Discover the most talked about and latest scientific content & concepts.

Concept: Rhinovirus


Most isolates of human rhinovirus, the common cold virus, replicate more robustly at the cool temperatures found in the nasal cavity (33-35 °C) than at core body temperature (37 °C). To gain insight into the mechanism of temperature-dependent growth, we compared the transcriptional response of primary mouse airway epithelial cells infected with rhinovirus at 33 °C vs. 37 °C. Mouse airway cells infected with mouse-adapted rhinovirus 1B exhibited a striking enrichment in expression of antiviral defense response genes at 37 °C relative to 33 °C, which correlated with significantly higher expression levels of type I and type III IFN genes and IFN-stimulated genes (ISGs) at 37 °C. Temperature-dependent IFN induction in response to rhinovirus was dependent on the MAVS protein, a key signaling adaptor of the RIG-I-like receptors (RLRs). Stimulation of primary airway cells with the synthetic RLR ligand poly I:C led to greater IFN induction at 37 °C relative to 33 °C at early time points poststimulation and to a sustained increase in the induction of ISGs at 37 °C relative to 33 °C. Recombinant type I IFN also stimulated more robust induction of ISGs at 37 °C than at 33 °C. Genetic deficiency of MAVS or the type I IFN receptor in infected airway cells permitted higher levels of viral replication, particularly at 37 °C, and partially rescued the temperature-dependent growth phenotype. These findings demonstrate that in mouse airway cells, rhinovirus replicates preferentially at nasal cavity temperature due, in part, to a less efficient antiviral defense response of infected cells at cool temperature.

Concepts: Protein, Gene, Antiviral drug, Interferon, Influenza, Common cold, Rhinovirus, Pleconaril


As the predominant aetiological agent of the common cold, human rhinovirus (HRV) is the leading cause of human infectious disease. Early studies showed that a monovalent formalin-inactivated HRV vaccine can be protective, and virus-neutralizing antibodies (nAb) correlated with protection. However, co-circulation of many HRV types discouraged further vaccine efforts. Here, we test the hypothesis that increasing virus input titres in polyvalent inactivated HRV vaccine may result in broad nAb responses. We show that serum nAb against many rhinovirus types can be induced by polyvalent, inactivated HRVs plus alhydrogel (alum) adjuvant. Using formulations up to 25-valent in mice and 50-valent in rhesus macaques, HRV vaccine immunogenicity was related to sufficient quantity of input antigens, and valency was not a major factor for potency or breadth of the response. Thus, we have generated a vaccine capable of inducing nAb responses to numerous and diverse HRV types.

Concepts: Immune system, Antiviral drug, Influenza, Primate, Rhesus Macaque, Common cold, Rhinovirus, Pleconaril


About 150 human rhinovirus serotypes are responsible for more than 50 % of recurrent upper respiratory infections. Despite having similar 3D structures, some bind members of the low-density lipoprotein receptor family, some ICAM-1, and some use CDHR3 for host cell infection. This is also reflected in the pathways exploited for cellular entry. We found that even rhinovirus serotypes binding the same receptor can travel along different endocytic pathways and release their RNA genome into the cytosol at different locations. How this may account for distinct immune responses elicited by various rhinoviruses and the observed symptoms of the common cold is briefly discussed.

Concepts: Immune system, Asthma, Influenza, Otitis media, Fatigue, Upper respiratory tract infection, Common cold, Rhinovirus


We describe a lethal respiratory outbreak among wild chimpanzees in Uganda in 2013 for which molecular and epidemiologic analyses implicate human rhinovirus C as the cause. Postmortem samples from an infant chimpanzee yielded near-complete genome sequences throughout the respiratory tract; other pathogens were absent. Epidemiologic modeling estimated the basic reproductive number (R0) for the epidemic as 1.83, consistent with the common cold in humans. Genotyping of 41 chimpanzees and examination of 24 published chimpanzee genomes from subspecies across Africa showed universal homozygosity for the cadherin-related family member 3 CDHR3-Y529 allele, which increases risk for rhinovirus C infection and asthma in human children. These results indicate that chimpanzees exhibit a species-wide genetic susceptibility to rhinovirus C and that this virus, heretofore considered a uniquely human pathogen, can cross primate species barriers and threatens wild apes. We advocate engineering interventions and prevention strategies for rhinovirus infections for both humans and wild apes.

Concepts: Epidemiology, Human, Primate, Hominidae, Chimpanzee, Gorilla, Common cold, Rhinovirus



Our main objective was to evaluate the ability of cranberry phytochemicals to modify immunity, specifically gammadelta-T cell proliferation, after daily consumption of a cranberry beverage, and its effect on health outcomes related to cold and influenza symptoms.

Concepts: Bacteria, Influenza, Fatigue, Polyphenol antioxidant, Common cold, Influenza-like illness, Rhinovirus, Nasal congestion


Most strains of rhinovirus (RV), the common cold virus, replicate better at cool temperatures found in the nasal cavity (33-35 °C) than at lung temperature (37 °C). Recent studies found that although 37 °C temperature suppressed RV growth largely by engaging the type 1 IFN response in infected epithelial cells, a significant temperature dependence to viral replication remained in cells devoid of IFN induction or signaling. To gain insight into IFN-independent mechanisms limiting RV replication at 37 °C, we studied RV infection in human bronchial epithelial cells and H1-HeLa cells. During the single replication cycle, RV exhibited temperature-dependent replication in both cell types in the absence of IFN induction. At 37 °C, earlier signs of apoptosis in RV-infected cells were accompanied by reduced virus production. Furthermore, apoptosis of epithelial cells was enhanced at 37 °C in response to diverse stimuli. Dynamic mathematical modeling and B cell lymphoma 2 (BCL2) overexpression revealed that temperature-dependent host cell death could partially account for the temperature-dependent growth observed during RV amplification, but also suggested additional mechanisms of virus control. In search of a redundant antiviral pathway, we identified a role for the RNA-degrading enzyme RNAseL. Simultaneous antagonism of apoptosis and RNAseL increased viral replication and dramatically reduced temperature dependence. These findings reveal two IFN-independent mechanisms active in innate defense against RV, and demonstrate that even in the absence of IFNs, temperature-dependent RV amplification is largely a result of host cell antiviral restriction mechanisms operating more effectively at 37 °C than at 33 °C.

Concepts: Asthma, Antiviral drug, Interferon, Influenza, Common cold, Rhinovirus, Nasal congestion, Pleconaril


BACKGROUND: It has long been believed that antibiotics have no role in the treatment of common colds yet they are often prescribed in the belief that they may prevent secondary bacterial infections. OBJECTIVES: To determine the efficacy of antibiotics compared with placebo for reducing general and specific nasopharyngeal symptoms of acute upper respiratory tract infections (URTIs) (common colds).To determine if antibiotics have any influence on the outcomes for acute purulent rhinitis and acute clear rhinitis lasting less than 10 days before the intervention.To determine whether there are significant adverse outcomes associated with antibiotic therapy for participants with a clinical diagnosis of acute URTI or acute purulent rhinitis. SEARCH METHODS: For this 2013 update we searched CENTRAL 2013, Issue 1, MEDLINE (March 2005 to February week 2, 2013), EMBASE (January 2010 to February 2013), CINAHL (2005 to February 2013), LILACS (2005 to February 2013) and Biosis Previews (2005 to February 2013). SELECTION CRITERIA: Randomised controlled trials (RCTs) comparing any antibiotic therapy against placebo in people with symptoms of acute upper respiratory tract infection for less than seven days, or acute purulent rhinitis less than 10 days in duration. DATA COLLECTION AND ANALYSIS: Both review authors independently assessed trial quality and extracted data. MAIN RESULTS: This updated review included 11 studies. Six studies contributed to one or more analyses related to the common cold, with up to 1047 participants. Five studies contributed to one or more analyses relating to purulent rhinitis, with up to 791 participants. One study contributed only to data on adverse events and one met the inclusion criteria but reported only summary statistics without providing any numerical data that could be included in the meta-analyses. Interpretation of the combined data is limited because some studies included only children, or only adults, or only males; a wide range of antibiotics were used and outcomes were measured in different ways. There was a moderate risk of bias because of unreported methods details or because an unknown number of participants were likely to have chest or sinus infections.Participants receiving antibiotics for the common cold did no better in terms of lack of cure or persistence of symptoms than those on placebo (risk ratio (RR) 0.95, 95% confidence interval (CI) 0.59 to 1.51, (random-effects)), based on a pooled analysis of six trials with a total of 1047 participants. The RR of adverse effects in the antibiotic group was 1.8, 95% CI 1.01 to 3.21, (random-effects). Adult participants had a significantly greater risk of adverse effects with antibiotics than with placebo (RR 2.62, 95% CI 1.32 to 5.18) (random-effects) while there was no greater risk in children (RR 0.91, 95% CI 0.51 to 1.63).The pooled RR for persisting acute purulent rhinitis with antibiotics compared to placebo was 0.73 (95% CI 0.47 to 1.13) (random-effects), based on four studies with 723 participants. There was an increase in adverse effects in the studies of antibiotics for acute purulent rhinitis (RR 1.46, 95% CI 1.10 to 1.94). AUTHORS' CONCLUSIONS: There is no evidence of benefit from antibiotics for the common cold or for persisting acute purulent rhinitis in children or adults. There is evidence that antibiotics cause significant adverse effects in adults when given for the common cold and in all ages when given for acute purulent rhinitis. Routine use of antibiotics for these conditions is not recommended.

Concepts: Antibiotic resistance, Antiviral drug, Influenza, Respiratory system, Antibiotic, Upper respiratory tract infection, Common cold, Rhinovirus


MDA5 is a cytosolic sensor of double-stranded RNA (ds)RNA including viral byproducts and intermediates. We studied a child with life-threatening, recurrent respiratory tract infections, caused by viruses including human rhinovirus (HRV), influenza virus, and respiratory syncytial virus (RSV). We identified in her a homozygous missense mutation in IFIH1 that encodes MDA5. Mutant MDA5 was expressed but did not recognize the synthetic MDA5 agonist/(ds)RNA mimic polyinosinic-polycytidylic acid. When overexpressed, mutant MDA5 failed to drive luciferase activity from the IFNB1 promoter or promoters containing ISRE or NF-κB sequence motifs. In respiratory epithelial cells or fibroblasts, wild-type but not knockdown of MDA5 restricted HRV infection while increasing IFN-stimulated gene expression and IFN-β/λ. However, wild-type MDA5 did not restrict influenza virus or RSV replication. Moreover, nasal epithelial cells from the patient, or fibroblasts gene-edited to express mutant MDA5, showed increased replication of HRV but not influenza or RSV. Thus, human MDA5 deficiency is a novel inborn error of innate and/or intrinsic immunity that causes impaired (ds)RNA sensing, reduced IFN induction, and susceptibility to the common cold virus.

Concepts: DNA, Gene, Virus, Interferon, Influenza, Human respiratory syncytial virus, Common cold, Rhinovirus


Asthma exacerbations exhibit a consistent annual pattern, closely mirroring the school calendar. Although respiratory viruses-the “common cold” viruses-are implicated as a principal cause, there is little evidence to link viral prevalence to seasonal differences in risk. We jointly fit a common cold transmission model and a model of biological and environmental exacerbation triggers to estimate effects on hospitalization risk. Asthma hospitalization rate, influenza prevalence, and air quality measures are available, but common cold circulation is not; therefore, we generate estimates of viral prevalence using a transmission model. Our deterministic multivirus transmission model includes transmission rates that vary when school is closed. We jointly fit the two models to 7 y of daily asthma hospitalizations in adults and children (66,000 events) in eight metropolitan areas. For children, we find that daily viral prevalence is the strongest predictor of asthma hospitalizations, with transmission reduced by 45% (95% credible interval =41-49%) during school closures. We detect a transient period of nonspecific immunity between infections lasting 19 (17-21) d. For adults, hospitalizations are more variable, with influenza driving wintertime peaks. Neither particulate matter nor ozone was an important predictor, perhaps because of the large geographic area of the populations. The school calendar clearly and predictably drives seasonal variation in common cold prevalence, which results in the “back-to-school” asthma exacerbation pattern seen in children and indirectly contributes to exacerbation risk in adults. This study provides a framework for anticipating the seasonal dynamics of common colds and the associated risks for asthmatics.

Concepts: Immune system, Asthma, Influenza, Chronic obstructive pulmonary disease, Paracetamol, Common cold, Influenza-like illness, Rhinovirus