• Parasites, Hosts and Diseases
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• v.55 no.2
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• pp.143-148
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• 2017

Toxoplasma gondii infections occur throughout the world, and efforts are needed to develop various vaccine candidates expressing recombinant protein antigens. In this study, influenza matrix protein (M1) virus-like particles (VLPs) consisting of T. gondii rhoptry antigen 4 (ROP4 protein) were generated using baculovirus (rBV) expression system. Recombinant ROP4 protein with influenza M1 were cloned and expressed in rBV. SF9 insect cells were coinfected with recombinant rBVs expressing T. gondii ROP4 and influenza M1. As the results, influenza M1 VLPs showed spherical shapes, and T. gondii ROP4 protein exhibited as spikes on VLP surface under transmission electron microscopy (TEM). The M1 VLPs resemble virions in morphology and size. We found that M1 VLPs reacted with antibody from T. gondii-infected mice by western blot and ELISA. This study demonstrated that T. gondii ROP4 protein can be expressed on the surface of influenza M1 VLPs and the M1 VLPs containing T. gondii ROP4 reacted with T. gondii-infected sera, indicating the possibility that M1 VLPs could be used as a coating antigen for diagnostic and/or vaccine candidate against T. gondii infection.

• IMMUNE NETWORK
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• v.7 no.4
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• pp.186-196
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• 2007

Background: Although IL-12 has been widely accepted to playa central role in the control of pathogen infection, the use of recombinant IL-12 (rIL-12) as a vaccine adjuvant has been known to be ineffective because of its rapid clearance in the body. Methods: To investigate the effect of sustained release of IL-12 in vivo in the peptide and protein vaccination models, rIL-12 was encapsulated into poly ($A_{DL}$-lactic-co-glycolic acid) (PLGA). Results: We found that codelivery of IL-12-encapsulated microspheres (IL-12EM) could dramatically increase not only antibody responses, but also antigen-specific $CD4^+\;and\;CD8^+$ T cell responses. Enhanced immune responses were shown to be correlated with protective immunity against influenza and respiratory syncytial virus (RSV) virus challenge. Interestingly, the enhancement of $CD8^+$ T cell response was not detectable when $CD4^+$ T cell knockout mice were subjected to vaccination, indicating that the enhancement of the $CD8^+$ T cell response by IL-12EM is dependent on $CD4^+$ T cell "help". Conclusion: Thus, IL-12EM could be applied as an adjuvant of protein and peptide vaccines to enhance protective immunity against virus infection.

• Journal of Microbiology and Biotechnology
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• v.27 no.11
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• pp.2060-2069
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• 2017

Newcastle disease is a serious infectious disease in the poultry industry. The commercial vaccines can only offer limited protection and some of them are expensive and need adjuvants. At present, DNA vaccines are widely used. However, the immune responses induced by DNA vaccines are too slow and low. Here, we constructed the transfer vectors with a different number of C3d as molecular adjuvants (n = 1, 2, 4, or 6), and the vectors were cloned into the optimal eukaryotic expression plasmid (pVAXI-optiF) that expressed the F gene of Newcastle disease virus (NDV), and named pVAXI-F(o)-C3d1, pVAXI -F(o)-C3d2, pVAXI-F(o)-C3d4, and pVAXI-F(o)-C3d6, respectively. Cell transfection test indicated that pVAXI-F(o)-C3d6 showed the highest expression. In vivo immunization showed that the chickens immunized with pVAXI-F(o)-C3d6 intramuscularly induced better immune responses than the chickens immunized with the other plasmids. The protective efficacy of pVAXI-F(o)-C3d6 was 80% after challenge with the highly virulent NDV strain F48E9. The results in this study showed that C3d6 could be used as a molecular adjuvant to quickly induce an effective immune response to control NDV.

• 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.

• The Journal of Korean Society of Virology
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• v.27 no.1
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• pp.39-47
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• 1997

A large number of viruses belonging to Genus Hantavirus in Family Bunyaviridae are etiologic agents for hemorrhagic fever with renal syndrome (HFRS), or hantavirus pulmonary syndrome (HPS). Hantaan (HTN), Seoul (SED), Belgrade (BEL), Puumala (PUU) serotype viruses are well known causative agents for HFRS in Eurasian continent. Among those viruses Hantaan and Seoul serotypes are well known to cause HFRS in Korea, but there are some sporadic incidence by other than Hantaan or Seoul viruses. Recently we have developed the combined Hantaan-Puumala virus vaccine to prevent world-wide occuring HFRS. This combined vaccine is formalin inactivated, suckling mouse and suckling hamster brain extracts for Hantaan and Puumala viruses, respectively. Protein contents of this purified candidate vaccine is $27\;{\mu}g/ml$, which contains 1,024 ELISA antigen units to each virus, but content of myelin basic protein which is causing experimental allergic encephalomyelitis is less than 0.1 ng/ml. Thirty hamsters were given twice at one month interval intra-muscularly and bled on 30 days after each vaccination from retro-orbital sinus vein. Antibody titers were tested against 5 major serotype viruses, Hantaan, Seoul, Belgrade, Puumala and Sin Nombre viruses by IFA and PRNT. The mean IF antibody titers on 30 days after primary shot were 78.4, 68.8, 68.8, 37.9, and 15.6; mean neutralizing antibody titers were 65.4, 12, 6.1, 65.6 and 0.5 against Hantaan, Seoul, Belgrade, Puumala and Sin Nombre viruses, respectively. The mean IF antibody titers on 30 days after booster shot were 686.9, 567.5, 550.4, 516.3, and 430.9; and neutralizing antibody titers were 710.8, 41.9, 24.3, 409.9, and 1.6 against Hantaan, Seoul, Belgrade, Puumala and Sin Nombre viruses, respectively.

• Journal of Microbiology and Biotechnology
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• v.30 no.3
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• pp.313-324
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• 2020

Coronavirus disease 2019 (COVID-19), which causes serious respiratory illness such as pneumonia and lung failure, was first reported in Wuhan, the capital of Hubei, China. The etiological agent of COVID-19 has been confirmed as a novel coronavirus, now known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is most likely originated from zoonotic coronaviruses, like SARS-CoV, which emerged in 2002. Within a few months of the first report, SARS-CoV-2 had spread across China and worldwide, reaching a pandemic level. As COVID-19 has triggered enormous human casualties and serious economic loss posing global threat, an understanding of the ongoing situation and the development of strategies to contain the virus's spread are urgently needed. Currently, various diagnostic kits to test for COVID-19 are available and several repurposing therapeutics for COVID-19 have shown to be clinically effective. In addition, global institutions and companies have begun to develop vaccines for the prevention of COVID-19. Here, we review the current status of epidemiology, diagnosis, treatment, and vaccine development for COVID-19.

• The KIPS Transactions:PartC
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• v.9C no.2
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• pp.149-156
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• 2002

Current vaccine program which scans virus code patterns has a difficult to detect the encrypted viruses or polymorphic viruses. The decryption part of polymorphic virus appears to be different every time it replicates. We must monitor the behavior of the decryption code which decrypts the body of the virus in order to detect these kinds of viruses. Specialty, it is not easy for the existing methods to detect the virus if the virus writer has modified the loop count of execution intentionally. In this paper, we propose an advanced emulator using a new algorithm so as to detect various kinds of polymorphic viruses. As a result of experiment using advanced emulator, we found that our proposed method has improved the virus detecting rate about 2%. In addition, our proposed system has a merit that it runs on not only MS-Windows but also Linux, and Unix-like Platform.

• Journal of Microbiology and Biotechnology
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• v.10 no.3
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• pp.355-362
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• 2000

The Herpes simplex virus type 1 (HSV-1) glycoprotein B (gB) gene in the pHLA-21 plasmid was inserted into a baculovirus (Hyphantria cunea nuclear polyhedrosis virus) expression vector (lacZ-HcNPV) to construct a recombinant virus gB-HcNPV expressing gB. Spodoptera frugiperda cells infected with this recombinant virus synthesized and processed gB of approximately 120 kDa, which cross-reacted with the monoclonal antibody to gB. The recombinant gB was identified on the membrane of the insect cells using an immunofluorescence assay. Antibodies to this recombinant raised in mice recognize the viral gB and neutralized the infectivity of the HSV-1 in vitro. These results show that the gB gene has the potential to be expressed in insect cells. They also demonstrate that it is possible to produce a mature protein by gene transfer in eukaryotic cells, and indicate the utility of the lacZ-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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• v.30 no.1
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• pp.101-108
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• 2020

Infections by herpes simplex viruses have an immense impact on humans, ranging from self-limiting, benign illness to serious, life-threatening diseases. While nucleoside analog drugs are available, resistance has been increasing and currently no vaccine exists. Ginsenosides derived from Panax ginseng have been documented to inhibit several viruses and bolster immune defenses. This study evaluated 12 of the most relevant ginsenosides from P. ginseng for toxicities and inhibition of herpes simplex viruses types 1 and 2 in Vero cells. The effects of test compounds and virus infection were determined using a PrestoBlue cell viability assay. Time course studies were also conducted to better understand at what points the virus life cycle was affected. Non-toxic concentrations of the ginsenosides were determined and ranged from 12.5 μM to greater than 100 μM. Ginsenoside 20(S)-Rg3 demonstrated the greatest inhibitory effect and was active against both HSV-1 and HSV-2 with an IC₅₀ of approximately 35 μM. The most dramatic inhibition-over 100% compared to controls-occurred when the virus was exposed to 20(S)-Rg3 for 4 h prior to being added to cells. 20(S)-Rg3 holds promise as a potential chemotherapeutic agent against herpes simplex viruses and, when used together with valacyclovir, may prevent increased resistance to drugs.

• Journal of Microbiology and Biotechnology
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• v.8 no.4
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• pp.361-368
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• 1998

The E2 protein of HCV (hepatitis C virus) is thought to have a potential role in the development of subunit vaccines and diagnostics. To express it by the insect cell/baculovirus expression (Bacu) system, we constructed a recombinant Autographa californica nuclear polyhedrosis virus (AcIL3E2), determined the most appropriate expression conditions in terms of host cell line and culture medium, and characterized the expressed HCV E2 protein. A culture system using Trichoplusia ni BTI-TN5Bl-4 cells and SF 900IISFM medium expressed a relatively high level of HCV E2 protein. It was revealed that its glycosylation properties and subcellular localization were almost the same as the ones in the mammalian cell expression system previously reported, suggesting the recombinant HCV E2 protein derived from our Bacu system can be utilized for development of a subunit vaccine and diagnostics. Interestingly, HCV E2 protein was not degraded at all even at 43 h post-heat shock in the heat shock-induced necrotic cells, probably due to its integration into the microsomal membrane, indicating that heat shock can be employed to purify HCV E2 protein.