• Molecules and Cells
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• 제44권6호
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• pp.401-407
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• 2021

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19), which is an ongoing pandemic disease. SARS-CoV-2-specific CD4⁺ and CD8⁺ T-cell responses have been detected and characterized not only in COVID-19 patients and convalescents, but also unexposed individuals. Here, we review the phenotypes and functions of SARS-CoV-2-specific T cells in COVID-19 patients and the relationships between SARS-CoV-2-specific T-cell responses and COVID-19 severity. In addition, we describe the phenotypes and functions of SARS-CoV-2-specific memory T cells after recovery from COVID-19 and discuss the presence of SARS-CoV-2-reactive T cells in unexposed individuals and SARS-CoV-2-specific T-cell responses elicited by COVID-19 vaccines. A better understanding of T-cell responses is important for effective control of the current COVID-19 pandemic.

• Nutrition Research and Practice
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• 제11권1호
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• pp.11-16
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• 2017

BACKGROUND/OBJECTIVES: Helicobacter pylori (H. pylori) colonization of the stomach mucosa and duodenum is the major cause of acute and chronic gastroduodenal pathology in humans. Efforts to find effective anti-bacterial strategies against H. pylori for the non-antibiotic control of H. pylori infection are urgently required. In this study, we used whey to prepare glycomacropeptide (GMP), from which sialic acid (G-SA) was enzymatically isolated. We investigated the anti-bacterial effects of G-SA against H. pylori in vitro and in an H. pylori-infected murine model. MATERIALS/METHODS: The anti-bacterial activity of G-SA was measured in vitro using the macrodilution method, and interleukin-8 (IL-8) production was measured in H. pylori and AGS cell co-cultures by ELISA. For in vivo study, G-SA 5 g/kg body weight (bw)/day and H. pylori were administered to mice three times over one week. After one week, G-SA 5 g/kg bw/day alone was administered every day for one week. Tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), IL-$1{\beta}$, IL-6, and IL-10 levels were measured by ELISA to determine the anti-inflammatory effects of G-SA. In addition, real-time PCR was performed to measure the genetic expression of cytotoxin-associated gene A (cagA). RESULTS: G-SA inhibited the growth of H. pylori and suppressed IL-8 production in H. pylori and in AGS cell co-cultures in vitro. In the in vivo assay, administration of G-SA reduced levels of IL-$1{\beta}$ and IL-6 pro-inflammatory cytokines whereas IL-10 level increased. Also, G-SA suppressed the expression of cagA in the stomach of H. pylori-infected mice. CONCLUSION: G-SA possesses anti-H. pylori activity as well as an anti-H. pylori-induced gastric inflammatory effect in an experimental H. pylori-infected murine model. G-SA has potential as an alternative to antibiotics for the prevention of H. pylori infection and H. pylori-induced gastric disease prevention.

• IMMUNE NETWORK
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• 제7권4호
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• pp.186-196
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• 2007

Background: Although IL-12 has been widely accepted to playa central role in the control of pathogen infection, the use of recombinant IL-12 (rIL-12) as a vaccine adjuvant has been known to be ineffective because of its rapid clearance in the body. Methods: To investigate the effect of sustained release of IL-12 in vivo in the peptide and protein vaccination models, rIL-12 was encapsulated into poly ($A_{DL}$-lactic-co-glycolic acid) (PLGA). Results: We found that codelivery of IL-12-encapsulated microspheres (IL-12EM) could dramatically increase not only antibody responses, but also antigen-specific $CD4^+\;and\;CD8^+$ T cell responses. Enhanced immune responses were shown to be correlated with protective immunity against influenza and respiratory syncytial virus (RSV) virus challenge. Interestingly, the enhancement of $CD8^+$ T cell response was not detectable when $CD4^+$ T cell knockout mice were subjected to vaccination, indicating that the enhancement of the $CD8^+$ T cell response by IL-12EM is dependent on $CD4^+$ T cell "help". Conclusion: Thus, IL-12EM could be applied as an adjuvant of protein and peptide vaccines to enhance protective immunity against virus infection.

• Clinical and Experimental Pediatrics
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• 제64권12호
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• pp.652-660
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• 2021

Background: Viral load and shedding duration are highly associated with the transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. However, limited studies have reported on viral load or shedding in children and adolescents infected with sudden acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Purpose: This study aimed to investigate the natural course of viral load in asymptomatic or mild pediatric cases. Methods: Thirty-one children (<18 years) with confirmed SARS-CoV-2 infection were hospitalized and enrolled in this study. Viral loads were evaluated in nasopharyngeal swab samples using real-time reverse transcription polymerase chain reaction (E, RdRp, N genes). cycle threshold (Ct) values were measured when patients met the clinical criteria to be released from quarantine. Results: The mean age of the patients was 9.8 years, 18 (58%) had mild disease, and 13 (42%) were asymptomatic. Most children were infected by adult family members, most commonly by their mothers. The most common symptoms were fever and sputum (26%), followed by cough and runny nose. Nine patients (29%) had a high or intermediate viral load (Ct value≤30) when they had no clinical symptoms. Viral load showed no difference between symptomatic and asymptomatic patients. Viral rebounds were found in 15 cases (48%), which contributed to prolonged viral detection. The mean duration of viral detection was 25.6 days. Viral loads were significantly lower in patients with viral rebounds than in those with no rebound (E, P=0.003; RdRp, P=0.01; N, P=0.02). Conclusion: Our study showed that many pediatric patients with coronavirus disease 2019 (COVID-19) experienced viral rebound and showed viral detection for more than 3 weeks. Further studies are needed to investigate the relationship between viral rebound and infectiousness in COVID-19.

• The Plant Pathology Journal
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• 제30권4호
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• pp.407-415
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• 2014

Viral diseases have been a major limiting factor threating sustainable potato (Solanum tuberosum L.) production in Pakistan. Surveys were conducted to serologically quantify the incidence of RNA viruses infecting potato; Potato virus X (PVX), Potato virus Y (PVY), Potato virus S (PVS), Potato virus A (PVA), Potato virus M (PVM) and Potato leaf roll virus (PLRV) in two major potato cultivars (Desiree and Cardinal). The results suggest the prevalence of multiple viruses in all surveyed areas with PVY, PVS and PVX dominantly widespread with infection levels of up to 50% in some regions. Co-infections were detected with the highest incidence (15.5%) for PVX and PVS. Additionally the data showed a positive correlation between co-infecting viruses with significant increase in absorbance value (virus titre) for at least one of the virus in an infected plant and suggested a synergistic interaction. To test this hypothesis, glasshouse grown potato plants were challenged with multiple viruses and analyzed for systemic infections and symptomology studies. The results obtained conclude that multiple viral infections dramatically increase disease epidemics as compared to single infection and an effective resistance strategy in targeting multiple RNA viruses is required to save potato crop.

• 한국미생물·생명공학회지
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• 제47권2호
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• pp.317-322
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• 2019

Gastroenteritis with diarrhea is one of the most infectious diseases in the world following respiratory infections. Notably, diarrhea-causing viruses (DVs) cause more than 70% of such cases. In this study, 3,065 stool specimens from patients with diarrhea (median age, 1.1 years; range, 0.0-91.1 years), who were admitted to the DanKook University Hospital, were examined using multiplex reverse transcription PCR (mRT-PCR). The target viruses were astrovirus (AstV), enteric adenovirus (EAdV), group A rotavirus (RotV), norovirus GI (NoV-GI), and norovirus GII (NoV-GII). The mRT-PCR results were analyzed based on various factors such as seasonality, age, presence of co-infection, and analyzed trends. The detection rate of the DVs during the study period was found to be 30.8% (n = 943/3,065). When the detection rate was analyzed monthly, the DV detection rate was found to be highest between December to January. Of the detected DVs, NoV-GII was the most common, accounting for 45.5% of the detected viruses (n = 446/980). Notably, 86.5% (n = 848/980) of the pathogens were detected in individuals who were less than 5 years of age. During the study period, NoV-GII and RotV showed alternating trends. In addition, both the number and rate of co-infections increased.

• BMB Reports
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• 제52권8호
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• pp.490-495
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• 2019

Using tunneling nanotubes (TNTs), various pathological molecules and viruses disseminate to adjacent cells intercellularly. Here, we show that the intracellular invasion of Mycoplasma hyorhinis induces the formation of actin- and tubulin-based TNTs in various mammalian cell lines. M. hyorhinis was found in TNTs generated by M. hyorhinis infection in NIH3T3 cells. Because mycoplasma-free recipient cells received mycoplasmas from M. hyorhinis-infected donor cells in a mixed co-culture system and not a spatially separated co-culture system, direct cell-to-cell contact via TNTs was necessary for the intracellular dissemination of M. hyorhinis. The activity of Rac1, which is a small GTP binding protein, was increased by the intracellular invasion of M. hyorhinis, and its pharmacological and genetic inhibition prevented M. hyorhinis infection-induced TNT generation in NIH3T3 cells. The pharmacological and genetic inhibition of Rac1 also reduced the cell-to-cell dissemination of M. hyorhinis. Based on these data, we conclude that intracellular invasion of M. hyorhinis induces the formation of TNTs, which are used for the cell-to-cell dissemination of M. hyorhinis.

• Journal of Medicine and Life Science
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• 제20권3호
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• pp.107-114
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• 2023

Epidemiological control of coronavirus disease 2019 (COVID-19) is needed to estimate the infection period of confirmed cases and identify potential cases. The present study, targeting confirmed cases for which the time of COVID-19 symptom onset was disclosed, aimed to investigate the relationship between intervals (day) from symptom onset to testing the cycle threshold (CT) values of real-time reverse transcription-polymerase chain reaction. Of the COVID-19 confirmed cases, those for which the date of suspected symptom onset in the epidemiological investigation was specifically disclosed were included in this study. Interval was defined as the number of days from symptom onset (as disclosed by the patient) to specimen collection for testing. A locally weighted regression smoothing (LOWESS) curve was applied, with intervals as explanatory variables and CT values (CTR for RdRp gene and CTE for E gene) as outcome variables. After finding its non-linear relationship, a polynomial regression model was applied to estimate the 95% confidence interval values of CTR and CTE by interval. The application of LOWESS in 331 patients identified a U-shaped curve relationship between the CTR and CTE values according to the number of interval days, and both CTR and CTE satisfied the quadratic model for interval days. Active application of these results to epidemiological investigations would minimize the chance of failing to identify individuals who are in contact with COVID-19 confirmed cases, thereby reducing the potential transmission of the virus to local communities.

• The Plant Pathology Journal
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• 제40권3호
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• pp.290-298
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• 2024

K-Maryblyt has been developed for the effective control of secondary fire blight infections on blossoms and the elimination of primary inoculum sources from cankers and newly emerged shoots early in the season for both apple and pear trees. This model facilitates the precise determination of the blossom infection timing and identification of primary inoculum sources, akin to Maryblyt, predicting flower infections and the appearance of symptoms on various plant parts, including cankers, blossoms, and shoots. Nevertheless, K-Maryblyt has undergone significant improvements: Integration of Phenology Models for both apple and pear trees, Adoption of observed or predicted hourly temperatures for Epiphytic Infection Potential (EIP) calculation, incorporation of adjusted equations resulting in reduced mean error with 10.08 degree-hours (DH) for apple and 9.28 DH for pear, introduction of a relative humidity variable for pear EIP calculation, and adaptation of modified degree-day calculation methods for expected symptoms. Since the transition to a model-based control policy in 2022, the system has disseminated 158,440 messages related to blossom control and symptom prediction to farmers and professional managers in its inaugural year. Furthermore, the system has been refined to include control messages that account for the mechanism of action of pesticides distributed to farmers in specific counties, considering flower opening conditions and weather suitability for spraying. Operating as a pivotal module within the Fire Blight Forecasting Information System (FBcastS), K-Maryblyt plays a crucial role in providing essential fire blight information to farmers, professional managers, and policymakers.

• IMMUNE NETWORK
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• 제21권1호
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• pp.10.1-10.13
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• 2021

The coronavirus disease 2019 (COVID-19) pandemic (severe acute respiratory syndrome coronavirus 2) is a global infectious disease with rapid spread. Some patients have severe symptoms and clinical signs caused by an excessive inflammatory response, which increases the risk of mortality. In this study, we reanalyzed scRNA-seq data of cells from bronchoalveolar lavage fluids of patients with COVID-19 with mild and severe symptoms, focusing on Ab-producing cells. In patients with severe disease, B cells seemed to be more activated and expressed more immunoglobulin genes compared with cells from patients with mild disease, and macrophages expressed higher levels of the TNF superfamily member B-cell activating factor but not of APRIL (a proliferation-inducing ligand). In addition, macrophages from patients with severe disease had increased pro-inflammatory features and pathways associated with Fc receptor-mediated signaling, compared with patients with mild disease. CCR2-positive plasma cells accumulated in patients with severe disease, probably because of increased CCL2 expression on macrophages from patients with severe disease. Together, these results support the hypothesis that different characteristics of B cells might be associated with the severity of COVID-19 infection.