• Journal of Microbiology and Biotechnology
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• v.31 no.2
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• pp.304-316
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• 2021

Vaccination is the most effective way to prevent influenza virus infections. However, conventional vaccines based on hemagglutinin (HA) have to be annually updated because the HA of influenza viruses constantly mutates. In this study, we produced a 3M2e-3HA2-NP chimeric protein as a vaccine antigen candidate using an Escherichia coli expression system. The vaccination of chimeric protein (15 ㎍) conferred complete protection against A/Puerto Rico/8/1934 (H1N1; PR8) in mice. It strongly induced influenza virus-specific antibody responses, cytotoxic T lymphocyte activity, and antibody-dependent cellular cytotoxicity. To spare the dose and enhance the cross-reactivity of the chimeric, we used a complex of poly-γ-glutamic acid and alum (PGA/alum) as an adjuvant. PGA/alum-adjuvanted, low-dose chimeric protein (1 or 5 ㎍) exhibited higher cross-protective effects against influenza A viruses (PR8, CA04, and H3N2) compared with those of chimeric alone or alum-adjuvanted proteins in vaccinated mice. Moreover, the depletion of CD4+ T, CD8+ T, and NK cells reduced the survival rate and efficacy of the PGA/alum-adjuvanted chimeric protein. Collectively, the vaccination of PGA/alum-adjuvanted chimeric protein induced strong protection efficacy against homologous and heterologous influenza viruses in mice, which suggests that it may be a promising universal influenza vaccine candidate.

• BMB Reports
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• v.47 no.4
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• pp.215-220
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• 2014

Molecular-targeted therapy has gained attention because of its high efficacy and weak side effects. Previously, we confirmed that transmembrane 4 superfamily member 5 protein (TM4SF5) can serve as a molecular target to prevent or treat hepatocellular carcinoma (HCC). We recently extended the application of the peptide vaccine, composed of CpG-DNA, liposome complex, and TM4SF5 peptide, to prevent colon cancer in a mouse model. Here, we first implanted mice with mouse colon cancer cells and then checked therapeutic effects of the vaccine against tumor growth. Immunization with the peptide vaccine resulted in robust production of TM4SF5-specific antibodies, alleviated tumor growth, and reduced survival rate of the tumor-bearing mice. We also found that serum levels of VEGF were markedly reduced in the mice immunized with the peptide vaccine. Therefore, we suggest that the TM4SF5-specific peptide vaccine has a therapeutic effect against colon cancer in a mouse model.

• KSBB Journal
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• v.26 no.2
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• pp.107-111
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• 2011

The essential operating parameters in virus vaccine production are multiplicity of infection (MOI), harvest time, and infection time. Stimulating agents also can be applied in order to improve vaccine productivity further. We investigated the optimum operating conditions in porcine transmissible gastroenteritis virus (TGEV) vaccine production and the applicability of sodium butyrate (NaBu) as a stimulating agents for the improvement of vaccine productivity. The optimum MOI, infection time, and harvest time for high production of TGEV by swine testicle (ST) cells were found to be 0.0001 pfu/cell, 3 day after cell inoculation, and 24 hpi, respectively. NaBu is known as a histone deacetylase inhibitor that has been widely used for the high expression of recombinant protein using mammalian cells and for the enhancement of virus propagation. So we tried to examine the potential of NaBu as a stimulating agent and to determine the optimum concentration by comparing TGEV titers with different range of NaBu concentration. TGEV titer with 5 mM NaBu was 1.5 times higher than control. Therefore, we concluded that NaBu can be a promising agent for stimulating various vaccine production including TGEV and the optimum NaBu concentration for TGEV production was determined to be 5 mM.

• Clinical and Experimental Vaccine Research
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• v.12 no.3
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• pp.232-239
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• 2023

Purpose: The purpose of this study was to compare the antigenic potency and stability of tetanus and diphtheria (Td) vaccines when combined with aluminum phosphate (AlPO₄) and liposome adjuvants. Materials and Methods: In vitro and in vivo analyses were conducted using the single radial immunodiffusion method and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The Td vaccines were prepared with AlPO₄ adsorption and liposome-mediated delivery, and protein antigens were characterized using these methods. Results: The results revealed that the liposome-mediated Td vaccines exhibited higher immunogenicity compared to the AlPO₄-adsorbed Td vaccines. Additionally, the liposome-mediated Td vaccines demonstrated higher stability as native antigens. Conclusion: This study highlights the importance of utilizing liposome adjuvants in vaccine development. The liposome-mediated Td vaccines showed enhanced immunogenicity and stability, making them a promising approach for improving vaccine efficacy. Understanding and optimizing adjuvant strategies can contribute to the development of effective vaccines against various diseases.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.3
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• pp.215-222
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• 2006

The Lowry method was used in this study to measure protein in Haemophilus influenzae type b (Hib) conjugate vaccines (polyribosylibitol phosphate-tetanus toxoid; PRP-TT) using deoxycholic acid (DOC) to induce protein precipitation. Trichloroacetic acid (TCA) did not induce precipitation adequately from the Hib conjugate bulk and the freeze-dried Hib conjugate product. Its yield was approximately 50%. The matrix structure of Hib conjugate inhibits precipitation by TCA. Although the Lowry method can be carried out without precipitation in Hib conjugate bulk when no residual impurities (adipic acid dihydrazide [ADH], 1-ethyl-3-(3-dimethylamino-propyl) carbodiimide-HCI [EDAC], phenol and cyanogens bromide [CNBr], etc.) are present, it cannot be used for Hib conjugate products that contain sucrose 8.5%, because 8.5% concentration of sucrose enhanced the protein concentration. DOC- and HCl-induced precipitation is an alternative method for evaluating the protein content of the Hib conjugate bulk and the Hib conjugate product. The precipitation was optimal with a final concentrate of 0.1% for DOC at $4^{\circ}C$ and pH 2. This Lowry method, using DOC/HCI precipitation to induce protein precipitation, was confirmed a consistent, reproducible, and valid test for proteins in Hib conjugate bulk and its freeze-dried product.

• Journal of Animal Science and Technology
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• v.65 no.4
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• pp.698-719
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• 2023

Postweaning multisystemic wasting syndrome (PMWS) is caused by a systemic inflammation after porcine circovirus type 2 (PCV2) infection. It was one of the most economically important pathogens affecting pig production worldwide before PCV2 vaccine was first introduced in 2006. After the development of a vaccine against PCV2a type, pig farms gradually restored enormous economic losses from PMWS. However, vaccine against PCV2a type could not be fully effective against several different PCV2 genotypes (PCV2b - PCV2h). In addition, PCV2a vaccine itself could generate antigenic drift of PCV2 capsid. Therefore, PCV2 infection still threats pig industry worldwide. PCV2 infection was initially found in local tissues including reproductive, respiratory, and digestive tracks. However, PCV2 infection often leads to a systemic inflammation which can cause severe immunosuppression by depleting peripheral lymphocytes in secondary lymphoid tissues. Subsequently, a secondary infection with other microorganisms can cause PMWS. Eleven putative open reading frames (ORFs) have been predicted to encode PCV2 genome. Among them, gene products of six ORFs from ORF1 to ORF6 have been identified and characterized to estimate its functional role during PCV2 infection. Acquiring knowledge about the specific interaction between each PCV2 ORF protein and host protein might be a key to develop preventive or therapeutic tools to control PCV2 infection. In this article, we reviewed current understanding of how each ORF of PCV2 manipulates host cell signaling related to immune suppression caused by PCV2.

• IMMUNE NETWORK
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• v.23 no.4
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• pp.33.1-33.13
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• 2023

Vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been acknowledged as an effective mean of preventing infection and hospitalization. However, the emergence of highly transmissible SARS-CoV-2 variants of concern (VOCs) has led to substantial increase in infections among children and adolescents. Vaccine-induced immunity and longevity have not been well defined in this population. Therefore, we aimed to analyze humoral and cellular immune responses against ancestral and SARS-CoV-2 variants after two shots of the BNT162b2 vaccine in healthy adolescents. Although vaccination induced a robust increase of spike-specific binding Abs and neutralizing Abs against the ancestral and SARS-CoV-2 variants, the neutralizing activity against the Omicron variant was significantly low. On the contrary, vaccine-induced memory CD4⁺ T cells exhibited substantial responses against both ancestral and Omicron spike proteins. Notably, CD4⁺ T cell responses against both ancestral and Omicron strains were preserved at 3 months after two shots of the BNT162b2 vaccine without waning. Polyfunctionality of vaccine-induced memory T cells was also preserved in response to Omicron spike protein. The present findings characterize the protective immunity of vaccination for adolescents in the era of continuous emergence of variants/subvariants.

• Journal of Microbiology and Biotechnology
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• v.19 no.1
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• pp.108-112
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• 2009

A simplified method for the purification of cholera toxin was developed. The 569B strain of Vibrio cholerae, a recognized hyper-producer of cholera toxin, was propagated in a bioreactor under conditions that promote the production of the toxin. The toxin was separated from the bacterial cells using 0.2-${\mu}m$ crossflow microfiltration, the clarified toxin was passed through the membrane into the permeate, and the bacterial cells were retained in the retentate. The 0.2-${\mu}m$ permeate was then concentrated 3-fold and diafiltered against 10 mM phosphate buffer, pH 7.6, using 30-kDa crossflow ultrafiltration. The concentrated toxin was loaded onto a cation exchange column, the toxin was bound to the column, and most of the impurities were passed unimpeded through the column. The toxin was eluted with a salt gradient of phosphate buffer, pH 7.0, containing 1.0 M NaCl. The peak containing the toxin was assayed for cholera toxin and protein and the purity was determined to be 92%. The toxin peak had a low endotoxin level of $3.1\;EU/{\mu}g$ of toxin. The purified toxin was used to prepare antiserum against whole toxin, which was used in a $G_{M1}$ ganglioside-binding ELISA to determine residual levels of toxin in an oral inactivated whole-cell cholera vaccine. The $G_{M1}$ ganglioside-binding ELISA was shown to be very sensitive and capable of detecting as little as 1 ng/ml of cholera toxin.

• Journal of Life Science
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• v.11 no.4
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• pp.385-391
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• 2001

Filamentous hemagglutinin (FHA) is considered as an essential immunogenic component for incorporation into acellular vaccines against Bordetella pertussis, the causative agent of whooping cough. Classically, antipertussis vaccination has employed an intramuscular route. An alternative approach to stimulate mucosal and systemic immune responses is oral immunization with recombinant live vaccine carrier strains of Salmonella typhimurium. An attenuated live Salmonella vaccine sgrain($\Delta$cya $\Delta$crp) expressing recombinant FHA(rFHA) was developed. Stable expressionof rFHA was achieved by the use of balanced-lethal vector-host system. which employs an asd deletion in the host chromosome to impose in obligate requirement for diaminopimelic acid. The chromosomal $\Delta$asd mutation was complemented by a plasmid vector possessing the asd$^{+}$ gene. A 3 kb DNA fragment encoding immuno dominant regionof FHA was subcloned in-frame downstream to the ATG translation initiation codon in the multicopy Asd$^{+}$ pYA3341 vector to create pYA3457. Salmonella vaccine harboring pYA3457 expressed approximately 105kDa rFHA protein. The 100% maintenance of [YA3457 in vaccine strain was confirmed by stability examinations. Additionally, a recombinant plasmid pYA3458 was constructed to overpress His(8X)-tagged rFHA in Essherichia coli. His-tagged rFHA was purified from the E. coli strain harboring pYA3458 using Ni$^{2+}$-NTA affinity purification system.>$^{2+}$-NTA affinity purification system.

• Clinical and Experimental Pediatrics
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• v.57 no.2
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• pp.55-66
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• 2014

The 7-valent pneumococcal protein conjugate vaccine (PCV7) has been shown to be highly efficacious against invasive pneumococcal diseases and effective against pneumonia and in reducing otitis media. The introduction of PCV7 has resulted in major changes in the epidemiology of pneumococcal diseases. However, pneumococcal vaccines induce serotype-specific immunity, and a relative increase in non-vaccine serotypes has been reported following the widespread use of PCV7, leading to a need for extended serotype coverage for protection. PCV10 and PCV13 have been licensed on the basis of noninferiority of immunogenicity compared to a licensed conjugate vaccine. In this article, we aimed to review important data regarding the efficacy and effectiveness of the extended-coverage PCVs published or reported thus far and to discuss future implications for pneumococcal vaccines in Korea. After the introduction of PCV10 and PCV13, within a short period of time, evidence of protection conferred by these vaccines against invasive and mucosal infections caused by most of the serotypes included in the vaccines is accumulating. The choice of vaccine should be based on the changes in the dynamics of pneumococcal serotype distribution and diseases in the region where the vaccines are to be used. Continuous surveillance is essential for the appropriate use of pneumococcal vaccines and evaluation of the impact of PCVs on pneumococcal diseases.