• Parasites, Hosts and Diseases
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• v.47 no.4
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• pp.409-412
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• 2009

In this experiment, the correlation between antigenemia and specific antibody responses in Toxoplasma gondii-infected rabbits was assessed. We injected 1,000 T. gondii tachyzoites (RH) subcutaneously into 5 rabbits. Parasitemia, circulating antigens, and IgM and IgG antibody titers in blood were tested by ELISA and immunoblot. For detection of parasitemia, mice were injected with blood from rabbits infected with T. gondii and mice died between days 2 and 10 post-infection (PI). Circulating antigens were detected early on day 2 PI, and the titers increased from day 4 PI and peaked on day 12 PI. Anti-Toxoplasma IgM antibody titers increased on day 6 PI and peaked on days 14-16 PI. IgG was detected from day 10 PI, and the titers increased continuously during the experiment. The antigenic protein patterns differed during the infection period, and the number of bands increased with ongoing infection by the immunoblot analysis. These result indicated that Toxoplasma circulating antigens during acute toxoplasmosis are closely related to the presence of parasites in blood. Also, the circulating antigen levels were closely correlated with IgM titers, but not with IgG titers. Therefore, co-detection of circulating antigens with IgM antibodies may improve the reliability of the diagnosis of acute toxoplasmosis.

• Journal of Society of Preventive Korean Medicine
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• v.17 no.1
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• pp.181-197
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• 2013

Objectives : This study aimed to assess the differences in treatment behavior by reviewing data of a medical institution that studies treatment behavior in URI and assessing the treatment efficacy in Korea. Methods : We analyzed the behavior of medical customers and providers of upper respiratory infection medications using the NPS published by the Health Insurance Review Assessment Service. We created an operational definition for complications, and confirmed the difference in complication distribution between medical specialties. We also performed a multivariate analysis using a mixed model to elucidate the factors influencing the occurrence of complications. Results : The outcomes of analyzing factors to influence the difference in practice patterns of the diagnosing URI between the physicians are as follows; (1) Analysis of antibiotics prescriptions rate showed significant difference from medical departments (pediatrics; 49.7%, internal medicine; 54.2%, otorhinolaryngology; 69.6%, family medicine; 61.6%, general surgery; 57.5%, p<0.001). Analysis of steroid prescriptions rate showed significant difference from medical departments (pediatrics; 3.8%, internal medicine; 4.5%, otorhinolaryngology; 5.4%, family medicine; 3.0%, general surgery; 11.2%, p<0.001). (2) In patients who visited medical institutes with the common cold, the complication distribution differed according to the medical specialty, which suggests that specific complications arise depending on the particular medical specialty (p<0.001). (3) Moreover, through multivariate analysis, we found that the complication rate is higher in clinics than in hospitals, depending on the institute's size. (p<0.001; odds ratio of 4.67 in clinics than in hospitals, 95% CI 2.66-8.21) Conclusions : We observe a deviation between the behavior of patients diagnosed with URI and medication providers. This may arise from the interaction between providers and consumers, wherein the complications are associated with the choice of outpatient department and the prevention of cutting incentives. These findings suggest that the health policies should be improved to prevent inappropriate medical practice in the treatment of pediatric URI.

• IMMUNE NETWORK
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• v.23 no.6
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• pp.43.1-43.10
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• 2023

The continuous emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) variants has provided insights for updating current coronavirus disease 2019 (COVID-19) vaccines. We examined the neutralizing activity of Abs induced by a BA.4/5-containing bivalent mRNA vaccine against Omicron subvariants BN.1 and XBB.1.5. We recruited 40 individuals who had received a monovalent COVID-19 booster dose after a primary series of COVID-19 vaccinations and will be vaccinated with a BA.4/5-containing bivalent vaccine. Sera were collected before vaccination, one month after, and three months after a bivalent booster. Neutralizing Ab (nAb) titers were measured against ancestral SARS-CoV-2 and Omicron subvariants BA.5, BN.1, and XBB.1.5. BA.4/5-containing bivalent vaccination significantly boosted nAb levels against both ancestral SARS-CoV-2 and Omicron subvariants. Participants with a history of SARS-CoV-2 infection had higher nAb titers against all examined strains than the infection-naïve group. NAb titers against BN.1 and XBB.1.5 were lower than those against the ancestral SARS-CoV-2 and BA.5 strains. These results suggest that COVID-19 vaccinations specifically targeting emerging Omicron subvariants, such as XBB.1.5, may be required to ensure better protection against SARS-CoV-2 infection, especially in high-risk groups.

• Tuberculosis and Respiratory Diseases
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• v.78 no.4
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• pp.366-370
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• 2015

Although influenza A (H1N1) virus leads to self-limiting illness, co-infection with bacteria may result in cases of severe respiratory failure due to inflammation and necrosis of intra-airway, as pseudomembranous tracheobronchitis. Pseudomembranous tracheobronchitis is usually developed in immunocompromised patients, but it can also occur in immunocompetent patients on a very rare basis. We report a case of pseudomembranous tracheobronchitis complicated by co-infection of inflenaza A and Staphylococcus aureus, causing acute respiratory failure in immunocompetent patients.

• Tuberculosis and Respiratory Diseases
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• v.76 no.2
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• pp.84-87
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• 2014

We hereby observe four co-infection cases of pandemic influenza H1N1 and Mycobacterium tuberculosis with various clinical presentations. It may be prudent to consider M. tuberculosis co-infections when patients with pandemic influenza reveal unusual clinical features that do not improve despite appropriate treatments against the influenza, especially in Korea, in the endemic areas of M. tuberculosis.

• IMMUNE NETWORK
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• v.23 no.2
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• pp.13.1-13.24
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• 2023

The coronavirus disease 2019 (COVID-19) pandemic is one of the most consequential global health crises in over a century. Since its discovery in 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to mutate into different variants and sublineages, rendering previously potent treatments and vaccines ineffective. With significant strides in clinical and pharmaceutical research, different therapeutic strategies continue to be developed. The currently available treatments can be broadly classified based on their potential targets and molecular mechanisms. Antiviral agents function by disrupting different stages of SARS-CoV-2 infection, while immune-based treatments mainly act on the human inflammatory response responsible for disease severity. In this review, we discuss some of the current treatments for COVID-19, their mode of actions, and their efficacy against variants of concern. This review highlights the need to constantly evaluate COVID-19 treatment strategies to protect high risk populations and fill in the gaps left by vaccination.

• Pediatric Infection and Vaccine
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• v.14 no.1
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• pp.69-74
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• 2007

Purpose : Human coronanviruses (hCovs) including hCoV-229E and hCoV-OC43 have been known as etiologic agents of the common colds and were regarded as clinically insignificant agents. However, recent identification of hCoV-NL63 and hCoV-HKU1 in children with lower respiratory tract infections has evoked the clinical concerns about their prevalence and the clinical significance of these hCoVs in children. This study was performed to investigate the prevalence of hCoVs in children with community-acquired pneumonia. Methods : From March 2006 to January 2007, nasopharyngeal specimens collected from children hospitalized with pneumonia, were tested for the presence of common respiratory viruses (respiratory syncytial virus, influenza A, influenza B, parainfluenza viruses, and adenovirus) using multiplex reverse transcriptase polymerase chain reaction (RT-PCR). Human metapneumovirus (hMPV) infection was excluded by nested RT-PCR using primers for the F-gene. To detect the different strains of hCoVs, nested RT-PCR assays specific for hCoVNL63, hCoV-OC43, hCoV-229E, and hCoV-HKU1 were performed. Results : Out of the 217 nasopharyngeal aspirate from children aged under 15 years, respiratory syncytial virus (RSV) was detected in 32 patients, hMPV in 18, human parainfluenza virus in 10, influenza virus A in 2, and adenovirus in 6. HCoVs were detected by RT-PCR in 8 (3.7%) of the 217 patients, hCoV-229E in 1, hCoV-NL63 in 3, and hCoVOC43 in 4 patients. HCoV-HKU1 was not detected in this study population. Conclusion : Recently identified hCoV-NL63 and hCoV-HKU1 seemed to have a little clinical significance in Korean children with severe or hospitalized community-acquired pneumonia.

• Journal of Microbiology and Biotechnology
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• v.17 no.5
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• pp.739-744
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• 2007

Insect cell lines and the control of infection for obtaining the maximum amount of polyhedrin-Cry1Ac-polyhedrin fusion protein from Bactrus in monolayer and suspension culture systems were tested. Growth rates of the Trichoplusia ni(High-Five) cell line in both culture systems were better than the other insect cell lines, Spodoptera frugiferda(Sf-9, Sf-21), Trichoplusia ni(Tn5), and Spodoptera exigua(Se301). The expression of the fusion protein in a monolayer culture showed that Se301 cells were 2.3-4.8 times more productive on a per cell basis than the other cell lines. However, in suspension culture, only High-Five cells were productive. High-Five cells infected with Bactrus at a multiplicity of infection(MOI) of 5 and a cell density of $3.0{\times}10^5$ cells per ml were more productive than the other infection condition in a suspension culture suitable for a large-scale production of baculovirus. In conclusion, for the large-scale production of Bactrus in vitro, High-Five cells showing good growth and high productivity are suitable.

• Parasites, Hosts and Diseases
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• v.57 no.5
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• pp.543-547
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• 2019

Toxoplasma gondii can infect humans worldwide, causing serious diseases in pregnant women and immunocompromised individuals. T. gondii rhoptry protein 13 (ROP13) is known as one of the key proteins involved in host cell invasion. In this study, we generated virus-like particles (VLPs) vaccine expressing T. gondii rhoptry ROP13 and investigated VLPs vaccine efficacy in mice. Mice immunized with ROP13 VLPs vaccine elicited significantly higher levels of T. gondii-specific IgG, IgG1, IgG2a, and IgA antibody responses following boost immunization and challenge infection, whereas antibody inductions were insignificant upon prime immunization. Differing immunization routes resulted in differing antibody induction, as intranasal immunization (IN) induced greater antibody responses than intramuscular immunization (IM) after boost and challenge infection. IN immunization induced significantly higher levels of IgG and IgA antibody responses from feces, antibody-secreting cells (ASCs), $CD4^+$ T, $CD8^+$ T cells and germinal center B cell responses in the spleen compared to IM immunization. Compared to IM immunization, IN immunization resulted in significantly reduced cyst counts in the brain as well as lesser body weight loss, which contributed to better protection. All of the mice immunized through either route survived, whereas all na?ve control mice perished. These results indicate that the ROP13 VLPs vaccine could be a potential vaccine candidate against T. gondii infection.

• Journal of Microbiology and Biotechnology
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• v.31 no.3
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• pp.358-367
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• 2021

The World Health Organization (WHO) has declared the coronavirus disease 2019 (COVID-19) as an international health emergency. Current diagnostic tests are based on the reverse transcription-quantitative polymerase chain reaction (RT-qPCR) method, which is the gold standard test that involves the amplification of viral RNA. However, the RT-qPCR assay has limitations in terms of sensitivity and quantification. In this study, we tested both qPCR and droplet digital PCR (ddPCR) to detect low amounts of viral RNA. The cycle threshold (CT) of the viral RNA by RT-PCR significantly varied according to the sequences of the primer and probe sets with in vitro transcript (IVT) RNA or viral RNA as templates, whereas the copy number of the viral RNA by ddPCR was effectively quantified with IVT RNA, cultured viral RNA, and RNA from clinical samples. Furthermore, the clinical samples were assayed via both methods, and the sensitivity of the ddPCR was determined to be equal to or more than that of the RT-qPCR. However, the ddPCR assay is more suitable for determining the copy number of reference materials. These findings suggest that the qPCR assay with the ddPCR defined reference materials could be used as a highly sensitive and compatible diagnostic method for viral RNA detection.