• IMMUNE NETWORK
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• v.3 no.2
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• pp.110-117
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• 2003

Background: The usefulness of DNA vaccine at priming step of heterologous prime-boost vaccination led to DNA vaccine closer to practical reality. DNA vaccine priming followed by recombinant viral vector boosting via systemic route induces optimal systemic immunity but no mucosal immunity. Mucosal vaccination of the reversed protocol (recombinant viral vector priming-DNA vaccine boosting), however, can induce both maximal mucosal and systemic immunity. Here, we tried to address the reason why the mucosal protocol of prime-boost vaccination differs from that of systemic vaccination. Methods: To address the importance of primary immunity induced at priming step, mice were primed with different doses of DNA vaccine or coadministration of DNA vaccine plus mucosal adjuvant, and immunity including serum IgG and mucosal IgA was then determined following boosting with recombinant viral vector. Next, to assess influence of humoral pre-existing immunity on boosting $CD8^+$ T cell-mediated immunity, $CD8^+$ T cell-mediated immunity in B cell-deficient (${\mu}K/O$) mice immunized with prime-boost regimens was evaluated by CTL assay and $IFN-{\gamma}$-producing cells. Results: Immunity primed with recombinant viral vector was effectively boosted with DNA vaccine even 60 days later. In particular, animals primed by increasing doses of DNA vaccine or incorporating an adjuvant at priming step and boosted by recombinant viral vector elicited comparable responses to recombinant viral vector primed-DNA vaccine boosted group. Humoral pre-existing immunity was also unlikely to interfere the boosting effect of $CD8^+$ T cell-mediated immunity by recombinant viral vector. Conclusion: This report provides the important point that optimally primed responses should be considered in mucosal immunization of heterologous prime-boost regimens for inducing the effective boosting at both mucosal and systemic sites.

• BMB Reports
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• v.31 no.5
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• pp.432-443
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• 1998

The poliovirus Sabin 1 strain has features that make it a particularly attractive live recombinant mucosal vaccine vehicle. Sabin 1 cDNA was manipulated to have multiple cloning sites and a viral specific 3C-protease cutting site at the N-terminal end of the polyprotein. The gene for the N-terminal 169 amino acids of the HIV-1 p24 was cloned into the multiple cloning site of the manipulated Sabin cDNA. A recombinant progeny virus was produced from HeLa cells when it was transfected with the RNA synthesized from the p24-Sabin chimeric cDNA. The recombinant progeny virus expresses substantial amounts of the HIV-1 p24 protein, which was clearly detected in the infected cell lysates and culture supernatants in Western blot experiments with rabbit anti-p24 serum and AIDS patients' sera. Differing from the Mahoney strain, the recombinant Sabin 1 poliovirus maintained the foreign gene stably during the subsequent passages. Replication capacity was about 1 to 1.5 log lower than that of the wild-type Sabin 1. Other physicochemical stability characteristics of the recombinant virus were similar to that of the wild-type Sabin 1. These results suggest that the manipulated Sabin 1 poliovirus can be used as a live viral vaccine vector for the development of mucosal vaccines.

• Proceedings of the Microbiological Society of Korea Conference
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• 1999.04a
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• pp.46.1-46.1
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• 1999

• 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.

• IMMUNE NETWORK
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• v.13 no.6
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• pp.275-282
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• 2013

Influenza virus is one of the major sources of respiratory tract infection. Due to antigenic drift in surface glycoproteins the virus causes annual epidemics with severe morbidity and mortality. Although hemagglutinin (HA) is one of the highly variable surface glycoproteins of the influenza virus, it remains the most attractive target for vaccine development against seasonal influenza infection because antibodies generated against HA provide virus neutralization and subsequent protection against the virus infection. Combination of recombinant adenovirus (rAd) vector-based vaccine and mucosal administration is a promising regimen for safe and effective vaccination against influenza. In this study, we constructed rAd encoding the globular head region of HA from A/Puerto Rico/8/34 virus as vaccine candidate. The rAd vaccine was engineered to express high level of the protein in secreted form. Intranasal or sublingual immunization of mice with the rAd-based vaccine candidates induced significant levels of sustained HA-specific mucosal IgA and IgG. When challenged with lethal dose of homologous virus, the vaccinated mice were completely protected from the infection. The results demonstrate that intranasal or sublingual vaccination with HA-encoding rAd elicits protective immunity against infection with homologous influenza virus. This finding underlines the potential of our recombinant adenovirus-based influenza vaccine candidate for both efficacy and rapid production.

• Journal of Plant Biotechnology
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• v.31 no.2
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• pp.151-161
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• 2004

Transgenic plants have been studied as delivery system for edible vaccine against various diseases. Edible plant vaccines have several potential advantages as follows: an inexpensive source of antigen, easy administration, reduced need for medical personnel, economical to mass produce and easy transport, heat-stable vaccine without refrigerator, generation of systemic and mucosal immunity and safe antigen without fetal animal-virus contaminants. The amount of recombinant antigens in transgenic plants ranged from 0.002 to 0.8％ in total soluble protein, depending on promoters for the expression of interested genes and plants to be used for transformation. Throughout the last decade, edible plant vaccine made notable progresses that protect from challenges against virus or bacteria. However edible plant vaccines have still problems that could be solved. First, the strong promoter or inducible promoter or strategy of protein targeting could be solved to improve the low expression of antigens in transgenic plants. Second, the transformation technique of target plant should be developed to be able to eat uncooked. Third, marker-free vector could be constructed to be more safety. In this review we describe advances of edible plant vaccines, focusing on the yields depending on plants/promoters employed and the results of animal/clinical trials, and consider further research for the development of a new plant-derived vaccine.

• IMMUNE NETWORK
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• v.12 no.1
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• pp.8-17
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• 2012

Background: Respiratory syncytial virus (RSV) is a major cause of severe lower respiratory tract diseases in infancy and early childhood. Despite its importance as a pathogen, there is no licensed vaccine against RSV yet. The attachment glycoprotein (G) of RSV is a potentially important target for protective antiviral immune responses. Recombinant baculovirus has been recently emerged as a new vaccine vector, since it has intrinsic immunostimulatory properties and good bio-safety profile. Methods: We have constructed a recombinant baculovirus-based RSV vaccine, Bac-RSV/G, displaying G glycoprotein, and evaluated immunogenicity and protective efficacy by intranasal immunization of BALB/c mice with Bac-RSV/G. Results: Bac-RSV/G efficiently provides protective immunity against RSV challenge. Strong serum IgG and mucosal IgA responses were induced by intranasal immunization with Bac-RSV/G. In addition to humoral immunity, G-specific Th17- as well as Th1-type T-cell responses were detected in the lungs of Bac-RSV/G-immune mice upon RSV challenge. Neither lung eosinophilia nor vaccine-induced weight loss was observed upon Bac-RSV/G immunization and subsequent RSV infection. Conclusion: Our data demonstrate that intranasal administration of baculovirus-based Bac-RSV/G vaccine is efficient for the induction of protection against RSV and represents a promising prophylactic vaccination regimen.

• BMB Reports
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• v.38 no.6
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• pp.717-724
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• 2005

The nontoxic B subunit of cholera toxin (CTB) can significantly increase the ability of proteins to induce immunological tolerance after oral administration, when it was conjugated to various proteins. Recombinant CTB offers great potential for treatment of autoimmune disease. Here we firstly investigated the feasibility of silkworm baculovirus expression vector system for the cost-effective production of CTB under the control of a strong polyhedrin promoter. Higher expression was achieved via introducing the partial non-coding and coding sequences (ATAAAT and ATGCCGAAT) of polyhedrin to the 5' end of the native CTB gene, with the maximal accumulation being approximately 54.4 mg/L of hemolymph. The silkworm bioreactor produced this protein vaccine as the glycoslated pentameric form, which retained the GM1-ganglioside binding affinity and the native antigenicity of CTB. Further studies revealed that mixing with silkworm-derived CTB increases the tolerogenic potential of insulin. In the nonconjugated form, an insulin : CTB ratio of 100 : 1 was optimal for the prominent reduction in pancreatic islet inflammation. The data presented here demonstrate that the silkworm bioreactor is an ideal production and delivery system for an oral protein vaccine designed to develop immunological tolerance against autoimmune diabetes and CTB functions as an effective mucosal adjuvant for oral tolerance induction.

• Proceedings of the Microbiological Society of Korea Conference
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• 2002.10a
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• pp.121-124
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• 2002

This work was initiated to develope a recombinant oral poliovaccine (OPV), which is highly advanced in safety (minimizing VAPP) by introducing Type 2,3 poliovirus epitopes into our RPS-Vax system. We have introduced several potential vaccine epitopes of poliovirus Type 2, and 3 into RPS-Vax system, resulting in production of recombinant polioviruses. Any of these chimeric viruses, however, were not detected for their foreign gene expression by serotype-specific mouse antiserum. We have designed several folding units to stabilize the introduced vaccine protein and attached short epitope-concatamer or epitope-multimer to them, followed by production of chimeric viruses. Only those who have an HIV-1 Tat-mediated folding unit were nicely detected for the introduced foreign proteins by anti-Tat antiserum and type-specific peptide-induced antisera. Nevertheless, introduced epitopes were not detected in Western blot experiment with each serotype-specific antiserum. None of the mice inoculated with these chimeric viruses showed preventative immunity when challenged with Lansing and Leon wildtype 2 and 3 poliovirus, and the antiserum did not show neutralizing capacity in vitro. Conformational epitope covering B/C loop region of type 2 and 3 were newly designed by computer modeling, and introduced into the RPS-Vax vector system, followed by production of chimeric viruses. Introduced epitope regions were nicely detected by anti-Tag23 mAb or peptide antibody, but still not detected by poliovirus antiserum. Nevertheless, neutralizing antibody was detected in the Tg-PVR mice even when inoculated once with these chimeric viruses. Also, the immunized mice showed perfect preventative immunity against the wild Type poliovirus Lancing or Leon. When boosted appropriately, those chimeric virus-inoculated Tg-PVR mice produced equivalent amounts of neutralizing antibody to those in Sabin 2/3-immunized mice. These data strongly suggest that our recombinant poliovirus (RPS-PV2 and RPS-PV3) can be used as a safe and effective rec-OPV instead of any preexisting poliovaccine.

• Journal of Veterinary Science
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• v.25 no.1
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• pp.4.1-4.14
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• 2024

Background: Lawsonia intracellularis is the causative agent of proliferative enteropathy and is associated with several outbreaks, causing substantial economic loss to the porcine industry. Objectives: In this study, we focused on demonstrating the protective effect in the mouse model through the immunological bases of two vaccine strains against porcine proliferative enteritis. Methods: We used live-attenuated Salmonella Typhimurium (ST) secreting two selected immunogenic LI antigens (Lawsonia autotransporter A epitopes and flagellin [FliC]-peptidoglycan-associated lipoprotein-FliC) as the vaccine carrier. The constructs were cloned into a Salmonella expression vector (pJHL65) and transformed into the ST strain (JOL912). The expression of immunogenic proteins within Salmonella was evaluated via immunoblotting. Results: Immunizing BALB/c mice orally and subcutaneously induced high levels of LI-specific systemic immunoglobulin G and mucosal secretory immunoglobulin A. In immunized mice, there was significant upregulation of interferon-γ and interleukin-4 cytokine mRNA and an increase in the subpopulations of cluster of differentiation (CD) 4⁺ and CD 8⁺ T lymphocytes upon splenocytes re-stimulation with LI antigens. We observed significant protection in C57BL/6 mice against challenge with 10^6.9 times the median tissue culture infectious dose of LI or 2 × 10⁹ colony-forming units of the virulent ST strain. Immunizing mice with either individual vaccine strains or co-mixture inhibited bacterial proliferation, with a marked reduction in the percentage of mice shedding Lawsonia in their feces. Conclusions: Salmonella-mediated LI gene delivery induces robust humoral and cellular immune reactions, leading to significant protection against LI and salmonellosis.