표면발현(surface-display system)은 세포 또는 바이러스 표면에 목적 단백질을 고정하여 발현시킴으로써 목적 단백질에 대하여 독립적인 공간 구조 및 생물학적 활성을 부여하는 단백질 공학 기술이다. 또한 이를 이용하여 높은 중화항체 유도 및 대량생산이 가능한 삼량체의 형태로 항원 단백질의 발현 또한 가능하다. BES(baculovirus expression system)에서의 표면발현 기술은 번역 후 수정과정 및 복잡한 구조의 다양한 단백질의 발현이 가능하기 에 다른 숙주 기반 시스템보다 효율적이라고 보고되고 있다. 그러나 목적 단백질 외의 다른 표면 단백질과 발현 공간에서의 경쟁으로 목적 단백질의 낮은 생산량이 큰 문제점으로 지적되고 있다. 따라서, 이러한 BES에서 표면 발현의 생산 효율을 증대시키기 위하여, 동일한 표면 공간에 대한 단백질 간의 발현 경쟁에 대해 실험적으로 확인 후, 그를 해결하기 위하여 표면발현에 최적인 목적 단백질 발현을 위한 프로모터 선발 실험을 수행하였다. 이를 통해 BES에서 표면발현에 의한 목적 단백질의 생산 효율을 증대시킬 수 있음을 확인하였다.

The soluble epoxide hydrolase (sEH) plays a crucial role in insect immunity and development by metabolizing oxylipins such as EpOMEs and EETs. This study investigates sEH's involvement in insect antiviral response against Autographacalifornicanuclear polyhedrosis virus (AcNPV) infection. Viral infection assays were performed on Plutellaxylostellaand Marucavitrata, utilizing occlusion bodies (OB, via feeding) and budded virus (BV, through injection). Insect mortality was monitored every 12 h for up to 7 days. Our findings demonstrated a dose-dependent impact of both virus forms (OB and BV) on insects. Additionally, the sEH inhibitor, AUDA (12-(3-adamantan-1-yl-ureido) dodecanoic acid), was employed alongside the virus. The results indicated that combining AUDA with the virus increased insect mortality. Furthermore, fluorescence assays revealed the gradual movement of the virus from the gut to hemolymph and fat body. AUDA was observed to expedite virus infection. Moreover, sEH expression rapidly increased along with the viral infection in Spodoptera exigua. RNA interference of sEH expression enhanced the viral virulence against S.exigua. These suggest that EpOMEs play crucial roles in immune resolution against viral infection in insects.

Canine parvovirus-2 (CPV-2) has been reported worldwide as a major pathogen associated with acute hemorrhagic enteritis. The disease is a major infectious cause of death, particularly in young dogs. The earliest type of CPV-2 was replaced with three main subspecies, CPV-2a, CPV-2b, and CPV-2c, within a few years. Vaccination is carried out regularly, but the emergence of antigenic variants and the influence of maternal antibodies have limited the efficacy of commercial vaccines. New vaccines, such as the subunit vaccine, have been developed for alternative, safe, and effective vaccination. The baculovirus expression vector system (BEVS) is an excellent eukaryotic expression system with a high-level expression of foreign proteins and the ability of post-translational modification. Therefore, it is used widely to produce recombinant protein and subunit vaccines. In this study, the VP2 protein of CPV-2b cloned in the gateway vector system was generated using a baculovirus expression system in Spodoptera frugiperda (SF9) insect cells. Hemagglutination assay (HA) titers (24) were obtained, and the expression was detected in 6-His tagged VP2 and monoclonal antibody (mAb) against CPV-2 by western blotting. The VP2 protein of CPV-2b expressed in this study may provide a basis for a clinical diagnosis and vaccination applications for CPV-2.

A solid-phase competition enzyme-linked immunosorbent assay (ELISA), recombinant VP2 (rVP2) protein, and monoclonal antibody (mAb) were developed for the specific and sensitive detection of porcine parvovirus (PPV) antibodies in pig sera. A total of 1,544 sera samples were collected from breeding pig farms located in the Gyeongsangbuk-do Province in the Republic of Korea. The optimal operating conditions of SC-ELISA were as follows. The concentration of rVP2 proteins coated on the wells was 4 μg/mL, the swine sera were diluted 1:2, and the HRP-conjugated PPV VP2 mAb (9A8 clone) was used at 500 ng/mL. These results suggest that the SC-rVP-ELISA assay may be a valuable alternative to the current diagnostic tools used to detect PPV-specific monoclonal antibodies and broadly monitor PPV infections in domestic pigs at different breeding stages.

Canine parvovirus (CPV) remains a leading infectious cause of death in canines, especially in young puppies. Though vaccination is being carried out regularly, immunization failures occur, and puppies may be exposed to infection. Virus-like particles (VLPs) act like a subunit vaccine, mimicking the structure of authentic viruses. Therefore, VLPs have the potential to be used as vaccine candidates. Since Viral Protein 2 (VP2), a major structural protein of CPV, is the crucial antigen for CPV, the purpose of this study was to produce a recombinant VP2 of new canine parvovirus-2a using the baculovirus expression system in SF9 insect cells. The results revealed that recombinant VP2 assembles to form VLPs with antigenic properties similar to those of natural CPV, the recombinant VLP can produce a hemagglutination assay (HA) titer (1:210) in SF9 cells. Expression of the recombinant 6-His-tagged VP2 in SF9 cells was confirmed by western blotting. These findings suggest that the recombinant VP2 expressed in this study could be used as an efficient subunit vaccine against CPV infection.

Viral protein 2 (VP2), which is the structural protein of parvovirus, can produce virus-like particles (VLPs) by a self-assembly process in vitro, making VLPs attractive vaccine candidates. VP2 of canine parvovirus (CPV) is responsible for neutralizing antibodies in immunized animals. In this study, VP2 protein of canine parvovirus-2c was expressed using a baculovirus expression system and assembled into parvovirus-like particles in insect cells. The results show that VP2 proteins assembled into virus-like particles (VLPs) with antigenic properties similar to those of natural CPV and a high hemagglutination (HA) titer (1:27). The recombinant 6-His-tagged VP2 protein with a molecular mass of about 65 kDa was detected by anti-His antibody and anti-PPV serum. This study provides a foundation for the application of VP2 protein in the clinical diagnosis of CPV and in the vaccination against CPV.

Viral protein 2 (VP2) of porcine parvovirus (PPV) is responsible for inducing neutralizing antibodies in immunized animals. It is the major viral structural protein. In this study, novel subunit vaccines against PPV based on virus-like particles (VLPs) formed from VP2 proteins (PPV 13-7 Korean strain) were expressed in an insect baculovirus cell system and purified using Ni-NTA affinity column chromatography. These VP2 proteins assembled into virus-like particles (VLPs). They showed antigenic properties similar to those of natural PPV. In addition, they showed high hemagglutination (HA) titers (211 for PPV 13-7 Korean strain). This study provides a foundation for the application of the difference immunization of recombinant protein in the diversity of PPV VP2 genes and in vaccination against PPV in the future.