Publications by authors named "Eun-Ha Kim"

105 Publications

Age-dependent pathogenic characteristics of SARS-CoV-2 infection in ferrets.

Nat Commun 2022 01 10;13(1):21. Epub 2022 Jan 10.

College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Republic of Korea.

While the seroprevalence of SARS-CoV-2 in healthy people does not differ significantly among age groups, those aged 65 years or older exhibit strikingly higher COVID-19 mortality compared to younger individuals. To further understand differing COVID-19 manifestations in patients of different ages, three age groups of ferrets are infected with SARS-CoV-2. Although SARS-CoV-2 is isolated from all ferrets regardless of age, aged ferrets (≥3 years old) show higher viral loads, longer nasal virus shedding, and more severe lung inflammatory cell infiltration, and clinical symptoms compared to juvenile (≤6 months) and young adult (1-2 years) groups. Furthermore, direct contact ferrets co-housed with the virus-infected aged group shed more virus than direct-contact ferrets co-housed with virus-infected juvenile or young adult ferrets. Transcriptome analysis of aged ferret lungs reveals strong enrichment of gene sets related to type I interferon, activated T cells, and M1 macrophage responses, mimicking the gene expression profile of severe COVID-19 patients. Thus, SARS-CoV-2-infected aged ferrets highly recapitulate COVID-19 patients with severe symptoms and are useful for understanding age-associated infection, transmission, and pathogenesis of SARS-CoV-2.
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http://dx.doi.org/10.1038/s41467-021-27717-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8748994PMC
January 2022

Comparison of contralateral oblique view with the lateral view for fluoroscopic-guided cervical epidural steroid injection: a randomized clinical trial.

Reg Anesth Pain Med 2021 Dec 1. Epub 2021 Dec 1.

Asan Medical Center, Songpa-gu, Seoul, Republic of Korea.

Background: Cervical epidural steroid injection is associated with rare but potentially catastrophic complications. The contralateral oblique (CLO) view may be a safe and feasible alternative to the lateral (LAT) view for fluoroscopic-guided cervical epidural steroid injection. However, evidence for the clinical usefulness of the CLO view for cervical epidural steroid injection is lacking. We assessed the clinical usefulness of the CLO view for cervical epidural steroid injection in managing cervical herniated intervertebral discs.

Methods: Patients were randomly assigned to receive fluoroscopic-guided cervical epidural steroid injection under LAT view or CLO view at 50±5° degrees groups. The primary outcome was the needling time comparison between the two groups. Secondary outcomes were comparison of first-attempt success rate, needle tip visualization and location, total number of needle passes, final success rate, crossover success rate and false-positive/negative loss of resistance. Complications and radiation dose were also compared.

Results: The needling time significantly decreased in the CLO than in the LAT group. The first-attempt success rate was significantly higher in the CLO compared with the LAT group. The needle tip was clearly visualized (p<0.001) and located more often on (or just anterior to) the ventral interlaminar line (p<0.001) in the CLO than in the LAT group. There were significantly fewer needle passes (p=0.019) in the CLO than in the LAT group. There were no significant differences in the final success, crossover success, false-positive/negative loss of resistance or radiation dose between the groups. Two (5.9%) cases in the LAT group experienced complications.

Conclusion: The CLO view may be recommended for fluoroscopic-guided cervical epidural steroid injection, considering its better clinical usefulness over the LAT view.
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http://dx.doi.org/10.1136/rapm-2021-103177DOI Listing
December 2021

Antiviral effects of human placenta hydrolysate (Laennec) against SARS-CoV-2 in vitro and in the ferret model.

J Microbiol 2021 Nov 6;59(11):1056-1062. Epub 2021 Oct 6.

GREENCROSS WellBeing Co., Ltd., Seoul, 07335, Republic of Korea.

The COVID-19 pandemic has caused unprecedented health, social, and economic crises worldwide. However, to date, there is an only a limited effective treatment for this disease. Human placenta hydrolysate (hPH) has previously been shown to be safe and to improve the health condition in patients with hyperferritinemia and COVID-19. In this study, we aimed to determine the antiviral effects of hPH against SARS-CoV-2 in vitro and in vivo models and compared with Remdesivir, an FDA-approved drug for COVID-19 treatment. To assess whether hPH inhibited SARS-CoV-2 replication, we determined the CC, EC, and selective index (SI) in Vero cells by infection with a SARS-CoV-2 at an MOI of 0.01. Further, groups of ferrets infected with 10 TCID/ml of SARS-CoV-2 and treated with hPH at 2, 4, 6 dpi, and compared their clinical manifestation and virus titers in respiratory tracts with PBS control-treated group. The mRNA expression of immune-related cytokines was determined by qRT-PCR. hPH treatment attenuated virus replication in a dose-dependent manner in vitro. In a ferret infection study, treatment with hPH resulted in minimal bodyweight loss and attenuated virus replication in the nasal wash, turbinates, and lungs of infected ferrets. In addition, qRT-PCR results revealed that the hPH treatment remarkably upregulated the gene expression of type I (IFN-α and IFN-β) and II (IFN-γ) IFNs in SARS-CoV-2 infected ferrets. Our data collectively suggest that hPH has antiviral efficacy against SARS-CoV-2 and might be a promising therapeutic agent for the treatment of SARS-CoV-2 infection.
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http://dx.doi.org/10.1007/s12275-021-1367-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8493534PMC
November 2021

Single-cell transcriptome of bronchoalveolar lavage fluid reveals sequential change of macrophages during SARS-CoV-2 infection in ferrets.

Nat Commun 2021 07 27;12(1):4567. Epub 2021 Jul 27.

Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea.

Few studies have used a longitudinal approach to describe the immune response to SARS-CoV-2 infection. Here, we perform single-cell RNA sequencing of bronchoalveolar lavage fluid cells longitudinally obtained from SARS-CoV-2-infected ferrets. Landscape analysis of the lung immune microenvironment shows distinct changes in cell proportions and characteristics compared to uninfected control, at 2 and 5 days post-infection (dpi). Macrophages are classified into 10 distinct subpopulations with transcriptome changes among monocyte-derived infiltrating macrophages and differentiated M1/M2 macrophages, notably at 2 dpi. Moreover, trajectory analysis reveals gene expression changes from monocyte-derived infiltrating macrophages toward M1 or M2 macrophages and identifies a macrophage subpopulation that has rapidly undergone SARS-CoV-2-mediated activation of inflammatory responses. Finally, we find that M1 or M2 macrophages show distinct patterns of gene modules downregulated by immune-modulatory drugs. Overall, these results elucidate fundamental aspects of the immune response dynamics provoked by SARS-CoV-2 infection.
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http://dx.doi.org/10.1038/s41467-021-24807-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8316405PMC
July 2021

Differences in seroprevalence between epicenter and non-epicenter areas of the COVID-19 outbreak in South Korea.

J Microbiol 2021 May 28;59(5):530-533. Epub 2021 Apr 28.

College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, 28644, Republic of Korea.

To compare the standardized severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence of high epicenter region with non-epicenter region, serological studies were performed with a total of 3,268 sera from Daegu City and 3,981 sera from Chungbuk Province. Indirect immunofluorescence assay (IFA) for SARS-CoV-2 IgG results showed a high seroprevalence rate in the Daegu City (epicenter) compared with a non-epicenter area (Chungbuk Province) (1.27% vs. 0.91%, P = 0.0358). It is noteworthy that the highest seroprevalence in Daegu City was found in elderly patients (70's) whereas young adult patients (20's) in Chungbuk Province showed the highest seroprevalence. Neutralizing antibody (NAb) titers were found in three samples from Daegu City (3/3, 268, 0.09%) while none of the samples from Chungbuk Province were NAb positive. These results demonstrated that even following the large outbreak, the seropositive rate of SARS-CoV-2 in the general population remained low in South Korea.
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http://dx.doi.org/10.1007/s12275-021-1095-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8079228PMC
May 2021

Age-dependent pathogenic characteristics of SARS-CoV-2 infection in ferrets.

Res Sq 2021 Mar 29. Epub 2021 Mar 29.

Chungbuk National University.

While the seroprevalence of SARS-CoV-2 in healthy people does not differ significantly among age groups, those aged 65 years or older exhibit strikingly higher COVID-19 mortality compared to younger individuals. To further understand differing COVID-19 manifestations in patients of different ages, three age groups of ferrets were infected with SARS-CoV-2. Although SARS-CoV-2 was isolated from all ferrets regardless of age, aged ferrets (≥ 3 years old) showed higher viral loads, longer nasal virus shedding, and more severe lung inflammatory cell infiltration and clinical symptoms compared to juvenile (≤ 6 months) and young adult (1-2 years) groups. Transcriptome analysis of aged ferret lungs revealed strong enrichment of gene sets related to type I interferon, activated T cells, and M1 macrophage responses, mimicking the gene expression profile of severe COVID-19 patients. Thus, SARS-CoV-2-infected aged ferrets highly recapitulate COVID-19 patients with severe symptoms and are useful for understanding age-associated infection, transmission, and pathogenesis of SARS-CoV-2.
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http://dx.doi.org/10.21203/rs.3.rs-131380/v2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8020987PMC
March 2021

Pathogenic assessment of avian influenza viruses in migratory birds.

Emerg Microbes Infect 2021 Dec;10(1):565-577

College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Korea.

Several subtypes of avian influenza (AI) viruses have caused human infections in recent years; however, there is a severe knowledge gap regarding the capacity of wild bird viruses to infect mammals. To assess the risk of mammalian infection by AI viruses from their natural reservoirs, a panel of isolates from 34 wild birds was examined in animal models. All selected AI virus subtypes were found to predominantly possess Eurasian lineage, although reassortment with North American lineage AI viruses was also noted in some isolates. When used to infect chickens, 20 AI isolates could be recovered from oropharyngeal swabs at 5 days post-infection (dpi) without causing significant morbidity. Similarly, mild to no observable disease was observed in mice infected with these viruses although the majority replicated efficiently in murine lungs. As expected, wild bird AI isolates were found to recognize avian-like receptors, while a few strains also exhibited detectable human-like receptor binding. Selected strains were further tested in ferrets, and 15 out of 20 were found to shed the virus in the upper respiratory tract until 5 dpi. Overall, we demonstrate that a diversity of low-pathogenic AI viruses carried by wild migratory birds have the capacity to infect land-based poultry and mammalian hosts while causing minimal signs of clinical disease. This study reiterates that there is a significant capacity for interspecies transmission of AI viruses harboured by wild aquatic birds. Thus, these viruses pose a significant threat to human health underscoring the need for continued surveillance.
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http://dx.doi.org/10.1080/22221751.2021.1899769DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8018353PMC
December 2021

Compositional equivalence assessment of insect-resistant genetically modified rice using multiple statistical analyses.

GM Crops Food 2021 Jan;12(1):303-314

National Institute of Agricultural Sciences, Rural Development Administration, Jeollabuk-do, Republic of Korea.

The safety of transgenic Bt rice containing bacteria-derived gene from (Bt) was assessed by conducting field trials at two locations for two consecutive years in South Korea, using the near-isogenic line comparator rice cultivar ('Ilmi', non-Bt rice) and four commercial cultivars as references. Compositional analyses included measurement of proximates, minerals, amino acids, fatty acids, vitamins, and antinutrients. Significant differences between Bt rice and non-Bt rice were detected; however, all differences were within the reference range. The statistical analyses, including analysis of % variability, analysis of similarities (ANOISM), similarity percentage (SIMPER) analysis, and permutational multivariate analysis of variance (PERMANOVA) were performed to study factors contributing to compositional variability. The multivariate analyses revealed that environmental factors more influenced rice components' variability than by genetic factors. This approach was shown to be a powerful method to provide meaningful evaluations between Bt rice and its comparators. In this study, Bt rice was proved to be compositionally equivalent to conventional rice varieties through multiple statistical methods.
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http://dx.doi.org/10.1080/21645698.2021.1893624DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7928020PMC
January 2021

Molecular Signatures of Inflammatory Profile and B-Cell Function in Patients with Severe Fever with Thrombocytopenia Syndrome.

mBio 2021 02 16;12(1). Epub 2021 Feb 16.

College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Republic of Korea

Dabie bandavirus (severe fever with thrombocytopenia syndrome virus [SFTSV]) induces an immunopathogenic disease with a high fatality rate; however, the mechanisms underlying its clinical manifestations are largely unknown. In this study, we applied targeted proteomics and single-cell transcriptomics to examine the differential immune landscape in SFTS patient blood. Serum immunoprofiling identified low-risk and high-risk clusters of SFTS patients based on inflammatory cytokine levels, which corresponded to disease severity. Single-cell transcriptomic analysis of SFTS patient peripheral blood mononuclear cells (PBMCs) at different infection stages showed pronounced expansion of B cells with alterations in B-cell subsets in fatal cases. Furthermore, plasma cells in which the interferon (IFN) pathway is downregulated were identified as the primary reservoir of SFTSV replication. This study identified not only the molecular signatures of serum inflammatory cytokines and B-cell lineage populations in SFTSV-induced fatalities but also plasma cells as the viral reservoir. Thus, this suggests that altered B-cell function is linked to lethality in SFTSV infections. SFTSV is an emerging virus discovered in China in 2009; it has since spread to other countries in East Asia. Although the fatality rates of SFTSV infection range from 5.3% to as high as 27%, the mechanisms underlying clinical manifestations are largely unknown. In this study, we demonstrated that SFTSV infection in fatal cases caused an excessive inflammatory response through high induction of proinflammatory cytokines and chemokines and the aberrant inactivation of adaptive immune responses. Furthermore, single-cell transcriptome sequencing (RNA-seq) analysis of SFTS patient PBMCs revealed that SFTSV targets the B-cell lineage population, especially plasma cells, as the potential viral reservoir in patients for whom the infection is fatal. Thus, SFTSV infection may inhibit high-affinity antibody maturation and secretion of plasma B cells, suppressing neutralizing antibody production and thereby allowing significant virus replication and subsequent fatality.
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http://dx.doi.org/10.1128/mBio.02583-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8545090PMC
February 2021

A therapeutic neutralizing antibody targeting receptor binding domain of SARS-CoV-2 spike protein.

Nat Commun 2021 01 12;12(1):288. Epub 2021 Jan 12.

College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Republic of Korea.

Vaccines and therapeutics are urgently needed for the pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we screen human monoclonal antibodies (mAb) targeting the receptor binding domain (RBD) of the viral spike protein via antibody library constructed from peripheral blood mononuclear cells of a convalescent patient. The CT-P59 mAb potently neutralizes SARS-CoV-2 isolates including the D614G variant without antibody-dependent enhancement effect. Complex crystal structure of CT-P59 Fab/RBD shows that CT-P59 blocks interaction regions of RBD for angiotensin converting enzyme 2 (ACE2) receptor with an orientation that is notably different from previously reported RBD-targeting mAbs. Furthermore, therapeutic effects of CT-P59 are evaluated in three animal models (ferret, hamster, and rhesus monkey), demonstrating a substantial reduction in viral titer along with alleviation of clinical symptoms. Therefore, CT-P59 may be a promising therapeutic candidate for COVID-19.
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http://dx.doi.org/10.1038/s41467-020-20602-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7803729PMC
January 2021

Critical role of neutralizing antibody for SARS-CoV-2 reinfection and transmission.

Emerg Microbes Infect 2021 Dec;10(1):152-160

College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Republic of Korea.

Cases of laboratory-confirmed SARS-CoV-2 reinfection have been reported in a number of countries. Further, the level of natural immunity induced by SARS-CoV-2 infection is not fully clear, nor is it clear if a primary infection is protective against reinfection. To investigate the potential association between serum antibody titres and reinfection of SARS-CoV-2, ferrets with different levels of NAb titres after primary SARS-CoV-2 infection were subjected to reinfection with a heterologous SARS-CoV-2 strain. All heterologous SARS-CoV-2 reinfected ferrets showed active virus replication in the upper respiratory and gastro-intestinal tracts. However, the high NAb titre group showed attenuated viral replication and rapid viral clearance. In addition, direct-contact transmission was observed only from reinfected ferrets with low NAb titres (<20), and not from other groups. Further, lung histopathology demonstrated the presence of limited inflammatory regions in the high NAb titre groups compared with control and low NAb groups. This study demonstrates a close correlation between a low NAb titre and SARS-CoV-2 reinfection in a recovered ferret reinfection model.
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http://dx.doi.org/10.1080/22221751.2021.1872352DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7832474PMC
December 2021

Comparison of the seed nutritional composition between conventional varieties and transgenic soybean overexpressing Physaria FAD3-1.

J Sci Food Agric 2021 Apr 18;101(6):2601-2613. Epub 2021 Jan 18.

Biosafety Division, National Institute of Agricultural Sciences, Jeonju, South Korea.

Background: PfFAD3 transgenic soybean expressing omega-3 fatty acid desaturase 3 of Physaria produces increased level of α-linolenic acid in seed. Composition data of non-transgenic conventional varieties is important in the safety assessment of the genetically-modified (GM) crops in the context of the natural variation.

Results: The natural variation was characterized in seed composition of 13 Korean soybean varieties grown in three locations in South Korea for 2 years. Univariate analysis of combined data showed significant differences by variety and cultivation environment for proximates, minerals, anti-nutrients, and fatty acids. Percent variability analysis demonstrated that genotype, environment and the interaction of environment with genotype contributed to soybean seed compositions. Principal component analysis and orthogonal projections to latent structure discriminant analysis indicated that significant variance in compositions was attributable to location and cultivation year. The composition of three PfFAD3 soybean lines for proximates, minerals, anti-nutrients, and fatty acids was compared to a non-transgenic commercial comparator (Kwangankong, KA), and three non-transgenic commercial varieties grown at two sites in South Korea. Only linoleic and linolenic acids significantly differed in PfFAD3-1 lines compared to KA, which were expected changes by the introduction of the PfFAD3-1 trait in KA.

Conclusion: Genotype, environment, and the interaction of environment with genotype contributed to compositional variability in soybean. PfFAD3-1 soybean is equivalent to the conventional varieties with respect to these components. © 2020 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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http://dx.doi.org/10.1002/jsfa.11028DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8048611PMC
April 2021

Development of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) thermal inactivation method with preservation of diagnostic sensitivity.

J Microbiol 2020 Oct 29;58(10):886-891. Epub 2020 Sep 29.

College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, 28644, Republic of Korea.

Various treatments and agents had been reported to inactivate RNA viruses. Of these, thermal inactivation is generally considered an effective and cheap method of sample preparation for downstream assays. The purpose of this study is to establish a safe inactivation method for SARS-CoV-2 without compromising the amount of amplifiable viral genome necessary for clinical diagnoses. In this study, we demonstrate the infectivity and genomic stability of SARSCoV- 2 by thermal inactivation at both 56°C and 65°C. The results substantiate that viable SARS-CoV-2 is readily inactivated when incubated at 56°C for 30 min or at 65°C for 10 min. qRT-PCR of specimens heat-inactivated at 56°C for 30 min or 65°C for 15 min revealed similar genomic RNA stability compared with non-heat inactivated specimens. Further, we demonstrate that 30 min of thermal inactivation at 56°C could inactivate viable viruses from clinical COVID-19 specimens without attenuating the qRT-PCR diagnostic sensitivity. Heat treatment of clinical specimens from COVID-19 patients at 56°C for 30 min or 65°C for 15 min could be a useful method for the inactivation of a highly contagious agent, SARS-CoV-2. Use of this method would reduce the potential for secondary infections in BSL2 conditions during diagnostic procedures. Importantly, infectious virus can be inactivated in clinical specimens without compromising the sensitivity of the diagnostic RT-PCR assay.
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http://dx.doi.org/10.1007/s12275-020-0335-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7522010PMC
October 2020

Viable SARS-CoV-2 in various specimens from COVID-19 patients.

Clin Microbiol Infect 2020 Nov 23;26(11):1520-1524. Epub 2020 Jul 23.

Department of Microbiology, Chungbuk National University College of Medicine and Medical Research Institute, Cheongju, Republic of Korea; Zoonotic Infectious Disease Research Center, Chungbuk National University, Cheongju, Republic of Korea. Electronic address:

Objectives: The aim was to determine whether various clinical specimens obtained from COVID-19 patients contain the infectious virus.

Methods: To demonstrate whether various clinical specimens contain the viable virus, we collected naso/oropharyngeal swabs and saliva, urine and stool samples from five COVID-19 patients and performed a quantitative polymerase chain reaction (qPCR) to assess viral load. Specimens positive with qPCR were subjected to virus isolation in Vero cells. We also used urine and stool samples to intranasally inoculate ferrets and evaluated the virus titres in nasal washes on 2, 4, 6 and 8 days post infection.

Results: SARS-CoV-2 RNA was detected in all naso/oropharyngeal swabs and saliva, urine and stool samples collected between days 8 and 30 of the clinical course. Notably, viral loads in urine, saliva and stool samples were almost equal to or higher than those in naso/oropharyngeal swabs (urine 1.08 ± 0.16-2.09 ± 0.85 log copies/mL, saliva 1.07 ± 0.34-1.65 ± 0.46 log copies/mL, stool 1.17 ± 0.32 log copies/mL, naso/oropharyngeal swabs 1.18 ± 0.12-1.34 ± 0.30 log copies/mL). Further, viable SARS-CoV-2 was isolated from naso/oropharyngeal swabs and saliva of COVID-19 patients, as well as nasal washes of ferrets inoculated with patient urine or stool.

Discussion: Viable SARS-CoV-2 was demonstrated in saliva, urine and stool samples from COVID-19 patients up to days 11-15 of the clinical course. This result suggests that viable SARS-CoV-2 can be secreted in various clinical samples and respiratory specimens.
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http://dx.doi.org/10.1016/j.cmi.2020.07.020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7375961PMC
November 2020

Antiviral Efficacies of FDA-Approved Drugs against SARS-CoV-2 Infection in Ferrets.

mBio 2020 05 22;11(3). Epub 2020 May 22.

Department of Microbiology, Chungbuk National University College of Medicine and Medical Research Institute, Cheongju, Republic of Korea

Due to the urgent need of a therapeutic treatment for coronavirus (CoV) disease 2019 (COVID-19) patients, a number of FDA-approved/repurposed drugs have been suggested as antiviral candidates at clinics, without sufficient information. Furthermore, there have been extensive debates over antiviral candidates for their effectiveness and safety against severe acute respiratory syndrome CoV 2 (SARS-CoV-2), suggesting that rapid preclinical animal studies are required to identify potential antiviral candidates for human trials. To this end, the antiviral efficacies of lopinavir-ritonavir, hydroxychloroquine sulfate, and emtricitabine-tenofovir for SARS-CoV-2 infection were assessed in the ferret infection model. While the lopinavir-ritonavir-, hydroxychloroquine sulfate-, or emtricitabine-tenofovir-treated group exhibited lower overall clinical scores than the phosphate-buffered saline (PBS)-treated control group, the virus titers in nasal washes, stool specimens, and respiratory tissues were similar between all three antiviral-candidate-treated groups and the PBS-treated control group. Only the emtricitabine-tenofovir-treated group showed lower virus titers in nasal washes at 8 days postinfection (dpi) than the PBS-treated control group. To further explore the effect of immune suppression on viral infection and clinical outcome, ferrets were treated with azathioprine, an immunosuppressive drug. Compared to the PBS-treated control group, azathioprine-immunosuppressed ferrets exhibited a longer period of clinical illness, higher virus titers in nasal turbinate, delayed virus clearance, and significantly lower serum neutralization (SN) antibody titers. Taken together, all antiviral drugs tested marginally reduced the overall clinical scores of infected ferrets but did not significantly affect virus titers. Despite the potential discrepancy of drug efficacies between animals and humans, these preclinical ferret data should be highly informative to future therapeutic treatment of COVID-19 patients. The SARS-CoV-2 pandemic continues to spread worldwide, with rapidly increasing numbers of mortalities, placing increasing strain on health care systems. Despite serious public health concerns, no effective vaccines or therapeutics have been approved by regulatory agencies. In this study, we tested the FDA-approved drugs lopinavir-ritonavir, hydroxychloroquine sulfate, and emtricitabine-tenofovir against SARS-CoV-2 infection in a highly susceptible ferret infection model. While most of the drug treatments marginally reduced clinical symptoms, they did not reduce virus titers, with the exception of emtricitabine-tenofovir treatment, which led to diminished virus titers in nasal washes at 8 dpi. Further, the azathioprine-treated immunosuppressed ferrets showed delayed virus clearance and low SN titers, resulting in a prolonged infection. As several FDA-approved or repurposed drugs are being tested as antiviral candidates at clinics without sufficient information, rapid preclinical animal studies should proceed to identify therapeutic drug candidates with strong antiviral potential and high safety prior to a human efficacy trial.
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http://dx.doi.org/10.1128/mBio.01114-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7244896PMC
May 2020

Infection and Rapid Transmission of SARS-CoV-2 in Ferrets.

Cell Host Microbe 2020 05 6;27(5):704-709.e2. Epub 2020 Apr 6.

College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Republic of Korea; Zoonotic Infectious Diseases Research Center, Chungbuk National University, Cheongju, Republic of Korea. Electronic address:

The outbreak of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in China and rapidly spread worldwide. To prevent SARS-CoV-2 dissemination, understanding the in vivo characteristics of SARS-CoV-2 is a high priority. We report a ferret model of SARS-CoV-2 infection and transmission that recapitulates aspects of human disease. SARS-CoV-2-infected ferrets exhibit elevated body temperatures and virus replication. Although fatalities were not observed, SARS-CoV-2-infected ferrets shed virus in nasal washes, saliva, urine, and feces up to 8 days post-infection. At 2 days post-contact, SARS-CoV-2 was detected in all naive direct contact ferrets. Furthermore, a few naive indirect contact ferrets were positive for viral RNA, suggesting airborne transmission. Viral antigens were detected in nasal turbinate, trachea, lungs, and intestine with acute bronchiolitis present in infected lungs. Thus, ferrets represent an infection and transmission animal model of COVID-19 that may facilitate development of SARS-CoV-2 therapeutics and vaccines.
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http://dx.doi.org/10.1016/j.chom.2020.03.023DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7144857PMC
May 2020

Genetic and pathogenic diversity of severe fever with thrombocytopenia syndrome virus (SFTSV) in South Korea.

JCI Insight 2020 01 30;5(2). Epub 2020 Jan 30.

Department of Microbiology, College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Chungcheongbuk-do, South Korea.

To investigate nationwide severe fever with thrombocytopenia syndrome virus (SFTSV) infection status, we isolated SFTSVs from patients with suspected severe fever with thrombocytopenia syndrome (SFTS) in 207 hospitals throughout South Korea between 2013 and April 2017. A total of 116 SFTSVs were isolated from 3137 SFTS-suspected patients, with an overall 21.6% case fatality rate. Genetic characterization revealed that at least 6 genotypes of SFTSVs were co-circulating in South Korea, with multiple reassortments among them. Of these, the genotype B-2 strains were the most prevalent, followed by the A and F genotypes. Clinical and epidemiologic investigations revealed that genotype B strains were associated with the highest case fatality rate, while genotype A caused only one fatality among 10 patients. Further, ferret infection studies demonstrated varying clinical manifestations and case mortality rates with different strains of SFTSV, which suggests this virus could exhibit genotype-dependent pathogenicity.
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http://dx.doi.org/10.1172/jci.insight.129531DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7098714PMC
January 2020

A Novel Neuraminidase-Dependent Hemagglutinin Cleavage Mechanism Enables the Systemic Spread of an H7N6 Avian Influenza Virus.

mBio 2019 11 5;10(6). Epub 2019 Nov 5.

College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Republic of Korea

In this study, we demonstrate a novel mechanism for hemagglutinin (HA) activation in a naturally occurring H7N6 avian influenza A virus strain, A/mallard duck/Korea/6L/2007 (A/Mdk/6L/07). This novel mechanism allows for systemic infection of chickens, ducks, and mice, and A/Mdk/6L/07 can replicate without exogenous trypsin and exhibits broad tissue tropism in animals despite the presence of a monobasic HA cleavage motif (PEIPKGR/G). The trypsin-independent growth phenotype requires the N6 neuraminidase and the specific recognition of glycine at the P2 position of the HA cleavage motif by a thrombin-like protease. Correspondingly, viral growth is significantly attenuated by the addition of a thrombin-like protease inhibitor (argatroban). These data provide evidence for a previously unrecognized virus replication mechanism and support the hypothesis that thrombin-mediated HA cleavage is an important virulence marker and potential therapeutic target for H7 influenza viruses. The identification of virulence markers in influenza viruses underpins risk assessment programs and the development of novel therapeutics. The cleavage of the influenza virus HA is a required step in the viral life cycle, and phenotypic differences in viruses can be caused by changes in this process. Here, we describe a novel mechanism for HA cleavage in an H7N6 influenza virus isolated from a mallard duck. The mechanism requires the N6 protein and full activity of thrombin-like proteases and allows the virus to cause systemic infection in chickens, ducks, and mice. The thrombin-mediated cleavage of HA is thus a novel virulence determinant of avian influenza viruses.
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http://dx.doi.org/10.1128/mBio.02369-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6831776PMC
November 2019

Greater Efficacy of Black Ginseng (CJ EnerG) over Red Ginseng against Lethal Influenza A Virus Infection.

Nutrients 2019 Aug 13;11(8). Epub 2019 Aug 13.

College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju 28644, Korea.

Black ginseng (BG, CJ EnerG), prepared via nine repeated cycles of steaming and drying of fresh ginseng, contains more accessible acid polysaccharides and smaller and less polar ginsenosides than red ginseng (RG) processed only once. Because RG exhibits the ability to increase host protection against viral respiratory infections, we investigated the antiviral effects of BG. Mice were orally administered either BG or RG extract at 10 mg/kg bw daily for two weeks. Mice were then infected with a A(H1N1) pdm09 (A/California/04/2009) virus and fed extracts for an additional week. Untreated, infected mice were assigned to either the negative control, without treatments, or the positive control, treated with Tamiflu. Infected mice were monitored for 14 days to determine the survival rate. Lung tissues were evaluated for virus titer and by histological analyses. Cytokine levels were measured in bronchoalveolar lavage fluid. Mice treated with BG displayed a 100% survival rate against infection, while mice treated with RG had a 50% survival rate. Further, mice treated with BG had fewer accumulated inflammatory cells in bronchioles following viral infection than did mice treated with RG. BG also enhanced the levels of GM-CSF and IL-10 during the early and late stages of infection, respectively, compared to RG. Thus, BG may be useful as an alternative antiviral adjuvant to modulate immune responses to influenza A virus.
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http://dx.doi.org/10.3390/nu11081879DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6723933PMC
August 2019

Shedding and Transmission Modes of Severe Fever With Thrombocytopenia Syndrome Phlebovirus in a Ferret Model.

Open Forum Infect Dis 2019 Aug;6(8)

College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Republic of Korea.

Background: Although human-to-human transmission of severe fever with thrombocytopenia syndrome phlebovirus (SFTSV) via direct contact with body fluids has been reported, the role of specific body fluids from SFTSV-infected hosts has not been investigated in detail.

Methods: To demonstrate the virus transmission kinetics in SFTSV-infected hosts, we adapted the ferret infection model and evaluated the virus shedding periods, virus titers, and transmission modes from various specimens of infected ferrets.

Results: Large amounts of infectious SFTSV are shed through nasal discharge, saliva, and urine from SFTSV-infected ferrets. Virus could be detected from 2 dpi and persisted until 12 dpi in these specimens, compared with the relatively short virus-shedding period in sera. Further, transmission studies revealed that SFTSV can be transmitted to close direct and indirect contact naïve animals through various mediums, especially through contact with serum and urine. Further, ferrets contacted with human urine specimens from SFTSV-positive patients were successfully infected with SFTSV, suggesting that urine specimens could be a source of SFTSV infection in humans.

Conclusions: Our results demonstrate that the SFTSV can be shed in various body fluids for more than 12 days and that these specimens could be a source for direct or indirect transmission through close personal contact.
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http://dx.doi.org/10.1093/ofid/ofz309DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6677671PMC
August 2019

Rapid and simple colorimetric detection of multiple influenza viruses infecting humans using a reverse transcriptional loop-mediated isothermal amplification (RT-LAMP) diagnostic platform.

BMC Infect Dis 2019 Aug 1;19(1):676. Epub 2019 Aug 1.

Department of Microbiology, College of Medicine and Medical Research Institute, Chungbuk National University, Chungdae-ro 1, Seowon-Ku, Cheongju, 28644, Republic of Korea.

Background: In addition to seasonal influenza viruses recently circulating in humans, avian influenza viruses (AIVs) of H5N1, H5N6 and H7N9 subtypes have also emerged and demonstrated human infection abilities with high mortality rates. Although influenza viral infections are usually diagnosed using viral isolation and serological/molecular analyses, the cost, accessibility, and availability of these methods may limit their utility in various settings. The objective of this study was to develop and optimized a multiplex detection system for most influenza viruses currently infecting humans.

Methods: We developed and optimized a multiplex detection system for most influenza viruses currently infecting humans including two type B (both Victoria lineages and Yamagata lineages), H1N1, H3N2, H5N1, H5N6, and H7N9 using Reverse Transcriptional Loop-mediated Isothermal Amplification (RT-LAMP) technology coupled with a one-pot colorimetric visualization system to facilitate direct determination of results without additional steps. We also evaluated this multiplex RT-LAMP for clinical use using a total of 135 clinical and spiked samples (91 influenza viruses and 44 other human infectious viruses).

Results: We achieved rapid detection of seasonal influenza viruses (H1N1, H3N2, and Type B) and avian influenza viruses (H5N1, H5N6, H5N8 and H7N9) within an hour. The assay could detect influenza viruses with high sensitivity (i.e., from 100 to 0.1 viral genome copies), comparable to conventional RT-PCR-based approaches which would typically take several hours and require expensive equipment. This assay was capable of specifically detecting each influenza virus (Type B, H1N1, H3N2, H5N1, H5N6, H5N8 and H7N9) without cross-reactivity with other subtypes of AIVs or other human infectious viruses. Furthermore, 91 clinical and spiked samples confirmed by qRT-PCR were also detected by this multiplex RT-LAMP with 98.9% agreement. It was more sensitive than one-step RT-PCR approach (92.3%).

Conclusions: Results of this study suggest that our multiplex RT-LAMP assay may provide a rapid, sensitive, cost-effective, and reliable diagnostic method for identifying recent influenza viruses infecting humans, especially in locations without access to large platforms or sophisticated equipment.
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http://dx.doi.org/10.1186/s12879-019-4277-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6669974PMC
August 2019

Seroprevalence of Severe Fever with Thrombocytopenia Syndrome Phlebovirus in Domesticated Deer in South Korea.

Virol Sin 2019 Oct 25;34(5):501-507. Epub 2019 Jun 25.

Department of Microbiology, College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, 28644, Republic of Korea.

Severe fever with thrombocytopenia syndrome phlebovirus (SFTSV) has a wide host range. Not only has it been found in humans, but also in many wild and domesticated animals. The infection of breeding deer on farms is a particularly worrisome public health concern due to the large amount of human contact and the diverse use of deer products, including raw blood. To investigate the prevalence of breeding domesticated deer, we examined the SFTSV infection rate on deer farms in South Korea from 2015 to 2017. Of the 215 collected blood samples, 0.9% (2/215) were found to be positive for viral RNA by PCR, and sequence analysis showed the highest homology with the KADGH human isolate. Both SFTSV-specific recombinant N and Gn protein-based ELISAs revealed that 14.0% (30/215) and 7.9% (17/215) of collected blood specimens were positive for SFTSV antibody. These results demonstrate that the breeding farm deer are exposed to SFTSV and could be a potential infection source for humans through direct contact or consumption of byproducts.
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http://dx.doi.org/10.1007/s12250-019-00137-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6814664PMC
October 2019

Ferret animal model of severe fever with thrombocytopenia syndrome phlebovirus for human lethal infection and pathogenesis.

Nat Microbiol 2019 03 10;4(3):438-446. Epub 2018 Dec 10.

Department of Microbiology, College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Republic of Korea.

Severe fever with thrombocytopenia syndrome phlebovirus (SFTSV), listed in the most dangerous pathogens by the World Health Organization, has 12-30% fatality rates with a characteristic thrombocytopenia syndrome. With a majority of clinically diagnosed SFTSV patients older than ~50 years of age, age is a critical risk factor for SFTSV morbidity and mortality. Here, we report an age-dependent ferret model of SFTSV infection and pathogenesis that fully recapitulates the clinical manifestations of human infections. Whereas young adult ferrets (≤2 years of age) did not show any clinical symptoms and mortality, SFTSV-infected aged ferrets (≥4 years of age) demonstrated severe thrombocytopenia, reduced white blood cell counts and high fever with 93% mortality rate. Moreover, a significantly higher viral load was observed in aged ferrets. Transcriptome analysis of SFTSV-infected young ferrets revealed strong interferon-mediated anti-viral signalling, whereas inflammatory immune responses were markedly upregulated and persisted in aged ferrets. Thus, this immunocompetent age-dependent ferret model should be useful for anti-SFTSV therapy and vaccine development.
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http://dx.doi.org/10.1038/s41564-018-0317-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6548318PMC
March 2019

Preclinical evaluation of the efficacy of an H5N8 vaccine candidate (IDCDC-RG43A) in mouse and ferret models for pandemic preparedness.

Vaccine 2019 01 27;37(3):484-493. Epub 2018 Nov 27.

College of Veterinary Medicine, Chungnam National University, Daejeon, Republic of Korea. Electronic address:

Because H5N1 influenza viruses continuously threaten the public health, the WHO has prepared various clades of H5N1 mock-up vaccines as one of the measures for pandemic preparedness. The recent worldwide outbreak of H5Nx virus which belongs to clade 2.3.4.4 and of which H5N6 subtype belongs and already caused human infection also increases the need of pandemic vaccine for such novel emerging viruses. In this study, we evaluated the protective efficacy and immunogenicity of an egg-based and inactivated whole-virus H5N8 (IDCDC-RG43A) developed by CDC containing HA and NA gene of the parent virus A/gyrfalcon/Washington/41088-6/2014. Mice vaccinated two times elicited low to moderate antibody titer in varying amount of antigen doses against the homologous H5N8 vaccine virus and heterologous intra-clade 2.3.4.4 H5N6 (A/Sichuan/26221/2014) virus. Mice immunized with at least 3.0 µg/dose of IDCDC-RG43A with aluminum hydroxide adjuvant were completely protected from lethal challenge with the mouse-adapted H5N8 (A/Environment/Korea/ma468/2015, maH5N8) as well as cleared the viral replication in tissues including lung, brain, spleen, and kidney. Vaccinated ferrets induced high antibody titers against clade 2.3.4.4 H5N8/H5N6 viruses and the antibody showed high cross-reactivity to clade 2.2 H5N1 but not to clade 1 and 2.3.4 viruses as measured by hemagglutinin inhibition and serum neutralization assays. Furthermore, administration of the vaccine in ferrets resulted in attenuation of clinical disease signs and virus spread to peripheral organs including lung, spleen, and kidney from high dose challenge with maH5N8 virus. The protective and immunogenic characteristic of the candidate vaccine are essential attributes to be considered for further clinical trials as a pre-pandemic vaccine for a potential pandemic virus.
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http://dx.doi.org/10.1016/j.vaccine.2018.11.064DOI Listing
January 2019

Simple, Rapid and Sensitive Portable Molecular Diagnosis of SFTS Virus Using Reverse Transcriptional Loop-Mediated Isothermal Amplification (RT-LAMP).

J Microbiol Biotechnol 2018 Nov;28(11):1928-1936

Department of Microbiology, Chungbuk National University College of Medicine and Medical Research Institute, Cheongju 28644, Republic of Korea.

Recently, human infections caused by severe fever with thrombocytopenia syndrome virus (SFTSV), which can lead to fatality, have dramatically increased in East Asia. With the unavailability of vaccines or antiviral drugs to prevent and/or treat SFTSV infection, early rapid diagnosis is critical for prevention and control of the disease. Here, we report the development of a simple, rapid and sensitive portable detection method for SFTSV infection applying reverse transcription-loop mediated isothermal amplification (RT-LAMP) combined with one-pot colorimetric visualization and electro-free reaction platform. This method utilizes a pocket warmer to facilitate diagnosis in a resource-limited setting. Specific primers were designed to target the highly-conserved region of L gene of SFTSV. The detection limit of the RT-LAMP assay was approximately 10 viral genome copies from three different SFTSV strains. This assay exhibited comparable sensitivity to qRT-PCR and 10-fold more sensitivity than conventional RT-PCR, with a rapid detection time of 30 to 60 minutes. The RT-LAMP assay using SFTSV clinical specimens has demonstrated a similar detection rate to qRT-PCR and a higher detection rate compared to conventional RT-PCR. Moreover, there was no observed cross-reactive amplification of other human infectious viruses including Japanese Encephalitis Virus (JEV), Dengue, Enterovirus, Zika, Influenza and Middle East Respiratory Syndrome Coronavirus (MERS-CoV). This highly sensitive, electro- and equipment-free rapid colorimetric visualization method is feasible for resource-limited SFTSV field diagnosis.
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http://dx.doi.org/10.4014/jmb.1806.06016DOI Listing
November 2018

Genome-Wide Identification and Expression Analyses of the Fibrillin Family Genes Suggest Their Involvement in Photoprotection in Cucumber.

Plants (Basel) 2018 Jun 27;7(3). Epub 2018 Jun 27.

Department of Bioindustry and Bioresource Engineering, Plant Engineering Research Institute, Sejong University, Seoul 05006, Korea.

Fibrillin (FBN) is a plastid lipid-associated protein found in photosynthetic organisms from cyanobacteria to plants. In this study, 10 genes were identified in genomic DNA sequences of cucumber (Chinese long and Gy14) through database searches using the conserved domain of FBN and the 14 genes of Arabidopsis. Phylogenetic analysis of CsaFBN protein sequences showed that there was no counterpart of Arabidopsis and rice FBN5 in the cucumber genome. FBN5 is essential for growth in Arabidopsis and rice; its absence in cucumber may be because of incomplete genome sequences or that another FBN carries out its functions. Among the 10 genes, and were the most divergent in terms of nucleotide sequences. Most of the genes were expressed in the leaf, stem and fruit. showed the highest mRNA expression levels in various tissues, followed by , and . High-light stress combined with low temperature decreased photosynthetic efficiency and highly induced transcript levels of , and , which decreased after 24 h treatment. Transcript levels of the other seven genes were changed only slightly. This result suggests that CsaFBN1, CsaFBN6 and CsaFBN11 may be involved in photoprotection under high-light conditions at low temperature.
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http://dx.doi.org/10.3390/plants7030050DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6161074PMC
June 2018

Seroprevalence and genetic characterization of severe fever with thrombocytopenia syndrome virus in domestic goats in South Korea.

Ticks Tick Borne Dis 2018 07 2;9(5):1202-1206. Epub 2018 May 2.

Department of Microbiology, College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Republic of Korea; Zoonotic Infectious Diseases Research Center, Chungbuk National University, Cheongju, Republic of Korea. Electronic address:

Severe fever with thrombocytopenia syndrome (SFTS) is a newly emerging tick-borne infectious disease caused by the SFTS virus (SFTSV). To investigate the prevalence of SFTSV in domestic goats in South Korea, we collected blood samples in commercial slaughterhouses in Chungbuk Province in 2017. Of the 207 samples tested, 4 (2%) were found to be positive for viral RNA by RT-PCR and 30 (14.4%) were positive for SFTSV antibody as detected by a nucleocapsid (NP) protein-based ELISA. Phylogenetic analysis of the non-structural protein (NS) sequences showed that all viruses belonged to the genotype B, although they were clustered into two different sublineages that showed the highest homology with the KR612076-JP01 and KY789441-CB3 human isolate from South Korea. Further, we confirmed the specificity of seropositive goat sera by FRNT and western blotting analysis and found differential cross-reactivity of the sera with genotype A and B SFTSV strains. Collectively, this study suggests that relatively high numbers of goats are infected by antigenically different SFTSV strains, which might have a potential for zoonotic infection.
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http://dx.doi.org/10.1016/j.ttbdis.2018.05.001DOI Listing
July 2018

Generation of a High-Growth Influenza Vaccine Strain in MDCK Cells for Vaccine Preparedness.

J Microbiol Biotechnol 2018 Jun;28(6):997-1006

Microbiology Department, College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju 28644, Republic of Korea.

As shown during the 2009 pandemic H1N1 (A(H1N1)pdm09) outbreak, egg-based influenza vaccine production technology is insufficient to meet global demands during an influenza pandemic. Therefore, there is a need to adapt cell culture-derived vaccine technology using suspended cell lines for more rapid and larger-scale vaccine production. In this study, we attempted to generate a high-growth influenza vaccine strain in MDCK cells using an A/Puerto/8/1934 (H1N1) vaccine seed strain. Following 48 serial passages with four rounds of virus plaque purification in MDCK cells, we were able to select several MDCK-adapted plaques that could grow over 10⁸ PFU/ml. Genetic characterization revealed that these viruses mainly had amino acid substitutions in internal genes and exhibited higher polymerase activities. By using a series of Rg viruses, we demonstrated the essential residues of each gene and identified a set of high-growth strains in MDCK cells (PB1, M1, and NS1). In addition, we confirmed that in the context of the high-growth A/PR/8/34 backbone, A/California/7/2009 (H1N1), A/Perth/16/2009 (H3N2), and A/environment/Korea/deltaW150/2006 (H5N1) also showed significantly enhanced growth properties (more than 10⁷ PFU/ml) in both attached- and suspended-MDCK cells compared with each representative virus and the original PR8 vaccine strain. Taken together, this study demonstrates the feasibility of a cell culture-derived approach to produce seed viruses for influenza vaccines that are cheap and can be grown promptly and vigorously as a substitute for egg-based vaccines. Thus, our results suggest that MDCK cell-based vaccine production is a feasible option for producing large-scale vaccines in case of pandemic outbreaks.
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http://dx.doi.org/10.4014/jmb.1712.12007DOI Listing
June 2018

Comparison of the pathogenic potential of highly pathogenic avian influenza (HPAI) H5N6, and H5N8 viruses isolated in South Korea during the 2016-2017 winter season.

Emerg Microbes Infect 2018 Mar 14;7(1):29. Epub 2018 Mar 14.

College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, KS001, Korea.

Highly pathogenic avian influenza (HPAI) A(H5N6) and A(H5N8) virus infections resulted in the culling of more than 37 million poultry in the Republic of Korea during the 2016/17 winter season. Here we characterize two representative viruses, A/Environment/Korea/W541/2016 [Em/W541(H5N6)] and A/Common Teal/Korea/W555/2017 [CT/W555(H5N8)], and evaluate their zoonotic potential in various animal models. Both Em/W541(H5N6) and CT /W555(H5N8) are novel reassortants derived from various gene pools of wild bird viruses present in migratory waterfowl arising from eastern China. Despite strong preferential binding to avian virus-type receptors, the viruses were able to grow in human respiratory tract tissues. Em/W541(H5N6) was found to be highly pathogenic in both chickens and ducks, while CT/W555(H5N8) caused lethal infections in chickens but did not induce remarkable clinical illness in ducks. In mice, both viruses appeared to be moderately pathogenic and displayed limited tissue tropism relative to HPAI H5N1 viruses. Em/W541(H5N6) replicated to moderate levels in the upper respiratory tract of ferrets and was detected in the lungs, brain, spleen, liver, and colon. Unexpectedly, two of three ferrets in direct contact with Em/W541(H5N6)-infected animals shed virus and seroconverted at 14 dpi. CT/W555(H5N8) was less pathogenic than the H5N6 virus in ferrets and no transmission was detected. Given the co-circulation of different, phenotypically distinct, subtypes of HPAI H5Nx viruses for the first time in South Korea, detailed virologic investigations are imperative given the capacity of these viruses to evolve and cause human infections.
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http://dx.doi.org/10.1038/s41426-018-0029-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5849756PMC
March 2018
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