• Journal of Microbiology and Biotechnology
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• v.26 no.6
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• pp.1109-1114
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• 2016

H3N2 canine influenza virus emerged in South Korea in 2007 and subsequently spread to China and Thailand, causing epidemic or endemic respiratory diseases in dogs. Through intermammalian species transmission, the virus has also infected cats. However, no direct evidence of significant genetic evolution has been reported since its first emergence. Here, we describe in depth the genetic and molecular characteristics of the ancestral strain (i.e., the first virus isolate from South Korea) of the H3N2 canine influenza virus currently circulating in East Asia.

• Korean Journal of Veterinary Research
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• v.42 no.4
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• pp.523-529
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• 2002

A Total of 703 swine sera from 55 swine farrns (Mar. 1998 through Feb. 2001) were nation-wide collected for the presence of the antibody to influenza A virus H3 subtype isolate. The presence of antibody was tested by hernagglutination inhibition with chicken red blood cells and seropositiveness was determined by HI titer ${\geq}1$: 40. Sero-prevalence was evaluated based on year, season, region and age, respectively. In consequence, there were seme differences by year, season and region, respectively. High susceptibility was routinely observed in 60 and 90 day-old piglets. Therefore, it seems that the sero-prevalence to swine influenza virus H3 subtype isolate is useful for the prevention and control of swine influenza in Korea.

• Genomics & Informatics
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• v.20 no.4
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• pp.46.1-46.7
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• 2022

Influenza A virus (IAV) is the most widespread pathogen causing human respiratory infections. Although polymerase chain reaction (PCR)-based methods are currently the most commonly used tools for IAV detection, PCR is not ideal for point-of-care testing. In this study, we aimed to develop a more rapid and sensitive method than PCR-based tools to detect IAV using loop-mediated isothermal amplification (LAMP) technology. We designed reverse-transcriptional (RT)-LAMP primers targeting the hemagglutinin gene. RNAs from reference H1N1 and H3N2 showed specific RT-LAMP signals with the designed primers. We optimized the reaction conditions and developed universal reaction conditions for both LAMP assays. Under these conditions, the detection limit was 50 copies for both RT-LAMP assays. There was no non-specific signal to 19 non-IAV respiratory viruses, such as influenza B virus, coronaviruses, and respiratory syncytial viruses. Regarding the reaction time, a positive signal was detected within 25 min after starting the reaction. In conclusion, our RT-LAMP assay has high sensitivity and specificity for the detection of the H1 and H3 subtypes, making it suitable for point-of-care IAV testing.

• Journal of Microbiology and Biotechnology
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• v.26 no.11
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• pp.1972-1982
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• 2016

Influenza A virus is a single-stranded RNA virus with a genome of negative polarity. Owing to the antigenic diversity and cross concrete shift, an immense number of novel strains have developed astronomically over the years. The present work deals with the codon utilization partialness among five different influenza A viruses isolated from human hosts. All the subtypes showed the homogeneous pattern of nucleotide utilization with a little variation in their utilization frequencies. A lower bias in codon utilization was observed in all the subtypes as reflected by higher magnitudes of an efficacious number of codons. Dinucleotide analysis showed very low CpG utilization and a high predilection of A/T-ending codons. The H5N1 subtype showed noticeable deviation from the rest. Codon pair context analysis showed remarkable depletion of NNC-GNN and NNT-ANN contexts. The findings alluded towards GC-compositional partialness playing a vital role, which is reflected in the consequential positive correlation between the GC contents at different codon positions. Untangling the codon utilization profile would significantly contribute to identifying novel drug targets that will pacify the search for antivirals against this virus.

• Journal of Microbiology and Biotechnology
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• v.21 no.5
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• pp.449-454
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• 2011

The infection of pandemic influenza viruses such as swine flu (H1N1) and avian flu viruses to the host cells is related to the following two factors: First, the surface protein such as HA (hemagglutinin) and NA (neuraminidase) of the influenza virus. Second, the specific structure of the oligosaccharide [sialic acid(${\alpha}2$-6) galactose(${\beta}1$-4)glucose or sialic acid(${\alpha}2$-3)galactose(${\beta}1$-4)glucose] on the host cell. After recognizing the specific structure of the oligosaccharide on the surface of host cells by the surface protein of the influenza virus, the influenza virus can secrete sialidase and cleave the sialic acid attached on the final position of the specific structure of the oligosaccharide on the surface of host cells. Tamiflu (oseltamivir), known as a remedy of swine flu, has a saccharide analog structure, especially the sialic acid analog. Tamiflu can inhibit the invasion of influenza viruses (swine flu and avian flu viruses) into the host cells by competition with sialic acid on the terminal position of the specific oligosaccharide on the surface of the host cell. Because of the emergence of Tamiflu resistance, the development of new potent anti-influenza inhibitors is needed. The inhibitors with positive-charge groups have potential as antiviral therapeutics, and the strain specificity must also be resolved.

• Korean Journal of Veterinary Research
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• v.59 no.3
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• pp.151-155
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• 2019

Equine influenza (EI) is the main cause of respiratory illness in equines across the globe and is caused by equine influenza A virus (EIV-A), which has impacted the equine industry internationally because of the marginal mortality and high morbidity. In the present study, the immune responses after equine influenza vaccination were evaluated in 4,144 horses in Korea using the hemagglutination inhibition (HI) assay. The equine influenza virus (EIV), A/equine/South Africa/4/03 (H3N8), was used as the antigen in the HI assay. The mean seropositive rates were 89.2% (97.4% in 2016, 77.6% in 2017, and 92.4% in 2018). This paper highlights the advances in understanding the effects of vaccines and control strategies for mitigating the emerging menace by EIV.

• IMMUNE NETWORK
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• v.16 no.5
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• pp.311-315
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• 2016

A pandemic influenza A (H1N1) virus strain was isolated from a pig farm in Korea in December 2009. The strain was propagated in and isolated from both the Madin-Darby canine kidney cell line and embryonated eggs. The partial and complete sequences of the strain were identical to those of A/California/04/2009, with >99% sequence similarity in the HA, NA, M, NS, NP, PA, PB1, and PB2 genes. The isolated strain was inactivated and used to prepare a swine influenza vaccine. This trial vaccine, containing the new isolate that has high sequence similarity with the pandemic influenza A (H1N1) virus, resulted in seroconversion in Guinea pigs and piglets. This strain could therefore be a potential vaccine candidate for swine influenza control in commercial farms.

• Food Science of Animal Resources
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• v.30 no.2
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• pp.345-350
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• 2010

Various extracts from 30 medicinal plants were evaluated for their antiviral activity against influenza virus A/Puerto Rico/8/34 (H1N1) and cytotoxicity in MDCK cell culture. The plant material (30 g) was extracted with methanol (300 mL) at room temperature for 24 h, after which the methanolic extracts were filtered, evaporated, and subsequently lyophilized. Evaluation of the potential antiviral activity was conducted by a viral replication inhibition test. Among these medicinal plants, Tussilago farfara, Brassica juncea, Prunus armeniaca, Astragalus membranaceus, Patrinia villosa, and Citrus unshiu showed marked antiviral activity against influenza virus A/H1N1 at concentrations ranging from 0.15625 mg/mL to 1.25 mg/mL, 0.3125 mg/mL to 10 mg/mL, 5 mg/mL to 10 mg/mL, 0.625 mg/mL to 10 mg/mL, 0.625 mg/mL to 10 mg/mL, and 0.3125 mg/mL to 5 mg/mL, respectively. The extracts of Tussilago farfara showed cytotoxicity at concentrations greater than 2.5 mg/mL, whereas the other five main extracts showed no cytotoxicity at concentrations of 10 mg/mL. Taken together, the present results indicated that methanolic extracts of the six main plants might be useful for the treatment of influenza virus H1N1.

• Journal of the korean veterinary medical association
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• v.43 no.6
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• pp.536-542
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• 2007

국내뿐만 아니라, 전세계적으로 관심을 가지고 있는 인플루엔자 바이러스(influenza virus)는 일반적으로 고열과 기침을 동반한 독감을 일으키는 원인체로서, 사람을 포함한 포유동물과 조류 등에 감염되고 전염될 수 있기 때문에 많은 문제를 유발 하고 있습니다. 또한 이미 많이 알려진 조류 인플루엔자(avain influenza; AI)의 경우 조류에서 뿐만 아니라, 사람에게 전염될 경우 치명적인 결과를 초래하는 경우가 많아 때로는 공포의 대상이 되기도 합니다. 더욱이 조류 인플루엔자(AI)는 보건상의 문제를 해결하기 위해 많은 노력을 기울이고 있음에도 불구하고, 현재까지도 국내.외 여러 산업에 영향을 주거나 사람이 사망에 까지 이르고 있는 실정입니다. 이러한 현실에서 인플루엔자 바이러스가 사람을 비롯한 여러 동물에서 감염 혹은 전염이 확인될 경우 많은 걱정을 할 수 밖에 없으며, 만약 동물에서의 바이러스 감염 사실이 과장되거나 잘못된 정보가 대중에게 알려질 경우에는 사회적으로 엄청난 파장을 일으킬 수 밖에 없는 것이 현실입니다. 더욱이, 근래 미국에서는 개의 독감(canine flu)이라고 불리는 개의 인플루엔자 바이러스(canine influenza virus; CIV) 감염이 전역으로 확산되고 있는 상황이기 때문에, 국내에서도 예의주시하면서 지켜보고 있을 뿐만 아니라, 수의사를 비롯한 보호자를 개의 인플루엔자 바이러스에 대해서 많은 관심을 가지고 있는 상황입니다.

• IMMUNE NETWORK
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• v.21 no.4
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• pp.28.1-28.14
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• 2021

Lung-resident memory T cells (T_RM) play an essential role in protecting against pulmonary virus infection. Parenteral administration of DNA vaccine is generally not sufficient to induce lung CD8 T_RM cells. This study investigates whether intramuscularly administered DNA vaccine expressing the nucleoprotein (NP) induces lung T_RM cells and protects against the influenza B virus. The results show that DNA vaccination poorly generates lung T_RM cells and massive secondary effector CD8 T cells entering the lungs after challenge infection do not offer sufficient protection. Nonetheless, intranasal administration of non-replicating adenovirus vector expressing no Ag following priming DNA vaccination deploys NP-specific CD8 T_RM cells in the lungs, which subsequently offers complete protection. This novel 'prime and deploy' strategy could be a promising regimen for a universal influenza vaccine targeting the conserved NP Ag.