Sacbrood virus (SBV), a causative agent of larval death in honeybees, is one of the most devastating diseases in bee industry throughout the world. Lately the Korean Sacbrood virus (KSBV) induced great losses in Korean honeybee (Apis cerana) colonies. However, there is no culture system available for honeybee viruses, including SBV, therefore, the research on honeybee viruses is practically limited until present. In this study, we investigated the growth and replication of KSBV in cell cultures. The growth of KSBV was demonstrated by RT-PCR, quantitative real-time PCR, TEM and nucleotide sequence analysis. The results demonstrated that SBVshowed the replication signals in mammalian cell lines, including Vero cells without any signs of cytopathic effect (CPE). The results of RT-PCR, quantitative real-time PCR and in vivo infection with KSBV were also indicated the replication. Phylogenetic tree analysis shows our sequence included in distinct group with other SBV strains from China and Korea. It clearly showed the differenciation between field strain and attenuated strain through cell culture. The results of present study demonstrated for the first time that SBV like other animal viruses could be adapted and attenuated in cells through the sequential passages. The sequential adaptation through cell culture could result in discrepancy of pathogenicity of virus and morphological characterization. For this reason, the present results indicated that the cell adapted SBV could be a valuable tool to study the general properties of this emerging virus, including pathogenicity in the future.

The sensitivities of PrP Sc detection methods, western blotting (WB), immunohistochemistry (IHC) and protein mis-folding cyclic amplification (PMCA) techniques were compared from brains, spleens and blood of mice challenged with PrP Sc of murine-adapted BSE strain 301C. PrP Sc was detected in the spleen from 30 dpi by IHC and at 60 dpi by WB. At 30 dpi, disease-specific signals of PrP Sc was observed in only two follicles of a single spleen. PrP Sc was detected in spleen at 10 dpi with PMCA after 5 rounds of amplification. Clinical signs were obviously shown from 240 dpi, and coincided with first detection of PrP Sc in brains by WB, IHC and PMCA after one round amplification. In addition, PrP Sc was also detected in blood at 60, 180 and 240 dpi with PMCA after 5 rounds of amplification. The FDC-M1 epitope, which appears in immature FDCs, and PrP Sc were detected in follicles first at 30 dpi, whilst the FDC-M2 epitope of mature FDCs was detected at 60 dpi. More FDC-M2 epitope and PrP Sc were detected in follicles as disease progressed. The CD21/35 epitope is expressed on both FDCs and germinal center B cells. The pattern of CD21/35 expressing cells was similar to but less dominant than that of FDCs.

Nivalenol(NIV)의 검출을 위한 효소면역측정법(ELISh)을 개발하기 위하여 tetraacetyl nivalenol(Ac4-NIV)에 대한 다클론항체를 생산하고 그 조건을 확립하였다. Ac4-NIV-hemisuccinate를 bovine serum albumin에 공유결합 시킨 Ac4-NIV-HS-BSA를 Freund's adjuvant와 함께 수차례 토끼에 피하면역하였다. 가장 높은 항체가를 나타낸 항혈청으로부터 정제한 항체와 Ac4-NIV-HS-HRP conjugate를 이용하여 직접 경합 ELISA(cdELISA)를 확립하였다. 그 표준곡선으로 부터 Ac4-NIV의 검출범위는 10~5,000 ng/ml(ppb)임을 알 수 있었다. 특이항체의 Ac4-NIV과 acetyl T-2에 대한 반 응성은 각각 100, 70%였으나, NIV, deoxynivalenol, 3-acetyl deoxynivalenol, 15-acetyl deoxynivalenol, triacetyl deoxynivalenol, fusarenon-X, T-2에 대한 반응성은 0.1% 이하로 극히 미약하였다. NIV를 인위적으로 오염시킨 옥수수시료를 70% acetonitrile로 추출하고 acetylation한 다음 cdELISA를 행하였을 때, 분석의 회수율은 100, 300, 1,000 ng/g(ppb)에서 각각 108, 143, and 70%(평균, 107%)로 나타났다.