• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.2
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• pp.304-310
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• 2024

Ricin is a highly toxic protein which is produced in the seeds of the castor oil plant. Ricin toxin A chain has ribosomal RNA N-glycosylase activity that irreversibly hydrolyses the N-glycosidic bond of the adenine residue at position 4324 within the 28S rRNA. In this study, we developed non-toxic recombinant ricin vaccine(R51) in E. coli expression system, and evaluated efficacy of the R51 according to adjuvants. When the R51 was administered using aluminum hydroxide as an adjuvant, the vaccine efficacy was higher than that of TLR agonists or aluminum phosphate. Because it is time-consuming to administer the vaccine three times at three-week intervals, we investigated the survival rate and antibody titer of mice according to the change of time interval of vaccination. Interestingly, there was no difference in survival rate and antibody titer when R51 was administered at 0, 1, and 3 weeks or 0, 2, and 4 weeks compared to when administered at 0, 3, and 6 weeks. Therefore, the developed R51 vaccine is promising to protect soldiers from Ricin attack.

• BMB Reports
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• v.47 no.7
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• pp.399-404
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• 2014

B7-H4 is a member of B7 family of co-inhibitory molecules and B7-H4 protein is found to be overexpressed in many human cancers and which is usually associated with poor survival. In this study, we developed a therapeutic vaccine made from a fusion protein composed of a tetanus toxoid (TT) T-helper cell epitope and human B7-H4IgV domain (TT-rhB7-H4IgV). We investigated the anti-tumor effect of the TT-rhB7-H4IgV vaccine in BALB/c mice and SP2/0 myeloma growth was significantly suppressed in mice. The TT-rhB7-H4IgV vaccine induced high-titer specific antibodies in mice. Further, the antibodies induced by TT-rhB7-H4IgV vaccine were capable of depleting SP2/0 cells through complement-dependent cytotoxicity (CDC) in vitro. On the other hand, the poor cellular immune response was irrelevant to the therapeutic efficacy. These results indicate that the recombinant TT-rhB7-H4IgV vaccine might be a useful candidate of immunotherapy for the treatment of some tumors associated with abnormal expression of B7-H4.

• Korean Journal of Veterinary Research
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• v.36 no.2
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• pp.359-369
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• 1996

An effective candidate subunit vaccine was prepared by using the immunostimulating complexs(ISCOMs) with Quil A and recombinant protein(gp50, gIII and inactive $\alpha$-ADV) Aujeszky's disease virus(ADV). The weaned pigs were twice immunized with a ADV-ISCOMs, and followed by intramuscular challenge with $1{\times}10^4$ $TCID_{50}$ ADV(strain Yangsan). The unvaccinated pigs were also challenged with same dose of ADV. At 5 days after challenge, the control pigs have developed ADV clinical signs. Whereas, the vaccinated pigs protected them from ADV-induced acute symptoms and death. Also, to identify the lymphocyte subpopulation in peripheral blood with pigs from ADV-ISCOMs vaccinated and control group, lymphocyte reacted with a panel of monoclonal antibodies which are specific to swine leukocyte surface antigens and assayed by the flow cytometry. MHC class I, CD2, CD8, N cells, CD11a, and CD45 antigen positive cells were decreased after inoculating virulent ADV Yangsan strain in control group. The data indicated that ISCOMs technique was useful in ADV subunit vaccine preparation and demonstrated the importance of gp50, gIII as a component of ADV vaccine.

• Journal of Microbiology and Biotechnology
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• v.24 no.12
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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
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• v.43 no.4
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• pp.354-360
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• 2005

Heat-labile enterotoxin B subunit (LTB) of enterotoxigenic Escherichia coli (ETEC) is both a strong mucosal adjuvant and immunogen. It is a subunit vaccine candidate to be used against ETEC-induced diarrhea. It has already been expressed in several bacterial and plant systems. In order to construct yeast expressing vector for the LTB protein, the eltB gene encoding LTB was amplified from a human origin enterotoxigenic E. coli DNA by PCR. The expression plasmid pLTB83 was constructed by inserting the eltB gene into the pYES2 shuttle vector immediately downstream of the GAL1 promoter. The recombinant vector was transformed into S. cerevisiae and was then induced by galactose. The LTB protein was detected in the total soluble protein of the yeast by SDS-PAGE analysis. Quantitative ELISA showed that the maximum amount of LTB protein expressed in the yeast was approximately $1.9\%$ of the total soluble protein. Immunoblotting analysis showed the yeast-derived LTB protein was antigenically indistinguishable from bacterial LTB protein. Since the whole-recombinant yeast has been introduced as a new vaccine formulation the expression of LTB in S. cerevisiae can offer an inexpensive yet effective strategy to protect against ETEC, especially in developing countries where it is needed most.

• Korean Journal of Microbiology
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• v.43 no.1
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• pp.7-13
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• 2007

Pasteurella multocida is one of the important animal pathogen causing widespread infections in various domestic animals. In swine, it causes severe respiratory diseases such as atrophic rhinitis and pneumonic pasteurellosis. To develop the efficient subunit vaccine against swine atrophic rhinitis, we investigated protective antibodies and humoral immunity of outer membrane protein H (OmpH) which is one of the major outer membrane proteins in P. multocida. Outer membrane fraction of P. multocida was immunologically detectable using antisera from both mice groups vaccinated by formalin-killed whole cells and by commercial vaccine. The expression vector for production of recombinant OmpH was constructed and the recombinant OmpH was expressed and purified from E. coli. Recombinant OmpH showed high antigenic and immunogenic properties in mice vaccination and ELISA with antisera.

• Tuberculosis and Respiratory Diseases
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• v.58 no.2
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• pp.142-152
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• 2005

Background : Priming and boosting vaccination strategy has been widely explored for new vaccine development against tuberculosis. As an effort to identify other vaccine candidates, this study was initiated to evaluate protective efficacy of adenylate kinase (AK), nucleoside diphosphate kinase (NdK), and heat shock protein 70 (Hsp70) of Mycobacterium tuberculosis. Method : M. tuberculosis genes encoding AK, NdK, and Hsp70 proteins were amplified by PCR and cloned into E. coli expression vector, pQE30. Recombinant AK, NdK, and Hsp70 was purified through Ni-NTA resin. To evaluate immune responses, we performed enzyme-linked immunosorbent assay (ELISA) for IgG isotype and $IFN-{\gamma}$ after mice were immunized subcutaneously with recombinant proteins delivered in dimethyl dioctadecylammonium bromide (DDA). Immunized- and control groups were challenged by aerosol with M. tuberculosis. The spleens and lungs of mice were removed aseptically and cultured for CFU of M. tuberculosis. Result : Vaccination with recombinant proteins AK, NdK, and Hsp70 delivered in DDA elicited significant level of antibody and $IFN-{\gamma}$ responses to corresponding antigens but no protective immunity comparable to that achieved with Mycobacterium bovis BCG. Conclusion : Recombinant proteins AK, NdK, and Hsp70 do not effectively control growth of M. tuberculosis in mice when immunized with DDA as an adjuvant.

• Parasites, Hosts and Diseases
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• v.55 no.3
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• pp.255-267
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• 2017

Malaria is an infectious disease affecting humans, which is transmitted by the bite of Anopheles mosquitoes harboring sporozoites of parasitic protozoans belonging to the genus Plasmodium. Despite past achievements to control the protozoan disease, malaria still remains a significant health threat up to now. In this study, we cloned and characterized the full-unit Plasmodium yoelii genes encoding merozoite surface protein 1 (MSP1), circumsporozoite protein (CSP), and Duffy-binding protein (DBP), each of which can be applied for investigations to obtain potent protective vaccines in the rodent malaria model, due to their specific expression patterns during the parasite life cycle. Recombinant fragments corresponding to the middle and C-terminal regions of PyMSP1 and PyCSP, respectively, displayed strong reactivity against P. yoelii-infected mice sera. Specific native antigens invoking strong humoral immune response during the primary and secondary infections of P. yoelii were also abundantly detected in experimental ICR mice. The low or negligible parasitemia observed in the secondary infected mice was likely to result from the neutralizing action of the protective antibodies. Identification of these antigenic proteins might provide the necessary information and means to characterize additional vaccine candidate antigens, selected solely on their ability to produce the protective antibodies.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.11a
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• pp.61-67
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• 1994

One fundamental problem in developing an AIDS vaccine is antigenic variation of HIV. Despite a substantial induced immune response in gp120-immunized monkeys and humans, high titers of V3-directed type specific neutralizing antibodies may not be sufficient to neutralize continuously emerging new isolates. Several studies analyzing anti-gp120 antibodies in HIV-infected individuals have clearly indicated that most broadly neutralizing antibodies are directed to conformation-dependent epitopes. Therefore, it seems important to evaluate the potential efficacy of candidate gp120 vaccines at inducing such antibodies, that might be potentially protective against multiple HIV strains. One concern in the development of any recombinant protein as a vaccine is its stability when mixed with an adjuvant. This could be a particularly important factor for recombinant gp120, given the conformational nature of its major, broadly neutralizing, epitopes. We hypothesized that gp120 complexed with recombinant CD4 could stabilize the conformation-dependent epitopes and effectively deliver these epitopes to the immune system. In this study, a soluble gp120-CD4 complex in Syntex Adjuvant Formulation was tested in mice to analyze the anti-gp120 antibody response. With the aim of defining the fine specificity and neutalizing activities of the immune response, 17Mabs were generated and characterized. The studies indicate that the gp120-CD4 complex elicits neutralizing anti-gp120 antibodies, most of which are directed to the conformation dependent epitopes.

• Journal of Microbiology and Biotechnology
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• v.22 no.3
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• pp.416-421
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• 2012

Current influenza vaccines elicit antibodies effective against homologous strains, but new strategies are urgently needed for protection against emerging epidemic or pandemic strains. Although influenza vaccine candidates based on the viral nucleoprotein (NP) or matrix protein do not elicit sterilizing immunity, they have the advantage of inducing immunity that may cover a larger number of viral strains. In this study, recombinant NP produced in Escherichia coli was purified and formulated in combination with the adjuvant ISCOMATRIX. This formulation increased a NP-specific immunity in mice, with a Th1 profile, and may constitute a promising low-cost influenza vaccine candidate, with ability to stimulate humoral and cellular immune responses.