• Journal of Microbiology and Biotechnology
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• 제10권6호
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• pp.865-872
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• 2000

Helocobacter phylori is the major cause of gastritis, peptic ulcer, and a principal risk factor for gastric cancer. As the firs step towards a vaccine against H. pylori infection, Hy.pylori urease was expressed and purified as a recombinant apoenzyme (rUrease) in E. coli. In order to develop an effective immunization protocol using rUrease, the host immune responses were evaluated after the oral immunization of mice with rUrease preparations plus cholera toxin relative to various conditions, such as the physical nature of the antigen, the frequency of the booster immunization, the dose of the antigen, and the route of administration. The protective efficacy was assessed using a quantitative culture following an H. pylori SS1 challenge. It was demonstrated that rUrease, due to its particulated nature, was more superior than the UreB subunit as a vaccine antigen. The oral immunization of rUrease elicited significant systemic and secretory antibody responses, and activated predominantly Th2-type cellular responses. The bacterial colonization was significantly reduced (~100-fold) in those mice immunized with three or four weekly oran doses of rUrease plus cholera toxin (p<0.05), when compared to the non-immunized/challenged controls. The protection correlated well with the elicited secretory IgA level against rUrease, and these secretory antibody responses were highly dependent on the frequency of the booster immunization, yet unaffected by the dose of the antigen (25-200$\mu\textrm{g}$). These results demonstrate the remarkable potential of rUrease as a vaccine antigen, thereby strengthening the possibility of developing an H. pylori vaccine for humans.

• 대한수의학회지
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• 제53권4호
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• pp.199-205
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• 2013

Avian pathogenic Escherichia coli (APEC) is a causative agent for a number of extra intestinal diseases and account for significant losses to the poultry industry. Since protective immunity against APEC is largely directed to virulence antigens, we have individually expressed four different viulence antigens, papA, papG, IutA, and CS31A, using an attenuated Salmonella Typhimurium and a plasmid pBB244. Following oral immunization of mice with combination of two or four of these strains, serum IgG and mucosal IgA responses were elicited against each antigen represented in the mixture. The antigen-specific mucosal IgA responses were significantly higher in the group of mice immunized with the heat-labile Escherichia coli enterotoxin B subunit (LTB) strain than those in the group of mice immunized without the LTB strain. While, there was no significant difference between these two groups in antigen-specific serum IgG responses. The results showed that LTB could act as mucosal immune adjuvant. To assess the nature of immunity, the distribution of antigen-specific IgG isotypes was analyzed. All groups promoted Th1-type immunity as determined by the IgG2a/IgG1 ratio. Thus, our findings provided evidence that immunization with a combination of several vaccine strains is one of the strategies of developing effective vaccines against APEC.

• Journal of Microbiology and Biotechnology
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• 제24권12호
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• pp.1728-1735
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• 2014

Scrub typhus, caused by infection with Orientia tsutsugamushi, is a mite-borne zoonotic disease endemic to the Asian-Pacific region. In Korea, the incidence of this disease has increased with climate changes, and over 10,000 cases of infection were reported in 2013. Although this infection is treatable with antibiotics such as doxycycline and azithromycin, an effective prophylactic vaccine against O. tsutsugamushi would be more desirable for preventing scrub typhus in endemic areas. In this study, we investigated the 56-kDa type-specific antigen (TSA56), which is a major outer membrane protein of O. tsutsugamushi, as a vaccine candidate. Intranasal immunization of recombinant TSA56 (rec56) induced a higher level of TSA56-specific IgG than that induced by intramuscular immunization of tsa56-expressing DNA (p56). Both types of immunization induced a cell-mediated immune response to TSA56, as demonstrated by the splenic cell proliferation assay. Mice immunized with p56, followed by rec56 plus heat-labile enterotoxin B subunit from E. coli, had a stronger protection from a homologous challenge with the O. tsutsugamushi Boryong strain than with other combinations. Our preliminary results suggest that an effective human vaccine for scrub typhus can include either recombinant TSA56 protein or tsa56-expressing DNA, and provide the basis for further studies to optimize vaccine performance using additional antigens or different adjuvants.

• Journal of Microbiology and Biotechnology
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• 제22권11호
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• pp.1580-1587
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• 2012

Japanese encephalitis virus (JEV) envelope (E) protein holds great promise for use in the development of a recombinant vaccine. Purified recombinant E (rE) protein may be useful for numerous clinical applications; however, there are limitations in using the Escherichia coli expression system for producing high-quality rE protein. Therefore, in this study, the yeast expression system was used to generate the rE protein. For protein production using the yeast system, the full-length JEV E gene was cloned into Pichia pastoris. SDS-PAGE and immunoblotting analysis demonstrated that the rE protein had a molecular mass of 58 kDa and was glycosylated. The predicted size of the mature unmodified E protein is 53 kDa, suggesting that post-translational modifications resulted in the higher molecular mass. The rE protein was purified to greater than 95% purity using combined ammonium sulfate precipitation and a SP-Sepharose Fast Flow column. This purified rE protein was evaluated for immunogenicity and protective efficacy in mice. The survival rates of mice immunized with the rE protein were significantly increased over that of Hyphantria cunea nuclear polyhedrosis virus E protein (HcE). Our results indicate that the rE protein expressed in the P. pastoris expression system holds great promise for use in the development of a subunit vaccine against JEV.

• IMMUNE NETWORK
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• 제16권5호
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• pp.305-310
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• 2016

In this study, we compared two different tumor cell vaccines for their induction of anti-tumor immunity; one was a tumor cell clone expressing a membrane-bound form of IL-12 p35 subunit (mbIL-12 p35 tumor clone), and the other was a tumor clone expressing heterodimeric IL-12 as a single chain (mb-scIL-12 tumor clone). The stimulatory effect of mb-scIL-12 on the proliferation of ConA-activated splenocytes was higher than that of mbIL-12 p35 in vitro. However, the stimulatory effect of mbIL-12 p35 was equivalent to that of recombinant soluble IL-12 (3 ng/ml). Interestingly, both tumor clones (mbIL-12 p35 and mb-scIL-12) showed similar tumorigenicity and induction of systemic anti-tumor immunity in vivo, suggesting that tumor cell expression of the membrane-bound p35 subunit is sufficient to induce anti-tumor immunity in our tumor vaccine model.

• 미생물학회지
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• 제43권1호
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• pp.7-13
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• 2007

Pasteurella multocida는 돼지에서 위축성 비염, 폐렴을 비롯한 다양한 호흡기 질환을 일으키는 병원균이다. 본 연구에서는 돼지 위축성 비염에 대한 효과적인 순수정제 백신을 개발하고자 하는 기초 연구로서 P. multocida의 외막 단백질 H에 의해 유도되는 방어적 항체와 면역을 확인하였다. P. multocida의 외막 단백질을 포함하는 분획은 호흡기 질병 혼합 백신에 대한 항혈청과 불활화된 사균 세포에 대한 항혈청 모두에서 면역학적으로 검출 가능하였다. 선행 연구에서 분리한 외막 단백질 H 유전자는 재조합 발현 백터 제작에 이용되어 대장균으로부터 재조합 외막단백질 H를 정제하였다. 실험 동물 면역과 항혈청의 교차반응, ELISA를 통한 항체 역가의 측정 및 공격접종을 통하여, 재조합 외막 단백질 H는 높은항원성을 가지며, 지속적인 체액성 면역을 유도하는 것을 확인하였다. 외막 단백질 H는 순수정제 항원으로서 P. multocida에 의한 호흡기 질환에 대한 효과적인 방어를 유도할 수 있는 단위 백신 후보 단백질로 여겨진다.

• Archives of Pharmacal Research
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• 제21권5호
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• pp.521-526
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• 1998

The physicochmical properties of recombinant hepatitis B surface antigen (r-HBsAg), which was expressed in C127 mammalian cell were studied. Using roller bottle culture in DMEM supplemented with fetal bovine serum, 10-15 mg/L of r-HBsAg was produced with about 31% of purification yield. The purity of r-HBsAg by HPLC was 99.8% and electron microscopic examination showed homogeneous spherical particle with 22 nm in diameter, a morphological characteristic of HBsAg. The density of r-HBsAg by CsCI density gradient method was 1.19g/ml and the isoelectric point by Mono $P^{TM}$ HR 5/20 column was 4.6. The analysis of subunit protein pattern using SDS-PAGE followed by scanning densitometry gave 81.3% of S protein and 18.7% of pre-S protein. fluorophore-assisted-carbohydrate-electrophoresis analysis showed the relative amount of carbohydrate to protein was 1.7% and it smajr component was N-acetyl glucosamine, which was about 39% of total carbohydrate. The relative amount of lipid to protein determined by vanillin phosphoric acid method was 32.5% and its major component was phospholipid, which was about 70% of total lipid. The physicochemical properties of C127 mammalian cell-derved r-HBsAg are similar to those of p-HBsAg, suggesting that the r-HBsAg can be used in developing a new preventive vaccine against hepatitis B.

• Biomolecules & Therapeutics
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• 제20권3호
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• pp.320-325
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• 2012

Rotavirus and hepatitis A virus (HAV) spread by the fecal-oral route and infections are important in public health, especially in developing countries. Here, two antigenic epitopes of the HAV polyprotein, domain 2 (D2) and domain 3 (D3), were recombined with rotavirus VP7, generating D2/VP7 and D3/VP7, cloned in a baculovirus expression system, and expressed in Spodoptera frugiperda 9 (Sf9) insect cells. All were highly expressed, with peak expression 2 days post-infection. Western blotting and ELISA revealed that two chimeric proteins were antigenic, but only D2/VP7 was immunogenic and elicited neutralizing antibody responses against rotavirus and HAV by neutralization assay, implicating D2/VP7 as a multivalent subunit-vaccine Candidate for preventing both rotavirus and HAV infections.

• BMB Reports
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• 제33권6호
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• pp.483-492
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• 2000

The Herpes simplex virus type 1 (HSV-1) strain F glycoprotein H (gH) gene in the pHLB-4 plasmid was recombinated into a baculovirus expression vector (lacZ-HcNPV) to construct a recombinant virus GH-HcNPV expressing gH. The sequences of gH and its expression were analyzed. The gH gene was located in the 6.41 kb BglII fragment. The open reading frame (ORF) of the gH gene was 2,517 bp and codes 838 amino acid residues. Insect cells infected with this recombinant virus synthesized a high level of the matured and gX-gH fusion protein with approximately 112 kDa. The fusion gH protein was localized on the membrane of the insect cells as seen by using immunofluorescence assay and accumulated in the cultured media by the SDS-PAGE and immunoprecipitation assays. The amino acid sequence presents additional characteristics compatible with the structure of a viral glycoprotein: signal peptide, putative glycosylation sites and a long C-terminal transmembrane sequence. Antibodies raised in mice to this recombinant protein recognized viral gH and neutralized the infectivity of HSV-1 in vitro. These results demonstrate that it is possible to produce a mature protein by gene transfer in eukaryotic cells, and indicate the utility of the HcNPV-insect cell system for producing and characterizing eukaryotic proteins. Furthermore, the neutralizing antibodies would appear to protect mice against HSV; accordingly, this particular recombinant protein may be useful in the development of a subunit vaccine.

• Journal of Microbiology and Biotechnology
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• 제29권2호
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• pp.330-338
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• 2019

Chronic infection with intracellular Brucella abortus (B. abortus) in livestock remains as a major problem worldwide. Thus, the search for an ideal vaccine is still ongoing. In this study, we evaluated the protective efficacy of a combination of B. abortus recombinant proteins; superoxide dismutase (rSodC), riboflavin synthase subunit beta (rRibH), nucleoside diphosphate kinase (rNdk), 50S ribosomal protein (rL7/L12) and malate dehydrogenase (rMDH), cloned and expressed into a pMal vector system and $DH5{\alpha}$, respectively, and further purified and applied intraperitoneally into BALB/c mice. After first immunization and two boosters, mice were infected intraperitoneally (IP) with $5{\times}10^4CFU$ of virulent B. abortus 544. Spleens were harvested and bacterial loads were evaluated at two weeks post-infection. Results revealed that this combination showed significant reduction in bacterial colonization in the spleen with a log protection unit of 1.31, which is comparable to the average protection conferred by the widely used live attenuated vaccine RB51. Cytokine analysis exhibited enhancement of cell-mediated immune response as IFN-${\gamma}$ is significantly elevated while IL-10, which is considered beneficial to the pathogen's survival, was reduced compared to control group. Furthermore, both titers of IgG1 and IgG2a were significantly elevated at three and four-week time points from first immunization. In summary, our in vivo data revealed that vaccination with a combination of five different proteins conferred a heightened host response to Brucella infection through cell-mediated immunity which is desirable in the control of intracellular pathogens. Thus, this combination might be considered for further improvement as a potential candidate vaccine against Brucella infection.