• Molecules and Cells
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• v.45 no.10
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• pp.702-717
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• 2022

Hepatitis C virus (HCV) infection can lead to chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. HCV employs diverse strategies to evade host antiviral innate immune responses to mediate a persistent infection. In the present study, we show that nonstructural protein 5A (NS5A) interacts with an NF-κB inhibitor immunomodulatory kinase, IKKε, and subsequently downregulates beta interferon (IFN-β) promoter activity. We further demonstrate that NS5A inhibits DDX3-mediated IKKε and interferon regulatory factor 3 (IRF3) phosphorylation. We also note that hyperphosphorylation of NS5A mediates protein interplay between NS5A and IKKε, thereby contributing to NS5A mediated modulation of IFN-β signaling. Lastly, NS5A inhibits IKKε-dependent p65 phosphorylation and NF-κB activation. Based on these findings, we propose NS5A as a novel regulator of IFN signaling events, specifically by inhibiting IKKε downstream signaling cascades through its interaction with IKKε. Taken together, these data suggest an additional mechanistic means by which HCV modulates host antiviral innate immune responses to promote persistent viral infection.

• The Journal of Korean Society of Virology
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• v.28 no.2
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• pp.175-182
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• 1998

We investigated the rate of hepatitis G virus infection among 50 patients who were not infected with the hepatitis C virus but showed symptoms of hepatitis. Viral RNA was extracted from the patients' sera and cDNA was synthesized and amplified by RT-PCR (reverse transcription-polymerase chain reaction) using random hexamer and 5 primers (470-20-1-77F, 470-20-1-211R, 470-20-1-211R-biotin, GV57-4512MF, GV57-4657MR). The amplified PCR products were confirmed by electrochemiluminescence (ECL), liquid hybridization (LH) and Southern blotting (SB). Among the 50 PCR products, by means of ECL, we found 4 samples to be positive and 5 samples to be indeterminate. The GV45-89M probe (5'-CYCGCTGRTITGGGGTGTACfGGAAGGC-3') was end-labelled with gamma-$^{32}P$ ATP and used for liquid hybridization with the PCR products. By using liquid hybridization, we detected specific bands from 4 positive sera and also from one indeterminate serum as determined by ECL. An 1.5% agarose gel electrophoresis of the 9 PCR products which were HGV positive or indeterminate as determined by ECL showed a 160bp band from 4 positive and one indeterminate serum. The 5 PCR products proved to be positive when SB was applied with the GV45-89M probe as well as when LH was applied. LH and SB were shown to have higher sensitivity and specificity than ECL. Two cases among 5 positive cases had relatively high SGOT, SGPT, ALP values when compared with other 48 cases. In summary, we confirmed hepatitis G virus infection in 5 cases among 50 Korean patients showing symptoms of viral hepatitis.

• Mycobiology
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• v.29 no.2
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• pp.65-72
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• 2001

• Korean Journal of Ichthyology
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• v.28 no.3
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• pp.141-146
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• 2016

Experimental infection of rainbow trout Oncorhynchus mykiss with viral hemorrhagic septicemia virus (VHSV, genotype IVa) from olive flounder Paralichtys olivaceus was examined. The cumulative mortalities of three different lot of rainbow trout fry challenged with VHSV ($10^{6.3-7.3}TCID_{50}$/fish) were less than 15%. No difference of virulence was observed in experimental infection using 5 in vivo passaged VHSV and original VHSV. No mortality was observed in seawater-reared rainbow trout (adult) challenged with VHSV ($10^{5.3-6.3}TCID_{50}$/fish) and virus was not detected in the fish. We thus concluded that VHSV from olive flounder has low virulence to rainbow trout fry, but not pathogenic to seawater-rainbow trout (adult).

• Research in Plant Disease
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• v.19 no.3
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• pp.233-236
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• 2013

This research was conducted to investigate the incidence of viral infection in Samcheok-shi and Jeongseon-gun, main garlic growing areas of Gangwon province in Korea. Four primers sets (GLV, LYSV, GCLV, OYDV) were used for RT-PCR to test of 100 samples collected from each location. Infection rates of GLV, LYSV, GCLV and OYDV of garlic samples from Samcheok-shi and Jeongseon-gun were 95, 95, 92 and 33%, respectively. All garlic samples tested in this research were infected at least one virus. Coinfection of 3 kinds of virus (GLV, LYSV and GCLV) and 4 kinds of virus (GLV, LYSV, GCLV and OYDV) were 60 and 25%, respectively. While infections of GLV, LYSV and GCLV were evenly found in both two regions, OYDV infection of garlic samples collected from Jeongseon-gun was higher than Samcheok-shi. Viral infections at garlic fields of whole country and Gangwon province are very serious now. Therefore, it is very necessary to develop technic for virus-free bulb and renew seed bulb of garlic.

• Korean Journal of Veterinary Research
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• v.58 no.1
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• pp.9-16
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• 2018

A preliminary study into the protective mechanisms of adaptive immunity against porcine reproductive and respiratory syndrome virus (PRRSV) in piglets (n = 9) born to a gilt challenged intranasally with a type-2 PRRSV. Immune parameters (neutralizing antibodies, $CD3^+CD4^+$, $CD3^+CD8^+$, $CD3^+CD4^+CD8^+$ T-lymphocytes, and PRRSV-specific interferon $(IFN)-{\gamma}$ secreting T-lymphocytes) were compared with infection parameters (macro- and microscopic lung lesion, and PRRSV-infected porcine alveolar macrophages ($CD172{\alpha}^+PRRSV-N^+\;PAM$) as well as with plasma and lymphoid tissue viral loads. Percentages of three T-lymphocyte phenotypes in 14-days post-birth (dpb) peripheral blood mononuclear cell (PBMC) had significant negative correlations with percentages of $CD172{\alpha}^+PRRSV-N^+\;PAM$ (p < 0.05) as well as with macroscopic lung lesion (p < 0.01). Plasma and tissue viral loads had significant (p < 0.05) negative correlations with $CD3^+CD4^+CD8^+$ T-lymphocyte percentage in PBMC. Frequencies of $CD3^+CD8^+$ and $CD3^+CD4^+$ T-lymphocytes in 14-dpb PBMC had significant negative correlations with of lymph node (p = 0.04) and lung (p = 0.002) viral loads. $IFN-{\gamma}$-secreting T-lymphocytes frequency had a significant negative correlation with gross lung lesion severity (p = 0.002). However, neutralizing antibody titers had no significant negative correlation (p > 0.1) with infection parameters. The results indicate that T-lymphocytes contribute to controlling PRRSV replication in young piglets born after in-utero infection.

• The Plant Pathology Journal
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• v.32 no.5
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• pp.377-387
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• 2016

Tomato yellow leaf curl virus (TYLCV), a member of the genus Begomovirus, is one of the most important viruses of cultivated tomatoes worldwide, mainly causing yellowing and curling of leaves with stunting in plants. TYLCV causes severe problems in sub-tropical and tropical countries, as well as in Korea. However, the mechanism of TYLCV infection remains unclear, although the function of each viral component has been identified. TYLCV C4 codes for a small protein involved in various cellular functions, including symptom determination, gene silencing, viral movement, and induction of the plant defense response. In this study, through yeast-two hybrid screenings, we identified TYLCV C4-interacting host proteins from both healthy and symptom-exhibiting tomato tissues, to determine the role of TYLCV C4 proteins in the infection processes. Comparative analyses of 28 proteins from healthy tissues and 36 from infected tissues showing interactions with TYLCV C4 indicated that TYLCV C4 mainly interacts with host proteins involved in translation, ubiquitination, and plant defense, and most interacting proteins differed between the two tissues but belong to similar molecular functional categories. Four proteins-two ribosomal proteins, S-adenosyl-L-homocysteine hydrolase, and 14-3-3 family protein-were detected in both tissues. Furthermore, the identified proteins in symptom-exhibiting tissues showed greater involvement in plant defenses. Some are key regulators, such as receptor-like kinases and pathogenesis-related proteins, of plant defenses. Thus, TYLCV C4 may contribute to the suppression of host defense during TYLCV infection and be involved in ubiquitination for viral infection.

• Korean Journal of Veterinary Service
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• v.47 no.2
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• pp.73-79
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• 2024

Bovine viral diarrhea virus (BVDV) is distributed in cattle worldwide and causes significant economic losses to the livestock industry. Identification and remove of BVDV persistently infected (PI) cattle is very important to control BVDV infection in cattle herd. The objective of this study is to investigate the infection status of BVDV infection in Korean native cattle (Bos taurus coreanae) farms located in Jeonbuk State. From 2021 to 2022, a total of 1,497 samples were collected from 17 cattle farms and tested for BVDV antigen using a commercial ELISA kit. By the first ELISA testing, 24 cattle from six farms were positive for BVDV antigen, showing the farm-level or cattle-level prevalence of 35.3% or 1.6%, respectively. By the second ELISA testing which carried out with the first ELISA-positive samples after three-weeks, 12 cattle (0.8%) from five farms (29.4%) were positive for BVDV antigen, indicating these cattle were PI cattle. Genotypes of BVDV were determined with 12 BVDV-positive samples using a previously described RT-PCR assay and the results showed that 3 (25.0%) and 9 (75.0%) were confirmed to be type 1 and type 2, respectively. These results will be helpful to establish the effective control strategy for BVDV in cattle farms in Jeonbuk State.

• BMB Reports
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• v.42 no.12
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• pp.776-787
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• 2009

T helper (Th) 17 cells have recently been described as a third subset of T helper cells, and have provided new insights into the mechanisms that are important in the development of autoimmune diseases and the immune responses that are essential for effective antimicrobial host defense. Both protective and harmful effects of Th17 responses during infection have been described. In general, Th17 responses are critical for mucosal and epithelial host defense against extracellular bacteria and fungi. However, recent studies have reported that Th17 responses can also contribute to viral persistence and chronic inflammation associated with parasitic infection. It has become evident that the type of microorganisms and the setting in which they trigger the Th17 response determines the outcome of the delicate balancethat exists between Th17 induced protection and immunopathogenesis.

• The Plant Pathology Journal
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• v.26 no.2
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• pp.194-197
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• 2010

Most orchids are propagated by tissue culture. To survey the viral infection of tissue cultured Orchids, total RNA was extracted from in vitro Cymbridium and Phalaenopsis spp. collected from companies producing tissue-cultured orchids, and RT-PCR analysis was conducted with primer pairs specific to Cymbidium mosaic virus (CymMV) and Odontoglossum ring spot virus(ORSV), which are infecting wide range of orchid genera. The bulb size of Cymbidium infected with CymMV and ORSV was compared with healthy one at 10 months after planting in vitro orchids in the glasshouse. The CymMV or ORSV infection in 97 Cymbidium and 55 Phalaenopsis plants was 84.5 and 89.1 %, respectively. Mixed infection was found in 52.6 and 47.3% of Cymbidium and Phalaenopsis tested, whereas virus-free orchids were 15.5 and 10.9%, respectively. The CymMV and ORSV reduced the bulb size by 2.7-50% depending on the cultivars of Cymbidium. The both viruses caused yellowing, mottle and mosaic with or without necrosis in 4 Cymbidium cultivars.