• Biomedical Science Letters
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• v.28 no.4
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• pp.211-222
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• 2022

After more than two years of efforts to end the corona pandemic, a gradual recovery is starting in countries with high vaccination rates. Easing public health policies for a full-fledged post-corona era, such as lifting the mandatory use of outdoor mask and quarantine measures in entry have been considered in Korea. However, the continuous emergence of new variants of SARS-CoV-2 and limitations in vaccine efficacy still remain challenging. Fortunately, T cells and memory T cells, which are key components of adaptive immunity appear to contribute substantially in COVID-19 control. SARS-CoV-2 specific CD4⁺/CD8⁺ T cells are induced by natural infection or vaccination, and rapid induction and activation of T cells is mainly associated with viral clearance and attenuated clinical severity. In addition, T cell responses induced by recognition of a wide range of epitopes were minimally affected and conserved against the highly infectious subsets of omicron variants. Polyfunctional SARS-CoV-2 specific T cell memory including stem cell-like memory T cells were also developed in COVID-19 convalescent patients, suggesting long lasting protective T cell immunity. Thus, a robust T-cell immune response appears to serve as a reliable and long-term component of host protection in the context of reduced efficacy of humoral immunity and persistent mutations and/or immune escape.

• Pediatric Infection and Vaccine
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• v.30 no.3
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• pp.188-192
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• 2023

Acute hemorrhagic edema of infancy (AHEI) is a rare, benign, vascular condition that primarily affects infants, and is possibly associated with respiratory viral infections. A case involving a 47-day-old male infant, who was admitted with a 1-day history of fever, is presented. Initially, the patient developed an erythematous macular rash and patches on the hands and feet, along with swelling. The fever subsided after the first day of hospitalization, and the patient remained in generally good condition with normal oral intake. Timely recognition of AHEI is crucial to avoid unnecessary medical investigations or therapies, and to promptly identify any rare but potentially severe complications that may arise.

• Pediatric Infection and Vaccine
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• v.14 no.1
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• pp.47-54
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• 2007

Purpose : Viral respiratory tract infection is most common cause for admission to hospital in children. There are many cases with elevated transaminase level in patients with viral lower respiratory tract infection (LRTI). The aim of this study was to compare indexes of disease severity such as duration of assisted ventilation, length of hospital stay and Respiratory Distress Assessment Instrument (RDAI) score in children with viral LRTI with and without elevated transaminase levels and to determine the etiology related to elevated transaminase levels in this patients group. Methods : Virological analysis was done from respiratory specimens obtained from patients with LRTI admitted to Kangnam Sacred Heart Hospital from Jan. 2003 to Jun. 2005. Viral diagnosis was made by isolation of viruses employing HEp-2 cell culture from nasopharyngeal aspiration. Medical records of children were reviewed retrospectively. We compared age, sex, RDAI score, Respiratory Rate (RR) score and mean duration of hospital stay between patients with elevated transaminase levels (Patient Group) and patients with normal transaminase levels (Control Group). Results : Viruses were isolated from 181 children with LRTI. 16 cases were excluded according to criteria. 28 cases (17.0%) had elevated transaminase levels (Patient group) and 137 cases (83.0%) had normal transaminase levels (Control group). There were no significant difference in duration of fever, RR score, RDAI score, incidence of $O_2$ inhalation and duration of hospital stay between patient group and control group. We found 17 (60.7%) cases of RSV, 4 cases (14.3%) of parainfluenza, 4 cases (14.3%) of influenza B virus, 3 cases (10.7%) of adenovirus and 1 case (3.6%) of influenza A virus infection in patient group and 78 cases (56.9%) of RSV, 28 cases (20.4%) of parainfluenza virus, 13 cases (9.5%) of influenza A virus, 9 cases (6.6%) of influenza B virus, 6 cases (4.4%) of adenovirus and 3 cases (2.2%) of coxsackie virus infection in control group. Conclusion : There were 28 cases (17.0%) with elevated transaminase level among patients with virus isolated LRTI. There was no relation between elevated transaminase level and severity of disease. The viral etiologies in two groups were not significantly different. There was no significant difference of age distribution between two groups.

• Korean Journal of Veterinary Service
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• v.31 no.4
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• pp.533-546
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• 2008

The efficacy of bovine immune sera to correct the calves with failure of passive transfer(FPT) was evaluated. Immune sera were produced from 14 one-year-old Holstein cattle which were inoculated commercial combined viral vaccine, administered by the challenge of some main enteric or respiratory viruses, aseptically filtered and stored at $4^{\circ}C$ before used. After the treatment of bovine immune sera, Mean transfer factor($mg/d{\ell}$, of IgG administered/kg of body weight) was $5.46{\pm}2.74,\;11.17{\pm}1.27,\;1.40{\pm}0.21$ in K-IP, H-IP and K-IV group, respectively. The corrective effect of bovine immune sera to FPT calf without any clinical signs showed that intravenous route was more effective than intraperitoneal administration(P<0.01). FPT calves with severe signs were not effective response to the immunotherapy used and consequently died within 10 days after the treatment. Ten percentage of controls appeared the clinical signs including diarrhea. On the contrary, there were not any clinical signs in K-IP and H-IV group. There was significant increase of the neutralizing titer against bovine viral diarrhea virus and bovine coronavirus as well as of cell population including CD2, CD4, and monocyte in K-IP and H-IV group after the immunotherapy(P<0.05). Also, K-IP and H-IV group showed the successful correction to FPT within one week after the immunotherapy, but controls had kept the FPT two-four weeks even after the same treatment. Consequently, the results were suggesting that the bovine immune sera could be used the corrective tool to young calves with FPT.

• Pediatric Infection and Vaccine
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• v.17 no.1
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• pp.49-55
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• 2010

Purpose : The Purposes of this study are to identify the circulating etiologic viruses of acute lower respiratory tract infection in children and to understand the relation with clinical diagnosis. Methods : We obtained a total of 418 nasopharyngeal aspirates from children admitted for their acute lower respiratory tract infections at three tertiary hospitals in Seoul from September 2008 to March 2009. We performed multiplex RT-PCR to identify 14 etiologic viruses and analyzed their emerging patterns and clinical features. Results : Average age of patients was 16.4 months old and the ratio of male to female was 1.36. Viruses were detected in 56.2% of a total of 418 samples. Respiratory syncytial virus (35%) was the most frequently detected and followed by human rhinovirus (22%), human bocavirus, adenovirus, human metapneumovirus, parainfluenza virus, influenza virus and human coronavirus. Co-infection reached 21.9 % of positive patients. Conclusion : When we manage the patients with acute lower respiratory infectious diseases, we should remind the role of various viral pathogens, which might be circulating by seasons and by local areas.

• The Journal of Korean Society of Virology
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• v.28 no.3
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• pp.247-265
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• 1998

To determine the sequence and expression of the VP7 gene of Korean isolates (CAU-9), viral RNA was purified and used for cDNA amplification by RT-PCR. The VP7 cDNA was cloned, sequenced, and expressed using baculovirus expression system. The result showed that the sequence homologies CAU-9 compared with foreign isolated strains Wa, 417, TMC-II, 95B and SA11 were ranged from 74.0% to 95.1 % of nucleotide sequence and 35% to 43% of amino acid sequence, respectively. High homology of CAU-9 was observed in Japanease isolates 417 (nucleotide sequence homology was 95.1% and amino acid sequence homology was 43%). To express VP7 gene, the VP7 cDNA was cloned into pCR-Bac vector and inserted into the genome of baculovirus adjacent to the polyhedrin promoter by cotransfection of Spodoptera frugiperda (Sf9) insect cells with wild type baculovirus DNA. In antigenic analysis of Sf9 cells inoculated with the recombinant VP7, immunofluorescence assay revealed positive for viral antigens. In metabolic labeling of Sf9 cell lysates infected with recombinant baculoviruses, it was revealed that the protein of 34 kDa was expressed. The limited study of expressed VP7 protein inoculated with guinea pigs failed to elicit neutalizing antibody. As a results, the sequence analysis and expression of VP7 protein of rotavirus CAU-9 isolated from an infant in Korea could permit the conformation and development of virus like particles which may be useful in designing vaccine strategy.

• Pediatric Infection and Vaccine
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• v.24 no.2
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• pp.87-94
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• 2017

Purpose: The inappropriate prescription of antibiotics in children with upper respiratory tract infection (URTI) is common. This study evaluated the factors that influence antibiotics use in hospitalized children with viral URTI confirmed by reverse transcriptase-polymerase chain reaction (RTPCR) assay. Methods: The medical records of admitted patients who performed RT-PCR assay for respiratory virus pathogens from January 2013 to November 2014 were examined. The demographic and clinical features were compared between patients who were administered antibiotics at admission and those who were not. We also investigated differences between children who continued antibiotics and those who stopped antibiotics after a viral pathogen was identified. Results: In the total 393 inpatients, the median age was 23 months (interquartile range, 13 to 41.3 months). Antimicrobial agents were prescribed in 79 patients (20.1%) at admission. Patients with acute otitis media (AOM) had higher rates of antibiotics prescription than those without AOM (48.1% vs. 2.2%, P<0.001), with an adjusted odds ratio of 91.1 (95% confidence interval, 30.5 to 271.7). Level of high-sensitivity C-reactive protein and the proportion of acute rhinosinusitis were also significantly associated with antibiotics use (P<0.001). Among the 44 patients with viruses identified using the RT-PCR method during hospitalization, antibiotic use was continued in 28 patients (63.6%). AOM was statistically associated with continued antibiotic use in the patients (P=0.002). Conclusions: Although the respiratory virus responsible for URTI etiology is identified, clinicians might not discontinue antibiotics if AOM is accompanying. Therefore, careful diagnosis and management of AOM could be a strategy to reduce unjustified antibiotic prescriptions for children with URTI.

• Applied Chemistry for Engineering
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• v.33 no.1
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• pp.83-89
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• 2022

Since the pandemic of COVID-19, active investigation to develop immunity to infectious disease by delivering nucleic acids has been proceeded. Particularly, many studies have been conducted on non-viral vector as several vital side-effects which were found on nucleic acid delivery system using viral vectors. In this study, we have developed plasmid DNA (pDNA) loaded-hyaluronic acid derivative (HA) coated-polyethyleneimine (PEI) based polyplex for enhanced nucleic acid delivery efficiency. We have optimized the ratio of pDNA : PEI : HA by measuring size and protein transcription efficiency. The final product, polyplex-HA, was characterized through measuring size, zeta-potential and TEM image. Intracellular uptake and protein transcription efficiency were compared to commercially available transfection reagent, lipofectamine, through fluorescence image and flow cytometry. In conclusion, polyplex-HA presents a novel gene delivery system for efficient and stable protein transcription since it is available for delivering various genetic materials and has less immunoreactivity.

• Pediatric Infection and Vaccine
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• v.29 no.2
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• pp.70-76
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• 2022

Coronavirus disease 2019 (COVID-19) in patients with underlying diseases, is associated with high infection and mortality rates, which may result in acute respiratory distress syndrome and death. Mucopolysaccharidosis (MPS) type II is a progressive metabolic disorder that stems from cellular accumulation of the glycosaminoglycans, heparan, and dermatan sulfate. Upper and lower airway obstruction and restrictive pulmonary diseases are common complaints of patients with MPS, and respiratory infections of bacterial or viral origin could result in fatal outcomes. We report a case of COVID-19 in a 16-year-old adolescent with MPS type II, who had been treated with idursulfase since 5 years of age. Prior to infection, the patient's clinical history included developmental delays, abdominal distension, snoring, and facial dysmorphism. His primary complaints at the time of admission included rhinorrhea, cough, and sputum without fever or increased oxygen demand. His heart rate, respiratory rate, and oxygen saturation were within the normal biological reference intervals, and chest radiography revealed no signs of pneumonia. Consequently, supportive therapy and quarantine were recommended. The patient experienced an uneventful course of COVID-19 despite underlying MPS type II, which may be the result of an unfavorable host cell environment and changes in expression patterns of proteins involved in interactions with viral proteins. Moreover, elevated serum heparan sulfate in patients with MPS may compete with cell surface heparan sulfate, which is essential for successful interaction between the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein and the host cell surface, thereby protecting against intracellular penetration by SARS-CoV-2.

• IMMUNE NETWORK
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• v.21 no.5
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• pp.33.1-33.19
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• 2021

IL-1β plays critical roles in the priming and effector phases of immune responses such as the differentiation, commitment, and memory formation of T cells. In this context, several reports have suggested that the IL-1β signal is crucial for CTL-mediated immune responses to viral infections and tumors. However, little is known regarding whether IL-1β acts directly on CD8⁺ T cells and what the molecular mechanisms underlying expression of IL-1 receptors (IL-1Rs) on CD8⁺ T cells and features of IL-1R⁺ CD8⁺ T cells are. Here, we provide evidence that the expression of IL-1R type I (IL-1RI), the functional receptor of IL-1β, is preferentially induced by IL-21 on TCR-stimulated CD8⁺ T cells. Further, IL-1β enhances the effector function of CD8⁺ T cells expressing IL-21-induced IL-1RI by increasing cytokine production and release of cytotoxic granules containing granzyme B. The IL-21-IL-1RI-IL-1β axis is involved in an augmented effector function through regulation of transcription factors BATF, Blimp-1, and IRF4. Moreover, this axis confers a unique effector function to CD8⁺ T cells compared to conventional type 1 cytotoxic T cells differentiated with IL-12. Chemical inhibitor and immunoprecipitation assay demonstrated that IL-21 induces a unique pattern of STAT activation with the formation of both STAT1:STAT3 and STAT3:STAT5 heterodimers, which are critical for the induction of IL-1RI on TCR-stimulated CD8⁺ T cells. Taken together, we propose that induction of a novel subset of IL-1RI-expressing CD8⁺ T cells by IL-21 may be beneficial to the protective immune response against viral infections and is therefore important to consider for vaccine design.