In vitro inhibition of SARS virus replication by human interferons

Safety and efficacy of inhaled interferon-β1a (SNG001) in adults with mild-to-moderate COVID-19: a randomized, controlled, phase II trial

Background

With the emergence of SARS-CoV-2 variants resistant to monoclonal antibody therapies and limited global access to therapeutics, the evaluation of novel therapeutics to prevent progression to severe COVID-19 remains a critical need.

Methods

Safety, clinical and antiviral efficacy of inhaled interferon-β1a (SNG001) were evaluated in a phase II randomized controlled trial on the ACTIV-2/A5401 platform (ClinicalTrials.govNCT04518410). Adult outpatients with confirmed SARS-CoV-2 infection within 10 days of symptom onset were randomized and initiated either orally inhaled nebulized SNG001 given once daily for 14 days (n = 110) or blinded pooled placebo (n = 110) between February 10 and August 18, 2021.

Findings

The proportion of participants reporting premature treatment discontinuation was 9% among SNG001 and 13% among placebo participants. There were no differences between participants who received SNG001 or placebo in the primary outcomes of treatment emergent Grade 3 or higher adverse events (3.6% and 8.2%, respectively), time to symptom improvement (median 13 and 9 days, respectively), or proportion with unquantifiable nasopharyngeal SARS-CoV-2 RNA at days 3 (28% [26/93] vs. 39% [37/94], respectively), 7 (65% [60/93] vs. 66% [62/94]) and 14 (91% [86/95] vs. 91% [83/81]). There were fewer hospitalizations with SNG001 (n = 1; 1%) compared with placebo (n = 7; 6%), representing an 86% relative risk reduction (p = 0.07). There were no deaths in either arm.

Interpretation

In this trial, SNG001 was safe and associated with a non-statistically significant decrease in hospitalization for COVID-19 pneumonia.

Funding

The ACTIV-2 platform study is funded by the NIH. Research reported in this publication was supported by the National Institute of Allergy and Infectious Diseases of the National Institutes of Health under Award Number UM1 AI068634, UM1 AI068636 and UM1 AI106701. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Reconsideration of interferon treatment for viral diseases: Lessons from SARS, MERS, and COVID-19

Periodic pandemics of coronavirus (CoV)-related pneumonia have been a major challenging issue since the outbreak of severe acute respiratory syndrome (SARS) in 2002 and Middle East respiratory syndrome (MERS) in 2012. The ongoing pandemic of CoV disease (COVID-19) poses a substantial threat to public health. As for the treatment options, only limited antiviral agents have been approved hitherto, and clinicians mainly focus on currently available drugs including the conventional antiviral interferons (IFNs). In clinical practice, IFNs, when used either alone or in combination with ribavirin and/or lopinavir/ritonavir, have shown promising outcomes, to some extent, in SARS-CoV or MERS-CoV treatment. Although the efficacy and safety of IFNs in COVID-19 treatment remain unclear, their possible use merits further evaluation. We present a review that summarizes current evidence of IFN treatment for COVID-19 and elaborates on other challenges in terms of the timing of IFN treatment initiation, treatment duration, and IFN type to be used. The review findings suggested that IFN acts by directly inhibiting viral replication and activating immune cell subsets. However, there is a lack of well-designed and controlled clinical trials providing firm evidence for the efficacy or safety of IFN therapy for CoVs. Additionally, critically ill patients with multiple immunosuppression-associated comorbidities may not benefit from IFN therapy, necessitating screening of those patients who would most benefit from IFN treatment.

Recombinant human interferon-α1b inhibits SARS-CoV-2 better than interferon-α2b in vitro

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A comprehensive evaluation method for anti-SARS-CoV-2 drugs was established based on qPCR, TCID₅₀, and immunofluorescence.

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A significant antiviral effect of rHuIFN-α1b was shown in Vero and Calu-3 ​cells.

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rHuIFN-α1b has a good potential in the application of anti-COVID-19 therapy.

Gemella morbillorum- and Capnocytophaga sp.-Related Mycotic Thoracic Aortic Aneurysm and Mediastinal Abscess: An Unusual Case Report, a Treatment Challenge, and a Review of Literature

A thoracic mycotic aortic aneurysm is an uncommon entity that can complicate mediastinal abscesses. Gemella morbillorum and Capnocytophaga sp. are oral bacteria that are very rarely encountered in this setting, especially when occurring together and with other organisms, posing a difficult treatment challenge per the available guidelines and sensitivities. We present in detail this interesting case of a multi-organism mediastinal abscess and thoracic mycotic aortic aneurysm after a previous esophagogastroduodenoscopic procedure in a 51-year-old female with known achalasia who presented with upper abdominal pain, including a successful surgical and antibiotic treatment regimen and a literature review of the involved topics.

The First Case Report of Mediastinal Abscess Caused by Gemella bergeri

Most cases of mediastinal abscess occur as a postoperative complication of a thoracic surgical procedure or following trauma. The most common causative microorganism is Staphylococcus aureus, but it can be rarely caused by unusual microorganisms, such as Gemella species. These are relatively difficult-to-identify commensal microorganisms of the upper respiratory and gastrointestinal tracts and may cause several infections. A 66-year-old man was diagnosed with Gemella bergeri mediastinal abscess by the molecular detection of bacterial genes. He was successfully treated with penicillin antibiotic for eight weeks. To our knowledge, this is the first case report of mediastinal abscess caused by G. bergeri.

Network-based virus-host interaction prediction with application to SARS-CoV-2

COVID-19, caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), has quickly become a global health crisis since the first report of infection in December of 2019. However, the infection spectrum of SARS-CoV-2 and its comprehensive protein-level interactions with hosts remain unclear. There is a massive amount of underutilized data and knowledge about RNA viruses highly relevant to SARS-CoV-2 and proteins of their hosts. More in-depth and more comprehensive analyses of that knowledge and data can shed new light on the molecular mechanisms underlying the COVID-19 pandemic and reveal potential risks. In this work, we constructed a multi-layer virus-host interaction network to incorporate these data and knowledge. We developed a machine-learning-based method to predict virus-host interactions at both protein and organism levels. Our approach revealed five potential infection targets of SARS-CoV-2 and 19 highly possible interactions between SARS-CoV-2 proteins and human proteins in the innate immune pathway.

The Immune Responses against Coronavirus Infections: Friend or Foe?

Coronaviruses (CoVs) were first discovered in the 1960s. Severe acute respiratory syndrome CoV-2 (SARS-CoV-2) has been identified as the cause of COVID-19, which spread throughout China and subsequently, across the world. As COVID-19 causes serious public health concerns across the world, investigating the characteristics of SARS-CoV-2 and its interaction with the host immune responses may provide a clearer picture of how the pathogen causes disease in some individuals. Interestingly, SARS-CoV-2 has 80% sequence homology with SARS-CoV-1 and 96-98% homology with CoVs isolated from bats. Therefore, the experience acquired in SARS and Middle East Respiratory Syndrome (MERS) epidemics may improve our understanding of the immune response and immunopathological changes in COVID-19 patients. In the present paper, we have reviewed the immune responses (including the innate and adaptive immunities) to SARS-CoV, MERS-CoV, and SARS-CoV-2, so as to improve our understanding of the concept of the COVID-19 disease, which will be helpful in developing vaccines and medications for treating the COVID-19 patients.

SARS-CoV-2 Infection and Risk Management in Multiple Sclerosis

The novel coronavirus can cause a severe respiratory disease with impact on the central nervous system, as has been reported by several medical health services. In the COVID-19 pandemic caused by the SARS-CoV-2 neurotrophic virus, neurologists have focused their attention on the early identification of suggestive manifestations of the neurological impact of the disease. In this context, they are exploring related chronic disease and the possibility of achieving a more effective understanding of symptoms derived from COVID-19 infection and those derived from the course of preexisting neurological disease. The present review summarizes evidence from the infection with SARS-CoV-2 and the management of the risks of multiple sclerosis and how it is related to the risks of general comorbidities associated with COVID-19. In addition, we reviewed other factors characteristic of MS, such as relapses, and the maximum tolerated dose of treatment medications from clinical and experimental evidence.

Type I Interferon (IFN)-Regulated Activation of Canonical and Non-Canonical Signaling Pathways

For several decades there has been accumulating evidence implicating type I interferons (IFNs) as key elements of the immune response. Therapeutic approaches incorporating different recombinant type I IFN proteins have been successfully employed to treat a diverse group of diseases with significant and positive outcomes. The biological activities of type I IFNs are consequences of signaling events occurring in the cytoplasm and nucleus of cells. Biochemical events involving JAK/STAT proteins that control transcriptional activation of IFN-stimulated genes (ISGs) were the first to be identified and are referred to as "canonical" signaling. Subsequent identification of JAK/STAT-independent signaling pathways, critical for ISG transcription and/or mRNA translation, are denoted as "non-canonical" or "non-classical" pathways. In this review, we summarize these signaling cascades and discuss recent developments in the field, specifically as they relate to the biological and clinical implications of engagement of both canonical and non-canonical pathways.

Biochemical indicators of coronavirus disease 2019 exacerbation and the clinical implications

Coronavirus Disease 2019 (COVID-19) has sparked a global pandemic, affecting more than 4 million people worldwide. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can cause acute lung injury (ALI) and even acute respiratory distress syndrome (ARDS); with a fatality of 7.0 %. Accumulating evidence suggested that the progression of COVID-19 is associated with lymphopenia and excessive inflammation, and a subset of severe cases might exhibit cytokine storm triggered by secondary hemophagocytic lymphohistiocytosis (sHLH). Furthermore, secondary bacterial infection may contribute to the exacerbation of COVID-19. We recommend using both IL-10 and IL-6 as the indicators of cytokine storm, and monitoring the elevation of procalcitonin (PCT) as an alert for initiating antibacterial agents. Understanding the dynamic progression of SARS-CoV-2 infection is crucial to determine an effective treatment strategy to reduce the rising mortality of this global pandemic.

COVID 19 mortality: Probable role of microbiome to explain disparity

There is a significant difference between COVID 19 associated mortality between different countries. Generally the number of deaths per million population are higher in the developed countries despite better health care efficiency, drinking water quality and expected healthy life span (HALE) at the time of birth. Developing and underdeveloped countries on the other hand have lower mortality even with higher rural and slum populations along with incidence of diarrhea because of lack of sanitation. We analyzed data from 122 countries out of which 80 were high or upper middle income and 42 were low or low middle income countries. There was statistically significant positive correlation between COVID 19 deaths /million population and water current score, health efficiency, and HALE. Statistically significant negative correlation was observed with % rural population and fraction of diarrhea because of inadequate sanitation for all ages. Moreover analysis of 51 countries showed that there is significant negative correlation between COVID 19 deaths /million population and proportion of total population living in slums. We propose that high microbial exposure particularly gram negative bacteria can possibly induce interferon type I which might have a protective effect against COVID 19 since the countries with less mortality also tend to have lack of sanitation and high incidence of attendant diseases. So, far none of the predictive models have taken into account immune status of populations engendered by environmental microbial exposure or microbiome. There might be a need to look at dynamics of COVID 19 pandemic using immune perspective. The approach can potentially inform better policies including interventions.

The underpinning biology relating to multiple sclerosis disease modifying treatments during the COVID-19 pandemic

BACKGROUND

SARS-CoV-2 viral infection causes COVID-19 that can result in severe acute respiratory distress syndrome (ARDS), which can cause significant mortality, leading to concern that immunosuppressive treatments for multiple sclerosis and other disorders have significant risks for both infection and ARDS.

OBJECTIVE

To examine the biology that potentially underpins immunity to the SARS-Cov-2 virus and the immunity-induced pathology related to COVID-19 and determine how this impinges on the use of current disease modifying treatments in multiple sclerosis.

OBSERVATIONS

Although information about the mechanisms of immunity are scant, it appears that monocyte/macrophages and then CD8 T cells are important in eliminating the SARS-CoV-2 virus. This may be facilitated via anti-viral antibody responses that may prevent re-infection. However, viral escape and infection of leucocytes to promote lymphopenia, apparent CD8 T cell exhaustion coupled with a cytokine storm and vascular pathology appears to contribute to the damage in ARDS.

IMPLICATIONS

In contrast to ablative haematopoietic stem cell therapy, most multiple-sclerosis-related disease modifying therapies do not particularly target the innate immune system and few have any major long-term impact on CD8 T cells to limit protection against COVID-19. In addition, few block the formation of immature B cells within lymphoid tissue that will provide antibody-mediated protection from (re)infection. However, adjustments to dosing schedules may help de-risk the chance of infection further and reduce the concerns of people with MS being treated during the COVID-19 pandemic.

Interferons in the Therapy of Severe Coronavirus Infections: A Critical Analysis and Recollection of a Forgotten Therapeutic Regimen with Interferon Beta

The pharmacological and immunological properties of interferons, especially those of interferon beta, and the corresponding treatment strategies are described, and the results of studies with different interferons in coronavirus infections are analysed. Furthermore, the data obtained with high-dosed native interferon beta in life-threatening acute viral diseases as well as the results of clinical pilot studies with high-dosed recombinant interferon beta-1a are provided because they serve as the rationale for the proposed therapeutic regimen to be applied in acute viral infections. This regimen differs from those approved for treatment of multiple sclerosis and consists of interferon beta-1a administered as a 24 hour intravenous infusion at a daily dose of up to 90 µg for 3-5 consecutive days. Since under this regimen transient severe side effects can occur, it is analysed which patients are suitable for this kind of treatment in general and if patients with severe coronavirus infections could also be treated accordingly.

Antiviral activities of type I interferons to SARS-CoV-2 infection

There is an urgent need to identify antivirals to curtail the COVID-19 pandemic. Herein, we report the sensitivity of SARS-CoV-2 to recombinant human interferons α and β (IFNα/β). Treatment with IFN-α or IFN-β at a concentration of 50 international units (IU) per milliliter reduces viral titers by 3.4 log or over 4 log, respectively, in Vero cells. The EC50 of IFN-α and IFN-β treatment is 1.35 IU/ml and 0.76 IU/ml, respectively, in Vero cells. These results suggest that SARS-CoV-2 is more sensitive than many other human pathogenic viruses, including SARS-CoV. Overall, our results demonstrate the potential efficacy of human Type I IFN in suppressing SARS-CoV-2 infection, a finding which could inform future treatment options for COVID-19.

Deciphering the Role of Host Genetics in Susceptibility to Severe COVID-19

Coronavirus disease-19 (COVID-19) describes a set of symptoms that develop following infection by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Whilst COVID-19 disease is most serious in patients with significant co-morbidities, the reason for healthy individuals succumbing to fulminant infection is largely unexplained. In this review, we discuss the most recent findings in terms of clinical features and the host immune response, and suggest candidate immune pathways that may be compromised in otherwise healthy individuals with fulminating COVID-19. On the basis of this early knowledge we reason a potential genetic effect on host immune response pathways leading to increased susceptibility to SARS-CoV-2 infection. Understanding these pathways may help not only in unraveling disease pathogenesis, but also in suggesting targets for therapy and prophylaxis. Importantly such insight should instruct efforts to identify those at increased risk in order to institute preventative measures, such as prophylactic medication and/or vaccination, when such opportunities arise in the later phases of the current pandemic or during future similar pandemics.

Interim Guidelines on Antiviral Therapy for COVID-19

Since the first case was reported in Wuhan, Hubei Province, China on December 12, 2019, Coronavirus disease 2019 (COVID-19) has spread widely to other countries since January 2020. As of April 16, 2020, 10635 confirmed cases have been reported, with 230 deaths in Korea. COVID-19 patients may be asymptomatic or show various clinical manifestations, including acute symptoms such as fever, fatigue, sore throat; pneumonia presenting as acute respiratory distress syndrome; and multiple organ failure. As COVID-19 has such varied clinical manifestations and case fatality rates, no standard antiviral therapy regimen has been established other than supportive therapy. In the present guideline, we aim to introduce potentially helpful antiviral and other drug therapies based on in vivo and in vitro research and clinical experiences from many countries.

Potent Antiviral Activities of Type I Interferons to SARS-CoV-2 Infection

The historical outbreak of COVID-19 disease not only constitutes a global public health crisis, but also has a devastating social and economic impact. The disease is caused by a newly identified coronavirus, Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2). There is an urgent need to identify antivirals to curtail the COVID-19 pandemic. Herein, we report the remarkable sensitivity of SARS-CoV-2 to recombinant human interferons α and β (IFNα/β). Treatment with IFN-α or IFN-β at a concentration of 50 international units (IU) per milliliter drastically reduce viral titers by 3.4 log or 4.5 log, respectively in Vero cells. The EC50 of IFN-α and IFN-β treatment is 1.35 IU/ml and 0.76 IU/ml, respectively, in Vero cells. These results suggested that SARS-CoV-2 is more sensitive to many other human pathogenic viruses, including the SARS-CoV. Overall, our results demonstrate the potent efficacy of human Type I IFN in suppressing SARS-CoV-2 replication, a finding which could inform future treatment options for COVID-19.

Characteristics and outcomes of Ludwig's angina in patients admitted to the intensive care unit: A 6-year retrospective study of 29 patients

Background/Purpose

Ludwig's angina (LA) still presents regularly and various characteristics are documented, but patients admitted to the Intensive Care Unit (ICU) has not been studied. The purpose of this study was to investigate the clinical characteristics and outcomes of patients with LA who were admitted to ICU.

Materials and methods

We retrospectively reviewed all 29 patients with LA who were admitted to the ICU of a university hospital from January 2013 to October 2018. Results were evaluated via descriptive analysis. The Log–Rank test was used to analyze the hospital/ICU length of stay (LOS).

Results

The male: female ratio was 2.63:1. Mean age was 53.41 ± 16.57 years (range 8–78 years). Concomitant conditions comprised diabetes mellitus in 10 patients (34.48%), and hypertension in six (20.69%). The main reason for ICU admission was surgical (44.83%). The mean Acute Physiology, Age, Chronic Health Evaluation II (APACHE II) and the Sequential Organ Failure Assessment (SOFA) scores were 13.52 ± 3.18 and 3.83 ± 2.89, respectively. Twenty-eight patients (96.55%) received respiratory support. Sixteen patients (55.17%) had positive bacterial culture results. Fourteen bacterial strains were detected, most of which were gram-positive (72.72%). Mean LOS was 6.89 ± 14.39 days (range 0.5–73 days), and 24.79 ± 16 days in the hospital. The ICU mortality rate was 10.34%. Compared with LA patients without descending necrotizing mediastinitis (DNM), those with DNM had longer ICU and hospital LOS. The laboratory investigations were higher.

Conclusion

LA patients in ICU were predominantly male, with a wide range age, high incidence of complications, long hospital LOS.

Gemella haemolysans bacteremia in a patient with secondary peritonitis due to a duodenal ulcer perforation: A case report

We describe a case of Gemella haemolysans septic shock in a 75-year old Japanese male with a duodenal perforation and secondary peritonitis. Blood cultures on admission were positive for Gram-positive and Gram-variable cocci, and G. haemolysans was identified using whole cell matrix-assisted laser desorpition/ionization mass spectrometry (MALDI-TOF MS), with a score value of 2.12. The 16S rRNA sequencing was difficult to use as a diagnostic test because there was more than 99% sequence homology with related bacterial strains. Based on both the biochemical profiles and whole groEL sequence, we concluded that the strain in our patient was G. haemolysans. The patient was successfully treated with a 16-day course of antimicrobials. His clinical condition improved, and no evidence of a relapse of the infection was noted. Although MALDI-TOF MS and 16S rRNA sequencing are useful for identification of the species, the basic biochemical profile is also important to identify a rare species.

Coronavirus virulence genes with main focus on SARS-CoV envelope gene

Coronavirus (CoV) infection is usually detected by cellular sensors, which trigger the activation of the innate immune system. Nevertheless, CoVs have evolved viral proteins that target different signaling pathways to counteract innate immune responses. Some CoV proteins act as antagonists of interferon (IFN) by inhibiting IFN production or signaling, aspects that are briefly addressed in this review. After CoV infection, potent cytokines relevant in controlling virus infections and priming adaptive immune responses are also generated. However, an uncontrolled induction of these proinflammatory cytokines can lead to pathogenesis and disease severity as described for SARS-CoV and MERS-CoV. The cellular pathways mediated by interferon regulatory factor (IRF)-3 and -7, activating transcription factor (ATF)-2/jun, activator protein (AP)-1, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and nuclear factor of activated T cells (NF-AT), are the main drivers of the inflammatory response triggered after viral infections, with NF-κB pathway the most frequently activated. Key CoV proteins involved in the regulation of these pathways and the proinflammatory immune response are revisited in this manuscript. It has been shown that the envelope (E) protein plays a variable role in CoV morphogenesis, depending on the CoV genus, being absolutely essential in some cases (genus α CoVs such as TGEV, and genus β CoVs such as MERS-CoV), but not in others (genus β CoVs such as MHV or SARS-CoV). A comprehensive accumulation of data has shown that the relatively small E protein elicits a strong influence on the interaction of SARS-CoV with the host. In fact, after infection with viruses in which this protein has been deleted, increased cellular stress and unfolded protein responses, apoptosis, and augmented host immune responses were observed. In contrast, the presence of E protein activated a pathogenic inflammatory response that may cause death in animal models and in humans. The modification or deletion of different motifs within E protein, including the transmembrane domain that harbors an ion channel activity, small sequences within the middle region of the carboxy-terminus of E protein, and its most carboxy-terminal end, which contains a PDZ domain-binding motif (PBM), is sufficient to attenuate the virus. Interestingly, a comprehensive collection of SARS-CoVs in which these motifs have been modified elicited full and long-term protection even in old mice, making those deletion mutants promising vaccine candidates. These data indicate that despite its small size, E protein drastically influences the replication of CoVs and their pathogenicity. Although E protein is not essential for CoV genome replication or subgenomic mRNA synthesis, it affects virus morphogenesis, budding, assembly, intracellular trafficking, and virulence. In fact, E protein is responsible in a significant proportion of the inflammasome activation and the associated inflammation elicited by SARS-CoV in the lung parenchyma. This exacerbated inflammation causes edema accumulation leading to acute respiratory distress syndrome (ARDS) and, frequently, to the death of infected animal models or human patients.

Tropism of and innate immune responses to the novel human betacoronavirus lineage C virus in human ex vivo respiratory organ cultures

Since April 2012, there have been 17 laboratory-confirmed human cases of respiratory disease associated with newly recognized human betacoronavirus lineage C virus EMC (HCoV-EMC), and 7 of them were fatal. The transmissibility and pathogenesis of HCoV-EMC remain poorly understood, and elucidating its cellular tropism in human respiratory tissues will provide mechanistic insights into the key cellular targets for virus propagation and spread. We utilized ex vivo cultures of human bronchial and lung tissue specimens to investigate the tissue tropism and virus replication kinetics following experimental infection with HCoV-EMC compared with those following infection with human coronavirus 229E (HCoV-229E) and severe acute respiratory syndrome coronavirus (SARS-CoV). The innate immune responses elicited by HCoV-EMC were also investigated. HCoV-EMC productively replicated in human bronchial and lung ex vivo organ cultures. While SARS-CoV productively replicated in lung tissue, replication in human bronchial tissue was limited. Immunohistochemistry revealed that HCoV-EMC infected nonciliated bronchial epithelium, bronchiolar epithelial cells, alveolar epithelial cells, and endothelial cells. Transmission electron microscopy showed virions within the cytoplasm of bronchial epithelial cells and budding virions from alveolar epithelial cells (type II). In contrast, there was minimal HCoV-229E infection in these tissues. HCoV-EMC failed to elicit strong type I or III interferon (IFN) or proinflammatory innate immune responses in ex vivo respiratory tissue cultures. Treatment of human lung tissue ex vivo organ cultures with type I IFNs (alpha and beta IFNs) at 1 h postinfection reduced the replication of HCoV-EMC, suggesting a potential therapeutic use of IFNs for treatment of human infection.

SARS coronavirus pathogenesis: host innate immune responses and viral antagonism of interferon

SARS-CoV is a pathogenic coronavirus that emerged from a zoonotic reservoir, leading to global dissemination of the virus. The association SARS-CoV with aberrant cytokine, chemokine, and Interferon Stimulated Gene (ISG) responses in patients provided evidence that SARS-CoV pathogenesis is at least partially controlled by innate immune signaling. Utilizing models for SARS-CoV infection, key components of innate immune signaling pathways have been identified as protective factors against SARS-CoV disease, including STAT1 and MyD88. Gene transcription signatures unique to SARS-CoV disease states have been identified, but host factors that regulate exacerbated disease phenotypes still remain largely undetermined. SARS-CoV encodes several proteins that modulate innate immune signaling through the antagonism of the induction of Interferon and by avoidance of ISG effector functions.

Single-dose intranasal administration with mDEF201 (adenovirus vectored mouse interferon-alpha) confers protection from mortality in a lethal SARS-CoV BALB/c mouse model

Interferons (IFNs) are a first line of defense against viral infection. Herein we describe the use of an adenovirus vectored mouse IFN alpha gene (mDEF201) as a prophylactic and treatment countermeasure in a SARS-CoV-infected BALB/c mouse model. Complete survival protection was observed in mice given a single dose of mDEF201 administered intranasally 1, 3, 5, 7, or 14 days prior to lethal SARS-CoV challenge (p < 0.001), and body weights of these treated mice were unaffected by the challenge. In addition, low doses of mDEF201 protected lungs in a dose dependent manner as measured by a reduction in gross pathology. Intranasal treatment with mDEF201 ranging from 10⁶ to 10⁸ PFU significantly protected mice against a lethal SARS-CoV infection in a dose dependent manner up to 12 h post infection (p < 0.001). The data suggest that mDEF201 is a new class of antiviral agent further development as treatment for SARS-CoV infections.

Therapies for coronaviruses. Part 2: Inhibitors of intracellular life cycle

BACKGROUND

Severe acute respiratory syndrome (SARS) coronavirus emerged from an animal reservoir in 2002 and has the potential to reemerge, as shown by the occurrence of non-laboratory-associated new cases in the winter of 2003. In the absence of a vaccine, broad spectrum anticoronaviral medications are needed.

OBJECTIVE

Anticoronavirals targeting viral entry were reviewed in part I. Here we review anticoronaviral therapies directed against the intracellular life cycle, with an emphasis on allowed patents and pending patents.

METHOD

The published literature, in particular, patent publications is searched for relevant documents. The information is organized and critiqued.

RESULTS/CONCLUSION

Many promising anticoronaviral strategies are identified. Monoclonal antibodies, protease inhibitors, interferon-based drugs and nucleic-acid based antivirals are most advanced, each having its own advantages and disadvantages. A multi-pronged approach, keeping all venues open, is advocated.

Recent antiviral strategies against human coronavirus-related respiratory illnesses

PURPOSE OF REVIEW

The main purpose of this review is to summarize the current research (2006-2007) concerning the development of novel anticoronaviral strategies and compounds.

RECENT FINDINGS

Recent research led to the identification of several novel agents inhibiting coronaviral replication. The most promising compounds include carbohydrate-binding agents, neutralizing antibodies and drugs targeting a coronaviral envelope protein.

SUMMARY

Although initial outbreaks of coronavirus that causes severe acute respiratory syndrome (SARS-CoV) were controlled by public health measures, the development of vaccines and antiviral agents for SARS-CoV is essential for improving control and treatment of future outbreaks. Four years after the SARS-CoV epidemic, several compounds with an anticoronaviral activity have been identified.

Severe acute respiratory syndrome coronavirus as an agent of emerging and reemerging infection

Before the emergence of severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV) in 2003, only 12 other animal or human coronaviruses were known. The discovery of this virus was soon followed by the discovery of the civet and bat SARS-CoV and the human coronaviruses NL63 and HKU1. Surveillance of coronaviruses in many animal species has increased the number on the list of coronaviruses to at least 36. The explosive nature of the first SARS epidemic, the high mortality, its transient reemergence a year later, and economic disruptions led to a rush on research of the epidemiological, clinical, pathological, immunological, virological, and other basic scientific aspects of the virus and the disease. This research resulted in over 4,000 publications, only some of the most representative works of which could be reviewed in this article. The marked increase in the understanding of the virus and the disease within such a short time has allowed the development of diagnostic tests, animal models, antivirals, vaccines, and epidemiological and infection control measures, which could prove to be useful in randomized control trials if SARS should return. The findings that horseshoe bats are the natural reservoir for SARS-CoV-like virus and that civets are the amplification host highlight the importance of wildlife and biosecurity in farms and wet markets, which can serve as the source and amplification centers for emerging infections.

A CpG oligodeoxynucleotide inducing anti-coxsackie B3 virus activity in human peripheral blood mononuclear cells

Coxsackie B3 virus (CVB3) is the most significant pathogen causing myocarditis in humans, and antiviral therapy would be most effective in the early stages of the disease. Here we provide evidence that BW001, a C-type CpG oligodeoxynucleotide, induces anti-CVB3 activity in human peripheral blood mononuclear cells (PBMCs). In parallel, we have demonstrated that BW001 induces human PBMCs to express mRNAs of multiple types of interferon (IFN), including IFN-alpha, IFN-beta, IFN-omega and IFN-gamma, and to express mRNAs of at least 11 subtypes of IFN-alpha. The induced IFNs may contribute to the anti-CVB3 activity. The results suggest that BW001 could be developed into a medication with the potential to treat CVB3 infectious diseases by inducing natural mixed IFNs.

The synergistic interaction of interferon types I and II leads to marked reduction in severe acute respiratory syndrome-associated coronavirus replication and increase in the expression of mRNAs for interferon-induced proteins

Interferon (IFN)-α, -β and -γ have been shown to be only marginally effective against severe acute respiratory syndrome coronavirus (SARS-CoV) replication in Vero cell lines. We investigated the combination of type I IFNs (IFN-α or -β) and IFN-γ for antiviral activity and found that such combinations synergistically inhibited SARS-CoV replication in Vero cells, using yield reduction assay and the isobologram and combination index methods of Chou and Talalay for evaluation. The highly synergistic anti-SARS-CoV action of type I IFNs and IFN-γ parallels the marked increase in 2′-5′-oligoadenylate synthetase and p56 mRNAs following exposure in Vero cells to either IFN-α or -β and IFN-γ compared with the transcriptional levels obtained after stimulation with either IFN alone. These results demonstrate that SARS-CoV, although only moderately sensitive to the antiviral action of the individual types of IFN, is highly sensitive to a combination of type I and II IFNs, which suggests that such combinations may have potential in the treatment of SARS-CoV infections.

Anti-SARS-CoV immunity induced by a novel CpG oligodeoxynucleotide

To develop CpG oligodeoxynucleotides (CpG ODNs) based therapy for prevention and treatment of severe acute respiratory syndrome (SARS), we selected a novel CpG ODN (BW001), which displays B-type CpG ODN structure feature at the 5′ and A-type CpG ODN structure feature at the 3′, and tested for its anti-SARS-CoV activity. We found that the supernatants of human PBMCs stimulated by BW001 significantly protected Vero cells from SARS-CoV infection. BW001 could stimulate human PBMCs and pDCs to secrete high level of IFN-α and promote human PBMCs and B cells to proliferate. Furthermore, we demonstrated that BW001 could activate CD19⁺ B cells and CD56⁺ NK cells in human PBMCs. In addition, BW001 could enhance NK cytotoxicity and IFN-γ secretion in human PBMCs. Together, BW001 represents a novel type of CpG ODN and may have potential for the development of treatment and prevention for SARS as well as other viral associated diseases.

Development of antiviral therapy for severe acute respiratory syndrome

A new disease, the severe acute respiratory distress syndrome (SARS), caused by the SARS coronavirus (SARS-CoV), emerged at the beginning of 2003 and rapidly spread throughout the world. Although the disease had disappeared in June 2003 its re-emergence cannot be excluded. The development of vaccines against SARS-CoV may take years. Therefore, the availability of effective antiviral drugs against SARS-CoV may be crucial for the control of future SARS outbreaks. In this review, experimental and clinical data about potential anti-SARS drugs is summarised and discussed. Animal model studies will be needed to help to determine which interventions warrant controlled clinical testing.