• Pediatric Infection and Vaccine
• /
• v.29 no.1
• /
• pp.54-60
• /
• 2022

Salmonella meningitis is rare yet poses causes significant neurological morbidity in children. Infants, especially those under 3 months of age, and those with immunocompromised states, such as malignancy, malaria, and human immunodeficiency virus infection, are at increased risk for developing Salmonella meningitis. Herein, we describe a case of Salmonella meningitis in a previous healthy 8-year-old girl who presented with high fever, vomiting, and altered mental status. Group D Salmonella species were isolated in cerebrospinal fluid culture, and no abnormal findings were noted in brain magnetic resonance imaging. Immunoglobulin levels and lymphocyte subset counts were within the normal ranges, and no genetic mutation responsible for primary immunodeficiency disease was detected by next-generation sequencing. The patient's condition improved rapidly with third-generation cephalosporin, and no complications or sequalae developed. Nontyphoidal Salmonella can cause meningitis in immunocompetent children and can be successfully treated with early administration of antibiotics.

• Molecules and Cells
• /
• v.46 no.4
• /
• pp.209-218
• /
• 2023

In induced pluripotent stem cells (iPSCs), pluripotency is induced artificially by introducing the transcription factors Oct4, Sox2, Klf4, and c-Myc. When a transgene is introduced using a viral vector, the transgene may be integrated into the host genome and cause a mutation and cancer. No integration occurs when an episomal vector is used, but this method has a limitation in that remnants of the virus or vector remain in the cell, which limits the use of such iPSCs in therapeutic applications. Chemical reprogramming, which relies on treatment with small-molecule compounds to induce pluripotency, can overcome this problem. In this method, reprogramming is induced according to the gene expression pattern of extra-embryonic endoderm (XEN) cells, which are used as an intermediate stage in pluripotency induction. Therefore, iPSCs can be induced only from established XEN cells. We induced XEN cells using small molecules that modulate a signaling pathway and affect epigenetic modifications, and devised a culture method which can produce homogeneous XEN cells. At least 4 passages were required to establish morphologically homogeneous chemically induced XEN (CiXEN) cells, whose properties were similar to those of XEN cells, as revealed through cellular and molecular characterization. Chemically iPSCs derived from CiXEN cells showed characteristics similar to those of mouse embryonic stem cells. Our results show that the homogeneity of CiXEN cells is critical for the efficient induction of pluripotency by chemicals.

• Clinical and Experimental Vaccine Research
• /
• v.12 no.4
• /
• pp.328-336
• /
• 2023

Purpose: Human peripheral blood mononuclear cell (PBMC)-based in vitro systems can be of great value in the development and assessment of vaccines but require the right medium for optimal performance of the different cell types present. Here, we compare three commonly used media for their capacity to support innate and adaptive immune responses evoked in PBMCs by Toll-like receptor (TLR) ligands and whole inactivated virus (WIV) influenza vaccine. Materials and Methods: Human PBMCs were cultured for different periods of time in Roswell Park Memorial Institute (RPMI), Dulbecco's minimal essential medium (DMEM), or Iscove's modified DMEM (IMDM) supplemented with 10% fetal calf serum. The viability of the cells was monitored and their responses to TLR ligands and WIV were assessed. Results: With increasing days of incubation, the viability of PBMCs cultured in RPMI or IMDM was slightly higher than that of cells cultured in DMEM. Upon exposure of the PBMCs to TLR ligands and WIV, RPMI was superior to the other two media in terms of supporting the expression of genes related to innate immunity, such as the TLR adaptor protein gene MyD88 (myeloid differentiation factor 88), the interferon (IFN)-stimulated genes MxA (myxovirus resistance protein 1) and ISG56 (interferon-stimulated gene 56), and the leukocyte recruitment chemokine gene MCP1 (monocyte chemoattractant protein-1). RPMI also performed best with regard to the activation of antigen-presenting cells. As for adaptive immunity, when stimulated with WIV, PBMCs cultured in RPMI or IMDM contained higher numbers of IFNγ-producing T cells and secreted more immunoglobulin G than PBMCs cultured in DMEM. Conclusion: Taken together, among the different media assessed, RPMI was identified as the optimal medium for a human PBMC-based in vitro vaccine evaluation system.

• IMMUNE NETWORK
• /
• v.22 no.2
• /
• pp.15.1-15.16
• /
• 2022

Foreign molecules, including viruses and bacteria-derived toxins, can also induce airway inflammation. However, to the best of our knowledge, the roles of these molecules in the development of airway inflammation have not been fully elucidated. Herein, we investigated the precise role and synergistic effect of virus-mimicking double-stranded RNA (dsRNA) and staphylococcal enterotoxin B (SEB) in macrophages and epithelial cells. To identify cytokine expression profiles, both the THP-1-derived macrophages and BEAS-2B epithelial cells were stimulated with dsRNA or SEB. A total of 21 cytokines were evaluated in the culture supernatants. We observed that stimulation with dsRNA induced cytokine production in both cell types. However, cytokine production was not induced in SEB-stimulated epithelial cells, compared to the macrophages. The synergistic effect of dsRNA and SEB was evaluated observing cytokine level and intracellular phospho-signaling. Fifteen different types were detected in high-dose dsRNA-stimulated epithelial cells, and 12 distinct types were detected in macrophages; those found in macrophages lacked interferon production compared to the epithelial cells. Notably, a synergistic effect of cytokine induction by co-stimulation of dsRNA and SEB was observed mainly in epithelial cells, via activation of most intracellular phosphor-signaling. However, macrophages only showed an accumulative effect. This study showed that the type and severity of cytokine productions from the epithelium or macrophages could be affected by different intensities and a combination of dsRNA and SEB. Further studies with this approach may improve our understanding of the development and exacerbation of airway inflammation and asthma.

• Microbiology and Biotechnology Letters
• /
• v.44 no.3
• /
• pp.261-267
• /
• 2016

The present study examined the effect of the dietary administration of a halophilic bacterium Bacillus sp. Mk22 on the growth improvement of black tiger shrimp, Penaeus monodon, and reduced shrimp infection by Vibrio parahaemolyticus and white spot syndrome virus (WSSV). The shrimp were fed 45 days using three experimental diets: no addition (control), commercial probiotic, and Bacillus sp. Mk22. The shrimp treated with the halophilic bacterium Mk22 showed a significant improvement of growth (7.1 ± 0.21 g), survival (94.3 ± 0.58%), weight gain (178 ± 4.93 g), and reduced feed conversion rate (0.8 ± 0.03 g) compared with the shrimp in the other groups. The shrimp treated with Bacillus sp. Mk22 also showed a lower Vibrio count (0.02 ± 0.01 × 10² CFU/ml) in the shrimp culture water compared with the other groups. The shrimp in the three groups were challenged with either Vibrio or WSSV. For the Vibrio infection, no mortality was observed from water infection or oral feeding infection in the commercial probiotic group and Mk 22 group. For the WSSV infection, a 68% survival rate from water infection and 20% survival rate from oral feeding infection was observed on day 45 in the Mk22 group, while 100% mortalities were recorded at a much earlier time in both the control and commercial probiotic groups. The antioxidant enzyme activities, indicators of oxidative stress, such as catalase and superoxide dismutase, significantly decreased in both the Vibrio and WSSV-infected Mk22 groups compared with the other groups, indicating that Bacillus sp. Mk22 was effective in reducing oxidative stress, possibly due to the reduced infection.

• Pediatric Infection and Vaccine
• /
• v.20 no.3
• /
• pp.161-167
• /
• 2013

Purpose: This study was performed to describe the clinical manifestations of hospitalized children due to varicella-zoster virus (VZV) infection Methods: This study included 40 children who were hospitalized for varicella or herpes zoster at Seoul National University Children's Hospital, 2009-2012. Diagnosis of VZV infection was confirmed by VZV PCR or culture from vesicular fluid. Medical records were reviewed to collect clinical features and outcome, antiviral treatment, history of varicella vaccination, and underlying diseases. Results: Sixteen patients with varicella and 24 patients with herpes zoster were included. Their median age was 10.5 years (16 days-19 years). Thirty-five (87.5%) patients had underlying diseases. Among 24 patients with herpes zoster, 11 patients had previous history of varicella and 1 had herpes zoster. Twenty patients (50%) had a history of varicella vaccination, and 19 immunocompromised patients had VZV infection despite of vaccination. Most (95%) patients were treated by intravenous or oral acyclovir, and no treatment failure of intravenous acyclovir was found. The median duration of fever was 4.4 days (1-10 days), and that of antiviral treatment was 12 days (7-23 days) in immunocompromised patients. Immunocompromised patients received longer duration of antiviral treatment than imunocompetent patients (P=0.014). Eleven (27.5 %) immunocompromised patients had postherpetic neuralgia, 2 (5%) had proven co-infection by Streptococcus pyogenes and Klebsiella oxytoca, and 1 (2.5%) complicated with pneumonia. Conclusion: Immunocompromised children require longer duration of treatment and are at risk of severe complication associated with VZV infection. Early initiation of antiviral therapy and close monitoring are necessary for those in immunocompromised conditions.

• Pediatric Infection and Vaccine
• /
• v.5 no.2
• /
• pp.258-266
• /
• 1998

Purpose : Cases of adenoviral penumonia with rapidly progressive clinical course were experienced. We reviewed these patients in viewpoint of clinical manifestation and adenoviral serotypes. Methods : Culture and indirect immunofluorescence for respiratory viruses including respiratory syncytial virus, influenza virus, parainfluenza virus, adenovirus was done with nasopharyngeal aspirates from patients who admitted due to respiratory infections in Fatima Hospital, Masan from Nov. 1996 to Jul. 1997. Cultured adenovirus was serotyped by both neutralization and hemagglutination inhibition test. Medical records were reviewed for 5 patients with respiratory failure from adenovirus was isolated and serotyped. Results : The total number of examined patients was 460 patients. We isolated respiratory viruses in 143(30.9%) patients. Adenovirus was isolated from 66 out of 143(46.2%) patients. During Jan 1997 to May 1997, five patients with ages of 18 days to 11 months who were infected by adenovirus and had high fever with dyspnea and required assisted mechanical ventilation. One patients discharged against doctor's advice then died. Two of four patients had complications of disseminated intravascular coagulation; two had bronchiolitis obliterans. Two isolates were serotype 7, and one was serotype 5, and two were untyped. Conclusion : Severe pneumonia caused by serotype 7 continued to occur in 1997 following the epidemic in 1996, and severe pneumonia may also be caused by serotype 5 and other serotypes.

• Neonatal Medicine
• /
• v.15 no.1
• /
• pp.44-53
• /
• 2008

Purpose : Epidemic keratoconjunctivitis (EKC) caused by adenovirus is a highly contagious disease, which has been reported as outbreaks involving adults in the community. However, there has been no report on EKC outbreak by adenovirus in a neonatal intensive care unit (NICU) in Korea. Aims of this study were to investigate the EKC outbreak by adenovirus type 8 in NICU and to confirm an effectiveness of polymerase chain reaction (PCR) for diagnosis. Methods : Conjunctival swab or nasopharyngeal aspirate specimens were taken from all patients and tested by viral culture and PCR. Adenovirus serotype was determined by sequencing of PCR product of selected region of hexon gene using the virus isolates or specimens. Results : An outbreak of EKC occurred which was involving 12 preterm infants in the NICU of the Seoul National University Children's Hospital between July 12th and August 1st, 2005. Three hospital staffs and one family member of the neonate were also affected. Adenovirus was detected in 12/12 (100%), 6/11 (54.5%) by PCR and virus culture, respectively. Eleven PCR-positive neonates were identified as serotype 8 by sequencing. The first affected 4 babies have had routine ROP (retinopathy of prematurity) examinations one week ago. While previous outbreaks were sustained for a few months, the event in our unit was controlled without complications in 3 weeks. Conclusion : We analyzed the EKC outbreak by adenovirus type 8 in NICU. Adenovirus serotype was identified by PCR and sequencing with high sensitivity for the first time in Korea, so we suggest this method can be very useful for rapid diagnosis and infection control.

• Clinical and Experimental Pediatrics
• /
• v.52 no.9
• /
• pp.1053-1058
• /
• 2009

Cytomegalovirus (CMV) is one of the most commonly encountered viral pathogens in newborn infants and is found in 0.3-2.4% of all live births. It has been demonstrated that 40-96% of seropositive mothers shed the virus via their breast milk. Breast milk containing CMV can cause almost one-third of CMV infections occurring in infants. A case of postnatal CMV infection in an extremely premature infant (gestational age $24^{+5}$ weeks, birth weight 750 g) transmitted via breast milk is presented. For neonatal intensive care unit (NICU) management of severe thrombocytopenia, anemia, and sepsis syndrome, the infant received repeated transfusions of platelets; intravenous (IV) immunoglobulins; and gamma- irradiated, filtrated packed red cells and was fed her mother's breast milk since the second week of life. CMV infection was diagnosed with positive CMV immunoglobulin M (IgM) and positive urine CMV culture at the second month of life. Considering the negative CMV IgM and urine CMV culture at birth, postnatally-acquired CMV infection was suspected and confirmed with completely identical nucleotide sequence alignments of the infantile blood isolate and the maternal breast milk isolate. To our knowledge, this is the first case of proven postnatal CMV infection transmitted via breast milk in an extremely premature infant in Korea.

• Journal of Microbiology and Biotechnology
• /
• v.11 no.6
• /
• pp.915-921
• /
• 2001

Phytase improves the bioavailability of phytate phosphorus in plant foods to humans and animals, and reduces the phosphorus pollution of animal waste. In order to express a high level of fungal phytase in Saccharomyces cerevisiae, various expression vectors were constructed with different combinations of promoters, translation enhancers, signal peptides, and terminator. Three different promoters fused to the phytase gene (phyA) from Aspergillus niger were tested: a galactokinase (GAL1) promoter, glyceraldehyde-3-phosphate dehydrogenase (GPD) promoter, and yeast hybrid ADH2-GPD promoter consisting of alcohol dehydrogenase II (ADH2) and a GPD promoter. The signal peptides of phytase, glucose oxidase (GO), and rice amylase 1A(RAmy1A) were included. Plus, the translation enhancers of the ${\Omega}$ sequence and UTR70 from the tobacco mosaic virus (TMV) and spinach, respectively, were also tested. Among the recombinant vectors, pGphyA06 containing the GPD promoter, the ${\Omega}$ sequence, RAmy1A, and GAL7 terminator expressed the highest phytase activity in a culture filtrate, which was estimated at 20 IU/ml. An intracellular localization of the expressed phytase activity in a culture filtrate, which was estimated at 20 IU/ml. An intracellular localization of the expressed phytase was also performed by inserting an endoplasmic reticulum (ER) retention signal, KDEL sequence, into the C-terminus of the phytase within the vector pHphyA-6. It appeared that the KDEL sequence directed most of the early expression of phytase into the intracellular compartment yet more than $60\%$ of the total phytase activity was still retained within the cell even after the prolonged (>3 days) incubation of the transformant. However, the intracellular enzyme activity of the transformant without a KDEL sequence was as high as that of the extracellular one, thereby strongly suggesting that the secretion of phytase in S. cerevisiae appeared to be the rate-limiting step for the expression of a large amount of extracellular recombinant phytase, when compared with other yeasts.