Search tips
Search criteria

Results 1-11 (11)

Clipboard (0)

Select a Filter Below

Year of Publication
Document Types
1.  Soluble Major Histocompatibility Complex Class I-Related Chain B Molecules Are Increased and Correlate With Clinical Outcomes During Rhinovirus Infection in Healthy Subjects 
Chest  2014;146(1):32-40.
Surface major histocompatibility complex class I-related chain (MIC) A and B molecules are increased by IL-15 and have a role in the activation of natural killer group 2 member D-positive natural killer and CD8 T cells. MICA and MICB also exist in soluble forms (sMICA and sMICB). Rhinoviruses (RVs) are the major cause of asthma exacerbations, and IL-15 levels are decreased in the airways of subjects with asthma. The role of MIC molecules in immune responses in the lung has not been studied. Here, we determine the relationship between MICA and MICB and RV infection in vitro in respiratory epithelial cells and in vivo in healthy subjects and subjects with asthma.
Surface MICA and MICB, as well as sMICA and sMICB, in respiratory epithelial cells were measured in vitro in response to RV infection and exposure to IL-15. Levels of sMICA and sMICB in serum, sputum, and BAL were measured and correlated with blood and bronchoalveolar immune cells in healthy subjects and subjects with asthma before and during RV infection.
RV increased MICA and MICB in vitro in epithelial cells. Exogenous IL-15 upregulated sMICB levels in RV-infected epithelial cells. Levels of sMICB molecules in serum were increased in healthy subjects compared with subjects with stable asthma. Following RV infection, airway levels of sMIC are upregulated, and there are positive correlations between sputum MICB levels and the percentage of bronchoalveolar natural killer cells in healthy subjects but not subjects with asthma.
RV infection induces MIC molecules in respiratory epithelial cells in vitro and in vivo. Induction of MICB molecules is impaired in subjects with asthma, suggesting these molecules may have a role in the antiviral immune response to RV infections.
PMCID: PMC4077410  PMID: 24556715
2.  Airway Inflammation and Illness Severity in Response to Experimental Rhinovirus Infection in Asthma 
Chest  2014;145(6):1219-1229.
The nature of bronchial mucosal inflammation and its physiologic and clinical significance in rhinovirus-induced asthma exacerbations is unclear. We investigated bronchial mucosal inflammatory response and its association with physiologic and clinical outcomes in an experimental model of rhinovirus-induced asthma exacerbations.
We used immunohistochemistry methods to detect phenotypes of inflammatory cells infiltrating the bronchial mucosa before and after experimental rhinovirus infection in 10 subjects with asthma and 15 normal subjects.
Compared with baseline, rhinovirus infection significantly increased the number of epithelial (P = .005) and subepithelial (P = .017) neutrophils in subjects with asthma only and subepithelial CD68+ macrophages in both subjects with asthma (P = .009) and normal subjects (P = .018) but more so in those with asthma (P = .021). Numbers of CD45+, CD68+, and CD20+ cells; neutrophils; and eosinophils at day 4 postinfection were positively associated with virus load (r = 0.50-0.72, P = .016-0.03). At acute infection in subjects with asthma, CD4+ cells correlated with chest symptom scores (r = 0.69, P = .029), the fall in the 10% fall in FEV1 (PC10) correlated with neutrophils (r = −0.89, P = .029), the PC10 correlated inversely with CD4+ (r = −0.67, P = .023) and CD8+ cells (r = −0.65, P = .03), the 20% fall in FEV1 was inversely associated with CD20+ cells (r = −0.65, P = .03), and higher epithelial CD8+ cell counts were significantly associated with a greater maximum fall in FEV1 (r = −0.72, P = .03), whereas higher subepithelial mast cell counts were significantly associated with a lower maximum percent fall in peak expiratory flow (r = 0.8, P = .024).
In subjects with asthma, rhinovirus infection induces bronchial mucosal neutrophilia and more severe monocyte/macrophage infiltration than in normal subjects. Airway neutrophils, eosinophils, and T and B lymphocytes during infection are related to virus load and physiologic and clinical severity, whereas mast cells are related to greater lung function.
PMCID: PMC4042510  PMID: 24457412
3.  Cross-Serotype Immunity Induced by Immunization with a Conserved Rhinovirus Capsid Protein 
PLoS Pathogens  2013;9(9):e1003669.
Human rhinovirus (RV) infections are the principle cause of common colds and precipitate asthma and COPD exacerbations. There is currently no RV vaccine, largely due to the existence of ∼150 strains. We aimed to define highly conserved areas of the RV proteome and test their usefulness as candidate antigens for a broadly cross-reactive vaccine, using a mouse infection model. Regions of the VP0 (VP4+VP2) capsid protein were identified as having high homology across RVs. Immunization with a recombinant VP0 combined with a Th1 promoting adjuvant induced systemic, antigen specific, cross-serotype, cellular and humoral immune responses. Similar cross-reactive responses were observed in the lungs of immunized mice after infection with heterologous RV strains. Immunization enhanced the generation of heterosubtypic neutralizing antibodies and lung memory T cells, and caused more rapid virus clearance. Conserved domains of the RV capsid therefore induce cross-reactive immune responses and represent candidates for a subunit RV vaccine.
Author Summary
Human rhinovirus infections cause the majority of common colds as well as asthma and chronic obstructive pulmonary disease (COPD) exacerbations. The disease burden attributable to rhinoviruses is therefore huge. Despite this and the fact that human rhinoviruses were discovered over 50 years ago, there are currently no specific antiviral therapies or vaccine available. The lack of a rhinovirus vaccine can at least in part be attributed to the fact that rhinoviruses like other pathogens have high variability in surface antibody binding regions, resulting in >100 serotypically distinct strains. We have defined areas of the rhinovirus polyprotein which are highly conserved across strains and which may therefore induce cross-reactive immune responses capable of providing broader protection. Using a mouse model, we show that immunization with a recombinant rhinovirus capsid protein induces cross-reactive cellular and humoral immune responses. After subsequent infection, immunization enhances both neutralising antibody and lung effector and memory T cell responses, expediting virus clearance. Importantly these effects were evident upon challenge with multiple heterologous rhinovirus serotypes, indicating that immunization with conserved rhinovirus capsid proteins may represent a viable strategy for producing a broadly cross-reactive vaccine.
PMCID: PMC3784482  PMID: 24086140
4.  Rhinovirus Infection Induces Degradation of Antimicrobial Peptides and Secondary Bacterial Infection in Chronic Obstructive Pulmonary Disease 
Rationale: Chronic obstructive pulmonary disease (COPD) exacerbations are associated with virus (mostly rhinovirus) and bacterial infections, but it is not known whether rhinovirus infections precipitate secondary bacterial infections.
Objectives: To investigate relationships between rhinovirus infection and bacterial infection and the role of antimicrobial peptides in COPD exacerbations.
Methods: We infected subjects with moderate COPD and smokers and nonsmokers with normal lung function with rhinovirus. Induced sputum was collected before and repeatedly after rhinovirus infection and virus and bacterial loads measured with quantitative polymerase chain reaction and culture. The antimicrobial peptides secretory leukoprotease inhibitor (SLPI), elafin, pentraxin, LL-37, α-defensins and β-defensin-2, and the protease neutrophil elastase were measured in sputum supernatants.
Measurements and Main Results: After rhinovirus infection, secondary bacterial infection was detected in 60% of subjects with COPD, 9.5% of smokers, and 10% of nonsmokers (P < 0.001). Sputum virus load peaked on Days 5–9 and bacterial load on Day 15. Sputum neutrophil elastase was significantly increased and SLPI and elafin significantly reduced after rhinovirus infection exclusively in subjects with COPD with secondary bacterial infections, and SLPI and elafin levels correlated inversely with bacterial load.
Conclusions: Rhinovirus infections are frequently followed by secondary bacterial infections in COPD and cleavage of the antimicrobial peptides SLPI and elafin by virus-induced neutrophil elastase may precipitate these secondary bacterial infections. Therapy targeting neutrophil elastase or enhancing innate immunity may be useful novel therapies for prevention of secondary bacterial infections in virus-induced COPD exacerbations.
PMCID: PMC3530206  PMID: 23024024
rhinovirus; chronic obstructive pulmonary disease; disease exacerbation; bacteria
5.  Defining critical roles for NF-κB p65 and type I interferon in innate immunity to rhinovirus 
EMBO Molecular Medicine  2012;4(12):1244-1260.
The importance of NF-κB activation and deficient anti-viral interferon induction in the pathogenesis of rhinovirus-induced asthma exacerbations is poorly understood. We provide the first in vivo evidence in man and mouse that rhinovirus infection enhanced bronchial epithelial cell NF-κB p65 nuclear expression, NF-κB p65 DNA binding in lung tissue and NF-κB-regulated airway inflammation. In vitro inhibition of NF-κB reduced rhinovirus-induced pro-inflammatory cytokines but did not affect type I/III interferon induction. Rhinovirus-infected p65-deficient mice exhibited reduced neutrophilic inflammation, yet interferon induction, antiviral responses and virus loads were unaffected, indicating that NF-κB p65 is required for pro-inflammatory responses, but redundant in interferon induction by rhinoviruses in vivo. Conversely, IFNAR1−/− mice exhibited enhanced neutrophilic inflammation with impaired antiviral immunity and increased rhinovirus replication, demonstrating that interferon signalling was critical to antiviral immunity. We thus provide new mechanistic insights into rhinovirus infection and demonstrate the therapeutic potential of targeting NF-κB p65 (to suppress inflammation but preserve anti-viral immunity) and type I IFN signalling (to enhance deficient anti-viral immunity) to treat rhinovirus-induced exacerbations of airway diseases.
PMCID: PMC3531601  PMID: 23165884
asthma; inflammation; interferon; NF-kappaB; rhinovirus
6.  Correction: The Role of IL-15 Deficiency in the Pathogenesis of Virus-Induced Asthma Exacerbations 
PLoS Pathogens  2012;8(4):10.1371/annotation/43a4a197-1739-4561-8b8d-b13cd6d7009f.
PMCID: PMC3321056
7.  RSV-Induced Bronchial Epithelial Cell PD-L1 Expression Inhibits CD8+ T Cell Nonspecific Antiviral Activity 
Respiratory syncytial virus (RSV) is a major cause of bronchiolitis in infants. It is also responsible for high morbidity and mortality in the elderly. Programmed death ligands (PD-Ls) on antigen-presenting cells interact with receptors on T cells to regulate immune responses. The programmed death receptor-ligand 1/programmed death receptor 1 (PD-L1-PD-1) pathway is inhibitory in chronic viral infections, but its role in acute viral infections is unclear. We hypothesized that bronchial epithelial cell (BEC) expression of PD-Ls would inhibit local effector CD8+ T cell function. We report that RSV infection of primary human BECs strongly induces PD-L1 expression. In a co-culture system of BECs with purified CD8+ T cells, we demonstrated that RSV-infected BECs increased CD8+ T cell activation, proliferation, and antiviral function. Blocking PD-L1 on RSV-infected BECs co-cultured with CD8+ T cells enhanced CD8+ T cell IFN-γ, IL-2, and granzyme B production. It also decreased the virus load of the BECs. Based on our findings, we believe therapeutic strategies that target the PD-L1-PD-1 pathway might increase antiviral immune responses to RSV and other acute virus infections.
PMCID: PMC3086441  PMID: 21148500
8.  Experimental Rhinovirus Infection as a Human Model of Chronic Obstructive Pulmonary Disease Exacerbation 
Rationale: Respiratory virus infections are associated with chronic obstructive pulmonary disease (COPD) exacerbations, but a causative relationship has not been proven. Studies of naturally occurring exacerbations are difficult and the mechanisms linking virus infection to exacerbations are poorly understood. We hypothesized that experimental rhinovirus infection in subjects with COPD would reproduce the features of naturally occurring COPD exacerbations and is a valid model of COPD exacerbations.
Objectives: To evaluate experimental rhinovirus infection as a model of COPD exacerbation and to investigate the mechanisms of virus-induced exacerbations.
Methods: We used experimental rhinovirus infection in 13 subjects with COPD and 13 nonobstructed control subjects to investigate clinical, physiologic, pathologic, and antiviral responses and relationships between virus load and these outcomes.
Measurements and Main Results: Clinical data; inflammatory mediators in blood, sputum, and bronchoalveolar lavage; and viral load in nasal lavage, sputum, and bronchoalveolar lavage were measured at baseline and after infection with rhinovirus 16. After rhinovirus infection subjects with COPD developed lower respiratory symptoms, airflow obstruction, and systemic and airway inflammation that were greater and more prolonged compared with the control group. Neutrophil markers in sputum related to clinical outcomes and virus load correlated with inflammatory markers. Virus load was higher and IFN production by bronchoalveolar lavage cells was impaired in the subjects with COPD.
Conclusions: We have developed a new model of COPD exacerbation that strongly supports a causal relationship between rhinovirus infection and COPD exacerbations. Impaired IFN production and neutrophilic inflammation may be important mechanisms in virus-induced COPD exacerbations.
PMCID: PMC3081284  PMID: 20889904
disease exacerbation; respiratory tract infections; COPD; rhinovirus
9.  The Role of IL-15 Deficiency in the Pathogenesis of Virus-Induced Asthma Exacerbations 
PLoS Pathogens  2011;7(7):e1002114.
Rhinovirus infections are the major cause of asthma exacerbations. We hypothesised that IL-15, a cytokine implicated in innate and acquired antiviral immunity, may be deficient in asthma and important in the pathogenesis of asthma exacerbations. We investigated regulation of IL-15 induction by rhinovirus in human macrophages in vitro, IL-15 levels in bronchoalveolar lavage (BAL) fluid and IL-15 induction by rhinovirus in BAL macrophages from asthmatic and control subjects, and related these to outcomes of infection in vivo. Rhinovirus induced IL-15 in macrophages was replication-, NF-κB- and α/β interferon-dependent. BAL macrophage IL-15 induction by rhinovirus was impaired in asthmatics and inversely related to lower respiratory symptom severity during experimental rhinovirus infection. IL-15 levels in BAL fluid were also decreased in asthmatics and inversely related with airway hyperresponsiveness and with virus load during in vivo rhinovirus infection. Deficient IL-15 production in asthma may be important in the pathogenesis of asthma exacerbations.
Author Summary
We previously reported deficiency in interferon production in asthma, which correlated with disease severity and viral load during experimental rhinovirus infection. Here we show that macrophages produce IL-15 upon rhinovirus infection and that IFN-β plays an important role in IL-15 production. In asthmatic subjects, there is a deficiency in rhinovirus-induced production of IL-15 by macrophages, which indicates immunodeficiency in asthma is surprisingly broad, also involving IL-15, an important cytokine that bridges innate and acquired immunity. These results show that IFN-β therapy in asthma exacerbations could be effective not only due to direct anti-viral effects of IFN-β, but also by inducing IL-15 production. We also show induction of IFN-β and IL-15 to be NF-kB dependent, an important finding which has implications for NF-kB inhibitor drug development programmes as these drugs have potential to worsen rather than improve asthma exacerbation severity, by further enhancing deficiencies of IL-15 and IFN-β. This study investigating the role of IL-15 in rhinovirus infection and asthma has also major implications in other diseases, for example pandemic influenza, where asthma is a major risk factor for severe disease and death, and COPD and cystic fibrosis where IFN-β deficiency is also present.
PMCID: PMC3136447  PMID: 21779162
10.  Association of bacteria and viruses with wheezy episodes in young children: prospective birth cohort study 
Objective To study the association between wheezy symptoms in young children and the presence of bacteria in the airways.
Design Birth cohort study.
Setting Clinical research unit in Copenhagen.
Participants Children of asthmatic mothers, from age 4 weeks to 3 years, with planned visits and acute admissions to the research clinic.
Main outcome measure Frequency of bacteria and virus carriage in airway aspirates during wheezy episodes and at planned visits without respiratory symptoms.
Results 984 samples (361 children) were analysed for bacteria, 844 (299 children) for viruses, and 696 (277 children) for both viruses and bacteria. Wheezy episodes were associated with both bacterial infection (odds ratio 2.9, 95% confidence interval 1.9 to 4.3; P<0.001) and virus infection (2.8, 1.7 to 4.4; P<0.001). The associations of bacteria and viruses were independent of each other.
Conclusion Acute wheezy episodes in young children were significantly associated with bacterial infections similar to but independent of the association with virus infections.
PMCID: PMC2950260  PMID: 20921080
11.  An experimental model of rhinovirus induced chronic obstructive pulmonary disease exacerbations: a pilot study 
Respiratory Research  2006;7(1):116.
Acute exacerbations of COPD are a major cause of morbidity, mortality and hospitalisation. Respiratory viruses are associated with the majority of exacerbations but a causal relationship has not been demonstrated and the mechanisms of virus-induced exacerbations are poorly understood. Development of a human experimental model would provide evidence of causation and would greatly facilitate understanding mechanisms, but no such model exists.
We aimed to evaluate the feasibility of developing an experimental model of rhinovirus induced COPD exacerbations and to assess safety of rhinovirus infection in COPD patients. We carried out a pilot virus dose escalating study to assess the minimum dose of rhinovirus 16 required to induce experimental rhinovirus infection in subjects with COPD (GOLD stage II). Outcomes were assessed by monitoring of upper and lower respiratory tract symptoms, lung function, and virus replication and inflammatory responses in nasal lavage.
All 4 subjects developed symptomatic colds with the lowest dose of virus tested, associated with evidence of viral replication and increased pro-inflammatory cytokines in nasal lavage. These were accompanied by significant increases in lower respiratory tract symptoms and reductions in PEF and FEV1. There were no severe exacerbations or other adverse events.
Low dose experimental rhinovirus infection in patients with COPD induces symptoms and lung function changes typical of an acute exacerbation of COPD, appears safe, and provides preliminary evidence of causation.
PMCID: PMC1578567  PMID: 16956406

Results 1-11 (11)