Abstract: Bovine interferon λ3 (BoIFN-λ3) is a new type of interferon, and it can be employed to prevent and control bovine infectious diseases. Higher expression of BoIFN-λ3 can be achieved in Bombyx mori baculovirus expression system. Firstly, the Kozak sequence was inserted into upstream of optimized BoIFN-λ3 gene, which was cloned to transfer vector pVL1393, and recombinant plasmid of pVL1393-BoIFN-λ3 was constructed. The recombinant silkworm baculovirus with BoIFN-λ3 gene was acquired by employing silkworm baculovirus expression system previously constructed in our laboratory. The recombinant virus was infected with 5th instar larvae of Bombyx mori, and expression product of BoIFN-λ3 was achieved in hemolymph of silkworm. Here a recombinant vesicular stomatitis virus expressing green fluorescent protein (VSV/GFP) and MDBK cells were used to develop an antiviral assay for BoIFN-λ3, and the antiviral activity was about(2.7±0.12)×105 U/mL. Recombinant baculovirus was purified through plaque assay, and antiviral potential expressed by purified baculovirus demonstrated (8.1±0.52)×105 U/mL. The expression efficiency improved by 3 fold. Silkworm-baculovirus expression system is a novel method to produce high quality BoIFN-λ3.

Key words: bovine λ3 interferon, silkworm-baculovirus expression system, antiviral activity assay

摘要： 牛λ3干扰素(BoIFN-λ3)是一种新型干扰素，可应用于牛传染性疾病的防治。在家蚕杆状病毒表达系统中可实现BoIFN-λ3的高效表达。首先在优化合成的BoIFNλ3基因起始密码子上游引入Kozak序列，将其克隆至转移载体pVL1393，获得pVL1393-BoIFN-λ3重组质粒。利用本实验室构建的家蚕杆状病毒表达系统，获得整合BoIFN-λ3基因的重组家蚕杆状病毒，将重组病毒感染五龄起蚕，在蚕血淋巴中得到表达产物BoIFN-λ3。采用微量细胞病变抑制法在MDBK/VSV*GFP 系统检测蚕体中表达BoIFN-λ3的效价可达（2.7±0.12）×105 U/mL，利用空斑筛选法筛选重组病毒，测得最高表达量的重组病毒表达的BoIFN-λ3的效价可达（8.1±0.52）×105 U/mL，表达量提高3倍。家蚕杆状病毒表达系统为优质高效的牛λ3干扰素产品的生产提供了一种新方法。

关键词: 牛λ3干扰素, 家蚕杆状病毒表达系统 , 抗病毒活性检测