• Journal of Life Science
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• v.33 no.9
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• pp.746-753
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• 2023

Viral infectious diseases have been regarded as one of the greatest threats to global public health. The recent coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a stark reminder of the threat posed by emerging viral infections. Developing and producing appropriate and efficient vaccines and therapeutics are the only options to combat this pandemic. The COVID-19 pandemic has highlighted the need for novel vaccine platforms to control and prevent emerging viral diseases. Conventional vaccine platforms, including live-attenuated vaccine and inactivated vaccines, pose limitations in the speed of vaccine development, manufacturing capacity, and broad protection for emergency use. Interestingly, vaccination with the SARS-CoV-2 vaccine candidate based on the mRNA-lipid nanoparticle (LNP) platform protected against COVID-19, confirming that the nucleoside-modified candidate is a safe and effective alternative to conventional vaccines. Moreover, the prophylactic strategies against the COVID-19 pandemic have been mRNA nucleic acid-based vaccines and nanoparticle-based platforms, which are effective against SARS-CoV-2 and its variants. Overall, the novel vaccine platform has presented advantages compared with the traditional vaccine platform in the COVID-19 pandemic. This review explores the recent advancements in vaccine technologies and platforms, focusing on mRNA vaccines, digital vaccines, and nanoparticles while considering their advantages and possible drawbacks.

• Korean Journal of Veterinary Research
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• v.46 no.3
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• pp.207-214
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• 2006

Mycoplasma gallisepticum (MG) continues to persist in many commercial layer farms in Korea,resulting in losses in egg production. Bacterins and live attenuated vaccines have been used for the prevention of losses caused by MG. One of these attenuated vaccines, MG 6/85 vaccine has been reported to be safe and efficacious in layers. However, MG 6/85 vaccine has not been evaluated for its safety and its efficacy in any commercial layer in Korea. Six-week-old specific pathogen-free (SPF) chickens were vaccinated with MG 6/85 vaccine by aerosol and were challenged with virulent MG R strain at 4 weeks after vaccination. The vaccinated group was able to resist challenge into the air sacs because the vaccinated group showed much less air sac lesion compared with the unvaccinated group. Each of two commercial layer farms was divided into vaccinated and unvaccinated groups. For each vaccinated gorup, MG 6/85 vaccine were sprayed at 17 week old on farm A and at 15 weeks old on farm B. Hen-day egg production, Hen-housed eggs, egg weight, mortality were evaluated until 50 week after vaccination.Compared with the unvaccinated group in each farm, the vaccinated group showed higher average egg production and egg weight, and higher hen-housed number. Results of this study are in agreement with other previous reports which demonstrated that MG 6/85 vaccine favorable effect on performance in commercial layers.

• Korean Journal of Veterinary Research
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• v.53 no.4
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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.

• Parasites, Hosts and Diseases
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• v.60 no.6
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• pp.379-391
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• 2022

Leishmaniasis is a serious parasitic disease caused by Leishmania spp. transmitted through sandfly bites. This disease is a major public health concern worldwide. It can occur in 3 different clinical forms: cutaneous, mucocutaneous, and visceral leishmaniasis (CL, MCL, and VL, respectively), caused by different Leishmania spp. Currently, licensed vaccines are unavailable for the treatment of human leishmaniasis. The treatment and prevention of this disease rely mainly on chemotherapeutics, which are highly toxic and have an increasing resistance problem. The development of a safe, effective, and affordable vaccine for all forms of vector-borne disease is urgently needed to block transmission of the parasite between the host and vector. Immunological mechanisms in the pathogenesis of leishmaniasis are complex. IL-12-driven Th1-type immune response plays a crucial role in host protection. The essential purpose of vaccination is to establish a protective immune response. To date, numerous vaccine studies have been conducted using live/attenuated/killed parasites, fractionated parasites, subunits, recombinant or DNA technology, delivery systems, and chimeric peptides. Most of these studies were limited to animals. In addition, standardization has not been achieved in these studies due to the differences in the virulence dynamics of the Leishmania spp. and the feasibility of the adjuvants. More studies are needed to develop a safe and effective vaccine, which is the most promising approach against Leishmania infection.

• Journal of Veterinary Science
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• v.24 no.5
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• pp.54.1-54.13
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• 2023

Background: Porcine reproductive and respiratory syndrome virus (PRRSV) vaccines do not provide full cross-protection, mainly due to the virus genetic variability. Despite this, vaccines based on modified-live PRRSV (PRRSV-MLV) reduce the disease impact. Objectives: To assess the efficacy of two commercial vaccines-one based on PRRSV1 (PRRSV1-MLV) and another on PRRSV2 (PRRSV2-MLV)-against a Japanese PRRSV2 field strain. Methods: Two groups of three-week-old piglets were vaccinated (G1: PRRSV1-MLV; G2: PRRSV2-MLV) and two were kept as non-vaccinated (INF and CTRL). One month later, G1, G2, and INF were challenged with a PRRSV2 field strain. Results: After the challenge, clinical signs were only observed in INF. Moreover, the highest rectal temperatures and values for the area under the curve (AUC) were observed in INF. Regarding viral detection, both AUC and the proportion of positive samples in blood were higher in INF. In G1, viremic animals never reached 100%. At necropsy (21 d after the challenge), differences for titers among groups were only found in tonsils (G1 < G2 and INF). One animal (belonging to G1) was negative in all tissues. Regarding humoral responses, G1 and G2 seroconverted after vaccination, as detected in the corresponding enzyme-linked immunosorbent assay. Specific neutralizing antibodies (NA) against PRRSV1-MLV were already detected at 14 d after vaccination in G1, showing a significant booster after the challenge, while PRRSV2-MLV NA were detected in G2 at the end of the experiment. Conclusions: Despite genetic differences, PRRSV1-MLV has been demonstrated to confer partial protection against a Japanese PRRSV2 strain, at least as good as PRRSV2-MLV.

• 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.

• BMB Reports
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• v.49 no.4
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• pp.226-231
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• 2016

Epstein Barr virus (EBV)-encoded nuclear antigen-1 (EBNA1) plays a pivotal in an EBV episome replication and persistence. Despite considerable attempts, there are no EBV drugs or vaccines. We attempted to eradicate EBV episomes by targeting EBNA1 using the transcription activator-like effector nucleases (TALEN) (E1TN). E1TN-mediated transient knockout (KO) of EBNA1 reduced EBNA1 expression, and caused significant loss of EBV genomes and progressive death of EBV-infected cells. Furthermore, when a mixture of EBV-infected Burkitt's lymphoma (BL) cells and EBV-negative BL cells was targeted by E1TN, EBV-negative cells were counter-selected while most EBV-infected cells died, further substantiating that EBNA1 KO caused selective death of EBV-infected cells. TALEN-mediated transient targeting of EBNA1 attenuated the growth of EBV-infected cells, implicating a possible therapeutic application of E1TN for EBV-associated disorders.

• IMMUNE NETWORK
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• v.13 no.3
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• pp.81-85
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• 2013

The mucosal surfaces are constantly exposed to incoming pathogens which can cause infections that result in severe morbidity and/or mortality. Studies have reported that mucosal immunity is important for providing protection against these pathogens and that mucosal vaccination is effective in preventing local infections. For many years, the sublingual mucosa has been targeted to deliver immunotherapy to treat allergic hypersensitivities. However, the potential of vaccine delivery via sublingual mucosal has received little attention until recently. Recent studies exploring such potential have documented the safety and effectiveness of sublingual immunization, demonstrating the ability of sublingual immunization to induce both systemic and mucosal immune responses against a variety of antigens, including soluble proteins, inter particulate antigens, and live-attenuated viruses. This review will summarize the recent findings that address the promising potential of sublingual immunization in proving protection against various mucosal pathogens.

• Clinical and Experimental Pediatrics
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• v.49 no.3
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• pp.229-234
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• 2006

Varicella, which is mostly a benign disease, but also can cause considerable health burden in the community, can be prevented by immunization with live attenuated varicella vaccine. Higher uptake of varicella vaccine by universal immunization in North America has apparently been associated with decline in the number of reported cases of varicella, varicella-related hospitalizations, and the number of deaths caused by complications of varicella. On the contrary, there has been some reluctance in endorsing varicella vaccine for universal immunization in most of European countries. Concerns include unanticipated outbreaks of varicella among vaccine recipients, risk of varicella among unvaccinated adults, risk of herpes zoster among vaccinees as well as unvaccinees. Recently developed measles, mumps, rubella, and varicella combination vaccine and herpes zoster vaccine that may be licensed in the upcoming years may be the solution for varicella vaccine to be utilized in a greater scale. In Korea several varicella vaccine products have been utilized since late 1980. The adoption of varicella vaccine for universal immunization since 2005 along with the changing view in varicella prevention strategy mandates more studies for immunogenecity and efficacy of varicella vaccines as well as more surveillance to delineate the changes in epidemiology of varicella in Korea.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.271-272
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• 2002

Newcastle disease virus (NDV) vaccines were produced from Vero cells by using lively attenuated virus strain. The MOI of 0.1.' serum concentration of 2%. initial pH of 8.0. and infection time of 3 days were found to be optimum conditions for vaccine production. The treatment of polycation enhanced the virus production. When ascorbic acid was added as an antioxidant, NDV production was also enhanced. Utilization of $CaCl_2$ showed an inhibitory effect on the propagation of NDV. It was also found the ammonium ion concentration higher than 4mM inhibited virus production. Thus ammonium ion removal system was tried for the efficient production of NDV vaccine.