Recombinant human interferon-gamma as prophylaxis against rhinovirus colds in volunteers

The Dietary Intake of Carrot-Derived Rhamnogalacturonan-I Accelerates and Augments the Innate Immune and Anti-Viral Interferon Response to Rhinovirus Infection and Reduces Duration and Severity of Symptoms in Humans in a Randomized Trial

Acute respiratory infections are an important health concern. Traditionally, polysaccharide-enriched extracts from plants, containing immunomodulatory rhamnogalacturonan-I (RG-1), were used prophylactically. We established the effects of dietary supplementation with carrot-derived RG-I (cRG-I, 0–0.3–1.5 g/day) in 177 healthy individuals (18–65 years) on symptoms following infection with rhinovirus strain 16 (RV16). Primary outcomes were changes in severity and duration of symptoms, and viral load in nasal lavage. Secondary outcomes were changes in innate immune and anti-viral responses, reflected by CXCL10 and CXCL8 levels and cell differentials in nasal lavage. In a nested cohort, exploratory transcriptome analysis was conducted on nasal epithelium. Intake of cRG-I was safe, well-tolerated and accelerated local cellular and humoral innate immune responses induced by RV16 infection, with the strongest effects at 1.5 g/d. At 0.3 g/d, a faster interferon-induced response, induction of the key anti-viral gene EIF2AK2, faster viral clearance, and reduced symptom severity (−20%) and duration (−25%) were observed. Anti-viral responses, viral clearance and symptom scores at 1.5 g/d were in between those of 0 and 0.3 g/d, suggesting a negative feedback loop preventing excessive interferon responses. Dietary intake of cRG-I accelerated innate immune and antiviral responses, and reduced symptoms of an acute respiratory viral infection.

Experimental Antiviral Therapeutic Studies for Human Rhinovirus Infections

Rhinovirus infection is common and usually causes mild, self-limiting upper respiratory tract symptoms. Rhinoviruses can cause exacerbation of chronic respiratory diseases, such as asthma or chronic obstructive pulmonary disease, leading to a significant burden of morbidity and mortality. There has been a great deal of progress in efforts to understand the immunological basis of rhinovirus infection. However, despite a number of in vitro and in vivo attempts, there have been no effective treatments developed. This review article summarises the up to date virological and immunological understanding of these infections. We discuss the challenges researchers face, and key solutions, in their work to investigate potential therapies including in vivo rhinovirus challenge studies. Finally, we explore past and present experimental therapeutic strategies employed in the treatment of rhinovirus infections and highlight promising areas of future work.

Review: The Nose as a Route for Therapy. Part 2 Immunotherapy

The nose provides a route of access to the body for inhalants and fluids. Unsurprisingly it has a strong immune defense system, with involvement of innate (e.g., epithelial barrier, muco- ciliary clearance, nasal secretions with interferons, lysozyme, nitric oxide) and acquired (e.g., secreted immunoglobulins, lymphocytes) arms. The lattice network of dendritic cells surrounding the nostrils allows rapid uptake and sampling of molecules able to negotiate the epithelial barrier. Despite this many respiratory infections, including SARS-CoV2, are initiated through nasal mucosal contact, and the nasal mucosa is a significant "reservoir" for microbes including Streptococcus pneumoniae, Neisseria meningitidis and SARS -CoV-2. This review includes consideration of the augmentation of immune defense by the nasal application of interferons, then the reduction of unnecessary inflammation and infection by alteration of the nasal microbiome. The nasal mucosa and associated lymphoid tissue (nasopharynx-associated lymphoid tissue, NALT) provides an important site for vaccine delivery, with cold-adapted live influenza strains (LAIV), which replicate intranasally, resulting in an immune response without significant clinical symptoms, being the most successful thus far. Finally, the clever intranasal application of antibodies bispecific for allergens and Intercellular Adhesion Molecule 1 (ICAM-1) as a topical treatment for allergic and RV-induced rhinitis is explained.

In vivo experimental models of infection and disease

Human and animal models continue to play a crucial role in research to understand host immunity to rhinovirus (RV) and identify disease mechanisms. Human models have provided direct evidence that RV infection is capable of exacerbating chronic respiratory diseases and identified immunological processes that correlate with clinical disease outcomes. Mice are the most commonly used nonhuman experimental RV infection model. Although semipermissive, under defined experimental conditions sufficient replication occurs to induce host immune responses that recapitulate immunity and disease during human infection. The capacity to use genetically modified mouse strains and drug interventions has shown the mouse model to be an invaluable research tool defining causal relationships between host immunity and disease and supporting development of new treatments. Used in combination the insights achieved from human and animal experimental infection models provide complementary insights into RV biology and yield novel therapeutic options to reduce the burden of RV-induced disease.

Utility of animal and in vivo experimental infection of humans with rhinoviruses in the development of therapeutic agents for viral exacerbations of asthma and chronic obstructive pulmonary disease

There is an association with acute viral infection of the respiratory tract and exacerbations of asthma and chronic obstructive pulmonary disease (COPD). Although these exacerbations are associated with several types of viruses, human rhinoviruses (HRVs) are associated with the vast majority of disease exacerbations. Due to the lack of an animal species that is naturally permissive for HRVs to use as a facile model system, and the limitations associated with animal models of asthma and COPD, studies of controlled experimental infection of humans with HRVs have been used and conducted safely for decades. This review discusses how these experimental infection studies with HRVs have provided a means of understanding the pathophysiology underlying virus-induced exacerbations of asthma and COPD with the goal of developing agents for their prevention and treatment.

Human challenge studies: a review of adequacy of reporting methods and results

Since the 1940s, researchers have purposefully infected healthy adult humans with pathogenic organisms to study how these pathogens cause disease and can be treated and prevented. 'Challenge studies' can be safe, ethical, extremely informative and an efficient use of resources during the clinical development of vaccines, but knowledge of this form of clinical research trial is not widespread. A review of the human challenge literature was performed to determine whether common elements of challenge studies can be identified in the articles published to date. The review demonstrated incomplete reporting of study characteristics deemed necessary for the correct interpretation and application of human challenge study results and for the accurate replication of study methodology. An unofficial extension of the Consolidated Standards of Reporting Trials (CONSORT) statement is proposed.

The human rhinovirus: human-pathological impact, mechanisms of antirhinoviral agents, and strategies for their discovery

As the major etiological agent of the common cold, human rhinoviruses (HRV) cause millions of lost working and school days annually. Moreover, clinical studies proved an association between harmless upper respiratory tract infections and more severe diseases e.g. sinusitis, asthma, and chronic obstructive pulmonary disease. Both the medicinal and socio-economic impact of HRV infections and the lack of antiviral drugs substantiate the need for intensive antiviral research. A common structural feature of the approximately 100 HRV serotypes is the icosahedrally shaped capsid formed by 60 identical copies of viral capsid proteins VP1-4. The capsid protects the single-stranded, positive sense RNA genome of about 7,400 bases in length. Both structural as well as nonstructural proteins produced during the viral life cycle have been identified as potential targets for blocking viral replication at the step of attachment, entry, uncoating, RNA and protein synthesis by synthetic or natural compounds. Moreover, interferon and phytoceuticals were shown to protect host cells. Most of the known inhibitors of HRV replication were discovered as a result of empirical or semi-empirical screening in cell culture. Structure-activity relationship studies are used for hit optimization and lead structure discovery. The increasing structural insight and molecular understanding of viral proteins on the one hand and the advent of innovative computer-assisted technologies on the other hand have facilitated a rationalized access for the discovery of small chemical entities with antirhinoviral (anti-HRV) activity. This review will (i) summarize existing structural knowledge about HRV, (ii) focus on mechanisms of anti-HRV agents from synthetic and natural origin, and (iii) demonstrate strategies for efficient lead structure discovery.

WITHDRAWN: Antivirals for the common cold

BACKGROUND

The common cold is a ubiquitous short and usually mild illness for which preventive and treatment interventions have been under development since the mid-40s. As our understanding of the disease has increased, more experimental antivirals have been developed. This review attempts to draw together experimental evidence of the effects of these compounds.

OBJECTIVES

To identify, assemble, evaluate and (if possible) synthesise the results of published and unpublished randomised controlled trials of the effects of antivirals to prevent or minimise the impact of the common cold.

SEARCH STRATEGY

We searched electronic databases, corresponded with researchers and handsearched the archives of the MRC's Common Cold Unit (CCU).

SELECTION CRITERIA

We included original reports of randomised and quasi-randomised trials assessing the effects of antivirals on volunteers artificially infected and in individuals exposed to colds in the community.

DATA COLLECTION AND ANALYSIS

We included 241 studies assessing the effects of Interferons, interferon-inducers and other antivirals on experimental and naturally occurring common colds, contained in 230 reports. We structured our comparisons by experimental or community setting.

MAIN RESULTS

Although intranasal interferons have high preventive efficacy against experimental colds (protective efficacy 46%, 37% to 54%) and to a lesser extent against natural colds (protective efficacy 24%, 21% to 27%) and are also significantly more effective than placebo in attenuating the course of experimental colds (WMD 15.90, 13.42 to 18.38), their safety profile makes compliance with their use difficult. For example, prolonged prevention of community colds with interferons causes blood-tinged nasal discharge (OR 4.52, 3.78 to 5.41). Dipyridamole (protective efficacy against natural colds 49%, 30% to 62%), ICI 130, 685 (protective efficacy against experimental colds 58%, 35% to 74% ), Impulsin (palmitate) (protective efficacy against natural colds 44%, CI 35% to 52% ) and Pleconaril (protective efficacy against experimental colds 71%, 15% to 90% ) appear to have important antiviral properties and are well-tolerated. The evidence of effectiveness of other compounds in the treatment of experimental or natural colds is sparse.

AUTHORS' CONCLUSIONS

There are no licensed effective antivirals for the common cold. Because prolonged intranasal administration causes a clinical picture which is not distinguishable from the common cold, interferons have no place in everyday use. Further assessment of the effects of dipyridamole, ICI 130, 685, Impulsin (palmitate) and Pleconaril in preventing the common cold should be carried out. Given the multi-agent nature of the causes of the common cold, future research efforts should focus on non virus-specific compounds.

The regulation of rhinovirus infection in vitro by IL-8, HuIFN-alpha, and TNF-alpha

The influence of three important cytokines (IL-8, TNF-alpha, and HuIFN-alpha) on ongoing rhinovirus infections has been examined in vitro, individually or as combinations. TNF-alpha was able to transform traces of HRV infections into full-blown infections. Furthermore, TNF-alpha was able to down-regulate the antiviral action of HuIFN-alpha completely, even at levels of just a few pg/ml. This suggests that the induction of TNF-alpha by HRV may be part of the virus's strategy to minimize the interferon response which is part of the host's immune defence system. However, troxerutin (a flavonoid) was able to neutralize the downregulatory action of TNF-alpha on the HuIFN-alpha system at low levels and re-establish the antiviral activity ascribed to IFN-alpha. IL-8 exerted a minor influence on the interferon system, and had no influence on rhinovirus infections. The in vitro findings are supported, in part, by recent in vivo findings in a common cold pilot study.

Rhinovirus-induced PBMC responses and outcome of experimental infection in allergic subjects

BACKGROUND

The immune response to rhinovirus (RV) infections is considered to contribute to upper respiratory symptoms and may also be an important contributor to lower airway dysfunction in patients with asthma.

OBJECTIVE

This study was conducted to determine the relationship of RV-specific responses in PBMCs to the outcome of experimentally induced infection with RV16.

METHODS

Twenty-two subjects with either allergic rhinitis or asthma were inoculated with RV16: virus-induced proliferation and cytokine production were determined on PBMCs obtained before and then again 7 and 28 days after inoculation.

RESULTS

Several subjects had proliferative responses to RV16 before inoculation, and precold RV-specific proliferative responses were inversely correlated (r(s) = -0.62, P <. 005) with RV shedding after inoculation. In addition, there was a negative correlation (r(s) = -0.58, P = 0.01) between precold RV-induced IFN-gamma secretion ex vivo and peak RV shedding during the cold.

CONCLUSIONS

Certain RV-specific lymphocyte responses before the cold (vigorous proliferation or IFN-gamma secretion) were associated with reduced viral shedding after inoculation. These findings suggest that variations in mononuclear cell responses to RV could contribute to the individual variability in viral shedding during experimentally induced, and perhaps naturally acquired, RV infections in subjects with respiratory allergy or asthma.

The common cold: current therapy and natural history

Despite its prevalence, the common cold is complicated and can be difficult to treat, even symptomatically. There is still no cure for the myriad of viruses that cause the common cold. Many of the most popular remedies are either ineffective or counterproductive. This paper reviews the causes and course of upper respiratory infections, and discusses treatment options, including a new anticholinergic aqueous formulation for controlling rhinorrhea.

Nasal cytokines in common cold and allergic rhinitis

Coronavirus-induced common cold and allergen-induced rhinitis are characterized by nasal mucosal exudation of bulk blood plasma. The mucosal exudation process involves 'flooding' of the lamina propria with plasma-derived binding proteins and it is possible that subepithelial inflammatory cytokines and mediators may be moved by the exudate to the mucosal surface. In this study, we have analysed cytokine levels in nasal lavage (NAL) fluids from non-allergic subjects inoculated with coronavirus (n = 20) and from subjects with allergic (birch pollen) rhinitis subjected to additional allergen challenge (samples were obtained 35 min post challenge) in the laboratory (n = 10). Ten of the 20 inoculated subjects developed common cold and 10 remained healthy. Interferon-gamma (IFN gamma), interleukin-1 beta (IL-1 beta), granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-4, and IL-6 were analysed in unprocessed NAL fluids using immunoassays. The subjects who developed common cold had increased NAL fluid levels of IFN gamma (P < 0.05) that correlated well with the symptoms (P < 0.001). IFN gamma did not increase in subjects with allergic rhinitis. IL-1 beta levels were similar in NAL fluids obtained from all inoculated subjects. In the subjects with allergic rhinitis NAL fluid levels of both IL-1 beta and GM-CSF were increased (P < 0.05). GM-CSF was not detected in common cold. IL-4 and IL-6 were not detectable in any of the NAL fluids. The present cytokines may not only emanate from superficial mucosal cells. By aiding plasma exudation subepithelial cytokines may potentially also be retrieved on the mucosal surface.(ABSTRACT TRUNCATED AT 250 WORDS)

Literature Review: The Common Cold

Most colds are caused by rhinovirus infection, perhaps facilitated by chilling or stress. Virus infection begins in the nasopharynx and causes spotty destruction of the nasal ciliated epithelium. Transmission occurs chiefly via droplets of various sizes transported through the air, but some types of virus persist in moist secretions on handled objects and may retain their infectiousness. Living in crowded, poorly-ventilated quarters facilitates transmission. Not many virus particles survive in saliva and it is difficult to infect via the lips or mouth. Kissing does not efficiently spread cold infection. Prophylactic treatment with interferon does not protect against cold infection. Aspirin and acetaminophen reduced serum antibody response and increased nasal symptoms in a controlled Australian study. The combination of intranasal interferon and ipratropium with oral naproxen gave promising results in experimental rhinovirus inoculation. Basically, there has been little or no progress towards effective cold treatment in the past century.

A view from the Common Cold Unit

I have been asked to stand back and describe in broad terms the view I have had of common colds--probably the most frequent of acute human diseases and a long-lasting scientific problem--and in particular our recent work on antivirals. I should be able to do this for two reasons. Like everyone else I have suffered from colds, but in addition I have been studying the problem from the virological and clinical point of view for over 35 years--for the last 31 at the Common Cold Unit, Salisbury. As a result I may have problems with perspective--it is not possible to give a personal view and at the same time to describe something from every possible angle, and quite impossible to be comprehensive, but I have done my best and readers will make their own judgements and corrections.

The use of interferon-alpha in virus infections

The interferons (IFN) act too slowly to arrest acute viral infections, but interferon-alpha (IFN alpha) preparations have proved useful in some chronic infections and will clearly be used increasingly in these in the future. In the preparations derived from human leucocytes or cultured B lymphoblastoid cells, which are in routine clinical use, mixtures of a number of distinct subtypes of human IFN alpha have been identified. There are also 3 slightly different versions of the same single subtype, IFN alpha-2, made by recombinant DNA procedures in bacteria. IFN alpha preparations are injected intramuscularly or subcutaneously. Dose-related side effects are common but usually tolerable, but prolonged treatment may cause increasing fatigue and depression. Some patients form neutralising antibodies which block the effects of the IFN; these appear to be relatively more common after recombinant IFN alpha-2 than after IFN derived from human cells. Given intranasally, IFN alpha can prevent a subsequent experimental rhinovirus infection, or the spread of natural colds within a family. Repeated administration progressively damages the nasal mucosa, so that long term prophylaxis is not possible. IFN alpha has proved useful in patients with papillomavirus warts of the larynx, ano-genital region (condyloma acuminata) and skin (common warts). Treatment regimens remain to be optimised and are likely to include surgery or other treatments. IFN alpha and zidovudine (azidothymidine) synergistically inhibit the growth of HIV in vitro, and combination are on trial in patients with early AIDS. Very large doses of IFN alpha are effective against Kaposi's sarcoma in some AIDS patients. In chronic hepatitis B, continuing virus replication may lead to cirrhosis or primary liver cancer. Earlier clinical trials with IFN alpha gave inconclusive results, but recent large studies have confirmed that 25 to 40% of patients obtain benefit; this probably results from both the antiviral and the immunomodulatory effects of IFN alpha. In patients with chronic hepatitis C, the biochemical markers usually improve rapidly during IFN alpha administration, but relapse if treatment is stopped after only a few months; to increase the chances of sustained cure, the treatment period is now being prolonged.

Comparative susceptibility of respiratory viruses to recombinant interferons-alpha 2b and -beta

Intranasal recombinant interferon-alpha 2b (rIFN-alpha 2b) protects against natural colds due to rhinoviruses, but apparently not against those caused by viruses. Because rIFN-beta serine17 (rIFN-beta ser) appears less active than rIFN-alpha 2b in preventing natural rhinovirus colds, we compared the two IFNs in two in vitro assays against selected respiratory viruses. In a yield reduction assay, both IFNs had comparable activity against rhinovirus types 39 and 1A and coronavirus 229E, which were inhibited by 90% or more at IFN concentrations of 10(-11) to 10(-10) gram of protein/ml (approximately 2-20 IU/ml). Similar activities were observed with rIFN-beta ser against rhinoviruses isolated from clinical specimens. At concentrations of 10(-9) gram protein/ml, both IFNs inhibited the growth of influenza A and parainfluenza viruses, but not of adenovirus or respiratory syncytial virus in the cell culture systems tested. Thus, the different clinical protection conferred by rIFN-alpha 2b and rIFN-beta ser in studies of natural rhinovirus colds are not accounted for by differences in their in vitro activity against these viruses, and other explanations must be found.

von Willebrand factor is an acute phase reactant in man

Plasma von Willebrand factor antigen (vWfAg) concentrations in 19 patients with acute infectious illnesses of bacterial, viral or parasitic origin were significantly elevated with a mean greater than 3-fold above normal. In individual patients the elevation of vWf correlated strongly with the elevation of serum C-reactive protein (CRP). When patients were studied longitudinally, vWfAg and CRP concentrations both returned to normal values over 3-4 weeks. Similarly, in 14 volunteers infected with cold virus, vWfAg and CRP levels rose significantly and fell together during the course of infection. VWf is thus an acute phase reactant in man.