194 (44%) rhinovirus, 131 (30%) adenovirus, 102 (23%) RSV, 77 (18%) para influenza viruses (PIV), 66 (15%) human metapneumovirus (hMPV), 23 (5%) influenza, and 25 (6%) coronavirus. Fifty-two percent (221) of control children had a virus detected, most commonly rhinovirus (33%), and adenovirus (16%). RSV, PIV, hMPV, and influenza were significantly more common in hospitalized cases than control children, but rhinovirus, adenovirus, and coronavirus were not. RSV and hMPV were associated with higher severity of illness. In this study, RSV remains the most important virus associated with respiratory hospitalization, although hMPV and PIV were also common. RSV and hMPV were associated with more severe illness. Rhinovirus and adenovirus were detected in two-thirds of hospitalized children, but their frequent detection in control children made their role in respiratory hospitalization uncertain.

Use of respiratory syncytial virus surveillance data to optimize the timing of immunoprophylaxis

OBJECTIVE

For children in the United States who are at high risk for severe respiratory syncytial virus (RSV) infection, the American Academy of Pediatrics (AAP) recommends administering immunoprophylaxis during the RSV season. We present an approach to using surveillance data to help guide application of AAP recommendations for immunoprophylaxis to local patterns of RSV outbreaks.

METHODS

We analyzed data from laboratories that report consistently to the National Respiratory and Enteric Virus Surveillance System from 1992 to 2007. Local RSV seasons were defined and an immunoprophylaxis schedule was determined by using the median onset dates from each laboratory during 2002-2007. We applied these dates to 10 preceding years of RSV detection data. We compared how well the 5-year median-based method and a fixed date method were able to match the timing of immunoprophylaxis to the RSV season.

RESULTS

Nineteen laboratories met our inclusion criteria and generally experienced only 1 RSV outbreak per season. Five years of data gave similar median onset/offset dates and season duration, as did 10 years and 15 years of data. The 5-year median schedule increased the number of seasons that children were protected at the season onset by 15% compared with a fixed start date of November 1 and identified communities that experienced RSV seasons with extended durations.

CONCLUSIONS

The 5-year median method can be used to characterize timing of RSV seasons and optimally apply the current AAP recommendations for timing of palivizumab prophylaxis to the local community.

Identification of adenoviruses in fecal specimens from wild chimpanzees (Pan trogylodytes schweinfurthii) in western Tanzania

DNA of two distinctive adenoviruses was detected in wild chimpanzees in western Tanzania that showed clinical signs of acute, upper respiratory disease, notably coughing. The amplified sequences from part of the capsid hexon gene suggests that one virus is a novel adenovirus serotype candidate and the other virus is a species C adenovirus most closely related to recent isolates from captive chimpanzees in the United States, Simian AdV 37 with 86% nucleic acid identity and Simian AdV 40 with 95% nucleic acid identity, respectively. The species C adenovirus sequences suggest possible recombination with a human adenovirus. The source of these viruses and disease association is not known.

Potent high-affinity antibodies for treatment and prophylaxis of respiratory syncytial virus derived from B cells of infected patients

Native human Abs represent attractive drug candidates; however, the low frequency of B cells expressing high-quality Abs has posed a barrier to discovery. Using a novel single-cell phenotyping technology, we have overcome this barrier to discover human Abs targeting the conserved but poorly immunogenic central motif of respiratory syncytial virus (RSV) G protein. For the entire cohort of 24 subjects with recent RSV infection, B cells producing Abs meeting these stringent specificity criteria were rare, <10 per million. Several of the newly cloned Abs bind to the RSV G protein central conserved motif with very high affinity (K(d) 1-24 pM). Two of the Abs were characterized in detail and compared with palivizumab, a humanized mAb against the RSV F protein. Relative to palivizumab, the anti-G Abs showed improved viral neutralization potency in vitro and enhanced reduction of infectious virus in a prophylaxis mouse model. Furthermore, in a mouse model for postinfection treatment, both anti-G Abs were significantly more effective than palivizumab at reducing viral load. The combination of activity in mouse models for both prophylaxis and treatment makes these high-affinity human-derived Abs promising candidates for human clinical testing.

Cardiac T2* magnetic resonance for prediction of cardiac complications in thalassemia major

BACKGROUND

The goal of this study was to determine the predictive value of cardiac T2* magnetic resonance for heart failure and arrhythmia in thalassemia major.

METHODS AND RESULTS

We analyzed cardiac and liver T2* magnetic resonance and serum ferritin in 652 thalassemia major patients from 21 UK centers with 1442 magnetic resonance scans. The relative risk for heart failure with cardiac T2* values <10 ms (compared with >10 ms) was 160 (95% confidence interval, 39 to 653). Heart failure occurred in 47% of patients within 1 year of a cardiac T2* <6 ms with a relative risk of 270 (95% confidence interval, 64 to 1129). The area under the receiver-operating characteristic curve for predicting heart failure was significantly greater for cardiac T2* (0.948) than for liver T2* (0.589; P<0.001) or serum ferritin (0.629; P<0.001). Cardiac T2* was <10 ms in 98% of scans in patients who developed heart failure. The relative risk for arrhythmia with cardiac T2* values <20 ms (compared with >20 ms) was 4.6 (95% confidence interval, 2.66 to 7.95). Arrhythmia occurred in 14% of patients within 1 year of a cardiac T2* of <6 ms. The area under the receiver-operating characteristic curve for predicting arrhythmia was significantly greater for cardiac T2* (0.747) than for liver T2* (0.514; P<0.001) or serum ferritin (0.518; P<0.001). The cardiac T2* was <20 ms in 83% of scans in patients who developed arrhythmia.

CONCLUSIONS

Cardiac T2* magnetic resonance identifies patients at high risk of heart failure and arrhythmia from myocardial siderosis in thalassemia major and is superior to serum ferritin and liver iron. Using cardiac T2* for the early identification and treatment of patients at risk is a logical means of reducing the high burden of cardiac mortality in myocardial siderosis. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00520559.

Therapeutic monoclonal antibody treatment targeting respiratory syncytial virus (RSV) G protein mediates viral clearance and reduces the pathogenesis of RSV infection in BALB/c mice

Because the G protein of respiratory syncytial virus (RSV) has a CX3C chemokine motif that has been associated with the ability of RSV G protein to modulate the virus-induced host immune response, we examined whether therapeutic treatment with an anti-RSV G monoclonal antibody (mAb), 131-2G, that blocks the CX3C-associated activity of RSV G protein might decrease the pulmonary inflammation associated with infection in BALB/c mice. The results show that treatment with mAb 131-2G on day 3 after RSV infection reduces both inflammation and RSV titer in the lungs. Later administration of anti-RSV G mAb (day 5 after RSV infection) effectively reduced the viral titer but had a minimal effect on pulmonary inflammation. This study suggests that an anti-RSV G mAb might be an effective antiviral, either alone or in combination with anti-RSV F protein neutralizing antibodies, for decreasing the virus-induced host response to infection and improve treatment outcome.

Application of proteomics methods for pathogen discovery

Proteomics have been used widely to study proteins in complex materials such as cells, body fluids, tissues, and organisms. Application of advance proteomic techniques for the characterization of disease-specific proteins may provide information for the detection of potential infectious agents. In this report, two proteomics techniques, a two-dimensional differential gel electrophoresis (2D-DIGE) and a one-dimensional gel electrophoresis and one-dimensional liquid chromatography coupled with mass spectrometry (GeLC-MS/MS), were applied for investigating viral proteins from cultured cells inoculated with a clinical sample. The 2D-DIGE method identified five viral proteins of vaccinia virus that are only present in infected cells, these results are in agreement with findings determined by genome based methods. The GeLC-MS/MS method identified eight vaccinia virus proteins out of 428 proteins detected in the sample. These results demonstrate that proteomic techniques can be used effectively for the detection of infectious agents. Given that the methods are capable of applying to proteins without a prior knowledge of the pathogen present, proteomics has a potential of being developed as a molecular tool for pathogen discovery, and disease diagnosis of emerging infectious diseases and for bioterrorism defense.

Outbreak of severe respiratory disease associated with emergent human adenovirus serotype 14 at a US air force training facility in 2007

BACKGROUND

In 2007, a US Air Force training facility reported a cluster of severe respiratory illnesses associated with a rare human adenovirus (Ad) serotype, Ad14. We investigated this outbreak to better understand its epidemiology, clinical spectrum, and associated risk factors.

METHODS

Data were collected from ongoing febrile respiratory illness (FRI) surveillance and from a retrospective cohort investigation. Because an Ad7 vaccine is in development, Ad7 antibody titers in pretraining serum samples from trainees with mild and those with severe Ad14 illness were compared.

RESULTS

During 2007, an estimated 551 (48%) of 1147 trainees with FRI were infected with Ad14; 23 were hospitalized with pneumonia, 4 required admission to an intensive care unit, and 1 died. Among cohort members (n = 173), the Ad14 infection rate was high (50%). Of those infected, 40% experienced FRI. No cohort members were hospitalized. Male sex (risk ratio [RR], 4.7 [95% confidence interval {CI}, 2.2-10.1]) and an ill close contact (RR, 1.6 [95% CI, 1.2-2.2]) were associated with infection. Preexisting Ad7 neutralizing antibodies were found in 7 (37%) of 19 Ad14-positive trainees with mild illness but in 0 of 16 trainees with Ad14 pneumonia (P = .007).

CONCLUSIONS

Emergence of Ad14, a rare Ad serotype, caused a protracted outbreak of respiratory illness among military recruits. Most infected recruits experienced FRI or milder illnesses. Some required hospitalization, and 1 died. Natural Ad7 infection may protect against severe Ad14 illness.

Detection of novel SARS-like and other coronaviruses in bats from Kenya

Diverse coronaviruses have been identified in bats from several continents but not from Africa. We identified group 1 and 2 coronaviruses in bats in Kenya, including SARS-related coronaviruses. The sequence diversity suggests that bats are well-established reservoirs for and likely sources of coronaviruses for many species, including humans.

Treatment with respiratory syncytial virus G glycoprotein monoclonal antibody or F(ab')2 components mediates reduced pulmonary inflammation in mice

Therapeutic treatment with a non-neutralizing monoclonal antibody (mAb) (131-2G) specific to respiratory syncytial virus (RSV) G glycoprotein mediates virus clearance and decreases leukocyte trafficking and interferon gamma (IFN-gamma) production in the lungs of RSV-infected mice. Its F(ab')(2) component only mediates decreased leukocyte trafficking and IFN-gamma production without reducing virus replication. Thus, this mAb has two independent actions that could facilitate treatment and/or prevention of RSV infection by reducing both virus replication and virus-induced pulmonary inflammation.

Novel human rhinoviruses and exacerbation of asthma in children

To determine links between human rhinoviruses (HRV) and asthma, we used data from a case–control study, March 2003–February 2004, among children with asthma. Molecular characterization identified several likely new HRVs and showed that association with asthma exacerbations was largely driven by HRV-A and a phylogenetically distinct clade of 8 strains, genogroup C.

Broadening of neutralization activity to directly block a dominant antibody-driven SARS-coronavirus evolution pathway

Phylogenetic analyses have provided strong evidence that amino acid changes in spike (S) protein of animal and human SARS coronaviruses (SARS-CoVs) during and between two zoonotic transfers (2002/03 and 2003/04) are the result of positive selection. While several studies support that some amino acid changes between animal and human viruses are the result of inter-species adaptation, the role of neutralizing antibodies (nAbs) in driving SARS-CoV evolution, particularly during intra-species transmission, is unknown. A detailed examination of SARS-CoV infected animal and human convalescent sera could provide evidence of nAb pressure which, if found, may lead to strategies to effectively block virus evolution pathways by broadening the activity of nAbs. Here we show, by focusing on a dominant neutralization epitope, that contemporaneous- and cross-strain nAb responses against SARS-CoV spike protein exist during natural infection. In vitro immune pressure on this epitope using 2002/03 strain-specific nAb 80R recapitulated a dominant escape mutation that was present in all 2003/04 animal and human viruses. Strategies to block this nAb escape/naturally occurring evolution pathway by generating broad nAbs (BnAbs) with activity against 80R escape mutants and both 2002/03 and 2003/04 strains were explored. Structure-based amino acid changes in an activation-induced cytidine deaminase (AID) “hot spot” in a light chain CDR (complementarity determining region) alone, introduced through shuffling of naturally occurring non-immune human VL chain repertoire or by targeted mutagenesis, were successful in generating these BnAbs. These results demonstrate that nAb-mediated immune pressure is likely a driving force for positive selection during intra-species transmission of SARS-CoV. Somatic hypermutation (SHM) of a single VL CDR can markedly broaden the activity of a strain-specific nAb. The strategies investigated in this study, in particular the use of structural information in combination of chain-shuffling as well as hot-spot CDR mutagenesis, can be exploited to broaden neutralization activity, to improve anti-viral nAb therapies, and directly manipulate virus evolution.

The SARS-CoV caused a worldwide epidemic of SARS in 2002/03 and was responsible for this zoonotic infectious disease. The role of neutralizing antibody (nAb) mediated immune pressure in the evolution of SARS-CoV during the 2002/03 outbreak and a second 2003/04 zoonotic transmission is unknown. Here we demonstrate nAb responses elicited during natural infection clearly have strain-specific components which could have been the driving force for virus evolution in spike protein during intra-species transmission. In vitro immune pressure using 2002/03 strain-specific nAb 80R recapitulate a dominant escape mutation that was present in all 2003/04 animal and human viruses. We investigated how to generate a single broad nAb (BnAb) with activity against various natural viral variants of the 2002/03 and 2003/04 outbreaks as well as nAb escape mutants. Remarkably, amino acid changes in an activation-induced cytidine deaminase (AID) “hot spot” of somatic hypermutation and localized to a single VL CDR were successful in generating BnAbs. These results provide an effective strategy for generating BnAbs that should be generally useful for improving immune based anti-viral therapies as well as providing a foundation to directly manipulate virus evolution by blocking escape pathways.

Mumps epidemiology and immunity: the anatomy of a modern epidemic

The success of the measles, mumps, and rubella 2-dose vaccination program led public health officials in 1998 to set a goal to eliminate endemic transmission of mumps virus by 2010 in the United States. The large outbreak of mumps in the spring of 2006 has led public health officials to re-evaluate this goal and to recognize that the transmission and epidemiology of mumps in highly vaccinated populations may be different than anticipated. During 2006, a total of 6584 confirmed and probable cases of mumps were reported to the Centers for Disease Control and Prevention and most of these, 5865, occurred between January 1 and July 31. The peak of the outbreak was in April and seemed to be focused on college campuses in 9 midwestern states with Iowa having the highest attack rate. College campuses with mumps outbreaks included ones with 77% to 97% of students having had 2 doses of a mumps vaccine. Diagnosing mumps proved to be problematic in vaccinated persons (ie, laboratory tests seemed to be insensitive and some apparent mumps cases had mild nonclassic illness). The outbreak demonstrated that mumps can sometimes transmit efficiently in highly vaccinated populations and the clinical and laboratory diagnosis of mumps in vaccinated persons is more difficult than in naive persons. The reason for this mumps outbreak is not clear but probably results from multiple factors contributing to an overall increase in susceptibility and/or transmission.

Genetic and phenotypic differences between isolates of Haemonchus contortus in Australia

We believe this study is the first to consider the genetic and phenotypic divergence between isolates of Haemonchus contortus in Australia. Microsatellite markers have been used to investigate genetic divergence, whilst phenotypic divergence has been considered through individual worm morphology, isolate life history traits and the effect of isolates upon the host. The results are discussed in the context of the likely introduction of H. contortus to Australia, its recent isolation, and the characteristics of sheep and goat farming which might act to either isolate or distribute parasites. We conclude that there is significant observable genetic divergence between isolates of H. contortus in Australia. The divergence may have been under-estimated in this study due to a variety of factors. Phenotypic divergence is also observed, and potentially has significant implications for both economic losses due to haemonchosis on individual properties and for decisions regarding the regulation of stock movements in Australia.